JPH04220989A - Deep pan for induction heating cooking apparatus - Google Patents

Abstract

PURPOSE:To provide a deep pan solely devoted to an induction heating cooking apparatus equipped with self temp. controlling function, by adopting the constitution according to the invention as described hereunder. CONSTITUTION:A magnetic metal material 1b having a specific Curie point is bonded to that part of a deep pan made of non-magnetic material 1a which is induction heated by a heater coil 2. Thus the deep pan solely devoted to an induction heating cooking apparatus is produced in a consolidated structure. Accordingly various modes of temp. control to suit cookings can be made by the use of magnetic metal material 1b with different Curie point.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction cooker pot having a self-temperature control function.

0002

[Prior Art] An electromagnetic cooker, which is a typical type of induction heating cooker, has a heating coil placed under the top plate, and the lines of magnetic force generated by the heating coil cause the inside of the bottom surface of the induction cooking pot on the top plate to be heated. It creates eddy currents that generate heat.

Conventionally, pots for induction heating cookers have been made of magnetic metal materials (iron, SUS430 stainless steel), magnetic metal materials (iron, SUS430 stainless steel), and non-magnetic metal materials (aluminum, SUS304 stainless steel).
Pots made of cladding material (two-layer or multi-layer) of stainless steel are often used.

[0004] In such conventional pots, the temperature is controlled by a temperature detection means such as a thermistor installed on the back of the top plate, and safety is ensured in the event of abnormalities such as automatic temperature adjustment and cooking. There is.

[0005] Various cooking devices such as rice cookers and hot plates that use induction heating as a heat source are also being developed, but all of them use a thermistor or thermostat to detect the temperature of the pot, so essentially they are This is similar to the electromagnetic cooker described above.

[0006]

[Problems to be Solved by the Invention] However, in such conventional induction heating cooker pots, the thermal conductivity of the crystallized glass used in the top plate is low, so the actual temperature of the induction heating cooker pot is low. The temperature difference between the temperature and the temperature sensitive to the thermistor becomes large, the thermal response is poor, and it is difficult to control the temperature under abnormal usage conditions such as cooking, and pots made of metal can cause problems such as significant warping or deformation of the bottom surface. there were.

[0007] Also, in other induction heating cooking appliances, insufficient temperature detection accuracy due to the temperature distribution at the bottom of the pot has been an impediment to improving cooking performance and safety. The present invention is an attempt to solve the above-mentioned conventional problems, and is an attempt to provide a pot for an induction heating cooker having a self-temperature control function.

[0008]

[Means for Solving the Problems] In order to achieve the above object, a pot for an induction heating cooker (hereinafter referred to as an induction pot) of the present invention
This is achieved by integrating a magnetic metal material having a predetermined Curie temperature into at least a portion of the pan made of a non-magnetic material facing the heating coil.

[0009]

[Function] According to the above-described structure, the present invention provides an induction pot in which a magnetic metal material having a predetermined Curie temperature is arranged on the outside of a pot made of a non-magnetic material facing a heating coil. When the temperature of Concentrate on the side.

Therefore, most of the alternating magnetic flux flows through the magnetic metal material on the outside, and is not affected by the use of non-magnetic metal material on the inside.

As a result, the eddy current flows intensively on the surface of the outer magnetic metal material (bottom side of the induction pot), the electrical resistance of the induction pot becomes equivalently large, and the Joule heat generated by the eddy current increases. This greatly increases the amount of heat generated by induction heating.

On the other hand, above the Curie temperature, the magnetic metal material loses its magnetism, so its magnetic permeability decreases and the penetration depth of eddy currents (the depth from the surface until the surface current decreases to a constant rate) increases.

[0013] For this reason, the eddy current that was flowing only on the bottom surface of the magnetic metal material now flows inside the magnetic metal material (although it has lost its magnetism since it exceeds the Curie temperature), and as a result, Since the electrical resistance value is significantly reduced, Joule heat is significantly reduced.

[0014] To further explain the changes in heating operation step by step, when heating is started from room temperature, it heats with a large amount of heat until it reaches the Curie temperature, and as a result, the induction pot reaches the Curie temperature. Then, the induction pot itself automatically changes its characteristics and generates less heat.

