JP3733892B2 - Electromagnetic cooker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an infrared temperature sensor that measures temperature using infrared rays, and more particularly to an infrared temperature sensor that is used for temperature control of an electromagnetic cooker.
[0002]
[Prior art]
For example, in a cooking utensil used for heating food such as an electromagnetic cooker, how to accurately measure the cooking temperature is an important issue.
Regarding the temperature measurement of the cooking device, there are roughly two types, a contact type and a non-contact type, both of which are disclosed in, for example, Japanese Patent Laid-Open No. 8-306483. In this case, the temperature sensitive part is made of aluminum nitride ceramic, etc., in order to eliminate the detection time delay for the temperature change of the heating dish and to ensure the contact between the detection part and the heating dish when the heating dish is a turntable method. A contact-type temperature sensor is described which is made of a high thermal conductive dielectric material and is integrated with a drive shaft for rotating the heating dish to measure the temperature of the heating dish.
In addition, in order to solve the problem of ensuring contactability and sensor durability, and to measure the temperature with high response speed, the non-contact is installed at a position where the bottom of the heating pan is desired obliquely upward from the hole provided in the bottom wall of the heating chamber. A cooking device that detects the temperature of the heating dish with an infrared sensor of a mold is also disclosed at the same time.
[0003]
However, in the non-contact type temperature sensor using the infrared of the above-mentioned document, a flange is provided to prevent leakage of radio waves, and the detection hole and the detection window of the infrared sensor are not on the same vertical line. Since there is a hole through which the air passes, it is not possible to completely prevent damage to the internal equipment, contamination, and a decrease in mechanical strength due to radio wave leakage or foreign matter falling from the hole.
[0004]
An example of an electromagnetic cooker that detects the temperature using an infrared sensor without opening an infrared detection hole is disclosed in Japanese Utility Model Publication No. 61-194988. The top plate is formed of a material that transmits infrared rays, and an infrared detection sensor that detects infrared rays emitted from a pan as a heated object placed on the top surface of the top plate is disposed below the top plate. It is intended to detect the temperature of the pan by detecting infrared rays from the pan.
[0005]
However, when the top plate is formed so that the infrared transmittance of the entire top plate is uniform as in the present invention, the top plate often becomes nearly transparent when the infrared transmittance is increased, and the internal device is transparent. If the top plate is covered with an opaque coating or a colorant is added to form a top plate to improve the concealment, the infrared transmittance will be lowered and accurate. There arises a problem that the temperature measurement may be hindered.
In view of this, an invention in which a part of the top plate is not colored or replaced with an infrared transmitting body to provide a high infrared transmitting portion for more accurate temperature detection is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-284238 and actual implementation. This is proposed in Japanese Patent Application Laid-Open No. 62-14687.
[0006]
[Problems to be solved by the invention]
However, all of the above-mentioned inventions, regardless of whether there is a difference between direct measurement with a hole or measurement through a top plate or an infrared transmission part provided on the top plate, The temperature is measured by directly detecting the infrared rays radiated from a heated pan or pan that is a heated object.
[0007]
Therefore, it has been difficult to measure the exact temperature of the heated object itself. This is because if the temperature of the heated object is T and the infrared emissivity is ε, the temperature of the heated object is measured as T × ε when an infrared sensor is used.
[0008]
When adjusting the temperature, it is only necessary to correct the emissivity ε. However, since the emissivity ε differs depending on the material of the object to be heated, for example, when a different kind of pan is used, the accurate temperature Cannot be measured.
[0009]
The present invention has been devised to solve such problems, and is used in, for example, an electromagnetic cooker that performs temperature control, and measures the temperature of a target heated object quickly and accurately regardless of the type of the heated object. It is an object of the present invention to provide a non-contact type infrared temperature sensor having a structure that can withstand dirt and the like during cooking, does not impair mechanical strength, and does not damage internal equipment.
Another object of the present invention is to provide an electromagnetic cooker that performs temperature control using this infrared temperature sensor.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an electromagnetic cooker of the present invention is an electromagnetic cooker that heats an object to be heated by an induction heating source, the translucent heat-resistant member on which the object to be heated is placed, Heat from the heated object placed on the translucent heat-resistant member is transmitted, and a black body material layer that emits infrared rays according to the temperature of the heated object, and the black body material layer that is radiated from the black body material layer An infrared detector that detects infrared rays and outputs a temperature signal, the infrared detector is radiated from the black body material layer and detects the infrared rays that pass through the translucent heat-resistant member, The black body material layer is opposed to the translucent heat-resistant member.
