JP2012223223A - Cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce uneven heating inside a pot caused by local heating of a heat generating area.SOLUTION: The cooker includes the pot 2 which has an opening on the upper surface and a plurality of irregular areas X, Y and Z formed from a side surface to a bottom surface, and a pot heating means 4 disposed on the outer side where the irregular areas X, Y and Z of the pot 2 are not formed. The irregular areas are formed in such a shape that the irregularity on the inner side corresponds to the irregularity on the outer side in such a way that a recess on the inner side is a projection on the opposite outer side. Accordingly, the quantities of heating per unit area to be applied to an object to be cooked from the area where the irregularity is formed and from the area where the irregularity is not formed are approximate to each other. As the pot is uniformly heated, boiling occurs uniformly from the whole area near the bottom of the pot, and the whole object to be cooked is uniformly heated by the uniform heat transfer of the boiling. As a result, cooking of the object to be cooked (specifically, gelatinization if the object to be cooked is rice) is facilitated in any part of the pot, and the object to be cooked on the whole pot can be deliciously cooked in the cooker.

Description

  The present invention relates to a cooking device for reducing cooking unevenness caused by a pan heating means at the bottom, particularly an induction heating type pan heating means, and improving cooking performance.

  Conventionally, pans used in this type of cooker for electromagnetic induction heating such as rice cookers that are widely marketed to the general public, the base material is formed from a single aluminum, or a laminate of aluminum and stainless steel and aluminum The mainstream is a composite material such as a laminate of stainless steel and copper.

  In these metal rice cooker pans, a fluororesin coat is treated on the inner surface in order to prevent the rice that is normally cooked from sticking strongly, thereby improving the non-adhesiveness to the rice.

  In some of these pans, the bottom surface of the pan is provided with irregularities to increase the contact area and improve the bonding (see, for example, Patent Document 1). This also has an advantage in that the heating efficiency of electromagnetic induction heating can be improved by increasing the area of the heat generating member to increase the heat generating area, and the strength can be improved by work hardening.

  In particular, the electromagnetic induction heating rice cooker that can improve the heating efficiency by properly applying the technology to provide an uneven portion in the pan to the electromagnetic induction heating rice cooker, and can also cook rice with less cooking unevenness while suppressing uneven heating. Some are intended to provide.

  FIG. 7: is the principal part expanded sectional view of the bottom face of the pan of each different aspect of the conventional rice cooker described in patent document 1, and the one part expanded sectional view, (a)-(d) is respectively different. An example is shown. As shown in FIG. 7 which is a partial cross-sectional view of the pan, a plurality of concave and convex portions are formed on both the inner surface side and the outer surface side of the pan or only on the outer surface side.

  During cooking, when the heating layer of the pan is heated by energization of the induction heating coil, the pan is efficiently heated by the surface area of the heating layer being increased by the concavo-convex portion. In addition, since there are uneven portions, the heat generation direction is not only one direction with respect to the inner surface of the pan, so heat is quickly transferred to the pan body away from the heat generating portion, and uneven heating of the entire pan body is suppressed. The

  Thereby, the heating density of the inner surface of a pan reduces and it is suppressed that the rice of the part which contacted the pan by excessive heating becomes too soft. In addition, since the bottom surface of the pan and the curved portion at the bottom of the side surface have uneven portions, heating of only the bottom surface does not become excessively strong, and heating of the bottom of the side surface is not weakened, and uneven heating is suppressed. Is done.

JP-A-9-140566

  However, in the conventional configuration, it is difficult to completely prevent the heating unevenness of the pan, and the heat generation part facing the induction heating coil is locally heated.

  That is, the heat generation area becomes large due to the uneven part and a rapid temperature rise does not occur, but if the pot composite material is equivalent, there is no significant difference between the heat conduction other than the heat generation part with and without the uneven part Conceivable.

  Therefore, it is thought that boiling mainly arises from the heat-generating part facing the induction heating coil, and there is a problem that the heating unevenness in the pan cannot be reduced.

  An object of the present invention is to solve the above-described conventional problems, and in particular, to provide a cooking device with improved cooking performance by reducing uneven heating by induction heating type pan heating means.

  In order to solve the conventional problem, the cooking device of the present invention has an opening on the top surface, and forms a plurality of uneven portions from the side surface to the bottom surface, and the uneven portion has a concave shape on the inner surface side. Are arranged such that the concave and convex shapes on the inner surface side and the outer surface side correspond to each other so that the opposite outer surface side has a convex shape, and the pan heating means is disposed on the outer surface side where the concave and convex portions of the pan are not formed. It is a thing.

