(19)

(11)

EP 2 300 682 A1

(12)

(43) Date of publication: 30.03.2011 Bulletin 2011/13 (21) Application number: 09769412.9 (22) Date of filing: 10.06.2009

(51) International Patent Classification (IPC):  E21B 10/64(2006.01) E21B 7/20(2006.01) E21B 10/40(2006.01) (86) International application number: PCT/FI2009/050490 (87) International publication number: WO 2009/156569 (30.12.2009 Gazette 2009/53)

(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 TR Designated Extension States: AL BA RS (30) Priority: 26.06.2008 FI 20085643 (71) Applicant: Oy Atlas Copco Rotex Ab 33330 Tampere (FI)	(72) Inventors: VIRJULA, Antti FI-33250 Tampere (FI) GYLLING, Kai FI-33610 Tampere (FI) (74) Representative: Kangasmäki, Reijo Holger  Finnish Patent Consulting FPC Patenttikonsultointi Kangasmäki Oy PL 25 FIN-33401 Tampere FIN-33401 Tampere (FI)