JPS5847612B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device for heating an object using radio wave energy, and more particularly to a means for controlling the heating of an object to be heated by the device.

It is well known that radio energy in the microwave band is used to heat objects.

A common configuration of such high-frequency heating devices is a structure in which radio waves emitted from a radio wave generation source such as a magnetron are supplied directly or through a waveguide to the inside of a cavity called an open cavity in which the object to be heated is housed. It belongs to the precepts.

In the apparatus having such a configuration, the heating time of the object to be heated is usually controlled by a timer such as a timer.

In this case, it is necessary to adjust the heating time appropriately depending on the type of the object to be heated, that is, the difference in dielectric loss coefficient, the weight, and the initial temperature, that is, the temperature of the object before heating.

If the time adjustment is inappropriate, the result will be that the object to be heated is under-heated or over-heated.

Conventionally, as a solution to this problem, a temperature sensing element is inserted into the object to be heated, the temperature of the object to be heated is directly detected, and the oscillation of the magnetron is controlled to control the heating of the object to be heated. methods are being used.

In the device having such a means, the object to be heated loses its shape,
This may cause damage by interfering with cooking.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a means for controlling the heating of an object to be heated, regardless of the type, weight, or initial temperature of the object, and which does not cause the object to lose its shape.

More specifically, it detects physical changes in the air flow passing through the cavity, controls the radio wave generation source using the signals, controls the heating of the object to be heated, and reliably constructs such means. , is the aim of the present invention.

Examples will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is the main body of the device, and 2 is a door attached to the main body 1 so as to be openable and closable.

The main body 1 has a cavity 3 as shown in FIG. 2, and a door 2 is disposed to close an entrance/exit (not shown) of the cavity 3 for the object to be heated.

In FIGS. 2 and 3, 4 is a magnetron that is a radio wave generation source.

Reference numeral 5 denotes a blower for cooling the magnetron 4. The blower 5 is surrounded by an air guide γ, and the air guide 7 is provided with a flow intake port 6.

8 is an exhaust air guide for cooling the magnetron 4, and 9 is an antenna cover that surrounds the antenna section of the magnetron 4.

The antenna force bar 9 is made of a dielectric material with low loss at high frequencies.

10 is a rotating saucer, and the heated object 1 is placed in the rotating saucer 10.
3 is placed, and the rotating prisoner drive motor 11 is used as the drive source,
The coupling piece 12 connects the rotary saucer drive motor 11
The driving force of is transmitted, and the rotary receiver 10
It is configured to perform rotational movement using the center of rotation as the center of rotation.

14 is an intake duct, and 15 is an intake opening formed in the cavity 3.

The wind entering the cavity 3 is introduced into the cavity 3 via the intake duct 14 and through the intake opening 15 .

Reference numeral 16 denotes an exhaust opening formed in the cavity 3, and the exhaust opening 16 is connected to the metal pipe 2 in order to prevent harmful radio waves.
1 is connected.

17 is an exhaust duct.

The air leaving the cavity 3 is exhausted through the exhaust opening 16 and through the exhaust duct 17 .

One end of the exhaust duct 17 is disposed near the blower intake port 6, so that the intake force of the floor 5 acts on the exhaust duct 17.

Reference numeral 18 denotes a detection element for detecting physical changes in the wind, that is, airflow, and in this embodiment, an element such as a thermistor that is sensitive to temperature changes in the airflow is used.

19 is an amplification means for amplifying the signal of the detection element 18;
20 is operated by the output generated from the thousand stages of amplification 19;
322, which is a control means for controlling the oscillation of the magnetron 4;
is a barrier provided in the path of the exhaust duct 17 that intersects with the flow of air.

The barrier 22 is provided with an opposing edge portion 23,
The small opening 23 communicates the cavity 3 with the exhaust duct 17, and is a group of small openings that are smaller than the exhaust opening 16.

Next, the operation of the above embodiment and the effects of each part will be explained.

Radio waves generated by the magnetron 4 are radiated into the cavity 3 and heat the object 13 to be heated.

