Seal Faces 1

[YoYo2000]

Hi All, What is a convex and concave face?? Why are the seal faces lapped as convex or concave?? I dont have a particular application, but would like to know reason why. Thanks!!!

 

[flexibox]

Seal faces are normally lapped flat to within a few lightbands. This is measured under a monochromatic light using an optical glass. When sealing high pressures seal faces are often lapped convex to prevent OD contact due to pressure distortion. Convex lapping allows the seal face to form a fluid film. The same can be said for internally pressurised seals but opposite hence concave lapping but this is not common.
So convex is forming an angle from OD and concave from ID.

Trust this helps