Humidification and dehumidification of the hottest

2022-10-01
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Humidification and dehumidification of cold and heat shock test chamber

the cold and heat shock test chamber can simulate the instantaneous changing environment between high temperature and low temperature. So as to judge the reliability of the product. After the end of the experiment, you can check whether the appearance and stability parameters are qualified. It will provide you with the basis for predicting and improving the quality and reliability of products. The cold and heat shock test chamber is used to test the resistance of electronic, automotive, rubber, plastic, aerospace technology and advanced communication equipment under repeated cold and heat changes

in order to realize the test conditions, the cold and heat shock test chamber inevitably needs to humidify and dehumidify the test chamber. This paper intends to analyze a large number of methods that are widely used in the damp and heat test chamber at present, and point out their respective advantages and disadvantages and the conditions that are recommended to be used

There are many ways to express humidity. For test equipment, the concept of relative humidity is usually used to describe humidity. The definition of relative humidity refers to the ratio of the partial pressure of water vapor in the air to the saturated vapor pressure of water at this temperature, which is expressed as a percentage. From the properties of water vapor saturation pressure, it can be seen that the saturation pressure of water vapor is only a function of temperature, and has nothing to do with the air pressure where water vapor can be located. People have sought to express the relationship between water vapor saturation pressure and temperature through a large number of experiments and collation, among which the formula that has been widely used in engineering and Metrology should be govglidge's formula. It is used by the meteorological department to compile the humidity check table at present

the humidification process of the cold and hot shock test chamber is actually to increase the partial pressure of water vapor. The initial humidification method is to spray water on the wall of the test chamber, and the saturation pressure on the water surface is controlled by controlling the water temperature. The water on the surface of the chamber wall forms a large surface, on which water vapor pressure is added to the chamber by diffusion to increase the relative humidity in the test chamber. This method appeared in the 1950s. At that time, the humidity control was mainly based on the simple on-off value adjustment of the mercury electric contact conductivity meter, which was not adaptable to the control of the water temperature of the hot water tank with a large lag. Therefore, the transition process of the control was long, which could not meet the needs of alternating damp heat for more humidification. More importantly, when spraying the tank wall, it was inevitable that water dripping on the test object would form varying degrees of pollution to the test object. At the same time, there are certain requirements for the drainage in the box. Therefore, we used steam humidification and shallow water dish humidification in the early stage. Although its control transition process is long, the humidity fluctuation is small after the system is stable, which is more suitable for constant damp heat test. In addition, during the humidification process, 6. Before loading, check whether the loading handle is placed in the unloading position, and the water vapor is not overheated, which will not increase the additional heat in the system. In addition, when the spray water temperature is controlled to be lower than the key temperature required by the test, the spray water has a dehumidification effect

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