Elliptical pad is a type of gasket for metal ring pads, in addition to octagonal pads.
The octagonal gasket achieves sealing through surface contact. Although the sealing effect is slightly inferior to that of the elliptical gasket, it can be reused. However, the elliptical gasket cannot be reused. Its connection with the flange shows linear contact and good adhesion, but it needs to be tightened twice. For this, the octagonal gasket only needs to be tightened once.
Therefore, both types of gaskets have their own advantages and disadvantages.