As noted in Part I of this series, cleanliness is crucial to all equipment components—not just hydraulic equipment. In general, the tighter the clearances, the cleaner the fluid must be. Rolling element bearings have tight clearances with thin lubricant films. Table I illustrates rolling element life extension based on fluid cleanliness. Knowing that fluid cleanliness is important in equipment longevity, the next question is how clean does my fluid need to be and what kind of filtration is needed to achieve these levels.

Cleanliness targets The most sensitive components in a hydraulic are the directional control valves that usually dictate the cleanliness standards for the whole system. If only valve type and pressure conditions are known, a generalized ISO cleanliness code, as illustrated in Table II, can be used as a reference. Bearings also require clean fluids. ISO cleanliness requirements for bearings are shown in Table III.

Mike Boyd of Fluid Solutions has developed a simplified way of being more specific, based on equipment conditions, in determining system cleanliness requirements for both hydraulic systems and gearboxes. This simplified method can be seen in Fig. 1 and Fig. 2 (see page 10).

Both Pall and HY-PRO filter companies have a method for calculating hydraulic system ISO cleanliness codes based on a large number of variables. Adapted from the British Fluid Power Association, a summary of this method is illustrated in Table IV.

Filtration requirements Selecting the most optimal cleanliness program requires the following:

• Select the ISO cleanliness code to be achieved (previously discussed)
• Select the correct placement for the filters
• Select the correct filter sizing to achieve the desired cleanliness code

Hydraulic systems have a number of options on filter placement, including the three illustrated in Fig. 3. A fourth filter placement option with servo valves involves a control circuit filter placed just before the valves.

Cleanliness targets can be achieved with a pressure line filter alone or with a combination of various filter locations. As provided by HY-PRO, Table V notes the filter sizing to achieve various cleanliness codes with one filter containing a Beta ratio of 1000.

It must be must be emphasized that Table V is solely for illustrative purposes—and ONLY for HY-PRO filters. Each filter manufacturer has tables for its own cleanliness guidelines. Filter ratings based on the new test dust (>4μ, 6μ, 14μ) will be coarser for the same cleanliness code than the old test dust (>2μ, 5μ, 15μ).

Filter manufacturers use the Multi-Pass Filter Test to establish filter ratings in achieving cleanliness codes. (This test was discussed in Part I of this series.)

The Multi-Pass Filter Test is run at both constant and varying flow to simulate a hydraulic system as closely as possible. It can be run under many different conditions, including viscosity of fluid, amount of test dust added, flow rate, terminal pressure drop, etc. This testing is used to develop filter media to achieve different cleanliness targets. Because high levels of test dust are constantly added in the Multi-Pass Filter Test, high beta ratios compared to what is actually measured in the system are usually obtained. The same filter rated on an actual system may show a much

lower efficiency. As an example, a filter on the Multi-Pass test rated at 6μ showed a beta ratio of 3000. When analyzed in the system, the actual beta ratio was only 3, but the cleanliness targets were met with the filter because a steady state condition had been reached in particle removal. Not many new particles were entering. The point here is that the way to evaluate filters is not strictly on beta ratios, but rather on how they perform in the system.

Achieving your requirements The most effective way to achieve your cleanliness code requirements is to optimize your filter placements and their size. The Parker Hannifin handbook is a particularly helpful reference in that it lists cleanliness requirements for various components and the filter requirements. As an example, for servo valves the handbook lists three different filter placement combinations: pressure, pressure & return line and pressure & offline. Many times, using a lower priced return line and/or offline filter will be more economical with the same results because a less expensive, coarser pressure line filter may be used. The four different filter options are as follows:

Pressure line filter…

• High cost
• Protects sensitive components downstream of pump
• Sees total system flow
• Bypass options

Control circuit filter…

• Directly before sensitive valve and
  will only filter fluid to that component
• Protects sensitive valves
• Cost effective when used in combination
  with return and/or offline filters
• High collapse option

Return line filter…

• Typically sees total system flow at low pressure
• Cleans ingressed and generated contaminants
• Low cost to weight of dirt removed

Offline filter…

• Low pressure
• Constant flow
• Capable of optimizing system at low cost
• Filter changed without system interuption

The impact that various filter options can have on a system can be seen in the following example. Here, a hydraulic system was using a 3μ control circuit filter and a 10μ return line filter. By changing to a 3μ return line filter, the particles >4μ were reduced tenfold and the control circuit filter could have been changed to a coarser grade to achieve the same previous cleanliness target.

Conclusion
The key to any reliability-based program is to develop a successful cleanliness control program. This is done by minimizing contaminant ingression through a cost-effective filtration program based on the following criteria:

• Setting of cleanliness requirements based on objectives and equipment type
• Selection of optimum filter placements
• Selection of filter sizing

Utilize your filter manufacturers in evaluating your systems and building the cleanliness control program(s) to meet your requirements.

Coming up next time 
The final article in the series will present case histories on the economics of effective filtration programs.

Acknowledgments:
The author thanks HY-PRO, Pall and Parker Hannifin for providing useful information for this article. Particular thanks go to Mike Boyd of Fluid Solutions for his mentoring on filtration principles and providing valuable information.

(Editor's Note: In Part I of this series— Sept./Oct. 2007, pgs. 34-38—Fig. I and Fig. II were provided by Parker Hannifin. They were referenced incorrectly, and we regret the oversight.)

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLE-Certified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526.

While a common differentiation of general purpose (GP) and special purpose (SP) steam turbines is indeed made at 1 MW, process industry users frequently have deviated from this rather arbitrary rule. Reliability professionals often have specified general purpose turbines if there were some spare capacity or if there were redundancy in the form of installed spares, or nonessential services, or moderate speed and so forth. A good example is a plant where there were several 2 or 3 MW GP steam turbines driving cooling water pump sets. Here, it would be very uneconomical—even wasteful—to insist on SP turbines.

Examples in the opposite direction exist as well. Take, for instance, a 600 kW steam turbine selected to drive a small, but essential, process gas compressor. In this situation, a special purpose steam turbine would be specified for very good reasons. It will cost more than the GP version, but it will have a lubrication system that makes it less prone to cause unscheduled outages.

Keep hybrids in mind 
Hybrids are a composite of GP practice and SP practice. Packaged systems may have to be upgraded by identifying the (potential) weak link(s) and specifying certain elements that are otherwise primarily associated with GP or, conversely, SP equipment.

Competent engineers frequently will specify hybrid support systems, such as lube oil consoles (Fig. 1), electronic governors, oil mist lubrication (Fig. 2) or oil flinger disks, instead of potentially unstable and risk-inducing slinger rings, etc. Even the rather customary carbon seal rings that have been supplied for seven or more decades with GP steam turbines are due for an upgrade. Forwardlooking users are now often replacing carbon rings with high-temperature mechanical seals and, in doing so, reduce both operating and maintenance expenditures.

Best judgment 
The best judgment of competent reliability engineers uses lots of experience and sound life-cycle cost assessments. The practices endorsed by these engineers often lead established industry practices and written standards by a decade.

Sound judgment recognizes that the life cycle of a machine is inevitably influenced by operating and maintenance practice. These practices have been the subject of thousands of written pages in books and articles. Moreover, they vary from location to location and are difficult to generalize across the board. While the practitioners may be disinclined to share this information, we nevertheless can observe what true reliability professionals do: They look at the specifics of each case and carefully weigh the alternatives. They will then submit their findings to responsible management in writing.

Lubrication frequency and oil analysis

Real-world questions… 
Questions on re-lubrication frequencies and how these are to be determined recently have been explored by some readers, as have issues relating to fitness for service or extending the life of existing oils. Of course, the major lube suppliers provide products and services—either directly or through contract distribution channels. They also offer lube oil analysis as part of the supply contract.

Some plant engineers seem to have engaged the services of major and minor suppliers without regrets, and they have pointed out reductions in both lube amounts and the number of different oil types being inventoried. One of our readers noted that his company is now using a single or a couple of oil types and maybe just one grease. "Yet," he went on to write, "I'm not so sure this consolidation is the best way, as you could end up being held to ransom, and maybe not get the best properties of oil for expensive equipment. I would be interested to hear your opinion on this subject."

The same reader had looked at oil sampling valves and wondered which was best; he also noted copper greases were not to be used at his olefins site. He found two products that enjoyed name recognition and attempted to narrow it down to the best one. In terms of oil analysis sampling points, he opined that primary and secondary locations might be justified in some cases. Likening it to his analogous experience in vibration monitoring and analysis, he determined there was no need for "overkill of data" or complexity of the sampling system. "Data overload and complexity," he stated, "might tend to become problematic and maintenance-intensive."

Our reader pointed out, just as is the case with vibration analysis, that there is not the same need for detailed knowledge in all foreseeable instances. There are times when identifying the defective bearing component may be less important than simply knowing that the bearing should be replaced and determining the optimum time to effect the change-out. He indicated that component identification will obviously aid in finding certain root causes, and reliability engineers should strive to have a balanced approach.

Because the reader looked forward to our supplementary comments and thought his letter (and our answer) would be of interest to others, we are pleased to share this information.

Real-world answers… 
Certainly, the bulk of this reader's questions have been answered in many currently available books and articles. Without taking the time to go into more detail, the use of a single type of grease for all applications in a modern olefins plant will lead to two alternatives. To maintain reliability and on-stream time would defi- nitely require more frequent preventive maintenance. If this diligent maintenance effort is not expended, the plant will give up a measure of reliability. If, then, an equipment user in such a facility is willing to sacrifice equipment reliability and equipment run length, he might opt to use a single grease type. However, the one advocating a single type of grease should be asked about ultimate life-cycle cost of the machines so lubricated. If the advocate were to take the time to study life-cycle cost, he might find some surprise answers. If he does not take the time to study the matter, he's just guessing and is thereby putting his plant at risk.

A similar statement could be made if an olefins plant had been persuaded to limit its oil types to just one or two. The probability of such a facility gaining Best-of-Class status is so close to zero that it is certainly not worth debating. Nevertheless, some consolidation of lubricants is feasible, as long as one looks at the lube requirements item-by-item and machine-by-machine. Sweeping generalizations are just that, i.e. sweeping generalizations are rarely adding value in a reliability-focused process plant environment. We are not familiar with the preferred brand of oil sampling valves. We are, however, reasonably familiar with some providers of oil analysis. Some folks advocate this predictive approach in situations where it makes absolutely no economic sense. The times and places and frequencies where sampling and analysis make sense are again discussed in many books and merit closer study. Having a preferred lubricant provider often is feasible and sometimes even beneficial. Unfortunately, there are also instances where this provider tries to sell the user too much stuff, or the provider's representative is inexperienced or neglects a user's account because he prefers to expend most of his energy finding new customers. There also have been instances where the lube provider does not offer the most suitable oil and then makes the user-buyer his test bed for trial-and-error solutions.

In summary, there will never be a substitute for the user educating himself/ herself on these issues. Whenever some users think training is expensive, we often ask them to calculate the expense with no training! Whenever they tell us they have no budget to purchase books, we leave them to do what they've become accustomed to accept as their normal routine: repair, repeat the repair, and repeat the repair again…

Contributing editor Heinz Bloch is the author of 17 comprehensive textbooks and over 340 other publications on machinery reliability and lubrication. He can be contacted directly at: hpbloch@mchsi.com

TRICO CORPORATION
Trico's Gear and Lube Oil Filtration System eliminates the problem of filtering lubricants with viscosities greater than 500 SUS @ 100 F. Capable of filtering oils up to 10,000 SUS @ 100 F, it has a 4 gpm flow capacity. Fluid compatibility includes most petroleum-based oils, including hydraulic, gear, turbine, transformer and motor oils, among others. Ensuring that equipment receives the cleanest oil possible, as well as maintaining long element life and pump protection, four-stage filtration is provided. The Trico system also features differential pressure gauges that indicate when each of the filtration elements needs to be changed. Two sampling ports are included for safely sampling and monitoring the condition of the oil. The system is available in two models—a Hand-Held System and a Portable Cart System.

Trico Corporation 
Pewaukee, WI 
www.tricocorp.com

HY-PRO FILTRATION 
Hy-Pro offers a wide range of portable filtration systems for conditioning fluid before use, during transfer and while in the system. Designed for hydraulic and lower-viscosity lube oils, the FC series features two spin-on filters mounted in sequence for multiple combinations of particulate and water removal. The FCL (pictured) is designed around a large coreless, high-efficiency filter element and well suited for conditioning high-viscosity bearing and gear lubricants. A toploading housing provides ease of element service and minimal mess. Hy-Pro's standard carts are available up to 22 gpm and any voltage necessary, including explosion-proof. True differential pressure gauges give an exact indication of element condition. Oil sampling ports are standard before and after the filter elements. Other options include pneumatic or hydraulic power and integrated particle monitoring.

Hy-Pro Filtration 
Fishers, IN 
www.filterelement.com

HARVARD CORPORATION 
Harvard's filtration systems clean oils and water glycol fluids. Their unique depth-type filtration is capable of removing 0.5 micron particulates and water from oils down to 50 parts per million, and clean them to ISO 12/8/6 or better. Harvard's filter systems can be made to order for diesel fuel, up to ISO 1000 viscosity. Also available are small handcarry systems with 1 gpm flow, wheeled carts with 20 gpm flow and optional bag filters, magnetic pre-filters, flow meters and particle counters. Customized systems can be ordered with flow rates of 200 gpm and a wide range of voltage requirements.

Harvard Corporation 
Evansville, WI 
www.harvardcorp.com

HYDAC TECHNOLOGY CORPORATION HYDAC Technology Corporation offers Single and Dual Stage Filter Carts to transfer and filter hydraulic fluids at rates of 7 or 14 gpm. The HYDAC OFCS and OFCD Series are compact, self-contained systems with high-efficiency, high-capacity filter elements capable of removing particulate contamination and/or water quickly, conveniently and economically. They are suitable for cleaning up existing systems and for pre-filtering new fluids. The OFCS single filtration unit can remove either water OR particulate contamination. The OFCD dual filtration unit can be used to remove both water and particulate contamination, or for staged particulate contamination removal.

HYDAC Technology Corporation Bethlehem, PA www.hydacusa.com

DES-CASE CORPORATION Des-Case offers users an economical way to customize their portable filtration needs. Two products from the FlowGuardTM line—filter carts and "drum toppers"—can be easily moved as needed/where needed to those applications that do not require constant filtration. The compact "drum topper" filtration unit allows you to take filters into tight places you couldn't reach before. Weighing approximately 55 pounds, these drum-topper products are light enough to carry onto platforms and under equipment that cannot be reached with a traditional cart. All FlowGuard products can be custom-designed online. Customers can select from a variety of filters, flow rates, ports, connectors, adapters, hoses and colors to meet the specific needs of their application.

Des-Case Corporation White House, TN www.des-case.com

IFH GROUP, INC. IFH (Innovative Fluid Handling) Systems offers the E.S.P. mobile lube maintenance cart. Standing for "Efficient, Safe and Productive," E.S.P. carts are available in more than 75 different variations. They feature a modular design that allows users to install different size containers on the same cart and use a different type of pump with each container. Users also can pull any cart off at any time and replace it with a different one. An E.S.P. cart can be created with any combination of containers, pumps, filters, meters, reels, storage space and more..

