Sealing apparatus having sequentially engageable seals

In combination:

• a) a mechanical unit including a movable shaft mounted at least in part within a stationary housing;
• b) a seal assembly mounted within said stationary housing for sealing said shaft, said seal assembly comprising:
• i) a plurality of resilient seal members mounted with respect to said stationary housing, at least one of said resilient seal members disposed to assume a preloaded condition out of contact with said shaft and a loaded condition in sealing contact with said shaft;
• ii) a barrier member defining a barrier region in axial alignment with said shaft, said barrier region being between said shaft and said at least one resilient seal member in its preloaded condition, said barrier member physically interposed between said shaft and said at least one resilient seal member in its preloaded condition, said barrier member mounted for movement relative to said shaft;
• wherein said at least one resilient seal member deploys from said preloaded condition to said loaded condition in response to movement of said barrier member relative to said shaft, and wherein said movement effects sealing engagement between said at least one resilient seal member and said shaft.

A method for supporting a shaft within a sealing apparatus having a plurality of resilient seal members, comprising:

• providing a sealing apparatus having a housing defining a shaft opening and a plurality of resilient seal members within the housing and coaxial with the shaft opening;
• inserting within the shaft opening of the housing a barrier member in axial alignment with said resilient seal members, such that said barrier member is received within at least one of the resilient seal members;
• providing a front bushing within the housing at a front end of the shaft opening;
• providing a rear bushing within an annular recess formed in the barrier member;
• providing a shaft within the housing and within the barrier member, said barrier member being axially movable relative to said shaft, said barrier member physically interposed between said shaft and the at least one of said plurality of resilient seal members, said shaft being supported by the front and rear bushings and being maintained in axial alignment with the resilient seal members by the front and rear bushings.