Abnormal noise in Shimizu centrifugal pump
Thread Content
The Shimizu centrifugal pump makes a thudding sound every few minutes; the pressure gauge drops to zero instantly before returning to its normal value. I would appreciate some advice on this issue. Thank you!
Why could an outlet check valve cause this phenomenon?
It only pushes back when pressure is applied. Periodic, on and off
Thank you. But there is always flow at the pipe outlet, so the check valve should remain open at all times.
It’s just a suggestion to check it. If you think it’s all good, then it’s good
If there is an online trend for the flow meter, or a current trend, it can be said that there is always flow. Otherwise, it has no basis. If such abnormal noises occur, it is likely due to issues with the manufacturing process. It is recommended to check the user’s data, or look at the usage trend records (trend lines) of your own unit to see how they are performing, and then share them for discussion. For reference.
Thank you all. I’ll try using a one-way valve first
You don’t need to change it right away; you can think about it further. When the pressure drops to 0, it means there is no pressure inside the pump, but there is pressure in the pump’s output pipeline, causing water to flow back into the pump. This will close the check valve, and a thudding sound will be heard at the moment it closes. Now consider why the pump pressure becomes 0. 1. Evacuate the pump and check whether the liquid level in the inlet tank is too low. 2. Check if the inlet filter is clogged. 3. Check whether there is gas inside the pump and refill it. 4. Check if the impeller and the inlet are blocked, as well as whether any foreign objects at the bottom of the tank might be blocking the pipelines. 5. Check whether there are any leaks in the seals of the connection flanges at the pump inlet, as this could allow gas to enter the pump. With a self-priming pump, it could be something like the check valve getting stuck, etc. (For reference only; please let us know how the issue was resolved once it’s fixed, as there are rewards available.)
The inlet pipeline and the liquid level inside the tank have been checked and no issues were found; the pump has also been repaired several times, so pump-related problems can be ruled out as well. I will come back and provide an update after replacing the check valve.
Both the inlet and the pump body have been checked and show no problems; this kind of issue is really rare. It probably has little to do with the check valve. Where is the pump outlet connected to? Could we get a process diagram to identify the cause from an operational perspective?