| 摘要 |
PURPOSE:To prevent the seizure of a concn. boiler and to enhance working efficiency by enlarging the tolerant limit operation range of a concn. apparatus, in performing the operation of a membrane falling type concn. boiler, by controlling the inflow amount of the raw solution from an inlet by a relatively simple control method. CONSTITUTION:In order to prevent the seizure in a membrane falling type concn. boiler 11 by controlling the flow amount of a raw solution at the inlet of said boiler 11, at first, the concn. D0 of the concn. solution in the outlet pipe 13 of the concn. boiler 11 and the evaporation amount G0 in a vapor pipe 15 are detected. The flow amount of the concn. solution per the unit peripheral length of the heat transfer surface in the concn. boiler 11 is calculated by operating said detected values by an operator 18 and subjected to the comparison operation with the solution amount of the conc. solution per a predetermined unit peripheral length required in preventing the seizure and output y1 for determining the min. necessary inlet flow amount F1 of the raw solution is operated on the basis of the operated values. On the other hand, output MV for determining the flow amount F1 required in holding the concn. D0 of the outlet conc. solution to a predetermined value is operated and the outputs y1 MV are subjected to comparison operation in an operator 19 to output a value for increasing F1 as y2 while the set value of the inlet flow amount of the raw solution is controlled by y2 and the inlet flow amount F1 of the raw solution is controlled by the controlled set value.
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