Back-Up Rings

In a sealing application, back up rings provide added extrusion resistance, and prevent damage to O rings and seals when subjected to high pressures, larger extrusion gaps, and/or high temperatures. One of the most common types of O ring failure is the extrusion failure. When the internal pressure of an application becomes too great, the O ring will actually extrude into the clearance gap. This extrudate will quickly be nibbled away causing a loss of material, and once sufficient material is lost, seal failure will quickly follow.

There are three options to prevent this, the first of which is to reduce the clearances to lower the extrusion gap. This is obviously an expensive option, so a cheaper solution is to raise the durometer of the O ring. Although, a higher durometer O ring offers superior extrusion resistance, is often not feasible solution due to material availablilty, and to the fact that harder durometer materials have limited low pressure sealability. The last and best option is the addition of a back up ring. Back up rings are installed to prevent the extrusion of an elastomeric O ring in its housing groove under certain operating conditions.

Back up rings are plastic or rubber rings used to prevent the O ring from entering the clearance gap. When high pressures are exerted on the O ring, its soft rubber material can be forced into the clearance gap causing the O ring to extrude. A back up ring is a ring of hard, extrusion resistant material such as high durometer nitrile, nylon, Hytrel, or PTFE. A back up ring is designed to fit between the O ring and the extrusion gap and prevent the extrusion of the O ring. While back up rings are used in conjunction with O rings in both static and dynamic sealing applications, the gland they fit in must be specially designed to fit both the O ring and the back up.

Owing to its unique features, these rings are widely used in a lot of industries and applications such as machine tools, automobile, metallurgical machinery, chemical machinery, engineering machinery, building machinery, plastics, agriculture and different instruments. These rings are successfully used in industries like hydraulics, pneumatics, food processing, pharmaceutical, construction, drilling, mining, injection moulding, steel production, military and defence, tyre production, oil field exploration, packaging, power generation, dairy, valves and cylinder repair industries and also in industries that require high chemical resistance, heavy duty or low friction applications.

Darcoid Nor Cal Seal is into supplying world class Electro Magnetic Inferance shielding Gaskets and Seals, O Rings, Molded Rubber Parts like rubber custom molded seals, EMI, RFI Shielding products like Adhesives, Sealants, Conductive Compounds, Conductive Elastomer Gaskets, Conductive Tapes and laminates, Conductive Grounding Tabs, Metal EMI products, O-Rings and D-Rings, Shielded Windows, back up rings, Shielded EMI Vents, Thermal Grease and Gap fillers, Wave Guides, Wire Mesh Gaskets and many more.

The endeavor has a remarkable reputation to be providing highest quality components that offer considerable reliability. With Darcoid Nor Cal Seal, which has experience in various areas of expertise, you can rest assured that your own rubber components will be manufactured to meet up to exact specifications. Darcoid's vast experience in managing seal supply chains uniquely qualifies the company as the choice for all your sealing needs. The company's value added programs are designed to integrate into your processes based on your company goals and supplier’s requirements. Darcoid Nor Cal Seal is the world’s leading diversified manufacturer of motion and control technologies and systems, providing precision engineered solutions for a wide variety of commercial, mobile, industrial, agriculture and aerospace markets.

At Darcoid Nor-Cal Seal, we take the time to learn about your unique needs, and then use our experience and knowledge to deliver you the best solution