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HOW INDUSTRIAL MICROWAVES HEAT
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MICRODRY INCORPORATED
5901 W. HIGHWAY 22
CRESTWOOD, KY. 40014
(502) 241-8933 PH
(502) 241-5907 FAX
engineering@microdry.com

Microdry

 Fig 1: Microwave FrequencyWhen microwave heating can be used - and is used properly - almost certainly you will process more product in less time at lower cost. Throughout history there has been one way to heat materials: apply heat to its surface. About thirty years ago, industrial engineers began developing microwave heating techniques that avoid some limitations of conventional heating.

Fig 2: Molecular ActionWith microwaves, no heat is applied per se. Instead a form of radio waves (not nuclear nor ionizing radiation (see Fig.1) pass through the material. The molecules in the material then act like miniature magnets attempting to align themselves with the electrical field. Under the influence of this high frequency alternating electrical field, the particles oscillate about their axes creating intermolecular friction which manifests itself as heat (see Fig. 2)Fig. 3: Conventional Heating

What are the advantages...
In conventional heating the heat source causes the molecules to react from the surface toward the center (see Fig. 3) so that successive layers of molecules heat in turn. The product surfaces may be in danger of over heating by the time heat penetrates the material. Microwaves, however, produce a volume heating effect. All molecules are set in action at the same time (see Fig. 4). It also evens temperature gradients and offers other important benefits.

Fig 4: Microwave HeatingExamples...
A producer of fat-free potato chips was awarded a patent using a microwave system designed by Microdry making it possible to produce a potato chip with the characteristics of a fried chip without the use of oil.

The pre-drying stage of ceramic filters used in smelting processes can be cut from hours to minutes due to the ability of the microwave energy to penetrate the material and force the moisture to the surface greatly reducing time and energy consumption since the ovens operate at nearly 80% efficiency.

A manufacturer of building supplies replaced costly, less efficient equipment with Microdrys' microwave equipment giving them a clear competitive edge over their competitors while also allowing them to use less costly raw materials and reduce the cutting of forests as well.

How does an industrial microwave system differ from a home microwave oven...
The home/restaurant batch-type ovens available to date employ a relatively low power source as compared to the industrial power source. This makes producing products beyond pilot scale levels very labor intensive. In addition, the typical home oven is considerably less efficient, up to 25% less, in converting electrical energy into microwave energy. By comparison the industrial oven can be designed as either a batch or as a continuous system with much higher power and greatly increased throughputs, reducing the amount of handling required. In addition, a forced air system can also be employed, which greatly improves moisture removal in drying applications.

  • The system employs a high energy power source with long life.
  • The system has a unique internal protection feature (patented) that traps stray microwaves, thus making the system completely safe to operate. A new exclusive type of forced-air system used in conjunction with microwave energy (patented) accelerates the removal of moisture quickly and efficiently.
  • A straight-through conveyor assures uniform exposure to the microwaves.
  • Because of its high processing capacity, unit costs are much lower than with the batch proces

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