Hair hygrometer

Haas, D. B. 203, 204, 228 Hagen, G. 78, 139 Hair hygrometer 759 Hairpin tubes, heat exchanger 505 --------exchangers 503... 

Sensors for Measuring % RH. Over the years, devices other than the simple hair hygrometer have evolved which permit a direct measurement of i RH. These devices are. Inr the most part, electrochemical sensors that offer a degree of ruggedness, compactness, and remote electronic readout ability not afforded hy hair devices. 

Descriptive of a substance, the physical characteristics of which arc appreciably altered by effects of water vapor. The hygroscopicity of certain materials has been advantageously utilized ill humidity measurement and control devices for example, the hair clement of a hair hygrometer. 

Samples of the pure cellulose have been conditioned at relative humidities of 10, 20, 40, 60 and 80% at a temperature of 25 1°C. The conditioning process has been carried out in desiccators in which the cellulose samples were spread out over saturated aqueous solutions of the proper concentrations. The relative humidity was measured in each desiccator by a hair hygrometer calibrated against... 

In order to determine relative air humidity in the testing chamber, most often hair hygrometers are used. Air humidity is measured indirectly through the change in length of a hair bundle. 

Mechanical Hygrometers Materials such as human hair, wood fiber, and plastics have been used to measure humidity. These methods rely on a change in dimension with humidity. 

Mechanical hygrometer is based on animal or human hair whose length increases when the relative humidity increases and contracts when it decreases. The change in length actuates a lever, which turns the pointer on a dial. This is not a very accurate device however. 

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