(19)

(11)

EP 0 640 123 A1

(12)

(43) Date of publication: 01.03.1995 Bulletin 1995/09 (21) Application number: 93911874.0 (22) Date of filing: 27.04.1993

(51) International Patent Classification (IPC):  C02F 3/ 22( . ) C12M 3/ 02( . ) C12M 1/ 04( . ) (86) International application number: PCT/GB1993/000875 (87) International publication number: WO 1993/022418 (11.11.1993 Gazette 1993/27)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI NL PT SE (30) Priority: 28.04.1992 GB 19920009175 (71) Applicant: PIRTFERM LIMITED Putney, London SW15 6HG (GB)	(72) Inventor: PIRT, Stanley, John 50 Chartfield Avenue London SW15 6HG (GB) (74) Representative: Holmes, Michael John  Frank B. Dehn & Co. European Patent Attorneys Imperial House 15-19 Kingsway London, WC2B 6UZ, London, WC2B 6UZ, (GB)