| 摘要 |
A system for controlling the starting time of a thermal conditioning system for air in an enclosed space includes a pneumatic temperature transmitter, a pressure chamber, bleed device, and a valve for selectively providing communications either between the temperature transmitter and the pressure chamber (first position) or the pressure chamber and bleed device (second position). When a timing device is turned off at a predetermined time the valve is actuated into the first position. The pressure in the pressure chamber then rises and actuates a switch to shut off the thermal conditioning system. The pneumatic temperature transmitter then senses a temperature which is indicative of the amount of thermal conditioning necessary to bring the temperature of the air in the enclosed space to a desired level by a predetermined time and generates in response thereto an air pressure signal. The air pressure signal is continuously passed to the pressure chamber so that the pressure in the pressure chamber becomes the same as the pressure of the air pressure signal. At a predetermined time the valve is actuated to the second position and air is permitted to bleed until a predetermined pressure is reached in the pressure chamber, which actuates the switch turning on the thermal conditioning system.
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