By Derek B. Scott and John R. Helf
Although the use of gear actuators in larger valves are beneficial, resilient wedge gate valves, introduced domestically more than 40 years ago, inherently require a much lower operating torque. For this reason, the operational need for the use of bypasses has long been questioned. In fact, today, most municipalities consider the bypass to be an added component to the system that must be maintained and accounted for, and the engineering community rarely requires bypasses.
This position is based on logic and inherent field experience, but until recently, there was no empirical data to support the position that bypasses, for the routine operation of resilient wedge gate valves, are not needed. To determine the effects bypasses might have on large diameter resilient-seated gate valve operation, AMERICAN Flow Control conducted a series of operational tests on an AFC Series 2500 30-inch resilient wedge gate valve.