IFH Group, Inc. 
Rock Falls, IL 
www.ifh-group.com

KLEENOIL USA INC. 
Kleenoil’s Mobile Filtration Cart is a multi-purpose, fl uid cleaning and transfer machine for use with most hydraulic, gear, transmission and engine fl uids. The specially designed Kleenoil fi lter can achieve an ISO 4406 Cleanliness Code of 14/9, well below the original standards of the equipment’s original manufacturers and distributors. The Kleenoil cart will fi lter particles down to 1 micron, remove 99.95% of all water and minimize the amount of dirt and debris within a machine. As a result, repair and maintenance costs are reduced, greatly extending the life of engine and hydraulic equipment.

Kleenoil USA Inc. 
Plano, TX 
www.kleenoilusa.com

Y2K FLUID POWER, INC. 
Y2K Fluid Power offers several portable fi ltration systems with various functions, abilities and performance. Manufacturing in-house, Y2K always is designing new and customized lube cart models. Its new PT Series fi lter cart is an all-in-one portable oil tote and fi lter unit. It can be set up with a new oil tank or with new and used tanks with separate pumps to reduce contamination. This system can pump new or waste oils or serve as an off-line fi lter cart. A diamond-plate tool box and portable oil tray for storage of smaller containers also is available.

Y2K Fluid Power, Inc. 
Stacey, MN 
www.y2kfl uidpower.com

SCHROEDER INDUSTRIES 
Schroeder offers the Auto Flush Filter Cart (AFM) for staged particulate or water/particulate removal from hydraulic fl uid. The user-friendly AFM comes complete with the Schroeder Test- Mate Contamination Monitor® (TCM), making it easy for users to continuously monitor ISO levels in real time. A Siemens PLC provides an easy-to-use operator interface and an RS-232 port allows data to be downloaded to a PC. The AFM cart can run in either automatic or manual mode. Other options include a variable frequency drive and a water sensor that provides water saturation and temperature readings.

Schroeder Industries 
Leetsdale, PA 
www.schroederindustries.com

Ken Bannister, Contributing Editor

Who among us hasn't seen—or heard of— one or more of the recent "scary" documentaries "An Inconvenient Truth," "Crude Awakening" and "The Death of the Electric Car"? Who among us hasn't formed an opinion on global warming, the Kyoto Accord on industrial emission reductions and high energy costs? Individually or collectively, these things have heightened our awareness of serious issues affecting industry's future— and our own.

Many maintenance and reliability professionals I have spoken with over the past two years have begun developing a social conscience in regard to energy waste and pollution matters. Realizing, though, that a concerted effort is the only way to make a real difference in their operations, more than a few of these individuals have become quite frustrated by the absence of the vision and organization needed to get started down this path.

The "boon" years of the past three decades saw corporations making huge profits, in spite of themselves and their ineffective practices. These days, things are different. Global competitiveness has turned us all into savvy consumers who look for high-quality, rock-bottom-priced goods that are manufactured by "Green" suppliers. This new mindset is forcing companies to examine their production and maintenance operations and practices more closely than they once did, with an eye toward making them more effective, more energy efficient and more environmentally friendly— all at the same time.

With up to 70% of all mechanical failures directly and indirectly attributable to ineffective lube practices, implementation of a world-class lubrication management program is arguably the easiest and most effective improvement program in which a company can invest. Not only is such a program immediately effective in terms of increasing equipment availability, utilization and life cycle, when set up correctly it delivers considerable positive environmental impact through its contamination control and energy management components. Furthermore, such a program takes very little—if any—capital outlay to implement.

Environmental ROI 
From an environmental standpoint, a lubrication management program is a gold-plated change catalyst that pays off in many ways, including:

• Reduced on-site inventories of lubricants through the lubricant consolidation process
• Reorganized and cleaned-up lubricant storage areas with spill control management in place
• Improved lubricant storage, handling and transfer methods, resulting in improved contamination and filtration control that significantly reduces lubrication system and equipment leakage
• Reclamation and reuse of spilled lubricants

Energy ROI 
Energy management experts now recognize effective lubrication as a major strategy in energy reduction. Using the right lubricant in the right amount greatly reduces energy losses caused by friction. For example, a simple switch to a synthetic in a screw type compressor resulted in energy savings of 7.3%. A lubrication delivery system tune-up and change to a premium lubricant on a 500- ton straight side press resulted in 17.9% energy savings.* In each case, both equipment availability and lube change-out intervals increased.

These savings are not unusual—they're typical. More importantly, with many corporate annual energy bills running into millions of dollars, these savings can translate into tens to hundreds of thousands of dollars annually. In fact, many lubrication program implementations now are being funded solely on energy ROI, with uptime and availability stated as a residual benefit!

Think about it. Isn't time for you and your organization to go "Green?" Good Luck!

*Source: Energy Reduction Through Improved Maintenance Practices, Kenneth E. Bannister, Industrial Press, NY, 2006.

LEBLANC ANNOUNCED AS NEW CEO OF GENERAC 
Waukesha, WI-based Generac Power Systems has announced the appointment of Edward A. LeBlanc as CEO of the company. He takes on this new position in light of former CEO William Treffert’s recent decision to retire from Generac after 31 years of service.

LeBlanc, who has more than 20 years of executive management experience in the industrial and consumer products sectors, has been serving as non-executive chairman of Generac’s board of directors for the past year. Immediately prior to joining Generac, he had been serving as president and CEO of the Residential and Commercial Division of Kidde, plc, a supplier of fi re protection equipment.

NYQUIST APPOINTED PRESIDENT EMERSON PROCESS GLOBAL SALES
Emerson Process Management has announced the appointment of Jim Nyquist as president of Global Sales. He will be directing sales operations for all company divisions (systems, software, instruments valves and services). In his 30-year career with Emerson, Nyquist has served in a number of world area roles in the Americas, Europe and Asia, including, most recently, as president of Emerson Process Management Europe.

BHATTACHARYA IS NEW PRESIDENT AT WONDERWARE 
Invensys plc has announced that Sudipta Bhattacharya is taking on a new role within the organization as president of the Wonderware business unit. Bhattacharya will report to Ulf Henriksson, CEO of Invensys. He replaces Mike Bradley, who had served as Wonderware president since November 2002. Bradley was instrumental in driving the company’s HMI and SCADA businesses, and then taking the company deeper into other manufacturing and infrastructure spaces.

JOHNSON CONTROLS BUYS CANADA’S THE CAPITAL GROUP 
Johnson Controls has announced its acquisition of The Capital Group, a mechanical services company headquartered in Ottawa, Ontario. Specifi c terms of the agreement were not disclosed. Founded in 1974, The Capital Group provides mechanical services for commercial and industrial customers throughout greater Ottawa. The company has approximately 82 employees.

FLIR ENTERS AGREEMENT TO ACQUIRE EXTECH INSTRUMENTS 
Extech Instruments has announced that the company’s president and owner, Jerry Blakeley, has entered into an agreement in which the stock of Extech will be acquired by FLIR Systems Inc. The transaction, which is subject to standard closing conditions, is expected to be completed within the fourth quarter.

According to Blakeley, the acquisition of his company creates new opportunities in distribution, product development and branding that will extend and strengthen Extech’s position in competitive markets. Known for its approach to product development, Extech has made extensive use of IR technology for both measurement and communication. The company holds fi ve patents incorporating IR into measurement instruments, and was the fi rst company to introduce a portable printer with IrDA wireless communication.

KAYDON CORPORATION ACQUIRES AVON BEARINGS 
Kaydon Corporation has announced that it has acquired Avon Bearings Corporation (“Avon”) in a cash transaction valued at $55 million. Avon is expected to add approximately $30 million to Kaydon’s fi scal 2008 sales. Headquartered in Ohio, Avon is a custom designer and manufacturer of high-precision large diameter turntable bearings. It also remanufactures bearings and sells replacement bearings. According to James O’Leary, president and CEO of Kaydon, this strategic acquisition is expected to help his organization accelerate growth in the wind energy arena, one of Kaydon’s major markets, while both strengthening existing customer relationships and adding others. In particular, he notes, the Avon addition will broaden Kaydon’s presence in important offshore crane, construction and steel markets for very large diameter bearings, while also providing access to the refurbishment market where Avon has built a leadership position over many years.

BENTLY CERTIFIED TO TEST FOR ULTRA LOW SULFUR DIESEL 
Bently Tribology Services (BTS) has announced that both of its labs (Peabody, MA and Minden, NV) are now EPAcertifi ed to test for ULSD (Ultra Low Sulfur Diesel).The EPA requires fuel marketers and all those in the supply chain to demonstrate an effective monitoring program to ensure compliance with new sulfur limits for both highway diesel, NRLM (Non-road, locomotive and marine) diesel and heating oil. BTS also offers full diesel and biodiesel fuel testing capabilities.

ATLAS COPCO LAUNCHES ITS FIRST SERVICE DIVISION Atlas Copco Compressor Technique is merging its customer service and spare parts operations into a dedicated service division. “By combining our service operations we will strengthen the cost competitiveness of the business and improve the service we give our customers,” says Ronnie Leten, president of Atlas Copco Compressor Technique. “This will serve to grow our aftermarket business and gives an increased focus also within the equipment divisions.”

The mission of the new Compressor Technique Service division is to be the global leader in customer service, providing all service of compressors needed by Atlas Copco customers, with an extended range of offerings. The gains from creating a single division include focused purchasing and the coordination of overlapping functions. The other operational divisions of Atlas Copco Compressor Technique are Industrial Air, Oil-free Air, Gas and Process, Portable Air and Specialty Rental.

According to the company, Atlas Copco has experienced increasing demand from customers to provide full packages of equipment, as well as service, training and spare parts. Atlas Copco’s business areas, Construction and Mining Technique and Industrial Technique, also have organizations in place for focusing on the service offering.

YOKOGAWA HELPS FOUND ISA SECURITY COMPLIANCE INSTITUTE Yokogawa has become a founding member the ISA Security Compliance Institute, an organization of industrial technology vendors and end users dedicated to establishing specifi cations and processes for testing and certifying control systems products.

The new organization will work to establish a set of wellengineered specifi cations and processes for the testing and certifi cation of security characteristics for critical control systems products.

Conformant products will carry the ISASecure designation, enabling suppliers to substantiate claims of compliance and provide asset owners with an independently validated identifi cation of compliant products when making procurement decisions.

Members, working with technical staff retained by the Institute, will develop a set of compliance requirements based on ISA99 security standards and other relevant standards, such as IEC or DHS recommendations. The program will be designed to cover everything from the device-level products up to gateway interfaces, to business planning and logistics systems.

FLUKE OFFERS INDUSTRIAL TEST TOOL EDUCATION GRANT 
Fluke Corporation will donate two of its high-performance Fluke 289 True-rms Industrial Logging Multimeters with TrendCapture to 10 qualifying educational institutions through a new education grant program. Designed to help ensure that educators, students and entry-level professionals have access to state-of-the-art technology, the program lets instructors in accredited programs apply for grants of the Fluke 289 for use in training students to diagnose problems in electronics, plant automation, power distribution and electromechanical equipment.

Members of the Fluke Education Partnership can apply for the grant by completing the application form available on the Partnership’s Website. The Partnership is a Webbased program offering educators in technical, university and apprenticeship programs free curriculum materials and a discount on all Fluke handheld test tools. Membership is free. Applications will be reviewed by a committee from Fluke for program elements, including breadth of course offering, degree/certifi cation qualifi cations and statistics, and plans for using the test tools within curriculum. The winners will be announced in February 2008.

FSA/HI MECHANICAL SEAL COURSE SET FOR 2008 MARTS 
The Fluid Sealing Association (FSA) (www.fl uidsealing. com) in conjunction with the Hydraulic Institute (HI) (www.pumps.org ), will conduct a pre-conference workshop entitled “Fundamentals of Mechanical Seals,” at the 2008 Maintenance & Reliability Technology Summit (MARTS), on Monday, April 14, in Rosemont, IL. Presented by instructors from FSA member companies, this comprehensive overview is crucial for those involved with the selection procurement, operation and/or maintenance of any equipment that utilizes mechanical seals—from new engineers to operators to maintenance personnel. Topics will include mechanical seal designs and arrangements; operating principles and application limits; seal chamber design and pressures; installation; environmental controls and piping plans; life cycle costing of mechanical seals and sealing systems; and troubleshooting. Attendees will receive a free copy of the authoritative HI/FSA book Mechanical Seals for Pumps: Application Guidelines (a $195 retail value) with their paid registration. For details, refer to the full MARTS brochure in this magazine or on www.MARTSconference.com. (EDITOR’S NOTE: Applied Technology Publications, parent of Maintenance Technology and Lubrication Management & Technology magazines and organizer of MARTS, is an affi liate member of the FSA.)

ASSOCIATION NEWS

SMRP CONFERENCE RECAP 
This year’s SMRP Fall Classic Conference, held October 7-10, 2007 in Louisville, KY, brought together record numbers of maintenance and reliability professionals and suppliers to the industry. According to conference organizers, more than 1000 attendees and 69 exhibitors took advantage of this year’s annual event and the professional development and networking opportunities it offered.

The Louisville gathering featured 50 technical presentations centered on the fi ve SMRP core bodies of knowledge, including business and management, manufacturing process reliability, equipment reliability, people skills and work management. A sixth track, SMRP initiatives and values, comprising an additional 12 presentations also was featured.

At the Annual Business Meeting, former vice chairman Tim Goshert was chosen to take Tom Byerley’s place as the chairman of SMRP in 2008. The SMRP Certifying Organization’s (SMRPCO) vice chair in 2007, Rich Overman, will serve as SMRPCO chairman for the 2008 term.

News that SMRPCO was approved as an ISO Accredited Certifying Organization by the American National Standards Institute (ANSI) on September 9, 2007 also was confi rmed. Since its fi rst exams in 2001, almost 2000 practitioners have obtained their CMRP certifi cation, including 281 in this year alone. Beginning January 1, 2008, the accredited exam also will be available as a computer-based test at more than 500 sites in the United States and Canada.

The SMRP Fall Classic was highlighted by another very special announcement regarding the establishment of a scholarship in honor of long-time, key SMRP and SMRPCO contributors Jack and Dorothy Nicholas. Known as the “Jack and Dorothy SMRPCO Scholarship,” it will be an annual award and offered to deserving students beginning in 2008.

For those planning early, next year’s SMRP conference is set for Oct. 20-23, 2008 in Cleveland, OH. For more information, visit www.smrp.org

YOUR NEWS IS OUR NEWS! 
OUR READERS WANT TO KNOW ALL ABOUT IT. 
SEND LMT NEWS ITEMS TO: jalexander@atpnetwork.com

Ken Bannister, Contributing Editor

Dickens crafted his "best of times, worst of times" line—a line that became one of the most famous openings in English literature—as a way to set a tone for his portrayal of events leading up to the French Revolution. Interestingly, this historical novel was written as another important revolution was taking place—one of the greatest to date—the Industrial Revolution.

Although Dickens was alluding to the contrast between "modern" 18th century ways of life and thinking in London and Paris, and the "traditional" brutality and suppression carried out by nobility and peasants alike, his thoughts also were likely influenced by the sweeping industrial and technological changes swirling about him at the time. No wonder his words seem so profound and insightful, and that they continue to be as relevant today as when he wrote them. Take, for example, the changes occurring within our own Information Revolution.

