Since rubber is an elastic material,it will deform under load,especially under high pressure,it will make the sealing ring squeeze into the sealing gap,affect the floatability and make the sealing failure.

Therefore,the hardness and cross-sectional diameter of the o-shaped rubber sealing ring should be reasonably selected according to the use pressure.Generally,the sealing ring with higher hardness is selected at high pressure,and the sealing ring with lower hardness is selected at low pressure.The hardness of the commonly used rubber o-type rubber sealing ring is 70 plusmn;5.

The mold parting surface of the O-ring seal used in the manufacture of mechanical seals should avoid the inner,outer and upper and lower working surfaces as much as possible.Generally,45deg;mold opening is used to ensure good sealing performance.The cross-sectional size should be uniform,and the cross-sectional shape should refer to the figure below.The surface of the o-shaped rubber sealing ring must be smooth and flat,and there must be no defects such as unevenness,bubbles,and impurities.