JPS5913835B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that uses high-frequency waves to heat foods and other items for sterilization, cooking, drying, and the like.

Conventional high-frequency heating devices sometimes change the high voltage of a high-voltage circuit in order to vary the high-frequency output, but most of them switch in stages (two stages, three stages).

When cooking food, it would be desirable to be able to switch the output. Depending on the food, there are times when it is better to cook at high power for a short time, there are times when it is better to cook at low power for a long time, and there are times when it is better to cook by switching between high power and low power during cooking. This is because there are various cases where it is better. Furthermore, it would be desirable to use continuous variable switching instead of stepped switching for the output. In addition, in conventional high-frequency heating devices, in order to improve the uniformity of heating the food, a stirrer fan or a turntable has been used alone, or both have been used in combination to reduce uneven heating of the food.

That is, to explain using FIG. 1, the microwave emitted from the magnetron 5 passes through the waveguide 4 and is projected into the open 1. Then, the projected microwaves are either stirred by the stirrer fan 8, which is rotated by the stirrer motor T, or placed on the turntable 2 by rotating the turntable 2 with the motor 3 that rotates the turntable 2. The uneven heating of food was reduced.
However, even these methods are not sufficient, and uneven heating occurs depending on the type, amount, size, shape, etc. of the food. The present invention provides a high-frequency heating device that eliminates the above-mentioned drawbacks, and is a device that allows adjustment of the area of the opening through which microwaves are projected into the oven. Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of the high frequency heating device of the present invention. In the figure, 11 is open, 12 is a turntable on which food is placed, and 13 is turntable 1.
2, 14 is a waveguide for guiding the microwave from the Magneilon 15 into the open 11, and 16a is a waveguide whose opening area on the open 11 side of the waveguide 14 is variable (for example, a in the figure). →L, L→a) is a movable plate provided near the opening, and the shape 30 of this movable plate 16a is, for example, as shown in FIG. e Rectangle etc. can be considered.
Moreover, the movable plate 16b is shown in FIG. 4 (cross-sectional view) and FIG.
As shown in the enlarged top view of the main part of the figure, a spring 20 is used to elastically attach the spring 20 to the open wall near the opening of the waveguide, and the cam 19 is placed in contact with the side wall of the movable plate 16b. It is also possible to configure the cam 19 by rotating it with the rotating shaft 18 of the motor 1Ta.

In this embodiment, the cam 19 also rotates in conjunction with the rotation of the motor 17, and the movable plate 16b can be reciprocated at a constant cycle during the heating operation, making it possible to change the conditions of the high frequency waves irradiated to the load. can. At this time, the movable plate 16b of the present invention is reciprocated in the direction of the arrow in the figure, as shown in FIG. 6 (cross-sectional view) and FIG. 7 (enlarged top view of the main part of FIG. 6), for example. The rotating plate 21 having a plurality of different openings is connected to the oven 1 of the waveguide 14 in the same way as the movable plate 16 described above.
The rotating plate 21 is provided near the opening on the first side, and the rotating plate 21 is connected to the motor 17b.
The opening of the rotating plate 21 can also change the area of the opening of the waveguide 14.

Further, the shape of the opening of the rotating plate 21 is, for example, as shown in FIG. 8A.
, b, etc. are possible. In addition, the movable plate 1
6 or the attachment device of the motor 17 for operating the rotary plate 21 may be determined as appropriate, but depending on the usage conditions, the movable plate 16 or the rotary plate 21 may be manually operated. The present invention is configured as described above.

Here, when the dimension L from the magnetron 15 to the opening of the waveguide 14 that projects radio waves to the oven 11 is varied with the movable plate 16 while the turntable 12 is rotating, the dimension L and the inside of the oven are changed. It has been confirmed that there is a correlation between the high frequency output PO and the high frequency output PO as shown in FIG. 9, and that the output PO changes continuously according to the dimension L.

This is because the alignment state between the magnetron 15 and the oven 11 changes due to the movable plate 16, and the high frequency output changes accordingly. That is, by changing the movable plate 16, the high frequency output can be continuously varied. In addition, each load is placed on the circumference and center position as shown in the diagram above the turntable 12 in Figure 10, and the turntable 12 is moved in the direction of the arrow in the diagram.
When the dimension L from the magnetron 15 to the opening of the waveguide 14 that projects radio waves to the oven 11 is changed in a rotating state, under A load (for example, pudding), the graph in FIG. B load (e.g. Chawanmushi)
The graph will look like the one in Figure 12.

That is, the state of the electric field strength is different between the A load and the B load, and in the A load, when L is t1 or T2, the electric field strength of each load 4 to 8 becomes equal, and uneven heating does not occur. Also, in the case of load B, the electric field strength of each load 4 to 8 becomes equal only when L is T3, and uneven heating does not occur. Therefore, if L is constant, the uniformity of the A load will be good and the uniformity of the B load will be bad.

Therefore, in order to improve the uniformity of all foods, non-uniform heating can be eliminated by selecting the above-mentioned L dimension suitable for the food.

When controlling the L dimension from the outside, the device shown in FIG. 13 (enlarged front view of main parts) is convenient.

That is, 31 is an operating section of the microwave oven, 32 is a food menu, and 33 is provided on the operating section 31, and by moving the movable plate 16 in accordance with the scale of the menu 32, uniform heating of the food and high frequency heating can be achieved. It consists of a variable electric field strength knob or a high frequency variable knob, etc., which are configured to adjust the output. Therefore, set the knob 33 to menu 3.
You can easily heat food evenly by simply adjusting the settings in step 2. As described above, according to the high-frequency heating device of the present invention, it is possible to achieve continuous variable switching of the high-frequency output with a simple configuration rather than circuit switching.
Uniform heating can be achieved by adjusting the amount, size, shape, etc.

In addition, the present invention may be used alone or the conventional star rough fan,
By using a turntable in combination, it has more uniformity than before.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional high-frequency heating device, Fig. 2 is a cross-sectional view of a high-frequency heating device of the present invention, Fig. 3 A, b, and c are top views of the same embodiment, and Fig. 4 is another embodiment. A cross-sectional view showing
Fig. 5 is an enlarged top view of the main parts of the same embodiment, Fig. 6 is a sectional view showing another embodiment, Fig. 7 is an enlarged top view of the main parts of the same embodiment, and Figs. 8A and b are the same embodiments. Top view for example,
FIG. 9 is a characteristic diagram showing the relationship between the movable plate position and high output power according to the present invention, FIG. 10 is a load arrangement diagram used to explain the operation of the present invention, and FIGS. FIG. 10 is a characteristic diagram showing the experimental results, and FIG. 13 is an enlarged front view of main parts of another example. 11...Oven, 14...Waveguide,
15...Magnetron, 16...Movable plate, 31...Operation section of microwave oven, 32...
...Food menu 33...High frequency variable knob.

Claims (1)

[Claims] 1. In a high-frequency heating device equipped with a waveguide for guiding microwaves from a magnetron into the oven, a movable plate is provided to adjust the dimension between the magnetron and the opening of the waveguide in accordance with the food menu. A high-frequency heating device characterized in that a high-frequency variable knob formed by moving this movable plate is provided on an operating section.