(19)

(11)

EP 0 731 973 A1

(12)

(43) Date of publication: 18.09.1996 Bulletin 1996/38 (21) Application number: 95911550.0 (22) Date of filing: 01.12.1994

(51) International Patent Classification (IPC):  G21B 3/ 00( . ) (86) International application number: PCT/US1994/013824 (87) International publication number: WO 1995/016995 (22.06.1995 Gazette 1995/26)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 03.12.1993 US 19930160941 16.11.1994 US 19940340256 (71) Applicant: E-QUEST SCIENCES Mountain View, CA 94043 (US)	(72) Inventor: STRINGHAM, Roger, S. Woodside, CA 94062 (US) (74) Representative: Allard, Susan Joyce, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)