If conditions permit, it is advisable to review the manufacturer’s maintenance manual and general assembly drawing for the stainless steel multistage centrifugal pump before carrying out maintenance, to identify any special points that require attention.

1. During disassembly:
2. Before dismantling the thrust bearing, use a dial gauge to measure the clearance of the balancing disc and make a record;

When disassembling a multi-stage pump, it is necessary to mark each part according to its original assembly sequence to avoid confusion and incorrect assembly during reassembly;

3. Small parts that are not easy to mark (such as keys) can be placed together with the same level of impellers or guide vanes (middle section);
4. During disassembly, you can visually inspect for any abnormal parts, such as loose fit.

II. Parts maintenance:

1. Visually inspect whether the surfaces of each part are normal, and ensure that each mating surface is free from bumps, scratches, rust, etc;
2. Use measuring tools to actually measure whether the tolerances of key mating parts are qualified;
3. Measure the clearances between the impeller sealing ring, housing sealing ring, guide vane sealing ring, interstage shaft sleeve, etc. to ensure they are within the allowable tolerance range. Replace those with excessive wear;
4. Check whether the bearing is intact;
5. It is recommended to replace all sealing rings and gaskets of the stainless steel multistage centrifugal pump with new ones.

III. Reassembly:

1. First, assemble the rotor and perform a dynamic balance test again;
2. Reassemble the parts in the reverse order of disassembly, and pay attention to measuring the clearance values at each sealing ring again during reassembly to ensure accuracy;
3. Before installing the balancing disc, measure the total axial runout of the rotor;
4. After installing the balancing disc, measure the half-row quantity of the rotor;
5. Compare with the total and half string lengths required on the manufacturer’s general assembly drawing, and ensure they basically meet the drawing requirements. Generally, the half string length is approximately half of the total string length;
6. Tighten all main bolts evenly, ensuring that they are tightened diagonally;
7. Attach a dial gauge to the shaft, rotate the shaft, and measure the balance disc. The allowable deviation should comply with the drawing requirements and generally should not exceed 0.06;

When installing thrust bearings for stainless steel multistage centrifugal pumps, attention should be paid to adjusting the clearance of the balancing disc. The adjusting ring located before the bearing should be used to adjust the clearance of the balancing disc to meet the requirements specified in the drawings.