Constant temperature and humidity chamber, also known as constant temperature and humidity test chamber, constant temperature and humidity test chamber, programmable humidity and heat alternating test chamber, constant temperature machine, is used to test the performance of materials in various environments, and the resistance to drying and humidity of various materials . It is suitable for quality inspection of products such as electronics, electrical appliances, mobile phones, communications, instruments, vehicles, plastic products, metals, food, chemicals, building materials, medical treatment, and aerospace.

　　A constant humidity chamber is a test chamber capable of simultaneously applying temperature and humidity stress. With the needs of China's industrial product development, in recent years, China has imported a large number of testing systems from abroad, which have played an important role in the development and finalization of Chinese industrial products. However, due to its complexity, many problems occurred in the operation of the test box, which could not be solved in time, greatly prolonging the test cycle and affecting product development. These behaviors occur because we don't understand how synthetic testing works. To this end, we briefly introduced the basic working principle of the test box, and introduced how to analyze and judge the failure of the comprehensive test box test equipment.

　　The constant temperature and humidity chamber is composed of refrigeration system, heating system, control system, temperature system, air circulation system and sensor system. The above systems are electrical and mechanical refrigeration systems.

　　In order to facilitate the heat dissipation and maintenance of the box, the place where this equipment is installed meets the following conditions:

　　1. The distance from the adjacent wall or object is 300mm.

　　2. In order to stabilize the function and performance of the laboratory, a place with a perennial temperature of 15-35°C and a relative humidity greater than 85% should be selected.

　　3. The ambient temperature at the installation site must not change rapidly.

　　4. It should be installed on a horizontal surface (the level should be confirmed on the ground with a spirit level during installation).

　　5. It should be installed in a place exposed to direct sunlight.

　　6. It should be installed in a well-ventilated place.

　　7. Keep away from flammable and explosive materials and high-temperature heat sources during installation.

　　8. Install in a place with little dust.

　　9. It should be installed as close to the power supply as possible.

　　The constant temperature and humidity chamber consists of temperature regulation (heating and cooling) and humidification. The rotating fan installed on the top of the box can discharge the air into the box to achieve air circulation and balance the temperature and humidity in the box. The data collected by the temperature and humidity sensor in the box will be transmitted to the temperature and humidity controller (micro information processor) for editing and processing, and a temperature and humidity adjustment command will be issued, which is jointly completed by the air heating unit, the condensation pipe and the heating and evaporation unit in the water tank .

　　The temperature adjustment of the constant temperature and humidity box is to collect data through the built-in temperature sensor in the box, adjust it through the temperature controller (micro information processor), connect the air heating unit to increase the temperature or adjust the cooling solenoid valve to reduce the temperature in the box, so that To achieve the desired temperature for control. The humidity adjustment of the constant temperature and humidity box is to collect data through the built-in humidity sensor, adjust it through the humidity controller (micro information processor), turn on the heating element of the water tank, and increase the humidity in the box by evaporating the water in the water tank or adjust the cooling electromagnetic Valve to achieve dehumidification effect, so as to achieve the desired humidity control.

　　The constant temperature and humidity box has multiple protection measures; in the case of setting a very high safe allowable temperature, the temperature system is equipped with an overheat protector. When the rotating fan stops, the air heating element can automatically cut off the power; the humidification system can be adjusted at the water level of the humidification box. Stop the power supply when it drops; when the temperature of the box rises (over 40°C) or the humidity increases, the refrigeration system will also stop working.