RTJ (Ring Joint Gaskets)
RTJ (Ring Joint Gaskets) are specially sized metallic gaskets manufactured to suit the precise dimensional requirements of a range of flanges. These high quality gaskets are precision engineered for high pressure applications and are available in a range of different styles and materials to suit different flange types, specifications and materials.
Oval and Octagonal Style RTJ (Ring Joint Gaskets)
Standard RTJs are available from AG in two basic shapes, an oval cross section and an octagonal cross section. These basic designs are utilised in applications with pressures up to 10,000 psi. The dimensions are standardised and require specially grooved flanges. The octagonal cross section has a higher sealing efficiency than the oval and would be the preferred form of gasket, all thing being equal. However, only the oval cross section style can be used in the old type round bottom groove flanges whilst the newer flat bottom groove flange design allows the use of either octagonal or oval RTJs.
The sealing surfaces of the ring joint grooves on the flanges must be smoothly finished to 63 microns and be free of objectionable ridges, tool or chatter marks to ensure a correct seal. Oval and Octagonal RTJs seal by an inline contact or an edging action as compressive forces are applied. To allow this to occur properly, the hardness of the RTJ should always be less than the hardness of the flange to prevent flange deformation. Dimensions for API RTJ gaskets and grooves are covered in ASME B16.20 and API 6A.
AG carries these high pressure gaskets in a wide variety of sizes for quick supply. Standard sizes range from R11 through to R105 (covers 15NB ANSI 300/600 Flanges through 900NB ANSI 900). These can all be provided in a range of different materials and can be delivered with PTFE coating if required. Non-standard size RTJs are also available from AG if required.
BX Style RTJs
BX RTJs are a more specialised RTJs designed for sealing in applications up to 15,000 psi. These high performance gaskets differ from oval or octagonal RTJs as they have a square cross section and tapers on each corner. They are only used on API 6BX flanges and are available in low carbon steel, 304 stainless steel and 316 stainless steel as standard.
RX Style RTJs
RX Ring Join Gaskets are somewhat similar in shape to standard octagonal RTJs but have a slightly modified cross section to allow them to take advantage of the contained fluid pressure when effecting a seal. RX RTJs are manufactured to API 6A and are interchanged with standard octagonal rings for oil field drilling and production applications utilising API 6B flanges.
RX RTJ gaskets are utilised in applications with pressures ranging up to 15,000 psi and are usually offered in low carbon steel, 304 stainless steel or 316 stainless steel.
Other Styles of RTJ
In addition to the styles described above, AG offers a number of other styles of Ring Joint Gaskets for specialised applications. These include our SRX and SBX RTJs which vented versions of RX and BX ring gaskets that are used in sub-sea wellhead installations, rubber coated rings, bridgeman gaskets, delta gaskets and lens gaskets. For more information on these, or to discuss the best selection for your application, please contact your local AG branch.
For more information on available sizes, styles or to discuss our extensive customisation and fabrication options, please contact your local AG branch.