| 摘要 |
<p>1326715 Tunnel kilns COMPAGNIE GENERALE D'ELECTRO-CERAMIQUE 12 Jan 1971 [14 Jan 1970] 1543/71 Heading F4B In a tunnel kiln for firing ceramic articles, which are supported on a cushion of gas issuing from one or more perforated or porous ceramic hearths 1a, 1b, a mixing chamber 4a, 4b is provided below the or each horizontal or slightly sloping hearth, into which chambers fuel gas from nozzles 5a, 5b, and a forced air supply from nozzles 17 are passed to form the supporting cushion of combustion gases. The mixing chambers may be divided into compartments. The flat or slightly curved hearths may be supported through columns 2 on a support structure, either as shown in the form of assembled blocks 11, or a monolithic structure (Fig. 1, not shown), or the hearth may be combined with the support structure in the form of a hollow box beam (Fig. 3, not shown), assembled beams making up the hearth length. The pressure of the gas supplies through the nozzles 5a, 5b to the mixing chambers 4a, 4b may be periodically oscillated so that an even gas flow over the whole chamber over a given time period is obtained. In an alternative embodiment (Fig. 2, not shown) the fuel gas and air inlet nozzles to the mixing chamber are coaxially arranged and may be aligned with the hearth perforations to minimize gas spread in the mixing chamber. The gas discharge perforations in the hearths may be of divergent or divergent-convergent form. Gases from above the hearths may be withdrawn through the duct between the walls 15a, 156, the injector action of the air jets from nozzles 17 recycling these gases from well 18 up through Venturi passages 12 in the blocks 11 into the mixing chamber 4a, 4b. In modifications (not shown) the supporting gases may be formed by combustion of liquid fuel, or gas to form a cushion may be heated by electrical resistors or inductors. Supplementary burners 10, or electrical resistors or inductors are provided. Flat articles are supported directly by the gas cushion, other articles by an intermediate support plate carried on the gas curtain.</p> |
