Method and measuring device for determining the water content of a gas

摘要

PCT No. PCT/DE96/01163 Sec. 371 Date Feb. 26, 1997 Sec. 102(e) Date Feb. 26, 1997 PCT Filed Jun. 26, 1996 PCT Pub. No. WO97/02486 PCT Pub. Date Jan. 23, 1997The invention concerns a method and measuring device for determining the water content of a gas. The measuring device comprises a measuring sensor arrangement which consists of: a capacitive sensor thermally coupled to a heating element and to a temperature sensor; an energy source connected to the heating element; a first evaluation circuit connected to the temperature sensor. The heating element and the temperature sensor are formed by a common temperature-dependent resistor. Together with the temperature dependent resistor and the energy source, the second evaluation circuit forms a control circuit for keeping the temperature of the capacitive sensor constant. As a function of the capacity of the capacitive sensor as the sole variable the first evaluation circuit determines the actual value of the relative humidity of the gas from previously determined calibrating values at the same constant temperature by interpolation or extrapolation of the calibrating values.