JPS6025875B2 - heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave power supply method for a heating chamber that realizes uniform heating when high frequency heating is performed in a heating device. The purpose is to adjust the electric field strength to the cumulative electric field strength at the outer periphery by constantly changing the electric field strength.

In general, this type of heating device uses a so-called turntable method in which the object to be heated is heated while rotating to prevent uneven heating at high frequencies. The problem is the condition.

In other words, the electric field in the central part of the turntable hardly changes even when the turntable rotates, and it is difficult to maintain a balance with the outer peripheral part, where the electric field constantly changes due to the exposure field caused by the shape of the heating chamber. As a result, uniform heating is often not achieved. In particular, it was difficult for the radiated electric field to reach the bottom of the center, and even though the outer periphery was always heated, the bottom of the center sometimes remained almost unheated. The present invention has been made to eliminate such problems with uniform heating, and embodiments thereof will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic side sectional view showing the configuration of an embodiment of the present invention.

A heating chamber 3 for heating the object to be heated 2 is provided inside the main body 1, an opening 4 for supplying high frequency power to the heating chamber 3, and a waveguide for guiding the high frequency waves oscillated by the high frequency oscillator 5 to the Sekiguchi. 6 is provided outside the heating chamber 3.

A metal rotary table 9 having a magnet 8 is provided on the bottom wall 7 of the heating chamber so as to be rotatable by a roller 101, and a saucer 11 on which the object to be heated 2 is placed is provided on the rotary table.

Another magnet 12 is connected to the pulley 1 outside the heating chamber 3 on the opposite side of the magnet A8, with the bottom wall 7 of the heating chamber sandwiched therebetween.
The pulley 13 is rotatably supported by a bearing 14 provided approximately at the center of the bottom wall 7 of the heating chamber. The pulley 13 has circuits and components configured so that it constantly rotates while the motor 15 supplies high frequency waves to the heating chamber 3. The rear wall 16 of the heating chamber is provided with a embossed portion 17 which is embossed on the 15 side outward from the heating chamber. A metal plate 18 is rotatably supported in the support portion 17. This metal plate 18 is bent at least in part so that the angle formed with the rear wall 16 of the heating chamber is at an angle other than parallel, and by rotating the metal plate 18, the opening □4 is bent. The distance up to 18 is changed. Reference numeral 19 denotes a drive device for rotating the metal plate 18, which includes a pulley 21 provided on a part of a rotating shaft 20 that pivotally supports the metal plate 18, and is connected to the output shaft of the motor 15 by a rubber belt 22. The metal plate 18 is constantly rotated during high-frequency heating.

FIG. 2 is a perspective view showing the vicinity of the waveguide 6, in which the closure 4 is shaped like a parallelogram with the short side parallel to the rear wall 16 of the heating chamber,
The side wall 23 of the waveguide 6 is provided on the upper wall 24 of the heating chamber so as to be parallel to the rear wall 16 of the heating chamber.

In other words, it is along the short side of the parallelogram Sekiguchi 4. The terminal end 25 of the waveguide 6 on the side of the high-frequency oscillator 5 is short-circuited at an angle perpendicular to the side wall 23, and its position is such that it can be sufficiently matched with the antenna 26 of the high-frequency generator 5. In this embodiment, antenna 2
The pitch between the center of 6 and the end portion 25 is 21 willows. On the other hand, the other terminal end 27 of the waveguide is perpendicular to the terminal end 25 in accordance with the angle formed by the long side of the closed opening 4, and Q(0
<90 degrees).

Furthermore, the surface formed by this terminal end portion 27 is arranged to form a certain angle 8 (0<8<90 degrees) with the upper wall 24 of the heating chamber, which is not perpendicular or parallel. In this example, Q=27.80
, B=49.30. Further, the distance from the antenna 26 of the high-frequency oscillator 5 is set to be greater than the side of the short side of the opening 4 wound on the side opposite to the rear wall 16 of the zero-force heat chamber. Furthermore, within the heating chamber 3, a heater 28 capable of electric heating is supported and fixed near the upper wall 24 of the heating chamber by a shaft 29 as another heating means.

Further, on a part of the front surface of the main body 1, on the operation panel 30, there is provided a switch 32 for a switch 31 that enables switching of the power to the high frequency oscillator 5 and the heater 28. By operating the camera 32, it is possible to arbitrarily select either high-frequency heating or electric heating, or to perform heating at the same time. By adopting the above configuration, it has become possible to provide the following features compared to conventional heating devices of this type. In other words, the radio waves emitted from the antenna 26 are transmitted through the waveguide 6.
As shown in FIG.
Head to the side.

