About Ring Type Joint Gaskets
Ring Type Joint gaskets are metallic sealing rings, suitable for high-temperature and high-pressure applications. They're always applied to special, accompanying flanges which ensure good, reliable sealing with the proper selection of materials and profiles.
RTJ gaskets are created to seal by "initial line contact" or wedging action between the coupling flange and the gasket. The pressure is applied on the seal interface through bolt force, the "softer" metal of the gasket flows into the microfine structure of the harder flange materials, making a very tight and efficient seal.
Style R, RX and BX Ring Types
The Style R ring is the most applied type that is manufactured in accordance with ASME B16.20 used with ASME B16.5 flanges, class 150 to class 2500. Style 'R' ring type joints are designed and manufactured in both octagonal and oval configurations.
The Oval has a lower sealing efficiency than the octagonal ring and would be the preferred gasket. Only the oval cross-section may be utilized in the old type round bottom groove. The newer flat bottom groove design can accept either the oval or the octagonal cross-section.
Style R ring type joints are created to seal pressure up to 6,250 psi in accordance with ASME B16.5 pressure ratings and up to 5,000 psi.
The RX type is more suitable for pressures up to 700 bar. This RTJ is capable of sealing itself. The outermost sealing surfaces make the first contact with the flanges. Higher system pressure causes higher surface pressure. RX Type is interchangeable with the standard R-models.
The BX type is more suitable for very high pressures up to 1500 bar. This BX type ring joint is not interchangeable with other types and is only best suited for API BX type flanges and grooves.
The sealing surfaces on the ring joint grooves must be smoothly finished to sixty-three Microinches and can be free of objectionable ridges, chatter marks, or tools. They seal by an "initial line contact" or a wedging action as the compressive forces are applied. The hardness of the ring is less than the hardness of the flanges.