Never before has the world witnessed such sophisticated levels of technology and communication. As a result, however, we have become so reliant on technology that we have for the most part forgotten the fundamentals, forcing ourselves into a pervasive "replace vs. repair" mentality. This approach, though, stops being a viable strategy once the technology becomes depreciated, with no more replacement parts available.

Although today's communication is enacted at lightning speeds, the art of correspondence seems to be failing just as rapidly. While we appear to be enthralled by the amassing of vast stores of data, rarely do we take the initiative or time to turn this data into information through which true management decisions are made.

We also appear to have become so preoccupied with predicting failure that many have neglected— or have never learned—the basics of effective planning and scheduling to get the impending failure addressed prior to a catastrophic event. Likewise, cleanliness and lubrication, the cornerstones of virtually every new and existing physical asset management strategy, have never been better understood. Still, many companies today continue to neglect these most fundamental of machine care tactics.

Maybe now is the time to do things better. Let's take a leaf out of the "lean" strategy manual. Let's slow down the pace. Let's really know what we are trying to achieve. Let's build management strategies based on clear communication and the understanding of maintenance fundamentals when laying out our programs' foundations. To borrow more words from Dickens, these from the final line of a Tale of Two Cities, "It is a far, far better thing I do… " Today, we all can do better. Good luck!

Ken Bannister is lead partner & principal consultant for Engtech Industries, Inc. Phone: (519) 469-9173; e-mail: kbannister@engtechindustries.com

GE Enterprise Solutions reportedly will have annual revenues of approximately $11.5 billion. The new business includes GE's Equipment Services, Security, Sensing & Inspection, Multilin and Power Quality units, as well as the GE Fanuc Automation business. Enterprise Solutions also will work closely with the GE Energy Optimization and Controls business to broaden its current focus on the energy sector.

TIMKEN ANNOUNCES BIZ ALIGNMENT CHANGES 
The Timken Company has announced changes to align the organization around continued improvement in operational performance and acceleration of profitable growth. Under the new model, Timken will operate with two major business groups, the Steel Group and the Bearings and Power Transmission Group. Michael C. Arnold has been named as executive vice president and president, Bearings and Power Transmission Group. Salvatore J. Miraglia, Jr., will continue as president of the Steel Group.

Timken's new Bearings and Power Transmission Group includes four divisions: Mobile Industries, composed of the rail, off-highway, agriculture, heavy truck and passenger car and light truck market sectors; Process Industries, which encompasses the heavy industry, power transmission and energy market sectors; Aerospace & Defense, serving the friction-management and power-transmission needs of commercial and military aviation customers through OEMs and the aerospace aftermarket; and Distribution & Services, which provides a full range of bearings, seals, grease, condition monitoring and other products and services through distributors worldwide.

On a related note, Timken also has announced the appointment of Jacqueline A. Dedo as senior vice president, Innovation and Growth. In this role, Dedo will be responsible for leading the company's strategic initiatives to accelerate the pace of innovation and growth.

FUSS & O'NEILL PARTNERS WITH MICROMAIN CORPORATION 
MicroMain, a provider of asset and facility management software and services, and Fuss & O'Neill, a full service engineering consulting firm, have announced a new strategic partnership. Fuss & O'Neill provides services related to civil and environmental engineering, structural engineering, industrial plant services, building systems, manufacturing solutions, information technologies and design build. Headquartered in Manchester, CT, the company serves customers primarily on the East Coast. Under the terms of this new alliance, Fuss & O'Neill Technologies will integrate MicroMain™ software with other technologies including Geographic Information Systems and provide a data center for the operation of MicroMain software and other products. Fuss & O'Neill Manufacturing Solutions, which provides best practices training to maintenance organizations, will provide its services to customers using MicroMain's computerized
maintenance management system (CMMS).

WESTMORELAND SELLS POWER OP & MAINTENANCE
Westmoreland Coal Company has closed the sale of its power operation and maintenance businesses to North American Energy Services (NAES). Included in the deal were operation and maintenance contracts for four power plants owned by Dominion Resources (Altavista, Hopewell, Southampton and Gordonville), as well as certain fixed assets of Westmoreland Technical Services. Westmoreland also has contracted with NAES to provide contract operation and maintenance services at the company's 100%-owned ROVA power facility in North Carolina. Westmoreland previously had reported that it considers the transactions to be economically neutral. No further terms were disclosed.

MAINTENANCE TECHNOLOGY ANNOUNCES 2007 SALARY SURVEY
Just how much are you really worth in the reliability and maintenance arena? In today's operating environments, where so much seems to be riding on so many companies being able to stay up and running at maximum capacity, Maintenance Technology is sensing that your knowledge, skills and experience probably have more value for an organization than ever before. To verify this, however, our editorial team needs to go far beyond the anecdotal and gather more concrete data regarding the actual state of the employment marketplace.

Of course, we can't get the answers that we need without your help. That's why we're inviting you to participate in the 2007 Maintenance Technology Salary Survey. It's a very simple process. Go to www.zoomerang.com/survey.zgi?p=WEB226T3XL7CSB (or the Salary Survey link on www.MT-Online.com) and answer a few basic questions about your particular role, responsibilities, etc.

Rest assured that you will not need to identify yourself. Your responses, though, along with those of others, will be compiled into a report that will be published in the December 2007 issue of Maintenance Technology. To have your input included, we ask that you complete this brief survey by October 31, 2007.

Please keep in mind that the time you take now to fill out our 2007 Salary Survey should help you and other Reliability and Maintenance Professionals on your career paths well into the future. We really look forward to your participation.

ASSOCIATION NEWS

ACEEE ANNOUNCES CHAMPIONS OF ENERGY 
The American Council for an Energy-Efficient Economy (ACEEE) has named three Champions of Energy Efficiency for 2007. Winners were selected based on demonstrated excellence in program implementation, leadership, R&D, energy policy, private sector initiatives and international initiatives. The selections were made by ACEEE's Board of Directors from a field of 23 candidates nominated by their peers.

This year's "Champions" include Byron Lloyd and Mark Hamann, who were honored for Industrial Leadership. Through a partnership between the Illinois Department of Commerce and Economic Opportunity (DCEO) and ComEd, Lloyd and Hamann were instrumental in enhancing the use of Envinta's ‘One-2-Five' software to create a holistic energy-efficiency evaluation tool. Their joint effort resulted in a new evaluation and implementation product known as the Manufacturing Energy Effi-ciency Program (MEEP).

David Zepponi also was honored for Industrial Leadership. As president of the Northwest Food Processors Association, Zepponi has implemented numerous projects to develop continued energyefficiency gains in his industry. Among these projects, he has created, populated and maintained an informative database of Best Practices that include information on system optimization, best-available commercial technologies, energy- and water-saving measures and other leading-edge energy and environment technologies.

Finally, United Technologies Corporation (UTC) was honored for Implementation & Deployment. As a diversified company with products ranging from home heating and air conditioning to aerospace and helicopters, UTC has met impressive energyefficiency goals. These include a 19% reduction in energy consumption, a 49% reduction in water consumption and a 44% reduction in air emissions from 1997-2006. As part of its latest set of environmental targets, UTC has set a goal to reduce absolute greenhouse gas emissions by 12% over the next four years and will invest $100 million toward co-generation and energy-conservation projects. To learn more about ACEEE and its Champions of Energy Efficiency, go to www.aceee.org

Use the right transfer method
Studies by one of the world's most competent and experienced bearing manufacturers, SKF, have shown the exponential decrease in bearing life due to what some—erroneously—consider "minor" contamination. All too often, this contamination comes from oil transfer containers with open spouts, missing filler caps and rust and caked-on dirt. Where dirty containers (see left portion of Fig. 1) and unacceptable work practices are still the norm, even the best lubricants and most advantageous bearing housing seals will be of no help in attaining high equipment reliability. Hence, the replacement of questionable transfer containers with rustproof, suitably proportioned and purposefully designed oil transfer tools (right portion of Fig. 1) should be a priority issue for modern industrial plants. A quick-action push-pull valve incorporated in the spout allows for the adjustment of oil flow to the particular task demanded. The lid and spout arrangement of purposefully designed containers keeps oil in, and contaminants out. It has been shown that payback periods often can be measured in days [Ref. 1].

That said, the cost-effectiveness of these lubricant containers is quite selfevident. Responsible reliability professionals consider them essential lubrication management tools. Indeed, it makes much economic sense to first ensure lube oil cleanliness before contemplating any of the other, more glamorous, high-tech approaches to optimized lubrication.

Beyond proper lubricant transfer methods, though, there also is the issue of storage adequacy that affects fitness for use of lubricated components. The first and foremost of these are rolling elements—older terminology: "anti-friction" —bearings.

Proper storage of bearings 
Spare parts protection should be among the priorities for sound asset management. Proper storage of parts—and lubrication while they are being stored—may vary depending on component and configuration. Most rolling element bearings can be stored in their original packages for several years, but the storage facility and mode of storage must be correct. There are four general requirements that must be observed:

• The relative humidity in the storeroom should not exceed 60%.
• The temperature should be stable within reasonable limits, although no quantitative numbers are available. Aiming for a range between 0 and 40 C (32 and 104 F) and not allowing the temperatures to fluctuate more than 10 degrees C (18 degrees F) per hour seems reasonable here.
• Bearings must be laid down flat on the storage shelves. The loads acting on the rolling elements are now evenly distributed whereas, with "on edge" or standing storage, much of the load would act on just one or two of the bearing's rolling elements. Moreover, the weight of the rings and rolling elements in the standing position might cause permanent deformation because the rings are relatively thin-walled. Think of an apple pie—it would not make sense to store it on edge.
• Sealed or shielded bearings may have been pre-filled with grease whose lubricating properties are adversely affected by long-term storage. For these bearings, assume a twoyear shelf life, unless the grease (or bearing) supplier will certify a higher (or lower!) number that differs from the two-year rule. This issue then implies that reliability- focused users would refuse to purchase "surplus bearings." More often than not, cheap surplus bearings are ones that someone else has discarded because of uncertain age, unwise storage method and unknown provenance. Since cheap surplus bearings are unsuitable for use in machines at reliability-focused facilities, they should be relegated to duties such as paperweights, doorstops and boat anchors.

Protecting "inactive" machinery 
Machinery in storage must be protected from the elements. Painting, plating, sheltering, use of corrosion-resistant materials of construction and many other means are available to achieve the desired protection [Refs. 1, 2 & 3]. Although the protection of bearing housings is of primary importance in most fluid machines, a similar set of protection requirements applies to both "about-to-becommissioned" and "temporarily deactivated" equipment. The storage method discussed here refers to that "inactive machinery" category. The means or procedures chosen for the preservation or corrosion inhibiting of fully assembled, but inactive fluid machines will logically depend on the type of equipment, expected length of inactivity, geographic and environmental factors and the amount of time allocated to restore the equipment to service.

The basic and primary requirement of storage preservation is exclusion of water from metal parts that would form corrosion products—that means rust. These corrosion products could then find their way into bearings and seals. A secondary requirement might be the exclusion of sand or similar abrasives from close-tolerance bearing or sealing surfaces. All or any of the chosen storage preservation strategies must aim to satisfy these requirements.

Machinery preservation during pre-erection storage or long-term deactivation (mothballing) will have an effect on machinery infant mortality at the startup of a plant or process unit. Many times, machinery arrives at the plant site long before it is ready to be installed at its permanent location. Unless the equipment is properly preserved, scheduled commissioning dates may be jeopardized, or the risk of failure is greatly increased.

Long-term storage preservation by nitrogen purging is well known in the industry. Generally, this method of excluding moisture is used for small components, such as hydraulic governors or large components, such as turbomachinery rotors kept in metal containers. Nitrogen consumption is governed by the rate of outward leakage of this inert gas and may be kept at a low, highly economical rate if the container is tightly sealed. Alternatively, the container could be furnished with an orificed vent to promote through-flow of nitrogen at very low pressure. This is called "nitrogen sweep" or "nitrogen blanketing." Whenever the preservation of field-installed inactive pumps and their drivers is the primary objective, simply providing a moderate-cost oil mist environment will prove highly effective. Such oil mist preservation systems have contributed substantially to the flawless commissioning and operation of equipment in Best-of-Class or Best Practices plants. While it is, of course, feasible, applying a nitrogen purge will incur higher costs.

Oil mist preservation 

General setup… 

An oil mist console like the one normally used to lubricate rotating equipment will be used to generate a preserving mist. A large and a small console are shown in Fig. 2. Since none of the equipment is rotating, a basic unit without all the supervisory alarms and back-ups often will suffice. It is recommended that air and oil heaters be used to ensure mixing effectiveness and maintaining the correct air/oil ratio. These heaters are mandatory if ambient temperatures during the period of storage drop below 50 F (10 C). Typical R&O (rust and oxidation inhibited) turbine oils (ISO Grade 32) can be used in the mist generator lube reservoir to provide oil mist at an approximate header pressure of 20" of water column (~5 kPa).

A large oil mist console can serve hundreds of machines laid up in a temporary outdoor storage yard. One such location, often inundated by rain, is shown in Fig. 3. A storage yard in an arid part of the world will look no different (Fig. 4). A pipe header runs the length of the storage yard. Mounted along the way and at the top of the header are a number of manifolds (Fig. 5) into which reclassifiers are screwed. Plastic tubing connects the point of oil mist application at the machine to the reclassifiers. This is illustrated in Fig. 6, where plastic tubing leads to application points on a small turbine that is part of a lube oil skid. Note that even the oil reservoir is blanketed by oil mist.

It pays, however, to remember that actual on-site installed, spare or standby pumps and motors are being protected by oil mist. Oil mist both lubricates running equipment and protects non-running machines. This lubrication mode would gain even greater acceptance if these dual capabilities were being mentioned more often.

Getting back to temporary storage, some owners have occasionally elected to construct covered temporary storage yards. Storage under cover, though, is probably more for the benefit and convenience of inspection personnel—it is neither required nor cost-justified for equipment protection. Needless to say, storage in a warehouse also is feasible. Fig. 7 depicts oil mist applied to the equipment inside a half-open crate located indoors.

Storage site preparation… A few common-sense considerations will assist in defining long-term storage measures either indoors or outdoors:

1. Choose a site that has good drainage and is located out of the main stream of traffic. This will reduce possible mechanical damage from trucks, forklifts, cherry pickers and automobiles. A covered fenced storage area is preferred for the convenience of personnel, but it is not needed by the stored pumps, electric motors and other equipment.
2. Position stored equipment on cribbing (pallets) if the storage site has not been paved or concreted. Arrange the equipment in an orderly fashion with access for lifting equipment.
3. Install temporary overhead supports for the oil mist headers as per Figs. 2 and 3. Piping for the oil mist headers should be Schedule 40 screwed galvanized steel with minimum size of 1½". All piping should be blown clean with steam prior to assembly to remove dirt and metal chips. All screwed joints are to be coated with Teflon sealant (no Teflon tape) prior to assembly to prevent oil mist leakage.
4. Install laterals (½" min.) from top of mist header at each piece of equipment. Attach a distribution manifold to the header or to each lateral. Each distributor block typically has eight connection points in which to attach the ½" tubing. This should be sufficient to provide mist to most driver and pump combinations.

