| 摘要 |
<p>A control for an air conditioning system comprises a flow sensor and a condition sensor in the form of a thermostat controlling a pivotal lever which in turn sets a pressure at a control orifice for an actuator which operates the control damper in an air supply duct. The flow signal is obtained by upstream and downstream pressure taps adjacent an orifice in the duct and the temperature signal is obtained in a conventional manner and applied to the pivotally supported control lever via a diaphragm, push rod, reset spring, etc. In order to enhance the operating range of the control a variable area orifice means is provided and may comprise a pair of swingable vanes adjacent the fixed orifice and the upstream and downstream pressure taps. The vanes may be moved to open and closed positions, modulated therebetween and they may be under the control of an on-off manual valve or alternatively they may respond to the second condition or temperature sensor.</p> |
