Why Are Style RX Joint Gaskets Not Used As Much As Style R?

First of all, Style RX is a pressure energized adaptation of the standard style or Gasket. The RX is designed to fit the same groove design as a standard style R, making the joints interchangeable. The modified design uses a pressure energized effect that improves the efficiency of the seal as the internal pressure of the system increases. 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.

RX Gaskets are similar in shape to the standard octagonal ring joint Gasket but their cross-section is designed to take advantage of the contained fluid pressure in affecting a seal. RX Gaskets are designed for pressures up to 15,000 PSI. The reason why they are not used as much is because they are more expensive than standard oval or octagonal rings, therefore making them not as popular.

Rx type Gaskets however, perform very well in 6B flanged blowout preventer stacks which requires the additional mass of the RX Gasket to support the higher pressures with higher vibrations and heavier weights of these units. The RX type RTJ Gasket is manufactured in accordance to API 6A and ASME B 16.20 to suite API 6B and ASME B 16.5 flanges.