| 摘要 |
The apparatus includes a plurality of extruders which feed parallel streams or ribbons of raw material or charge along rollers through successive chambers in a kiln and through an annealing lehr to zones to where the material is cut. The surfaces of the raw material are coated on three sides with a parting or releasing agent and, on the side to be exposed, with a glaze or engobe, or left uncoated. The firing chamber of the kiln has opposed rows of fuel burners on the sides directed toward ports on the other side and refractory rollers which protrude through the side walls and are supported on circumferentially spaced wheels. Wheels between adjacent ends synchronize rotation of the rollers. Manifolds feed the stack gases from the firing chamber into the preheating chamber. The process includes using charges which are either a mixture of a small amount of soluble carbonaceous material and water to adjust the carbon and moisture content of the clay or silica with carbonaceous material and water. If the charge is clay, it is then extruded as ribbons, coated with releasing agent and glaze or engobe, then dried, preheated, sintered, fired at above about 2000 DEG F. and annealed. Cellulated vitreous clay product results which is cut into rectangular blocks. If the charge is silica, no annealing is required and normally a glaze formed by silica sand may be applied to a surface thereof. The silica charge is produced by pressing simultaneously the silica charge and a material for a plate rather than being extruded, successive plates being passed through the kiln to cellulate and vetrify.
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