JPS6159112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device, and in particular provides a device for thawing large frozen cakes satisfactorily using high-frequency waves.

Frozen foods have recently become popular in Japan, and the methods for thawing these frozen foods are (1) thawing thin frozen foods with a high frequency of 2450 MHz, and (2) thawing thick frozen foods with a high frequency of 13 MHz. Thaw the food while cooling the outer periphery. This 2
Two methods have been mainly used. The reason for this is
With the high frequency of 2450MHz, it is difficult for radio waves to penetrate inside the food, so thin frozen foods can be thawed, but if the food is thick, the radio waves cannot reach the inside, so 13MHz radio waves using a parallel electrode plate method are used to heat the inside of the food to thaw it. A method was adopted. The area around the frozen food is cooled if the surface of the frozen food thaws first.
This is to prevent skin current from flowing in the melted part, causing further heating and causing it to lose its shape.

The present invention is particularly useful for frozen cakes that have a constant shape.
The purpose is to decompress using 2450MHz radio waves, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side cross-sectional view showing an embodiment of the present invention, in which a heating chamber 2 is provided within a main body 1. As shown in FIG. A door 3 that can be opened and closed is attached to the front opening of the heating chamber 2, and an operation panel 4 equipped with a timer cooking button and the like is attached to the upper part of the door 3. A rotating antenna 6 is supported on the upper wall of the heating chamber 2 by a bearing 8 of a power feed port 7 in a space partitioned by a partition plate 5, and is rotationally driven by a motor 9. Therefore, when the magnetron 10, which is a high frequency generator, oscillates, the high frequency wave is guided into the waveguide 11 and radiated into the heating chamber 2 by the rotating antenna 6. The rotating antenna 6 is made of a non-magnetic material such as aluminum or stainless steel (SUS304), and is connected to the motor 9 by a transmission shaft 12 made of synthetic resin in a waveguide 11.
is connected to the axis of 13 is a bearing for the transmission shaft 12.

On the other hand, a partition plate 14 made of glass or ceramic is also provided on the bottom wall of the heating chamber, and the other power supply configurations are provided approximately symmetrically with respect to the high frequency radiation from the top wall.

In the heating chamber, as shown in the exploded perspective view of FIG. 2, an object to be heated 15 such as a frozen cake is placed in a cap-shaped metal container 17 with a cutout 16 in the center;
It is placed between a metal plate 20 covered with a synthetic resin plate 18 and having a cutout 19 in the center. 21 is a saucer on which the object to be heated is placed.

By doing this, it is possible to weaken the electric field strength at the periphery while leaving the electric field strength at the center of the object to be heated 15 as it is.For example, when a frozen cake is thawed, the center part is thawed first, and As the frozen parts of the frozen parts are thawed, the surrounding frozen parts are also thawed by conduction heat, so that the frozen parts can be thawed neatly without distorting the figure. It goes without saying that the metal container 17 and the metal plate 20 may be constructed of a metal net or a punched plate, etc., since the purpose is to defrost the peripheral part of the object to be heated more slowly than the central part.

Next, a synthetic resin with low dielectric loss is sandwiched between the metal container 17 and the metal plate 20 for capacitive coupling, so there is no discharge between the two, and a cutout in the center of the metal plate 20 is used. Since it covers the portion 19, it is easy to use when taking in and out the heated object.

Furthermore, since the distance a from the center of the object to be heated 15 to the upper antenna 6 and the distance b to the lower antenna 6' are set approximately equal, if equal output is output from the upper and lower magnetrons, the distance to the object to be heated is The electric field strength above and below the center of the object can be made approximately equal, and thawing can be performed uniformly.

As is clear from the above explanation, conventionally, when thick frozen foods were thawed, the outer circumference of the food was cooled using a 13MHz high frequency, but with the present invention, neither a 13MHz oscillator nor a cooling device is required.
A 2450MHz oscillator is sufficient, making it extremely economical. In particular, for a 13MHz oscillator, the oscillator is composed of transistors, vacuum tubes, etc., and two
It required multiple electrode plates to be attached, resulting in high cost and extremely troublesome handling. Furthermore, it was necessary to adjust the matching between the oscillator and the object to be heated each time it was used. Although the device configured in this manner can only be used for defrosting, the present invention can be used for the same purposes as a microwave oven, and therefore the product appeal is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a high-frequency heating device showing one embodiment of the present invention, and FIG. 2 is an exploded perspective view of the main parts thereof. 1... Main body, 2... Heating chamber, 6... Rotating antenna, 10... Magnetron, 15... Heated object,
17...Metal container, 18...Synthetic resin plate, 20
...Metal plate.

Claims (1)

[Claims] 1 A heating chamber provided in the main body, a high frequency generator that radiates high frequency energy into the heating chamber from the upper and lower walls of the heating chamber, and an object to be heated consisting of a metal plate cut out in the center or a synthetic resin plate placed on a metal mesh. and a cap-shaped metal container or a metal mesh container with a cutout in the upper center part covering the object to be heated, and the object to be heated is placed approximately equidistantly from the upper and lower high frequency radiating parts of the heating chamber. High frequency heating device located.