What are the external factors that affect the seal? Most of the factors influencing the seals by external action summarized here are derived from testing. These factors include seal clearance, manufacturing accuracy (centre, centering, roundness, etc.), surface characteristics, reciprocating distance, and frequency. They are related to the specific characteristics of the pressure medium and the characteristic parameters of the device, such as pressure, speed, working time, parking time and temperature.

1. There are three significant deviations between the surface of the machined component and the ideal profile: shape deviation, wave deviation and roughness deviation. The three appear in different combinations, and the use of elastic material seals close to the surface can compensate for the deviation of the shape of the first two cases. The increase in wear caused by the third roughness deviation is unavoidable. The allowable roughness (wind or ruler) of the metal surface to which the seal is fitted has a strict specification: the static surface seal allows the ruler R to be between 0.5 and 1.5 ;; the sliding face seal. The value cannot exceed 0.25m.

2. Sealing gap The sealing gap of the static surface seal can be reduced to the size of the sliding fit. The sealing gap of the sliding surface seal is also the sliding gap. Therefore, the sealing gap should be determined according to different requirements, so that it meets various industrial standards. The relative position of the gap and the seal should be adjusted, otherwise the bottom of the seal is easily squeezed into the seal gap. The solution is to use a protective retaining ring to prevent the seal from being pressed into the gap.