  As a result, the coupling between the pot heating means and the portion not provided with the uneven portion during cooking does not change, and the connection with the portion provided with the uneven portion away from the pot heating means is improved. Since the heat generation itself becomes uniform, uniform heating of the pan can be realized.

  In particular, when the pan heating means is an induction heating coil and the pan is formed of a base material made of a magnetic metal, the induction heating coil's electromagnetic field does not change the coupling with the portion where the uneven portion is not provided, and induction heating is performed. Coupling with the part where the uneven part apart from the coil is provided is improved and the heat generation of the pan itself becomes uniform, so the pan is uniform without depending on the heat conduction by the material of the pan Heating can be realized.

  If the input power to the induction heating coil is the same, the amount of heat generation per unit area in the portion where the uneven portion is provided away from the induction heating coil increases, and on the contrary, the portion where the uneven portion is not provided The calorific value per unit area at is reduced. Therefore, the amount of heating per unit area from the portion where the uneven portion that is far from the induction heating coil is provided to the object to be cooked increases, and the unit area from the portion where the uneven portion is not provided to the object to be cooked By reducing the amount of heating per hit, the amount of heating per unit area of the object to be cooked as a whole pan approximates.

  Therefore, when the pan is heated uniformly, boiling occurs uniformly from the whole bottom of the pan, and the entire cooked food is heated uniformly by the uniform boiling heat transfer. Can be provided, and a cooking device can be provided that cooks the cooked food of the entire pan in a delicious manner.

  Especially when the cooked food is rice, it is the ideal way to cook rice, and the cooker can be reproduced with an electromagnetic induction heating rice cooker. Causes boiling evenly from the entire bottom of the pan, and the uniform boiling heat transfer uniformly heats the whole rice, promoting the gelatinization of the rice in any part of the pan without any variation, and heating the rice in the pan deliciously. A cooker can be provided.

The heating cooker of the present invention approximates the amount of heating per unit area from the portion where the uneven portion is provided and the portion where the uneven portion is not provided to the object to be cooked, and the pan is uniformly heated so that the entire pan bottom Boiled evenly, and the entire cooked food is heated uniformly by the uniform boiling heat transfer, and the cooked food in any part of the pan is cooked evenly (especially when the cooked food is rice) It is promoted and can cook the cooked food of the whole pan deliciously.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. (A) of the pan in Embodiment 1 of the present invention is a plan view (b) is a front view The principal part expanded sectional view of the pan bottom in Embodiment 1 of this invention The principal part expanded sectional view of the pan bottom of another mode in Embodiment 1 of the present invention. The principal part expanded sectional view of the pan bottom of another mode in Embodiment 1 of the present invention. The expanded perspective view of the fluororesin coat | court of the pan bottom in Embodiment 1 of this invention (A)-(d) of the conventional rice cooker is a principal part expanded sectional view of the bottom of a pan of another mode, respectively (e) is a sectional view of a part of pan

  1st invention has an opening part in an upper surface, forms a some uneven | corrugated | grooved part from a side surface to a bottom face, and when the inner surface side is concave shape, the outer surface side which opposes becomes convex shape A pan having a shape corresponding to the concave and convex shapes on the inner surface side and the outer surface side, and a pan heating means on the outer surface side where the concave and convex portion of the pan is not formed, so that the pan heating means and the concave and convex portion during cooking. Because the coupling with the part where the unevenness part apart from the pot heating means is improved, the coupling with the part where the pot is not provided is improved, and the heat generation of the pot itself is made uniform , Uniform heating of the pan can be realized.

  In particular, when the pan heating means is an induction heating coil and the pan is formed of a base material made of a magnetic metal, the induction heating coil's electromagnetic field does not change the coupling with the portion where the uneven portion is not provided, and induction heating is performed. Coupling with the part where the uneven part apart from the coil is provided is improved and the heat generation of the pan itself becomes uniform, so the pan is uniform without depending on the heat conduction by the material of the pan Heating can be realized.

  If the input power to the induction heating coil is the same, the amount of heat generation per unit area in the portion where the uneven portion is provided away from the induction heating coil increases, and on the contrary, the portion where the uneven portion is not provided The calorific value per unit area at is reduced. Therefore, the amount of heating per unit area from the portion where the uneven portion that is far from the induction heating coil is provided to the object to be cooked increases, and the unit area from the portion where the uneven portion is not provided to the object to be cooked By reducing the amount of heating per hit, the amount of heating per unit area of the object to be cooked as a whole pan approximates.

