(19)

(11)

EP 0 613 525 A1

(12)

(43) Date of publication: 07.09.1994 Bulletin 1994/36 (21) Application number: 92923895.0 (22) Date of filing: 23.11.1992

(51) International Patent Classification (IPC):  F04B 1/ 20( . ) F04B 1/ 12( . ) (86) International application number: PCT/GB1992/002160 (87) International publication number: WO 1993/010349 (27.05.1993 Gazette 1993/13)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 21.11.1991 GB 19910024717 (71) Applicant: J.H. FENNER & CO. LIMITED Wellton Brough, North Humberside HU15 1PQ (GB)	(72) Inventor: SEABROOK, Colin Driffield North Humberside YO25 9HS (GB) (74) Representative: W.P. THOMPSON & CO.  Kings Building, South Church Side Hull, North Humberside HU1 1RR Hull, North Humberside HU1 1RR (GB)