Measurement of moisture content per unit volume in air on hygrometer - is by raising temperature to predetermined value and recording relative humidity

摘要

The system is for determing the moisture in air as a volume percentage. The air is raised to a preset temperature and then the relative humidity at this level measured. The raising of the air temperature is effected by resistance heating elements. These are controlled via a feedback loop with the controlling signal derived from a thermistor sensing element (6) fitted downstream of the resistance elements (4). The air to be measured is passed over a conventional hygrometer (9) which emits a signal along a calbe (13). If a particular relative humidity is desired, then moisture could be added to the air on the basis of the readings obtained.