Packing seal refers to a dynamic sealing device that generates a pressing force between the packing and the rotating member and the fixing member by self-tightening of the pre-tightening or medium pressure.
It has many structural forms and is mainly composed of packing, stuffing box and packing fixing parts. Commonly used filler materials are asbestos fabric, carbon fiber, rubber, flexible graphite and engineering plastics, etc., pre-formed into rings or strips (some need pre-impregnated lubricated fillers), and multi-ring or spiral multi-layer structure.
The stuffing box is used to place the packing. The packing fixtures include a gland, bolts and springs to pre-tighten the packing, prevent leakage of the medium during operation, and the spring can compensate.
Material properties
1 has a certain flexibility. Under the action of the pressing force, a certain radial force can be generated and closely contact with the shaft.
2 has sufficient chemical stability. Without contaminating the medium, the filler is not swollen by the medium, the impregnating agent in the filler is not dissolved by the medium, and the filler itself does not corrode the sealing surface.
3 self-lubricating performance is good. Wear resistance and friction coefficient are small.
There is a small amount of eccentricity in the 4 axis, and the packing should have sufficient floating elasticity.
5 Easy to manufacture and easy to load.
