(19)

(11)

EP 2 013 478 A1

(12)

(43) Date of publication: 14.01.2009 Bulletin 2009/03 (21) Application number: 06820665.5 (22) Date of filing: 07.12.2006

(51) International Patent Classification (IPC):  F04B 17/04(2006.01) F04B 23/06(2006.01) (86) International application number: PCT/GB2006/050439 (87) International publication number: WO 2007/125270 (08.11.2007 Gazette 2007/45)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK RS (30) Priority: 29.04.2006 US 414163 (71) Applicant: National Oilwell Varco, L.P. Houston, Texas 77036 (US)	(72) Inventor: URQUHART, Richard Katy, Texas TX 77450 (US) (74) Representative: Lucas, Brian Ronald  Lucas & Co. 135 Westhall Road Warlingham Surrey CR6 9HJ Warlingham Surrey CR6 9HJ (GB)