| 摘要 |
1487672 Pneumatic thermostat POWERS REGULATOR CO 9 July 1975 [9 April 1975] 28907/75 Heading G 1D [Also in Division G3] A pneumatic thermostat comprises means for receiving a variable pressure air supply, means for generating from said supply a substantially constant pressure air-flow which is received in a first chamber, and temperature responsive means disposed within a thermometric chamber which adjusts the pressure in the first chamber in response to changes in ambient temperature. An outlet communicating with the first chamber is provided for transmitting a pressure signal indicative of the ambient temperature, and an aspirator is further provided for drawing ambient air through both the interior of the thermometric chamber and a space immediately adjacent the exterior of the thermometric chamber. As described, the thermometric chamber 250 is part of a heat sensing and aspirating component 200 that is mounted at one end of a terminal diffuser 202 positioned in the ceiling 204 and engaged with a discharge duct 206 of an air distribution system. The provision of an aperture 252, Figure 9 allows aspirator 260 to draw ambient air through space 212 to eliminate spurious heating of the temperature sensitive element due to the proximity of duct 206. The temperature sensitive element is a bi- metallic lever 153 which regulates the air discharge from nozzle 142. Air at pressure P 1 flows into a lower section 131 of pressure reducing chamber 130, and bleeds, via a ball and seat arrangement, into an upper section 132 communicating with the air distribution system which is at pressure P 2 . A substantially constant reduced pressure P r is thus maintained within section 131 which section communicates with pressure transmitting chamber 140 via aperture 139. Conduit B connects chamber 140 with chamber 150 via the nozzle 142 so that the air discharge from the nozzle which varies with ambient temperature is experienced as a pressure signal P c in chamber 140 and transmitted to a flow regulater by conduit 116. Reference has been directed by the Comptroller to Specification 1434803.
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