| 摘要 |
1,065,279. Automatic pressure control. WESTLAND AIRCRAFT Ltd. Oct. 8, 1965 [Oct. 14, 1964], No. 41872/64. Heading G3R. Valve means controlling the admission or exhaustion of air to an enclosed space are automatically controlled by electronic means response to the difference between electrical signals representative of a selected pressure and the actual pressure within the space. As described, air is supplied to an aircraft cabin by a blower 64, Fig. 2 (not shown), and the pressure within the cabin is automatically controlled by a combination of five electrical signals controlling the energization of a torque motor 42 which adjusts a cabin exhaust valve 79 through a pneumatic system involving a diaphragm 75 responsive to the pressure difference between the inside and outside of the cabin. One control signal, representing cabin pressure, is obtained by rectifying the output of a moving core transformer associated with an absolute pressure bellows 20. Another control signal, representing the pressure differential between the inside and outside of the cabin, is derived in a similar manner from a differential pressure bellows 54. A third control signal, representing rate of change of cabin pressure, is derived by a resistance-capacity network 44 from the first control signal, and the fourth control signal, representing desired cabin pressure, is derived from an adjustable potentiometer 28. The fifth control signal, which is a velocity feedback signal, is derived by a resistance-capacity network 63 from a potentiometer 61 operated by exhaust valve 79. A detailed circuit involving transistor signal amplifiers, variable attenuators, limiters and a regulated supply, is described. Exhaust valve 79 is closed by operation of a bellows 82 if fall of cabin pressure is excessive, and the valve opens by virtue of a second diaphragm 83 if the pressure outside exceeds that inside sufficiently. Control of the air supply to the cabin instead of the exhaust valve and application to testing and submersible chambers are referred to. |