[0011]
The black body material layer may be formed by coating the surface of the translucent heat resistant member, preferably with a substance having an infrared emissivity of 0.95 or more. A part or the whole may be preferably formed by containing a substance having an infrared emissivity of 0.95 or more at a content that does not allow infrared rays to pass through.
[0012]
The translucent heat-resistant member preferably transmits infrared light having a wavelength of at least 5 μm on the long wave side in order to improve the accuracy of temperature measurement. Furthermore, the black body material layer may have a protective layer made of the same material as the light-transmissive heat-resistant member.
[0014]
According to the present invention, the heat from the object to be measured or the heated object is first transferred to the black body material layer. Since the black body material layer has a constant infrared emissivity, the infrared light emitted from the black body material layer is detected by an infrared detector through a translucent heat-resistant member that transmits infrared light, so that the object to be measured or the object to be heated High-accuracy temperature measurement is possible regardless of the material.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described by taking an electromagnetic cooker as an example with reference to the accompanying drawings.
[0016]
1st Embodiment Fig.1 (a) is the schematic diagram which showed one Embodiment of the electromagnetic cooker using the infrared type temperature sensor which concerns on this invention.
The electromagnetic cooker 10a shown in the figure has an infrared detector 3 installed on an induction heating source 4 and a translucent heat-resistant member 2 on which the heated object 1 is placed.
[0017]
The surface of one side of the translucent heat-resistant member 2 is coated with a substance having an infrared emissivity as high as 0.95 or more to form a black body material layer 5.
The electromagnetic cooker 10 of this embodiment uses, for example, a magnetic force generating coil as the induction heating source 4, thereby generating a magnetic field, and this magnetic field generates Joule heat of induction current to the heated object 1 formed of a magnetic material. By generating it, the heated object 1 placed on the translucent heat-resistant member 2 and the food in it are heated.
[0018]
The object 1 to be heated is, for example, a pan formed of a magnetic material such as iron, iron enamel, or stainless steel. When these are heated by the Joule heat of the induction current of the magnetic field, the heat is transferred to the black body material layer 5. A black body is an object that completely absorbs radiation of all wavelengths, but the black body material layer 5 is a substance having a high infrared absorptivity and emissivity of preferably 0.95 or higher (hereinafter referred to as this). It may be formed of black body material). When the black body material layer 5 is warmed by the heat transferred from the object 1 to be heated, infrared rays having different wavelength spectrum biases depending on the temperature are emitted. The emitted infrared light is detected by the infrared detector 3 after passing through the translucent heat-resistant member 2.
[0019]
In conventional electromagnetic cookers that do not have the black body material layer 5, infrared rays emitted from the heated object 1 pass through the translucent heat-resistant member 2 as they are and are detected by the infrared detector 3.
Here, if the infrared emissivity of the heated object 1 at the temperature T is ε and the infrared transmittance of the translucent heat-resistant member 2 is α, the detected temperature of the heated object 1 is T × ε × α. If the material of the object to be heated 1 is different and the emissivity ε changes, the temperature cannot be measured accurately.
[0020]
On the other hand, when the black body material layer 5 is present as in the present embodiment, the black body material layer 5 has substantially the same temperature T as the heated object 1 due to heat transfer, and the emissivity is constant at this temperature T. The infrared rays radiated from the black body material layer 5 pass through the translucent heat-resistant member 2 and are detected.
Accordingly, assuming that the emissivity of the black body material is 1, for example, the detected temperature of the heated object 1 is T × α, and only the infrared transmittance of the translucent heat-resistant member 2 is corrected. Thus, accurate and highly accurate temperature measurement can be performed without being affected by the difference in the material of the heated object 1, that is, the emissivity.
[0021]
As infrared detectors, quantum photoconductive sensors and photovoltaic sensors, thermal thermopiles, bolometers, pyroelectric sensors, and the like are known, and any of these can be applied.
The material of the translucent heat-resistant member 2 needs to efficiently transmit infrared light and a magnetic field for induction heating. Moreover, since it uses for cooking, it is desirable to have the heat resistance to at least 200 degreeC. Accordingly, a glass material (for example, quartz sapphire) that transmits infrared light having a wavelength of at least 5 μm on the long wave side is preferably used.
