A Modified Face Seal For Positive Film Stiffness

A modified face seal having a positive film stiffness is described and analyzed. The axial film stiffness is obtained by simply extending the seal nosepiece towards the shaft, thereby producing an annular clearance seal in series with the original face seal.

Conditions for maximum film stiffness and pressure balance operation of the modified seal are derived. A comparison is made between the modified and a conventional face seal and the new seal is found to be superior from a standpoint of overall performance.