(19)

(11)

EP 0 042 396 A1

(12)

(43) Date of publication: 30.12.1981 Bulletin 1981/52 (21) Application number: 81900067.0 (22) Date of filing: 17.12.1980

(51) International Patent Classification (IPC):  B01F 3/ 04( . ) B01F 5/ 10( . ) B01F 5/ 04( . ) C02F 3/ 12( . ) (86) International application number: PCT/GB1980/000217 (87) International publication number: WO 1981/001700 (25.06.1981 Gazette 1981/15)

(84) Designated Contracting States: DE FR NL SE (30) Priority: 18.12.1979 GB 19790043493 (71) Applicant: BOC Limited London W6 9DX (GB)	(72) Inventors: KEENE, Richard Michael Banstead Surrey (GB) KITE, Oliver Anthony West Wickham Kent (GB) GARRETT, Michael Ernest Woking Surrey (GB)