Municipal Applications - Monthly Job, July 2005

Godwin PrimeGuard Controller Eliminates Complications

A recent sewer bypass in Virginia, utilized Godwin high head Dri-Prime pumps with Godwin PrimeGuard controllers to meet a complicated challenge. Project coordinators were faced with controlling the operation of pumps on a 24-inch force main with possible flows up to 13 MGD, 12-foot suction lifts, and 294 feet of total dynamic head while avoiding potential problems during pumping.

To meet the challenge, a Godwin Pumps' sales engineer from the Richmond rental location, worked with the county, the contractor and the engineer to develop a bypass pumping system consisting of five Godwin high head Dri-Prime pumps.

Two Godwin 10 x 8 HL225M Dri-Prime pumps, utilized as primary pumps to handle 6 mgd of average flow, were configured with Godwin PrimeGuard controllers. A level transducer on each pump senses water pressure in the wet well and signals the PrimeGuard controller, programmed on site, to vary the speeds of the primary pumps as required. This programmable control feature ensures a constant variable flow with minimal starts and stops, eliminating initial overload or shock to the system and avoiding any potential problems including water hammer.

Two more high head Dri-Prime pumps were used as secondary pumps to handle an additional 7 mgd of potential wet weather flow. A final pump was established as a backup to the secondary pumps. All five pumps were tied into four 500-gallon fuel cells.

The sewer bypass pumping system enabled the county to perform pump station upgrades without sacrificing services. The project included the installation of two 4 million gallon retention tanks and a new junction box for the influent gravity sewer. The bypass diverted flows from the 42" gravity sewer line located between the creeks.

The contractor provided labor and equipment operators who worked directly with a Godwin fusion technician to have the pumping system operational in one week. The job has been running for two months and is currently still on rent.

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