Measurements of Lower Humidities over Saturated Aqueous Salt Solutions

Abstract

Relative humidities lower than about fifty percent were measured by use of saturated aqueous solutions of certain inorganic salts in the range of 10° to 50°C. In some cases, a hydrate salt existing in solid phase converts to a lower hydrate salt at a given temperature. Discontinuous changes of relative humidity were shown near this transition point. Furthermore, it was found that there was a very small difference of relative humidities between pure and impure salts. We concluded that pure salt was not necessary for humidity control only, but that cheaper impure salt was enough. © 1983, The Society of Chemical Engineers, Japan. All rights reserved.