(19)

(11)

EP 0 080 466 A1

(12)

(43) Date of publication: 08.06.1983 Bulletin 1983/23 (21) Application number: 82901526.0 (22) Date of filing: 28.05.1982

(51) International Patent Classification (IPC):  F15B 15/ 28( . ) (86) International application number: PCT/GB1982/000157 (87) International publication number: WO 1982/004293 (09.12.1982 Gazette 1982/29)

(84) Designated Contracting States: AT CH DE FR GB LI LU NL SE (30) Priority: 28.05.1981 GB 19810016323 (71) Applicant: PRUTEC LIMITED London EC1N 2NH (GB)	(72) Inventors: ARCHER, John Richard Fowlmere, Royston Hertfordshire (GB) TARGELL, David John Bar Hill, Cambridge (GB)