Patent ID: 6923254
Filing Date: 2005-08-02
Classification: E21B,F16L

Abstract:
1. A swivel sealing assembly comprising: a washpipe rigidly mounted to a rotating conduit; a packing box rigidly mounted to a stationary conduit and engaging said washpipe, wherein a circulating fluid flows through said washpipe and said packing box at an elevated pressure greater than ambient pressure; a plurality of seals contained within said packing box and adapted to seal against said washpipe and said packing box; a plurality of annular volumes defined by the sealing interfaces between said washpipe, said packing box, and two adjacent seals; a control system adapted to provide pressurized fluid to one or more of said plurality of annular volumes at a predetermined fraction of the elevated pressure of the circulating fluid; and a plurality of spacers within said packing box.