What is BS 5106 – spiral anti-extrusion back-up rings about?
The efficient use of “O”-rings depends upon the ability of the elastomeric “O”-ring to resist extrusion through the working clearances between mating parts. Back-up rings provide added resistance support to a seal and minimise the risk of extruding a the seal in its housing when under pressure.
BS 5106 is a British Standard that specifies the design and dimensions of a range of spiral anti-extrusion back-up rings that prevent “O”-rings, which are manufactured in accordance with BS 4518, from extruding under pressure or where extrusion clearances are in excess of those specified in BS 4518. These spiral back-up rings are particularly suitable for use in hydraulic diametral sealing applications where the pressures exceed 100 bar1) and are generally less than 200 bar.
Who is BS 5106 - spiral anti-extrusion back-up rings for?
BS 5106 on ‘spiral anti-extrusion back-up rings’ is useful for:
- The manufacturing sector
- The plastics / rubber industry
- Manufacturers and suppliers of anti-extrusion and back-up rings
- Manufacturers of products where anti-extrusion back-up rings are used
- Product design engineers / innovation teams
- Quality control / testing personnel
- Compliance / audit teams
Why should you use BS 5106 - spiral anti-extrusion back-up rings?
Under certain circumstances, it is necessary to increase the resistance to extrusion by the use of back-up rings. BS 5106 specifies requirements for a range of spiral back-up rings that are compatible with “O”-rings manufactured in accordance with BS 4518.
The width and radial depth of the grooves specified here are such that the spiral back-up rings, by virtue of their coiling action, may be fitted in assemblies in which the internal or external diameter is a rounded metric dimension.
BS 5106 guidelines help you to follow best practices when manufacturing spiral anti-extrusion back-up rings so that they can support the actual sealing elements of a design and stop them extruding under higher pressures, or where metalwork clearances are larger than is ideal.