[0015] Then, when the temperature of the induction pot decreases to below the Curie temperature, the outer magnetic metal material regains magnetism and resumes heating with a large amount of heat.

[0016] Here, if the Curie temperature of the outer magnetic metal material is selected to a desired set temperature, the pot itself can automatically control the amount of heat generated by the above-described operation.

Furthermore, if a non-magnetic metal material is selected as the non-magnetic material, the above-mentioned effect will be even more effective.

That is, until the magnetic metal material on the outside of the induction pot reaches the Curie temperature, the heating operation is similarly performed without being affected by the non-magnetic metal material on the inside. Eddy currents due to the alternating magnetic field also flow in the metal material, and as a whole, the equivalent electrical resistance further decreases due to the large cross-sectional area of the entire bottom of the induction pot, and the amount of heat generated by induction heating becomes extremely small.

[0019] Furthermore, if a material with lower electrical resistance is selected as the inner non-magnetic metal material than the outer magnetic metal material, the difference in electrical resistance before and after the Curie temperature will become even larger, making it possible to control the amount of heating more easily. You can make it bigger.

For these reasons, by setting the Curie temperature to the desired temperature, it becomes possible to control the temperature with high accuracy.

[0021] In particular, when using this induction pot as a pot that uses water or oil, the high temperature cooking temperature is 180 to 250°C.
A magnetic metal material with a Curie temperature of about 100% is optimal. This temperature can be freely set by adjusting the composition of the ingredients, so it can be selected appropriately depending on the cooking menu. For example, if the Curie temperature is set to 100°C, it is possible to create a kettle that automatically stops heating when the water boils.

In addition, as magnetic metal materials having a Curie temperature, nickel alloys and iron-chromium alloys are most suitable because the Curie temperature can be freely changed and the skin resistance that determines the calorific value is large. As for the metal material inside, aluminum, copper, etc. are optimal because they have excellent thermal conductivity and low electrical resistance.

[0023]Furthermore, as a method for integrating a magnetic metal material having a Curie temperature with a non-magnetic metal material, bonding using a brazing material may be used, but bonding using a hot press method is most suitable.

On the other hand, the part of the magnetic metal material having the Curie temperature to be integrated into the non-magnetic pot should be at least the part facing the heating coil that is concentric with the heating coil, and it may be expanded to any part beyond this point. There is no particular problem in terms of characteristics if they are integrated, but it can prevent the weight of the induction pot from increasing.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a pot for an induction heating cooker placed on a top plate.

In the figure, 1 is an induction cooking pot (induction pot) placed on the top plate 3 made of a heat-resistant insulator of an electromagnetic cooker, and the inside for storing food is a non-stick made of aluminum. It is made of magnetic metal material 1a.

Further, on the outside of the bottom surface of the pot body made of non-magnetic metal material 1a, at a position opposite to the disc-shaped heating coil 2 provided on the lower side of the top plate 3, a nickel film having a Curie temperature of 180 degrees, for example, is placed. A magnetic metal material 1b made of an alloy is integrated by hot pressing.

FIG. 2 is a plan view of the bottom of the induction pot 1 of FIG. 1, viewed from above. That is, the outermost periphery is the bottom surface of the pot body made of non-magnetic metal material 1a made of aluminum, and inside thereof, magnetic metal material 1b is formed in the shape of a disk. The heating coil 2 is shown as a donut-shaped disk as indicated by the broken line. Here, since the alternating magnetic field radiated from the heating coil 2 is concentric with the heating coil 2, heating efficiency is good if the magnetic metal material 1b is also concentric with the heating coil 2.

Next, in order to evaluate the induction pot 1 of the present invention, oil was poured into the induction pot 1, which was placed on the top plate 3 of a conventional electromagnetic cooker, and tempura was cooked. The state at this time will be explained according to the graph of FIG.

That is, at timing a, induction heating of the induction pot 1 filled with oil is started by the heating coil 2. The output P of induction heating at that time is 1200W. After that, the oil temperature A rises almost linearly because the oil is heated continuously with constant heating power.

When the induction pot temperature reaches the preset Curie temperature of 180° C. (point b), the induction pot 1 rapidly changes to a non-magnetic material, and the induction heating output P decreases to 250W. The output value when it decreases (in this case, 250
W) can be varied depending on the material, thickness, shape, etc. of the magnetic metal material 1b.

