A Square Ring is a sealing device made in the form of a torus (round top view), with a square-shaped cross-section (side view).
Other names for Square Rings are Washer Rings, Lathe-Cut Rings.
The primary reason for using a Square Ring in a sealing application is that they provide more sealing surface area – and at a cost that is comparable to other sealing device. For existing applications, there is no need to change the design or procedures. Square Rings fit in o-ring grooves and are interchangeable size-for-size.
Square Rings are available in a variety of rubber and plastic materials such as NBR, Viton, EPDM, Teflon, etc. In most static applications, a Square Ring will serve as a direct replacement for an o-ring and generally will perform a high-pressure sealing function as well as or better than an o-ring.
Features of Square Rings: