(19)

(11)

EP 0 456 710 A1

(12)

(43) Date of publication: 21.11.1991 Bulletin 1991/47 (21) Application number: 90902805.0 (22) Date of filing: 31.01.1990

(51) International Patent Classification (IPC):  G01J 1/ 02( . ) G01J 1/ 44( . ) G01J 1/ 42( . ) (86) International application number: PCT/GB1990/000138 (87) International publication number: WO 1990/008946 (09.08.1990 Gazette 1990/19)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI LU NL SE (30) Priority: 31.01.1989 GB 19890002080 (71) Applicant: YORK LIMITED Chandler's Ford Hampshire SO5 3DG (GB)	(72) Inventor: DAKIN, John, Philip East Wellow Romsey SO5 0BN (GB) (74) Representative: Cullis, Roger  Patents Department British Technology Group Ltd 101 Newington Causeway London SE1 6BU London SE1 6BU (GB)