After the induction pot 1 reaches the Curie temperature, the heat power decreases significantly, so the oil temperature A gradually decreases to 175°C (point c).
continues to decline. At this time, the magnetic metal material 1b restores its magnetism again, so the thermal power (output P) automatically rises to 1200W again, and the oil temperature A rises to 180°C, the Curie temperature, at rest.
(point c to point d).

[0033] Even if food such as tempura is put into the oil and the oil temperature A in the induction pot 1 drops to 175°C, the heat power is automatically turned on and off in the same way to keep the oil temperature A constant. .

As described above, the induction heating cooker pot 1 of the present invention
It has a self-temperature control function and can be expected to have significant effects such as improving cooking performance and safety against oil ignition.

Next, another embodiment will be explained with reference to FIG. The magnetic metal material 1B is injected into the bottom of the pottery container 1A and is integrally formed into an induction cooking pot (induction pot) 1.
It constitutes 0. Here, the magnetic metal material 1B layer protrudes from the surface of the ceramic container 1A and is in contact with the surface of the top plate 3. For this reason, even if boiled water or water adheres to the bottom of the induction pot 10, it will enter between the top plate 3 and the ceramic container 1A, so the induction pot
It rides on a water film and does not slip, making it extremely easy to use.

In the embodiments of the present invention, aluminum was used as the metal material for the pot body made of a non-magnetic material on the inside for storing food, but the metal material is not limited to this, and SUS304 type metal material was used. Metal materials such as stainless steel and copper may be used, and non-metallic materials other than ceramics such as glass may be used as long as they do not have magnetism.

Further, although a nickel alloy was used as the magnetic metal material 1b having the Curie temperature, the material is not limited to this, and may be appropriately selected depending on the set temperature, mechanical strength, workability, etc., including the materials explained in the operation section. be able to.

Furthermore, although 180 degrees has been explained as the Curie temperature, it is not limited to this temperature in particular, and may be selected as a desired temperature required for cooking, including the contents explained in the operation section.

[0039] Above, the explanation has mainly been given to an electromagnetic cooker having the top plate 3, but the same applies to all other cookers to which induction heating is applied.

[0040]

[Effects of the Invention] As is clear from the above description, the induction cooking pot of the present invention has the following effects.

(1) Since heating is performed at the maximum output until the set temperature is reached, the start-up time (preheating time) can be minimized.

(2) Since induction heating is used, there is no thermal resistance due to the heat capacity of the pot. Therefore, there is no overshoot in the pan temperature after reaching the set temperature.

(3) Even if the temperature of the pot suddenly drops due to the addition of food, etc., heating at the maximum heating power is automatically started without any time delay, and the temperature accuracy with respect to the set temperature is extremely high.

(4) Since it does not depend on the temperature detection accuracy of the detector installed in the electromagnetic cooker body, the combination of the pot and the main body is free (even if the model of the electromagnetic cooker body is changed, the temperature accuracy remains constant). can get).

(5) By making the magnetic metal material protrude from the non-magnetic material surface of the pot, it is possible to prevent the pot from slipping on the top plate during cooking.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an induction cooking pot according to an embodiment of the present invention placed on a top plate.

[Figure 2] A plan view showing the relationship between the bottom surface of the induction cooking pot and the heating coil.

[Figure 3] Diagram explaining the operation when the pot is used in an electromagnetic cooker

[Fig. 4] A cross-sectional view of another embodiment of the induction cooking pot placed on the top plate.

[Explanation of symbols]

1,10 Pot for induction heating cooker 1a, 1A
Non-magnetic material 1b, 1B Magnetic metal material

Claims (2)

[Claims] 1. A magnetic metal material having a predetermined Curie temperature is integrally formed on a portion of a pan made of a non-magnetic material that is heated by induction, and the magnetic metal material is formed at least in a portion facing a heating coil that induction heats the pan. An induction heating cooker pot formed substantially concentrically with the heating coil. 2. The induction heating cooking method according to claim 1, wherein the magnetic metal material is formed substantially concentrically with the heating coil at least in a portion facing the heating coil for induction heating the pot, and protrudes from the surface of the non-magnetic material. A skillful pot.