JP4066199B2 - Cooking utensil and electromagnetic induction heating cooker equipped with the cooking utensil - Google Patents

Description

  The present invention relates to a cooking utensil and an electromagnetic induction heating cooker equipped with the cooking utensil.

  In an electromagnetic induction heating cooker, a high frequency magnetic field is generated and excited by a high frequency current supplied from an inverter circuit to induce eddy current, and Joule heat is generated by the resistance of the eddy current and the cooking utensil to cook. The bottom of the tool generates heat. Since the heat conduction performance of the cooking utensil has been improved by using a sintered body mainly composed of carbon instead of the magnetic metal material that is the base material of conventional cooking utensils, the cooking performance mainly of uniform heating is improved. At the same time, a fluororesin coating was applied to the pan surface to prevent the ingredients from sticking (for example, see Patent Document 1).

JP-A-9-75211 (6th page, FIG. 2)

  Since the electromagnetic induction heating cooker of Patent Document 1 is used by applying a coating such as a fluororesin to a sintered body mainly composed of carbon on a base material of a cooking tool, thermal conductivity, ease of excitation, It is possible to configure only a single type of material without using a clad material obtained by complexing a plurality of types of metals in consideration of corrosivity. On the other hand, the carbon material used has been subjected to a uniform and dense molding process to produce the cooking utensil, thereby increasing the hardness of the cooking utensil. For this reason, although the hardness of a cooking utensil will be raised and the intensity | strength with respect to a static force will become strong, the intensity | strength with respect to impacts, such as a fall and a collision, is not so strong, and there existed a problem that it was easy to break.

  The present invention has been made in order to solve the above-described problems, and uses a sintered body mainly composed of carbon having a high thermal conductivity, and is not easily damaged by an impact such as a drop or a collision. An object is to obtain a tool and an electromagnetic induction heating cooker using the cooker.

  The cooking utensil according to the present invention is a sintered body mainly composed of carbon particles, and is a molded article made of a base material containing pores by kneading with a liquid binder while mixing gas. It is characterized by being.

  Because the base material of the cooking utensil uses a sintered body of carbon material with high thermal conductivity and has a structure with pores inside the base material, the temperature of the cooking utensil rises uniformly in a short time during heating While ensuring improved cooking performance, the pores inside the substrate absorb and disperse the force that deforms the substrate when subjected to impacts such as dropping or collision of the substrate, making it difficult to break .

Embodiment 1 FIG.
1 is a longitudinal sectional view of an electromagnetic induction heating cooker according to Embodiment 1 of the present invention, FIG. 2 is an enlarged sectional view of a part of the inside of a cooking pan of the electromagnetic induction heating cooker shown in FIG. 1, and FIG. It is the microscope picture which image | photographed a part of cross section of the cooking pan shown in FIG.
As shown in FIGS. 1 and 2, the main body 1 of the electromagnetic induction heating cooker has a cooking pot storage portion 2 provided with a hole 2 a in the center of the bottom, and is fixed to the outer wall portion of the cooking pot storage portion 2. Is provided with a heating coil 3 for electromagnetic induction heating. This heating coil 3 is comprised by the 1st heating coil 3a provided in the outer bottom part of the cooking pot accommodating part 2, and the 2nd heating coil 3b provided from the outer bottom part to the corner part, and each coil 3a. , 3b are swirled spirally and connected in series so that a high-frequency current is supplied.

A temperature sensor 4 is provided through the hole 2a formed at the bottom center of the cooking pot storage unit 2, and is supported from below by a compression spring 4a. A cooking pot (cooking tool) 5 is detachably stored in the cooking pot storage section 2, and a temperature sensor 4 is pressure-bonded to the bottom of the cooking pot 5.
This cooking pan 5 uses a sintered body 5a having a carbon content of 90% or more as a base material, and the porosity of the base material is 5% to 15% and the width is about 200 μm inside the base material. It has a pore 5b.
A fluorine coating layer 5d made of a film having a thickness of about 40 μm is formed on the inner surface of the cooking pan 5, that is, the surface located on the side containing food or the like, whereby the carbon sintered body 5a is peeled off during cooking. There is no way. As shown in the micrograph of FIG. 3, the fluorine coating layer 5d covers the pores 5c having a width of about 200 μm that are opened in the inner surface portion of the sintered body 5a. A detailed cooking pot manufacturing method is described below.

