Abstract
THE new pottery factory of Messrs. Josiah Wedgwood and Sons, Ltd., at Barlaston, has been described in articles in the Electric Review of April 18 and May 2. For the first time in Great Britain, electrical biscuit and glost firing have been combined in one kiln. In biscuit firing the pottery is subjected to direct radiation from the source of heat instead of being stacked in the kiln in special containers (saggars). Both the biscuit and glost firing are effected in a double tunnel kiln of the conveyor type. The two tunnels—one biscuit and one glost—are side by side, so as to reduce construction costs and effect a measure of heat recuperation. In each tunnel there are a heating–up and a cooling–down section at opposite ends of the firing zone, and the sequence in the case of biscuit firing is opposite to that of glost firing. The overall length of the kiln is 272 ft. and the firing zone is about 100 ft. long. Each tunnel measures about 6 ft. by 4 ft. inside, just a little larger than the trucks which convey the wares through the kiln. The firing zone of each tunnel has a number of sections, the temperatures of which, as recorded by pyrometers on the outside walls and at the centres of the sections, follow a desired curve in each case, with a maximum in the case of biscuit firing of about 1,150° C. ‘Kanthal’ type or aluminium–iron elements consisting of strip about ½ in. wide wound spirally on a refractory former about 3 ft. long are used. Trucks carrying the pottery run on rails continuously through the kiln end to end as a train, the whole being propelled by a pusher unit, which operates with the end truck at the tunnel entrance. Enamelling firing for colour work demands a temperature of about 850° C., which is low in comparison with biscuit and glost firing. The enamel firing is also done electrically, but this is not a new development although the kiln used for the purpose is new.
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Electric Heating in the Pottery Industry. Nature 148, 21–22 (1941). https://doi.org/10.1038/148021b0
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DOI: https://doi.org/10.1038/148021b0