Regarding the issue of excessive bearing temperature during the testing of centrifugal pumps
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During the acceptance testing of a batch of centrifugal pumps in accordance with API610, it was found that in 3 of the vertical centrifugal pumps, one of them reached a maximum bearing temperature of 74 degrees after operating for half an hour； The maximum temperature of the bearings in the other two units also reached around 65 degrees ； The technical agreement between the two parties stipulated that the applicable standard was API, with the rated temperature not exceeding 80 degrees or the ambient temperature plus 40 degrees. Based on these requirements, the ambient temperature at that time was around 10 degrees above zero; as a result, all three pumps failed to meet these conditions and were rejected by the third party. However, after consulting API610 version 11, no specific temperature rise value specified for greasing vertical centrifugal pumps was found. Later, bearings were replaced on all 3 pumps, but the problem remained unresolved. Therefore, I ask some expert to provide an answer. Thank you!
The lubrication method of the bearing is correct; if grease is used for lubrication, an excess amount of grease or uneven distribution of it will cause the bearing temperature to be slightly higher in the initial stage. After 1 hour of operation, the temperature generally stabilizes. When powered on again, the bearing temperature may drop.
I would like to ask: The technical agreement states that the applicable standard is API, with the rated temperature not exceeding 80 degrees or the ambient temperature plus 40 degrees. ”What is the basis for this rule? Why do I feel that it’s completely inconsistent when compared to the provisions of API 610 (5.10.2, Version 10.4)? If the design institute cannot provide an explanation, it is recommended to follow the manufacturer’s QA regulations. Generally, before the product leaves the factory, the IOM manual is already provided to the designers; one should check what the alarm values and shutdown values are specified in that manual, and proceed according to those standards. Of course, the prerequisite is that the manufacturer should be at least a first-class pump factory in the country (such as Dalian Shenlan, Liohua Neng, Shenyang Industrial Pump, or Zhejiang Keer),; it would be a disaster to work with a second-rate or even third-rate pump manufacturer.
Turn it for a bit longer to see if the temperature continues to rise; after just half an hour, I found the high temperature to be a bit inappropriate.
What about the vibration and lubrication conditions? What is the current temperature of the medium? Are there any unusual noises? Since new bearings have been installed, have the old bearings shown signs of wear or uneven wear? It is recommended to run the equipment for a while longer to see if the temperature continues to rise; new equipment requires a running-in period.