The radio waves radiated to the vicinity of the rear wall 16 of the heating chamber are further reflected at the same angle of incidence with respect to the metal plate 18, depending on the state of the metal plate 18, and are directed toward the object to be heated, thereby heating the object. By changing the angles Q and B of the plane formed by the terminal end 27 of the waveguide 6, it is possible to adjust the amount and angle of the radio waves directed toward the rear wall of the heating chamber, that is, the amount and angle directed toward the object to be heated. It became. In other words, in the conventional method, the radio waves exiting the Sekiguchi 4 were directed directly toward the object to be heated 2, and the only thing to do was to adjust the angle of approach, so that only the target could be adjusted. According to the present invention, the radio waves leaving the Sekiguchi 4 are divided into those directed directly to the object to be heated 2 and those directed toward the rear wall 16 of the heating chamber.
At the splitting stage, it became possible to adjust the angle of approach to the heated object from the other direction for at least a part of the heated object by changing the ratio of the splitting, making it possible to adjust the electric field in a very fine-grained manner. . Further, the radio waves directed toward the rear wall 16 of the heating chamber reach the metal plate 18, but the state of the metal plate 18 is constantly changing and the distance from the closed opening is changed, so the radio waves that reach the metal plate 18 When it is reflected and tries to head into the heating chamber again, its direction and phase will constantly change (equivalently, the effect of changing the depth of a part of the wrinkled portion 17 can be obtained). The radio waves that reach the heated object 2 are so-called bounded radio waves, and it has become possible to eliminate the inconveniences where the electric field is always concentrated in one part, causing local heating, and other parts not being heated at all. As mentioned above, the ratio between the radio waves that are sideways and the radio waves that go directly from the opening □4 to the object to be heated can be adjusted arbitrarily by the angles Q and 8 formed by the terminal ends, so the size of the heating chamber can be adjusted. If Q and 8 are determined to have an appropriate angle depending on the height, the electric field near the center of the turntable can be changed with the necessary width. The electric field at the center of the turntable, which varies depending on the shape, material, quantity, etc., can now be kept at a nearly constant value, resulting in a significant improvement in the ability to prevent uneven heating.

FIG. 5 shows experimental data on heating unevenness performance (temperature difference in the finished state) in this example.

As shown above, the present invention has been able to significantly improve the performance of preventing uneven heating in high-frequency heating compared to conventional heating devices that only have a turntable function. Furthermore, by implementing this invention, the following effects could be obtained. First, the saucer 11 can be made of metal, making it possible to switch between electric heating and high-frequency heating in so-called open ranges that have heating devices that use electric heating or gas combustion without replacing the saucer, greatly improving usability. Now I can do it.
Conventionally, this type of heating device requires two types of saucers, one made of metal for electric heating and the other made of heat-resistant glass for high-frequency heating, depending on the characteristics of each. One of the reasons for this is that in order to achieve uniform heating during high-frequency heating, the object to be heated must be suspended above the heating chamber wall (metal) using an insulating material such as glass. If this was not done, the center bottom would hardly be heated even if the turntable method was used. However, according to the present invention, by adjusting Q and 8 mentioned above with the metal plate 18, it has become possible to set the central bottom part to be heated equally as the outer periphery. Now, it has become possible to make the saucer for high-frequency heating metallic, and this means that it is now possible to use the same metal saucer and saucer, which is convenient for electric heating. Ta. As a result, it became possible to instantly switch between high-frequency heating and electric heating without replacing the saucer, and it also became possible to heat evenly at the same time, greatly improving usability and heating performance. Of course, it goes without saying that the cost of the product could be reduced by replacing the glass saucer with a metal saucer. Furthermore, in the present invention, by providing a structure that generates air flow by rotating the shape of the metal plate 18, it can also be rotated during heating using heat other than during high frequency heating, thereby providing a so-called hot air circulation function. This was highly effective in improving heating efficiency during thermal heating and preventing uneven heating.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a high-frequency heating device showing one embodiment of the present invention, FIG. 2 is an enlarged perspective view of a waveguide portion of the same part, and
The figure shows the traveling direction of radio waves due to Q of the present invention, FIG. 4 shows the change in the traveling direction of electromagnetic waves due to the rotation of the metal plate 18 of the present invention, and FIG. 5 shows heating unevenness. 4...Closed mouth, 5...High frequency oscillator, 6.
... Waveguide, 7 ... Heating chamber bottom wall, 16.
...Heating chamber rear wall, 17...Shibori part, 1
8...Metal plate. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A heating chamber for storing and heating an object to be heated is provided in the main body, and a part of the upper wall of the heating chamber forming this heating chamber has a shape of a parallelogram other than a rectangle for high-frequency power supply. An aperture is provided, and the aperture and a high-frequency generator provided outside the heating chamber are aligned so that the end face on the aperture side is at an angle formed by the long side of the opening, and further terminated at an angle other than perpendicular or parallel to the end face on the antenna side of the high-frequency generator. The rear wall of the heating chamber is provided with an embossed part that protrudes outside the heating chamber, and a metal plate that rotates at least during high-frequency heating and stirs the radio waves is provided near the embossed part, and the heating chamber A heating device characterized in that a turntable mechanism for rotating an object to be heated is provided near a bottom wall. 2. The heating device according to claim 1, wherein the tray on which the object to be heated is placed in the turntable mechanism is made of metal.