High-Frequency Heating and Its Applications

In the meat industry, meat processing can be done using different methods like hot water & conventional steam treatments. But these two are conductive heating treatments as they depend on the conduction of heat from the inside as well as outside of the meat. Consequently, this requires more time for treatment otherwise there will be undesirable transformations that will occur within the quality of meat. To overcome this problem, a method like High-frequency heating is used for eliminating microorganisms. This article discusses an overview of High-Frequency Heating.

What is High-Frequency Heating?

High-frequency heating is also named radiofrequency/dielectric heating, microwave & IR heating. This is a thermal method, used for eliminating microorganisms. This heating method utilizes electromagnetic energy to warmth the products. This offers an additional fast & consistent heat supply and also reduces the quality drop of the products. This is an alternative method for hot water as well as conventional steam treatments in meat processing.

Working Principle

The material which we want to heat is located like a piece among two metallic electrodes where high-frequency voltage is applied so that a sufficient amount of heating, as well as enough loss, will be provided. The frequency range used in this heating ranges from 10 MHz to 20 MHz. The range of voltage changes from 10 – 20 kV. The required high-frequency voltage supply can be obtained using a valve oscillator.

When an AC voltage supply is given across its two plates then the flow of current will be drawn through the capacitor, which doesn’t direct the voltage supply exactly by 90°.  It means that there is a certain current component which is in phase through the voltage. Because of this current component, heat can be generated within the dielectric material.

Here the dielectric loss can be defined as the electric energy which is dissipated in heat energy from within the dielectric material. This loss is directly proportional to V2f so high-frequency voltage can be utilized in dielectric heating. Generally, 20 kV of ac voltage at 10-30 MHz frequency is used. Dielectric heating is used for paper, textiles drying, plywood manufacture, etc. In the case of dielectric heating, the overall efficiency is about 50%.

Advantages

The advantages of high-frequency heating include the following.

• Dielectric heating is appropriate for non-conducting materials such as plastic, wood, and synthetic compounds.
• When the heat is generated during the complete mass of material, then we get consistent heating. By using a conventional heating method, it is not achievable to get this.
• To complete this process very little time is necessary when contrasted to another method.

Disadvantages

The disadvantages of high-frequency heating include the following.

• This method is suitable for the highest dielectric loss materials
• The dielectric heating overall efficiency will be very low
• The radio interface can be caused due to high frequencies.
• The equipment used for dielectric heating is so costly so it is used only where other techniques are unfeasible.

High-Frequency Heating Applications

The applications of this heating include the following.

• There are many industries that use dielectric heating techniques like paper, textiles, food, chemicals, and plastic.
• There are many applications like baking, drying, welding, polymerization and defrosting.
• These come under the techniques of dielectric heating or high frequency.
• These two are electromagnetic wave energy forms.

Thus, this is all about high-frequency heating or dielectric heating which can be used in drying paper, tobacco, wood, etc. Here is a question for you, what are the alternate names of high-frequency heating?