Pump and driver storage preparations… 
A typical connection sequence would include:

1. Connect ½" plastic or copper tubing from distributor block to reclassifier fitting attached to pump bearing housings. (See Fig. 3).
2. Connect ½" plastic or copper tubing from distributor block to reclassifier fittings located in pump and turbine suction flanges. If wooden, plastic or metal flanges are used, drill ½" hole through the suction flange protector to permit the insertion of the reclassifier fitting. Once reclassifier fitting and tubing are inserted in the suction flange, seal the hole with duct tape. This prevents moisture and dirt from entering the mechanical seal and wetted area of the pump by maintaining a positive pressure of oil mist. No vent holes are required because of normal leakage around flange protectors.
3. Electric motors modified for oil mist lubrication should be stored with oil mist flowing through the smallest size reclassifier attached at each bearing cavity. Electric motor hookups are very similar to those shown in this article's various illustrations. (Note oil mist venting from the steam turbine governor in the foreground of Fig. 3).
4. Coat all exposed machine surfaces with an asphalt-based preservative purchased from a reputable lubricant supplier. Re-coat exposed machine surfaces every six months if needed. The preservative may be applied by either spray or brush.
5. Rotate pump and driver shafts ¼ revolution each month to prevent brinnelling of anti-friction bearings and bowed shafts.

Oil mist generator maintenance

1. Check weekly to ensure that air supply is dry.
2. Refill mist generator oil reservoir weekly.
3. Perform weekly checks of air and oil heaters on mist generator.
4. Check oil mist header pressure daily. (Verify ~ 20" of H2O.)

To re-emphasize 
Equipment preserved by oil mist blanketing can be stored for years with minimum maintenance and cost. The photograph in Fig. 7, dating from the early 2000s, shows the thoughtfulness and professionalism that have brought us to modern oil mist preservation. It is assumed that the internal surfaces of equipment stored in boxes and wooden crates will have been coated with a light film of preservative oil. For both indoor and outdoor storage, the various equipment-internal volumes are kept at slightly more than atmospheric (ambient) pressure. Oil mist through-flow is being achieved by providing a small vent at the bottom of the equipment casings blanketed with this oil mist environment.

Whenever possible, the equipment purchase documents should state that oil mist will be used as a long-term storage means. This might allow equipment vendors to select or predefine the most convenient oil mist inlet and vent locations.

Two final points deserve to be reemphasized:

• Many bearings fail because unclean containers contaminate the lube oil as it is being transferred from storage drums to pump bearing housings. Reliability- focused equipment users will only use properly designed plastic containers for their lube replenishing and oil transfer tasks. Each of these containers will cost only a fraction of the cost of a single bearing failure. This is one product for which the payback has occasionally been measured in mere days.
• Some plants make bearing procurement and storage decisions only on the basis of initial cost and schedule. This is inconsistent with a reliability focus. Proper storage and asset preservation are of great importance to plant reliability and profitability. Neglecting these issues is certain to deprive a facility of ranking among Best-of-Class producers.

References

1. Bloch, Heinz P. & Alan Budris, Pump User's Handbook: Life Extension, 2nd Edition, Fairmont Publishing Co., Lilburn, GA, 2006
2. Bloch, Heinz P. & Abdus Shammim, Oil Mist Lubrication: Practical Applications, Fairmont Publishing Co., Lilburn, GA, 1998
3. Bloch, Heinz P., Practical Lubrication for Industrial Facilities, Fairmont Publishing Co., Lilburn, GA, 2000

Over 70% of equipment failures can be attributed to contamination. The best course of action is to minimize the introduction of contaminants. It is estimated that the cost to remove contaminants is 5 to 10 times the cost to keep them out in the first place. Thus, any World-Class lubrication program begins with good storage and handling practices and the minimization of ingressed contaminants from the environment through effective seals, desiccant breathers and other practices.

ISO Cleanliness Code 
Before cleanliness standards can be established, one has to understand how cleanliness is measured. Most common methods today measure amount and size of particles with an optical particle counter. As fluids move past a laser light, particles in the path block the light and create a shadow that is measured by a photo sensor. The sensor, which has been calibrated with a test dust, reports the number of particles by size per ml.

Dark fluids and water contamination will not give good results with an optical particle counter. With these fluids, methods such as direct counting of particles on a patch through a microscope are used. Another method for counting particles in solutions and dark liquids is pore blockage, which equates particles and size by flow decay through a sensor screen of certain size pores (like 10 micron, for example). This technique will give different results than an optical particle counter, but it can be used on certain fluids as a good trending device. (Note: Cleanliness standards discussed in this article will focus on optical particle count numbers.)

Prior to 2000, optical particle counters were calibrated with AC Fine Test Dust (ACFTD). Although a new calibration technique with a Medium Test Dust (MTD) that was traceable by National Institute of Standards and Technology (NIST) was established and approved in December 1999, it gave a major difference in the calibration. There is a signifi- cant difference between the two calibrations in particle size distribution as measured by an electron microscope. For example, there were significantly more particles below 10 micron with the NIST calibration versus ACFTD. In order to keep the same ISO Cleanliness Table, measured particle sizes were adjusted to reflect this difference. Previously the size ranges reported by ACFTD were ≥ 2μm, ≥ 5μm and ≥ 15μm. The new method reports ≥ 4μm[c], ≥ 6μm[c] and ≥ 14μm[c]. The letter "c" after the code indicates that the calibration was based on the NIST method. Today, most oil analysis laboratories have converted to the NIST method and use the three number designations.

Equipment cleanliness standards are established by use of ISO 4406 illustrated in Table I.

The ISO cleanliness code is reflected as a three-number designation: = 4µm[c], = 6µm[c] and = 14µm[c]. Notice that for every increase of one ISO range number the number of particles doubles. This is very significant since very small increases in the ISO range particle number can result in very large increases in the actual number of particles. Remembering one range number such as 11 (which is 10 to 20 particles) allows you to construct a table by doubling the numbers for every increase in range number. The following example on how to convert particle sizes and amounts to the three-number cleanliness designation is shown in Table II. Assume the following particle sizes and amounts were measured with an optical counter.

Let's look at an example of how much dirt can pass through a system. Consider a fluid being pumped at 65 gpm that has an ISO cleanliness code of 22/21/18 (which is typical of new unfiltered hydraulic oil). In one year, 8800 lbs of dirt would pass through this pumping system. How long do you think a pump would last in that environment? If the fluid is cleaned to a 16/14/11 (which is the typical fluid cleanliness required in a hydraulic system), only 9 lbs of dirt would pass through the pump in one year. A six ISO code change resulted in a 1000-fold increase in particulate contamination. From this example, we can clearly see that even small changes in the ISO cleanliness rating results in large change in particulate contaminants.

Filtration basics
Once the ISO cleanliness number has been established for a particular equipment type, the fluid needs to be cleaned to achieve that target through filtration. As noted in the opening sidebar, subsequent articles in this series will discuss how to set the cleanliness targets and filtration systems to achieve these targets. In the remainder of this article, however, we will be introducing basic filtration principles.

Fig. 1 illustrates the two major filter categories—surface filters and depth filters.

Surface filters are not particularly effective in systems with low-solid and large contaminants. They are usually made of woven wire or pleated paper with a consistent pore size that provides the fluid with a straight path.

Depth filters make it more difficult for a particle to pass through, thus they provides better filtration than surface filters. Depth filters incorporate cellulose, metal or glass fibers that are stacked to provide media height. Both glass and metal can have a graded (tapered) density in pore size to provide greater and more effective filter utilization. The use of finer fibers has resulted in major advances in filtration technology. Each fiber type provides different performance characteristics.

Filters can be rated either "Nominal" or "Absolute."

• The Nominal rating is normally used with paper filters. It is an arbitrary rating assigned by the manufacturer as to the largest particle that will pass through the filter (for example, a 10-micron nominal filter). These filters typically will only remove 50% of the particles in their size range. Since this rating is not based on actual laboratory data, it is not very useful in establishing equipment cleanliness standards.
• The Absolute rating of a filter means that laboratory data was provided in the filter rating through the ISO 16889 Multi-Pass Filter Test shown in Fig 2. This test is used in filter development to measure the performance properties of different filters under laboratory conditions. It is used to calculate the Beta Ratio (as illustrated by Fig. 3) as follows:

Assume we are evaluating the filter in Fig. 3 on its ability to remove particles >10 microns and 400 particles in this size range enter the filter and two particles >10 microns pass through it.

The ISO 16889 Multi-Pass Test is conducted as follows:

• Optical particle counters are installed both upstream and downstream of the filter to measure the number of certain sized particles entering and passing through the test filter. Circle 72 or visit www.LMTfreeinfo.com Fig. 2. The ISO 16889 Multi-Pass Filter Test (Source: HY-PRO Filtration)
• NIST test dust is injected into a circulating fluid at an average rate of 3mg/l to 10mg/ml. Rates are varied by different filter manufacturers. A low-viscosity test fluid is circulated at 15-30 gpm.
• All particles and their sizes are measured before and after the filter. Flow continues until the terminal pressure drop of the filter is reached, which varies by different filter manufacturers, and ranges from 60-100 psid. The terminal pressure drop is defined as when the OEM says this is the maximum drop across the filter before it is changed.
• A Beta Ratio is calculated at every 10% of the terminal pressure drop and a weighted Beta Ratio is reported as the final result.
• Dirt Holding Capacity, another important factor in filter performance, is calculated as the total amount of test dust the filter retained during the total run.
• In order to better simulate actual field conditions, some filter manufacturers vary the flow rates during the test run.

Some filter manufacturers have varied the multi-pass test by varying the flow rate to more closely simulate actual hydraulic conditions. The efficiency of a filter is calculated as follows:

β - 1/β x 100

A filter with a Beta Ratio of 200 has an efficiency of 99.5%, while a filter with a Beta Ratio of 1000 has an efficiency of 99.9% This doesn't sound like much of an increase for a five-fold increase in Beta Ratio, but with the large number of particles in most systems it can have a large effect on the ISO Cleanliness Rating.

The term today for the absolute rating of a filter refers to a Beta Ratio of at least 200 and filter manufacturers are moving to 1000. In the past, a filter was considered absolute if its Beta Ratio was 75. Today the most important factor in a filter's performance is not its absolute rating, but how it performs in attaining a certain ISO Cleanliness Code.

Conclusion
Fluid cleanliness is vital in achieving equipment reliability and filtration is a key component in achieving cleanliness goals. Understanding basic filtration concepts is necessary in making decisions on how to achieve system cleanliness. The next article in this series will discuss setting and attaining cleanliness targets with filtration.

Acknowledgements 
The author wishes to thank Mike Boyd of Fluid Solutions and Aaron Hoeg of HY-PRO Filtration for their assistance in the preparation of this article.

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLECertified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526. LMT

A well-designed lubrication procedure must address three separate and distinct issues. Specifi cally, each bearing must receive the correct type of lubrication in the proper amount at the right time. If any one of these three factors is overlooked or approached incorrectly, the lubrication procedure has failed, and, as a result, the bearing will fail prematurely.

Type of lubrication…
Any Maintenance Manager worth his or her salt will be able to identify most or all of the offi cial lubricants on the plant site. Still, the authorized list of lubricants is only part of your maintenance reality. Most management-sanctioned lubricant lists contain redundant and unnecessary choices due to years of supplier and vendor recommendations combined with the preferences of your maintenance personnel. Additionally, a quick walk through the shop or lube room will, in all likelihood, lead you to discover a great deal more variety in lubricants than you thought you were using. And, if you check a few lockers and tool boxes, you will fi nd even more. Obsolete or out-of-date lubricants, unmarked oils, and unfamiliar and unapproved brands and types—if you fi nd any of these (and you will) your lubrication program is out of control.

As a general rule, the fewer lubricants it takes to sustain a manufacturing process, the better that process is. In other words, the fewer choices your millwrights and lube techs have, the fewer incorrect choices they can make.

It is important to reduce the number of lubricants to the lowest common denominator. Brand names and personal preferences do not matter. The only factors to consider in this selection are the properties of the lubricants and the specifi cations of the bearings that they are to lubricate. Ideally, you should strive to get down to two or three types of grease, one or two types of hydraulic oil, and no more than three types of other oils for your entire process. As a suggestion, have your Maintenance Planner or Reliability Engineer discuss this goal of lubricant consolidation with your lubrication vendor’s factory representatives, as well as with your bearing supplier’s fi eld engineers. Let these professionals be your experts.

Amount of lubrication…
At this moment somewhere in your mill or factory, there is a bearing running hot due to over-lubrication. Also at this moment, there is another bearing in your process running hot due to under-lubrication. Which of these conditions is worse—and which bearing will fail fi rst? The fact is that both conditions are equally as bad, since both are indications of a failed maintenance effort. Moreover, one is just as likely to occur as the other. That said, either condition will cause your process(s) to literally grind to a halt. The key to your maintenance success is to determine the maximum and minimum amounts of lubricant that you must maintain at each application, and then to design your lubrication procedures around those two fi xed points. As a fi rst step to controlling the amounts of lubrication applied to bearings, you will need to calibrate all of the grease guns in your plant. Since the lubrication procedures for bearings should be written in terms of how many shots of grease to apply, it is important to both defi ne and control how much grease is contained in a “shot.” Consistency between grease guns is the goal of calibration. It is important that all of your dispensing devices are applying the same amount of grease when your technician pulls the handle.

It also is important to thoroughly clean the guns inside and out to control contamination—and to discard any that are in poor condition. Each reconditioned and calibrated grease gun should be marked with the date before being placed back in service. You should set up a general PM in your CMMS to perform this function at least twice per year. (The calibration procedure is straightforward. For details, refer to the accompanying sidebar.)

Lubrication interval… 
It is the nature of lubricants that they use themselves up as they do their job. Thus, they must be replenished. If this replenishment occurs at the proper intervals, then the moving parts continue to move within specifi cations. But if the interval is not correct, if it is too long or not long enough, then over-lubrication or under-lubrication will be the result. Both conditions are the fi rst phases in the sequence of events that lead to machine failure.

The most accurate method available for determining lube interval is the predictive technology known as vibration analysis. If this methodology is not available or practical at your site, the OEM recommendations supplied with each bearing will be suffi cient to use as your beginning lubrication interval, provided you are not exceeding the bearing manufacturer’s specifi cations and ratings in your application.

Please note that if you are running your process in excess of its rated capacity, you will need to monitor your components with vibration analysis or thermal technology so that you can determine the point at which the component needs re-lubrication, even if you must hire an outside contractor to perform these analyses.

Developing your lube procedure 
As with any PM procedure, the lubrication procedure should be developed and written up with a specifi c machine in mind. Once you have developed the procedure for one machine, extrapolate the steps to include other machines in your process.

Identify all of the lube points at the machine center. This step should be done in the fi eld by the individual who ultimately will be responsible for lubricating the machine. This individual will locate the zerks and lube points on the machineand will call them out to the Maintenance Planner, who will document the locations. Each lube point should be wiped, inspected and marked with a black or yellow paint pen so that they will be easy to locate.

