(19)

(11)

EP 0 895 580 A1

(12)

(43) Date of publication: 10.02.1999 Bulletin 1999/06 (21) Application number: 97919534.0 (22) Date of filing: 23.04.1997

(51) International Patent Classification (IPC):  G01F 1/ 58( . ) (86) International application number: PCT/GB1997/001126 (87) International publication number: WO 1997/041407 (06.11.1997 Gazette 1997/47)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 26.04.1996 GB 19960008668 (71) Applicant: Caledonian Control Technology Limited Redditch, Worcestershire B97 4AJ (GB)	(72) Inventor: PATRICK, Bernard John Corley, Warwickshire CV7 8BE (GB) (74) Representative: Lishman, Peter David, et al  Aston Farm House Newtown Lane Shustoke Coleshill Warwickshire B46 2SD Coleshill Warwickshire B46 2SD (GB)