GB449116A - Improvements in tunnel kilns - Google Patents

Abstract

449,116. Tunnel kilns. TECHNOTHERMIE SOC. A R.L., 126, Rue Lafayette, Paris. July 2, 1935, Nos. 18918 and 18919. Convention dates, July 2, 1934 and June 5, 1935. [Classes 51 (i) and 51 (ii)] In a tunnel kiln heated by vertically - delivering burners 12 distributed along the firing- zone C of the kiln, the air for combustion being supplied through heat-exchange passages 6 at the sides of the cooling-zone D, the crosssectional area of each of these passages increases from the discharge end of the kiln in order to accommodate the greater volume of the air, as its temperature is raised, and delivery of the air is effected through horizontal conduits 11 extending beneath the burners and connected thereto by vertical ports 13. Vertical baffles may be fitted in the passages 6 to cause the air to follow a zigzag path. The connection between the passages 6 and conduits 11 may be made by downwardly-inclined flues 10 of tapering form, and the conduits 11 may be extended beyond the firing zone so that hot air can be supplied to the preheating and drying zones B, A, at the junction of which the exhaust flue 9 is situated. Cooling-air is also passed through a flue in the roof of the cooling-zone, and is either delivered to atmosphere or used in drying - rooms. Staggered partitions 22, 221 in the preheating-zone cause the heating-gases to follow a sinuous course. To facilitate the circulation of heating-gases beneath the goods the truck platforms are formed of spaced refractory elements. Gaseous-fuel fittings.-The gas burner ports comprise a refractory block 26 formed with tapering nozzles 27 which project into converging apertures in a refractory plate 28. Gas is supplied to the space 25 around the nozzles 27 which communicate with the vertical ducts 13 leading from the air conduits 11. The nozzles may be staggered in two rows, and they may have helical ribs both inside and outside to impart a whirling motion to the fuel and air. Gas is supplied from a main 16 through a pipe 17 having an inspection aperture 19.