JP2004220882A - Electromagnetic cooker with boiling detection function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic cooker with boiling detection function having high boiling detection performance by solving problems that container temperature of the electromagnetic cooker can not correctly controlled. <P>SOLUTION: Boiling detection is conducted by detecting the change of the quality of the material of the container 1 having Curie temperature by a detection means 5 for the material of the container. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker with a boiling detection function for automatically detecting boiling in a water heater.
[0002]
[Prior art]
In a conventional electromagnetic cooker with a boiling detection function, the temperature of a container is indirectly detected by a temperature sensor attached to the lower surface of a ceramic plate (for example, see Patent Document 1). The configuration will be described with reference to FIG. A container 101 is mounted on a ceramic plate 102 and is induction-heated by a high-frequency magnetic field generated by a heating coil 103 provided below the ceramic plate 102. 104 is a high-frequency power supply for supplying a high-frequency current to the induction heating coil 103; 105 is control means for controlling the high-frequency power supply; 106 is a temperature sensor attached to the lower surface of the ceramic plate 102, for detecting the temperature of the ceramic plate 102; Thus, the temperature of the container 101 is indirectly detected. The output of the temperature detecting element 106 is transmitted to the boiling detecting means 107 for automatically detecting the start of boiling, and the boiling detecting means 107 detects the boiling by utilizing the fact that the temperature rise curve of the temperature sensor 106 changes when boiling occurs. .
[0003]
[Patent Document 1]
JP-A-6-260271 (page 2, FIG. 11)
[0004]
[Problems to be solved by the invention]
However, in such a conventional electromagnetic cooker, it is difficult to accurately detect the timing of the boiling detection because the temperature of the container is detected via the ceramic plate. Further, there is a problem that the detection timing of boiling becomes earlier or later, for example, when foreign matter is caught between the container and the ceramic plate, the temperature detection accuracy becomes extremely poor.
[0005]
An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an electromagnetic cooker having a boiling detection function capable of detecting boiling with high accuracy.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the present invention uses a container having a Curie temperature as a container for boiling water, and the container material detecting means detects that the material of the container has changed when the temperature reaches the Curie temperature, and the container boils. This is to detect.
[0007]
As a result, boiling detection can be performed with high accuracy.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 of the present invention provides a heating coil, a high-frequency power supply for supplying a high-frequency current to the heating coil, control means for controlling the high-frequency power supply, and a curie to a predetermined temperature by a signal from the high-frequency power supply. It is provided with a container material detecting means for detecting a change in the material of a container having a temperature, and a menu selecting means for selecting a specific cooking menu from a plurality of cooking menus including a water heater function, and appropriately setting the Curie temperature. By doing so, if the temperature of the container becomes equal to or higher than the boiling point, a change in the material of the container material detecting means can be detected, and boiling can be detected.
[0009]
The invention according to claim 2 has a high-frequency output selecting means for instructing the control means to output a high-frequency power from a high-frequency power source and selecting the high-frequency output. When the water heating function is selected from a plurality of cooking menus, the high-frequency output is output. It has a selectable function, and it is possible to select an optimal power when changing the power depending on the size of the pot or the like.
[0010]
The invention according to claim 3 has a notifying unit, and when the container material detecting unit detects that the temperature of the container has reached a predetermined temperature, the unit performs the notifying, and notifies and notifies that boiling has occurred. It has the action of:
[0011]
According to a fourth aspect of the present invention, when the container material detecting means detects that the temperature of the container has reached a predetermined temperature, the control means changes the first output until the high-frequency output of the high-frequency power supply reaches the predetermined temperature. The second output is set to be low, and has the effect of reducing the power even after boiling to maintain the boiling.
[0012]
The invention according to claim 5 has time measuring means for measuring time, and notifies the first time after the container material detecting means detects that the temperature of the container has reached a predetermined temperature. The high-frequency output is further reduced from the second output to a third output, and has an effect of keeping the temperature after boiling.
[0013]
According to a sixth aspect of the present invention, the high-frequency output of the high-frequency power supply is set to zero after a second set time after the third output is further reduced from the second output, and the heat retention is continued for a long time. In this case, the heating is stopped for safety.
[0014]
According to a seventh aspect of the present invention, the notification is performed when the high-frequency output of the high-frequency power supply is reduced to zero after a second set time from when the third output is further lowered than the second output. This has the effect of notifying and notifying when the warming is finished.
