How To Maintain The Packing Seal Of A Single-stage Centrifugal Pump

Oct 12, 2025

The packing seal of a single-stage centrifugal pump is an important part of the sealing effect, so it is necessary for users to master its maintenance methods, so that when the packing seal of the single-stage centrifugal pump fails, it can be dealt with in a timely manner, so as not to affect the normal operation of the pump. The following is an introduction to the packing seal maintenance methods of single-stage centrifugal pumps.

 

1. Clean the packing box of the centrifugal pump and inspect the shaft surface for scratches, burrs, etc. The packing box should be cleaned thoroughly, and the shaft surface should be smooth.

2. Check the shaft runout, and ensure that the unbalance of the rotor runout is within the allowable range to avoid excessive vibration that may be detrimental to the packing.

3. Apply sealant or lubricant suitable for the medium inside the packing box and on the surface of the shaft.

4. For the filler packaged in rolls, first take a wooden stick with the same size as the shaft neck, wrap the filler around it, and then cut it with a knife, preferably with a 45 ° slope.

 

 

5. The filling material should be filled one by one, not several at a time. The method is to take a piece of filler, apply lubricant, hold one end of the filler interface with both hands, pull it apart along the axis to form a spiral shape, and then insert it into the shaft neck through the incision. Do not pull apart radially to avoid uneven interfaces.

6. Take a metal shaft sleeve of the same size and material as the packing box or with a lower hardness than the shaft, push the packing into the deep part of the box, and apply a certain pressure to the shaft sleeve with a cover to pre compress the packing. The pre compression shrinkage is 5% to 10%, with a maximum of 20%. Rotate the shaft again and remove the shaft sleeve.

7. Using the same method, load the second and third tubes. Note that when the number of fillers is 4-8, the interfaces should be staggered by 90 degrees during loading; Two fillers staggered by 180 °; 3-6 pieces should be staggered by 120 ° to prevent leakage through the interface.

8. After the last packing is filled, it should be compressed with a pressure cap, but the compression force should not be too high. Simultaneously rotate the shaft by hand to make the assembly clamping force tend towards a parabolic distribution. Then relax the cover slightly.

 

 

9. Conduct a running test, and if it cannot be sealed, tighten some packing material; If the heat is too high, relax it a bit. Only when the temperature of the filling part is only 30-40 ℃ higher than the ambient temperature, can it be officially put into use when it is adjusted to only have a droplet like leakage and not generate much heat.

The above is the maintenance method for the packing seal of a single-stage centrifugal pump. In addition, when repairing or replacing the mechanical seal of the packing seal of a single-stage centrifugal pump, there is no need to disassemble the motor and pump cover.