(19)

(11)

EP 0 203 131 A1

(12)

(43) Date of publication: 03.12.1986 Bulletin 1986/49 (21) Application number: 85905858.0 (22) Date of filing: 21.11.1985

(51) International Patent Classification (IPC):  G01R 21/ 127( . ) G01R 21/ 133( . ) (86) International application number: PCT/GB1985/000535 (87) International publication number: WO 1986/003302 (05.06.1986 Gazette 1986/12)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 24.11.1984 GB 19840029752 (71) Applicant: CREST ENERGY SCAN LIMITED Cheshire SK6 6AW (GB)	(72) Inventor: AMBLER, Arnold Edward Cheshire SK6 6PJ (GB)