Ring type Joint Gaskets are designed to seal by "initial line contact" or wedging action between the mating flange and the gasket. By applying pressure on the seal interface through bolt force, the softer metal of the gasket flows into the imperfections of the harder flange material, creating a very tight and efficient seal.
They are mainly used in the oil field on drilling equipment. Ring type joints are also commonly used on pipework & valve assemblies, along with some high integrity pressure vessel joints.
Ring joint gasket can be manufactured in accordance with all relevant gasket standards and specifications to suit the following flange designations
|API605 (ASME B16.47 SERIES B)|
|FRENCH: NF STANDARD|
|MSS SP44 (ASME B16.47 SERIES A)|
Style R Oval and Octagonal configurations are interchangeable on flat bottomed groove flanges. Oval section being a modified version providing better sealing performance.
Oval - The contact face is in oval shape. It provides a high reliabililty seal. Fits the round and flat bottom ring groove flange. These gaskets are manufactured in accordance to API 6A of ASME B16.20 to suit API613 and ASME/ANSI B16.5 Flanges.
Octagonal - Dimensionally more accurate and with a better surface finish than the oval style because it consists of straight surfaces only. Fits only the modern flat bottom groove flange. A higher torque load is required to flow the gasket material into imperfections of the flange facings. These gaskets comply with API6A of ASME B-16.20. to suit API 6B and ASME/ANSI B16.5 Flanges
The RX type RTJ gasket is manufactured in accordance to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges. The RX is a pressure energized version of the R octagonal gasket and fits the R type flat bottomed groove. The RX has an increased height and utilizes the internal system pressure to energize and improve the seal as internal pressure increases. Some RX sizes have a pressure relief hole to equalize pressure on both sides of the sealing faces.
The ‘RX’ style Octagonal RTJ is interchangeable with style ‘R’ Oval and Octagonal RTJ’s with the same ring size designation number and can be inserted into standard flanges with flat bottomed ring grooves. As the ‘RX’ style RTJ’s are much taller than standard style ‘R’ RTJ’s, the stand-off distance between the mating flanges will be greater.
Style BX - used for very high pressures up to 20,000 psi. A pressure balance hole equalises any pressure which may be trapped in the grooves.
Typical high pressure and temperature applications where these gaskets are used include valve and pipe-work assemblies in oil field drilling and refining applications.
When correctly fitted, the style BX gasket allows virtual face to face contact of the flange faces.