VX SS316 600LB High Pressure O Rings

R type combination ring gaskets have different designations on each side.Combination ring gaskets allow the connection of flanges, with the same bolt circle measurement and number of bolt holes, that have different designated gaskets. 

There is no dimensional difference between the standard RX and SRX or the BX and SBX. They will fit into their appropriate flange designated numbers. The "S" prefix identifies a gasket as having intersecting vent holes, allowing a pressure less metal-to-metal initial contact between the gasket and flange groove, while made up underwater. For pressure class ratings on these gaskets refer back to their non "S" type standard gasket classification chart for the RX-Series and BX-Series. Gaskets that have been torqued initiating a metal-to-metal seal should be discarded and not reused.

SBX Gasket API specified optional drilling patterns for vent holes. SBX gaskets have a bleed hole on their I.D. joining to their equalizing hole, to assure that any liquid trapped behind the ring gasket on either side will vent (flow) to the I.D. bore of the assembly as the connection comes together. This allows the connection to close as designed and the ring gasket to coin and form a permanent seal.

SRX gaskets are not specified in any national or international standards, but they can be modified to have the same vent hole arrangement.