US Patent 10415321 Washpipe seal assembly

A washpipe assembly includes a seal stack including at least one packing ring adapted to seal between a washpipe and the seal housing; a packing spacer ring adapted to maintain spacing between the seal housing and the washpipe, and a guide bushing ring positioned between the packing spacer ring and the washpipe. The guide bushing ring is made from a softer material than the wash pipe such that any contact therebetween will avoid damage to the washpipe. Additionally, the inclusion of the guide bushing ring may allow the packing spacer ring to be offset further from the washpipe than otherwise allowable.