  Therefore, when the pan is heated uniformly, boiling occurs uniformly from the whole bottom of the pan, and the entire cooked food is heated uniformly by the uniform boiling heat transfer. Can be provided, and a cooking device can be provided that cooks the cooked food of the entire pan in a delicious manner.

  Especially when the cooked food is rice, it is the ideal way to cook rice, and the cooker can be reproduced with an electromagnetic induction heating rice cooker. Causes boiling evenly from the entire bottom of the pan, and the uniform boiling heat transfer uniformly heats the whole rice, promoting the gelatinization of the rice in any part of the pan without any variation, and heating the rice in the pan deliciously. A cooker can be provided.

  In the second invention, in particular, the plurality of uneven portions of the first invention are formed at the same time when the pan is molded, so that it is not necessary to form unevenness in the base material in advance. As productivity improves, the unevenness | corrugation of the target shape can be formed more reliably and the boiling from a recessed part is accelerated | stimulated, and heat can be uniformly transmitted to a to-be-cooked object by boiling heat transfer.

  That is, even if the portion provided with the uneven portion that is separated from the pan heating means has a lower calorific value than the portion not provided with the uneven portion, the concave portion improves the bubbling of the boiling bubbles. Because it has an effect, it promotes nucleate boiling rather than film boiling.

  Therefore, the whole cooking object is uniformly heated by the uniform boiling heat transfer of the whole pan, and the gelatinization of all the cooking parts in the pan is promoted without any variation, and the cooking of the whole pan is cooked deliciously. Can be provided.

  In a third aspect of the invention, in particular, the pan of the first or second aspect of the invention is formed of a base material made of a magnetic metal, and the plurality of concavo-convex portions are arbitrary from the middle of the side surface of the pan to the bottom surface. Starting from the outer periphery of the base plate, the base is formed on the base material over the bottom surface, and the pot heating means is an induction heating coil, so that the electromagnetic field of the induction heating coil during cooking is a portion where the uneven portion is not provided. The coupling of the pot does not change, and the coupling with the part with the uneven part that is far from the induction heating coil is improved, and the heat generation of the pot itself becomes uniform, so the heat conduction by the pot material The pan can be heated evenly without depending on it.

  If the input power to the induction heating coil is the same, the amount of heat generation per unit area in the portion where the uneven portion is provided away from the induction heating coil increases, and on the contrary, the portion where the uneven portion is not provided The calorific value per unit area at is reduced. Therefore, the amount of heating per unit area from the portion where the uneven portion that is far from the induction heating coil is provided to the object to be cooked increases, and the unit area from the portion where the uneven portion is not provided to the object to be cooked By reducing the amount of heating per hit, the amount of heating per unit area of the object to be cooked as a whole pan approximates.

  Therefore, when the pan is heated uniformly, boiling occurs uniformly from the whole bottom of the pan, and the entire cooked food is heated uniformly by the uniform boiling heat transfer. Can be provided, and a cooking device can be provided that cooks the cooked food of the entire pan in a delicious manner.

  Especially when the cooked food is rice, it is the ideal way to cook rice, and the cooker can be reproduced with an electromagnetic induction heating rice cooker. Causes boiling evenly from the entire bottom of the pan, and the uniform boiling heat transfer uniformly heats the whole rice, promoting the gelatinization of the rice in any part of the pan without any variation, and heating the rice in the pan deliciously. A cooker can be provided.

  In the fourth invention, in particular, a fluororesin coat is formed on the inner surface of the substrate of the third invention, and at least silicon carbide is added as additive particles to the fluororesin coat at the bottom of the recess of the substrate. By unevenly distributing one of the diamonds, the boiling from the recess is promoted, so that heat can be uniformly transferred to the rice by boiling heat transfer.

  That is, since fluorocarbon resin is a material with low thermal conductivity, silicon carbide and diamond have extremely high thermal conductivity, silicon carbide and diamond particles are used when silicon carbide and diamond particles are used as additive particles. Because heat from the pan is easy to be transmitted to, it becomes easy to induce the generation of bubbles from the concave portion where silicon carbide and diamond are unevenly distributed, and boiling bubbles are generated uniformly and stably from the surface of the fluororesin coat in the pan, It becomes possible to uniformly cook the food to be cooked by uniform boiling heat transfer, and to cook a delicious food with improved taste.

