Maintenance method of centrifugal pump parts

1、 Maintenance method of packing seal
1. Clean the stuffing box of the sewage pump and check the shaft surface for scratches, burrs, etc. The stuffing box shall be cleaned and the shaft surface shall be smooth.
2. Check the shaft runout. The unbalance of the rotor runout should be within the allowable range to avoid excessive vibration, which is harmful to the packing.
3. Apply sealant or lubricant suitable for the medium to the stuffing box and shaft surface.
4. For the packing packed in rolls, first take a wooden stick with the same size as the journal, wind the packing on it, and then cut it with a knife. The knife edge is 45 ° inclined.
5. Fillers shall be filled one by one, not several at a time. The method is to take a piece of packing, apply lubricant, hold one end of the packing interface with both hands, pull it away along the axial direction to make it spiral, and then put it into the journal from the incision casing. It shall not be pulled apart along the radial direction to avoid uneven interfaces.
6. Take a metal shaft sleeve with the same size and material as the packing box or with lower hardness than the shaft, push the packing into the deep part of the box, and apply a certain pressure on the shaft sleeve with the gland to make the packing precompressed. The pre compression shrinkage is 5%~10%, up to 20%. Rotate the shaft for another circle and take out the shaft sleeve.
7. Fill the second and third root in the same way. Note that when the number of fillers is 4-8, the interfaces shall be staggered by 90 °; Two fillers are staggered 180 °; 3~6 pieces shall be staggered by 120 ° to prevent leakage through the interface.
8. After the packing is completed, the gland shall be used for compaction, but the compaction force shall not be too large. At the same time, rotate the shaft by hand to make the assembly pressing force tend to parabola distribution. Then loosen the gland slightly.
9. Carry out operation test. If it cannot be sealed, compress some packing; If the heat is too high, relax it. In this way, it can only be put into use when the leakage is in the form of drops and the heat is not too high (the temperature of the packing part can only be 30~40 ℃ higher than the ambient temperature).
Technical requirements for packing seal assembly of centrifugal pump. The installation of packing seals shall comply with the provisions of the technical documents. If not specified, the following requirements shall be met:
1. Check the radial runout of the shaft at the sealing parts, and the allowable radial runout of the shaft is within 0.03~0.08mm;
2. The diameter clearance between the liquid seal ring and the shaft sleeve is generally 1.00~1.50mm, and the diameter clearance between the liquid seal ring and the stuffing box is generally 0.15~0.20mm;
3. The diameter clearance between the packing gland and the shaft sleeve is generally 0.75~1.00mm, and the clearance around shall be uniform;
4. The diameter clearance between the packing gland and the stuffing box is generally 0.10~0.30mm;
5. When there is a packing bottom ring, the diameter clearance between the bottom ring and the shaft sleeve is generally 0.70~1.00mm;
6. After the packing is compressed, the liquid inlet hole of the liquid seal ring shall be aligned with the liquid seal pipe, or the liquid seal ring is slightly inclined to the outside;
7. For the packing in rolls, first take a wooden stick with the same size as the shaft, wind the packing on it, and then cut it with a knife. The cut is 45 ° inclined.

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