JP5927422B2 - rice cooker - Google Patents

Description

  The present invention relates to a pan used in an electromagnetic induction heating rice cooker.

  Conventionally, rice cooker pans that are widely available to the general public are manufactured using aluminum, stainless steel, titanium, iron, or a combination of these as a base material.

  In particular, in a pan used in an electromagnetic induction heating rice cooker, a magnetic metal such as ferritic stainless steel is arranged on the outer layer of the pan base material, and aluminum is laminated on the inner side, or in some cases, stainless steel is further formed on the inner surface. There are some that are laminated.

  As a characteristic of electromagnetic induction heating, a material having a high relative permeability has higher heat generation due to electromagnetic induction, so a magnetic metal such as ferritic stainless steel is often used for the outer layer of the pan, and the inner layer of the pan is also used. Aluminum having a high thermal conductivity is often used for the purpose of performing heat diffusion quickly and uniformly heating the food.

  In addition, in recent years, as a pot for an electromagnetic induction heating type rice cooker, in addition to using a metal as a base material, a base material made of a carbon material or ceramic is used as a base material. Some of them are compatible.

  Furthermore, these metal rice cooker pans are usually treated with a fluororesin coat on the inner surface to prevent the sticking of cooked rice, which improves the non-stickiness of rice. Yes.

  The fluororesin coat to be treated on the inner surface of the pan is usually from one layer to two or three layers, but has good non-stickiness, high durability and good appearance. From the viewpoint of obtaining, it is preferable that the fluororesin coat has two or more layers.

  In an electromagnetic induction heating rice cooker, it has been mentioned as a conventional problem that the exotherm of the pan is further improved, and as a means of improving the exotherm from the material side of the pan, a material with high permeability is used, or a unique It is an effective means to use a material having a high resistance value.

  From these viewpoints, ferritic stainless steel represented by SUS430, etc., has been often used as the magnetic metal in the heat generating layer of the electromagnetic induction heating type pan. In addition, there were an example using an iron-based alloy such as permalloy and an example in which copper plating was applied to the outer surface of the magnetic metal layer.

  However, in these materials, the specific resistance value and the relative permeability, which are factors that determine the electromagnetic induction heating characteristics, are variable factors during the molding process, but are stable as the material-specific factors after molding to the pan. However, there was a limit to improving the heat generation from the material side.

  Moreover, in rice cookers, improving the taste of rice is a big challenge. Conventionally, in rice cooker pots, the thickness of the base material is increased in order to distribute heat uniformly, and the base material is multi-layered. There was an example of laminating.

  However, from the viewpoint of improving the taste of cooked rice, it is also one of the important conditions to make the pan thicker or multi-layered to make the heat around uniform, but apart from that, It is also an important condition in terms of improving the taste that the heat generated in the magnetic metal layer is transferred to the pan without being lost.

  As a conventional example, there is one in which a heat insulating layer is provided on the outer surface of the pan (for example, Patent Documents 1 and 2), but it is difficult to improve the taste by simply providing the heat insulating layer on the outer surface of the pan. In the case of comprising, the heat radiation due to the far infrared radiation from the resin is increased, and there is a problem that the taste and the heat retaining property are impaired.

JP-A-10-211091 JP-A-11-56599

  The object of the present invention is to solve these conventional problems, and to improve the taste of rice cooked with an electromagnetic induction heating rice cooker by controlling the heat insulation of the pan for each part of the pan. .

  In order to achieve the above object, the present invention uses a base metal used in a pan for an electromagnetic induction heating rice cooker as a multi-layer metal, the base metal of the outermost layer is composed of a magnetic metal, and the surface of the magnetic metal A heat insulating layer is provided, and the heat insulating layer has a thermal conductivity of 0.3 W / m / k or less and has a configuration in which the heat insulating property is increased from the bottom of the pan to the side of the pan, and the heat insulating layer is heat reflective. The pan is characterized by having a layer as the outermost layer.

  Thereby, the heat generated in the magnetic metal layer is not easily escaped from the pan by the heat insulating layer, and the heat reflection layer keeps the far-infrared emissivity low, so that the heat is further difficult to escape.

  Moreover, in this invention, since it has the structure which heat insulation becomes high toward a pan side surface from a pan bottom, it has the structure which is hard to escape heat to the upper part of a pan.

