| 摘要 |
<p>1, 016, 696. Photo-electric control apparatus. FOSTER INSTRUMENT CO. Ltd. Sept. 7, 1962 [Sept. 8,1961], No. 32298/61. Heading G1A. [Also in Division G3] The invention relates to apparatus for comparing the intensity of a test source, for example a furnace, with that of a comparison source wherein the comparison signal is used to control or measure the intensity of the test source, for example to control the power input to the furnace (Fig. 1) or to continuously indicate its temperature (Fig. 2) (not shown). As shown in Fig. 1 the photo-resistor 11 receives radiation (visible or otherwise) alternately from the furnace 10 and the lamp 12 by means of the rotating apertured disc 14. The motor 13 controlling the disc 14 also controls the switching amplifier 15 receiving the pulsed output from the photo-resistor 11 whereby the pulses from one or other of the sources 10,12, are reversed in polarity. The mean output of the alternate positive and negative pulse train is indicated in the meter 17 and is applied to the control amplifier 18 to control the power input to the furnace 10. The arrangement in Fig. 2 (not shown) differs in that the output from the amplifier 18 controls the intensity of the lamp 12 to give zero output from the amplifier 15 thus giving an indication of the temperature of the furnace. A control signal may also be applied from the indicator 21 to the surface 10 if the furnace temperature departs from a predetermined range. Each embodiment may include a filter 22 to select monochromatic radiation.</p> |