In the fifth invention, in particular, a fluororesin coat is formed on the inner surface of the substrate of the fourth invention, and at least silicon carbide is added as additive particles to the fluororesin coat at the bottom of the recess of the substrate. Because the powder coating with microencapsulation of either diamond is unevenly distributed, the additive particles are encapsulated in the fluororesin powder by microencapsulation. At times, they are not separated, and it is possible to obtain a homogeneous coating that always contains a certain concentration of additive particles in the micropores, and because the additive particles are also covered with fluororesin in the coating. It is possible to prevent the additive particles from falling off during use.

  In the sixth invention, in particular, a fluororesin coat is formed on the inner surface of the base material of the fourth or fifth invention, and a plurality of polygonal pyramid-shaped micropores are formed in the surface layer of the fluororesin coat other than the uneven portion. The additive particles are unevenly distributed on the surface of the fluororesin coat and are present in the lowest part of the micropores, so that the additive particles are unevenly distributed while having high wear resistance. Inducing the generation of bubbles from the pores, boiling bubbles are generated uniformly and uniformly from the surface of the fluororesin coat other than the uneven portions, and boiling bubbles are generated from the recesses, so the rice is heated uniformly by uniform boiling heat transfer It is possible to provide a heating cooker that cooks the cooked food of the entire pan in a delicious manner.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a rice cooker in the first embodiment of the present invention, FIG. 2 is a plan view of the pan in the first embodiment of the present invention, (b) is a front view, FIG. 3: shows the principal part expanded sectional view of the pan bottom in the 1st Embodiment of this invention.

  In FIG. 1, a main body 1 of a rice cooker includes a detachable pan 2. The main body 1 is provided with a lid 3 covering its upper surface so as to be freely opened and closed.

  The main body 1 includes pot heating means 4a and 4b (which are induction heating coils) for induction heating the pot 2, pot temperature detection means 5 for detecting the temperature of the pot 2, steam generating means 6 for generating steam, and control means 7. Have.

  The lid 3 includes a lid cover 8, a steam path 9 for supplying steam generated by the steam generating means 6 to the inside of the pan 2, a heating plate 10, a heating plate heating means 11, a heating plate temperature detecting means 12, and a steam cylinder 13. And a steam superheater 14.

  The heating plate 10 is detachably attached to the lid cover 8 constituting the lower surface of the lid 3. In a state where the lid 3 is closed, the gap between the pan 2 and the heating plate 10 is sealed with a loop packing (first packing) 15 attached to the heating plate 10. The heating plate heating means 11 is an induction heating coil that is attached to the lid cover 8 and induction-heats the heating plate 10. The heating plate temperature detection means 12 detects the temperature of the heating plate 10. The steam cylinder 13 discharges unnecessary steam in the pan 2.

  The steam generating means 6 has a water tank 16 and a water tank heating means 17. The water tank heating means 17 is an induction heating coil for induction heating the water tank 16. A water tank temperature detecting means 18 for detecting the temperature of the water tank 16 is pressed against the outside of the water tank 16.

  In a state where the lid 3 is closed, a steam path 9 for supplying the generated steam to the pan 2 is located above the water tank 16. A gap between the steam path 9 and the water tank 16 is sealed with a loop packing (second packing) 19 attached to the steam path 9. The steam superheater 14 is internally combined with a bent portion and a straight portion so as to avoid the internal parts of the lid 3 while considering safety.

In the state where the lid 3 is closed, the water tank 16 and the pan 2 communicate with each other only through the steam path 9.
Steam generated in the water tank 16 is introduced into the pan 2 through the steam path 9, and excess steam is discharged to the outside through the steam cylinder 13. A heating means (for example, an induction heating coil) for heating the steam path 9 may be further provided.

  The control means 7 has a microcomputer mounted on a circuit board (not shown).

  The control means 7 (microcomputer) is operated by software through an operation command input by a user via an operation panel (not shown), pan temperature detection means 5, water tank temperature detection means 18, heating plate temperature detection means 12, and steam overheat. Based on a signal input from an apparatus temperature detecting means (not shown), heating control of the pan 2, the heating plate 10, the water tank 16, and the steam superheater 14 is performed by a rice cooking program stored in advance in a microcomputer.

  The control means 7 controls the heating amount of the pot heating means 4a, 4b, the water tank heating means 17, the heating plate heating means 11, and the steam superheating means (not shown) according to the energization rate and / or energization amount of each heating means. .

  As shown in FIG. 3, the pan 2 is made of a clad material obtained by joining 1.0 mm thick aluminum 21 to 0.5 mm thick ferritic stainless steel 20, and the ferritic stainless steel 20 side is the outer surface. It is pressed and molded so that A two-layer fluororesin coat 22 is formed on the surface of the aluminum 21 on the inner surface of the pan 2.

