| 摘要 |
PURPOSE: To satisfactorily tumble objects to be dried and to eliminate non-uniformity in drying by arranging a control system for variably controlling the number of rotations per unit time of a drum corresponding to the detecting signals of temperature near an air inflow to the drum and temperature or humidity near an air outflow. CONSTITUTION: After the start of operation, while keeping the number of rotations per unit time of the drum of f1 , a drum exit temperature To and a heater entrance temperature Ti detected by sensor parts 17 and 18 are transited with a fixed temperature difference for a while. After time t0 , a temperature difference (To -Ti ) starts increasing and at time t1 , the temperature difference (To -Ti ) gets equal withΔT1 preset by a control circuit 19. Then, a frequency down command is outputted from the control circuit 19 to an inverter circuit and operation is performed while keeping the number of rotations per unit time of the drum of f2 just for certain fixed timeΔt. In this case, the tumbling of objects to be dried in the drum is made satisfactory. Such operation is repeated several times, the objects to be dried are dried without non-uniformity, the temperature is elevated without lowering the exit temperature To and at the time when the temperature difference (To -Ti ) becomesΔTs (at time t4 ), drying is finished.
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