  The pan of the electromagnetic induction heating rice cooker of the present invention can be appropriately controlled for each part of the pan due to the combined effect of the above-described heat insulating layer and heat reflecting layer, and thus occurs during rice cooking or heat retention. Since the heat is difficult to escape at the upper part of the pan and relatively easy to escape at the lower part of the pan, it can be ideally heated and the taste of the cooked rice can be improved.

Sectional drawing of the rice cooker which comprised the pot for rice cookers in embodiment of this invention The schematic diagram of the pan for rice cookers in embodiment of this invention Detailed cross-sectional schematic diagram of pan in the embodiment of the present invention The figure which shows the relationship between the addition amount of the additive for every part of the pan in embodiment of this invention, and a far-infrared emissivity

  1st invention makes a metal a base material, the metal of the base-material outer surface is comprised with a magnetic metal, provided the heat insulation layer whose heat conductivity is 0.3 W / m / k or less on the surface of the said magnetic metal, the said The heat insulating layer has a configuration in which the heat insulating property is increased from the bottom of the pan toward the side of the pan, and the upper layer is a rice cooker including a pan having a heat reflecting layer.

  More specifically, the base material of the pan is a multilayer metal such as a clad material obtained by joining a heat conductive metal such as aluminum and a ferritic stainless steel that is a magnetic metal having excellent electromagnetic induction heating characteristics. Then, the outer surface of the pan obtained by molding this, that is, the surface of the magnetic metal layer is subjected to a surface roughening treatment by shot blasting with alumina particles or the like so that the surface roughness Ra becomes 0.5 to 5 μm. It is desirable.

  Next, a heat insulating layer is formed on the surface of the magnetic metal layer. Preferably, a heat insulating layer having a thermal conductivity of 0.3 W / m / k or less is provided.

  Examples of the material constituting the heat insulating layer include fluorine resin, polyethersulfone, epoxy resin, silicone resin, and modified resins thereof. In order to further reduce the thermal conductivity, hollow glass beads, hollow ceramics are used. Fillers that reduce the thermal conductivity, such as beads and porous carbon particles, can be added to the resin.

  As a means of controlling the heat insulation, there is a method of changing the thickness of the heat insulation layer, but it is inevitable that the heat insulation can be increased as the thickness of the heat insulation layer is increased. In the case of controlling by this, it is desirable that the bottom of the pan is relatively thin and the film is made thicker toward the top of the pan.

  The heat insulation layer at the bottom of the pan is generally 20-100 μm, and the film thickness on the side of the pan is 1.5 times greater than the average film thickness on the bottom of the pan, and the lower part of the side connecting the bottom and the side is It is desirable that the film thickness be intermediate between the two.

  In particular, it is important to set the bottom temperature sensor abutting portion of the bottom portion of the pan to be thin because the temperature cannot be sufficiently detected by the sensor.

  On the other hand, it is also possible to control the heat insulation by changing the amount of fillers that reduce the thermal conductivity, such as hollow glass beads, hollow ceramic beads, porous carbon particles, etc. added to the heat insulation layer. In particular, by increasing the amount of the filler added and increasing the hollow portion in the heat insulating layer, it is possible to reduce the thermal conductivity and improve the heat insulating property.

  In this case, the heat conductivity of the heat insulation layer on the bottom of the pan is relatively high, and it is desirable to change the amount of additive, the particle diameter, and the material so that the heat conductivity becomes higher on the side of the pan. The heat insulation can be increased from the bottom of the pan toward the side of the pan.

  In the case of hollow glass beads, it is desirable to provide a layer containing 10 to 30% by weight in the coating film with an average particle diameter of 10 to 80 μm and a specific gravity of 0.05 to 0.5 g / ml on the magnetic metal surface. .

  If the hollow glass beads are less than 10% by weight, the performance of sufficiently confining heat in the pan is not exhibited, and if it exceeds 30% by weight, the coating film is brittle and does not have a function as a film, so 10% to 30% by weight. Is desirable.

  Furthermore, it is possible to suppress heat dissipation from the pan by providing a heat reflecting layer on the surface of the heat insulating layer and suppressing heat radiation. By providing a heat reflecting layer having a low emissivity, that is, a heat reflectance higher than that of the heat insulating layer, heat dissipation can be further reduced, and the heat insulating effect of the heat insulating layer can be further improved.