[0015]
【Example】
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0016]
(Example 1)
In FIG. 1, reference numeral 1 denotes a container, the inside of which is made of a non-magnetic metal material 1a made of aluminum which is a good heat conductor having excellent heat conduction, and the outside of which is a magnetic material having a Curie temperature of a predetermined temperature (105 ° C. in this embodiment). It is integrally formed of the metal material 1b and has a self-temperature control function. The magnetic metal material 1b may be configured to cover the entire outside of the nonmagnetic metal deposit 1a, but it is sufficient that the magnetic metal material 1b is provided at least on the outer bottom surface of the nonmagnetic metal material 1a, as shown in the figure. Reference numeral 2 denotes a ceramic plate on which the container 1 is placed. Reference numeral 3 denotes a heating coil for heating the container 1, reference numeral 4 denotes a high-frequency power supply for supplying a high-frequency current to the heating coil 3, and reference numeral 5 denotes a container material detecting means for detecting whether the container 1 is a magnetic material or a non-magnetic material by a signal from the high-frequency power supply , 6 menu selection means for selecting a specific cooking menu from a plurality of cooking menus including a water heater function, 7 controls the high frequency output of the high frequency power supply 4 by inputting signals from the container material detection means 5 and the menu selection means 6 Control means.
[0017]
The operation of the electromagnetic cooker having the boiling detection function configured as described above will be described below.
[0018]
When water is put into the container 1 and the kettle is selected by the menu selection means 7 and the kettle is started, when the temperature of the bottom surface of the container 1 is low, the magnetic metal material 1b is a magnetic material. Judgment is made, and the high-frequency power supply 4 excites the heating coil 3 according to the heating signal from the control means 12. As a result, the alternating magnetic flux radiated from the heating coil 3 flows to the outer magnetic metal material 1b, but since the magnetic permeability is high, the eddy current induced by the alternating magnetic flux flows to the bottom side of the container 1 due to the skin effect of the high-frequency current. concentrate. For this reason, the alternating magnetic flux almost flows to the outer magnetic metal material 1b, and is not affected by the inner nonmagnetic metal material 1a. As a result, the eddy current intensively flows on the surface (bottom side of the pan) of the magnetic metal material 1b, the electric resistance of the container 1 becomes equivalently large, the Joule heat generated by the eddy current is large, and the container 1 is heated. (The high-frequency output at this time is 2 kW).
[0019]
When the heating is continued, the water in the container reaches the boiling point (100 ° C.) and starts boiling. However, the temperature of the magnetic material 1b of the container 1 rises to the boiling point or more due to the generation of bubbles due to the boiling. When the temperature of the magnetic material 1b reaches the Curie temperature of 105 ° C., the magnetic material 1b loses magnetism, so that the magnetic permeability decreases and the penetration depth of the eddy current (the depth from the surface until the surface current decreases to a constant rate). Deepens.
[0020]
As a result, an eddy current due to the alternating magnetic field also flows through the inner non-magnetic metal material 1a, and the eddy current flows through the entire cross-sectional area of the entire bottom side of the container 1 as a whole. Joule heat is small, and the calorific value of induction heating is small. As a result, the high frequency output of the high frequency power supply decreases. The container material detecting means 5 detects this change and outputs a signal to the control means 7. The control means 7 determines that the water in the container 1 has boiled, and outputs a signal to the high-frequency power supply 4, which stops supplying the high-frequency current to the heating coil 3.
[0021]
(Example 2)
Next, a second embodiment of the present invention will be described with reference to the drawings.
In FIG. 2, a high-frequency output selection means 8 is added to the first embodiment.
[0022]
The operation will be described below.
[0023]
Water is put into the container 1, the kettle is selected by the menu selection means 7, and then the high-frequency output is selected by the high-frequency output selection means 8. In this embodiment, the output can be selected from two outputs of 2 kW (strong) and 1 kW (weak). Normally (strong), when the pot is small or when the inner surface of the pot is subjected to fluorination, the fluorination is performed if the output is too high. Select (weak) if you are concerned. Subsequent operations are the same as in the first embodiment, and a description thereof will be omitted.
[0024]
(Example 3)
Next, a third embodiment of the present invention will be described with reference to the drawings.
In FIG. 3, a notification unit 9 is added to the first embodiment.
[0025]
The operation will be described below.
As described in the first embodiment, when boiling, the control means 7 outputs a signal to the high-frequency power supply 4, and the high-frequency power supply 4 stops supplying the high-frequency current to the heating coil 3. Sometimes, a notification is given by a piezoelectric buzzer to inform the user of the boiling.
[0026]
(Example 4)
Next, the operation of the fourth embodiment of the present invention will be described.
[0027]
In the first embodiment, when boiling, the control means 7 outputs a signal to the high-frequency power supply 4, and the high-frequency power supply 4 stops supplying the high-frequency current to the heating coil 3. Reduce output. In this embodiment, the high-frequency output, which was 2 kW (first output) before the detection of boiling, is changed to 300 W (second output) after the detection of boiling. As a result, since the hot water maintains the boiling, even if the hot water is used for a while after the detection of the boiling, the boiling water can be used.
