Centrifugal pumps are designed to operate within a very confined efficiency envelope. A pump operating close to its Best Efficiency Point (BEP) consumes less power, requires less maintenance and fails less frequently than one operating away from its BEP (see Fig. 1). Unfortunately, most pumping systems were designed when electricity was abundant and cheap. Production throughput and stability was king. Once in place, pumps are seldom the focus of the operation, as long as they are running—and the wasted power is not easily seen.
What to do?
While one-off system assessments can identify "low-hanging fruit," when it comes to the greatest savings potential, they're mere snapshots of an operation: Without ongoing monitoring, such assessments can't accurately quantify wastage over time. Thus, it's difficult to develop a business case for improvements and, once changes are implemented, to quantify results.
Fig. 1. A pump operating close to its BEP (Copyright Barringer & Associates, www.barringer1.com). Click to enlarge.
Developed to optimize massive dewatering pumps operating thousands of feet underground in South Africa's gold mines, TAS PumpMonitor continuously compares current operation against the optimum duty defined by the Pump Performance Curve, the most reliable source outlining a pump's potential performance. Data can be input manually or gathered in real time from standard instrumentation via a PLC-based communications system. Complex algorithms then analyze the data to help identify the optimal performance-enhancing corrective action.
TAS PumpMonitor looks at the entire system and classifies inefficiencies into three types: wear, duty and volumetric. This distinction quantifies the wastage per cause and also helps users identify the corrective actions that will result in immediate efficiency improvements and ongoing savings throughout the pump's life cycle. A system with a high volumetric loss is shown in Fig. 2.
Having established an accurate baseline, the PumpMonitor provides ongoing measurement of the effectiveness (or ineffectiveness), of system improvements. In addition to quantifying wasted electricity, the product supplies information—fed to an engineer's desktop in real time via the Internet—to identify equipment failures before they manifest. This facilitates relevant proactive maintenance and saves costly man hours and production losses.
TAS PumpMonitor has proven its effectiveness not only in mine dewatering but also in process- and bulk-water applications. Its accuracy has been audited by a major power utility in a technology-proving project that quantified savings of over 30% of the power consumed in a typical municipal-water pump station. The first U.S. application, in Chicago, IL, has demonstrated the product's compatibility with local communications systems. MT
According to Gunnar Hovstadius, an internationally recognized authority on pumping-system efficiency, TAS PumpMonitor is a logical and powerful extension of current system-assessment efforts. The key?
"This product provides pump users and consultants a convenient means for accurately quantifying savings potential AND tracking the success of improvements."
TAS Online (Pty) Ltd.
Johannesburg, South Africa and Ringwood, IL
(TAS Online is seeking additional U.S. sales representation.)