The object to be heated 13 rotates together with the rotating tray 10 and is uniformly heated.

As the heating of the object to be heated 13 progresses, the object to be heated 13
The radiant heat radiated from increases.

This heat is transferred to the sensing element 18 by the wind passing through the cavity 3.

The detection element 18 generates a signal in response to a change in the radiant heat of the object 13 to be heated.

The signal generated from the sensing element 18 is amplified by the amplification stage 19 and transmitted to the control stage 20.

Therefore, when the object to be heated reaches a desired temperature, the control stage 20 is activated, the oscillation of the magnetron 4 is controlled, and the heating of the object to be heated is controlled.

The present embodiment operates as described above.

Incidentally, the first feature of this embodiment is that the heating of the object to be heated is not controlled by a timer.

Therefore, since it is not necessary to adjust the heating time, it becomes possible to control heating of the object to be heated to a desired temperature regardless of the type, weight, or initial temperature of the object to be heated.

The second feature is that the detection element 18 is not directly inserted into the object to be heated, but it is a so-called indirect detection method that detects the temperature change of the object to be heated, so the object to be heated does not lose its shape. be.

The third characteristic is the uniqueness of the wind path.

As shown in the embodiment, a barrier 22 intersecting the flow of the airflow is provided in the path of the airflow guide, ie, the exhaust duct 17, which communicates with the sensing element 18 portion.

The effect of adopting such a precaution is to alleviate the change in the detection element 18 in response to a sudden physical change in the airflow, and prevent malfunction or abnormality in the control circuit system due to the sudden change. It is possible to prevent the operation, for example, the chattering of the switch.

An example of a sudden physical change is the so-called bumping phenomenon, in which a heated object containing moisture suddenly releases water vapor along with bubbles when it suddenly reaches near the 5th point.

In addition to this bumping phenomenon, water vapor is also dissipated due to flickering.

By adopting such a configuration, it is possible to alleviate the so-called water vapor fluctuation phenomenon.

However, such a configuration is not without collateral damage.

When a barrier is provided in the airflow path, turbulence is generated in that area, causing turbulence in the airflow such as areas where the flow velocity is high and areas where it is slow.

For this reason, water vapor condenses in areas where the flow rate is slow, and the condensed water droplets may cause malfunction of the detection element 18 or deteriorate the insulation of the blower 5, which may eventually cause a failure.

For this kind of problem, as shown in the example, barrier 2
A possible solution is to provide an opening 23 facing the cavity 2 and communicating with the cavity 3 so that the water droplets can be returned to the cavity 3.

As described above, according to the present invention, the heating of the object to be heated can be controlled without deforming the object, regardless of the type of the object, weight or initial temperature, and the means for doing so can be reliably constructed. We can provide a high frequency heating device that can.

In addition, in the embodiment, a configuration was presented in which the oscillation of the mag-untron is controlled by capturing the temperature change of the airflow passing through the cavity, but the configuration is not necessarily limited to such a configuration.
For example, the idea of the present invention can also be applied to a structure in which the heating of the object to be heated is controlled by controlling the oscillation of a magnetron using other physical changes such as changes in the humidity of airflow due to water vapor generated from the object to be heated. Needless to say, it can be done.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a high-frequency heating device according to the present invention,
FIG. 2 is a schematic vertical cross-sectional view of the main part, and FIG. 3 is a schematic cross-sectional view of the main part. 3...Cavity, 4...Magnetron, 5
...Blower, 16...Exhaust opening, 1
7... Exhaust duct, 18... Detection element, 22... Barrier, 23... Small opening.

Claims (1)

[Claims] 1 has a cavity 3 for storing an object to be heated, has an opening through which the airflow passes, and has a detection element 18 near the outlet side of the airflow that detects a physical change in the airflow. In addition, an airflow guide is communicated with the sensing element 18 portion, and a barrier 22 that crosses the airflow is provided in the path of the airflow guide, and the airflow guide has an opening communicating with the cavity 3. A high-frequency heating device characterized in that a group of small openings 23 are provided facing the barrier 22.