Also, the infrared detector needs to have heat resistance according to the use situation.
[0022]
To describe the configuration example of the infrared temperature sensor of the first embodiment in more detail, a thermopile (heat-resistant temperature 100 ° C.) is used as the infrared detector 3, and the thermopile is shown in FIG. Thus, it installs in the inside of the electromagnetic cooker of translucent heat-resistant member 2 lower part as a table. The infrared detection section of the thermopile faces the bottom surface portion of the heated object 1 set at the center of the table, and transmits infrared rays radiated from the black body material layer 5 in a non-contact manner through the translucent heat-resistant member 2. And the temperature of the heated object 1 is detected.
[0023]
As the black body material, for example, a black body spray made by HORIBA, a trade name ES1-S made by OMRON, or the like is used. In consideration of heat transfer coefficient, temperature measurement accuracy, durability, etc., the black body material layer is preferably coated on the surface of the translucent heat-resistant member 2 with a thickness of about 0.2 mm. 5 is formed. The coating method may be, for example, spraying a black body material or attaching a heat-resistant film containing the black body material.
By making the black body material into a thin coating in this way, it is possible to configure a sensor that has a simple structure and has good followability to temperature changes.
[0024]
In order to improve the durability of the black body material coating, a coagulant or curing agent may be mixed in the black body material forming the coating, but the thickness is sufficient to prevent temperature measurement on the coating. Further providing the protective layer 6 is simple and highly effective for protecting the coating.
As the protective layer 6, it is easy to use the same material as that of the translucent heat-resistant member 2 in a laminated manner. The schematic diagram of the electromagnetic cooker 10b which has the protective layer 6 is shown by FIG.1 (b).
[0025]
1 (a) and 1 (b), the infrared detector 3 is mounted on the induction heating source 4. However, when the induction heating source is in the shape of a ring having a hole in the center, infrared detection is performed. It is good also as a structure which embeds the vessel | 3 in an induction heating source.
[0026]
According to the present embodiment, it is possible to measure the temperature accurately and accurately with a simple structure and no delay in tracking the temperature change. In addition, since infrared rays are detected by contact, it is not necessary to make a hole for detection in the light-transmissive heat-resistant member 2 that is a table, and the infrared detector can be disposed inside the cooker. It is possible to construct a temperature sensor that is resistant to dirt and the like and does not cause damage to internal equipment.
[0027]
Second embodiment Fig. 2 is a schematic view showing another embodiment of an electromagnetic cooker using an infrared temperature sensor according to the present invention.
The electromagnetic cooker 20 of the second embodiment is the same as the electromagnetic cooker 10 (a) of the first embodiment except for the structure of the black body material layer. Therefore, the description of the same part is omitted as appropriate.
[0028]
In the second embodiment, a planar layered black in which a predetermined amount of a substance (black body material) having an infrared emissivity of 0.95 or more is contained in part or all of the translucent heat-resistant member 2. A body material layer 50 is formed.
Also in this case, heat from the heated object 1 is transmitted to the black body material layer 50, and infrared rays from the black body material layer 50 that are radiated uniformly regardless of the material of the heated object 1 are detected. The temperature of the heated object 1 is measured.
[0029]
The black body material layer 50 may be configured to be sandwiched between two translucent heat-resistant members 2, but in order to accelerate heat transfer from the object to be heated 1 and improve followability to temperature changes, FIG. It is desirable to arrange it as close to the heated object 1 as possible.
[0030]
The black body material layer 50 may have a laminated structure as a member different from the translucent heat resistant member 2 or may be formed integrally with the translucent heat resistant member.
Further, the translucent heat-resistant member 2 may be evenly incorporated with a black body material so as to serve as both the translucent heat-resistant member and the black body material layer.
[0031]
The base containing the black body material may be a glass material made of the same material as the translucent heat-resistant member 2 or a different material. However, the content rate of the black body material is required so that at least infrared rays emitted from the heated object 1 are not transmitted as they are.
[0032]
According to the second embodiment, since the black body material layer 50 is formed by incorporating a black body material into, for example, a glass material, the black body material layer is superior in durability compared to the first embodiment. Can be obtained.
[0033]
Deformation The present invention is not limited to an electromagnetic cooker, but is also used as an infrared temperature sensor that can accurately measure the temperature of a temperature measurement target that generates heat regardless of the emissivity of the measurement target. be able to.
