In liquid operations, wherever a sudden stop in logistics, a large amount of vibrational waves are generated both upstream and downstream, a phenomenon known as water hammer. It is usually caused by sudden closing of the pump or sudden closing of the valve when the closing element suddenly sucks in the valve seat (tank blocking effect) when the valve approaches the closed position. For control valves, the tank lockout effect is caused by a low thrust actuator that does not have enough rigidity to maintain close proximity to the valve seat. In some cases, valves with a quick-open or installed straight-line flow can also cause a water hammer effect. Although the water hammer produces a lot of noise, the real damage is caused by mechanical failure. As a result, the kinetic energy rapidly changes to static line pressure, which is known to break the line or damage the pipe support and damage the line connection. For valves, the water hammer can vibrate through the spool, which can lead to failure of spools, gaskets or packing.For valves, the best defense against water hammer is to prevent any sudden pressure changes in the system. These include slowing down the valve itself or providing a greater degree of rigidity when the closure element is near the valve seat. To prevent pressure fluctuations, the valve should be closed at a uniform rate of change. In some cases, you may be required to change to the equal percentage feature when using the quick opening or setting straight line feature (which is close to the quick opening feature). For control valves that must be throttled close to the valve seat, use unusual stiffness actuators, such as spring-loaded pneumatic actuators or hydraulic actuators, or special notches on the travel sleeve of a manual quarter-turn actuator , Will reduce or prevent the dissolution tank blocking effect. Setting some type of anti-ripple on the pipeline system also reduces water hammer. This can be done with a pressure relief valve or inflation hose, which reduces the length of the line. In addition gas may be injected into the system, the injection of gas can reduce the density of the fluid and provide some compressibility to handle any sudden fluctuations.
