Studies on respiratory humidity I. A photo tube dew-point hygrometer for measuring humidity of resqiratory gases

A photo tube dew-point hygrometer is used for measuring humidity of respiratory gases, which are in varying conditions. It makes it possible to make an accurate, precise, continuous and recording of the dew point of gas flows. The most notable features of this device are: (1) Simplicity of calculating absolute humidity, since the humidity is indicated with dew point. (2) Calibration is easy and reliable. (3) Performance is stable, and its operation and maintenance are simple. (4) Indication is correct and unaffected by temperature. (5) There is good response to any quick changes in humidity. (6) There is continuous and recording of humidity, especially with simultaneous temperature measurements on the same paper. (7) Impurities such as the vapors of organic substances or volatile agents do not affect the performance. Simple wiping can eliminate the disturbance from mirror contamination. (8) The entire apparatus is on a cart and easily movable. This device provides a new method of studying the functional relationship between humidity and various respiratory states, and it is hoped it will contribute much to physiological and clinical investigations. The principle and structure of the automatic D.P. hygrometer, the apparatus and method for practical hygrometry and obtained results are described and discussed.