Studies on Techniques and Devices of Controlling Surge in Pipelines

Water hammer in pipelines may cause serious accident. To solve the problem, three mechanical devices — rubber tube relief valve, metal plug relief valve and pressure-surge-proof valve actuator are developed. The first two devices are for controlling the surge after water hammer occurs, the last one is for preventing it from occurring at valve. When the monitored pressure increases at a rate higher than the setting rate, or the pressure reaches the setting maximum value, the relieve valve will release liquid to constrain strong surge from water hammer. The key part of one relieve valve is a rubber tube; the other is metal valve plug. Both of the relief valves could also be used as common relief valves. The pressure-surge-proof valve actuator works on the principle of damping the movement of the valve stem at the closing end of its travel. The key part is a two-stage-damping device, which is installed onto a valve actuator. When the valve stem goes into the last part of full travel the device provide damping action in two stages to weaken the surge from valve opening or closing.