Thermal shock test chamber in order to achieve the test condition inevitably humidification and dehumidification of the test box operation, this paper intends to present in humid Chamber analysis widely used in a variety of methods, pointing out the advantages and disadvantages of each, and recommended conditions of use.
Many methods of humidity, test equipment, are usually described using the concept of relative humidity and humidity. Relative humidity is defined as the air in the water vapor partial pressure and the ratio of saturated vapor pressure of water at the temperatures and expressed as a percentage. By the saturation pressure of water vapor, water vapor saturation pressure is a function of temperature, is independent of air pressure and water vapor, through a large number of experiments andorganize to seek to represent the relationships between the water vapor saturation pressure and temperature, which has been used by engineering and measurement should be the gefugelieqi formula. It is current meteorological departments toproduce humidity tables used.
Hot and cold shock testing machine humidification process is to increase the partial pressure of water vapor, originally of humidification is to spray water Chamberwall, saturation pressure is controlled by controlling the temperature of the watersurface. Wall surface water to form larger surfaces, on this surface by diffusion into the box to join the vapor pressure inside the box in the form of increased humidity in the Chamber, this approach appears in the 50 's of last century. Due to at on humidity of control main is with mercury electric contact type conductive table for simple of switch volume regulation, for big lag of hot box water temperature of control adaptability poor, so control of transition process more long, cannot meet make variable hot and humid on added wet volume requirements more of need, more important to is in on box wall spray got of when, inevitable to has drops got in try products Shang on try products formed different degree of pollution. While the tank drain is also have certain requirements. Therefore we used in the earlier steam humidification and shallow-water humidification, although it control process is longer, but the system stabilizes climate fluctuation, more suitable for damp heat, steady state testing. Water vapor without overheating in the humidification processdoes not add extra calories in your system. Also, when control of spraying water temperature to below the test requirements of temperature, water spray has a dehumidifying effect.