After entering the curing barn, braided tobacco leaves undergo five stages: 1. Low-temperature humidity control for yellowing; 2. Stable temperature for moisture removal and post-ripening; 3. Ventilation for dehydration and drying; 4. Temperature and humidity control for drying the stems. Each stage has different temperature and humidity requirements.

The tobacco curing process is extremely delicate; even the slightest mistake can ruin a whole room of tobacco leaves. Using an air-source heat pump tobacco dryer, the temperature and humidity in the curing barn can be controlled.

The initial stage of tobacco leaf drying is the color change stage, which softens the leaves. The temperature must be kept below 38°C and the humidity above 90%.

During the early color fixation stage, the temperature rises slowly to below 42°C and the humidity is kept above 60%.

After the color fixation stage, the temperature slowly rises to 54°C and the humidity is kept at 40%.

During the stem drying stage, the temperature is rapidly raised to 68°C, and continuous rapid dehumidification is performed, ultimately completing the process when the tobacco leaves reach a humidity of 8%.

If hard and yellowing tobacco leaves are observed, ventilation and heat removal should be increased during this period to help the tobacco leaves soften and collapse. The sooner hard and yellowing are corrected, the less impact on tobacco quality; the later the correction, the greater the impact. Using an air-source heat pump to dry tobacco leaves offers high thermal efficiency. Combined with hot air circulation, this system not only achieves high thermal efficiency but also maintains uniform temperature and humidity within the tobacco loading chamber, allowing for smooth ventilation and dehumidification. This promotes more complete yellowing of the tobacco leaves before color setting, improving their quality.

Guoxin Machinery's air-source heat pump tobacco dryer utilizes a PLC microcomputer control system, enabling precise computer control of the drying room temperature. It also features automatic humidity monitoring. When the humidity exceeds a certain value, a dehumidification fan removes moisture to maintain optimal drying results, eliminating customer concerns.