Patent ID: 6896076
Filing Date: 2005-05-24
Classification: E21B

Abstract:
1. An apparatus for sealing around drill pipe while the drill pipe is rotating, comprising: an outer housing; an inner housing rotatably mounted in the outer housing about an axis of rotation; an annular bladder mounted in the inner housing; an annular resilient member mounted in the bladder; the inner housing having a passage for delivering hydraulic fluid pressure to an outer surface of the bladder to cause the bladder to deform inwardly, thereby forcing the resilient member to deform inwardly to grip and rotate with a drill pipe; the resilient member having a first end secured to the inner housing for rotating the inner housing as the drill pipe rotates and a second end that is free to move axially in response to the deformation against the drill pipe; and a shoulder in the inner housing, the shoulder being spaced from the second end of the resilient member by a gap while the resilient member is in an undeformed condition, the shoulder providing a stop to limit elongation of the resilient member while being deformed by the bladder.