As the bearings are inspected, the Planner should make notations of any that have blown seals or that show other evidence of damage or failure. The bearings in question should be scheduled for replacement as soon as it is practical to do so. Any broken or defective grease zerks should be replaced at this time. Once the zerks have been located and cleaned, they should be covered to prevent contamination from entering the bearing or component. Push-on covers can be purchased for this purpose, or the tried-and-true method of putting a fresh daub of clean grease on the zerk can be used.

Once the lube point identifi cation has been completed, compare the Planner’s notes to the machine’s drawings and manuals. The last thing that seems to be on engineers’ minds when they are designing machinery is the accessibility of lube points. Thus, it is entirely possible that there are lube points on your machine that have never received any grease at all. If this is the case, now is the time to rectify the problem. Identify any bearings that have been overlooked at this step.

Bearing by bearing, calculate the manufacturer’s recommended lubrication intervals and amounts. A good tool to use when performing these computations can be found at the following web address: www.skf.com/skf/productcatalogue/jsp/calculation/ calculationIndex.jsp?&maincatalogue=1&lang=en. Be sure to convert your answer to “shots.”

Bearing by bearing, write the procedure. Start at one end of the machine and take the bearings in order. Beside each bearing that you list on the lube document, leave a space for the technician’s initial, the number of shots applied and the date.

Lubrication technicians must be trained in the proper methodology before being allowed to perform their work. As an introduction to their training, make them aware that the vast majority of bearing failures are the result of over-lubrication. Be certain that they are equipped with fresh grease, clean rags and a pocketful of replacement zerks when they go out into the fi eld. It is extremely important to build accountability into this training. Lubrication techs are not just grease monkeys. Their work may, in fact, be the most important maintenance function in the plant.

Once you have performed your lubrication procedure, you must monitor the results. The most effi cient way to do this is with thermal technology. After the freshly-lubricated bearings have run for an hour or two, check them with a thermal camera. Any that are running hot have been over-lubed. If you determine that this condition is due to a lubrication error by your technician, retrain the individual and document the training. If you feel that the work was done as requested, then you will need to adjust the text of your lube PM accordingly.

Follow up 
As with most other maintenance functions, a lubrication PM is a living document. Each time your technicians perform such a procedure, follow up their work by checking the results. This fi nal important “step” is vital in the enhancement of your entire maintenance effort.

Ray Atkins, CPMM, CMRP, is a veteran maintenance professional with 14 years experience in the lumber industry. He is based in Rome, GA, where he spent the last five years as maintenance superintendent at Temple- Inland’s Rome Lumber facility. He can be reached at raymondlatkins@aol.com

Defining synthetic lubricants In general, the synthetic designation applies to products whose basestocks have been manufactured as opposed to being extracted from naturally occurring petroleum. Synthetic lubricants are different from conventional petroleumbased oils because their molecular structures are custom designed and tailored to meet specific performance criteria.

Most petroleum-based and synthetic lubricants consist of a basestock and various additives selected to improve or supplement the lubricant's performance. The basestock is the primary component—usually 70% to 90%—of the finished lubricant. Its structure and stability determines the flow characteristics of the oil, as well as its temperature range, volatility, lubricity and cleanliness. Since the basestock is the dominant component, one way to make a better lubricant is to start with a better basestock.

Basestock categories
The following list highlights the various types of basestocks used to formulate synthetic lubricants along with their principal applications.

• Polyalphaolefins and dialkylated benzenes provide performance similar to mineral oils and are compatible with them. They are used as hydraulic fluids and gear, bearing lubricants and compressor lubricants.
• Dibasic acid and polyol esters readily accept additives, which make them excellent compressor lubricants.
• Polyglycols are used primarily for lubricating gears and bearings.
• Phosphate esters provide fire resistance. Silicones are nontoxic, fire resistant and water repellant.

Additives enhance basestock properties or add new ones, such as improved stability at high and low temperatures, modified flow properties and reduced wear, friction and corrosion. Basestocks and additives must be selected carefully and balanced to allow the finished lubricant to do its job—which includes protecting moving parts from wear, removing heat and dirt, preventing rust and corrosion, improving energy efficiency and extending lubricant life. Synthetic lubricants can provide economic advantages when used in place of petroleum-based lubricants. These benefits include:

• Improved energy efficiency
• Wider operating temperature range
• Increased performance ratings
• Reduced maintenance
• Better reliability and safer performance

For best results, users should consult with the manufacturer prior to selecting synthetic lubricants. While they have outstanding performance characteristics, the proper choices must be made to ensure that the right product is chosen for any given application.

Joe Foszcz is a contributing editor to Lubrication Management & Technology. For more information, e-mail him directly: jfoz@atpnetwork.com

2 Technologies has rolled out its new Mobility Series of Fourier Transform Infrared (FT-IR) spectrometers. Developed for use in the field, these rugged, selfcontained units are purpose-built to move FT-IR spectroscopy out of the conventional analytical laboratory and closer to the source of the sample. That means anywhere in the world.

Consisting of three systems, the MLp, the ML and the MLx, the intuitive Mobility series has been designed to survive in rugged environments and be operated with little to no training by the user. According to the manufacturer, this level of durability and simplicity of use makes these products ideal real-time process monitoring tools for lubrication condition monitoring and a variety of petrochemical, food and mining applications. With their ability to deliver accurate and precise information efficiently from even the most remote places on the planet, the three analyzers in the Mobility Series are powerful tools in the alleviation of problems associated with sample throughput and the minimization of bottlenecks.

Extending the capabilities of FT-IR technology 
Featuring an intuitive operating system and straightforward sample interface, spectrometers in the Mobility Series render traditional time-consuming sample preparation and transfer to and from a conventional lab obsolete. Users immediately obtain the type of actionable information that lets them make critical decisions on the spot. These spectrometers incorporate two new diamond-based sampling systems, one utilizing the principle of internal reflection and the other featuring a completely new type of transmission cell. Between these two systems, a broad range of liquids, solids, oils, gels and pastes can be easily and precisely analyzed.

A2 Technologies
Danbury, CT

Improved equipment operation and energy savings are two welcome benefits associated with the selection of the correct synthetic for the job.

All synthetics are not alike. Selection should be based on the optimum base stock type for the application. The additive system, which also is very important, imparts unique properties to the finished synthetic lubricant. As a result, there can be major differences in performance for the same synthetic type from different suppliers. Case histories and actual field tests are the best way to select a particular synthetic fluid. There are many applications where mineral oils, because of their cost and performance, are perfectly acceptable. Synthetics are problem solvers to be used in applications where their unique properties are cost-justified under the following conditions:

• Temperature Extremes—Since synthetics contain no wax they are used at very low temperature conditions. ISO 32 PAO and ISO 32 diesters have pour points > -50 F. They also are effective at temperatures well above 200 F, whereas mineral oils should be limited to a maximum of 200 F and synthetics should be considered at temperatures as low as 180 F.
• Lower Wear—In general, synthetics provide much higher film strength and lubricity than mineral oils, especially in a high-sliding environment that occurs in worm and hypoid gears.
• Energy Savings—Some synthetics have low coefficients of friction because of their uniform molecular structure, resulting in significant energy savings in many applications.

Properties & applications of synthetics

Table I illustrates the most common synthetics and their major applications.

Polyalphaolefins (PAO)…
If only one synthetic could be selected in a plant, it would be a PAO. These are the most versatile and most widely used synthetics. They operate over a very wide temperature range, can be produced in a wide viscosity range without changing their basic properties and are compatible with most other lubricant types. Because of their nonpolarity, they have poor additive solubility and cause slight seal shrinkage. Consequently, they must be blended with a polar synthetic such as an ester, which swells seals and gives good additive solubility.

Some of the more common uses for PAOs include:

• Hot and heavily loaded gear boxes: an EP PAO is used for helical and herringbone gears, while a non-EP ISO 460 is commonly used for worm gears.
• Rotary screw air compressors: PAOs and polyalkylene glycols (PAGs) are the two most commonly used air compressor oils for extended life service.
• ISO 68 PAO is used in oil mist lubrication of rolling element pump and motor bearings.
• PAOs have H1 approval in food plants and are used in a wide range of applications.
• PAOs are not recommended for high-temperature reciprocating compressors because they can form hard deposits on exhaust valves, thus not allowing them to seat properly.

Diesters…
Diesters are one of the oldest synthetic types—and they are limited in the viscosity ranges produced. The most common ISO VGs are 32, 46, 68, 100 and 150. The viscosity indexes are only high for the ISO 32 while the others are in the 70-100 range, depending on the alcohol and acid used in their manufacture.

The major performance strength for diesters is their excellent solvency minimizing deposit formation. They also have good low-temperature properties and high thermal stability and flash point.

Diesters have a low aniline number and a tendency to swell elastomeric seals. Therefore, resistant seals, such as DuPont Viton, need to be used. Diesters also can hydrolyze in a hot, high-moisture environment—something that
occurs in rotary screw air compressors.

Uses for diesters include:

• Major application in severe duty reciprocating air and hydrocarbon compressors: diesters' high thermal stability and excellent solvency will prevent carbon buildup on exhaust valves.
• The synthetic of choice in air compressors many years ago: diesters are still used, but to a limited extent because of their potential for hydrolyzation. They are blended with mineral oils to form partial synthetics used in air compression and with PAGs for air compression.
• Diesters are used extensively both in the ISO 68 and 100 viscosity grades for oil mist lubrication of rolling element pump and motor bearings.

Polyol Esters (POE)…
POEs have very high thermal stability allowing them to be used in a very high temperature environment. They also are fire resistant with high flash- and fire-point temperatures. Because they are readily biodegradable, they can be used as hydraulic fluids in environmentally sensitive areas.

The major disadvantage of POEs is their cost. They are 50% more expensive than PAOs, PAGs and diesters. Although they have a tendency to hydrolyze at hightemperature and high-moisture conditions, POEs are more stable than diesters.

Primary uses for POEs include:

• Aviation and industrial gas turbine applications where the effective operating range is -40 F to 400+ F, with primary viscosity ~27cSt.
• Extended life fluid for air compressors: rated >12,000 hours and stable at temperatures of 240 F, which is higher than the maximum temperature allowable in a rotary screw air compressor.
• Fire-resistant hydraulic fluid for underground mining, steel mills and foundries: Factory Mutual approved and MSHA certified; flash point for ISO VG 46 > 510 F and fire point >680 F.
• Environmentally friendly hydraulic fluids that are readily biodegradable and contain ashless antiwear additives.

Polyalkylene glycols (PAG)…
As discussed in the first article in this series, PAGs are quite versatile. They can be designed to produce a wide variation in water solubility by adjusting the ratio of ethylene and propylene oxide during manufacturing. They have very high viscosity indexes exceeding 250, as well as excellent polarity for metal surfaces that gives them good lubricity. PAGS don't produce deposits and can be designed to minimize hydrocarbon gas solubility. Their major weakness is compatibility with hydrocarbon lubricants like mineral oils and PAOs. They also shrink many elastomeric seals and attack certain paint types.

Some primary uses for PAGs include:

• Rotary screw and centrifugal air compressors
• Enclosed gear boxes in particular worm gears
• Fire-resistant hydraulic fluids
• Food grade products ISO VG 150 and higher needing H1 approval
• Hydrocarbon-flooded rotary screw compressors
• High-pressure ethylene compressors in HDPE production

Applications
This following list highlights several applications where synthetics provide major cost justifications. Many more applications could have been presented:

• Air Compressors
  • Rotary Screw
  • Reciprocating
• Hydrocarbon Compressors
  • Rotary Screw
  • Reciprocating
• Enclosed Gear Boxes
  • Helical, Herringbone, and Spiral Bevel
  • Worm

Air compression
Rotary screw compressors…
Most of today's industrial air compressors are rotary screws like that shown in Fig. 1.

In a rotary screw compressor, air is compressed, high temperatures are generated and, along with the moisture that is present, a severe oxidative environment is present for oil. The lubricant in this equipment performs four major functions: cooling, lubricating (bearings, gears and screws), sealing and corrosion prevention. This requires an oxidatively stable lubricant with high VI and good lubricity. Many OEMs have their own fluids—which are mainly synthetics. As shown in Table II, the different lubricants used can be classified based on fluid life.

The expected hours shown in Table II are OEM recommendations on expected life. Depending on the conditions, synthetics may exceed these numbers if the temperature and moisture are lower than normal.

The most common fluids used for air compressors for extended service are ISO VG 46 PAO and PAG/Ester. The esters most commonly used with PAGs are diesters and POEs that swell seals to counteract shrinkage caused by PAG.

POE gives the longest life extension for the fluid and is being used for extendedwarranty applications. Some POEs on the RPVOT test, which is a measure of the oxidative stability of a fluid, give results in excess of 3000 minutes—that's nearly double the results obtained with PAOs and PAGs. POEs can be used at temperatures up to 240+ F, which is above the shutdown temperature of an air compressor. PAO can handle temperatures up to 220 F and PAGs are lower at 200 F. PAGs have the added advantage of very high viscosity indexes that gives a thicker film at high temperatures which minimizes wear. Furthermore, they don't form deposits at high temperatures when they oxidize.

Two major cost justification areas for the use of synthetics is in fluid life extension and energy savings. Consider the following case study.

An evaluation was performed on a 300 hp compressor with a 60-gal. sump capacity operating at 180 F. Running mineral oil required change-out every 1000 hours, while a PAO greatly exceeded the OEM recommendation of an 8000-hour change by running 15,000 hours. This resulted in a 67% savings—or more than $1700—in lubricant costs in one year. (Data courtesy of Dr. Ken Hope, Chevron Phillips.)

Energy savings can be significant with air compressors. A number of studies have shown savings between 3-5% with rotary screw compressors. Combining energy savings and longer fluid life, along with less wear and better operation, synthetics make sense for air compression applications.

Reciprocating…
While reciprocating compressors (Fig. 2) are not used much in air compression today, there are still many old compressors working in the industry.

Because of high temperatures, the cylinder region in a reciprocating compressor is the most difficult area to lubricate. One major problem associated with the use of mineral oils for this application is that they form hard deposits when they oxidize and coat the exhaust valves, thus keeping the valves from seating properly. As a result, hot gas is drawn back into the cylinder to be recompressed. This dangerous condition can lead to high heat generation and a possible fire.

The lubricant of choice for reciprocating compressor applications is an ISO 100 or 150 diester with excellent solvency. Fig. 3 shows two actual exhaust valves. The valve on the left had been running for six months on diester. The valve on the right had been running four months on mineral oil. The valve on diester continued to run with no coking, saving over $10,000 in valve replacement costs.

Hydrocarbon compression Rotary screw compressors…
Non-flooded rotary screw compressors running at temperatures below 180 F can use mineral oils without major problems. Users, however, may want to turn to a synthetic like a diester or a PAO for their energy-saving potential. Flooded screw compressors with hydrocarbon gas will quickly lose their viscosity with most mineral oils and synthetics because the gas dissolves in the lubricant, thus lowering the viscosity.

PAGs are the most resistant lubricant to hydrocarbon gas dilution and are recommended for flooded screw compressors. More resistant to dilution than mineral oils, PAGs will, however, be diluted to an extent with hydrocarbon gases, a fact that must be taken into consideration in selecting the initial viscosity to arrive at the correct viscosity at the operating temperature. PAGs have the added advantage of having very high VIs.

