Escalating energy costs are helping create conditions for a critical reassessment of fluid-handling systems, including their heart: the good, old, dumb, mechanical pump.
Whether powered by air or motor, pumps are the muscles that propel anything that can fit in a pipe. They are essential to cool, heat, cook and transport both products and utilities, whether liquid or gas. Pumping systems are estimated to consume almost 20% of the global energy from electric motors, and poor fits between the pump and the power source tend to be ignored as long as production schedules are met. As a consequence, oversized motors and inappropriate pumps populate plants, including those producing foods and beverages.
“Nobody wants to design a pumping system that could throttle performance and disrupt the process,” allows Gregg Romanyshyn, technical director at the Hydraulic Institute, a Parsippany, NJ, trade group. But if 90 lbs. of pressure are needed, the tendency is to engineer 95 lbs., and an extra 40% of flow might be factored in to accommodate future capacity that never materializes. A “don’t fix what ain’t broke” mentality takes charge, and oversized power or under-utilized pumps perpetuate inefficiency.
Pump specialists still can be found in chemical plants, but those experts exited the food and beverage building years ago, states Bill Beard, market development manager in Grundfos Pumps Corp.’s Appleton, WI, office. “How pumps interact with each other and within the system is critical,” he says, yet in-house insight often is lacking. “Dairies know they have pump issues with their waste stream, boiler feed and other fluids, but they need support to understand why a pump failed.”
Pressure valves on PD pumps are notorious energy wasters. Fortunately, they are being replaced by variable speed drives, particularly in food and beverage, where pumping flexibility and the prevalence of CIP systems make variable speed important. “Every minute that a control valve is in place, it’s robbing a system of efficiency,” Beard points out. Besides variable speed drives, Grundfos is pushing into the realm of intelligent pumping with CUE, a ladder logic-based control panel that simplifies the process of setting rates and alarms and doing other programming. “You’re giving operators and plant engineers a control panel that speaks the language they speak,” he says.
Simplifying fluid flow for the user can be complicated, as seepex Inc.’s Michael Dillon can attest. His Enon, OH, firm was an early participant in the supply of intelligent pumps, the marriage of mechanical pumping with electronics (see related story on page 58). Intelligent pumping has advanced fitfully, but Dillon believes seepex has a winner with its fourth generation of progressive cavity pumps with a variable frequency drive (VFD) and on-board electronics. The package was developed in partnership with Emerson Process Management and delivers run-dry and dead-head protection with direct flow control, eliminating the need for recirculation with control valves.
Signal type and tuning, compatibility issues and other factors worked against earlier versions of seepex’s intelligent pumps. One hang-up was the use of DC motors, an issue in hygienic environments where carbon dust from DC brushes is a cause for concern. The new package uses AC motors, and no programming or defining of functionality is required. “You’re up and running in a day,” says Dillon.
Superior speed control and stability result in less energy consumption than a pump powered by a VFD-equipped motor, he adds. His system can throttle down to flow rates as low as 10 oz. an hour. The big challenge to greater adoption of intelligent pumps is competition from air-operated units. “They will use 4 to 5 times the power of an electrically operated pump,” Dillon maintains, though portability and low initial price make them appealing.
Air-powered improvementsFabricators of compressed-air pumps are sensitive to the energy-hog label, though the energy conversions that must occur make waste unavoidable. Wilden, one of the largest makers of air-operated double-diaphragm pumps, recently introduced an air distribution system that can slash volumetric flow rate in half. Housed in a section external to the liquid chamber, the device gives manufacturers the ability to regulate air flow to match need, similar to trimming the impeller but with the flexibility to readjust the valve for other production runs.
Called the Pro-Flo X, the control device gives operators an adjustable dial that can be reset as flow rates and pressure requirements shift. In tests performed with water at a 1-ft. lift, a 2-in. pump consumed 28.1 standard cubic feet of air per minute (SCFM) to move 53 gpm, compared to 33.4 SCFM for a conventional double-diaphragm pump. As flow increases, savings escalate: at 131 gpm, the system requires 63.3 SCFM, compared to 139.5 SCFM for a conventional pump.
“It’s nothing more than a needle valve at the inlet of the pump,” explains Wallace Wittkoff, global hygienic director for Dover Corp.’s Pumping Solutions Group. Formed last year, the group brings together brands such as Wilden, Almatec and Mouvex.
Atlanta’s Unibloc Pump Co., which goes to market as Technoflow, has focused on shrinking the footprint of its PD pump and gearbox combination, according to engineer Bhavesh Patel, though it also has altered the rotor profile and achieved tighter tolerances between the rotor and the housing and front cover by upgrading CNC machinery. The cumulative effect is a 20% improvement in efficiency, Patel says.
Additional efficiency gains will come in increments, given the nature of sanitary fluid movement. “You can never press the rotor into the housing of a sanitary pump; for one thing, you would need a much larger motor to drive it,” Patel points out. Additionally, metal-to-metal contact is unacceptable, making some product slip unavoidable, particularly as viscosity thins.
