In the late 1980s, China began to develop microwave vacuum drying equipment, through years of efforts, to around 2000, the successful solution of the low-pressure microwave field arc discharge, heating temperature difference between the shop floor, the microwave non-contact temperature measurement A number of problems, from the experimental stage into the industrial production stage. For food engineering, pharmaceutical engineering, biological engineering, chemical engineering, materials engineering and agricultural and sideline products deep processing provides a new, efficient drying equipment.

Microwave vacuum drying characteristics:

Efficient: conventional vacuum drying equipment, (assuming the vacuum pressure of 7.37kpa, the material dehydration temperature of 40 ℃, 1kg of water vaporization heat is 574 kcal), due to the vacuum situation, heat convection is very difficult, only conduction , The heating rate is slow, long drying cycle, energy consumption. Microwave vacuum drying equipment uses a radiation energy transfer, the overall heating medium, without other heat transfer medium, to avoid the above shortcomings, so fast, high efficiency, greatly reducing the drying cycle, energy consumption. Compared with the conventional drying technology can improve work efficiency more than four times.

Heating evenly: As the microwave heating is inside and outside the material at the same time heating, the temperature inside and outside the material is small, does not produce conventional heating in the inconsistency of the situation inside and outside, leaving the dry quality greatly improved. Easy to control: to facilitate continuous production and automation, microwave power can be quickly adjusted and no inertia characteristics, easy to timely control, easy to adjust and determine the process parameters.

Equipment, small size, easy installation and maintenance:
In this case,
Product quality: Compared with conventional methods, the processing of the product quality has greatly improved.

In addition microwave equipment with disinfection, sterilization effect, product safety and health. Shelf life can be extended.

From the above features, energy saving, reduce consumption, improve product quality, safety and health, equipment, low investment costs can be seen in various aspects of its economic and social benefits significantly. In the dehydrated vegetables processing, to each kind of drying equipment technological performance, the economic efficiency, the product quality and so on the comparison result like table.