Ethylene high-pressure reciprocating compressors…
PAGs are the lubricant of choice for high-pressure ethylene compressors because of their minimal dilution by hydrocarbon gas. The typical viscosity of PAGs used in this application is 270 cSt. The film integrity at a reasonable viscosity is maintained at very high pressures, leading to low lubricant consumption and very low wear rates.

Low-pressure hydrocarbon compressors…
Mineral oils at ISO VG at moderate temperatures have been used successfully. As conditions become more severe, though, synthetics need to be considered. Both PAGs and diesters are good alternatives. PAOs, however, are not recommended because of their tendency to form hard deposits when they oxidize.

Enclosed gearboxes Helical, herringbone and spiral bevel…
Gearboxes experience EHL lubrication through sliding and rolling motion. A key criterion in lubricating gear teeth is to have thick enough film for the high sliding and shock loads. In many cases, EP additives are effective as anti-scuffing agents and are used in many loaded gear reducers. Parallel and right angle shaft gears such as helical, herringbone and spiral bevel are lubricated normally with an ISO VG 220 with EP. Under abnormal conditions, such as high temperatures and high shock loads, an ISO VG PAO with EP is used. Although PAGs can be used, because of their incompatibility problems, PAOs are preferred. Energy savings are more difficult to attain with high-efficiency gears like helicals, herringbones and spiral bevels. Normally, synthetics have shown efficiency improvements of 3% or less. Therefore, the use of synthetics for these gears is not justified by energy savings alone. A better way to justify in these applications is to take into account how dramatically gear performance is improved under difficult load or temperature conditions when synthetics are used.

Worm…
Worm gears (Fig. 4) are highly inefficient. They also are good candidates for synthetics. A worm gear is a right-angle gear with non-intersecting shafts. These units consist of a steel worm and a sacrificial bronze wheel. There is very little rolling motion. Most motion is sliding—which causes the high wear and high heat. Worm gears typically can run 90 F degrees or higher than ambient temperatures. Since EP additives can attack bronze, very few EP gear oils had been used in the past. The only alternative had been to use a compounded high-viscosity mineral gear oil—such as ISO 460—containing animal fat for lubricity to protect the teeth during boundary lubrication. These types of lubricants oxidized quickly at high temperatures and didn't provide a high level of wear protection.

The two most popular synthetics used in worm applications today are ISO VG 460 PAO and PAG. Each will perform very well. Neither of these synthetics contain EP and they both provide a high film strength and score very high on the FZG test that measures scuffing of gear teeth at different load stages. Mobil SHC 634, which is an ISO 460 PAO with no EP, exceeds 13 stages, the highest level on the test. This results in very low wear rates and energy savings.

Efficiency savings in excess of 7% have been documented. Because of their lower traction coefficient (which is the internal friction in the lubricant) PAGs often provide higher efficiency savings—but PAOs do very well. Temperature drops with a synthetic can be 20-30 F degrees. While PAGs are more common in gearboxes in Europe, more are being used in the United States. A PAG, because of its greater energy efficiency, is a good choice for new gears and can be used on other gears only with the proper flushing procedures. Moreover, PAGs attack some paints. A safer choice to convert a worm gear from mineral to synthetic is to use a PAO.

The following is a case history of the conversion from mineral oil to PAO:

A major can manufacturer used double-enveloping worm gears with an average reduction ratio of 60:1. The company was using a compounded ISO 460 mineral oil. On average, the company was experiencing four gear failures per year, each costing an average of $12,500 to repair. Temperatures typically were 200 F—and in some cases got as high as 215 F. The mineral oil was replaced with an ISO 460 PAO and the failures were eliminated. In fact, to date, 18 months later, there still have been no failures in this equipment. In addition, the average temperature dropped across the worm gears by more than 20 F degrees.

Conclusion
Synthetics are real problem solvers. While they can work well and be cost justified, there are many applications where mineral oils will do just as well. Three applications where synthetics can improve equipment operation and provide major cost savings are air compressors, high-pressure and hot reciprocating compressors and worm gears.

Deciding which synthetic to use is very important. Each candidate will have advantages and disadvantages that need to be considered before a final decision is made.

Keep in mind that the same synthetic type from different manufacturers can give different results. Even though the base stocks may be similar, the additive package may impart different properties from one supplier to another. Make comparisons between the data sheets, but let your final decision rest on field performance. Look at case histories and, if possible, run a carefully controlled plant test where meaningful data can be collected. Even though this will not be possible in some cases, definite equipment improvements can still be observed without rigorous testing and data collection. Be sure to document this data. Since synthetics are more expensive than mineral-based oils, you will want to be very accurate in your cost justifications.

Acknowledgements
The author wishes to thank Tim Taylor of Summit and Dr. Martin Greaves of Dow Chemical for their assistance in the preparation of this article. LMT

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLE-Certified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526.

Ken Bannister, Contributing Editor

Seven years earlier, James Watt had successfully delivered the world's fi rst viable steam engine capable of powering an entire factory of machines. Improving on the crude design of the original Savery-Newcomen engine used primarily to draw water, Watt's design converted reciprocating motion into rotary motion. The rotary motion of the driven shaft could now be slaved into driving multiple line shafts simultaneously. Fourteen years later, in 1783, North England inventor James Arkwright was credited as the fi rst industrialist to use a Watt steam engine to power his entire textile mill.

The rotary motion of crank bearings and leatherbelt- driven line shafts introduced a constant need for lubrication. Petroleum-based lubricating oils as we know them today would not be discovered for another 70+ years, requiring the use of animal/ vegetable based lubricants such as olive oil for the rotary bearings and tallow (animal grease derived from cattle and sheep) for the drive belts.

The drawback with animal/vegetable oils is their lack of chemical inertness that results in acid formation after short periods of use, requiring constant cleaning and reapplication of lubricant. This important job became the responsibility of children. Because of their small stature and dexterity, they were able to scurry around quickly on all fours, on severely height-restricted fabricated gantries above the line shafts, applying lubricant as and when required.

Countless youngsters worked 18-20 hours per day in appalling conditions—and many of them were maimed and killed in the lubrication process. These little children, scampering across the gantries in a stooped manner, were said to resemble monkeys, which is how the term "grease monkey" is thought to have originated.

While children no longer take care of the lubrication in our facilties, have times really changed? Today, as I work with companies to implement engineered lubrication management programs, I am constantly amazed by the number of organizations that still treat lubrication as a "necessary evil," and their lubrication personnel as second-class citizens, referring to them as "grease monkeys," "grease jockeys" and "oilers." Many have low expectations for their lubrication personnel, providing little or no training for the job, using the position as preretirement staging positions, etc. Sound familiar?

I submit that it's time to lead an independent charge of our own to elevate the status of lubrication in the minds of all industrial personnel!

Although we may not be able to strike a unilateral declaration of independence, we all can work toward seriously legitimizing the science of lubrication in the minds of our co-workers. This can be achieved by taking responsibility for reducing machine downtime and reducing energy costs through the use of improved lubricants and lubrication practices. We also need to implement defi ned roles and responsibilities for all lubrication personnel, insist on quality training and accreditation for them and strongly support their being recognized as an integral part of an equipment reliability program/initiative/approach/team.

Are you and your company ready to take on this challenge? Good Luck!

Ken Bannister is lead partner & principal consultant for Engtech Industries, Inc. Phone: (519) 469-9173; e-mail: kbannister@engtechindustries.com

MULLER RECEIVES ASHRAE'S DISTINGUISHED SERVICE AWARD
Purafi l's technical director, Chris Muller, has been honored with the ASHRAE Distinguished Service Award. A 12-year ASHRAE member, Muller serves as a Distinguished Lecturer for the organization and as chair of its Standard Committee 145P, which was charged with the task of engineering the ASHRAE Standard 62.1. He remains thoroughly involved within the organization as a voting member of several committees and as a co-author of the ASHRAE Standard 62.1-2004 User's Manual.

GE MOVING SOME GAS TURBINE OPS TO HUNGARY
In response to growing international demand, GE Energy has announced the decision to add capacity for its 50-Hertz LM6000 aeroderivative gas turbines to a GE manufacturing facility located in Veresegyhaz, Hungary.

"We are shipping more and more LM6000 units to customers throughout Europe, Asia and the Middle East. By utilizing the Hungary facility, we can provide our international customers with more localized service and support," said Charles (Chip) Blankenship, general manager of GE Energy's aeroderivative division. According to Blankenship, this move will free up resources at the company's Houston, TX, facility to better accommodate increasing demand for the LMS100.

The operations in Hungary, located approximately 20 kilometers outside of Budapest, have been in operation since 2001 supporting the build and repair of the corporation's heavy-duty gas turbines. Packaging and testing for both the SAC and DLE models of the 50-Hertz LM6000 can now be completed there. GE Energy's aeroderivative division is the world's largest service provider for this type of gas turbine technology.

ASSOCIATION NEWS

PUMP SYSTEMS MATTER ANNOUNCES 4 NEW SPONSORS
Pump Systems Matter™ (PSM), a North American educational organization aimed at lowering energy needs by optimizing pump system performance, has announced four new sponsor organizations: Hydro Inc., Engineered Software, Inc., Manitoba Hydro and Xcel Energy. PSM was launched to help assist pump users gain a more competitive business advantage through strategic, broad-based energy management and pump system performance optimization. Its initial development was led by the Hydraulic Institute (HI). Incorporated as a new 501(c) 3 educational organization in 2006, PSM currently is seeking sponsors and board members that can actively contribute to its growth. Membership is open to utilities, market transformation organizations, government agencies, pump users, contractors, consultants, engineering fi rms, trade and professional associations, as well as North American pump manufacturers and suppliers of motors, drives, seals, couplings, bearings, housings, instrumentation and control systems and pump specifi c software. For more information, contact Joananne Bachmann at (973) 267-9700 x 22 or via JBachmann@pumps.org.

NEW EXECUTIVE DIRECTOR NAMED FOR PTDA FOUNDATION
The Power Transmission Distributors Association (PTDA) Foundation has announced the appointment of Phyllis Russell to executive director. In her new role, Russell will be responsible for all aspects of the Foundation's management. Charged with implementing the Foundation's missions, goals and objectives, she will oversee fundraising and relationship development in support of the organization's major workforce development initiative, the Industrial Careers Pathway® (ICP).

SMRP OPENS LOUISVILLE CONFERENCE REGISTRATION
This year's SMRP Fall Classic conference takes place October 7-10, 2007 in Louisville, KY, and registration is now open. To take advantage of the Early Bird Registration Fee of $825, you'll need to register by August 26. For more information, visit www.SMRP.org. Remember, to register online, SMRP members must use their membership ID number. Plan now. Don't miss this opportunity for "Building Your All-Star Team with the SMRP Body of Knowledge."

• Temperature Extremes—Since synthetics contain no wax they are used at very low temperature conditions. ISO 32 PAO and ISO 32 diesters have pour points > -50 F. They also are effective at temperatures well above 200 F, whereas mineral oils should be limited to a maximum of 200 F and synthetics should be considered at temperatures as low as 180 F.
• Lower Wear—In general, synthetics provide much higher film strength and lubricity than mineral oils, especially in a high-sliding environment that occurs in worm and hypoid gears.
• Energy Savings—Some synthetics have low coefficients of friction because of their uniform molecular structure, resulting in significant energy savings in many applications.

Properties & applications of synthetics 

Table I illustrates the most common synthetics and their major applications.

Polyalphaolefins (PAO)… 
If only one synthetic could be selected in a plant, it would be a PAO. These are the most versatile and most widely used synthetics. They operate over a very wide temperature range, can be produced in a wide viscosity range without changing their basic properties and are compatible with most other lubricant types. Because of their nonpolarity, they have poor additive solubility and cause slight seal shrinkage. Consequently, they must be blended with a polar synthetic such as an ester, which swells seals and gives good additive solubility.

Some of the more common uses for PAOs include:

• Hot and heavily loaded gear boxes: an EP PAO is used for helical and herringbone gears, while a non-EP ISO 460 is commonly used for worm gears.
• Rotary screw air compressors: PAOs and polyalkylene glycols (PAGs) are the two most commonly used air compressor oils for extended life service.
• ISO 68 PAO is used in oil mist lubrication of rolling element pump and motor bearings.
• PAOs have H1 approval in food plants and are used in a wide range of applications.
• PAOs are not recommended for high-temperature reciprocating compressors because they can form hard deposits on exhaust valves, thus not allowing them to seat properly.

Diesters…
Diesters are one of the oldest synthetic types—and they are limited in the viscosity ranges produced. The most common ISO VGs are 32, 46, 68, 100 and 150. The viscosity indexes are only high for the ISO 32 while the others are in the 70- 100 range, depending on the alcohol and acid used in their manufacture.

The major performance strength for diesters is their excellent solvency minimizing deposit formation. They also have good low-temperature properties and high thermal stability and flash point.

Diesters have a low aniline number and a tendency to swell elastomeric seals. Therefore, resistant seals, such as DuPont Viton, need to be used. Diesters also can hydrolyze in a hot, high-moisture environment—something that
occurs in rotary screw air compressors.

Uses for diesters include:

• Major application in severe duty reciprocating air and hydrocarbon compressors: diesters' high thermal stability and excellent solvency will prevent carbon buildup on exhaust valves.
• The synthetic of choice in air compressors many years ago: diesters are still used, but to a limited extent because of their potential for hydrolyzation. They are blended with mineral oils to form partial synthetics used in air compression and with PAGs for air compression.
• Diesters are used extensively both in the ISO 68 and 100 viscosity grades for oil mist lubrication of rolling element pump and motor bearings.

Polyol Esters (POE)… 
POEs have very high thermal stability allowing them to be used in a very high temperature environment. They also are fire resistant with high flash- and fire-point temperatures. Because they are readily biodegradable, they can be used as hydraulic fluids in environmentally sensitive areas.

The major disadvantage of POEs is their cost. They are 50% more expensive than PAOs, PAGs and diesters. Although they have a tendency to hydrolyze at hightemperature and high-moisture conditions, POEs are more stable than diesters.

Primary uses for POEs include:

• Aviation and industrial gas turbine applications where the effective operating range is -40 F to 400+ F, with primary viscosity ~27cSt.
• Extended life fluid for air compressors: rated >12,000 hours and stable at temperatures of 240 F, which is higher than the maximum temperature allowable in a rotary screw air compressor.
• Fire-resistant hydraulic fluid for underground mining, steel mills and foundries: Factory Mutual approved and MSHA certified; flash point for ISO VG 46 > 510 F and fire point >680 F.
• Environmentally friendly hydraulic fluids that are readily biodegradable and contain ashless antiwear additives.

Polyalkylene glycols (PAG)…
As discussed in the first article in this series, PAGs are quite versatile. They can be designed to produce a wide variation in water solubility by adjusting the ratio of ethylene and propylene oxide during manufacturing. They have very high viscosity indexes exceeding 250, as well as excellent polarity for metal surfaces that gives them good lubricity. PAGS don't produce deposits and can be designed to minimize hydrocarbon gas solubility. Their major weakness is compatibility with hydrocarbon lubricants like mineral oils and PAOs. They also shrink many elastomeric seals and attack certain paint types.