Applications drive pump selection, and if a fluid’s viscosity and characteristics dictate centrifugal pumps, that is what is used, despite their relative inefficiency. The good news, according to SPX Corp.’s Jim LeClair, is that great strides have been made in the hydraulic efficiency of centrifugals.
Twenty years ago, 45% of energy input into a centrifugal might be converted to flow and pressure; today, efficiencies of 85% are typical, allowing manufacturers to step down in motor size, says LeClair, a product manager with SPX’s Delavan, WI-based APV line.
APV advanced the science of self-priming centrifugal pumps in 2002 when it introduced the Ws+ series. Besides reducing energy consumption as much as 49%, noise levels were lowered significantly. Instead of radial vanes in the impeller ring that screeched anytime a particle exceeding 0.008 in. passed through, the adjustable impeller accommodates particles as large as 0.25 in., reducing wear and tear while lowering the decibel level.
“In dairies and other fluid handling applications, many manufacturers were able to go down one complete pump size with those self-primers,” says LeClair, “in part because the changeable impeller greatly expanded the feet of pressure head available compared to the previous version.”
Rotor clearances and other factors in pump efficiency haven’t changed much at Middleton, WI-based Fristam Pumps, which relies on a steady roster of component suppliers to keep tolerances tight, applications supervisor Sam Raimond says. But the prevalence of VFDs in pumping systems has enabled food producers to improve their efficiency profiles significantly, he adds.
“Ten years ago, VFDs were cost prohibitive,” Raimond reflects. “I supplied two-speed motors” with some orders, but that was a stopgap solution. Today, as many as four out of five pump and motor packages placed into food production service are equipped with VFDs.
Like most pump makers, Fristam has limited opportunity to help optimize fluid handling systems. “I always size the most efficient pump for the duty point,” Raimond says, leaving it to a skid manufacturer or engineering firm to address overall efficiency. But as electronic complexity increases, new skill sets are being demanded from the engineers who design pumping systems.
“We’re always getting drawn into helping people with system design,” seepex’s Dillon says, and the movement toward intelligent pumps will require more interdisciplinary skills. While that poses a challenge, greater collaboration between the component suppliers of pumping systems holds the promise of additional efficiency gains.
For more information:
Paula Hollywood, ARC Advisory Group, 781-471-1124
Wallace Wittkoff, Dover Corp.’s Pump Solutions Group, 502-905-9169, firstname.lastname@example.org
Sam Raimond, Fristam Pumps, 608-831-5001
Bill Beard, Grundfos Pumps Corp., 920-574-6219, email@example.com
Gregg Romanyshyn, Hydraulic Institute, 973-267-9700, ext. 114
Bhavesh Patel, Unibloc Pump Inc., 770-218-8900, firstname.lastname@example.org
Michael Dillon, seepex Inc., 937-864-7150, email@example.com
Jim LeClair, SPX Corp., 262-728-1900
Pump optimization action planSoftware assessment tools, e-learning courses, legions of consultants: there’s no shortage of resources for organizations that want to determine if their pumping systems are operating as efficiently as possible. For those who prefer the traditional classroom encounter, the Hydraulic Institute’s Pump Decisions Matter program is testing a series of one-day courses on the topic, “Pump System Optimization: Opportunities to Improve Life Cycle Performance.”
How to identify the most likely areas for improvement, analysis tools for pumping systems and lifecycle cost analysis are some of the course objectives. Development of an action plan for participants’ own facilities will conclude the day’s activities. The first course was conducted in Minneapolis in August, with a full schedule of courses nationwide planned later this year. For information, visit the group’s Web site: www.pumpsystemsmatter.org.
Intelligent pumps save energyPumps that integrate control devices, variable frequency drives and even software that integrates asset management capabilities are a small but growing segment of the market, concludes a new study by Paula Hollywood, an analyst with Dedham, MA-based ARC Advisory Group. However, she cautions, manufacturers and suppliers need to rethink their approach to these “mechanical workhorses” if they are to realize the benefits, including energy savings.
“There are so many disciplines involved in an intelligent pump that no one wants to take ownership” at either the manufacturer or supplier level, says Hollywood. “The cultural issues are the major inhibitor to (market-share) growth.” Instead of considering pumps as dumb parts in a fluid handling system, food and beverage companies need to view them as components in a dynamic process control network, she advises.
Similarly, pump suppliers should partner with experts in process control to develop systems.
Building automation specialists are the biggest users of intelligent pumps, relying on them in HVAC systems that must adjust to fluctuations in occupancy rates and other factors affecting chilled-water demand. Oil and gas companies, refineries and other installations also are making greater use of the technology. But many process companies continue to focus on initial purchase cost, says Hollywood, and intelligent pumping comes at a premium. Over a 20-year service life, however, the intelligent pump delivers significant economies. “You can save perhaps 35% in energy costs” alone, she points out. Lower maintenance and other costs add to the ROI.
Hollywood’s report is available for purchase through firstname.lastname@example.org.