研究控制湿度的方法,国外已有五十多年的历史.1921年,WiLson等应用硫酸溶液控制气体湿度,1924年,DunlaP用盐溶液可作为湿度控制剂.此后,很多学者相继研究不同浓度硫酸溶液,各种盐溶液以及混合盐溶液控制气体相对湿度,发表了许多有关控制湿度的论文报告,指出在恒温条件下,一定浓度的盐溶液与水气压相平衡,保持一定相对湿度的气体. The method of controlling humidity has been abroad for more than fifty years. In 1921, WiLson et al. Used sulfuric acid solution to control the gas humidity, and DunlaP used salt solution as a humidity control agent in 1924. Since then, many scholars have studied the effect of different concentrations of sulfuric acid Solution, various salt solution and mixed salt solution to control the relative humidity of the gas, published many papers on the control of humidity, pointed out that under constant temperature conditions, a certain concentration of salt solution and water vapor pressure phase equilibrium to maintain a certain relative humidity of the gas.