(19)

(11)

EP 2 337 918 A1

(12)

(43) Date of publication: 29.06.2011 Bulletin 2011/26 (21) Application number: 09820305.2 (22) Date of filing: 03.09.2009

(51) International Patent Classification (IPC):  E21B 4/14(2006.01) E21B 7/20(2006.01) E21B 21/00(2006.01) (86) International application number: PCT/FI2009/050700 (87) International publication number: WO 2010/043757 (22.04.2010 Gazette 2010/16)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR Designated Extension States: AL BA RS (30) Priority: 13.10.2008 FI 20085961 (71) Applicant: Oy Atlas Copco Rotex Ab 33330 Tampere (FI)	(72) Inventor: AHONEN, Jukka 33530 Tampere (FI) (74) Representative: Kangasmäki, Reijo Holger  Finnish Patent Consulting FPC Patenttikonsultointi Kangasmäki Oy PL 25 FIN-33401 Tampere FIN-33401 Tampere (FI)