Abnormal noise from high-speed pump
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High-speed pump; abnormal noise at the high-speed shaft drive end; the bearings were replaced just a couple of days ago. The replaced bearing had pitting. Today, abnormal noises appeared again; the high-speed shaft drive end experienced vertical vibration at 3.5 mm/s, horizontal vibration at 2.2 mm/s, and axial vibration at 15 mm/s (with instability). Vibration of the low-speed shaft bearing: 1.9 mm/s. The temperature is 35°C everywhere. What causes this, please?
What are the key points for this repair?
The high-speed pump is making abnormal noises, and the replaced bearing has pitting, indicating mechanical wear or damage. Considering the vibration data you mentioned, especially the fact that the axial vibration has reached 15 mm/s and is unstable, this may indicate a fairly serious problem with the pump. Here are some possible causes of such problems: 1. Bearing installation issues: If the bearings are not installed correctly, it may lead to excessive vibration and unusual noises during operation. During installation, it is necessary to ensure that the concentricity and levelness of the bearings meet the specifications. 2. Bearing damage: The replaced bearing having pitting may be due to uneven loading on the bearing, or corrosion or contaminants entering it. 3. Improper bearing selection: If the selected bearing is not suitable for operation at high speeds, or if the load calculation is inaccurate, the bearing may be damaged in a short period of time. 4. Bending or misalignment of the shaft: Improper alignment of the mechanical shaft or bending of the shaft can also lead to uneven bearing load distribution, thereby causing abnormal vibrations and noises. 5. Soft-footing phenomenon: An unstable or uneven base or mounting platform for the pump can cause additional vibration during operation. 6. Insufficient lubrication: Lack of lubrication can cause the bearings to overheat and wear, resulting in abnormal noises. 7. Dynamic balance issue: If the impeller of a pump or its key rotating components are out of balance, vibrations and noise can occur during high-speed rotation. 8. Operating condition issues: If the pump’s design or operating conditions (such as flow rate and pressure) exceed the standard operating parameters, this can also lead to such problems. To accurately diagnose the problem, it is recommended to carry out the following actions: – Check the pump’s mounting base to confirm that it is secure and level. - Check the alignment of the shaft and bearings. - Check the dynamic balance of the impeller and other rotating components. - Ensure that the bearings are properly lubricated, using the appropriate lubricant or grease, and replace or top it up at regular intervals as specified. - Check whether the operating parameters of the pump meet the design specifications. - If necessary, consult the manufacturers of the pump and bearings to find out if there are any known issues or suggestions for improvements. - If the problem persists, consider having a professional mechanical engineer or repair technician conduct a diagnosis. Please keep in mind that continuous high vibration levels are harmful to the health of equipment, and can lead to premature aging or failure of the equipment. Therefore, the root cause of the problem should be identified and resolved as soon as possible. .
Are both axes properly positioned? Is the axial play set?
Imbalance; shaft bending can cause high axial vibration
This post was last edited by CHANGBAISHI on 2023-12-12 07:02. The likely cause of this phenomenon is the presence of impurities in the light oil. It is recommended to check whether the gearbox is clean, and to clean the bottom and surrounding areas of the gearbox. Using dough generally yields a better sticking effect. Impurities introduced during installation must be strictly monitored. This is common in this area, such as wearing fiber gloves or failing to clean the components before installation. The installation quality must meet the standards; the required specifications for each component must be followed as specified in the instructions. For reference.
Check in accordance with the maintenance procedures provided by the equipment manufacturer; reference can be made to SHS 01035 \"Maintenance Procedures for High-Speed Pumps\"