  The inner surface of the pan is usually treated with a fluorine resin coat for improving non-adhesiveness.

  As described above, a heat insulating layer with low thermal conductivity is provided on the surface of the magnetic metal layer, the heat insulating layer sequentially increases its heat insulating property from the bottom of the pan to the side of the pan, and further, the surface of the heat insulating layer has a heat reflecting layer. By providing, it is difficult for the heat generated in the magnetic metal layer to escape to the outside, and the cooking result can be positively affected.

  According to this configuration, heat insulation is improved as it goes from the bottom of the pan to the side of the pan, and especially on the side of the pan, this configuration reduces thermal conductivity and is stored in the upper part of the pan during cooking. When the heat is contained, the heat is evenly transmitted to the rice, and the taste can be improved.

  On the contrary, the heat insulation performance decreases as it becomes the lower part of the side or the bottom of the pan, but these parts are the part where the magnetic metal layer of the pan generates heat and the surrounding part facing the electromagnetic induction heating coil arranged inside the main body. The surface of this part is given a very high heat insulation, and if heat accumulates in the bottom of the pan, it will cause the rice to be denatured due to excess heat, resulting in a strong adverse effect on the taste. To lower.

  In addition, the side part lower part described here shows the site | part of the height to about 1/3 of the total height from a pan lower end, and a side part shows the upper part from it.

The first invention is a heat reflective layer to be processed on the surface of those heat insulating layers is a cooker having a pot far-infrared emissivity is characterized by a decreased toward the pan bottom in a pan side is there.

  In the present invention, on the bottom surface, the heat insulating property of the heat insulating layer is lower than that of the side surface, and the infrared radiation emissivity of the heat reflecting layer is high, so that heat is relatively easy to escape, In the side surface portion, the heat insulating property of the heat insulating layer is higher than that of the bottom surface, and the infrared radiation emissivity of the heat reflecting layer is low, so that the heat hardly escapes.

  With this configuration, heat hardly stays at the bottom of the pot, and heat tends to accumulate toward the top of the pot, so that the taste can be improved.

Furthermore, the first invention, the cross-sectional heat layer has a thermally reflective layer in the outermost layer, with the said heat reflecting layer containing metallic flakes, sequentially toward the pan side the concentration of the metal flakes from the pot bottom It is a rice cooker comprising a pan characterized by being raised.

  Examples of the metal flakes added to the heat reflecting layer include aluminum, stainless steel, nickel, copper, gold, silver, and various alloys. These metals have a high effect of reflecting heat, and the higher the additive concentration, the higher the concentration. The effect of reducing the far-infrared emissivity of the heat reflecting layer and preventing heat dissipation from the pan is enhanced.

  For example, when aluminum flakes are added to the heat-resistant resin constituting the heat reflecting layer, the thickness of the heat reflecting layer is set to 20 μm at the bottom of the pan, and is added within a range of 10% by weight, and 10 wt. It is desirable to increase the amount of aluminum flakes added to the top of the pan in the range of 5% to 5% by weight.

  However, adding aluminum flakes in an amount of 5.0% by weight or more is not preferable because it adversely affects corrosion resistance and electromagnetic induction heating characteristics.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings by taking an electromagnetic induction heating rice cooker as an example. Note that the present invention is not limited to the embodiments.

  1 is a cross-sectional view of a rice cooker equipped with a pan for an electromagnetic induction heating rice cooker according to Embodiment 1 of the present invention, FIG. 2 is a schematic view of the same rice cooker pan, and FIG. 3 is a detailed schematic view of a cross-section of the pan. .

  As shown in FIG. 1 and FIG. 2, the rice cooker body 1 detachably accommodates a pan 9, and is provided with an electromagnetic induction heating coil 3 facing the bottom 15 and the lower side surface 13 of the pan 9, It is configured to heat by induction heating. A ferrite 4 for preventing magnetism is provided outside the electromagnetic induction heating coil 3. The lid 2 covers the upper opening of the pan 9 so as to be freely opened and closed, and an inner lid 7 is detachably installed on the inner surface of the lid 2.

