
SAFE MICROWAVES

Despite centuries of exploration, we have barely grasped the potential uses of magnetism. All interactions with our surroundings are impacted by the natural magnetic forces of objects and by electromagnetic fields from various devices. Advances in sensors and instrumentation technologies are helping to better utilize the power of magnetism. Magnetic energy is present in all objects from the largest, like the magnetic field around our planet earth, to the magnetic field in the smallest atomic and subatomic particles in everything else. We are still learning how to fully utilize the energy of electromagnetic fields and the interactions with the natural magnetic and static electric fields of matter. The concept becomes a bit more fascinating when electricity and magnetism interact.
QUICK FACTS ABOUT MICROWAVES
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First introduced in the 1960s, microwaves are used universally in homes and restaurants.
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A household microwave has a wave transmitter called a “magnetron” that generates microwaves and is attached to a duct called a “waveguide” that sends the waves into the cavity or cooking area of the microwave unit.
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WAVEtek’s microwave process is a new variation of the home microwave cubical chamber where products are heated or cooked.
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By designing a vessel that can work with microwaves, WAVEtek technology uses a vertical cooking pot or vessel to heat products.
Figure 1a depicts a cup of milk cooking in a household microwave, and
Figure 1b depicts milk warming on a stovetop; needing stirring due to “hotspots.”

(1a) Cup of milk in microwave

(1b) A cup of milk on stove Stirring Required
SAFE MICROWAVES
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We refer to the microwave generator as a “transmitter” because, like a radio or television signal transmitter, the waves can be transmitted through air, waveguide, or coaxial cable.
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Microwaves frequency is below the visible light, in principle making it safer than sunlight. It is also non-ionizing, compared to x-ray or gamma rays that are ionizing and dangerous.
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WAVEtek uses larger more powerful microwave transmitters ranging from 6 kW to 100 kW and a longer waveguide to send the wave into a cooking chamber. Figure 2 shows a conceptual illustration of the WAVEtek Plug and Heat™ Lab-Scale system that includes:
​a. A 6kW microwave transmitter,
b. A chiller to cool the microwave,
c. Solid or flexible waveguides,
d. Cooking or heating vessel with a temperature sensor,
e. Circulation pump to mix the product while heating,
f. A control panel to allow the user to select how much power to apply (how fast to heat) and at what temperature to heat the product to.

Figure 2
SAFETY AND ACCURACY OF HEATING
In conventional steam heat systems, the heating of product must be slowed down before the desired temperature is reached or overheating can take place. Slowing the heating too much will slow down the process and not soon enough could cause overheating or the need for heat exchangers to cool the heating medium. In the WAVEtek process, we program the microwave controller to monitor the product temperature and, once it is within one degree of the desired temperature, it ramps down the microwave input from the set kilowatt to zero or near zero. This process continues and microwave input is continuously adjusted up or down to stabilize the temperature at the desired temperature (+/- 1 degree). This results in accurate heating each time without over or under heating.
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In conventional heat transfer oil or steam systems, even if the source steam or heat transfer oil are shut off for an emergency, the latent heat in the jackets of the vessel will continue to heat the product. In the case of chemical processes, a runaway reaction such as “foaming” cannot be stopped. With microwaves, once the stop button is pressed, all energy input stops completely reducing the chances of over-running the reaction, boil overs, or excess foaming that happens in some processes.
INEFFICIENCY IN CONVENTIONAL SYSTEMS
For large scale heating or cooking, steam from a boiler is applied to the jacket or outside layer of a jacketed vessel. This means some form of chemical energy, typically natural gas or propane, is burned or converted to thermal energy (one energy conversion step); then the heat of the burning gas is applied to water to change phase and generate steam (thermal energy to thermal energy conversion – a second step); steam is sent into the jacket of the vessel to heat the walls of the cooking vessel (another thermal to thermal “conduction” energy conversion) - making a third energy conversion. Each energy conversion step has losses that will accumulate. Additionally, the jacketed tank and the steam pipes require insulation and even with insulation added, there will be some heat loss or waste of energy.
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Since the walls of the cooking vessel are hot, some form of surface scraping mechanism will be needed that typically includes a gear box and an electric motor to operate and scrape the walls and agitate the product. This adds one more system (mechanical) that has its own losses and inefficiencies.
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The cost of including a jacket system, special certified welding required, and the inclusion of a drive motor, gear box, and scraping arms adds to the overall cost of the equipment and is yet another source of inefficiency.

EFFICIENCY IN WAVE-BASED HEATING SYSTEMS
WAVEtek systems do not require steam, or jacketed vessels, or scrape surface mixers and drive mechanisms. Waves are delivered to the product from the top or side of the vessel and the product itself is heated. This means, when product molecules are showered with magnetic and electric forces of the waves they try to align themselves with the magnetic lines and the electric charges of the waves, millions of times a second, they bump into each other creating frictional heat.
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In conventional heating systems the heating medium within the jacket of the vessel is normally at higher temperatures than the desired product temperature. This requires scraping the walls of the vessel because the walls of the vessels are much hotter, and the product would burn if not scraped clean. Products that are exposed to the hot walls of the vessel will often burn in microlayers as evidenced by the change in color. With microwave heating, because the product is not exposed to hot surfaces, there are no hot spots to burn or discolor the product. As a result, products processed with waves are cooked more uniformly and have lighter colors.