GB254023A - Improvements in kilns or ovens for baking pottery or the like - Google Patents

Abstract

254,023. Arleux, R. M. d', and Violette, E. March 28, 1925. Tunnel kilns.-In tunnel kilns for baking pottery having movable hearths on which the articles are heated by direct exposure to the flame, a mixture of gaseous fuel and air, which may be prepared in the manner described in Specification 162,276, is introduced through tuyeres having a thermosyphonic circulating cooling system, a pressure greater than atmospheric being maintained in the kiln. The movable, bottom 12 of the oven is constituted by trucks 13 which run in the direction of the arrow 14 and have flanges 42 fitting in sand grooves 43. Parallel to the axis of the tunnel are fitted a number of tuyeres 19 with water-cooling jackets 20 connected by a thermosyphon 22 to a reservoir 21, these burners are provided in such number and size in relation to the capacity of the hearth and the pressure of the fuel supply that combustion takes place under pressure. A sloping fire-resisting surface 25 in front of the burners breaks the jets of flame. The articles after passing through the preheating zone 15 and firing zone 16 pass under a low vault 27 and the cooling air blown in at the exit end 28 of the kiln is by-passed through a flue 29 connected with a chimney 30 before reaching this vault so that there is no circulation of air in the chamber 17 beneath the vault. In the chamber 32 above the vault 27, which is partly formed of thin slabs 31, the air is further heated and then passes through the flue 29 to a chamber 33 through which pass pipes 34 connected to thetuyeres 19 and supplied with the fuel mixturefrom a header 35. Part of the cooling air may be withdrawn through a duct 38 and conveyed. through channels 39, 40 to the part 41 of the kilnwhen it is desired to obtain an oxidizing atmosphere at this part.