[0028]
(Example 5)
Next, a fifth embodiment of the present invention will be described with reference to the drawings.
In FIG. 4, a notifying unit 9 and a time measuring unit 10 are added to the fourth embodiment.
[0029]
Next, the operation of the fifth embodiment of the present invention will be described.
[0030]
In the fourth embodiment, when boiling, the control means 7 outputs a signal to the high-frequency power supply 4, and the high-frequency power supply 4 suppresses the supply of the high-frequency current to the heating coil 3 and keeps 2 kW (first power) until the boiling is detected. The high-frequency output (output) was changed to 300 W (second output) after the detection of boiling. In the present embodiment, the time measuring means 10 starts measuring the time from the point of time when the second output is made, notifies the piezoelectric buzzer after a predetermined time (10 minutes in this embodiment), and outputs the high frequency output to the third output. And keep it warm. In this embodiment, the power is set to 100 W. As a result, even when hot water is used for a while after the detection of boiling, hot water kept warm can be used. In addition, even if it is desired to boil, it can be boiled in a short time because it is kept warm.
[0031]
(Example 6)
Next, the operation of the sixth embodiment of the present invention will be described.
[0032]
In contrast to the fifth embodiment, in the present embodiment, the high-frequency output of the high-frequency power supply 4 is set to zero after a second set time (1 hour in this embodiment) after the third output. As a result, the power is not left standing for a long time, and the power is not wasted.
[0033]
(Example 7)
Next, the operation of the seventh embodiment of the present invention will be described.
[0034]
In contrast to the sixth embodiment, this embodiment uses a piezoelectric buzzer when the high-frequency output of the high-frequency power supply 4 is reduced to zero after a second set time (1 hour in this embodiment) after the third output. To inform. As a result, the user can be notified of the end of the heat retention.
[0035]
【The invention's effect】
As is clear from the above description, the electromagnetic cooker with a boiling detection function of the present invention has a great practical value, such as being able to perform boiling detection with high accuracy by being combined with a dedicated container.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an electromagnetic cooker with a boiling detection function according to a first embodiment of the present invention; FIG. 2 is a configuration diagram of an electromagnetic cooker with a boiling detection function according to a second embodiment of the present invention; FIG. 4 is a configuration diagram of an electromagnetic cooker with a boiling detection function according to a third embodiment of the present invention. FIG. 4 is a configuration diagram of an electromagnetic cooker with a boiling detection function according to a fifth embodiment of the present invention. Configuration diagram of electromagnetic cooker with function [Description of symbols]
3 Heating coil 4 High frequency power supply 5 Container material detecting means 6 Menu selecting means 7 Control means 8 High frequency output selecting means 9 Notification means 10 Time measuring means Temperature detecting means

Claims (7)

A heating coil, a high-frequency power supply for supplying a high-frequency current to the heating coil, control means for controlling the high-frequency power supply, and a container material for detecting a change in the material of the container having a Curie temperature at a predetermined temperature by a signal from the high-frequency power supply An electromagnetic cooker with a boiling detection function, comprising: a detection means; and a menu selection means for selecting a specific cooking menu from a plurality of cooking menus including a water heating function. The control means includes high-frequency output selection means for indicating the strength of the high-frequency output of the high-frequency power supply and selecting the high-frequency output, and selects the high-frequency output when the water heating function is selected from a plurality of cooking menus. An electromagnetic cooker with a boiling detection function according to the item. 2. The electromagnetic cooking device with a water heater according to claim 1, further comprising a notifying unit, wherein the container material detecting unit notifies when the temperature of the container reaches a predetermined temperature. When the container material detecting means detects that the temperature of the container has reached a predetermined temperature, the control means changes the high frequency output of the high frequency power supply from a first output until the predetermined temperature to a second output lower than the predetermined temperature. Item 2. An electromagnetic cooker with a boiling detection function according to Item 1. The container material detecting unit has a time measuring unit for measuring time, and the container material detecting unit notifies the high-frequency output more than the second output, while notifying after a first set time from when detecting that the temperature of the container has reached a predetermined temperature. The electromagnetic cooker with a boiling detection function according to claim 4, wherein the third output is further reduced. The electromagnetic cooker with a boiling detection function according to claim 5, wherein the high-frequency output of the high-frequency power supply is set to zero after a second set time after the third output is further reduced from the second output. 7. The electromagnetic cooking with a boiling detection function according to claim 6, wherein the notification is performed when the high-frequency output of the high-frequency power source is reduced to zero after a second set time after the third output is further reduced from the second output. vessel.

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