Electrically Aspirated Thermometer by Frankenberger

Electrically aspirated thermometer by Frankenberger for continuous measurement of the air temperature with high accuracy; double protection against global and reflex radiation.

The chrome-plated tubes are insulated against the shaft and against each other by plastic rings.

This instrument in its present design was developed by Frankenberger and provides continuous measurement of the air temperature with high accuracy. The design of the instrument essentially eliminates the effects of wind and radiation. Outdoor measurement, even at high altitudes -e.g. for detection of inversion layers- is possible.

Operating principle:

Inside the downward inclined radiation shield tube a platinum resistance thermometer is mounted. This sensor is a hard glass encased Pt 100 Ω resistance in accordance with DIN 60751 B, 1/3 tolerance (resistance = 100 Ω at 0°C), which resistance changes with the temperature according to a typical characteristic line. The sensor can be connected by means of a 3-wire or 4-wire supply system.

This way measurement over long distance can be carried out without the line resistance falsifying the result. The resistance thermometer is continuously aspirated by a ventilating system providing an air flow of about 3.5 m/s.