PROCESS AND APPARATUS FOR CONTROLLING OPENING AND CLOSING OF SPRAY NOZZLE IN SPRAY DRYING TOWER

摘要

PURPOSE:To obtain a product having stable quality without impairing thermal efficiency and uniformity of spray by opening or closing a spray nozzle in a short time and changing a spray pattern to an almost uniform state in a short time even in a case of causing clogging of nozzle. CONSTITUTION:Plural numbers of spray nozzle 2 arranged to a specified positional relation selectively to operate to perform uniform spray from these nozzles 2 by opening or closing a feed valve 8 by the operation of a controlling device 14 in accordance with a program for obtaining uniform spray pattern of slurry. If any one of the nozzles 2 is closed by clogging during spraying, the feed valve 8 is closed in accordance with an output signal from a clogging detector 13, and a water feed valve 11 is opened simultaneously to perform washing of the clogged spray nozzle 2. At the same time, another nozzle 2 not in operation is opened as a substitute nozzle 2 for the clogged nozzle 2 so far as the uniform spray pattern of slurry can be maintained.