Api ring gasket

R - Series Gasket
The R-Type ring gasket can be ordered in two different profiles, oval or octagonal in cross-sections. Both types have identical pitch diameter as the flange groove they correspond to. These gaskets are used in pressures up to 5, 000 PSI. The oval type is the only gasket that will fit a bottom radiused groove. Flanges with flat bottom v-grooves will accept either style.

RX - Series Gasket
RX gaskets are designed for pressures up to 5, 000 PSI. They are interchangeable with R-oval or R-octagonal rings used on API 6B flanges. RX type gaskets perform excellent in 6B flanged blowout preventer stacks, requiring the additional mass of the RX gasket to support the higher pressures with higher vibrations and heavier weights of these units.

BX - Series Gasket
The BX Series can only be used with 6BX flanges and 16BX hubs. BX Gaskets are designed for higher-pressure ratings starting at 5, 000 lbs. and ending with 20, 000 lbs. Pitch diameters on BX gaskets are slightly larger than the pitch diameter of the flange. This forces the gasket to initially seal on its outside angles and secondly seal with its inside angles as the flange is bolted down to respective torque settings.

Subsea Gasket
SRX and SBX series are American Petrolium standardized underwater rings. RX and SRX or the BX and SBX 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.