| 摘要 |
1522498 Temperature control apparatus for dewpoint measurement COMPTEURS SCHLUMBERGER 21 Oct 1975 [23 Oct 1974] 43197/75 Heading G1A The temperature of a body 2 is maintained at a required value by the conjoint action of heating and cooling means operating in 'push-pull'. The described system is designed for application to a dew-point hydrometer. In Fig. 1, the presence or absence of dew on a surface 11 of the body is sensed by a lamp-and-photo-cell arrangement 12, 14 which provides an output 6 controlling, via a transistor 19, the current supply to a heater 15. As the heating current rises or falls, the output between the transistor's collector and emitter respectively falls or rises. This output in turn controls, via the circuitry shown, a Peltier effect cooler 21. The same apparatus may be operated the other way, viz the cooling be controlled directly and the heating effect made dependent on a measurement of the cooling power. Fig. 2 (not shown) is substantially the same as Fig. 1 but uses a fluid-circuit refrigerator in place of the Peltier effect cooler. |
