JPS5912593A - 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 relates to improving radio wave distribution within a heating chamber of a high frequency heating device.

Conventional structure and its problems Conventionally, there is a turntable method in which the food table is rotated as a method to equalize the distribution of radio waves in the heating chamber of high-frequency heating equipment, but in this conventional method, radio waves are transmitted from the top of the heating chamber. Because it is a structure that emits radio waves, the distance from the radio wave radiation source to the food is long, so the radio waves go around and reflect on the heating chamber walls before being absorbed by the food, and are attenuated to a certain extent before being absorbed by the food. However, there were drawbacks such as poor heating efficiency and weak heating in the center of the heating chamber.

Furthermore, some products cannot be used with a turntable, and in that case, it is necessary to use a method other than a turntable to equalize the radio wave distribution. It is extremely difficult to achieve a uniform radio wave distribution using any other method, so it was impossible to make the heating chambers exactly the same.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and provides a high-frequency heating device that has good heating efficiency and radio wave distribution, and also allows the use of a shared heating chamber even for models that do not use a turntable, allowing for comprehensive rationalization. The purpose is to provide.

Structure of the Invention In order to achieve the above object, the present invention comprises a heating chamber, a high-frequency oscillator, a waveguide for transmitting the radio waves oscillated by the high-frequency oscillator, and a heating chamber that connects the waveguide and the heating chamber to a bottom wall of the heating chamber. It has an antenna that couples at the center, and a coupling hole that couples the heating chamber with a waveguide provided at a point away from the antenna by at least % wavelength, and the heating chamber of the antenna has a food product made of a dielectric material at the tip thereof. It has a configuration in which the food table is connected and the antenna is rotated, and radio waves are directly radiated from the rotation axis and coupling hole of the food table (turntable), so the distance in the food trench is short and heating efficiency is high. . In addition, in the case of a model that does not use a turntable, if you remove the food table at the tip of the dipole antenna and attach a horizontal antenna instead, it becomes a rotating antenna, so the basic open structure can be completely shared, reducing rationalization, etc. It has the following effects.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a main body, and a heating chamber 2 is located inside. A front opening of the heating chamber provided for taking food in and out can be opened and closed by a door 3.

Reference numeral 4 denotes a high frequency oscillator, and the radio waves oscillated thereby are transmitted through a waveguide 5 and radiated into the heating chamber from the bottom of the heating chamber through a coupling hole 19 between the waveguide and the heating chamber and a dipole antenna 6.

The dipole antenna 6 is provided approximately at the center of the bottom wall of the heating chamber, and the coupling hole 19 is provided approximately % wavelength or more from the dipole antenna 6 toward the rear of the heating chamber.

A food table 7 is connected to the tip of the dipole antenna 6 in the heating chamber, and is made of a dielectric material, and is detachably connected to the dipole antenna in order to facilitate cleaning of the bottom wall of the heating chamber.

Reference numeral 8 denotes a rotary drive shaft made of a dielectric material connected to the inner end surface of the waveguide of the dipole antenna, which passes through the waveguide wall and is connected to the pulley 9, and is connected to the belt 10 and the pulley 9'.
It is rotationally driven by a motor 11 via a motor 11, thereby rotating the dipole antenna and the food table.

The pulley 9 is provided with a plurality of rollers 12 in order to receive the load of the dipole antenna and the food table in the blasting direction. The end face of the dipole antenna 6 connected to the food table 7 has a diameter of approximately 74mm or more to prevent the food table from melting due to local electric field concentration at the tip of the antenna. And it's thicker than the other parts. This also provides a more stable mechanical connection with the food platform.

Reference numeral 13 denotes a sealing plate for sealing the coupling port with the dipole antenna provided on the bottom wall of the heating chamber, which is made of a dielectric material and also serves as a rotation bearing for the dipole antenna.

20 is a waveguide for guiding the radio waves emitted from the coupling hole 19 into the heating chamber so that they are more efficiently absorbed by the food, and has a shape of 9 that widens from the coupling hole toward the food. There is. Reference numeral 21 denotes a lid made of a dielectric material, which prevents food gas and the like from entering the waveguide from this portion.

On the other hand, a plurality of reflective surfaces 4, 15 and 16 are provided on the bottom wall of the heating chamber on the opposite side of the coupling hole 19 when viewed from the dipole antenna, thereby efficiently reflecting the radio waves radiated in the horizontal direction from the dipole antenna. , and reflect it towards the food.