  As shown in FIG. 2, the pan 2 takes the maximum value while the curvature increases as it goes downward from the curvature starting point at a height of approximately the middle position to approximately 1/3 of the pan height, and the lowest point. It has a shape that the curvature becomes smaller toward.

  The lowest point is a point on the outermost periphery that contacts the table surface when the pan 2 is placed on a flat surface such as a table surface. In the present embodiment, the diameter of the pan 2 including the flange portion is 220 mm, the outer diameter not including the flange portion is 195 mm, the pan height is 118 mm, the curvature start point height is 55 mm, and the bottom outer periphery includes the lowest point. The diameter was 120 mm.

  A plurality of concavo-convex portions X, concavo-convex portions Y, and concavo-convex portions Z are formed on the bottom surface portion and the curved surface portion, and the concavo-convex portions are outside the base material of the opposite pan 2 when the base material inside of the pan 2 is concave. Has a convex shape. The uneven portion is formed at the same time as the press working.

  In a state where the pan 2 is mounted on the main body 1, an induction heating coil is provided in a portion where the concave and convex portions of the bottom surface portion and the curved surface portion are not provided. That is, the pot heating means 4a and 4b are arranged in a portion where the uneven portion between the uneven portion X, the uneven portion Y, and the uneven portion Z is not provided.

  The operation | movement in the rice cooking process of the rice cooker of embodiment of this invention comprised as mentioned above is demonstrated.

  A user puts rice to be cooked and water corresponding to the amount of the rice into the pan 2 and decorates the main body 1. A predetermined amount of water is placed in the water tank 16 and is internally provided in the main body 1. When the user operates a rice cooking start switch (not shown), the rice cooking process is performed.

  The rice cooking process is largely divided into pre-cooking, cooking, boiling maintenance, and steaming in order of time.

  In the pre-cooking process, until the first predetermined time t1 (usually around 20 minutes), the pan 2 is heated so that the temperature of the pan 2 becomes the first predetermined temperature T1 (usually around 55 ° C.) suitable for water absorption of rice. The means 4a and 4b are controlled, the pot 2 is heated, and the rice and water in the pot 2 are heated.

  The pre-cooking step is a step for sufficiently gelatinizing the center of the rice in the subsequent steps by immersing the rice in water having a temperature lower than the gelatinization temperature and allowing the rice to absorb water in advance. In addition, this step is also a step of decomposing starch by amylase contained in rice to produce glucose, and here, the sweetness of rice is produced.

  Next, after the pre-cooking process, the process proceeds to the cooking process. In the cooking process, the pan 2 is heated with a predetermined amount of heat by the pan heating means 4a and 4b until the temperature of the pan 2 reaches a second predetermined temperature T2 (boiling point of water (usually around 100 ° C.)). The amount of cooked rice is determined based on the temperature rise rate of the pan 2 at this time.

  In this step, the pan heating means 4 is controlled by the detected temperature of the pan temperature detecting means 5, but a lid temperature detecting means for detecting the temperature of the lid covering the opening of the pot is provided separately, and the detected temperature of the lid temperature detecting means. The pan heating means 4 can heat the pan 2 until the temperature reaches a predetermined temperature.

  Then, after the cooking process ends, the process proceeds to the boiling maintenance process. In the boiling maintaining step, while the pot 2 has water, the detected temperature Ta of the pot temperature detecting means 5 maintains the boiling state at the second predetermined temperature T2 (boiling point of water (usually around 100 ° C.)). The pot heating means 4a, 4b and the heating plate heating means 11 are controlled to heat the rice and water in the pot 2. And if the boiling maintenance process passes, the water in the pan 2 will evaporate, and if there is no water in the pan 2, the temperature of the pan 2 will rise.

  When the detected temperature Ta of the pot temperature detecting means 5 reaches the third predetermined temperature T3 (above the boiling point of water), it is determined that there is no water in the pot 2 and the process ends. This step is a step of gelatinizing rice starch, and the degree of gelatinization of rice after cooking reaches nearly 100%, but the degree of gelatinization is about 50 to 60% at the end of this step.

  Finally, go to the steaming process. In the steaming step, the heating (cooking) by the pan heating means 4 and the heating plate heating means 11 according to the amount of cooked rice and the heating stop (pause) are repeated a plurality of times during a predetermined time. In the steaming step (at the time of additional cooking and at rest), the steam generated from the steam generating means 6 is superheated by the steam superheater 14 and superheated steam is supplied into the pan 2.

