(19)

(11)

EP 0 910 708 A1

(12)

(43) Date of publication: 28.04.1999 Bulletin 1999/17 (21) Application number: 97928205.0 (22) Date of filing: 12.06.1997

(51) International Patent Classification (IPC):  E02B 17/ 02( . ) (86) International application number: PCT/EP1997/003110 (87) International publication number: WO 1997/048858 (24.12.1997 Gazette 1998/03)

(84) Designated Contracting States: DK GB NL (30) Priority: 17.06.1996 EP 19960201687 (71) Applicant: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V. 2596 HR Den Haag (NL)	(72) Inventor: VAN DE GRAAF, Jan, Willem NL-2596 The Hague (NL)