Explain the seal of the sealing principle

Explain the seal of the sealing principle. That the seal (rotating dynamic seal) sealing machine, and sealing principle reason lubrication characteristics of two parts. Lubrication: oil seal friction characteristics are affected by the viscosity of the fluid and the sliding speed control, the relative sliding of the shaft seal surfaces separated lubrication oil film of moving, so keeping friction, wear small. Sealing principle: the sliding contact surface of the seal oil flow from the atmosphere side  Hydraulic ferrules  oil side and from the oil side to the atmosphere side of the loop. The sliding surface lubrication, prevent wear and tear, thus there is no leakage. When moving speed is too high, the impact of a continuous lubricating film formation, resulting in frictional heat increases the temperature range beyond the seal material is caused by damage to the seal. Pressure is too large, in addition to affecting film formation, but also on the rubber seals have a "squeeze gap" effect, generally can be added, "ring" to improve. Or select a low coefficient of friction, good self-lubricating PTFE seals portfolio structure will help to improve the lubrication between the friction, suitable for high speed and high pressure systems reciprocating cylinder piston, the piston rod seal. Depending on the system environment, working conditions and a reasonable selection of media seals and sealing materials, proper installation and maintenance of seals, is to obtain effective sealing effect, reliability and service life of the key.