FIG. 3 and FIG. 4 show schematic views of this modification of the present invention. FIGS. 3A and 3B are modifications of the first embodiment of FIGS. 1A and 1B, and FIG. 4 is a modification of the second embodiment of FIG.
[0034]
3 and 4, since the temperature measurement object 100 generates heat by itself, the induction heating source 4 for heating is not shown, and the translucent heat resistant member 2 and the translucent heat resistant member are not shown. On one side of 2, temperature measurement is performed with the black body material layers 5, 50 disposed at a position where the temperature of the temperature measurement object 100 is directly or indirectly measured through the protective layer 6 and the translucent heat-resistant member 2. The infrared detector 3 is disposed at a position facing the object 100. Heat is transmitted from the temperature measurement object 100 to the black body material layers 5, 50, and the temperature measurement mechanism in which the radiant heat from the black body material layers 5, 50 is detected by the infrared detector 3, the translucent heat resistant member 2, Since the black body material layers 5 and 50, the material and forming method of the protective layer 6, the type of the infrared detector 3, and the like are the same as those in the first and second embodiments, detailed descriptions thereof are omitted.
[0035]
According to this embodiment, it is possible to obtain an infrared temperature sensor that is more accurate and versatile than conventional infrared temperature sensors that do not have a black body material layer.
[0036]
In addition, said embodiment is only an example for demonstrating this invention, for example, the positional relationship of the infrared detector 3 and the induction heating source 4, the material of the translucent heat-resistant member 2, etc. are claimed by this invention. Various changes can be made within the range.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to quickly and accurately measure the temperature regardless of the difference in the infrared emissivity of the object to be heated, and the performance does not deteriorate due to dirt during cooking, An electromagnetic cooker having a structure in which mechanical strength is not impaired and internal equipment is not damaged can be provided.
It is also possible to provide an infrared temperature sensor that can quickly and accurately measure the temperature of a general measurement target that generates heat regardless of the difference in the emissivity of the infrared of the temperature measurement target.
[Brief description of the drawings]
FIG. 1 (a) is a schematic diagram showing the structure of a first embodiment of an electromagnetic cooker using an infrared temperature sensor according to the present invention, and FIG. 1 (b) shows a protective layer. It is the schematic diagram which showed the structure of the electromagnetic cooker of Fig.1 (a) which has.
FIG. 2 is a schematic diagram showing the structure of a second embodiment of an electromagnetic cooker using an infrared temperature sensor according to the present invention.
FIGS. 3A and 3B are schematic views showing the structure of an infrared temperature sensor which is a modification of the first embodiment of the present invention.
FIG. 4 is a schematic diagram showing the structure of an infrared temperature sensor which is a modification of the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heated object 2 ... Translucent heat-resistant member 3 ... Infrared detector 4 ... Induction heating source (magnetic force generation coil)
5, 50 ... Black body material layer 6 ... Protective layer 100 ... Temperature measurement object

Claims (5)

An electromagnetic cooker that heats an object to be heated by an induction heating source,
A translucent heat-resistant member on which the heated object is placed;
Heat from the heated object placed on the translucent heat-resistant member is transmitted, and a black body material layer that emits infrared rays according to the temperature of the heated object;
An infrared detector that detects the infrared radiation emitted from the black body material layer and outputs a temperature signal;
The infrared detector is opposed to the black body material layer with the translucent heat-resistant member interposed therebetween so as to detect the infrared light emitted from the black body material layer and transmitted through the translucent heat-resistant member. Have
Electromagnetic cooker. The electromagnetic cooker according to claim 1, wherein the black body material layer is formed by coating the surface of the translucent heat-resistant member with a substance having an infrared emissivity of 0.95 or more . The black body material layer is formed by containing a substance having an infrared emissivity of 0.95 or more in a part or the whole of the translucent heat-resistant member at a content rate that does not transmit infrared rays as it is. The electromagnetic cooker according to claim 1 . The electromagnetic cooker according to any one of claims 1 to 3, wherein the translucent member is made of quartz glass or sapphire that transmits infrared light having a wavelength of at least 5 µm on the long wave side . The electromagnetic cooker according to any one of claims 1 to 4, further comprising a protective layer formed on the surface of the black body material layer with the same material as the light-transmissive heat-resistant member .

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