  The pan bottom temperature detection sensor 8 is provided facing the bottom center portion 16 of the pan and detects the temperature of the pan 9, and its output is input to the heating control board 5. The heating control board 5 has a microcomputer, an inverter circuit that supplies a high-frequency current to the electromagnetic induction heating coil 3, operates while being cooled by the board cooling fan 10, and based on an input from the operation unit 6, It is comprised so that rice cooking and a heat retention process may be performed by the program control by a microcomputer. Reference numeral 11 denotes a steam cap.

  Here, as shown in FIG. 3, the pan 9 is made of a clad material in which a ferrite stainless steel having a thickness of 0.5 mm is used as a magnetic metal layer 17 and an aluminum 18 having a thickness of 1.0 mm is joined thereto. The magnetic metal layer 17 side is the outer surface and is pressed into a pan shape.

  A surface of the aluminum 18 on the inner surface of the pan 9 is treated with a two-layer fluororesin coat 19.

  After the base material is press-molded into a pan shape and washed, sand blasting is applied to the surface of the aluminum 18 on the inner surface of the pan, and the surface roughness Ra is adjusted to 2 to 5 μm. Thereafter, the fluororesin, the adhesive component, the pigment, A liquid primer coating containing a glittering material as a coating film component was applied to a film thickness of about 10 μm after film formation, and dried at 100 ° C. for 20 minutes.

  When drying of the primer is completed and the substrate temperature is sufficiently lowered, the water level line indicator is printed on the primer on the side of the pan by using a color ink different from the color of the primer by pad printing. As a coating treatment, a fluororesin powder coating material containing no additives such as pigments and glittering materials was applied on the primer and the water level line display portion so as to have a film thickness of 35 μm after film formation. At this time, the fluororesin used was PFA powder, and this powder coating was applied, followed by baking at 380 ° C. for 20 minutes to form a film on the fluororesin coat.

  On the other hand, on the outer surface of the magnetic metal layer 17 constituting the outer layer of the pan base material, the roughened surface 20 is formed by adjusting the surface roughness Ra to 0.5 to 3 μm by sandblasting, A polyethersulfone resin coating containing hollow glass beads having an average particle size of 30 μm as the filler 21 was applied to the surface of the magnetic metal layer 17 to form a heat insulating layer 22.

  This polyethersulfone resin paint is applied after baking to have an average film thickness of 40 to 100 μm at the bottom 15 of the pan, 100 to 200 μm at the lower side 13, and 200 to 400 μm at the upper side 14. The amount of hollow glass beads contained in the membrane was 10% by weight, and the thermal conductivity of this coating film was 0.18 W / m · k.

  The amount of hollow glass beads can be added up to about 30% by weight in the coating film. However, when the concentration becomes high, the amount of resin in the coating film becomes relatively small, and the coating film becomes uncoordinated and brittle. Therefore, it is possible to add about several percent by weight of glass fiber, potassium titanate fiber, talc or the like in the paint to improve the unity of the resin.

  Since the polyethersulfone resin layer containing hollow glass beads as a filler has low thermal conductivity, temperature detection is sufficient when the resin layer is applied at the portion 16 where the temperature sensor provided in the rice cooker body contacts. Since it could not be performed, a thin coating was applied to a film thickness of about 40 μm.

  Next, a resin paint mainly composed of polyethersulfone is applied to the upper layer of the heat insulating layer as the heat reflection layer 23. The paint is mainly composed of a resin component and a pigment, and mica having an average particle diameter of 40 μm is added as an additive. In this embodiment, the entire outer surface of the pan was coated with a thickness of 20 μm.

  The heat reflecting layer 23 contains 5 to 25% by weight of mica, but in order to improve heat reflectivity, it is desirable to use a material having high glitter such as gold, silver, copper, etc. It is important to set the amount of mica added and the film thickness so as to sufficiently conceal the layer.

  These coatings may be continuous coating at appropriate intervals, or may be provided with a drying time of about 100 ° C. for about 10 minutes after each coating, but finally at 280 to 300 ° C. for 15 to 30 minutes. Firing was performed to form an outer coating.

  Needless to say, these coating conditions can be changed depending on what kind of resin is used, and two or more heat insulating layers may be used. In order to improve the adhesion between the heat insulating layer and the base material, a primer is provided on the base material. It may be painted.

