(19)

(11)

EP 0 990 132 A1

(12)

(43) Date of publication: 05.04.2000 Bulletin 2000/14 (21) Application number: 98928926.9 (22) Date of filing: 05.06.1998

(51) International Patent Classification (IPC)7: G01N 15/00, G01M 3/06 (86) International application number: PCT/US9811/793 (87) International publication number: WO 9855/849 (10.12.1998 Gazette 1998/49)

(84) Designated Contracting States: AT BE DE DK ES FI FR GB GR IE IT NL SE (30) Priority: 06.06.1997 US 48799 (71) Applicant: TEXACO DEVELOPMENT CORPORATION White Plains,New York 10650 (US)	(72) Inventor: GREEN, Steven, R. El Dorado, KS 76047 (US) (74) Representative: Watkins, David et al Urquhart-Dykes & Lord,91 Wimpole Street London W1M 8AH London W1M 8AH (GB)