(19)

(11)

EP 0 527 863 A1

(12)

(43) Date of publication: 24.02.1993 Bulletin 1993/08 (21) Application number: 91909185.0 (22) Date of filing: 17.05.1991

(51) International Patent Classification (IPC):  C21C 5/ 46( . ) C21C 5/ 50( . ) (86) International application number: PCT/GB1991/000782 (87) International publication number: WO 1991/018119 (28.11.1991 Gazette 1991/27)

(84) Designated Contracting States: AT BE DE ES FR GB IT LU NL SE (30) Priority: 18.05.1990 GB 19900011224 (71) Applicant: DAVY MCKEE (STOCKTON) LIMITED Stockton-on-Tees Cleveland TS18 3RE (GB)	(72) Inventors: HIBBS, Michael Rozel Tame Bridge Cleveland TS9 54Q (GB) BAILEY, Ralph Co Durham DL5 4EU (GB) (74) Representative: Kirk, Geoffrey Thomas  BATCHELLOR, KIRK & CO. 2 Pear Tree Court Farringdon Road London EC1R 0DS London EC1R 0DS (GB)