Mechanical seals are high-precision mechanical components, and their correct installation and operation have a significant impact on their service life. We generally follow the standards set by the Ministry of Petrochemical Industry. The technical requirements for the installation of mechanical seals in pumps and their mating parts are as follows: Mechanical seals are high-precision mechanical components, and their correct installation and operation have a significant impact on their service life. We generally follow the standards set by the Ministry of Petrochemical Industry. The technical requirements for the installation of pumps with mechanical seals and the coordination of mechanical seals are as follows:

1. Axis curvature: maximum not exceeding 0.05 millimeters;

2. Rotor oscillation: not more than 0.06 millimeters near the shaft sleeve at the sealing ring of the dynamic ring;

3. The axial displacement of the shaft is not allowed to exceed ± 0.5 millimeters. If there is a shaft sleeve, it is not allowed for the shaft sleeve to become loose;

4. The alignment error of the coupling: for toothed couplings, it should not exceed 0.08-0.10 millimeters (P2008C), and for elastic couplings, it should not exceed 0.05-0.06 millimeters; (Habitual practice: end jump<0.05, radial jump<0.10)

5. The concentricity tolerance of the sealing fitting joint between the gland (static ring seat) and the shaft centerline is 0.05 millimeters, and the perpendicularity tolerance of the plane in contact with the gasket to the centerline is 0.03-0.05 millimeters. If the requirements are not met, the sealing chamber needs to be processed;

6. The end of the shaft sleeve for installing the dynamic ring seal and the end of the gland (or housing) for installing the static ring seal should be chamfered and smoothed.

7. Be careful when installing and disassembling mechanical seals, and it is strictly prohibited to use hammers and flat shovels to avoid damaging the sealing components. If scaling cannot be removed, it should be cleaned thoroughly before disassembly.

8. If mechanical seals are used at both ends of the pump, take care of each other during assembly and disassembly to prevent neglecting one aspect.

9. For the mechanical seal that has been operated, if the cover is loose and causes the seal to move, the dynamic and static ring parts must be replaced and should not be tightened again to continue use. Because the original operating trajectory of the friction pair will change after loosening, the sealing performance of the contact surface is easily damaged.

Key points for using seals

Seals are materials or components that prevent fluid or solid particles from leaking between adjacent bonding surfaces and prevent external impurities such as dust and moisture from entering the interior of machinery and equipment

(1) Choose appropriate sealing material and hydraulic oil, as well as adaptability to working temperature and compatibility with oil.

(2) The geometric position accuracy (concentricity) of the sliding parts relative to the seal is high, and the material is good (such as hard chrome plating) and the surface roughness is fine, which can extend the service life.

① For the oil seals used in hydraulic pumps and motor shaft necks, it is not only required that the roughness of the sliding surface be within 0.25m Ra, but also that the surface be plated with hard chromium. In specific use, the radial spring force of the oil seal lip needs to be adjusted appropriately according to the specific situation to make it moderately tight. In addition, a mounting sleeve or thin gasket should be used to protect the sealing ring during installation to prevent the lip from curling or twisting, causing the spring to slide out.

② The commonly used rolling processing method for the inner surface of hydraulic cylinder barrel not only improves the surface roughness, but also conducts cold work hardening treatment on its surface, which is beneficial for extending the service life of the sealing ring. In addition, the pressure used, the length and type of sliding surface also have a significant impact on the service life. Therefore, the scheduled inspection time should be determined based on these conditions.

③ Require good lubrication of the sealing surface to prevent dirt from entering. It is also necessary to use oil that meets the prescribed cleanliness level and use the correct installation method.