Water hammer problem
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This post was last edited by weiqun on 2010-11-27 at 22:53. I’m wondering whether air entrained in the water can cause water hammer due to rapid changes in flow velocity and pressure in the pipes; and if there is no air entrained, then water hammer won’t occur, right? There is also a long section of pipe in the oil pump outlet delivery pipeline that runs from the fifth floor to the first floor; the fluid in this pipe returns to the pump inlet. At the highest point of this pipe on the fifth floor, a 50-mm pipe is connected to the highest point of the pipe ahead of the pump inlet on the first floor. (To provide buffering, the pipe ahead of the pump inlet on the first floor is designed as a curved pipe that goes from low to high and then back to low; this highest point is the top of that curve.) What is the purpose of this small pipe? Why? I hope everyone can answer my questions completely. Thank you.
The solution to water hammer is to install a check valve at the pump outlet.
Reply to 2# lxn_663: Check valves are available, and they should be of the slow-closing type. In my opinion, ordinary check valves cannot address the issue of water hammer; they can only prevent backflow of the fluid from causing problems with the pump. But they’re useless for pipes, as the pipes are quite long and at different levels. What’s important here is preventing issues in the pipes, after all.
It is suggested that the original poster draw a diagram to explain the question.
Installing a check valve is a passive measure; to prevent water hammer, it is necessary to control the operation of the pump, and one must avoid opening and closing the valves abruptly.
First question: It is recommended that the original poster define water hammer online or in forums. The presence of air bubbles in water usually leads to cavitation, while water hammer occurs when a valve is suddenly closed or a pump stops abruptly, causing the fluid to flow back or, due to inertial forces, generating a strong shock wave that results in pressures many times higher than those under normal operating conditions； For the second question, it’s better to attach a simple diagram.
Reply to 6# luoheng116: Let me ask again then – does rapid opening or closing when water is entrained in the steam increase the risk of water hammer? Won’t it work if no water is carried along?
Water in the steam will definitely cause water hammer; therefore, steam pipes should be equipped with traps at appropriate locations
Water in the steam can cause a steam hammer effect; it’s absolutely impossible for water to cause a steam hammer. When two different streams of steam meet, it often leads to a steam hammer effect