(19)

(11)

EP 1 000 322 A1

(12)

(43) Date of publication: 17.05.2000 Bulletin 2000/20 (21) Application number: 99901009.3 (22) Date of filing: 18.01.1999

(51) International Patent Classification (IPC)7: G01F 1/58 (86) International application number: PCT/GB9900/032 (87) International publication number: WO 9936/749 (22.07.1999 Gazette 1999/29)

(84) Designated Contracting States: CH DE ES FR GB IT LI NL SE (30) Priority: 17.01.1998 GB 9800952 (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  Aston Farm HouseNewtown LaneShustoke ColeshillWarwickshire B46 2SD ColeshillWarwickshire B46 2SD (GB)