Accessing & monitoring a station?s performance

Dec. 12, 2002
Officials with Flowtronex PSI® recently completed a municipal pump system for the United States Little Rock Air Force Base in Jacksonville, Arkansas. Working with Stephen Jeffus of Instrument and Supply and Sam Gates of Garver Engineering, Flowtronex created a pump station using advanced technology to access and monitor the station?s performance. ?In order to be successful, we had to maintain appropriate water levels in the tank and adjust for various pressures at the station intake,? stated Steve Frasure, director of Water Works for Flowtronex PSI. ?That meant it was imperative that we design a well-balanced system that constantly senses changing conditions at both ends and adjusts accordingly.? The Little Rock project utilizes a horizontal split case station with a Variable Frequency Drive using dual input signals that enable the station to function properly. Relying on the input signal of a system pressure transducer, the VFD slows or accelerates to maintain a stable pressure. At the same time, the station?s PLC receives a signal from the tank indicating whether the current level has decreased or increased. Based on the variant conditions at any given time, the pump station will react to ensure the fill tank is well supplied and the station does not run off the curve if a high incoming pressure situation occurs. ?This project was particularly challenging because the Little Rock Air Force Base imports water from three municipal sources,? said Mark LaVarnway, Flowtronex application engineer. ?The station had to deliver the water to a supply tank downstream from the pump station. It was particularly difficult to create a pumping system that would adequately control incoming water from these various sources as well as track the level of the fill tank.? To regulate the flow, all communications are handled by a PLC based on a common protocol that easily interfaces with the Air Force base?s SCADA system. This allows Air Force personnel to monitor output and voltage as well as temperature using information retrieved directly from the pump station. In addition, a circular chart recorder with totalizer was installed to provide a running history of the station?s performance, which can be produced in either digital or analog format. This will allow end users to secure a hard copy of the pump station?s performance for evaluation at any given time. The pre-assembled and tested pump system was delivered on an open I-beam skid. Once situated at the Air Force base, workers poured concrete through the beams to create a concrete floor and built a housing unit around the station. ?I believe this venture not only demonstrates Flowtronex?s capability to provide solutions to challenging projects, but it also shows effective partnering with contractors and the United States government,? LaVarnway added.