公开(公告)号：US3915227A

公开(公告)日：1975-10-28

申请号：US51770874

申请日：1974-10-24

Applicant: DRESSER IND

Inventor： SIMPSON HARRY ELWOOD

IPC: E21B21/00 ,  E21B33/02 ,  E21B33/124 ,  E21B33/127

CPC classification number: E21B33/02 ,  E21B21/00 ,  E21B33/1243 ,  E21B33/127

Abstract: Apparatus is disclosed for borehole drilling which provides a pressure-tight seal between the drill pipe and the borehole or casing. The apparatus uses resilient elements between the borehole and the body portion of the drilling head. The resilient elements may be engaged in sealing engagement in the borehole by hydraulic or air inflation.