| 摘要 |
PURPOSE:To ensure high response to a change in the extent of evaporation by a rapid change of a shutter by comparing the opening degree of the shutter placed at the outlet of an evaporation tank with a standard and by changing the power of a heater when the difference exceeds the permitted limit. CONSTITUTION:The opening degree of a shutter 8 for regulating the feed of metallic vapor 3 generated from a metallic bath 1 is measured. When the difference between the measured value and a prescribed value is within the permitted limit, the bath 1 is continuously heated with a heater 4. When the difference is positive and is above the permitted difference, the temp. of the bath 1 is lower, so the power of the heater 4 is increased to raise the temp. of the bath 1. When the difference is negative and is below the permitted difference, the temp. of the bath 1 is higher, so the power of the heater 4 is reduced to drop the temp. of the bath 1. Thus, the instantaneous control of the extent of evaporation with the shutter is continuously carried out.
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