CN113455914A - Magnetic conduction heating structure and cooking utensil - Google Patents
Magnetic conduction heating structure and cooking utensil Download PDFInfo
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- CN113455914A CN113455914A CN202110975335.5A CN202110975335A CN113455914A CN 113455914 A CN113455914 A CN 113455914A CN 202110975335 A CN202110975335 A CN 202110975335A CN 113455914 A CN113455914 A CN 113455914A
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 175
- 238000010411 cooking Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 206
- 239000010935 stainless steel Substances 0.000 claims description 26
- 229910001220 stainless steel Inorganic materials 0.000 claims description 26
- 229910000838 Al alloy Inorganic materials 0.000 claims description 18
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 10
- 229910052802 copper Inorganic materials 0.000 claims description 10
- 239000010949 copper Substances 0.000 claims description 10
- 230000005284 excitation Effects 0.000 claims description 4
- 230000035699 permeability Effects 0.000 claims description 4
- 230000017525 heat dissipation Effects 0.000 claims 2
- 230000007547 defect Effects 0.000 abstract description 4
- 238000013461 design Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 9
- 235000013305 food Nutrition 0.000 description 8
- 241000209094 Oryza Species 0.000 description 7
- 235000007164 Oryza sativa Nutrition 0.000 description 7
- 235000009566 rice Nutrition 0.000 description 7
- 238000012546 transfer Methods 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 230000005674 electromagnetic induction Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000004088 simulation Methods 0.000 description 3
- 108700041286 delta Proteins 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000020169 heat generation Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 230000036760 body temperature Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000013100 final test Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J36/00—Parts, details or accessories of cooking-vessels
- A47J36/02—Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/004—Cooking-vessels with integral electrical heating means
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/08—Pressure-cookers; Lids or locking devices specially adapted therefor
- A47J27/086—Pressure-cookers; Lids or locking devices specially adapted therefor with built-in heating means
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Abstract
The invention provides a magnetic conduction heating structure and a cooking utensil, wherein the magnetic conduction heating structure comprises a plurality of material layers, and the thickness of each material layer meets the following formula:
wherein, the alpha is the equivalent heating coefficient of the magnetic conduction heating structure and the delta1To the deltanThe thickness of the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure is as follows1To said λnThe heat conductivity coefficient from the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure is rho1To the pnThe density of the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure is as follows1To said cnIs magnetic conductiveThe heating structure comprises a heating structure body and a magnetic conduction heating structure body, wherein the heating structure body comprises a first layer material and an n-th layer material, the specific heat capacity of the first layer material to the n-th layer material is from outside to inside, h is the height of the magnetic conduction heating structure, the unit is mm, and a, b and c are constants. The technical scheme of the invention solves the defect of low heating efficiency of the inner pot of the electric cooker in the prior art.
Description
Technical Field
The invention relates to the technical field of cooking appliances, in particular to a magnetic conduction heating structure and a cooking appliance.
Background
The IH electric cooker is a cooking appliance for heating food by an electromagnetic induction principle, energy efficiency is an important evaluation index of basic performance of the electric cooker, and low-energy-efficiency products are gradually eliminated. Since the energy efficiency of the IH rice cooker is generally higher than that of the heating plate rice cooker, high energy efficiency products represented by the IH technology have become a major trend in the development of the rice cooker industry.
The IH electric cooker has the working principle that: the coil panel at the bottom of the pot body inputs high-frequency alternating current, the current flows through the excitation coil to generate an alternating magnetic field, the alternating magnetic field acts on the inner pot with the magnetic conduction layer, and magnetic lines of force generate induction eddy current in the inner pot to generate eddy current heat to heat food in the pot and the pot. The traditional IH rice cooker inner pot is generally compounded by magnetic-conductive stainless steel, aluminum alloy or copper and other materials, wherein the magnetic-conductive stainless steel is used as an eddy current heat generation layer and mainly has the function of generating heat in an alternating magnetic field to provide heat for the inner pot. The aluminum alloy and the copper material are used as high heat conduction layers, the heat conduction coefficients are high, and the high heat conduction layers can quickly and uniformly transfer heat generated by the magnetic conduction stainless steel layers to all parts of the inner pot.
