Microwave Dryer include:
- Drying food products using microwaves,
- Atmospheric and vacuum drum dryers other special designs, e.g. flow heaters, etc,
- Microwave dryers: chamber dryers operating at atmospheric pressure,
- Fluidized and pulso-fluid dryers, belt dryers,
Types of Microwave Dryers:
Microwave chamber dryers are very rarely used on an industrial scale due to uneven heating of the dried material. This effect is eliminated by movement (rotation) within the chamber inside the chamber. An example is commercial microwave ovens with a rotating plate on which the material to be heated (dried) is placed.
In order to minimize the effect of the formation of a non-uniform field inside the chamber, systems equipped with a large number of low-power microwave generators or with generators operating in the lower frequency range (30 MHz – 300 MHz) are used.
Fluid bed dryers with microwave heating
The dried material floating in the air stream is heated with microwaves introduced into the drying chamber from several microwave generators.
Dryer designed for the so-called final drying. The material can be dried by conventional method until it reaches a moisture content of about 20-25% – and is then dried in a microwave vacuum oven. The dryer is made on the basis of a typical meat tumbler, powered by microwave generators with a power of 6kW (f-2450 MHz).
Low pressure microwave dryer
Used for drying vegetables and fruits from the so-called the effect of “puffing” (explosion puffing is a processing system which facilitates hot air drying of fruits and vegetables. Explosion puffed foods are easily rehydrated and have excellent sensory properties. The process costs are similar to the cost of conventional hot air drying.)