  The steaming process is a process of gelatinizing rice starch following the boiling maintaining process, and the gelatinization degree was about 50 to 60% at the start of the steaming process, but at the end of the steaming process, that is, at the end of rice cooking, The degree of gelatinization reaches nearly 100%.

  In the boiling maintaining process from the cooking process, the temperature of the water in the pot 2 rapidly rises from 50 ° C. to 100 ° C. by continuous energization to the pot heating means 4a, 4b. At this time, the water in the pan gradually changed from the initial (1) unboiled natural convection to the (2) nucleate boiling state where the bubbles generated on the surface of the fluororesin coat 22 did not reach the water surface. ) Nucleate boiling occurs in which bubbles generated on the surface of the fluororesin coat 22 reach the water surface.

  Next, natural convection and nucleate boiling will be described using the above (1) to (3) as specific examples. The surface heat flux q = Q / A of the pan 2 is obtained by dividing the Joule heating amount Q by the pan heating means 4a and 4b by the heat generating surface area A of the pan 2, and the pressure in the pan 2 from the surface temperature T of the pan 2 The value obtained by subtracting the saturation temperature Tsat is defined as the degree of superheat ΔTsat = T−Tsat.

(1) While the pan 2 is heated by the pan heating means 4a and 4b and the degree of superheat ΔTsat is small, the surface of the fluororesin coat 22 generates heat due to heat transfer, and the water in the pan 2 that is in contact with the surface of the fluororesin coat 22 Is locally heated, resulting in a density difference in the water. A local buoyancy based on this density difference is generated, and a flow is induced in the water in the pan 2. Such local non-uniform density causes unboiled natural convection in the water in the pot 2. The heat transfer from water to rice at this time is natural convection heat transfer.

  (2) As the degree of superheat ΔTsat increases, nucleate boiling occurs in which small bubbles are generated on the surface of the fluororesin coat 22 and then detached. In the initial nucleate boiling, the amount of heat contained in the bubbles is not sufficient, so as the temperature rises toward the water surface, the temperature of the bubbles approaches the water temperature, liquefies as a result of recondensation, and the bubbles disappear (the bubbles are on the water surface). Nucleate boiling not reached). The heat transfer from water to rice at this time is natural convection heat transfer and boiling heat transfer.

  (3) Further, as the Joule heating value Q increases, the generation point of bubbles becomes dense and frequently leaves, and bubbles reach the water surface, and the entire water in the pot 2 is vigorously stirred. (Nuclear boiling). The heat transfer from water to rice at this time is boiling heat transfer.

  Next, the phenomenon actually occurring in the pan 2 will be described below.

  In the state (1), natural convection heat transfer is dominant in the heat conduction from water to rice, and a large difference in the heat flux q due to the difference in the surface state of the fluororesin coat 22 is not recognized.

  In the state of (2), heat conduction from water to rice is divided into a case where natural convection heat transfer is dominant and a case where boiling heat transfer is dominant depending on how bubbles are generated on the surface of the fluororesin coat 22. .

  That is, the former is a case where bubbles grow large on the surface of the fluororesin coat 22, and most of the Joule heating value Q is spent on the growth of bubbles, so that heat transfer from water to the rice is from the surface of the fluororesin coat 22 Heat transfer from the water in the pan 2 and heat transfer from the bubbles to the water, both of which are transferred to the rice by natural convection heat transfer.

  On the other hand, the latter is a case where bubbles are easily detached on the surface of the fluororesin coat 22, and the bubbles are fine as described above, and the bubbles rise toward the water surface by buoyancy, but the amount of heat contained in the bubbles. Therefore, as the temperature rises, the temperature of the bubbles approaches the water temperature, and as a result of recondensation, the bubbles are liquefied and the bubbles disappear.

  However, the bubbles frequently rise toward the water surface, so that forced convection occurs in the water in the pan 2, and heat is transferred to the rice by boiling heat transfer and forced convection heat transfer. In forced convection heat transfer, natural heat transfer is more uniform than in natural convection heat transfer, so uniform heat transfer to rice can be achieved. Therefore, the rice can be heated uniformly by making the surface of the fluororesin coat 22 into a surface state in which air bubbles are easily detached.

  In the state of (3), the bubbles frequently leave and reach the water surface, and the entire water in the pan 2 is vigorously stirred.

  However, depending on how bubbles are generated on the surface of the fluororesin coat 22, the rice is not always heated uniformly in boiling heat transfer. That is, when bubbles are easily detached from the surface of the fluororesin coat 22, the opportunity for heat transfer to the rice is increased by increasing the contact opportunities between the bubbles and the rice as compared with the case where the bubbles grow large. . Therefore, the rice can be heated uniformly by making the surface of the fluororesin coat 22 into a surface state in which air bubbles are easily detached.

