(19)

(11)

EP 0 658 268 A1

(12)

(43) Date of publication: 21.06.1995 Bulletin 1995/25 (21) Application number: 93907000.0 (22) Date of filing: 17.02.1993

(51) International Patent Classification (IPC):  G21B 3/ 00( . ) (86) International application number: PCT/US1993/001615 (87) International publication number: WO 1993/017437 (02.09.1993 Gazette 1993/21)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 24.02.1992 US 19920840465 (71) Applicant: ENECO, INC. Salt Lake City, UT 84108 (US)	(72) Inventors: BUSH,Robert T. Upland, CA 91711 (US) EAGLETON,Robert D. Claremont, CA 91711 (US) (74) Representative: Belcher, Simon James  Urquhart-Dykes & Lord Tower House Merrion Way Leeds LS2 8PA Leeds LS2 8PA (GB)