(Embodiment 2)
Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings by taking an electromagnetic induction heating rice cooker as an example. In Embodiment 2, the electromagnetic induction heating type described in Embodiment 1 will be described. The same rice cooker is used. Note that the present invention is not limited to the embodiments.

  Here, as shown in FIG. 3, the pan 9 has a thickness of 0.5 mm of ferritic stainless steel as the magnetic metal layer 17 as shown in FIG. The clad material to which 18 is bonded is used as a base material, and is made into a pan shape by pressing the magnetic metal layer 17 side as an outer surface.

  Further, as in the first embodiment, the surface of the aluminum 18 on the inner surface of the pan 9 is treated with a two-layer fluororesin coat 19.

  On the other hand, on the outer surface of the magnetic metal layer 17 constituting the outer layer of the pan base material, the roughened surface 20 is formed by adjusting the surface roughness Ra to 0.5 to 3 μm by sandblasting, A primer layer made of an adhesive component was applied to a thickness of about 1 μm after film formation, and a polyethersulfone resin coating containing hollow glass beads having an average particle size of 30 μm as a filler 21 was applied to the surface of the magnetic metal layer 17. The heat insulating layer 22 was painted.

  This polyethersulfone resin paint is applied after baking to have an average film thickness of 40 to 100 μm at the bottom 15 of the pan, 100 to 200 μm at the lower side 13, and 200 to 400 μm at the upper side 14. The amount of hollow glass beads contained in the membrane was 10% by weight, and the thermal conductivity of this coating film was 0.18 W / m · k.

  Since the polyethersulfone resin layer containing hollow glass beads as a filler has low thermal conductivity, temperature detection is sufficient when the resin layer is applied at the portion 16 where the temperature sensor provided in the rice cooker body contacts. Since it could not be performed, a thin coating was applied to a film thickness of about 40 μm.

  Next, a resin paint mainly composed of polyethersulfone is applied to the upper layer of the heat insulating layer as a heat reflecting layer. This paint is mainly composed of a resin component and a pigment, and mica and aluminum flakes having an average particle diameter of 40 μm. It is contained as an additive 24, and in the present embodiment, the entire outer surface of the pan is coated with a thickness of 20 μm.

  The heat reflective layer contains an appropriate amount of mica, but in order to increase heat reflectivity, it is desirable to use a highly glittering material such as gold, silver, copper, etc., and sufficiently hide the underlying heat insulation layer Thus, it is important to set the amount of mica added and the film thickness.

  In the second embodiment, the pot part is divided into three parts on the bottom, under the side, and on the side, and the amount of mica and aluminum flakes to be included in the heat-reflective coating is changed as shown in FIG. divided.

  As shown in FIG. 4, it is possible to change the far-infrared emissivity by changing the addition amount of mica and aluminum flakes, and the far-infrared emissivity of the heat reflecting layer is low at the side surface, that is, the heat The heat insulation layer is thick because it has many reflections and is excellent in heat insulation, while the bottom part has a high far-infrared emissivity of the heat reflection layer and the heat insulation layer is thin so that it has low heat insulation and heat. Can be radiated relatively quickly, so that excess heat is not stored. Moreover, in the lower part of the side surface, the heat insulation is intermediate between the bottom and the side surface.

  As described above, the pot of the electromagnetic induction heating rice cooker according to the present invention is provided with the heat insulating layer and the heat reflecting layer on the surface of the magnetic metal layer constituting the outer layer of the pan base material, so the heat insulating property is controlled for each part. Since cooking performance can be improved by doing, it is useful also as a pan of other electromagnetic induction heating type cooking utensils.

9 Pot 21 Filler 22 Heat insulation layer 23 Heat reflection layer 24 Additive

Claims (1)

A heat insulating layer provided on the outer surface of the substrate and a heat reflecting layer provided on a surface layer of the heat insulating layer, the heat conductivity of the heat insulating layer being 0.3 W / m / k or less, and the bottom surface thereof From the bottom of the pan to the side of the pan, the thickness of the heat-insulating layer increases, and the pan The heat reflective layer contains metal flakes, and the pan has a higher content of the metal flakes in the heat reflective layer as it goes from the bottom of the pan to the side of the pan. The rice cooker in which the far-infrared emissivity of the heat reflection layer decreases from the bottom to the side of the pan .

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