Mechanical seal is a mechanical component with high precision, and its correct installation and operation have a great impact on its service life. We generally follow the standards set by the Ministry of Petroleum and Chemical Industry. The technical requirements of the pump and mechanical seal matching part for installing mechanical seals are as follows: mechanical seals belong to high precision mechanical parts, and their correct installation and operation have a great impact on their service life. We generally follow the standards set by the Ministry of Petroleum and Chemical Industry. The technical requirements for the matching part of the pump and the mechanical seal installed with the mechanical seal are as follows:

1. Axis curvature: maximum not more than 0.05 mm;

2. Rotor oscillation: not more than 0.06mm near the sleeve at the seal ring of the moving ring;

3. Axial displacement of axle should not exceed (+0.5 mm). If the axle sleeve is with axle sleeve, the axle sleeve should not be loosened.

4. The alignment error of the coupling: for the gear coupling not more than 0.08-0.10 mm (P2008C), for the elastic coupling not more than 0.05-0.06 mm; (customary end jump < 0.05, diameter jump < 0.10)

5. The concentricity tolerance of the cover (stationary ring seat) and the sealing joint to the axis center line is 0.05 mm, and the perpendicularity tolerance of the plane contacting the gasket to the center line is 0.03-0.05 mm. If the requirement is not met, the sealing cavity should be processed.

6. The end of the sleeve with dynamic ring seal ring and the end of the cap (or shell) with static ring seal ring should be chamfered and smoothed.

7. Be careful when installing and disassembling mechanical seals. It is strictly forbidden to use hammers and flat shovels in order to avoid damaging sealing elements. If scaling can not be removed, it should be cleaned before disassembly.

8. If mechanical seals are used at both ends of the pump, they should take care of each other during assembly and disassembly so as to prevent one from losing sight of the other.

9. For mechanical seals that have been operated, if the cover is loosened and the seal moves, the dynamic and static ring parts must be replaced, and should not be tightened again to continue to use. Because the original trajectory of the friction pair will change after loosening, the sealing of the contact surface will be easily destroyed.

Key Points for Use of Seals

Seals are materials or parts that prevent fluid or solid particles from leaking from adjacent joints and external impurities such as dust and moisture from intruding into the internal parts of machinery and equipment.

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

(2) Geometric position accuracy (concentricity) of sliding parts relative to seals, high quality (such as hard chromium plating) and fine surface roughness can prolong service life.

(1) For the oil seals used in the journals of hydraulic pumps and motors, not only the roughness of the sliding surface should be less than Ra 0.25m, but also the hard chromium plating on the surface of the oil seals should be required. The radial spring force on the lip side of the oil seals should be adjusted appropriately according to the specific conditions so as to make them loose and moderate, and a sleeve or thin pad should be installed. The sheet protects the sealing ring so as not to roll and twist the lip edge and cause the spring to slip out.

(2) The common rolling method for the inner surface of hydraulic cylinder not only improves the surface roughness, but also hardens the surface, which is beneficial to prolong the service life of the sealing ring. In addition, the pressure used, the length and type of sliding surface also have a great impact on the service life. Therefore, the inspection time should be determined according to these conditions.

(3) Require the sealing surface to be in good lubrication condition and prevent dirt intrusion. It is also necessary to use oil that reaches the specified cleaning level and correct installation method.