  Coke, which is a high carbon content, is pulverized to 100 μm or less, and this is mixed with tar chips, which are liquid binders produced by melting at a high temperature. At this time, it is preferable to use a kneading apparatus similar to a rotating biaxial extrusion screw, such as a Banbury mixer capable of obtaining a high shearing force and uniform mixing. In addition, it is important that the ratio of coke to tar chips is about 2: 1, and a sufficiently viscous liquid can be secured during kneading at a high temperature.

  Next, pores are formed by blowing nitrogen gas during kneading. At this time, the apparent volume is increased to about 15 to 20%, and then kneading is continued for about 20 minutes to achieve uniform dispersion and refinement of the pores. The kneaded carbon material is sealed in a cylindrical mold, cooled until solidified, taken out, and then fired at a high temperature of 1000 ° C. or higher, preferably 3000 ° C., to sinter fine coke particles. During firing, a temperature rise and fall rate of about 2 ° C / Hr is secured so that the cylindrical molded product is not excessively deformed and the outer periphery is covered with fine coke powder for the purpose of blocking oxygen. Therefore, it is preferable to take care not to leave stress due to shrinkage during sintering inside.

  The fine pores contained in the cylindrical molded product are filled with nitrogen, which is an inert gas, so that when sintered at high temperatures, impact strength such as fine cracks generated by damage to the pore inner walls is obtained. Generation | occurrence | production of the defect to reduce can be suppressed. After that, impurities contained in the coke and tar pitch are scattered and the partition walls forming the fine pores can be communicated, so even if the cooking pot becomes hot and the air in the pores expands, it communicates. The expanded air is reliably discharged outside through the other pores. As a result, the inside of the pores can be prevented from becoming high pressure due to the expanded air, and a cooking pot that is difficult to break can be obtained.

  The sintered body obtained through the above steps can be formed into an arbitrary shape by cutting, and the cooking pot according to the present embodiment is secured.

  In the cooking pot 5, convex support portions 6 are formed at, for example, three locations of the flange portion formed above the storage portion 2, and are supported by the support portions 6. The cooking pan 5 is covered with an inner lid 7, and a lid packing 8, which is a sealing material, is disposed on the peripheral portion of the inner lid 7, and the lid packing 8 provides a sealing property between the cooking pot 5 and the flange portion. It is secured. The inner lid 7 is covered by an outer lid 9 connected by a locking member 10 and is supported by the main body 1 so as to be freely opened and closed. The inner lid 7 and the outer lid 9 are provided with a steam port 11 penetrating them, and the steam port 11 is constituted by a cooking pan inner valve 11a and an outer valve 11b. An operation display unit 12 is provided on a part of the outer lid 9.

  Next, the operation will be described. First, a predetermined amount of rice is put into the cooking pan 5, and then water corresponding to the amount of rice is added. Next, when the cooking pan 5 is stored in the cooking pan storage portion 2 and the outer lid 9 is closed, the lid packing 8 of the inner lid 7 is pressed against the flange portion of the cooking pan 5 and the cooking pan 5 is hermetically sealed. And the rice cooking process switch of the operation display part 12 is turned ON, and the rice cooking process is started.

  The first and second heating coils 3a and 3b are supplied with a high-frequency current from an inverter circuit (not shown) to generate a high-frequency magnetic field and cooked magnetically coupled to the first and second heating coils 3a and 3b. The surface of the pan 5 facing the heating coils 3 a and 3 b is excited, and an eddy current is induced on the bottom surface of the cooking pan 5. Joule heat is generated by the eddy current and the resistance of the cooking pan 5, and the bottom surface of the cooking pan 5 generates heat. Since the cooking pot 5 has a high resistivity of about 7.2 × 10 −7 or more, electromagnetic induction heating is possible. The cooking pan 5 made of carbon has higher heat conduction characteristics than the conventional cooking pan capable of electromagnetic induction heating in which a plurality of types of metals are laminated, so the temperature of the cooking pan 5 is uniform in a short time. As a result, the ingredients are heated uniformly and efficiently. In the above description, the heating coil 3 is divided into the first coil 3a and the second coil 3b. However, the heating coil 3 may be collectively installed from the outer bottom surface to the corner portion.

