Custom Silicone Rubber Lip Seal
Rubber lip seal can be called as Rubber plunger seal, Rubber O-ring,Rubber gasket. It is a self-sealing ring, it relies on the lip and close to the surface of the sealing coupling, obstructing the leakage channel to obtain the sealing effect. The working pressure of the lip seal is the sum of the pre-pressing force and the fluid pressure. When the pressure of the sealing medium is increased, the lip is distracted and more closely fit with the sealing surface, so that the sealing performance be enhanced further. In addition, the lip edge also has the scraping oil function which also enhance the sealing performance of the seal.
Silicone lip seals are mainly used in reciprocating seals, and compare with extrusion seals, such as O-ring, the reciprocating seal makes lip seals better overall performance, and longer service life.
Lip seal pressure changes with the media pressure changes,it always adapt to media pressure change when work,which can guarantee adequate sealing pressure, but not produce too much friction.
Extrusion seals, like O-ring,mainly produce sealing force by pre-compression force, the seal ring contact pressure
given in advance, it can not be changed according to the media pressure changes during work. If required to seal a
large pressure then the pre-pressure must also be great, while the large pre-pressure will increase the contact stress
and contact area of the seal ring and sealing surface, which results in a great frictional resistance. Too much friction will cause damage to the seal, difficulty in starting up at low pressures or creeping. The lip seal opening and deformation can compensate for the small amount of wear, so as to ensure the sealing effect and the sealing life. The O-ring directly affects the sealing performance as the friction margin decreases.
In addition,the o-ring are easy to cause rolling and twisting in reciprocating seal, however,the lip seal is not obvious.
Compare with O-ring,the main disadvantage of lip seals is that they can only be used as a one-way seal. Two seals are required if used as a two-way seal, which increases the seal length.The grooves are difficult to design, Moreover, oil trapped between the two seals will cause oil pressure and back-pressure damage. However, the cross-sectional shape of the pre-compression type seal ring is symmetrical and can be used as a bidirectional seal with small volume and easy groove design.
Based on the above comparison, with a small amount of leakage allowed,the extrusion seal can reduce the groove size, but when require high seal performance, it choose the comprehensive performance lip seal.
|Description||Y-shaped seal(Lip Seal)||O-ring seal(Extrusion Seal)|
Seal section size is small, the
installation groove can be designed
as a monolithic groove; groove
processing, seal installation easy,can be used as two-way seal (dual pressure)
Excellent seal performance;
Low friction at low pressure;
Automatically compensate after
small amount of wear.
Poor sealing performance;
Easy to roll and twist, causing damage
The lower friction margin,the poorer
Complex sealing structure,large size;
Cause oil pressure between two
|Main application|| |
Small size slide valve;
Piston and rod seals which allow a small amount leakage
Piston and rod seals which require
high seal performance.
The typical shapes of the lip seal are divided into Y-shaped seal, V-shaped seal, U-shaped seal, L-shaped seal, J-shaped seal and others lip seal.