Constant temperature and humidity test Chamber, also known as "programmable constant temperature and humidity test chamber FR-1204 constant temperature and humidity chamber", belongs to the same series as "high and low temperature alternating humidity and heat test chamber/GDS-100". It is a necessary test equipment in other fields to test and determine the parameters and performance of electrical, electronic and other products and materials after high temperature, low temperature, alternating humidity or constant temperature environment changes.
The constant temperature and humidity test chamber can be divided into "desktop" and "vertical". The main difference is that the temperature and humidity that can be achieved are different, and the resulting temperature will also be different. The vertical type can be used for low temperature and drying below normal temperature. , The desktop can only do the temperature and high humidity above room temperature.
The constant temperature and humidity test chamber consists of two parts: temperature regulation (heating, cooling) and humidification. Through the rotating fan installed on the top of the box, the air is discharged into the box to realize gas circulation and balance the temperature and humidity in the chamber. The data collected by the built-in temperature and humidity sensor in the chamber is transmitted to the temperature and humidity controller (micro Information processor) to edit and process, and issue temperature and humidity control instructions, which are completed by the air heating unit, the condenser tube and the heating and evaporation unit in the water tank.
The temperature adjustment of the constant temperature and humidity chamber is to collect data through the built-in temperature sensor in the chamber, adjust the temperature controller (micro information processor), and connect the air heating unit to increase the temperature or adjust the refrigeration solenoid valve to reduce the temperature inside the chamber, so as to reduce the temperature inside the chamber. to the temperature required for control. The humidity adjustment of the constant temperature and humidity chamber is to collect data through the built-in humidity sensor in the body, adjust the humidity controller (micro information processor), connect the heating element of the water tank, and evaporate the water in the water tank to increase the humidity in the box or adjust the refrigeration. Solenoid valve to achieve dehumidification to achieve the required humidity control.
The constant temperature and humidity chamber is equipped with multiple protection measures; the temperature system is equipped with an over-temperature protector under the condition that the maximum safe allowable temperature can be set, and the air heating element can be automatically powered off when the rotating fan stops; the humidification system can be adjusted according to the water level of the humidification tank The power supply is stopped when the temperature is lowered; the refrigeration system also stops working when the temperature of the box rises (over 40°C) or the humidity increases.
A constant-humidity incubator refers to a test chamber that can apply temperature and humidity stress at the same time. With the needs of the development of Chinese industrial products, in recent years, China has introduced a large number of test systems from abroad, which have played an important role in the development and finalization of Chinese industrial products. Many problems have occurred, and problems cannot be solved in time, which greatly prolongs the test period and affects the development of products. The reason for these phenomena is the lack of understanding of the working principle of the comprehensive test. To this end, we briefly expounded 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 box is composed of a refrigeration system, a heating system, a control system, a temperature system, an air circulation system, and a sensor system. The above systems belong to two major aspects: electrical and mechanical refrigeration.
Structural features
In terms of box structure, the constant temperature and humidity test box is processed and formed by CNC machine tools, which is beautiful and novel in appearance, and adopts non-reaction handles, which is easy to operate. The studio is made of imported high-grade stainless steel with mirror panel, and the outer tank of the box is sprayed with A3 steel plate. The ultra-fine thermal insulation cotton is filled between the outside of the box and the inner tank, which has a good temperature insulation effect and effectively reduces the temperature fluctuation rate in the test box. In addition, the anti-aging silicone rubber sealing strip is tightly sealed, so that the box has no fog leakage. produce. Due to the harsh environment in the test box, in order to observe the situation in the test box clearly, Wuhan Shangshi chooses multi-layer tempered glass for the observation window, and sets up separate lighting lamps and fog brushes in the observation window to maintain a good observation field. , monitor the test situation at any time. Of course, in order to collect test data, the box is specially equipped with a test hole with a diameter of 50mm, which can be connected to recorders, printers and computers.
Control Features
The control system of the test box can be said to be the heart of the entire equipment, in charge of cooling, heating, humidity control, circulation, and control.
In terms of refrigeration, the compressor is imported from Germany. The refrigeration system consists of a high temperature part and a low temperature part, each part is a relatively independent refrigeration system. The evaporation of the refrigerant in the high temperature part absorbs the heat of the refrigerant from the low temperature part and evaporates; the evaporation of the refrigerant in the low temperature part absorbs heat from the object to be cooled (the air in the test machine) to obtain the cooling capacity. The high temperature part and the low temperature part are connected by an evaporative condenser, which is both the condenser of the high temperature part and the condenser of the low temperature part.
The heating system adopts a completely independent nickel-chromium alloy electric heating type, with high resistivity, small resistance temperature coefficient, small deformation at high temperature and not easy to embrittle, its own heating temperature can reach 1000 ~ 1500 ℃, long service life.
Humidification is the most important part of the constant temperature and humidity test box which is different from the high and low temperature test box. The constant temperature and humidity test box adopts an external isolation type, all stainless steel boiler type shallow surface evaporative humidifier. The dehumidification method adopts mechanical refrigeration and dehumidification, which cools the air to below the dew point temperature, so that the water vapor greater than the saturated moisture content condenses and precipitates, thus reducing the humidity.
Air supply circulation system: The air circulation system consists of a temperature-resistant and low-noise air-conditioning motor and a multi-blade centrifugal wind wheel. It provides the circulation of air in the test machine.