Problems that should be paid attention to when replacing the Water pump mechanical seal

First, preparations

1. Before replacing the mechanical seal of the water pump, carefully check whether the number of assembly seal parts is sufficient, whether the components are damaged, especially whether the dynamic and static rings have bumps, cracks and deformations. If there is a problem, repair or replacement of spare parts is required.

2. Check whether the chamfer of the bushing or gland is appropriate, if it does not meet the requirements, it must be trimmed.

3. The components of the mechanical seal of the water pump and their related assembly contact surfaces must be cleaned with acetone or anhydrous alcohol before installation. The installation process should be kept clean, especially the dynamic and static rings and auxiliary sealing elements should be free of impurities and dust. The surface of the dynamic and static rings is coated with a layer of clean engine oil or turbine oil.

Second, installation work

1. The tightening of the cap should be carried out after the coupling is aligned. The bolt should be evenly tightened to prevent the deflection of the gland section, and check each point with a feeler gauge or special tool, and its error should not be greater than 0.05 mm.

2. Check the matching gap (and concentricity) between the gland and the outer diameter of the shaft or bushing, you must ensure that the surrounding area is uniform, and check that the tolerance of each point is not more than 0.10 mm with a feeler gauge.

3. The amount of spring compression should be carried out according to the regulations, and the phenomenon of too large or too small is not allowed, and the error is required to be ± 2.00 mm, which increases the specific pressure of the section and accelerates the wear of the section. Too small will cause insufficient specific pressure and cannot play a sealing role, and the spring should move flexibly in the spring seat after installation. When using a single spring, pay attention to the direction of rotation of the spring, and the direction of rotation of the spring should be opposite to the direction of rotation of the shaft.

4. The moving ring of the mechanical seal of the water pump must be kept moving flexibly after installation, and the moving ring should be able to automatically spring back after pressing it to the spring.

5. Put the static ring sealing ring of the mechanical seal of the water pump on the back of the static ring, and then put it into the sealing end cover. Pay attention to protect the static ring section, ensure the perpendicularity of the static ring section and the center line of the end cover, and align the anti-rotation groove on the back of the static ring of the pump mechanical seal with the anti-transfer pin, but do not let it contact each other.

6. During the installation of the mechanical seal of the water pump, it is never allowed to directly knock the sealing element with a tool, and when it is necessary to knock, it must be knocked with a special tool to prevent damage to the sealing element

7. When assembling the mechanical seal of the water pump, all sealing rings should be coated with lubricants such as soapy water, which can avoid damage to the rubber rings during the assembly process. Grease is applied between the sealing surfaces of the dynamic and static rings to prevent the sealing surfaces of the dynamic and static rings from wearing out before the water pump starts.

8. When assembling the floating ring, be careful not to knock down the floating ring spring, so as not to affect the floating performance of the floating ring after the spring is knocked over. After the floating ring is assembled, you can gently press the floating ring to determine whether it has good floating performance.

9. When replacing the mechanical seal of the water pump, it should be handled with care to prevent damage to the seal, and the seal and cavity should be scrubbed clean during installation.

10. When tightening the gland of the mechanical seal of the water pump, the fastening bolt should be evenly stressed to prevent uneven force from damaging the mechanical seal. For quick-release mechanical seals, after the overall assembly, it must not be forgotten to fix the radial movement path of the positioning tabs away from the shaft.

Third, pay attention

Because the medium sealed by the mechanical seal is different, the temperature of cold water and hot water is different, whether the sealed medium is corrosive, the pressure in the chamber is different, the design of the mechanical seal will be different, and the maintenance process will be different.

Some experience has been summed up during the maintenance of the mechanical seal of the water pump: the mechanical seal should be assembled, and the cleaning inspection should not be forgotten. Look at the two rings first and then look at the shaft, and the scars and cracks should not leak. Finally, when looking at the rubber ring, the diameter of the stomata should be seen clearly. Various sizes need to be measured, and the gap between the two rings should be adjusted. The tight force must be checked, and a small spring is the key. The force of the bolt should be even, and it is a good habit to handle it gently.