| 摘要 |
1,006,511. Electric positional control. CONTROLE BAILEY. July 26, 1962 [Aug. 11, 1961], No. 28816/62. Heading G1N. In a servo-mechanism, the position of a spring-loaded shaft 7 is determined by the differential vapour pressure of condensable fluid such as butane in two compartments 12,13 of a cylinder 1 separated by a piston 8 connected to shaft 7, the fluid in compartment 13 being heated or cooled by a Peltier effect thermopile 3 in accordance with the sense and magnitude of the supply current to the thermopile, which is the amplified algebraic sum of a control signal applied at terminals 19 and a shaft position feedback signal produced by a differential transformer 15 and rectified by bridge 17. The cylinder 1 and piston 8 are heat-insulated at 4 and 9, while thermal contact between the fluid in compartment 13 and the thermopile is enhanced by fins 14. A compressible material of low thermal conductivity may be disposed in chamber 13 to retard heat transfer when the upper surface of the thermopile is the cooler. In a modification adapted for use with a unidirectional error current, the thermopile is mounted in the piston, and the bottom compartment, which is normally the hotter, contains a compressible substance having good thermal conductivity e.g. metal shavings. |