Some primary uses for PAGs include:

• Rotary screw and centrifugal air compressors
• Enclosed gear boxes in particular worm gears
• Fire-resistant hydraulic fluids
• Food grade products ISO VG 150 and higher needing H1 approval
• Hydrocarbon-flooded rotary screw compressors
• High-pressure ethylene compressors in HDPE production

Applications 
This following list highlights several applications where synthetics provide major cost justifications. Many more applications could have been presented:

• Air Compressors
  • Rotary Screw
  • Reciprocating
• Hydrocarbon Compressors
  • Rotary Screw
  • Reciprocating
• Enclosed Gear Boxes
  • Helical, Herringbone, and Spiral Bevel
  • Worm

Air compression
Rotary screw compressors… 
Most of today's industrial air compressors are rotary screws like that shown in Fig. 1.

In a rotary screw compressor, air is compressed, high temperatures are generated and, along with the moisture that is present, a severe oxidative environment is present for oil. The lubricant in this equipment performs four major functions: cooling, lubricating (bearings, gears and screws), sealing and corrosion prevention. This requires an oxidatively stable lubricant with high VI and good lubricity. Many OEMs have their own fluids—which are mainly synthetics. As shown in Table II, the different lubricants used can be classified based on fluid life.

The expected hours shown in Table II are OEM recommendations on expected life. Depending on the conditions, synthetics may exceed these numbers if the temperature and moisture are lower than normal.

The most common fluids used for air compressors for extended service are ISO VG 46 PAO and PAG/Ester. The esters most commonly used with PAGs are diesters and POEs that swell seals to counteract shrinkage caused by PAG.

POE gives the longest life extension for the fluid and is being used for extendedwarranty applications. Some POEs on the RPVOT test, which is a measure of the oxidative stability of a fluid, give results in excess of 3000 minutes—that's nearly double the results obtained with PAOs and PAGs. POEs can be used at temperatures up to 240+ F, which is above the shutdown temperature of an air compressor. PAO can handle temperatures up to 220 F and PAGs are lower at 200 F. PAGs have the added advantage of very high viscosity indexes that gives a thicker film at high temperatures which minimizes wear. Furthermore, they don't form deposits at high temperatures when they oxidize.

Two major cost justification areas for the use of synthetics is in fluid life extension and energy savings. Consider the following case study.

An evaluation was performed on a 300 hp compressor with a 60-gal. sump capacity operating at 180 F. Running mineral oil required change-out every 1000 hours, while a PAO greatly exceeded the OEM recommendation of an 8000-hour change by running 15,000 hours. This resulted in a 67% savings—or more than $1700—in lubricant costs in one year. (Data courtesy of Dr. Ken Hope, Chevron Phillips.)

Energy savings can be significant with air compressors. A number of studies have shown savings between 3-5% with rotary screw compressors. Combining energy savings and longer fluid life, along with less wear and better operation, synthetics make sense for air compression applications.

Reciprocating… 
While reciprocating compressors (Fig. 2) are not used much in air compression today, there are still many old compressors working in the industry.

Because of high temperatures, the cylinder region in a reciprocating compressor is the most difficult area to lubricate. One major problem associated with the use of mineral oils for this application is that they form hard deposits when they oxidize and coat the exhaust valves, thus keeping the valves from seating properly. As a result, hot gas is drawn back into the cylinder to be recompressed. This dangerous condition can lead to high heat generation and a possible fire.

The lubricant of choice for reciprocating compressor applications is an ISO 100 or 150 diester with excellent solvency. Fig. 3 shows two actual exhaust valves. The valve on the left had been running for six months on diester. The valve on the right had been running four months on mineral oil. The valve on diester continued to run with no coking, saving over $10,000 in valve replacement costs.

Hydrocarbon compression Rotary screw compressors…
Non-flooded rotary screw compressors running at temperatures below 180 F can use mineral oils without major problems. Users, however, may want to turn to a synthetic like a diester or a PAO for their energy-saving potential. Flooded screw compressors with hydrocarbon gas will quickly lose their viscosity with most mineral oils and synthetics because the gas dissolves in the lubricant, thus lowering the viscosity.

PAGs are the most resistant lubricant to hydrocarbon gas dilution and are recommended for flooded screw compressors. More resistant to dilution than mineral oils, PAGs will, however, be diluted to an extent with hydrocarbon gases, a fact that must be taken into consideration in selecting the initial viscosity to arrive at the correct viscosity at the operating temperature. PAGs have the added advantage of having very high VIs.

Ethylene high-pressure reciprocating compressors…
PAGs are the lubricant of choice for high-pressure ethylene compressors because of their minimal dilution by hydrocarbon gas. The typical viscosity of PAGs used in this application is 270 cSt. The film integrity at a reasonable viscosity is maintained at very high pressures, leading to low lubricant consumption and very low wear rates.

Low-pressure hydrocarbon compressors…
Mineral oils at ISO VG at moderate temperatures have been used successfully. As conditions become more severe, though, synthetics need to be considered. Both PAGs and diesters are good alternatives. PAOs, however, are not recommended because of their tendency to form hard deposits when they oxidize.

Enclosed gearboxes Helical, herringbone and spiral bevel…
Gearboxes experience EHL lubrication through sliding and rolling motion. A key criterion in lubricating gear teeth is to have thick enough film for the high sliding and shock loads. In many cases, EP additives are effective as anti-scuffing agents and are used in many loaded gear reducers. Parallel and right angle shaft gears such as helical, herringbone and spiral bevel are lubricated normally with an ISO VG 220 with EP. Under abnormal conditions, such as high temperatures and high shock loads, an ISO VG PAO with EP is used. Although PAGs can be used, because of their incompatibility problems, PAOs are preferred. Energy savings are more diffi- cult to attain with high-efficiency gears like helicals, herringbones and spiral bevels. Normally, synthetics have shown efficiency improvements of 3% or less. Therefore, the use of synthetics for these gears is not justified by energy savings alone. A better way to justify in these applications is to take into account how dramatically gear performance is improved under difficult load or temperature conditions when synthetics are used.

Worm… 
Worm gears (Fig. 4) are highly inefficient. They also are good candidates for synthetics. A worm gear is a right-angle gear with non-intersecting shafts. These units consist of a steel worm and a sacrificial bronze wheel. There is very little rolling motion. Most motion is sliding—which causes the high wear and high heat. Worm gears typically can run 90 F degrees or higher than ambient temperatures. Since EP additives can attack bronze, very few EP gear oils had been used in the past. The only alternative had been to use a compounded high-viscosity mineral gear oil—such as ISO 460—containing animal fat for lubricity to protect the teeth during boundary lubrication. These types of lubricants oxidized quickly at high temperatures and didn't provide a high level of wear protection.

The two most popular synthetics used in worm applications today are ISO VG 460 PAO and PAG. Each will perform very well. Neither of these synthetics contain EP and they both provide a high film strength and score very high on the FZG test that measures scuffing of gear teeth at different load stages. Mobil SHC 634, which is an ISO 460 PAO with no EP, exceeds 13 stages, the highest level on the test. This results in very low wear rates and energy savings.

Efficiency savings in excess of 7% have been documented. Because of their lower traction coefficient (which is the internal friction in the lubricant) PAGs often provide higher efficiency savings—but PAOs do very well. Temperature drops with a synthetic can be 20-30 F degrees. While PAGs are more common in gearboxes in Europe, more are being used in the United States. A PAG, because of its greater energy efficiency, is a good choice for new gears and can be used on other gears only with the proper flushing procedures. Moreover, PAGs attack some paints. A safer choice to convert a worm gear from mineral to synthetic is to use a PAO.

The following is a case history of the conversion from mineral oil to PAO:

A major can manufacturer used double-enveloping worm gears with an average reduction ratio of 60:1. The company was using a compounded ISO 460 mineral oil. On average, the company was experiencing four gear failures per year, each costing an average of $12,500 to repair. Temperatures typically were 200 F—and in some cases got as high as 215 F. The mineral oil was replaced with an ISO 460 PAO and the failures were eliminated. In fact, to date, 18 months later, there still have been no failures in this equipment. In addition, the average temperature dropped across the worm gears by more than 20 F degrees.

Conclusion
Synthetics are real problem solvers. While they can work well and be cost justified, there are many applications where mineral oils will do just as well. Three applications where synthetics can improve equipment operation and provide major cost savings are air compressors, high-pressure and hot reciprocating compressors and worm gears.

Deciding which synthetic to use is very important. Each candidate will have advantages and disadvantages that need to be considered before a final decision is made.

Keep in mind that the same synthetic type from different manufacturers can give different results. Even though the base stocks may be similar, the additive package may impart different properties from one supplier to another. Make comparisons between the data sheets, but let your final decision rest on field performance. Look at case histories and, if possible, run a carefully controlled plant test where meaningful data can be collected. Even though this will not be possible in some cases, definite equipment improvements can still be observed without rigorous testing and data collection. Be sure to document this data. Since synthetics are more expensive than mineral-based oils, you will want to be very accurate in your cost justifications.

Acknowledgements
The author wishes to thank Tim Taylor of Summit and Dr. Martin Greaves of Dow Chemical for their assistance in the preparation of this article.

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLE-Certified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526.

Oil mist is easily controlled & appliedModern plants use oil mist as the lube application of choice. Plant-wide pipe headers distribute the mist to a wide variety of users. Oil mist is easily produced in an oil mist generator console (Fig. 1) and its flow to bearings is not difficult to control. Flow, of course, is a function of orifice ("reclassifier") size and piping ("header") pressure. Unless plugged by an unsuitable (e.g., an elevated pour point) lubricant, reclassifiers have a fixed flow area that is selected based on bearing size criteria.

Depending on make and system provider, header pressures range from 20"-35" (500-890 mm) of H2O. Modern units are provided with controls and instrumentation that will maintain these settings without difficulty. It should be noted, however, that mixing ratios—typically 160,000 to about 200,000 volumes of air per volume of oil—are frequently incorrect on oldstyle mist generators that incorporate gaskets and O-rings in the mixing head, unless these elastomers have been periodically replaced or properly serviced.

Comparing plants with non-optimized mist entry (Fig. 2) to equipment bearing housings with their modern optimized counterparts (Fig. 3), lubricant and air consumption are about 40% less for plants that have implemented the superior mist entry and vent locations of Fig. 3. This has been reported in the cited references and is implied in API-610 8th Edition (2000) and later standards.

Forward-looking plants have used the API method, i.e. Fig. 3, since the mid-1970s. These plants had recognized that mist entering at locations far from the bearings could have difficulty overcoming bearing windage effects. Windage is most often produced by the diagonally-oriented ball cages in angular contact bearings. If such windage were produced by the left row of the thrust bearing in Fig. 2, the mist would take the preferential path straight to the vent exit at the bottom of the bearing housing and insufficient amounts of oil mist would reach the bearing rolling elements.

A larger quantity of oil mist or specially designed "directional" reclassifiers will be needed with certain bearing types unless the API method is used. This latter method will overcome windage, the flow-induced action induced by the skewed cages.

Environmental & health concerns
For decades, environmental and health concerns related to oil mist have been addressed by using oil formulations that are neither toxic nor carcinogenic. Such formulations are available to responsible users. Appropriate lubricants also have been formulated for minimum stray mist emissions. These, too, are readily available to responsible users.

Stray mist emissions can be kept to very low values by installing suitable magnetically-closed dual-face bearing housing seals (Fig. 4, also Ref.1). Unlike old-style labyrinth or other housing seals that allow highly undesirable communication between housing interior and ambient air, face-type devices seal off this contamination route.

Closed oil mist systems also are available—and have been since first being applied in the Swiss textile industry in the late 1950s. Today, closed systems are in use at several U.S. petrochemical plants. They allow an estimated 99% of the lube oil to be recovered and reused. Closed systems emit no oil mist into the environment and are available to environmentally conscious users.

Header temperature & size
Temperature never has been an issue for properly designed systems. Once a mist or aerosol of suitably low particle size has been produced—and particle size is influenced by the temperature constancy of both air and oil in the static mixing head—the oil mist will migrate to all points of application in non-insulated headers at low velocity.

Ambient temperature has little influence on mist quality and effectiveness. Mist temperatures in headers have ranged from well below freezing in North America to over 122 F (50 C) in the Middle East. Regardless of geographic location, conscientiously engineered systems will incorporate both oil and air heaters, since these are needed to maintain constant and optimized air/oil mixing ratios. The heaters must have low-watt density (low power input per square inch of surface area) in order to prevent overheating of the oil. Users that try to save money by omitting heaters or using undersized headers will not be able to realize the greatest life cycle cost benefits from their assets.

Using undersized headers may increase the flow velocity to the point where the small oil globules suspended in the carrier air experience too many collisions. They may thus agglomerate into droplets large enough to fall out of suspension, causing excessively lean mist to arrive at the point to be lubricated.

Wet sump ("purge mist") vs. dry sump ("pure mist")
In the wet sump method, a liquid oil level is maintained and the mist fills the housing space above the liquid oil. Wet sump (also called "purge" mist) is essentially "old technology"— and primarily used with sleeve bearing-equipped pumps and blowers(Figs. 5 and 6).

Dry sump oil mist describes the application method whereby no liquid oil level is maintained in the bearing housing. (This principle was illustrated earlier in Figs. 2 and 3.) Pumps lubricated in dry-sump fashion are depicted in Figs. 7 and 8. Here, lubrication is provided entirely by oil mist migrating through the bearing.

The application of dry sump oil mist is advantageous for a number of reasons. Among these, we find lower bearing temperatures, the presence of nothing but uncontaminated oil mist and the exclusion of external contaminants. However, one important, but often overlooked, reason involves oil rings (Fig. 9)—or rather the fact that no oil rings are used with this application method.

Oil rings often represent outdated 18th century technology as they were developed for slow-speed machinery during the Industrial Revolution. Elimination of oil rings is one of the many keys to improved reliability of virtually any type or style of bearing. Oil rings are known to have journal surface velocity limitations, sometimes as low as 2000 fpm, or 10 m/s. So as not to "run downhill," which might cause the rings to make frictional contact and slow down, ring-lubricated shaft systems would have to be installed with near-perfect horizontal orientation.

Furthermore, frictional contact often results in abrasive wear and the wear products certainly contaminate the oil. Oil rings will malfunction unless they are machined concentric within close tolerances. They suffer from limitations in allowable depth of immersion and, to operate as intended, need narrowly defined and controlled oil viscosity.

Experience with modern oil mist systems
Actual statistics from a world-scale facility convey an accurate picture of the value of properly applied oil mist technology. This petrochemical plant went on-stream in 1978 with 17 oil mist systems providing dry sump oil mist to virtually every one of the many hundreds of pumps and electric motors in the facility. As stated previously, with the dry sump ("pure") method per current API recommendation, the oil mist is introduced at a location that guarantees its flow through the bearings and to an appropriate vent location. There are neither oil rings nor any other provisions for the introduction of liquid oil on pumps and motors with rolling element bearings at the plant.

Over a period of 14 years, one qualified contract worker serviced these systems by visiting the plant one day each month. In this 14-year time period, there was only one single malfunction; it involved a defective float switch in one of the 17 systems. The incident caused a string of pumps to operate (and operate without inducing even one bearing failure!) for eight hours. In 1992, the combined availability and reliability of oil mist systems at this U.S. Gulf Coast plant was calculated to be 99.99962%.

