Vegetables drying is the use of heat pump heating, adopt the method of hot air circulation, that is to say the air as a carrier, with the hot air to the material surface to make material heat sweating, and then take away the moisture, repetition, the materials and meet the requirements for the purpose, to master the three stages in the actual operation, heating stage, constant speed stage of drying, slow drying stage.



1.The initial stage heating

First of all, the temperature is set to 43-48℃, and the humidity is kept at 53℃ for 1-2 hours. It makes the water on the surface of vegetables absorb energy and turn into water vapor, and then a large amount of water evaporates out.
When the hot gas flow rate is faster, the temperature is lower, and the relative humidity of the drying room is smaller, and the moisture content decreases, and the drying speed is accelerated.

2. Constant speed drying stage

The speed of evaporation of water in vegetables depends not entirely on the temperature of the dry air, but on the humidity of the air. The lower the relative humidity, the faster the water will migrate and evaporate.

3.Eceleration drying stage

When vegetables evaporation rate of 50-60%, free water greatly reduced, when the vegetables internal moisture diffusion speed slow down, the surface water evaporation is slow, said vegetables deceleration phase, this phase with the evaporation of moisture, the temperature of the drying room also gradually rise, the water content reaches an equilibrium moisture content,
The moisture content of the material is about 15%, the drying time is 8-15 hours, the drying is completed, and the high quality drying effect is achieved at this time.