  As described above, in nucleate boiling, the surface of the pan 2 is made to be in a state in which bubbles are easily released, so that the opportunity for contact between the bubbles and the rice increases, so that the opportunity for heat transfer to the rice increases. Can be uniformly heated.

  Next, the surface state in which bubbles are easily released will be described below.

  As for the bubble growth, how the curvature 1 / R of the bubble changes as the bubble trapped in the conical recess having the exit radius R grows will be described.

  Assuming that the contact angle of the bubble to the heating surface is 90 °, the curvature of the bubble accompanying the growth of the bubble takes a minimum value in a state where the bubble is just around the outlet and is kept 90 ° with the side of the cone, After that, it is in contact with the area around the outlet, but continues to increase until it shows a contact angle of 90 ° with the heated surface (stable equilibrium state). After reaching the maximum value, the contact position moves away from the area around the outlet again. It will decrease.

  As the volume of the bubble increases, the curvature decreases, becomes unstable and continues to grow towards bubble detachment.

  As described above, in order to easily remove bubbles from the heating surface, how to place the bubbles in an unstable state is important. To that end, it is conceivable to optimize the material of the heating surface and the shape of the recess, but for the reasons described above, it is desirable to use a fluororesin, so we decided to optimize the shape of the recess. .

  As shown in FIGS. 1 and 2, the shape of the concave portion is preferably a shape in which peaks and valleys are continuous in order for the adjacent bubbles to pressurize each other and promote the detachment of the bubbles. Shaped.

  Moreover, the uneven | corrugated | grooved part of the pan 2 is made into the convex shape in the base-material outer side which opposes, when the base material inside is concave shape, and the uneven | corrugated part between the uneven | corrugated part X, the uneven | corrugated part Y, and the uneven part Z is not provided. In addition, pot heating means 4a and 4b are arranged.

  Thereby, the electromagnetic field of the pan heating means 4a and 4b does not change the coupling with the portion where the uneven portion is not provided, and the portion where the uneven portion apart from the pot heating means 4a and 4b is provided and Since the heat generated in the pan 2 is made uniform and the heat generation itself of the pan 2 is made uniform, uniform heating of the pan 2 can be realized without depending on the heat conduction by the material of the pan 2.

  If the input power to the pot heating means 4a and 4b is equivalent, the heat generation amount per unit area in the concavo-convex part X, concavo-convex part Y and concavo-convex part Z that are separated from the pot heating means 4a and 4b increases, The amount of heat generated per unit area in the portion where the uneven portion is not provided is reduced.

  Therefore, the heating amount per unit area from the uneven portion X, the uneven portion Y, and the uneven portion Z away from the pan heating means 4a and 4b to the rice increases, and the portion from which the uneven portion is not provided to the rice By reducing the heating amount per unit area, the heating amount per unit area to the rice as a whole of the pan 2 is approximated.

  In other words, it is possible to reproduce the oven cooking rice, which is an ideal way to cook rice, with an electromagnetic induction heating rice cooker. Like the oven cooking rice, when the pan is heated uniformly, the entire boiling area of the pan is boiled uniformly, and the uniform boiling heat transfer heats the whole rice uniformly, and the rice in any part of the pan is evenly glued. The rice cooker that cooks rice in the whole pan deliciously can be provided.

  FIG. 4: shows the principal part expanded sectional view of the pan bottom of another aspect in the 1st Embodiment of this invention.

  As shown in FIG. 4, by using a rice cooker in which at least one additive particle A of silicon carbide or diamond is unevenly distributed on the fluororesin coat 22 at the bottom of the recess, boiling from the recess is promoted. Therefore, heat can be evenly transferred to the rice by boiling heat transfer.

  Fluororesin is a material with low thermal conductivity, whereas silicon carbide and diamond have extremely high thermal conductivity, so when silicon carbide or diamond particles are used as additive particles, the additive particles can be removed from the pan. Heat is easily transmitted, so that it is easy to induce the generation of bubbles from the concave portion where the additive is unevenly distributed, and the boiling bubbles are generated uniformly and stably from the surface of the fluororesin coat 22 in the pan. It becomes possible to cook delicious rice with even better taste by heating the rice uniformly with heat.

  In addition, by making the surface of the pan 2 the above specifications, the contact portion is sharp, so it has high wear resistance against wear loads such as rice sharpening, and improves durability against peeling of the fluororesin coat, etc. Can do. In addition, the number of rice sharpening operations can be reduced accordingly.

