Dew-point meter is suitable for industrial applications, such as air drying equipment, plastic injection molding equipment, glove box drying equipment, lithium battery moisture detection, hydrogen, carbon dioxide, water, etc. The sensor chip is made from a kind of special material, the surface coverage, teflon layer, in a relatively long time resistance to chemicals and harmful substances, the product also has the function of automatic calibration, when the dew point is less than. . . 60 ℃ below the Td, will automatically start the self-calibration function, in order to ensure the accuracy of the product. Grain is a classical measurement principle. Let the test sample flows through a desiccant, and its moisture content * * dry agent absorption, weigh and desiccant absorption of moisture content, the ratio of gas volume is the sample with the sample gas humidity. The advantage of this method is of high precision, * * permissible error can reach 0. 1%; Defect is specific operation is difficult, especially must get enough amount of absorbed water quality ( Generally not be less than 0. 6 g) , this is especially difficult for low humidity gas, must increase the sample gas flow, the result will lead to measure time and increase error ( Measured humidity is not instantaneous value) 。 So this method is only suitable for measurement of dew point - 32 ℃ or more gas, purely using the method of humidity measurement instrument on the market. We can see in our daily life, the night air at lower temperature, the moisture in the air will be a part of precipitation, forming the dew or frost. This shows that under the condition of the water vapor content is constant, due to the lower temperature, can make originally not saturated with water vapor in the air can become saturated vapor, excess water will precipitate. Make the temperature at which the water vapor saturated is called the dew point. The dew point temperature have been measured, you can in the table of saturated water vapor to check the water vapor content. Due to lower temperature in the process of water vapor content does not change as a result, determination of dew point is actually measured the moisture in the air. If a lower dew point, said the less moisture in the air. Dew point can be used for the dew-point meter measurement. For example, the air dew point for - after the dryer 50 ℃, and - 50 corresponding saturated water content (38 ℃. 89 mg/m3, still contain the moisture in the air. If the dew point is - 60 ℃, the saturated moisture content of 10. 68mg/m3。 Dew point is lower, the higher the degree of dry.