(19)

(11)

EP 0 513 294 A1

(12)

(43) Date of publication: 19.11.1992 Bulletin 1992/47 (21) Application number: 91920894.0 (22) Date of filing: 02.12.1991

(51) International Patent Classification (IPC):  C01F 7/ 00( . ) C11D 3/ 12( . ) C11D 3/ 00( . ) (86) International application number: PCT/GB1991/002125 (87) International publication number: WO 1992/009529 (11.06.1992 Gazette 1992/13)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI NL SE (30) Priority: 03.12.1990 GB 19900026230 (71) Applicant: JOSEPH CROSFIELD & SONS Warrington WA5 1AB (GB)	(72) Inventors: COCKETT, Keith, Robert, Fraser 6 Tunnel End Cheshire WA4 4JX (GB) CONCANNON, Martin 35 Grange Farm Crescent Merseyside L48 9YD (GB) WEBB, Maurice Cheshire CH3 5LD (GB) (74) Representative: Hugot, Alain  Patent Division, Colworth House Sharnbrook, Bedford MK44 1LQ Sharnbrook, Bedford MK44 1LQ (GB)