JPS5920931B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency heating device that heats an object using radio wave energy.

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

A common configuration of such a high-frequency heating device is to supply radio waves emitted from a radio wave generation source such as a magnetron 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 is of composition. In the apparatus having such a configuration, the heating time of the object to be heated is usually controlled by timer means or the like. 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 undercooked or overcooked. Conventionally, as a solution to this problem, a temperature sensing element was inserted into the object to be heated, the temperature of the object to be heated was directly detected, and the oscillation of the magnetron was controlled to control the heating of the object. A method has been used. In the same apparatus having such a means, the object to be heated loses its shape, causing problems in cooking. Therefore, the present invention focuses on the types of objects to be heated,
It is an object of the present invention to provide a means for controlling the heating of an object to be heated, which is independent of weight and initial temperature and does not cause deformation of the object.

More specifically, the purpose is to detect physical changes in the air flow passing through the cavity, control the radio wave generation source using the signals, and control the heating of the object to be heated, and to reliably configure such means. There is an aim of the present invention. Examples will be described below with reference to the accompanying drawings. In Figure 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 so as to close an entrance (not shown) for a heated object in the cavity 3. In Figures 2 and 3, 4
is a magnetron that generates radio waves. 5 is a blower for cooling the magnetron 4, the blower 5 is surrounded by an air guide T, and the air guide 7 has a blower intake port 6.
It is equipped with

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 cover 9 is made of a dielectric material with low loss at high frequencies.
10 is a rotating saucer, and the rotating saucer 10 holds a heated object 13.
is mounted, the rotating saucer drive motor 11 is used as a driving source, the driving force of the rotating saucer drive motor 11 is transmitted through the coupling piece 12, and the rotating saucer 10 rotates around the rotation axis 0-0'. It is configured to perform exercise.

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. A metal pipe 21 communicates with the exhaust opening 16 in order to prevent harmful radio waves.

17 is an exhaust duct.

The wind leaving the cavity 3 is exhausted through the exhaust duct 11 via the exhaust opening 16 . One end of the exhaust duct 17 is disposed near the blower intake port 6 so that the intake force of the blower 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;
Reference numeral 20 denotes a control means that is operated by the output generated from the amplification means 19 and controls the oscillation of the magnetron 4.

Reference numeral 22 denotes a barrier provided in the path of the exhaust duct 17 near the intake port of the blower 5 so as to stand upward from the lower surface.

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 amount of heat radiated from the object to be heated 13 increases. This heat is transferred to the sensing element 1 by the wind passing through the cavity 3.
8. The sensing element 18 generates a signal in response to a change in the temperature of the object 13 to be heated. The signal generated from the sensing element 18 is amplified by the amplification means 19 and transmitted to the control means 20. Therefore, when the object to be heated reaches a desired temperature, the control means 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 the heating of the object to be heated to a desired temperature regardless of the type, weight, or initial temperature of the object. 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. It is.

The third characteristic is the uniqueness of the wind path. As shown in the embodiment, a blower 5 is installed in the path of the airflow guide, that is, the exhaust duct 17 that communicates with the sensing element 18.
A barrier 22 is provided in the vicinity of the air intake port 6 facing upward from the lower surface. The effect of having such a configuration is to prevent sudden physical changes in airflow.
The change in the detection element 18 is alleviated, and the control circuit system malfunctions or abnormally operates due to the sudden change.
For example, it is possible to prevent the chatter of a switch, etc. An example of a sudden physical change is the so-called bumping phenomenon, in which when a heated object containing moisture reaches near its boiling point, it suddenly releases water vapor along with bubbles. Furthermore, in addition to this bumping phenomenon, the so-called water vapor fluctuation phenomenon, in which water vapor is dissipated by flickering, can also be alleviated by using such a structure. However, such a configuration is not without collateral damage. When a barrier is placed in the airflow path, turbulence is generated in that area, causing turbulence in the airflow, such as where the flow velocity is high and where it is slow. For this reason,
In areas where the flow rate is slow, water vapor condenses, 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. To solve this kind of problem, as shown in the embodiment, a barrier 22 is provided in the vicinity of the blower intake port 6 so as to stand upward from the bottom surface, so that it is possible to prevent water droplets from moving toward the blower 5. can. As described above, according to the present invention, it is possible to control the heating of an object to be heated without causing the object to be heated to deform, regardless of the type of the object to be heated, its initial weight or initial temperature, and the means for doing so can be reliably configured. A high frequency heating device can be provided.

In the embodiment, a configuration was presented in which the oscillation of the magnetron was controlled by capturing the temperature change of the airflow passing through the cavity, but the present invention is not necessarily limited to such a configuration.
For example, the idea of the present invention may 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 applied.

[Brief explanation of the drawing]

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, 17... Exhaust duct, 18
...Detection element, 22...Barrier.

Claims (1)

[Claims] 1 An exhaust opening 16 is formed in the cavity 3 that houses the object to be heated, the exhaust opening is equipped with a detection element 18 that detects a physical change in the exhausted airflow, and one end of the exhaust duct 17 is connected to the exhaust opening. 16, and the other end is connected to the vicinity of the intake port 6 of the blower 5, and a barrier 22 is provided in the vicinity of the blower intake port in the path of the exhaust duct so as to stand upward from the lower surface. Features of high-frequency heating equipment.