There are elliptical sealing surface, octagon sealing surface is inclined, the two are different.

    The octagonal ring pad is matched with the flange groove, which is mainly manifested as surface contact. Compared with the oval ring pad, although it is difficult to achieve close with the flange groove, but it can be used again, and because the cross section is a straight line, easy to process.

    The oval ring pad is in line with the flange groove and has good sealing performance, but the machining accuracy is required to be high, thus increasing the manufacturing cost. At the same time, the oval ring pad cannot be reused.

    If the flanges are trapezoidal grooves, it is estimated that they can be interchanged. Commonly used r-type elliptical pads are divided into elliptic or octagon types according to the section. The standard r-type annular gaskets are manufactured according to the standard sizes of API 6A and ASME B16.20, and the maximum service pressure is 10000PSI. In trapezoidal groove flanges the octagon pads are interchangeable with the oval pads. The RX type is suitable for the standard R type ring gasket with pressure enhancement, and is suitable for the same R type flange groove sealing cover. The BX type is designed for pressure enhancement and applies up to 150 psi pressure systems.