JPS6364874B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency heating device that connects a waveguide and a heating chamber through an opening and has a stirrer.

Conventionally, exciting a standing wave mode that mainly has a vertical electric field component in the heating chamber of a high-frequency heating device has been used in microwave ovens, etc., because the standing wave mode is stably excited under various loads. This is a very important condition for improving the distribution of food heating equipment. However, as shown in FIG. 1, when high-frequency electromagnetic waves from a magnetron 1, which is a high-frequency oscillator, are coupled to the heating chamber 4 through the waveguide 2 and the opening 3, the direction of the electric field 5 changes horizontally at the opening 3.
A standing wave mode having a vertical electric field could not be excited in the heating chamber 2.

Further, when the waveguide 2 and the heating chamber 4 are coupled by an antenna 6 as shown in FIG. 2, it is possible to excite a standing wave mode having a vertical electric field 5 in the heating chamber 4. However, with this structure, the tip of the antenna 6 protrudes into the heating chamber 4, which not only reduces the effective volume of the heating chamber 4, but also causes spark discharge in the high-frequency electric field if food particles get on the antenna 6. Furthermore, since the antenna 6 is required, the configuration becomes complicated, leading to an increase in cost.

In addition, in the standing wave mode, which has a change in electric field strength between even and odd numbers, when the load is placed at the center, the center is heated strongly, and the center is weakened due to absorption of radio waves, etc., which is compensated for and the distribution is uniform. However, since there is no electric field at the center of the heating chamber 4, this standing wave mode could not be excited from the center. Therefore, when a plurality of loads are placed, the heating degree of each load is different. Furthermore, the directionality of the radio waves from the high-frequency oscillator also occurs, and the degree of heating differs between the side of the heating chamber where the high-frequency oscillator is attached and the opposite side.

The purpose of the present invention is to improve the heating distribution by exciting a standing wave mode within the heating chamber in a configuration in which the waveguide is connected to the heating chamber through an aperture.

Furthermore, the purpose is to obtain stable distribution performance even against load fluctuations that excite standing wave modes with vertical electric fields.

In order to achieve the above object, the present invention provides a plurality of heating chambers with different dimensions in which the dimensions of the heating chamber are such that the standing wave mode resonates, and the electric field direction and position of the standing wave mode are made to match the electric field direction and position of the waveguide. By having this opening, it is possible to excite the standing wave mode that cannot be excited from the center of the heating chamber wall, and also to eliminate the directionality of the radio waves of the high frequency oscillator, so that multiple loads can be heated equally.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 3, a door 7 is provided so that it can be opened and closed by a handle 8, and a control knob 9 can control the oscillation of a magnetron 1, which is a high frequency oscillator. Further, in this embodiment, since the air can be heated with gas or electricity and cooking can be done in an oven, a temperature control knob 10 is provided.

In FIG. 4, high-frequency electromagnetic waves from a magnetron 1, which is a high-frequency oscillator, pass through a waveguide 2, pass through openings 3a and 3b, and enter a heating chamber 4. Air from a fan 11 for cooling the magnetron 1 and electrical components enters the heating chamber 4, rotates a stirrer 12 that stirs the radio waves, and exits the main body.

On the other hand, the dimensions of heating chamber 4 are It is based on the formula. Here, λ is the wavelength, A, B,
C is the width, depth, and height dimensions of the heating chamber 4, m, n,
p is the number of changes in the electric field of the standing wave mode occurring in each direction and is an integer. In the case of an embodiment of the present invention, if m=4, n=5, and p=0, λ
= 122mm, A = 290mm and B = approximately 290mm.

FIG. 5 is a diagram schematically showing a cross section taken along line XX in FIG. 4. In FIG. 5, standing wave modes 4, 5, and 0 modes are occurring within the heating chamber 4. This has four electric field changes in the width direction and five changes in the depth direction.
Since there is no change in the electric field in the height direction, the electric field 5 is all vertical. This electric field 5 is schematically shown as ○†

Claims (1)

[Claims] 1. A heating chamber that stores an object to be heated, a high-frequency oscillator that supplies high-frequency electromagnetic waves into the heating chamber, and a waveguide that couples the heating chamber and the high-frequency oscillator, and the waveguide and the heating chamber are connected to each other. The electric field position and direction of the standing wave mode of the vertical electric field that is coupled through a plurality of openings and generated in the heating chamber is made to match the electric field direction and position of the waveguide, and the electric field maximum point of the standing wave mode is aligned with the electric field position and direction of the vertical electric field that is generated in the heating chamber. A high-frequency heating device configured with an opening.