JPS5921149B2 - High frequency heating device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a high-frequency heating device, and its purpose is to uniformly distribute radio waves (high-frequency energy) in a heating chamber to perform effective heating. .

The structure and operation of the high frequency heating device will be explained with reference to FIG.

Reference numeral 1 denotes a heating chamber of a high-frequency heating device, and six surrounding surfaces are made of metal, and an opening 3 is provided at the front surface of the heating chamber 1 through which a heated object 2 can be taken in and taken out.

Reference numeral 4 denotes a metal door, which is electrically and magnetically isolated from the outside at the opening 3.

Reference numeral 5 denotes a high frequency oscillator, and radio waves emitted from the high frequency oscillator 5 are guided to the heating chamber 1 by a waveguide 6 provided on the upper surface of the heating chamber 1.

□ is a joint between the waveguide 6 and the heating chamber 1, where the inner conductor extends from the upper surface of the waveguide 6 toward the heating chamber 1 and the outer conductor extends from the lower surface of the waveguide 6 toward the heating chamber 1. A coaxial line 10 is formed with the conductor 9. Coaxial line 10 with waveguide 6
After passing through the coaxial line 10, the radio waves guided up to It is designed to heat 2. In a conventional high-frequency heating device (see FIG. 3), an inner conductor 8 and an outer conductor 9 forming a coaxial line 10 are arranged concentrically.

Furthermore, the standing waves of the radio waves guided to the coaxial line 10 are not symmetrical about the central axis Y of the coaxial line 10, but are
The direction of the electric field (arrow) in the inner conductor depends on the direction of the standing wave (broken line) in the waveguide 6 near the coaxial line 10, and the inner conductor 8 and outer conductor 9 are arranged concentrically. Therefore, the electric field within the coaxial line 10 tended to become stronger as the electric field of the standing wave was stronger. Therefore. The radio waves radiated into the heating chamber 1 have areas with high radio wave density on the side where the electric field of the coaxial line 10 is strong, and when they are absorbed by the object to be heated 2, they are heated from the side with the high radio wave density, resulting in effective heating. I couldn't get any effect. This invention solves the above-mentioned disadvantages, and an embodiment shown in FIG. 2 will be described below.

In the coaxial line 10 of this invention, the central axis y of the inner conductor 8
, and the center axis y2 of the outer conductor 9 are shifted from each other, and the distance between the inner conductor 8 and the outer conductor 9 in the coaxial line 10 in which the standing wave in the waveguide 6 is stronger is made longer, and the distance between the inner conductor 8 and outer conductor 9, which have weaker standing waves, is made shorter. With the above configuration, the impedance of the shorter distance between the inner conductor and outer conductor is smaller than that of the longer distance, and the strong electric field in the waveguide passes through the larger impedance. The electric field passes through the path with smaller impedance, making it possible to make the electric field uniform throughout the coaxial line. Therefore, the radio waves emitted into the heating chamber are emitted uniformly from the tip of the inner conductor, and are evenly absorbed by the object to be heated to uniformly heat it, thereby achieving an effective heating effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a high-frequency heating device, FIG. 2 is an enlarged view of the main parts of the high-frequency heating device of the present invention, and FIG. 3 is an enlarged view of the main parts of a conventional high-frequency heating device. DESCRIPTION OF SYMBOLS 1... Heating chamber, 6... Waveguide 67... Coupling part. 8
...Inner conductor, 9...Outer conductor 610...Coaxial line.
Y,, y2... central axis.

Claims (1)

[Claims] 1. A coaxial line is provided at the joint between the waveguide and the heating chamber, and power is supplied from the tip of this coaxial line, and the inner conductor in the coaxial line with the stronger standing wave in the waveguide and the A high-frequency heating device configured to increase the distance to an outer conductor and shorten the distance between the inner conductor and the outer conductor, which have weaker standing waves.