(19)

(11)

EP 2 052 220 A1

(12)

(43) Date of publication: 29.04.2009 Bulletin 2009/18 (21) Application number: 06765090.3 (22) Date of filing: 21.07.2006

(51) International Patent Classification (IPC):  G01F 1/66(2006.01) (86) International application number: PCT/GB2006/002763 (87) International publication number: WO 2008/009870 (24.01.2008 Gazette 2008/04)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR Designated Extension States: AL BA HR MK RS (71) Applicant: Sentec Limited Cambridge CB5 8EG (GB)	(72) Inventors: COLBY, Edward Cambridge CB4 3AH (GB) SYROP, Alan Herts SG8 5UP (GB) ROUSSOPOULOS, Kimon Cambridge CB4 1NE (GB) (74) Representative: Wilson, Peter David George  ip21 Limited Norwich Research Park Colney GB-Norwich NR4 7UT GB-Norwich NR4 7UT (GB)