US 5,246,295 AGranted

Non-contacting mechanical face seal of the gap-type

OwnerRussell D. Ideinventor

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Abstract

A rotary mechanical face seal for preventing leakage of a fluid, either liquid or gas, across two relatively rotating surfaces. The seal is of the non-contacting mechanical type in which a predetermined spacing is maintained between the relatively rotatable sealing washers by formation of a pressurized fluid film between the relatively rotating surfaces. The opposed faces are constructed to provide a separation of the faces at start-up and thereby prevent damage or destruction to the faces before design pressures are achieved. This is achieved by providing at least one of the opposed faces with a deflection bearing portion which causes the necessary deflections under load. The bearing portion comprises a spaced series of lift pad sections. A variety of lift pad constructions can be used. The seal also includes a hydrodynamic radial bearing which centers the shaft in the static state to avoid shaft runout.

Claims21

Dependent claims

A gap-type rotary mechanical seal assembly comprising:

a housing;
a shaft;
relatively rotatable sealing members having substantially radially disposed confronting sealing faces, one of the sealing members being secured to the shaft for rotation therewith, the other sealing member being supported in the housing, one of the sealing members being axially movable relative to the other member;
a hydrodynamic bearing for supporting the shaft in the housing, the hydrodynamic bearing comprising a plurality of spaced bearing pads, each bearing pad being supported by a support structure, at least one of the bearing pads being supported such that under static load the bearing pad deflects such that the trailing edge contacts the shaft so as to maintain the shaft in a centered position;
at least one of the sealing members comprising a ring having a bearing portion and a sealing portion, the bearing portion including a plurality of spaced pad sections, each pad section having a shape and support structure such that under load the sealing surface of the pad deflects to form a hydrodynamic wedge;
and at least one of the sealing members being supported on a support structure for movement with six degrees of freedom.

3 more elements

Dependencies are inferred from the claim text.