What is a backup o-ring?

Back-up Rings are flat, split, spiral or contoured washer type fittings used to protect an O-Ring seal from extrusion at higher pressures and temperatures. A Back-up Ring works by blocking or reducing the extrusion gap, thus preventing the o-ring from extruding.

What is the use of backup ring?

Backup Rings Overview In a sealing application, backup 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. Extrusion failure is one of the most common types of o-ring failure.

When should you use a backup ring?

When the pressure on an o-ring is increased to the point that it can no longer resist being extruded into the diametrical gap, and to compensate for loose fitting components, the use of backup rings to block the diametrical clearance gap and provide support for the o-ring may be a viable solution.

Why are backup rings sometimes used with O rings?

Back-up rings, or anti-extrusion rings, are thin rings that are designed to prevent O-ring extrusion under pressure. They fit in the gland between the seal and the clearance gaps to provide zero clearance.

What is an anti extrusion ring?

A Back-up Ring is an inflexible ring that holds an elastomeric seal to its outlined shape and in its right place. They are also called Anti Extrusion Rings and are typically used with O Rings to eliminate extrusion at high pressures.

What is a cure date and shelf life?

The Cure Date is the date that the rubber is fully molded in this process. Shelf(Storage) Life – the maximum period of time, from cure date, to the date an elastomeric product is used as a component part in assemblies, sub-assemblies, and systems.

What is the use of back up ring with seal in hydraulic system?

The primary purpose of the back up ring is to reduce the extrusion gap between metal surfaces of two cylinder components to enable the seal to operate at higher pressures without extruding and being damaged.

How long can you store O rings?

Learn About O-Ring Shelf Life and Storage Recommendations

Unlimited FKM, FFKM, Silicone, Fluorosilicone, EPDM, Butyl, FEPM
15 Years NBR Buna-N, HNBR, Chloroprene, Hypalon, ACM Polyacrylate
5 or 10 Years Polyurethane depending on type
3 Years SBR

Do unused O rings go bad?

And that is true, to a point. However, if an unused fitting has an O-ring, its shelf life is only as long as the life of the O-ring. The rubber industry uses older US military specifications and current SAE Aerospace recommendations to calculate O-ring shelf life in quarter year units.

Do unused O-rings go bad?

How long can you store O-rings?

Why do you need a backup O ring?

Backup O-rings ensure that the primary O-ring continues to provide the proper seal between opposing parts even under pressure. When first installed, O-rings are specked to fit perfectly, but when continually exposed to pressure and high temperatures, they lose material, weaken, and extrude beyond the groove in which they rest.

Can a PTFE backup ring be used on an O ring?

These PTFE backup rings resist harsh chemicals, such as acetone, fluorinated solvents, methanol, and many acids. Use them to extend the life of your O-rings and improve their performance in high-pressure applications. For technical drawings and 3-D models, click on a part number. Thick.

What do you call a back up ring?

A backup 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. Size not listed, special requirements or large quantities please click this link to Request a Price Quote.

What kind of rubber is a backup ring made of?

Made of Buna- N, these backup rings resist grease, petroleum fluids, and motor oil. Use them to extend the life of your O-rings and improve their performance in high-pressure applications.