US 6,007,105 AGranted

Swivel seal assembly

AssigneeKalsi Engineering, Inc.

InventorsLannie Dietle, Manmohan S. Kalsi

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Abstract

A swivel seal assembly is defined for providing sealed high pressure fluid communication between relatively rotatable generally coaxial conduits where dynamic runout and static misalignment may occur to one conduit relative to the other. A generally tubular washpipe is mounted in pivotally articulating relation to one conduit, and a generally tubular seal housing is telescoped over the washpipe and mounted in pivotally articulating relation to the other conduit. High pressure, staged rotary seals are supported by the seal housing and maintain bearing and sealing engagement with the washpipe so that the seal housing and washpipe articulate in unison in response to said static misalignment and dynamic runout, thereby virtually eliminating relative lateral motion between the seal housing and washpipe and minimizing rotary seal extrusion damage. The seal housing and washpipe are hydraulic force balanced regardless of the pressure to which they are subjected, and thus are not subject to pressure induced loads which might otherwise interfere with articulation.

Claims30

Dependent claims

A pressure balanced rotary seal assembly for conducting a fluid having a fluid pressure between the first and second conduits of a swivel apparatus having a frame supporting the first and second conduits in relatively rotatable axially spaced relation, comprising:

(a) a washpipe of elongate, generally tubular form, having a first washpipe end for facing the first conduit and a second washpipe end for facing the second conduit, said washpipe defining an external generally cylindrical sealing surface;
(b) a seal housing of generally tubular form having a first housing end having a housing flexible seal for establishing a housing flexible sealing interface with the first conduit and thereby defining a first seal housing pressure responsive area and having a second housing end for facing the second conduit and being disposed about said first washpipe end, said seal housing supporting at least one rotary seal in rotatable sealing engagement with said external generally cylindrical sealing surface and defining a second seal housing pressure responsive area substantially equal and opposed to said first seal housing pressure responsive area such that opposed pressure induced hydraulic forces acting axially and oppositely on said seal housing are substantially balanced and thus said seal housing being readily pivotally articulatable about said housing flexible sealing interface and also defining a first washpipe pressure responsive area substantially equal to said first and second seal housing pressure responsive areas;
and
(c) a washpipe flexible seal for sealing engagement with said washpipe and the second conduit and for establishing a washpipe flexible sealing interface therewith and thereby defining a second washpipe pressure responsive area being substantially equal and opposed to said first washpipe pressure responsive area, such that opposed pressure induced hydraulic forces acting axially and oppositely on said washpipe are substantially balanced and said washpipe thus being readily pivotally articulatable about said washpipe flexible sealing interface in unison with said seal housing at all conditions of fluid pressure.

1 more element

A rotary seal assembly for conducting a fluid having a fluid pressure between the first and second conduits of a swivel apparatus having a frame supporting the first and second conduits in relatively rotatable axially spaced relation, comprising:

(a) a washpipe of generally tubular form having a first washpipe end for facing the first conduit, and a second washpipe end for facing the second conduit, and having an external generally cylindrical sealing surface;
(b) a seal housing of generally tubular form having a first housing end for facing the first conduit and having a housing flexible seal for establishing a housing flexible sealing interface with the first conduit and said seal housing and thereby defining a first seal housing pressure responsive area, and having a second housing end for facing the second conduit and telescoping over said first washpipe end, a plurality of rotary seals positioned within said seal housing in rotatable sealing engagement with said external generally cylindrical sealing surface, said plurality of rotary seals defining a second seal housing pressure responsive area substantially equal and opposed to said first seal housing pressure responsive area such that opposed pressure induced hydraulic forces acting axially and oppositely on said seal housing are substantially balanced such that said seal housing being substantially free of axially acting hydraulic loads and thus being readily pivotally articulatable about said housing flexible sealing interface at all conditions of fluid pressure, said plurality of rotary seals defining a first washpipe pressure responsive area substantially equal to said first and second seal housing pressure responsive area;
(c) a washpipe flexible seal for sealing engagement with said washpipe and the second conduit and for establishing a washpipe flexible sealing interface with the second conduit and thereby defining a second washpipe pressure responsive area being substantially equal and opposed to said first washpipe pressure responsive area, such that opposed pressure induced hydraulic forces acting axially and oppositely on said washpipe being substantially balanced such that the washpipe being substantially free of axially acting hydraulic loads and thus being readily pivotally articulatable about said washpipe flexible sealing interface in unison with said seal housing at all fluid pressure conditions;
(d) pressure dividing means dividing the fluid pressure among said plurality of rotary seals;
and
(e) bearing means establishing guiding engagement between said seal housing and said washpipe and positioning said second end of said seal housing in substantially concentric orientation with said first end of said washpipe.

3 more elements

(a) a washpipe of elongate, generally tubular form having a first washpipe end for facing the first conduit and a second washpipe end for facing the second conduit, said washpipe defining an external generally cylindrical sealing surface;
(b) a seal housing of generally tubular form having a first housing end for facing the first conduit and having a housing seal for establishing a sealing interface with the first conduit and said seal housing, and having a second housing end for facing the second conduit and telescoping over said first washpipe end;
(c) a plurality of rotary seals located within said seal housing and having rotatable sealing engagement with said external generally cylindrical sealing surface and defining a first washpipe pressure responsive area;
(d) a washpipe flexible seal for sealing engagement with said washpipe and the second conduit and for establishing a washpipe flexible sealing interface with the second conduit and thereby defining a second washpipe pressure responsive area being substantially equal and opposed to said first washpipe pressure responsive area, such that opposed pressure induced hydraulic forces acting axially and oppositely on said washpipe being substantially balanced and said washpipe being substantially free of axially acting hydraulic loads and thus being readily pivotally articulatable about said washpipe flexible sealing interface at all conditions of fluid pressure;
(e) pressure dividing means dividing the fluid pressure among said plurality of rotary seals.

2 more elements

Dependencies are inferred from the claim text.