(19)

(11)

EP 0 479 831 A1

(12)

(43) Date of publication: 15.04.1992 Bulletin 1992/16 (21) Application number: 90909581.0 (22) Date of filing: 03.07.1990

(51) International Patent Classification (IPC):  F16L 47/ 04( . ) (86) International application number: PCT/AU1990/000286 (87) International publication number: WO 1991/000470 (10.01.1991 Gazette 1991/02)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI LU NL SE (30) Priority: 03.07.1989 AU 19890005054 (71) Applicant: COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION Campbell, Australian Capital Territory 2601 (AU)	(72) Inventors: JOHNSON, Graham, Michael Ryde, NSW 2112 (AU) QUIGLEY, Suzanne, Margaret Lane Cove, NSW 2066 (AU) NOLAN, Paul, Edward Ohalloran Hill, S.A. 5158 (AU) (74) Representative: Bannerman, David Gardner, et al  Withers & Rogers 4 Dyer's Buildings Holborn London, EC1N 2JT London, EC1N 2JT (GB)