1,098,551. Slag tap gasifiers. C.U.R.A. PATENTS Ltd. Oct. 5, 1964 [July 4, 1963], No. 26645/63. Heading F4B. In a fixed bed solid fuel gasifier housing a slag outlet 7 at its lower end and tuyeres 9 entering the bed of solid fuel near the base of the gasifier, the distance between the nozzle 11 of at least one of the tuyeres and the slag outlet 7 can be varied during operation. The gasifier may have a number of radially directed tuyeres extending into the shaft for the same distance, or radially directed tuyeres which extend into the shaft for different distances. In a modification, the tuyeres are directed tangentially to a firing circle within the shaft, a central reactant gas supply is provided, and the gasifier has a number of slag outlets midway between the axis and periphery of the shaft. The retractable tuyeres, Fig. 3, have auxiliary gas supply pipes 21 with chamfered ends serving to throttle the nozzles 11, and cooling tubes 30, 33 surrounding the retractable nozzle part 24 and that part of the tuyere body 13 projecting into the furnace. The nozzle part 24 and supply pipe 21 are slidable within the body part, and may be controlled automatically in accordance with the temperature indicated by a radiometer positioned at the end of a quartz rod inserted into the shaft. The central gas supply assembly may have a number of separate nozzles, and may be axially adjustable and rotatable. A further form of central gas outlet (Fig. 6, not shown) has a water-cooled mushroom cap spaced from a water-cooled body to have a slot which is cleaned by scraper arms. The assembly is secured in the shaft by a bellows sealing arrangement to allow of its axial adjustment.
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