GB1078522A - Improvements in pottery kilns - Google Patents

Abstract

1,078,522. Continuous kilns. WEST MIDLANDS GAS BOARD, and JOHNSON BROS. (HANLEY) Ltd. Dec. 24, 1963 [Sept. 25, 1962], No. 28528/62. Heading F4B. A continuous pottery kiln comprises a single passage 13 along which ware is moved through preheat, firing and cooling zones on batts 42 spaced from the floor of the passage on mountings which afford slidable, guided support of the batts, the firing zone being provided with longitudinal combustion chambers for transmitting a variable quantity of heat through at least the floor and side walls of the passage. Side combustion chambers 15 and a floor combustion chamber 18 extend through the firing zone, Fig. 8, and the preheat zone, Fig. 4, and comprise channels with their open sides facing the passage 13, said open sides being closed by inclined rows of overlapping refractory tiles 17 in the case of chambers 15 and by the batts 42 and stretchers 41 in the case of chamber 18. Burners 20 introduce gaseous fuel into the combustion chambers near the ware exit end of the firing zone and secondary air is supplied between the burners and the cooling zone, Fig. 7 (not shown). The primary and secondary air supplies together with a tertiary air supply which may be provided in the firing zone are controlled by valves or dampers (not shown). An additional burner (not shown) is provided in the floor combustion chamber midway along the firing zone. The gas/air mixtures of each burner can be regulated independently, which regulation may be automatic. Additional combustion chambers may be provided in the passage roof 19. The cooling zone comprises initial rapid cooling, slow cooling, and final rapid cooling stages. The two rapid cooling stages are of similar construction and, as shown in Fig. 12, comprise a muffle 23 cooled by air introduced into space 25 through passages 26 fitted with plugs 27 enabling the air circulation in space 25 to be controlled. The air may be forced through passages 26 by fans. In the final rapid cooling stage air passages 29 open into the passage 13. The are is cooled in the slow cooling stage by a flow through passage 13 induced by a blower (not shown) and an exhaust system 32 at the ware exit and entry ends of said passage respectively. The exhaust system 32 withdraws not only the air in the passage but also the gases in combustion chambers as shown in Fig. 4. The suction in the exhaust system is produced by fans (not shown) and automatically regulated by dampers (not shown). Three recirculation units 33 spaced along the length of the pre-heat zone include fans which draw heated air from the top of the passage and reintroduce it at floor level. Independently operable dampers can be used to regulate the amount and place of withdrawal and re-introduction of heated air. The batts 42 are provided with overlapping rebated portions and are supported by stretchers 41 which slide in two parallel grooves 40 which are provided with rollers at the entry and exit ends of the passage, Figs. 3 and 11 (not shown). One or more of the tiles 17 may be removed in the preheat section to obtain therein a steeper temperature gradient.