Abstract
A precision humidity generator was manufactured in order to establish the humidity standard. This generator can make air of constant humidity from about 10 to 100% relative humidity and with an accuracy of 0.2%.
The paper describes the principle of generation, the structure of instrument, the process of handling, the temperature and the humidity stability and uniformity in the test chamber and so on. The principal features of the generator are given as follows; (1) The two-pressure and the two-temperature methods are used at the same time to extend the humidity range. (2) The pre-saturator is added to complete the saturation and to stabilize the temperature. (3) The test chamber is immersed in the thermostatic water bath whose temperature is controlled within 10mK.
(4) The measurement of pressure and temperature and the calculation of humidity are automatized.
