Contoured elastomer rings are more commonly used now whereas previously PTFE had been the main material used. Depending on fittings either Solid, Split or Spiral PTFE rings can be used, along with the contoured alternatives. Back Up Rings which can also be classed as anti-extrusions rings are used in high pressure applications in conjunction with O Rings. Applications vary, so they must be checked individually, but as a guideline Back Up Rings can be used for dynamic applications over 100 bar, and for static applications up to about 950 bar.
PRODUCT DESCRIPTION BACK UP RINGS ADVANTAGES: O-Ring Life Time Increased When Using A Back Up Ring. Back Up Rings are Economic , Low Sealing Cost and Allows Larger Groove Machining Tolerances. Back Up Rings Have A Better Pressure Resistance Than O Rings. ( Recommended For Applications With Pressure Higher Than 50 Bars)