(19)

(11)

EP 0 420 904 A1

(12)

(43) Date of publication: 10.04.1991 Bulletin 1991/15 (21) Application number: 89907235.0 (22) Date of filing: 19.06.1989

(51) International Patent Classification (IPC):  B01L 11/ 00( . ) B01L 7/ 00( . ) (86) International application number: PCT/GB1989/000684 (87) International publication number: WO 1989/012502 (28.12.1989 Gazette 1989/30)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 23.06.1988 GB 19880014962 (71) Applicant: LEP SCIENTIFIC LIMITED Milton Keynes, Buckinghamshire MK14 6QF (GB)	(72) Inventor: CAVE, John Luton, Bedfordshire LU3 3SL (GB) (74) Representative: Brooks, Nigel Samuel  Hill Hampton East Meon Petersfield Hampshire GU32 1QN Petersfield Hampshire GU32 1QN (GB)