(19)

(11)

EP 0 879 092 A1

(12)

(43) Date of publication: 25.11.1998 Bulletin 1998/48 (21) Application number: 97902488.0 (22) Date of filing: 06.02.1997

(51) International Patent Classification (IPC):  B01D 17/ 02( . ) B04C 9/ 00( . ) B04C 5/ 081( . ) (86) International application number: PCT/GB1997/000335 (87) International publication number: WO 1997/028903 (14.08.1997 Gazette 1997/35)

(84) Designated Contracting States: DE DK FR GB NL (30) Priority: 09.02.1996 GB 19960002631 (71) Applicant: Baker Hughes Limited London WC2H 9EH (GB)	(72) Inventors: LLOYD, David, Douglas North Avon GL9 1BX (GB) THOMPSON, Peter, Austin Gloucester GL2 0EN (GB) (74) Representative: Finck, Dieter, Dr.Ing., et al  Patentanwälte v. Füner, Ebbinghaus, Finck Mariahilfplatz 2 - 3 81541 München 81541 München (DE)