Back-up-rings

Back-up rings

Back-up rings, often referred to as back-up rings, are used in combination with O-rings to avoid gap extrusion. With high pressure and large gap extrusion, there is a risk that the material of the O-ring will be squeezed into the sealing chamber on the side where there is no pressure. If this process is repeated and the pressure increases further, the O-ring is damaged and this is detrimental to the function and service life of the O-ring. The O-ring may be damaged beyond repair and finally break down completely. To reduce the risk, support rings are used. Support rings have no sealing function. By reducing the sealing gap, support rings ensure that the O-ring can take over its sealing function more permanently and without damage. The operating parameters are determined by the selected O-ring, the pressure resistance of the sealing system is determined by the support ring.
The standard NBR support ring is an endless ring with a concave cross-section. For these support rings, sealsupply uses the compound NBR 90° Shore to ensure high dimensional stability and wear resistance. These reduce the sealing gap on the non-pressure side of the O-ring. In many cases, support rings are used in hydraulics, for example in hydraulic valves and hydraulic pumps. Support rings are also used in combination with O-rings in sealing cylinder bottoms and heads. Support rings are also applied in various other areas.

Mounting

Damage to the back-up ring should be avoided during assembly, as this will impair its function.

Types