JPS6359234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves a high frequency heating device in terms of uniform heating.

As uniform heating means for high-frequency heating devices, there are known methods such as a stirrer that diffusely reflects high-frequency waves, a rotating antenna that emits high-frequency waves, a turntable that rotates the object to be heated, and a method of providing a large number of high-frequency supply ports on the peripheral wall of the heating chamber. . In any case, through numerous cut-and-try experiments, the heating unevenness has been reduced to a level that can be put to practical use, but many still do not have sufficient performance.

The present invention provides a high-frequency heating device with extremely low heating unevenness through a small number of confirmation experiments by combining a slot antenna array (slot array antenna) consisting of a plurality of slots having a specific dimensional relationship with a turntable. With the goal.

An embodiment of the high-frequency heating device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of essential parts showing an embodiment of the high-frequency heating device of the present invention. 1 is a high frequency oscillator that generates high frequency energy; 2 is a high frequency oscillator 1
This is a waveguide that connects the heating chamber 3 to the heating chamber 3. The heating chamber 3 and the waveguide 2 are formed from metal plates. A turntable 5 is provided at the lower part of the heating chamber 3 on which a heated object 4 such as food is placed and rotated. The part where the waveguide 2 is connected to the heating chamber 3 has a slot width B1 of λg/4 or less up to λg/16 with an interval A1 of λg/2 ±λg/4 (λg: wavelength inside the waveguide 2). A slot antenna row (slot array antenna) consisting of two slots 6 and 7 having B2 is provided. In particular, in the case of a large heating chamber 3, as shown in FIG. A slot antenna array consisting of three slots 6, 7, 8 may also be provided. Slot 6, 7, 8
The number of slots is selected so that the slot 6 provided at the tip of the waveguide 2 is close to the center line 9 of the upper surface of the heating chamber 3 in the horizontal direction with respect to the drawing. 10 is a metal piece provided between slot 6 and slot 7 for adjusting high frequency radiant energy;
This is to reduce the difference in temperature rise value between the vicinity of the center of the heated object 4 and the surrounding area by adjusting the radiant energy from the heated object 4. Furthermore, the turntable 5 reduces variations in temperature rise in the circumferential direction. 11 is also a metal piece that has the same function as the metal piece 10.

In the above configuration, the slot intervals A1, A2
is λg/2±λg/4 because each slot 6, 7, and 8 is placed at the maximum value of the high-frequency current that appears every λg/2 on the inner wall of the waveguide 2 (the direction of the current and the slot are at right angles). This is to efficiently radiate high frequency energy into the heating chamber 3. Furthermore, the reason why the slot widths B1 and B2 are set to λg/4 or less to λg/16 is that the current outside the vicinity of the maximum high-frequency current becomes small, and the component that is not perpendicular to the slot increases and contributes little to the radiated energy. Because they don't. Since each slot 6, 7, 8 requires an expensive dielectric cover (not shown) made of a high frequency transparent heat resistant material, the slot widths B1, B2 are preferably small. However, if it is too small, the waveguide 2 itself may become abnormally heated in general high-frequency heating devices of about 400 to 2000W, so-called microwave ovens or microwave ovens, so in consideration of economic efficiency and prevention of abnormal heating, Although it depends on the high frequency output, it is appropriate for the slot widths B1 and B2 to be about λg/16 to λg/4.

In the high-frequency heating apparatus configured as described above, it has been confirmed in experiments that there is extremely little uneven heating between the center and the surrounding area of the object to be heated 4. Therefore, according to the present invention, a high frequency heating device with very little heating unevenness is provided by combining a slot antenna array (slot array antenna) having metal pieces for adjusting high frequency radiant energy between the slots and a turntable. can do.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a main part of a high-frequency heating device according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the same main part showing another embodiment of the present invention. 1... High frequency oscillator, 2... Waveguide, 3... Heating chamber, 4... Heated object, 5... Turntable,
6, 7, 8...slot, 10, 11...metal piece.

Claims (1)

[Claims] 1 a waveguide connecting a high frequency oscillator to a heating chamber;
A turntable for placing an object to be heated is provided in the heating chamber, a slot antenna array consisting of a plurality of slots provided at a joint between the heating chamber and the waveguide, and the slots of the waveguide. 1. A high-frequency heating device comprising: a metal piece for adjusting high-frequency radiant energy provided at a portion located between the two.