JPS60143591A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is characterized by 1. The present invention relates to the configuration of a transmission line connecting a heating chamber to a high-frequency heating device of a high-frequency heating device equipped with two high-frequency sources in the S and M frequency bands (for engineering, science, and medical use), 915 MH2 band and 2450 MH2 band.

However, the configuration of the conventional example has a simple problem: 1. One of two frequencies, 2450 MH2 and 915 MH2, which are recognized as S and M frequencies, is often used. However, due to the difference in wavelength between these two frequency bands, there are differences in the degree of penetration into food and the radio wave distribution inside the heating chamber.
It has been pointed out that better cooking and heating can be achieved by using both MH2 appropriately or at the same time.

As a means for realizing such a cooking means, a high-frequency heating device that heats the room by guiding two different high-frequency waves to a common heating chamber can be considered. However, here, the power supply configuration (oscillation source, transmission line, and antenna) of a conventional high-frequency heating device that uses only a single frequency is 2450MH2 band and 915MH2 band.
If both H2 bands are installed in one heating chamber, the high frequencies generated by the oscillation sources of the two frequency bands will propagate through each antenna to the other's oscillator, resulting in wasted energy. This not only causes significant power loss, but also heat generation and damage caused by this.

In particular, as explained in the example section, 915MH
When using two frequency bands, 2 and 2450MH2,
Due to the characteristics of the oscillator itself, solid-state oscillators using solid-state active elements such as transistors are used in the 915MH2 band, and 2450MHz
The most rational configuration is to use a magnetron for the MH2 band.

However, solid-state oscillators are generally constructed by wiring transistors on a circuit board called a microstrip line, so the output circuit part of the solid-state oscillator itself has
Only specific frequencies as needed (in this case 915MH)
2 bands] can be constructed relatively easily. On the other hand, since magnetrons generally have a cavity resonator that also serves as an anode as their basic configuration, it is extremely difficult to add additional functions such as a filter circuit. When constructing a high-frequency heating device that uses frequencies, it was necessary to block other radio waves in areas other than the magnetron.

OBJECTS OF THE INVENTION The present invention provides a means for solving such conventional problems, and it is an object of the present invention to completely eliminate the interference caused by at least the radio waves in the 915 MH7 band to the oscillating source in the 2450 MH2 band, out of the mutual interference between the two oscillation sources. The purpose is to remove it.

Structure of the Invention In order to achieve this object, the present invention utilizes the 915MH2 band and 2
Of the transmission lines that guide the radio waves generated by the two high frequency generators, each of which generates high frequencies in two frequency bands of the 450 MH2 band, to the heating chamber, at least the radio waves in the 2450 MH2 band are guided. It is equipped with a wave tube.With this configuration, 915MH2
The radio waves in the 2450 MH2 band will no longer propagate to the high frequency generator in the 2450 MH2 band, and the high frequency generator in the 2450 MH2 band will
15MH7: Can completely remove the influence of band radio waves.

Description of examples The following is a 5-page explanation of one embodiment of the present invention using FIG. Ru.

In FIG. 1, an object to be heated 9 is housed in a heating chamber 1, and a high frequency wave serving as a heating source is introduced. 915MH
A high-frequency generator that generates high-frequency waves in two bands uses a solid-state oscillator 3 that uses a solid-state element such as a transistor as an active element.
The high frequency generator for the 2450MH7: band is equipped with a magnetron 2. Here, the solid-state oscillator 3 is used as the oscillation source for the 915 MH2 band, and the magnetron 2 is used as the oscillation source for the 2450 MH2 band. This is because the anode, which serves as the resonator, becomes very large and is not very practical.

The 915MH2 band radio waves generated by the solid-state oscillator 3 are radiated from the antenna 6 into the heating chamber 1 via the microstrip line 5, and are radiated to the 2450MH band generated by the magnetron 2.
The two-band radio waves are configured to be radiated into the heating chamber 1 from the opening 8 via the waveguide 4. In particular, the waveguide 4 has a cutoff frequency of 91 cm for the 6-Bage main mode (the one with the largest cutoff wavelength) determined by its cross-sectional shape (including size).
The one designed to be 5MH7 or more and less than 2450MH2 is used. For example, in the case of a rectangular waveguide, the main mode is called the TE10 mode, and its cutoff frequency is generally determined by the length of the long side called the H-plane. For example, if the length of this long side is 90 mm, the cutoff frequency will be approximately 1666 MH2, which satisfies the above conditions.

According to the above configuration, the waveguide 4 transmitting radio waves in the 2450 MH2 band has a cut-off frequency of 915 MH7, or more, and 2450 MH2 band.
Since it is set to be less than 450MH2, the Z-band radio waves transmit this (2450M generated by magnetron 2), but the 915MH2 generated by solid-state oscillator a
Since the band radio waves are below the cutoff frequency, they are not transmitted through the waveguide 4 and therefore have no effect on the magnetron 2.

Effects of the Invention As described above, the high frequency heating device of the present invention provides the following effects.

Radio waves in the 2450 MH2 band are transmitted through a waveguide7,--
-... Because of the cut-off characteristics unique to waveguides, radio waves in the 915 MHz band can be completely blocked.

Therefore, in a high-frequency heating device that has power feeders for different frequency bands, 915MH2 band and 2450MH2 band,
An efficient and highly reliable high-frequency heating device is constructed that completely eliminates interference caused by radio waves in the 915 MH2 band to the oscillation source in the 2450 MH2 band.

[Brief explanation of the drawing]

The figure is a cross-sectional view of a high-frequency heating device according to an embodiment of the present invention. 2...Magnetron, 3...Solid oscillator, 4... Waveguide.

Claims (1)

[Claims] two high frequency generators that generate high frequencies in a first frequency band and a second frequency band, a heating chamber that accommodates an object to be heated and introduces high frequencies in the two frequency bands, and a second frequency band. A high-frequency heating device comprising a waveguide serving as a transmission line for transmitting radio waves from the high-frequency generator to the heating chamber and having a cut-off frequency higher than a first frequency band and lower than a second frequency band.