New pump test run issues
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This post was last edited by Pharaoh on 2019-5-31 07:54. Our company has a new pump, the pump model is DY46-50* 6A, the following problems occurred during test run: On April 1, the team switched to P302/A operation and found that the pump vibrated greatly. They contacted the fitter to measure the vibration and found that the front bearing was level.: 6.5, the rear bearing level is 8.8, both exceeding the standard value specified by the manufacturer, and there is slight leakage in the front seal. On the 8th, the manufacturer and the fitter were contacted to find the cause of the large vibration of P302A. The manufacturer recommended replacing two sets of seals first. On the 9th, the seal replacement was completed. On the 10th, the P302/A was started to run, and the level The vibration remained at around 6.4. On the 11th, the vibration value rose to 7.5 in the afternoon, and the pump was switched to B pump operation. On the 15th, the P302A manufacturer arranged for technicians to come to the scene to deal with the major vibration problem of the pump. The pump was disassembled and overhauled. After disassembly, the data was measured and it was found that the main reason for the large vibration was: The shaft is bent and deformed, the maximum runout exceeds 23 steps, and the interstage bushing has signs of wear. The main shaft and interstage bushing need to be replaced. On May 14, the P302/A spindle and other accessories arrived. The manufacturer arranged for technicians and fitters to replace the accessories, and all data tested qualified. On the 17th, after the P302/A spindle, balance plate, interstage sleeve, top sleeve, bearings and other accessories were reassembled, the test machine pump showed no leakage and the vibration value passed the test. ； On the 20th, I switched to pump A and ran it for about ten minutes. It was found that the front-end seal was leaking. I stopped for inspection and found that it was difficult to turn the pump. I contacted the fitter and the manufacturer to disassemble and inspect the machine. It was found that the 2nd and 3rd stage sleeves and the impeller mouth ring were seriously worn. ； On the 21st, the hardness of the relevant spare parts was inspected, and the inspection results showed that the interstage sleeve hardness was HB.: Around 100-130, which is lower than the manufacturer’s design requirements and requires the fitter to re-process it. ； On the morning of the 23rd, the interstage sleeve was processed, and the data inspection and reassembly were carried out in the afternoon. On the 24th, the P302/A was reassembled, and the cranking jammed again. After disassembling the rear end, it was found that the balance plate and balance seat had signs of wear. The balance plate gap was adjusted from the original 7 lanes to 13.4 lanes. The cranking was normal. On the 25th, the test run was carried out. The front and rear bearings The vibration value was normal and the sealing was normal. After running for about 2 hours, the temperature of the rear-end bearing continued to rise to 69°C and the car was stopped. On the 27th, the P302/A rear-end balance plate gap was adjusted to 10 lanes. On the afternoon of the 28th, after driving for one hour, the temperature of the rear-end bearing continued to rise to 60°C. The car was stopped and the car was still stuck when turning again. What's wrong with the pump?
Get a self-balancing multi-stage pump.