FIG. 2 shows an example of uniformizing the radio wave distribution using the same heating chamber as in FIG. 1 but without using a turntable. A fixed food table 18 is provided at the bottom of the heating chamber instead of a rotary food table, and a horizontal portion 17 of an antenna constituting a rotary antenna is connected to the tip of the dipole antenna instead of the food table. has been done. In the case of Figure 1, the position of the radio wave is fixed and the food itself rotates, whereas in Figure 2, the position of the food is fixed and the position of the radio wave is rotated instead. However, all other structures except the shape of the food mounting table and the antenna can be made completely the same.

Effects of the Invention According to the present invention as described above, the following effects can be obtained.

(1) Since radio waves are emitted from below the rotating food table, the food is close to the radio wave radiation source, and therefore heating efficiency is high.

(Oan) Since the dipole antenna is connected to the center of the turntable, it is easy to strengthen the radio wave distribution in the center, which was previously difficult.

(3) Since the tip of the dipole antenna connected to the turntable has a large diameter of approximately 2/4 or more, it is possible to prevent abnormal electric field concentration at the tip of the antenna, and furthermore, it is possible to prevent abnormal electric field concentration at the tip of the antenna. It is possible to strengthen the radio wave distribution over a wider range.

(→ Since another power feeding opening is provided at a distance of two wavelengths from the antenna installed approximately in the center of the heating chamber toward the rear of the heating chamber, feeding power only from the antenna will cause the feed opening to reach the bottom center of the food. The antenna is heated too strongly compared to the upper part, but the radio waves from this other feeding port heat the surrounding area, which is difficult to heat by the antenna, and some of the radio waves are not directly absorbed but are reflected by the side walls of the heating chamber and the soil wall. Since the heat is absorbed from the top of the food, the top and bottom of the food can be heated evenly and in a well-balanced manner.

Especially if the food table is a fixed type, if you install another power supply port at the rear of the heating chamber, in the case of a small load, food is rarely placed directly above it, and in most cases, the radio waves from this Most of the energy is not directly absorbed by the food, but is reflected from the side walls and soil walls of the heating chamber, and then absorbed from the top of the food.

(Since power is supplied from below the return table, there is no need to provide any openings for power supply in the earthen walls of the heating chamber.
The inside of the heating chamber feels clean and is therefore easy to clean.

(＠ It is possible to change from a turntable system to a rotating antenna system by simply changing the food table and antenna, so it is easy to design for changes, and the standardization and commonization of parts can improve overall performance. rationalization will be carried out.

(7) Since it serves as both the rotary drive shaft of the turntable and the antenna, the structure is simple and costs can be reduced.

(8) Since a plurality of reflective surfaces are provided on the bottom wall of the heating chamber on the opposite side of the coupling hole 19 when viewed from the antenna, the radio waves radiated horizontally from the antenna are efficiently reflected toward the food, increasing heating efficiency. It can be improved.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view of a high-frequency heating device showing an embodiment of the present invention, and FIG. 2 is a side cross-sectional view of the same device in the form of an antenna. 1...Main body, 2...Heating chamber, 4...
...High frequency oscillator, 5... Waveguide, 6...
... Antenna, 7... Food mounting table, 14, 15,
16@... Reflective surface, 19... Connection port, 2
0... Waveguide.

Claims (1)

[Scope of Claims] (1) A heating chamber that stores food, a high-frequency oscillator that supplies high-frequency power into the heating chamber, a waveguide that transmits the radio waves oscillated by the high-frequency oscillator, and the waveguide. an antenna coupled to the heating chamber at approximately the center of the bottom wall of the heating chamber; a food mounting table made of a dielectric material connected to the tip of the antenna; A high-frequency heating device comprising a coupling hole for coupling a waveguide provided at a point and a heating chamber, and configured to rotate the antenna. () The high-frequency heating device according to claim 1, in which a waveguide with a shape that widens toward the end is provided around the heating chamber side of the coupling hole between the heating chamber and the waveguide. The high-frequency heating device according to claim 1, wherein a plurality of different reflecting surfaces are provided on the bottom wall of the heating chamber on the opposite side of the heating chamber. The high-frequency heating device according to claim 1, wherein the high-frequency heating device is arranged behind the antenna when viewed from the front.