APPARATUS AND METHOD FOR RAISING AND LOWERING A PISTON IN A PISTON-CYLINDER ARRANGEMENT IN A DERRICK - Patent 0868593

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EP 0 868 593 A1

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(43)	Date of publication:
	07.10.1998 Bulletin 1998/41

(21)	Application number: 96943394.0

(22)	Date of filing: 18.12.1996

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International Patent Classification (IPC):

E21B 19/ 02^{( . )}
E21B 19/ 086^{( . )}

E21B 15/ 00^{( . )}

(86)	International application number:
	PCT/NO1996/000294

(87)	International publication number:
	WO 1997/023706 (03.07.1997 Gazette 1997/29)

(84)	Designated Contracting States:
	AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

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Priority:

22.12.1995 NO 19950005271

(71)	Applicant: MARITIME HYDRAULICS A.S.
	N-4639 Kristiansand (NO)

(72)	Inventor:
	VATNE, Per N-4639 Kristiansand (NO)

(74)	Representative: Hammar, Ernst, et al
	Albihns Patentbyra Stockholm AB P.O. Box 3137 103 62 Stockholm 103 62 Stockholm (SE)

(54)	APPARATUS AND METHOD FOR RAISING AND LOWERING A PISTON IN A PISTON-CYLINDER ARRANGEMENT IN A DERRICK