Block Diagram of Dielectric Heating

Block Diagram of Dielectric Heating

• The block diagram of dielectric heating as shown in Figure consists of RF source, electrodes and timer.
• RF source is generating high frequency output using tank circuit. The frequency of application is obtained by tuning of tank circuit.
• The electrodes are provided with the output from tank circuit. The job to be heated is kept between the electrodes. So the distance between the electrodes is changed according to the application. Timer is used to control the heating process either with feedback or without feedback.

• The power loss taking place in a dielectric material is given by,

P_o = 0.55 x 10^-12f[V/b cm]² (loss
factors)

From Equation ( 5.6.2 ), we conclude that the power loss per unit volume (P_o) in a dielectric slab depends upon following factors :

1. It increases with increase in frequency of operation.
2. It increases with the square of voltage gradient, [V/b cm]² and
3. It depends upon the constants of the dielectric material through the loss factor, (€ _r tan 8).

Below Table gives the constants of some typical dielectric materials.