Profiles , , and are "convex" grooved
gaskets. Compared with standard design they have
better sealing behavior.
The crests have - as all other profiles - the same parallel
plane. Bottoms of the grooves however follow a convex
root form. Soft sealing covering layers of plastically moldable
material form a thick padding in the middle of the profile.
The higher specific contact pressure in the middle causes
localized extraordinary good flow of the sealing covering
layers into the flange surfaces unevenness and roughness.
The soft sealing layer thickness is 0.5mm for graphite,
A.F.S. *, aluminum and silver and 0,35mm for PTFE.
The "convex" Grooved gaskets to profile B27A, B29A,
B25A and E27A minimizes edge pressure due to flange
rotation.
Standard gaskets lift at the inner diameter under flange rotation
conditions (about 1 degree max.) because the main
force of the flanges is located more towards the outer side
of the gasket diameter. With the newly developed profiles
B27A, B29A, B25A and E27A the contact diameter b is
preserved. These gaskets are particularly suited for flange
connections under cycling pressures and temperatures