| 摘要 |
<p>An air conditioning control system for at least two duct sections each with an associated damper comprises at least one master controller for a first pneumatic actuator for one damper and at least one tracking controller for a second pneumatic actuator for the other damper. The master controller comprises a first flow sensor producing a first flow variable signal in response to a sensed flow in the duct section associated with the said one damper. An adjustable reference or bias signal means is provided and a temperature signal is combined therewith to provide a composite signal for comparison with the flow variable signal. A resultant signal after comparison operates the first pneumatic actuator for the said one damper. A tracking controller comprises a second flow sensor producing a second flow variable signal in response to sensed flow in the duct section associated with the other damper. A second signal comparison and transmitting means receives the first and second flow variable signals, compares the two and transmits a second resultant signal to the second pneumatic actuator for control of the said other damper. The second comparison means includes a pivotally mounted lever acted upon by diaphragm actuated first and second push rods representing the first and second flow variable signals. One of the diaphragm assemblies is mounted for slidable adjustment along the lever to vary the relative mechanical advantage and to vary the flow ratio between the two dampers and duct sections.</p> |