Should the vibration be replaced first? Talent
Let me help you smooth it out: Our company has a new pump, the pump model is DY46-50 * 6A, the following problems occurred during test run: On April 1, the team switched to P302/A operation and found that the pump vibrated greatly. They contacted the fitter to measure the vibration and found that the front bearing was level.: 6.5, the rear bearing level is 8.8, both exceeding the standard value specified by the manufacturer, and there is slight leakage in the front seal. On April 8, the manufacturer and the fitter were contacted to find the cause of the large vibration of P302A. The manufacturer recommended replacing two sets of seals first. On April 9-10, the seal replacement was completed, and the P302/A operation was started, and the horizontal vibration was maintained at around 6.4. On April 11, the vibration value rose to 7.5 in the afternoon, and the switch was switched to B pump operation. On April 15, the P302A manufacturer arranged for technicians to arrive on site to deal with the problem of large vibration of the pump. They disassembled and overhauled the pump. After disassembling the machine, they conducted data measurements and found that the main cause of the large vibration was: The shaft is bent and deformed, the maximum runout exceeds 23 steps, and the interstage bushing has signs of wear. The main shaft and interstage bushing need to be replaced. On May 14, the P302/A spindle and other accessories arrived. The manufacturer arranged for technicians and fitters to replace the accessories, and all data tested qualified. On May 17, after the P302/A spindle, balance plate, interstage sleeve, top sleeve, bearings and other accessories were reassembled, the test machine pump showed no leakage and the vibration value passed the test. ； On May 20, I switched to pump A and ran it for about ten minutes. It was found that the front-end seal was leaking. I stopped for inspection and found that turning was difficult. I contacted the fitter and the manufacturer to disassemble and inspect the machine. It was found that the 2nd and 3rd stage sleeves and the impeller mouth ring were seriously worn. ； On May 21, the hardness of the relevant spare parts was inspected, and the inspection results showed that the interstage sleeve hardness was HB.: Around 100-130, which is lower than the manufacturer’s design requirements and requires the fitter to re-process it. ； On the morning of May 23, the interstage sleeve was processed, and the data inspection and reassembly were carried out in the afternoon. On May 24, P302/A was reassembled, and the cranking jammed again. After disassembling the rear end, it was found that there were signs of wear on the balance plate and balance seat. The balance plate gap was adjusted from the original 7 lanes to 13.4 lanes, and the cranking was normal. The test run on May 25 found that the vibration value of the front and rear bearings was normal and the sealing was normal. After running for about 2 hours, the temperature of the rear-end bearing continued to rise to 69°C and the car was stopped. On May 27, the P302/A rear-end balance plate gap was adjusted to 10 lanes. After driving for one hour in the afternoon of May 28, the temperature of the rear-end bearing continued to rise to 60°C and the car was stopped. The car still had jamming when turning again. What's wrong with the pump?
1. The wear of the mouth ring and the interstage sleeve is not the main cause. The main cause is the insufficient rigidity of the shaft, which causes the shaft to bend and the vibration to exceed the standard. Whether the cause of the shaft bending is poor balance of the impeller needs to be investigated. 2. When the vibration of the pump reaches 6-7mm/s, why is it still being used? Doesn’t the instruction manual indicate that when XX exceeds the standard, does it need to be stopped immediately for inspection? 3. The shaft bending vibration exceeds the standard. Why not check and find out the cause of the vibration, but only replace the seal? Will the seal cause the vibration to exceed the standard? 4. What is the balance plate gap value required in the instruction manual? How can you say that it is just an adjustment? The adjustment is so large, from 0.07mm to 0.134mm. What is the basis? Is it a rough estimate, rich experience, documented guidance, or calculation? 5. After adjusting the balance plate gap, the axial force is very large and the bearing heats up seriously. Why is the balance gap adjusted to 0.1mm? What is the basis? 6. If the hardness is not up to standard, it is not recommended to replace the shaft with a material with higher strength and stiffness. Can the shaft size and structure be adjusted to increase stiffness and reduce deformation?
This post was last published by Flying Snail on 2019-5-30 08:51 What is the editing medium? Please provide the information about the pump as well.
Personally, I think there is something wrong with the force balance of the pump. Is the impeller worn?
personal opinion: There should be a problem with balancing the axial force. You should pay attention to the balance plate gap and whether there is air in the medium.
Whose pump is it? What is the flow head when it is turned on? Is it moving at a small flow rate? If the balance plate heats up but does not vibrate, it may be a problem with the pump accuracy or assembly or installation. A gap of 7 is normal and there will be no problem. There are many reasons for the vibration of multi-stage pumps, which need to be looked at comprehensively.
The balance device wears out quickly, which means there is a problem with the axial force balance.
Insufficient structural rigidity, check dynamic balance. This pump should never have come out of the factory.