GB291909A - Improvements in annealing furnaces - Google Patents

Abstract

291,909. British Furnaces, Ltd., and Smith, E. W., (Surface Combustion. Co.). March 23, 1927. Tunnel annealing-furnaces; muffle furnaces; charging and discharging; charges, conveying.- In a tunnel annealing-furnace, adapted particularly for heating wire coils, of the kind in which the coils 20 are conveyed through the furnace by carriers 38 extending downwardly through a slot 12 in the roof 10, a narrow charging opening 18 is provided in a side wall of the furnace so that the coils can be inserted laterally in an upright position and supported in the path of the travelling carriers 38. The carriage 22 for introducing the charges into the furnace runs on rails 26 and its L-shaped work-supporting portion is provided with an abutment 28, a sealing-plate 32 for the aperture 18, and a slot 30 to permit passage of the carriers 38. The latter are pivoted to arms 36 secured to an endless conveyer 34, the slot 12 in the furnace roof being sealed by the engagement of a channel member, movable with the conveyer 34, in sealing-troughs 62. At the discharge end of the furnace there is provided a hood 46 which extends downwardly below the level of the furnace floor and is fitted with an L-shaped trip member 56 adapted to tilt the carriers 38 to dislodge the coils 20, the carriers being, as shown in Fig. 2, formed with bends 60 to allow them to pass the trip member after discharge of the coil. The coils are received on a truck 48 running on an inclined track 50 and controlled by an endless chain 52. The furnace comprises preheating, heating, and cooling sections A, B. C, the floor 64 and side walls 66 of the sections A, B being formed of thin carborundum and spaced from the base 68 and outer walls 70 respectively to provide heating passages Burners 80 deliver into the space below the floor 64 which is supported on longitudinal piers 82 of which those in the sections B are formed with openings 84 to allow the gases to pass into the side heating passages 86. These passages are separated from similar passages 96 in the preheating zone A by a vertical partition 72, both passages 86, 96 being provided with horizontal baffles 90, 98 respectively to cause the gases to take the zig-zag course shown by the arrows in Fig. 1, before escaping through side flues 100 to the chimney 101.