(19)

(11)

EP 0 502 982 A1

(12)

(43) Date of publication: 16.09.1992 Bulletin 1992/38 (21) Application number: 91901103.0 (22) Date of filing: 28.11.1990

(51) International Patent Classification (IPC):  F28F 13/ 12( . ) (86) International application number: PCT/US1990/006957 (87) International publication number: WO 1991/008433 (13.06.1991 Gazette 1991/13)

(84) Designated Contracting States: DE FR GB SE (30) Priority: 29.11.1989 US 19890443218 12.04.1990 US 19900508962 28.09.1990 US 19900590342 (71) Applicant: DIERBECK, Robert F. Hartford, WI 53027 (US)	(72) Inventor: DIERBECK, Robert F. Hartford, WI 53027 (US) (74) Representative: Prutton, Roger, et al  MARKS & CLERK, Alpha Tower, Suffolk Street Queensway Birmingham B1 1TT Birmingham B1 1TT (GB)