Patent ID: 8608172

Claim:
A bulkhead seal comprising: a housing configured to be attached to a bulkhead about a shaft and defining an annular recess; an annular diaphragm seal rotatably disposed in the annular recess of the housing and about the shaft; a plurality of orifices through the annular diaphragm seal spaced circumferentially to prevent air pressure differentials from locking the annular diaphragm seal with respect to the housing; a lip seal on each axial side of the annular diaphragm seal including a seal portion disposed to seal and unseal the orifices; a retaining ring for each lip seal defining a pocket between each lip seal and its retaining ring; and a foam body in each pocket and including a gel material configured to expand the foam body in the presence of liquid urging the seal portions of the lip seals to seal the orifices, the gel material contracting the foam body when no liquid is present to unseal the orifices.