Axial displacement of centrifugal compressors
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Condition: 1. The axial play measured with a depth gauge before disassembly was 0.4 mm. 2. Condition of the non-driving side: two thrust bearings and one support bearing. 3. After the thrust bearings are installed (with their upper caps not yet in place), the shaft can shift by 1.3 mm; however, this amount decreases to 0.1 mm once the caps of the thrust bearings are installed. 4. The thrust disc of this compressor is fixed to the shaft using a long nut, and two small set screws are located at the ends to prevent the nut from rotating. The nut is not very tight when it needs to be removed – it can be loosened by giving it a quick hit with a hammer. 5. Both the thrust bearings and the support bearings were removed for flaw detection; one employee from a maintenance company was responsible for carrying out this inspection, so there should be no chances of incorrect installation. I’m not sure why the overall axial movement doesn’t meet the required level (the normal value is 0.2–0.5 mm). I hope experts can suggest some solutions; thank you very much!
1. What type of thrust bearing shell? Is Michelle still in the Kingsbury form? 2. Have the tiles been replaced? 3. The thrust clearance has decreased – where is there restriction? If the unit cover is removed, it should be possible to see 4. What is the structure of the bearing housing? Is it integrated with the unit housing?
1. The thrust pads are of the Kinsberley type. 2. The pads have not been replaced, but they were removed for flaw detection at one time. 3. The reduction in thrust clearance is due to the bearings not being installed properly after flaw detection; this is the key to this issue. 4. The bearing housing is separable from the unit casing.