According to the first embodiment, the cooking pan 5 is composed of the sintered body 5a having a carbon content of 99% or more and has the pores 5b in the base material. Even if it receives, the force which deform | transforms a base material will be absorbed and an impact will disperse | distribute. For this reason, even if a strong external force is applied to the cooking pan 5, it is less likely to be damaged than when the base material is molded uniformly and densely. In this case, the strength against breakage is particularly strong when the porosity of the substrate is between 5% and 15%. In the cooking pan, the fluorine coating layer 5 d covers the pores 5 c opened in the inner surface portion of the sintered body 5 a, thereby preventing moisture from leaking from the inside of the cooking pan 5.
In the above description, the case where the fluorine coating layer 5d is formed on the inner surface of the cooking pan 5 has been shown. However, it may be formed on the outer surface, and in this case, the inner and outer surfaces of the cooking pan 5 may be formed on the cooking pan. Thus, it is possible to obtain an effect of protecting against the behavior such as wear that occurs during cleaning or the like (the same applies to the second and third embodiments).

  Using the inner pot of a jar rice cooker that is a cooking pot manufactured based on the present embodiment, from a clad material in which iron, which is a conventional magnetic metal, aluminum with high thermal conductivity, and stainless steel with excellent corrosion resistance are laminated. We compared rice cooking characteristics with the same shape inner pot. The same amount of water was put inside the kettle with the same input and time ensured, and the same jar rice cooker was used for heating under the rice cooking conditions, and the temperature change at that time was observed. The result is shown in FIG.

  As shown in FIG. 4, as a result of the temperature rise test up to 100 ° C., a clear difference was observed in the internal water storage temperature with respect to the same shape inner pot made of the conventional clad material. In the inner pot using the carbon agent according to the present embodiment, the Joule heat generated on the coil side surface is easily conducted in the thickness direction of the hook as compared with the inner pot of the same shape made of the conventional clad material. It was confirmed that the water stored in the inner pot could be quickly heated.

  In other words, the jar rice cooker equipped with the inner pot according to the present embodiment is sensitive to the inner surface portion of the pot rising to the input and rising, ensuring a higher rice cooking temperature and stable temperature holding. Was suggested.

  Moreover, the practical impact resistance of the inner hook was evaluated. For the inner pot A according to the present embodiment having fine pores by kneading in a gas-mixed state and the inner pot B having the same shape using a carbon material only in a mixed manner, 200 g on the side portion The falling ball impact strength expressed by the maximum height that can be withstood by dropping the steel ball was obtained. As a result, although the density of the inner hook B is 1.88 g / ml, the density of the inner hook A is 1.74 g / ml, and the falling ball impact strength is 40 cm of the inner pot B. On the other hand, the inner pot A was as strong as 55 cm, and it was found that it could withstand collisions of other tableware that could occur in practice.

Thus, according to the present embodiment, a cooking pan that is practically sufficient in strength and hard to break can be obtained.
Note that the cooking utensil according to the present invention is not limited to the cooking pan 5 described in the present embodiment, and for example, all kinds of utensils that can be used for cooking such as a frying pan and a grilled meat plate. Is the target.

Embodiment 2. FIG.
FIG. 5 is an enlarged cross-sectional view of a part of the inside of the cooking pan of the electromagnetic induction heating cooker according to Embodiment 2 of the present invention.
In the second embodiment, the pores 5c opened on the inner surface of the sintered body 5a are filled with aluminum 20.
Other configurations are substantially the same as those shown in the first embodiment, and thus description thereof is omitted.

  In order to manufacture the cooking pot 5 of the electromagnetic induction heating cooker configured as described above, a fine powder of carbon is extruded to form a sintered body 5a having a carbon content of 90% or more. During this extrusion molding, pressure and temperature are set so that pores 5b having a porosity of 5% to 15% and a width of about 200 μm are formed inside the substrate. After the sintered body 5a is formed in this way, fine aluminum powder having a particle size smaller than that of the pores 5b is filled in the pores 5c opened on the inner surface of the sintered body 5a, and heated at a temperature of 660 ° C. or higher. And melt. After that, a fluorine coating process is performed on the inner surface of the cooking pan 5 to form a fluorine coating layer 5d having a thickness of about 40 μm.

