(19)

(11)

EP 0 553 144 A1

(12)

(43) Date of publication: 04.08.1993 Bulletin 1993/31 (21) Application number: 91917676.0 (22) Date of filing: 04.10.1991

(51) International Patent Classification (IPC):  C03B 7/ 10( . ) (86) International application number: PCT/GB1991/001725 (87) International publication number: WO 1992/006045 (16.04.1992 Gazette 1992/09)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 05.10.1990 GB 19900021682 (71) Applicant: BH-F(ENGINEERING) LIMITED Abingdon, Oxfordshire OX14 4SE (GB)	(72) Inventor: ANDERSON, Lars Tore Didcot, Oxon OX11 0BJ (GB) (74) Representative: Gallafent, Richard John  GALLAFENT & CO. 8 Staple Inn London WCIV 7QH London WCIV 7QH (GB)