To make matters worse, another pump has developed a problem. I would appreciate it if all the experts could help analyze this issue. Thank you!
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The customer sent a water pump for repair; due to excessive vibration levels, it was necessary to carry out a thorough overhaul and re-establish dynamic balance. Balance disc, balance drum for vehicle lighting; additional shims to compensate for machining variations. Replace the mechanical seal and bearings. Overall dynamic balance. After the major repair, the customer’s actual operation was stable and normal; after running steadily for a week, it is planned to shut down for maintenance. The main pump was used again. The leakage from the main pump is becoming increasingly severe, and the customer plans to use the backup pump while the main pump is repaired. As a result, the standby pump no longer performed as it did during the testing week; its vibration levels were significantly high, exceeding 7. Here’s the question: why did it work fine for a week, but started having problems once it was stopped and used again? Where should I start checking? Thank you to all the teachers! Pressure 3Mpa, head 300 meters, speed 2950rpm
I’d like to talk about the fan, in the hope that it will be helpful to you. This fan is an exhaust fan located after the absorption tower; it’s made of carbon steel. The gas being absorbed is acidic, and after the absorption tower removes these acidic gases, they enter the fan and are then discharged. One day, the circulation pump of the absorption tower wasn’t operating, but the fan continued to run, and it functioned properly with no issues detected. Due to some other reasons, the system was shut down for a few days; when it was restarted, the fan started vibrating severely. After opening it, it was found that the impeller was severely corroded. The reason is that during operation, the degree of corrosion of the impeller is the same, so no eccentricity occurs. After shutdown, the impeller stops rotating, and as a result the degrees of corrosion vary, causing the impeller to become eccentric and leading to severe vibration during operation.
The focus of the inspection should be on whether the production medium and the pump are suitable for use, and whether their operation is proper. Another aspect is whether the installation of the foundation and the pump body is proper, whether there is any poor bonding, including the levelness, whether the bolts are tightened with sufficient preload (due to limitations imposed by the threads), and the quality of the secondary grouting. Oh, and there are also process-related issues, such as valve leaks. . . . . .
Pay special attention to checking whether there are any issues with the lubrication of the bearings~~~~ Examine the fit between the inlet rings of each stage of impellers and those of the casing, as well as whether there is any loosening~~~~ Check the fixation of the balance disk, its clearance value, and whether there are any foreign objects present...........
The phenomenon you mentioned is very likely caused by medium crystallization
1. Use SPM to measure the specific vibration spectrum to determine what harmonic it is. 2. Check whether there is a possibility of slow scaling in the process medium, considering the condition when it was first returned to the factory. 3. After disassembly, examine the fit and wear of various components, and also check whether the pump foundation is loose
After the pump stops operating, it should be rotated regularly to prevent the rotor from bending as well as dynamic imbalance caused by the properties of the medium
Agree with the view from floor 7; since the vibration is high, it is recommended to first measure the spectrum to see what harmonic frequencies are the dominant ones.
Check for any changes in the process conditions, or use another pump of the same type to rule out whether the issue lies with the equipment or the process.
Is there any problem with the pump foundation? Is there a problem with the bearing housing itself?