To solve its cavitation problem, Hutchinson chose a 20” Singer Pressure Reducing Valve (PRV). |
Smaller mixing butterfly valves for the winter water demand were considered, but that would have involved piping modifications. The simplest, most reliable, cost-effective solution was a Pressure Reducing Valve (PRV) with Anti-Cavitation trim in front of the plant. In this case, the PRV would take the main pressure drop while the mixing butterfly valves would be used for trimming the flow.
After looking at all the flow options, Hutchinson decided to go with a 20” Singer Pressure Reducing Valve (S106-PR-AC) because it has a Single Rolling Diaphragm (SRD) that provides smooth, steady and precise pressure control from maximum to virtually zero flow. The effective area of a single rolling diaphragm remains constant so the bonnet is much smaller and lighter than a flat diaphragm. A measured quantity into the bonnet control chamber always gives the same smooth movement of the inner valve through the entire stroke. A smaller bonnet also makes the valve lighter and safer for maintenance, while the smaller control chamber enables it to respond faster to changing pressures. By eliminating the seat chatter at low flows (capable down to as low as 50 gpm), the SRD avoids injecting small pressure pulses into the piping, which, over time, may increase leakage, losses or pipe bursts.
Don Koci, superintendent of Hutchinson’s Water System, said, “Once the new PRV was put in place, the unbearable sound from cavitation was no longer present, and we now have consistent, reliable flow and pressure.” Going forward, the city should no longer have to incur the costs of replacing the valving on an annual or biannual basis.
Singer Valve is exhibiting at AWWA’s ACE16 expo in Booth 641.