Leakage is one of the common failures of mechanical equipment. There are two main reasons for the leakage: First, due to mechanical processing, the surface of mechanical products must have various defects and deviations in shape and size, so gaps will inevitably occur at the joints of mechanical parts; If there is a pressure difference on the side, the working medium will leak through the gap.
Seals can be divided into two categories: static seals between relatively stationary joints and dynamic seals between relatively moving joints.
Static seal usually refers to the seal between two stationary faces. There are three main types of static seals: gasket seals, sealant seals, and direct contact seals.
Dynamic seal refers to the seal between the relative moving parts in the machine (or equipment).
Packing seals are mainly used for dynamic seals of the moving parts of process machinery and equipment in the mechanical industry, such as centrifugal pumps, compressors, vacuum pumps, mixers, shaft seals of reaction kettles and reciprocating pumps, plungers or piston rods of reciprocating compressors And the seal between the linear and spiral motion valve stem and the fixed body.
Under low pressure, the sealing effect is good. The use temperature is limited, such as nitrile rubber can only be used at 60 ℃.
The oil seal is the seal of the lubricant. It isolates the parts in the transmission parts that need to be lubricated from the output parts, so that the lubricant does not leak.
Oil seals are required wherever there is liquid lubricating oil in the moving body box and it is connected to the outside. Some are rubber, some are metal, and most are steel-bone rubber, such as rear crankshaft oil seals, transmission front and rear oil seals, left and right half shaft oil seals, front reducer oil seals, air compressor crank oil seals, and so on.
Sealing gasket is a kind of sealing spare parts used in machinery, equipment and pipelines wherever there is fluid. It uses internal and external materials for sealing.