(19)

(11)

EP 0 535 040 A1

(12)

(43) Date of publication: 07.04.1993 Bulletin 1993/14 (21) Application number: 91910939.0 (22) Date of filing: 18.06.1991

(51) International Patent Classification (IPC):  A62C 2/ 06( . ) F16L 5/ 04( . ) (86) International application number: PCT/GB1991/000979 (87) International publication number: WO 1991/019540 (26.12.1991 Gazette 1991/29)

(84) Designated Contracting States: GB (30) Priority: 18.06.1990 GB 19900013533 (71) Applicant: DUFAYLITE DEVELOPMENTS LIMITED St. Neots Cambridgeshire PE19 1QW (GB)	(72) Inventors: GREEN, Dennis William Stapleford, Cambridgeshire CB2 5DT (GB) THWAITES, Peter John Eltisley, Cambridgeshire PE19 4TP (GB) COWLING, Derek Stanley Ramsey, Cambridgeshire PE19 1EL (US) (74) Representative: Gallafent, Richard John  GALLAFENT & CO. 8 Staple Inn London WCIV 7QH London WCIV 7QH (GB)