How can pipe water hammer be eliminated?

You currently have the water hammer suppressor installed at the end of the outlet pipe, and that is exactly why the effect is not noticeable. The main cause of the actual water hammer phenomenon is usually the sudden closure of the check valve; after the pump stops, the water flowing back downward strikes the check valve at high speed due to inertia. Therefore, the focus is on protecting the check valve and reducing water hammer caused by its sudden closure. Methods to improve the elimination of water hammer: 1. Move the water hammer eliminator from its position at the end of the pipeline to a location near the check valve behind the pump outlet (i.e., at the location indicated by the arrow): – This is a reasonable and correct approach. This can directly alleviate the pressure waves generated when the check valve closes, reducing the energy of water hammer impacts. 2. Use a slow-closing check valve or a slow-closing check valve at the water pump outlet: – Slow-closing check valves close more slowly, which can significantly reduce the water hammer effect caused by sudden shutdown of the pump. 3. Install a pressure tank (water hammer absorber) at the pump set outlet: A properly sized pressure tank can effectively absorb and release pressure fluctuations caused by the shutdown of the pump, serving as a buffer. 4. If conditions permit, changing the control method to an inverter and gradually adjusting the speed, rather than using a soft starter, can also completely resolve such problems. In summary, the simplest and most effective measure is to move the existing water hammer suppressor closer to the outlet of the check valve. If it still cannot be completely eliminated, considering adding more slow-closing check valves or pneumatic pressure stabilizing devices could help improve the situation. .

You can try replacing the check valve with a pressure control valve

There are also this type of valve; I’ll take a look at it

You’re absolutely right; I also plan to try each option one by one – first moving the water hammer suppressor to a lower position, and if that doesn’t work, then replacing it with a check valve. Adding an inverter is the last option.

This post was last edited by tcdlb on 2025-7-25 07:38. To eliminate pipe water hammer, comprehensive measures need to be taken in terms of design, operation, and equipment. The following are specific methods:  1. Optimize design and operation • Control flow velocity: Reduce the flow velocity of the fluid in the pipes (it is generally recommended to keep it at ≤1.5 m/s) in order to minimize the impact force that occurs when pumps stop suddenly or valves are closed. • Extend the valve opening and closing time: Ensure that the shutdown time of the valve/pump is longer than the round-trip cycle of the pressure wave. • Avoid rapid start-stop operations: Use soft start/stop devices (such as variable-frequency pumps) to prevent sudden interruptions in water flow. 2. Install specialized protective equipment • Water hammer arrestor: ◦ Pneumatic type: Absorbs pressure fluctuations using air bags (suitable for liquid pipelines). ◦ Mechanical: Such as slow-closing check valves, which close in stages to reduce shock. • Pressure regulating tower/stabilization tank: Installed at high points or key locations in the pipeline to provide a buffer area. • Pressure relief valve: It opens automatically to release pressure when it exceeds the set value. • Air valve: ◦ Intake and exhaust valve: Installed at the high point of the pipeline; air is drawn in when negative pressure exists, and air is expelled when positive pressure exists. ◦ Retarder air valve: delays closure to prevent secondary water hammer. 3. System maintenance and inspection • Regular venting: Prevent gas accumulation in the pipes from causing air hammers. • Check the check valve: ensure it operates smoothly and avoids sudden closure. • Pipeline support reinforcement: Reduces pipeline vibration or displacement caused by water hammer. 4. Handling of special scenarios • Long-distance water transmission pipelines: Buffer facilities such as pressure regulation chambers should be installed at intervals. • Water supply for high-rise buildings: Variable-frequency pump sets or air tanks are used to stabilize pressure. • Industrial high-pressure systems: Use hydraulic control valves or two-way buffer tanks. 5. Simulation and verification: Use software such as HAMMER and AFT Impulse to simulate the water hammer effect, verify the effectiveness of protective measures, and optimize the design. In summary, water hammer protection requires a combination of preventive measures (design, operation) and remedial measures (equipment installation), with the appropriate approach selected based on the specific characteristics of the system. For complex systems, it is recommended to consult professional engineers for targeted analysis.

Given your current process and the large pressure difference, it is likely a problem with the choice of check valve; this check valve should be a slow-acting type. Also, the water intake should have a check valve as well. Additionally, did the \"water hammer\" phenomenon that occurs in this process arise at the beginning of testing or later on? If it’s the former, it should be a design issue. If it is the latter, it is necessary to check whether the check valve is damaged; ideally, a check valve should be installed at the water intake. Moreover, the damping effect provided by that water hammer silencer is limited, so there is no need to move it. The key issue is to first identify the cause of the problem, as that is what deserves the most attention; for reference only.

I think it would be better to add a U-shaped bend at the pump outlet as a buffer

This post was last edited by wsts00100 on 2025-9-5 10:28. Here’s a water hammer calculation software for you. . .