Dew point mirror hygrometer - has cooling element, consisting of Peltier battery for reducing temp. of metal mirror and thermometer

摘要

A source of heat radiation is provided, radiating a wavelength between 4.5 and 7.5 mu m, absorbed by water. One dew mirror is provided, which does not absorb this radiation. The intensity of heat radiation and the cooling power of the Peltier battery are so mutually adjusted, that a dew film produced on the mirror is evaporated by the radiation. The resulting mirror cooling produces a new dew film, so that the mirror automatically takes the dew point temperature.