Since the melting point of the aluminum fine powder is lower than the firing temperature of the carbon constituting the sintered body 5a, the aluminum fine powder is melted in the pores 5c opened in the inner surface portion of the sintered body 5a. Held. For this reason, there is no air layer between the fluorine coating layer 5d and the sintered body 5a, and the adhesion is stronger compared to the apparent adhesion strength associated with peeling of the sintered carbon powder particles on the surface of the cooking pan. Since strength can be obtained, it is possible to prevent the fluorine coating layer 5d from being easily peeled off due to the peeling behavior due to the expansion and contraction of the air layer accompanying the temperature rise and cooling of the cooking pan 5 during cooking.
In other words, when the surface of the carbon material, which is a base material, is coated with a mixture of a heat-resistant resin and a fluororesin as a base treatment agent and the top surface thereof is coated with a fluororesin to prevent the carbon material from adhering, As long as the surface is treated, the tape peeling test peels off 1 to 5 times without performing the above treatment, but it does not come off even 20 times or more, and strong adhesiveness can be secured. .

Embodiment 3 FIG.
FIG. 6 is an enlarged cross-sectional view of a part of the inside of the cooking pan of the electromagnetic induction heating cooker according to Embodiment 3 of the present invention.
In the third embodiment, the fine powder filling the pores 5c is made of the same material as that of the sintered body 5a, and the fine carbon powder is placed in the pores 5c opened on the inner surface of the sintered body 5a. This is filled and fired again to constitute a carbon fired body 21.
Other configurations are substantially the same as those shown in the first embodiment, and a description thereof will be omitted.

  In order to manufacture the cooking pot 5 of the electromagnetic induction heating cooker configured as described above, a fine powder of carbon is extruded to form a sintered body 5a having a carbon content of 90% or more. During this extrusion molding, pressure and temperature are set so that pores 5b having a porosity of 5% to 15% and a width of about 200 μm are formed inside the substrate. After the sintered body 5a is formed in this way, fine powder of carbon having a particle diameter smaller than that of the pores 5b is filled in the pores 5c opened on the inner surface portion of the sintered body 5a, and again at a temperature of about 3000 ° C. A carbon fired body 21 is formed by heating and firing. After that, a fluorine coating process is performed on the inner surface of the cooking pan 5 to form a fluorine coating layer 5d having a thickness of about 40 μm.

  For this reason, since the air layer between the fluorine coating layer 5d and the sintered body 5a is reduced, there is no influence of the expansion and contraction of the air layer accompanying the temperature rise or cooling of the cooking pan 5 during cooking, and the fluorine coating layer 5d It is possible to prevent deterioration from the pore 5c portion. Thus, since the cooking pot 5 is comprised by the sintered body of carbon to the inner surface, the cooking pot 5 with high heat conductivity can be obtained.

  The fine carbon powder used for manufacturing the cooking pot 5 may be produced by polishing the inner surface of the sintered body 5a. In this case, the inner surface is polished after the sintered body 5a is formed. A process and a process of removing excess fine powder will be added.

It is a longitudinal cross-sectional view of the electromagnetic induction heating cooking appliance which concerns on Embodiment 1 of this invention. It is sectional drawing to which a part of inner side of the cooking pan of the electromagnetic induction heating cooking appliance shown in FIG. 1 was expanded. It is the microscope picture which image | photographed a part of cross section of the cooking pan shown in FIG. It is the figure which compared the rice cooking characteristic of the cooking pot which concerns on this Embodiment, and the cooking pot which consists of the conventional magnetic metal. It is sectional drawing to which a part of inner side of the cooking pot of the electromagnetic induction heating cooking appliance concerning Embodiment 2 of this invention was expanded. It is sectional drawing to which a part of cooking pot inner side of the electromagnetic induction heating cooking appliance concerning Embodiment 3 of this invention was expanded.

Explanation of symbols

5 Cooking pot, 5a sintered body, 5b pore, 5c pores opened on the inner surface of the sintered body, 5d fluorine coating layer, 20 aluminum, 21 carbon fired body.

Claims (6)

  A cooking tool, which is a sintered body mainly composed of carbon powder, and is a molded article made of a base material containing pores by kneading with a liquid binder while mixing gas.   2. The cooking tool according to claim 1, wherein fine powder having a smaller diameter than the fine pores and having a melting point lower than that of the base material is filled in the fine pores opened on the surface of the base material and melted or baked. .   The cooking utensil according to claim 1, wherein fine powders having a diameter smaller than the pores and made of the same material as that of the substrate are filled in the pores opened on the surface of the substrate and baked. .   The cooking tool according to claim 3, wherein the fine powder is produced by polishing the sintered body.   The cooking tool according to any one of claims 1 to 4, wherein a surface of the sintered body is coated with fluorine. An electromagnetic induction heating cooker comprising the cooking tool according to any one of claims 1 to 5.

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