Technical requirements for the installation of mechanical seals

Mechanical seal is a high-precision mechanical component, its correct installation and operation has a great impact on its service life. We generally follow the standards stipulated by the Ministry of Petrochemical Industry.

The technical requirements for the mating part of the pump and mechanical seal where the mechanical seal is installed are as follows:
1. Shaft curvature: maximum not more than 0.05 mm;
2. Rotor oscillation: the shaft sleeve near the sealing ring of the moving ring is not more than 0.06 mm;
3. The axial channeling momentum of the shaft is not allowed to exceed ±0.5 mm, and if it has a bushing, the sleeve is not allowed to be loose;
4. Alignment error of coupling: not more than 0.08~0.10 mm for gear coupling (P2008C), not more than 0.05~0.06 mm for elastic coupling; (customary end jump< 0.05, diameter jump <0.10）
5. The concentricity tolerance of the gland (static ring seat) and the sealing stop to the shaft centerline is 0.05 mm, and the perpendicularity tolerance of the plane in contact with the gasket to the centerline is 0.03~0.05 mm, if the requirements are not met, the sealing cavity should be processed;
6. The end of the shaft sleeve where the moving ring sealing ring is installed, and the end of the gland (or shell) where the static ring sealing ring is installed should be chamfered and smoothed.
1). Be careful when installing and disassembling the mechanical seal, and it is strictly forbidden to use a hand hammer and a flat shovel to avoid damaging the sealing elements. If the scale cannot be disassembled, it should be cleaned before disassembly.
2). If both ends of the pump are mechanically sealed, take care of each other during the assembly and disassembly process to prevent one from losing the other.
3). For the running mechanical seal, where the gland is loose and the seal moves, the dynamic and static ring parts must be replaced, and should not be re-tightened and continue to be used. Because the original running trajectory of the friction pair will change after loosening, the sealing of the contact surface is easily damaged.