The problem of excessive vibration at the water pump inlet and the inlet valve
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Hello everyone. Our fire water system is equipped with three fire pumps, which are single-stage vertical centrifugal pumps. Their inlets are connected to the water tank. At first, everything worked fine, but after some time, the inlet pipes and valves of two of these pumps started vibrating severely, while the third pump had no problems. There is a support below the gate valve; the two inlet pipes with high vibration levels are located at approximately 3 meters distance, while the other one is at about 5-6 meters distance. I’m considering that there are differences in the length of the pipes imported, but they generally meet the requirements of 5D. Is it due to a lack of pipe supports, or what’s the reason? The manual suggests using imported flexible connectors; I’m not sure if that makes a difference I don’t know what the reason is? Let’s discuss it together.
Generally, when installing a water pump, we pour a new cement foundation for the base. If the foundation is not completely dry before the equipment is put into operation, over time the vibration of the entire equipment will cause the foundation to vibrate as well, which in turn causes the pipes and valves connected to the pump to vibrate. To prevent this from happening, it is generally recommended to install flanged rubber expansion joints at both the inlet and outlet of the pump; this helps to eliminate vibrations in the pipes and valves, as well as to reduce stress in the pipes.
It shouldn’t be due to fundamental issues; the first and second grouting operations, shaft alignment, and levelness are all good, and the water pump itself operates steadily with no vibrations. The flow rate is 1,100 cubic meters, with the inlet pipe having a DN500 diameter. Is this related to the water tank’s suction inlet? It was inspected by cutting it open during maintenance, and no blockages were found.
We have also encountered the problem of excessive vibration in the water pump. Now, flexible connectors have been installed at both the inlet and outlet of the pump, and the vibration in the pipes has indeed decreased. If the vibration in the pump remains high, it will likely be necessary to check whether the foundation on which the pump is mounted is level~
Analysis of pipeline vibration causes: 1. Unstable fluid flow. 2. Reaction of the pump.
Severe cavitation in the pipeline or a loose pump foundation.
See the comments below to find out the reason. The cavitation problem can be resolved by replacing the pump or modifying the inlet pipeline ； Design remedies for basic issues.
It operates normally; vibration occurs after some time, using room temperature water. Go and tighten all the flanges on the inlet pipelines