| 摘要 |
1,223,949. Gas analysis; correspondence control. FARBENFABRIKEN BAYER A.G. July 7, 1969 [July 8, 1968], No. 34124/69. Headings G1B and G1N. Apparatus for metering gases in gas analysis operations comprises a cyclically operating gas delivery pump delivering a constant volume of gas for making cycle and driven by an electric motor, the speed of rotation of which is controlled by the frequency of the A.C. supply to the motor, a temperature sensor, e.g. a temperature sensitive resistance in the pump to sense gas temperature and providing a signal for varying the frequency of the motor supply current in a sense so as to produce a gas delivery of constant mass per unit time. In this way a constant mass of gas is obtained irrespective of temperature changes by varying the speed of operation of the pump.
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