  The additive particles A are unevenly distributed in a powder coating in which at least one of silicon carbide and diamond is microencapsulated, so that the additive particles A are encapsulated in the fluororesin powder by microencapsulation. Therefore, both of them do not separate when the fluororesin powder coating is applied, and it is possible to obtain a uniform coating film containing additive particles at a constant concentration in the micropores. Is covered with a fluororesin, so that the additive particles can be prevented from falling off during actual use.

  FIG. 5 is an enlarged cross-sectional view of the main part of the pan bottom according to another aspect of the first embodiment of the present invention, and FIG. 6 is an enlarged perspective view of the fluororesin coat on the pan bottom according to the first embodiment of the present invention. Is shown.

  As shown in FIGS. 5 and 6, a plurality of polygonal pyramid-shaped micropores B are formed in the surface layer of the fluororesin coat 22 other than the uneven portions, and the additive particles C are unevenly distributed in the surface layer of the fluororesin coat 22. Most present at the bottom of the hole B.

  Thereby, while having high wear resistance, the generation of bubbles from the fine holes B in which the additive particles C are unevenly distributed is induced, and the boiling bubbles are uniformly stabilized from the surface of the fluororesin coat 22 other than the uneven portions. Since it is generated and boiling bubbles are generated from the recess, the rice can be uniformly heated by uniform boiling heat transfer, and the rice in the whole pan can be cooked deliciously.

  In addition, if high temperature steam is supplied in the pan 2 in the pre-cooking process and the cooking process, the temperature in the pan 2 can be raised in a short time. In addition, if high temperature steam is supplied into the pan 2 in the boiling maintenance step, the steam hits the rice bowl, so that spillage can be prevented.

  Moreover, in this Embodiment, although it describes about the case where rice is cooked with an electromagnetic induction heating type rice cooker, the pot heating means may be a heater, and even if the food to be cooked is a heating cooker other than rice. Needless to say, it is good.

  As described above, in the heating cooker according to the present invention, the pan is heated uniformly from the entire bottom of the pan by being heated uniformly, and the entire object to be cooked is heated uniformly by the uniform boiling heat transfer, Since the cooking object in any part of the pan can be cooked deliciously without any variation, it can be applied to various uses such as a heating cooker.

DESCRIPTION OF SYMBOLS 1 Main body 2 Pan 3 Lid 4, 4a, 4b Pan heating means 5 Pan temperature detection means 6 Steam generation means 7 Control means 8 Lid cover 9 Steam path 10 Heating plate 11 Heating plate heating means 12 Heating plate temperature detection means 13 Steam cylinder 14 Steam superheater 15 Packing (first packing)
16 Water tank 17 Water tank heating means 18 Water tank temperature detection means 19 Packing (second packing)
20 Ferritic stainless steel 21 Aluminum 22 Fluorine resin coating X, Y, Z Concavity and convexity A, C Additive particles B Micropores

Claims (6)

An opening is formed on the upper surface, and a plurality of uneven portions are formed from the side surface to the bottom surface. When the inner surface side has a concave shape, the opposite outer surface side has a convex shape on the inner surface side and the outer surface. A cooking device in which a pan having a shape corresponding to the uneven shape on the side and a pan heating means are arranged on the outer surface side where the uneven portion of the pan is not formed. The cooking device according to claim 1, wherein the plurality of concave and convex portions are formed simultaneously when the pan is molded. The pan is formed of a base material made of a magnetic metal, and the plurality of concavo-convex portions are formed on the base material from an arbitrary outer periphery from the substantially middle of the side surface of the pan to the bottom surface and extending to the bottom surface. The cooking device according to claim 1 or 2, wherein the pan heating means is an induction heating coil. The fluororesin coat is formed on the inner surface of the base material, and at least one of silicon carbide and diamond is unevenly distributed as additive particles in the fluororesin coat at the bottom of the concave portion of the base material. The cooking device described. A powder coating in which a fluororesin coat is formed on the inner surface of the base material, and at least one of silicon carbide and diamond is microencapsulated as additive particles on the fluororesin coat at the bottom of the recess of the base material The cooking device according to claim 4, wherein is unevenly distributed. Forming a fluororesin coat on the inner surface of the substrate, forming a plurality of polygonal pyramid-shaped micropores in a surface layer of the fluororesin coat other than the concavo-convex portion, and the additive particles are unevenly distributed on the surface of the fluororesin coat And the cooking device according to claim 4 or 5, wherein the most present at the lowermost part of the fine hole.

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