[A simple climatic chamber for testing air filters 2. Communication: adjustment of relative humidity (author's transl)].

A climatic chamber for laboratory use is constructed using unexpensive materials. The relative humidity is to be adjusted between 20% and nearly 100% by regulation of the water temperature in the humidifier. The temperature range is 20-40 degrees C. As there are to be done experiments with air filter samples under practical conditions the system is enabled to work up 75 m3 of fresh air per hour. In comparison to commercially available apparatus the system described may be easily modified to fit the geometrical and experimental conditions.