GB745301A - Improvements in or relating to metal heating furnaces - Google Patents

Abstract

745,301. Discharging metal heating furnaces. FUEL FURNACES, Ltd. July 19, 1954 [April 18, 1953], No. 10670/53. Class 51 (2). In a heat treatment furnace of the type in which hot, treated work pieces are discharged from the treatment chamber intermit - tently or continuously into a shoot, work pieces, such as metal rivets, conveyed through the furnace by a succession of tilting trays 1 as disclosed in Specification 599,914, are discharged from a space 4 between doors 5 and 6 into a cooling shoot 3 formed with three sliding dampers 15, 16 and 17 operated in sequence by hydraulic or pneumatic cylinders 20. The dampers engage grooves 18 in the walls of the shoot, and to prevent small articles being lodged therein, the edges of the grooves may be inclined downwardly towards the shoot end. A pipe 21 for the-supply of a raw gas at a greater than atmospheric pressure is disposed above the lowest damper 17. Work pieces cool enough to avoid oxidation and other deleterious effects are discharged through the damper 17 from the shoot 3 onto a conveyer 8 arranged in a tunnel 9 alongside the furnace and are cooled further by air drawn along the tunnel by a fan 13 at the end of a duct 12. A damper-controlled flue 10 joins an exhaust chamber 7 for the furnace gases to the duct 12, and the combined hot gases and air stream is discharged into a chimney 14.