'O'-Rings

DESCRIPTION

An O-ring, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.
The O-ring may be used in static applications or in dynamic applications where there is relative motion between the parts and the O-ring. Dynamic examples include rotating pump shafts and hydraulic cylinder pistons.

How does an O-Ring seal?

Seals prevent fluids from escaping through the gaps in mating pieces of hardware. The O-Ring sits in the middle of a gland when it’s at rest, but as pressure begins to rise in the sealing system, the O-Ring shifts to the opposite side of the pressure. Because the material is soft, the O-Ring is mechanically squeezed to plug the hole between the two mating hardware pieces.

MORE INFO

O-rings are available in various metric and inch standard sizes. Sizes are specified by the inside diameter and the section diameter (thickness). In the US the most common standard inch sizes are per SAE AS568C specification (e.g. AS568-214). ISO 3601-1:2012 contains the most commonly used standard sizes, both inch and metric, worldwide. The UK also has standards sizes known as BS sizes, typically ranging from BS001 to BS932. Several other size specifications also exist.