(19)

(11)

EP 0 946 431 A1

(12)

(43) Date of publication: 06.10.1999 Bulletin 1999/40 (21) Application number: 97913956.0 (22) Date of filing: 29.10.1997

(51) International Patent Classification (IPC):  B01F 3/ 04( . ) B09C 1/ 08( . ) C02F 3/ 22( . ) B09C 1/ 00( . ) B09C 1/ 10( . ) E21B 43/ 00( . ) (86) International application number: PCT/US1997/019907 (87) International publication number: WO 1998/021152 (22.05.1998 Gazette 1998/20)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU NL PT SE (30) Priority: 15.11.1996 WO 1996US01846 25.11.1996 US 19960756273 26.08.1997 US 19970921763 (71) Applicant: K-V Associates Inc. Mashpee, MA 02649 (US)	(72) Inventor: KERFOOT, William, B. Falmouth, MA 02540 (US) (74) Representative: Charig, Raymond Julian  Eric Potter Clarkson, Park View House, 58 The Ropewalk Nottingham NG1 5DD Nottingham NG1 5DD (GB)