R-Type, RX-Type, & BX-Type Ring Joint Gaskets

The basic idea of ring type joints is the same regardless of the application: A ring gasket locks into a groove and makes a seal. The gasket typically deforms under the pressure of bolting down the grooved flange, forming a tight, all-metal seal.

RTJs come in different metals, from soft iron to stainless alloys. There are also different designs:

• R-type ring joint gaskets: R RTJs are available in oval and octagonal cross-section designs. These fit standard flanges, as opposed to BX RTJs.
• RX-type ring joint gaskets: RX RTJs are wider than R RTJs. This separates the flange faces at maximum torque and seal, which, in turn, makes the joint more resistant to shock loading and vibration. RX RTJs fit standard flanges.
• BX-type ring joint gaskets: BX RTJs fit American Petroleum Institute flanges. They compress in a two-stage process that seals the outside and inside angles in succession. They also have a vent hole for pressure equalization and a reliable, even seal.

A final note on ring gaskets: It is typically not a good idea to reuse gaskets. While most gaskets are ideally single-use parts anyway, re-using a ring gasket comes with the added risk of potentially deforming grooves and therefore necessitating the replacement of entire ring type joints — flange and all.