Concluding comments 
Being aware of the relative unreliability of conventional lubricant application methods involving oil rings and certain constant level lubricators (Fig. 10), knowledgeable reliability professionals can attest to the utility and overall advantages of properly engineered dry sump oil mist systems. Certainly, the known advantages of properly engineered oil mist systems far outweigh the actual or perceived disadvantages. It is unfortunate that much information to the contrary is either anecdotal or pertains to systems that were not correctly designed, installed, maintained and/or upgraded as new technology became available.

Only dry-sump applications will lubricate, preserve and protect both operating and stand-by rolling element bearings. At all times, only fresh oil will reach the bearings. In many instances, bearing operating temperatures with dry sump oil mist lubrication are 10 or even 20 F degrees (6 or 12 C degrees) lower than with wet sump lubrication.

Industry experience with dry-sump oil mist systems is well documented [Refs. 1, 2 & 3] and its superiority over both conventionally applied liquid oil and wet sump oil mist lube applications has been solidly established.

Regrettably, there are still entire plants that try to get by on wet sump oil mist. Wet sump lubrication makes economic sense on sleeve bearings only. Here, its only function is the exclusion of atmospheric contaminants. It does so by existing at a pressure slightly above that of the surrounding ambient air. Often, the wet sump oil level is expected to be maintained by an externally mounted constant level lubricator. However, due to the slight pressurization, and on bearing housings equipped with traditional open-to-atmosphere constant level lubricators [Ref. 2], the oil level in the bearing housing will now be below the oil level in the lubricator. Keep in mind that fully pressure-balanced constant level lubricators will be more reliable than many other wet sump lubrication alternatives available today.

References:

1. Bloch, H.P., and Shammim, A.; Oil Mist Lubrication, Practical Applications, 1998, The Fairmont Press, Inc., Lilburn, GA, ISBN 0-88173-256-7
2. Bloch, H.P., "Case Study in Reliability Implementation," Hydrocarbon Processing, August, 2002
3. Bloch, Heinz P. and Alan Budris, Pump User's Handbook: Life Extension, 2006, The Fairmont Press, Inc., Lilburn, GA, ISBN 0-88173-517-5

Contributing editor Heinz Bloch is the author of 17 comprehensive textbooks and over 340 other publications on machinery reliability and lubrication. He can be contacted directly at: hpbloch@mchsi.com

Maintenance personnel at the plant had noticed that the major brand lubricant we were using on these units looked somewhat different than in the past. When questioned about this, the supplier assured us that no changes had been made. As we continued to pursue the problem, the manufacturer later admitted that the formulation had indeed been changed and the diminished performance we were experiencing was unintended and unexpected. Consequently, we began to look for an alternative lubricant.

The first alternative we selected, an independent brand cylinder lubricant, appeared to work well for about a year. Then we encountered another unintended consequence. The oil carried downstream of the compressor was plugging the chillers in the synthesis loop. At that point, we determined that an oil with a lower flock point (temperature at which wax crystals form) was what we really needed.

We opted to go with Royal Purple's NGL-NS synthetic lubricant as it had no flock point and no sulfur that could poison the process catalyst. After just three weeks, however, we experienced a packing failure on a synthesis loop compressor cylinder. A repetitive failure occurred just four weeks later. In all, we had six packing failures over a twoto- three-month period. Then, the failures stopped—just as suddenly as they had begun.

Interestingly, only the packings on the recirculation cylinders of compressors C & B were failing. We sent samples of the failed packings, along with foreign material found in them, to Royal Purple for analysis. Because the oil travels downstream of the compressor, the supplier attributed the failures to the NGL-NS cleaning out 37 years of "stuff" that had accumulated in the loop. We were advised to persevere with the clean-up and to expect that the failures would eventually stop. They did. Our packing life increased to two years. Subsequently, we also changed packing materials, increasing our current life to four years with expectations of six years life.

Each of these engines/compressors has two turbochargers. In summer months, these units would experience pre-ignition problems due to low intake air volume. We would have to reduce the load on the engines in order to operate. At some point in the past, as part of a lubricant consolidation program, our plant had elected to lubricate this equipment with the SAE 40 weight gas engine oils used in the compressors. We were looking for a better bearing lubricant for the turbochargers and elected to try Royal Purple's Parafilm 68. Again, we found ourselves experiencing unintended consequences.

The first unintended consequence was related to the engines being started with compressed air. The air to the engine is automatically shut-off when the turbocharger speed indicates that the engine is running. After changing lubricants, the engines would not start. We determined that the new bearing lubricants had reduced friction in the turbochargers' bearings so significantly that they were spinning up just on the compressed air, and that they no longer needed engine exhaust gas to do so. We had to reset the air cut-off parameters in order to start the engines.

The second unintended consequence was that the preignition problems in the compressors completely went away. The engines could now be run fully loaded yearround while still maintaining a slight open position of the waste gate valves.

Identifying more opportunities
We operate a 2500 hp Elliott turbo expander in our Nitric Acid Plant that is one of only four ever made and the last still in operation. It operates at 16,000 rpm. This unit has always experienced problems with short bearing life and high vibrations. We thought this resulted from the equipment's fabricated case coupled with too much overhung mass on the rotor. At times, the unit would shake the floor grating so violently that it hurt your feet to stand on it. Replacement bearings cost $8000 and would have to be replaced twice a year. The bearing alarms were normallyset based on whatever vibration levels existed after a rebuild. In an effort to reduce vibrations and extend bearing life, we elected to change out the ISO 32 turbine oil to Royal Purple Synfilm 32. We expected to see improvement from this oil change due to the much higher film strength of the Royal Purple lubricant and we were not surprised. Immediately after the oil change bearing vibrations went down from 4 mils to 2.7 mils. Bearing life went from six months to 20 months. Recently we had the rotor balanced, which further reduced the vibrations to 1.2 mils—and is expected to extend bearing life even longer.

Based on these successes, we began to look for even more opportunities to improve machine performance with lubricant upgrades.

Single screw compressor… 
We elected to change the oil on a 400 hp Vilter single screw compressor at our two 20,000-ton ammonia storage tanks. This compressor had a number of operational issues. It continually tripped on high temperatures. Valves failed to operate because of oil deposits gumming up the valves. We had excessive make-up oil due to the oil's inability to readily separate from ammonia. In this application, we elected to change out the factory oil for Royal Purple Uni-Temp 300 refrigeration oil. Based on assurances from Royal Purple that we would also achieve substantial energy savings, we installed data loggers on the compressor to record volts and amps. All of the operational issues with the compressor disappeared and we documented a 9% reduction in power consumption.

Mycom ammonia compressor… 
Shortly thereafter we changed to Royal Purple oil in the Mycom ammonia compressor serving one of our Nitric Acid Plants. All went well for about a year until we got a water leak in the shell and tube heat exchanger, and unintended consequences recurred. The internals in the compressor rusted and took out the bearings. We also found a black residue in the compressor we believe came from the oil. After a second compressor failure using the new oil, we elected to return to the previous oil as it appeared to have a superior ability to handle wet ammonia.

Rotary screw compressors…
Next we elected to change the oil in our three Sullair rotary screw air compressors to Royal Purple Synfilm. For whatever reason, the larger 400 hp compressor was being lubricated by a major brand multi-purpose mineral oil requiring eight oil changes per year. The two 100 hp compressors were lubricated with a factory synthetic oil with annual oil drains. Being a polyalkaline glycol type oil, the factory oil was incompatible with most other lubricants. Thus, it was necessary for Royal Purple to supply its Royal Flush product to flush the old oil from the compressor before adding new oil. In addition to its price advantages, the new oil has reduced discharge temperatures by 12 F degrees and has extended oil drain intervals via oil analysis to 12,000 hours.

4-stage urea plant compressors… 
In April of 2002, we elected to address issues we were having with our two Clark CMB 4-stage compressors in the urea plant. These units, which compress CO2 to 3000 psi, were experiencing excessive cylinder ring wear, packing sealing problems and plugging of the downstream separators. We elected to change the major brand cylinder lubricant to Royal Purple CAP701W ISO 220. This proved to the solution to each of these issues. So again, we looked for other areas where we could improve the performance and reliability of our equipment with lubricant upgrades.

Steam-driven centrifugal compressor… 
We also looked at a steam-driven 5000 hp Allis Chalmers centrifugal compressor in Ammonia Chiller Service. The speed increaser gear box (4900 rpm input/12,800 rpm output) was in high vibration alarm. The turbine and gearbox share a common lube sump containing 1200 gallons of ISO 32 turbine oil, so we could not drain and replace the oil because shutting the turbine down meant shutting the plant down. We decided to drain the turbine oil to the lowest level we thought was safe and then we added six drums of Synfilm 32 to the existing oil (27 ½%) hoping to get enough film strength into the oil to bring the vibrations down. It worked. Vibrations were reduced from 0.2 IPS to 0.17 IPS (a 15% reduction), which was below the alarm limits. We ran the turbine until our next scheduled turnaround. We drained and replaced the major brand turbine oil with Parafilm 32 and have run the turbine and gear box without incident for the past five years.

This compressor has a separate oil system for the trapped bushing seal that seals the ammonia into the compressor. Feeling good about our successes, we decided to tackle what we believed was a lubricant related seal problem. The major brand ISO 32 R&O oil we had successfully used for years suddenly became unavailable. We were assured that the supplier's new offering was equally good, but then some of those unintended consequences reared their ugly heads again. What used to be minor carbon deposits found in the seal at turnaround became significant carbon deposits on the seal—which caused premature seal failure and plant shutdown. We consulted with Royal Purple about a replacement oil and began a new round of unintended consequences.

First we tried Synfilm which didn't separate well enough from ammonia. To overcome this we changed to Uni-Temp, which we knew separated rapidly from ammonia, but its high solvency began to aggressively clean up deposits from the seal system that were carried to the seals—again causing premature seal failure. Finally, we changed to Royal Purple Barrier Fluid FDA 56, which solved the problem once and for all. That's because this product does not have the cleaning abilities of the Unitemp. In this case, we felt it simply was better to leave whatever "stuff" was in the system alone.

150 pumps… 
We operate over 150 pumps at the East Dubuque Ammonia plant, all of which had been lubricated by an ATF fluid. A little over a year after changing these pumps over to Synfilm, it occurred to us that we had not experienced a single bearing failure since the move. Even now, we seldom see bearing failures on these pumps—the few problems we do have are usually seal failures.

The road to success
Today our plant is running better than at any time in its 40+ year history. Budget trends are down and equipment availability is up. We are currently at two-year turnaround intervals and feel we could easily go to three. Though it may have started as an accidental journey, we have learned that good lubrication is key to reliability and good lubrication begins with optimum lubricant selection. We also learned that solutions are not always obvious and that patience and perseverance are required in order to stay the course to some solutions.

Sometimes we wound up having to take two steps back before being able to take three forward. We also learned that there is no such thing as a magic bullet—or magic oil. For many applications we see no advantage in using anything but traditional lubricants. For many others, the benefits vastly exceed the cost of premium performing lubricants.

One thing is certain, however. We no longer look at lubricants as an expense. Instead we look at lubricant selection as an opportunity to maximize productivity and profits.

Lance Wilkinson is maintenance superintendent/technical manager with Rentech Energy Midwest, in East Dubuque, IL. He has extensive experience in the Petro-Chemical Industry, including 21 years in engineering, seven years as a craftsman and supervisor and three years as a machinist. Wilkinson holds a BSME from the University of Texas at Austin. E-mail:lwilkinson49@sbcglobal.net

Lubrication Management & Technology’s “Mineral-Based Lubricant Exchange” guide has been compiled to help you in the event that substitutes must be chosen. The chart on the following pages has been designed as an easy-to-use cross-reference of the products of major lubricant formulators, based on the information they provided to our editors.

Keep in mind that the products shown on our chart are general guidelines for comparison purposes only— they do not infer that performance is interchangeable. If you are considering a lubricant substitution for a specifi c application, you MUST consult the respective formulator(s) to ensure proper performance.

Notes on using the chart
Viscosity is a widely accepted property for comparing lubricants. It is expressed in several ways: ISO, Saybolt, AGMA and Kinematic. Note that the viscosity equivalents of ISO and Saybolt are what we have used in our chart to compare the various products of the listed formulators. (Refer to Figs. 1 and 2 for a comparison of common viscosities and to see the effect of temperature on viscosity.)

Analyzing the bigger picture
Although following recommended oil-change and greasing schedules is the usual way of doing business in a facility, this alone will not optimize machine performance and minimize downtime. Regular oil analysis—conducted in-house or by a qualified lab—is another powerful tool to use in enhancing reliability and increasing uptime. Remember that accurate and timely oil analysis can alert personnel to impending lubricant deterioration or machine malfunctioning, and allow them to initiate corrective action—well before an actual failure occurs.

Joe Foszcz is a contributing editor to Lubrication Management & Technology. For more information, e-mail him directly: jfoz@atpnetwork.com

"It is critical to match the proper lubricant with its intended application," says Bill Stein, a product application specialist with Shell Lubricants. "When developing compressor lubricants, consideration must be given to the fluid type and additives used, as well as the intended use of the product."

To meet the complex needs of today's air compressors, Shell is now offering next-generation technology in its line of air-compressor oils: Shell Corena AP, Shell Corena AS and Shell Corena S.

Shell Corena AP Oils
These products are intended for the lubrication of industrial reciprocating air compressors, in particular, those up to and above air discharge temperatures of 220 C (428 F) with continuous high delivery pressures. According to the manufacturer, Shell Corena AP incorporates a combination of specially selected synthetic esters and advanced additive technology. As a result, this product works well in the most demanding of conditions, handling continuous high pressures and high temperatures, where traditional mineral oils are not suitable. A low tendency for deposit build-up helps promote continued high compressor performance over long periods. Moreover, the normal valve maintenance period, typically between 250 and 1000 hours of operation using conventional mineral oils, can be extended to 2000, or even 4000 hours.

Shell Corena AS Oils
These advanced synthetic rotary air compressor oils use a specialized additive technology. Shell Corena AS is capable of giving high performance in oil-flooded air compressors of screw or vane design. It provides effective lubrication, even under severe conditions, to oil-flooded single- and two-stage compressors, in particular those operating with output pressures of greater than 20 bar (290 psi) and with air-discharge temperatures greater than 100 C (212 F)— including intermittent operation under these conditions.

The manufacturer also notes that Shell Corena AS can help increase oil drain intervals significantly compared to conventional mineral oils, where allowed by the manufacturer— up to a maximum of 12,000 hours, even when operating at a continuous maximum discharge air temperature in excess of 100 C (212 F).

Shell Corena S Oils
A premium performance mineral oil, Shell Corena S is suitable for the lubrication of rotary sliding vane and screw air compressors, operating with lower discharge temperatures. Based on a blend of high-viscosity index, Group II paraffinic mineral oils and carefully selected additives, the oil provides thermal stability, good water-shedding properties, good seal compatibility, anti-oxidancy, anti-wear and low oil carryover. In field use, Shell Corena S has demonstrated more than 5000 hours of operation.

Shell Lubricants
Houston, TX