| 摘要 |
<p>1,063,747. Automatic temperature control. BARBER-COLMAN CO. June 4, 1965 [Aug.13, 1964], No. 23971/65. Heading G3R. An automatic temperature control system comprises a control unit in the form of a casing which houses all the components of the system with the exception of the final correcting element, the control unit being located so as to be responsive to the temperature being controlled. In a system for controlling the temperature of a room by controlling the flow of a heat exchange fluid the control unit is located in the room. The temperature sensing element is a thermistor forming part of a bridge circuit, another part of which is a manually adjustable potentiometer for setting the desired room temperature. The output of the bridge forms an error signal corresponding in polarity and magnitude to the sense and extent of the temperature error, the error signal being amplified by a transistor amplifier so as to control the value of the current flowing in the final correcting element which is in the form of an electromagnetically operated element which controls a fluid pressure operated valve in a conduit feeding the fluid to a heat exchange means in the room. A bi-metallic switch responsive to the temperature of the fluid in the conduit is effective to reverse the polarity of the direct current feeding the bridge circuit so that the system may be used for cooling instead of heating the room. The casing of the control unit, besides housing the temperature sensing thermistor, the temperature setting potentiometer and the transistor amplifier, also houses potentiometers for adjusting the zero point and the operating range of the system, positive and negative feedback devices which control the gain of the amplifier and introduce an integral term into the amplifier function respectively and a second thermistor which renders the system insensitive to voltage fluctuations.</p> |
