How can the problem of increased vibration in this centrifugal pump be solved?
Thread Content
This post was last edited by HLBO on 2024-7-22 at 20:24. There is a set of OH2 centrifugal pumps on site, one in use and one as a backup. When Pump A starts, even if Pump B does not start, the vibrations transmitted through the pipelines can cause the pump to vibrate at around 2.0 mm/s. Measurements taken on the pipeline at the pump’s outlet showed vibrations of around 2.0 mm/s 1 meter away from the outlet; these vibrations increased as one moves towards the check valve, reaching around 3.5 mm/s at the check valve. After passing the check valve, the vibrations gradually decreased, dropping to 1.8 mm/s at the flange in front of the outlet valve. (All values refer to horizontal vibrations; vertical vibrations are relatively lower, probably due to the support structures in place.) It was checked that all the supports at the outlet were secure, and shims were also used to reinforce them. Based on the above assessment, I believe the problem is the vibration of the pump caused by vibrations at the outlet. However, there are two points I don’t quite understand: 1. Why is the vibration highest at the check valve, rather than increasing as one moves towards the tee connecting pumps A/B or towards pump B? Is there a problem with the check valve? 2. How to solve it? Can the problem be solved by adding more horizontal pipeline supports?
Based on your description, it is indeed possible that the vibration from the outlet pipeline is causing the vibration issues in the entire set of pumps. Regarding the questions you raised and the proposed solutions, one can think about it as follows: 1. **Reason for the highest vibrations at the check valve**: - It may be due to the structure or function of the check valve itself, which causes turbulence or backflow of fluid as it passes through, increasing the instability of the fluid dynamics and thus leading to increased vibrations. Furthermore, if the check valve does not close properly or is damaged, it will also lead to significant changes in fluid dynamics, causing substantial vibration. - The check valve may also possess a mechanically inherent resonance point, where the system’s natural vibration frequency matches the excitation frequency caused by the flow, leading to vibration amplification. 2. **Solution**: - **Check and repair the check valve**: First, it is necessary to verify that the check valve is functioning properly, with no leaks or damage. Replace or repair the check valve if necessary. - **Strengthen pipeline support**: Although the outlet support is already quite sturdy, it may be advisable to add additional supports or vibration-damping measures in areas with high vibration levels (especially near the check valves). This can include the use of devices such as dampers or vibration-absorbing pads. - **Optimize pipeline layout**: Examine the current pipeline layout, especially those near check valves, to identify any excessive bends or unreasonable turns that could serve as sources of vibration. Try to optimize the pipeline layout by reducing bends and unnecessary pipe lengths. - **Dynamic balance testing and adjustment**: Conduct dynamic balance tests on the pump and piping systems to identify and address any factors that may cause imbalance. - **Monitoring and analysis**: Install vibration monitoring equipment to continuously track vibration data, analyze the frequency and amplitude of vibrations, so as to scientifically determine whether the measures taken are effective and to adjust response strategies in a timely manner. Through the above measures, the vibration problems of centrifugal pumps and their piping systems can be effectively resolved, ensuring the stable operation of the system. .
Check the check valve disc; try replacing it with a new valve or using a different type of check valve
It’s likely that the check valve is faulty – it hasn’t opened fully, which results in pressure buildup
It is recommended to check whether the check valve cannot open fully