Operating principle of constant temperature and humidity equipment

Constant temperature and humidity equipmentThe operating principle

The operation of the constant humidity and humidity machine system is through three interconnected systems: refrigerant circulation system, air circulation cycle, electrical automation systems;

Refrigerant circulatory system

The liquid refrigerant in the evaporator absorbs the heat of the air (air is cooled and dehumidification) and begins to evaporate, eventually forming a certain temperature difference between the refrigerant and the air, the liquid refrigerant is completely evaporated into a gaseous country, then inhaled and compressed by the compressor (pressure and temperature increase), the gaseous refrigerant absorbs heat through the condenser (air cooling/water cooling), Condensed into a liquid. Through the expansion valve (or capillary) throttling into a low-temperature low-pressure refrigerant into the evaporator, complete the refrigerant cycle process.
Air ring System

The fan is responsible for inhaling air from the back vent, air through the evaporator (cooling, dehumidification), humidifier, electric heater (heating) After the air vent sent to the user's space, sent out of the space and the air in the room mixed back to the back vent.

Electrical automation system

Includes the power supply part and the automatic control part. The power supply part through the contactor, the compressor, fan, electric additive, humidifier and other supply of automatic control parts are divided into temperature, humidity control and fault protection part: temperature, humidity control is through the temperature, humidity controller, the air temperature of the air is compared with the temperature and humidity set by the user, automatic operation of the compressor (cooling, dehumidification), humidifier, Electric heating (heating) and other components to achieve constant temperature and humidity automatic control.


Tectonic features
In the box structure, constant temperature and humidity test box is the use of CNC machine tool processing molding, elegant shape, novel, and the use of non-reaction handle, easy to operate. Studio using imported mirror board advanced stainless steel made, box outside the tank using A3 steel plate spray molding. The outside of the box and the inner gall filled with ultra-fine insulation cotton, temperature insulation effect is very good, effectively reduce the temperature fluctuation rate in the test box, and then with anti-aging silicone rubber sealing strip of the strict seal, so that the box without fog leakage phenomenon. Due to the harsh environment in the test box, in order to observe the situation in the Clear test box, Wuhan is still measured in the observation window is the choice of multi-layer tempered glass production, and in the observation window set up a separate lighting and fog brush, maintain a good view of the observation, at any time to monitor the test situation. Of course, in order to collect test data, the box is specially equipped with a 50mm diameter test hole, can be connected to the recorder, printer and computer.
Control features

The control system of the test box can be said to be the heart of the whole equipment, in charge of refrigeration, heating, moisture control, circulation, control and other power.
In refrigeration, compressors are compressors imported from Germany. The refrigeration system consists of high temperature part and low temperature part, each part is a relatively independent refrigeration system. The evaporation of refrigerants in the high temperature part is vaporized by the heat of the refrigerant from the low temperature part, while the evaporation of the cryogenic part of the refrigerant absorbs heat from the cooled object (the air in the test machine) to obtain the cold quantity. Between the high temperature part and the low temperature part is connected with a evaporation condenser, which is not only the condenser of the high temperature part, but also the condenser of the low temperature part.
The heating system adopts completely independent nickel chromium alloy electric heating type, the resistivity is large, the resistance temperature coefficient is small, the deformation is small at high temperature and not easy to brittle, the heating temperature can reach 1000~1500℃ and the service life is long.
Humidification is a constant temperature and humidity test box is different from the most important part of the high and low temperature test box, constant temperature and humidity test box using external isolation type, all stainless steel boiler type shallow surface evaporation humidifier. Dehumidification method using mechanical refrigeration dehumidification, air cooling to the dew point temperature below, so that more than the saturated moisture content of water vapor condensation precipitation, thus reducing the humidity.
Ventilation circulation System: Air circulation system by temperature-resistant low-noise air-conditioning motor, multi-leaf centrifugal wind wheel composition. It provides a cycle of air in the test machine.
The control system is the core of the comprehensive test box, which determines the heating rate, precision and other important indexes of the test machine. Most of the controller of the test machine adopts PID control, and there are also a few parts that use the control mode of PID and fuzzy control phase combination. Because the control system basically belongs to the scope of the software, and this part in the use of the process, generally do not appear problems.