Basic terms and definitions:

Seal: refers to the phenomenon that there is no leakage at the joint of the machine or equipment;

Leakage: The main reason for the leakage of the seal caused by the transfer of materials through the seal: 1. Installation gaps caused by surface defects of mechanical parts, dimensional processing errors and installation errors; 2. There is a pressure difference on both sides of the seal. Reducing or eliminating the installation gap is the main way to prevent leakage;

Sealing force (or sealing load): the contact force acting on the seal of the contact seal;

Contact pressure: the force between the friction surfaces of the packing seal;

Packing: a component installed between the movable rod and the hole through which it passes on the equipment or machine to seal the medium;

Compression packing: a packing with a soft texture, which is axially compressed in the stuffing box and undergoes radial elastic deformation to block the gap;

Compression rate: the compression deformation rate caused by the compression deformation of the cross section of the sealing ring when it is installed in the sealing groove;

Static seal: the seal between relatively static cooperative surfaces , the function of sealing is to prevent leakage;

Dynamic seal: refers to the seal between moving parts in machines or equipment;

Contact seal: uses sealing force to press the seal and the mating surface against each other or even embed them to reduce or eliminate the gap;

Packing seal: the seal of the packing as a seal;

Sealing gasket: a thin-section seal placed between the mating surfaces that meets the requirements. According to the material, it can be divided into: rubber gasket, metal gasket, paper gasket, asbestos gasket, plastic gasket, graphite gasket, etc.;

Sealing ring: a ring-shaped seal used to prevent the medium from leaking from the sealing device and to prevent foreign matter and air from entering the sealing device;