JPH0119353Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to uniform heating of foods by improving the distribution of high-frequency electric fields on the foods of a high-frequency heating device.

Structure of a conventional example and its problems FIG. 1 shows the structure of a conventional high-frequency heating device equipped with, for example, a general radio-wave stirring blade.

1 is a high-frequency oscillator, which supplies high-frequency electromagnetic waves into the heating chamber 3 via the waveguide 2; 4 is a radio stirring blade rotatably provided on the upper surface of the heating chamber; Rotationally driven by an electric motor. Food 6 placed in the heating chamber is oscillated by an oscillator 1, propagates through a waveguide 2, and is heated by high-frequency electromagnetic waves supplied from an excitation port 7 provided in the heating chamber. The high-frequency electric field distribution within the heating chamber is determined by the dimensions of the heating chamber and the method of coupling the heating chamber and the waveguide, as shown by the broken line in the figure. This is because the propagation characteristics of high-frequency electromagnetic waves change depending on the dimensions of the waveguide, and the resonance mode within the heating chamber changes depending on the dimensions of the heating chamber, which is a resonator for high-frequency electromagnetic waves. Therefore, as an example of a method for uniformly heating food within a predetermined mode within a heating chamber, the electric field distribution is changed by rotating a radio-wave stirring blade made of a conductive material in the heating chamber, thereby changing the heating state of the food. An averaging method is used. However, due to the shape and size of the food to be heated, and high-frequency dielectric loss, the electric field mode in the heating chamber changes in size as the heating chamber equivalently functions as a high-frequency resonator, and the electric field mode collapses. Furthermore, the portion of the food product close to the excitation port of the heating chamber is heated strongly, while other portions of the food are heated only by the reflected waves irradiated into the heating chamber from the excitation port, so that the degree of heating is weakened. As a result, it has been difficult to obtain a good heating condition regardless of the shape or amount of food.

Purpose of the invention The present invention aims to eliminate the above-mentioned conventional drawbacks, and aims to uniformly heat food regardless of its shape and quantity.

Structure of the invention In order to achieve the above object, the present invention has a structure in which excitation ports are provided on opposing walls of the heating chamber, and high-frequency electromagnetic waves excited by a single oscillation tube are supplied to the heating chamber in different directions. Uniform heating can be achieved by directly irradiating the area with current.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

In FIG. 2, 8 is a high frequency oscillator and 9 is a heating chamber. High-frequency electromagnetic wave excitation ports 10 and 10' are provided near the center of the upper and lower surfaces of the heating chamber 9. A waveguide 11 guides high-frequency electromagnetic waves to the heating chamber 9 by communicating the high-frequency oscillator 8 with the excitation ports 10 and 10'. Further, the traveling direction of electromagnetic waves in the waveguide in the TE ₀₁ mode is indicated by arrow A along with the electric field and shape. Here, the configuration of the waveguide is
The electromagnetic waves emitted from the excitation ports 10, 10' are communicated with the food 12 placed in the heating chamber 9 so that the directions of the electromagnetic waves are opposite to each other. That is, the electromagnetic waves excited from the excitation port 10 have a directivity similar to light, and a strong electric field appears on the left side of the heating chamber 9, and a strong electric field appears on the right side of the excitation port 10' for the above-mentioned reason. Therefore, the high frequency energy applied to the food 12 becomes relatively uniform. In addition,
If the length of the waveguide 1 connecting the respective excitation ports 10, 10' is the internal wavelength λg, the phase of the electromagnetic waves supplied to the heating chamber 9 will be reversed by making it an integer multiple of λg/4. It is also possible to eliminate interference caused by mutual electromagnetic waves.

In addition, each excitation port 10, 10' is connected to the waveguide 1.
The width of the excitation port,
It can be adjusted appropriately by changing the length, position, and angle. Furthermore, a shelf 1 for storing food in the heating chamber 9 is provided.
By changing the position of 3, it was possible to adjust the amount of electromagnetic waves from each excitation port.

In this way, according to this embodiment, electromagnetic waves are supplied to the food from the upper and lower surfaces of the heating chamber, respectively, and electromagnetic waves are also supplied to the left and right sides of the heating chamber from the respective excitation ports, so that the food is It can absorb more high-frequency energy, and has the effect of enabling extremely uniform heating compared to conventional single excitation ports that supply electromagnetic waves with a single directivity to the heating chamber. have

Effects of the invention As described above, according to the invention, the following effects can be obtained.

(1) Uniform heating can be achieved by supplying high-frequency electromagnetic waves with different directivity into the heating chamber using a single high-frequency oscillator.

(2) Since the amount of high-frequency electromagnetic waves in each direction can be varied by supplying high-frequency electromagnetic waves from multiple directions with different directivity, it is possible to easily create the desired electric field pattern in the heating chamber.

(3) By supplying high-frequency electromagnetic waves from multiple directions with different directivity, the amount of high-frequency electromagnetic waves from each direction can be varied by changing the position of the food in the heating chamber, and the amount of high-frequency electromagnetic waves from each direction can be varied to achieve the optimum depending on the properties of the food. Can be heated.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a conventional high-frequency heating device equipped with radio-wave stirring blades, and FIG. 2 is a cross-sectional view showing the structure of an embodiment of the present invention. 1... High frequency oscillator, 2... Waveguide, 3... Heating chamber, 4... Radio stirring blade, 5... Electric motor, 6...
Food, 7... Excitation port, 8... High frequency oscillator, 9...
...heating chamber, 10,10'...excitation port, 11...waveguide, 12...food.

Claims (1)

[Scope of utility model registration request] It is equipped with a heating chamber, a high-frequency oscillator that supplies high-frequency energy to the heating chamber, and a waveguide that propagates the high-frequency electromagnetic waves oscillated by the high-frequency oscillator, and communicates with opposing positions in the heating chamber space through a single waveguide. A high-frequency heating device characterized in that at least two or more excitation ports are provided, and a waveguide is arranged so that the directions of electromagnetic waves in opposing excitation ports are opposite to each other.