The selection of the compression rate W of the rubber O-ring should consider the conditions of use, static seal or dynamic seal; static seal can be divided into a radial seal and axial seal; the leakage gap of a radial seal is a radial gap, and the leakage of axial seal The gap is the axial gap. According to the pressure medium acting on the inner diameter or outer diameter of the O-ring, the axial seal can be divided into internal pressure and external pressure. The internal pressure increases and the external pressure decreases the initial tension of the O-ring.

Rubber Rings Manufacturer introduces that because of different forms of static seals, the direction of action of the sealing medium on the O-ring is different, so the pre-pressure design is also different. For dynamic seals, it is necessary to distinguish between reciprocating motion seals and rotary motion seals.

1. Static sealing: the cylindrical static sealing device is the same as the reciprocating sealing device, generally W=10%～15%; the plane static sealing device is W=15%～30%.

2. For dynamic sealing, it can be divided into three situations; reciprocating motion generally takes W=10%～15%. Rotary motion seals must consider the Joule heating effect when selecting the compression ratio. Generally speaking, the inner diameter of the O-ring for rotary motion is 3%-5% larger than the shaft diameter, and the compression rate of the outer diameter W=3%-8%. O-rings used for low-friction movement generally choose a smaller compression rate, that is, W=5%-8%, to reduce frictional resistance. Also, the expansion of the rubber material caused by the medium and temperature must be considered. Usually, outside the given compression deformation, the maximum allowable expansion rate is 15%. Exceeding this range indicates that the material selection is inappropriate, and O-rings of other materials should be used, or the given compression deformation rate should be corrected.