In laboratories, constant temperature humidity test chamber are used extensively due to their exceptional performance and high level of intelligence, which makes them very popular among users. The structure of these chambers is relatively complex, as they are controlled by sophisticated systems. Their excellent cooling control is one of the reasons for their popularity.
When the temperature of the chamber reaches the set value, temperature sensors in the freezer and small refrigeration chamber detect this and their resistance decreases. This change is converted into a voltage signal by the signal conversion circuit on the main control board and sent to the CPU.
The CPU then processes this information and outputs a cooling control signal to activate the relay, which connects the compressor to the power supply circuit. The compressor starts operating, initiating the cooling process. At the same time, the CPU outputs a solenoid valve control signal to close the valve leading to the freezer’s capillary tube while opening the valve to the refrigeration chamber’s capillary tube. This allows the refrigerant to flow through the evaporators in both the refrigeration and freezer compartments, cooling them down.
As the compressor continues to run, the temperatures in the refrigeration and freezer compartments begin to drop. Once the refrigeration chamber reaches the set temperature, the resistance of its temperature sensor increases. The CPU detects this and outputs a solenoid valve control signal to close the valve leading to the refrigeration chamber’s capillary tube while opening the valve to the freezer’s capillary tube.
At this point, the refrigerant flows only through the freezer’s evaporator, continuing to cool the freezer compartment. When the freezer reaches the desired temperature, the resistance of its temperature sensor increases. The CPU then processes this and outputs a stop signal to the relay, cutting off the power supply to the compressor. The compressor stops, and the cooling process ends.
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