Traditional flanges such as ANSI, DIN and BS all rely on a dynamic joint which, when bending forces and tensile loads are applied, become loose and weak. The gap created by the raised face introduces corrosion problems particularly to the bolting aspect, which is a particular issue in critical environments as the design actually depends on the large bolt forces to maintain gasket integrity.

As flange size and pressure requirement increase the bolting requirement becomes increasingly heavy and complex resulting in high procurement, installation and maintenance costs. Large flange diameters in particular are difficult to work with, and inevitably require more space and have a more challenging handling and installation procedure, particularly on remote installations such as oil rigs.

The principle design of the flange face includes two independent seals. The first seal is created by application of seal seating stress at the flange heel.

Heel contact will be maintained for pressure values up to 1,8 times the flange rating at room temperature.

The flange also remains in contact along its outer circumference at the flange faces for all allowable load levels.

The main seal is the IX seal ring. The seal ring force is provided by the elastic stored energy in the stressed seal ring. Any heel leakage will give internal pressure acting on the seal ring inside intensifying the sealing action.

The design aims at preventing exposure to oxygen and other corrosive agents. Thus, this prevents corrosion of the flange faces, the stressed length of the bolts and the seal ring.