The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 08, 2005
Filed:
Dec. 18, 2001
Peter Raymond Hughes, Stroud, GB;
Nigel Dennis Griffin, Nympsfield, GB;
Mark A. Colebrook, Cheltenham, GB;
Peter Raymond Hughes, Stroud, GB;
Nigel Dennis Griffin, Nympsfield, GB;
Mark A. Colebrook, Cheltenham, GB;
Schlumberger WCP Ltd., , GB;
Abstract
A rotary valve assembly for a rotary steerable tool is disclosed for directing flow of an abrasive laden drilling fluid; the valve assembly has a first sealing surface rotatably engaging a second sealing surface. At least one of the surfaces has at least about 5% of its area comprising interconnecting voids to an average depth of at least 0.02 mm. The interconnected voids allow fluid pressure to equalize between the sealing faces by flowing through the interconnecting voids to the sealing surfaces. Because the fit of the sealing surfaces of the valve is less than perfect, and because the voids on mating surfaces do not necessarily overlap, the 5% of the surface area comprising interconnected voids can easily translate to a 10% or more reduction in sealed area when both sealing surfaces have the interconnecting voids. The additional reduction in surface area subjected to differential pressure has substantially eliminated the hydraulic lock problem previously encountered upon startup.