When the inner pot is designed, if the high heat conduction layer of the inner pot is too thin, the heat transfer speed is slow, and the problems of local overheating and uneven heating can occur. If interior pot high heat-conducting layer is too thick, will heat interior pot body earlier before eating the material with the heating, interior pot itself can absorb a large amount of heats, causes the waste of heat, and rate of heating is slow, leads to heating efficiency lower, and leads to the material extravagant, increases material cost. However, the prior art lacks a design method for a high-efficiency inner pot, which causes the problem that the inner pot of the current electric cooker has lower heating efficiency.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defect of low heating efficiency of the inner pot of the electric cooker in the prior art, thereby providing a magnetic conduction heating structure and a cooking utensil.
In order to solve the above problems, the present invention provides a magnetic conductive heating structure, which includes multiple material layers, wherein the thickness of each material layer satisfies the following formula:
Optionally, α and the heating efficiency of the magnetic conduction heating structure are converted by the following relationship: eta 0.8793 alpha3-2.175α2+1.8032 α + 0.4305; wherein the η is a heating efficiency of the electrothermal heating structure, and the α is in a range of 0.4 to 1.1.
Optionally, a is 0.1, b is 7, and c is 0.5.
Optionally, the thickness of the first layer of material from the outside to the inside of the magnetic conduction heating structure is obtained by the following formula:
wherein, the delta1The thickness of the first layer of material from outside to inside of the magnetic conduction heating structure is in mm,f is the excitation frequency of the coil in Hz, and μrThe relative permeability of the first layer of material from outside to inside of the magnetic conduction heating structure is described as mu0The magnetic conductivity is vacuum magnetic conductivity, the value is 4 pi multiplied by 107H/m, and the sigma is the electric conductivity of the first layer material from the outside to the inside of the magnetic conduction heating structure, and the unit is S/m.
Optionally, the magnetic conduction heating structure is an inner pot of the cooking appliance.
Optionally, in the multiple material layers, the outermost material layer is made of stainless steel, and the rest of the material layers are made of aluminum alloy or copper.
Optionally, in the plurality of material layers, the thickness of the outermost material layer is in a range of 0.3 to 1.4mm, and the total thickness of the rest of the material layers is in a range of 0.6 to 2.7 mm.
Optionally, the material layers comprise a first material layer (10) and a second material layer (20) which are arranged in sequence from outside to inside, the thickness of the first material layer (10) is in the range of 0.3 to 1.4mm, and the thickness of the second material layer (20) is in the range of 0.8 to 2 mm.
Optionally, the material layer further comprises a third material layer (30), the third material layer (30) being located inside the second material layer (20), the thickness of the third material layer (30) being in the range of 0.3 to 1 mm.
The invention also provides a cooking appliance which comprises the magnetic conduction heating structure.
Optionally, the cooking utensil is an electric cooker or an electric pressure cooker, the cooking utensil comprises a pot body and a pot cover, the pot cover is covered on the pot body, a coil panel is arranged at the bottom of the pot body, the cooking utensil further comprises an inner pot (100), the inner pot (100) is placed in the pot body and located above the coil panel, and the inner pot forms the magnetic conduction heating structure.
The invention has the following advantages:
by utilizing the technical scheme of the invention, the material thickness, the material characteristics and the heating efficiency of different magnetic conduction heating structures are recorded and tested, and an equivalent heating efficiency model is established. When the magnetic conduction heating structure is designed, the heating efficiency and the material characteristics of the target magnetic conduction heating structure to be designed are substituted into the equivalent heating efficiency model, so that the material thickness of the magnetic conduction heating structure meeting the target heating efficiency can be designed, and the magnetic conduction heating structure is ensured to have higher heating efficiency. Meanwhile, the material thickness of the magnetic conduction heating structure is designed through the equivalent heating efficiency model, and the method has the characteristics of fast design and high efficiency. Therefore, the technical scheme of the invention overcomes the defect of low heating efficiency of the inner pot of the electric cooker in the prior art.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 shows a schematic structural diagram of a magnetic conductive heating structure of the present invention;
FIG. 2 shows an enlarged schematic view at A in FIG. 1; and
fig. 3 shows a schematic thermal efficiency diagram of different inner pots designed according to the design method of material thickness of the magnetic conduction heating structure of the present invention.
Description of reference numerals:
10. a first material layer; 20. a second material layer; 30. a third material layer; 100. an inner pot.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The method for designing the material thickness of the magnetic conduction heating structure in the embodiment includes:
step S1: according to the material thickness, the material characteristics and the heating efficiency of different magnetic conduction heating structures, an equivalent heating efficiency model is established through experiments;
step S2: and substituting the heating efficiency of the target magnetic conduction heating structure and the characteristics of the material of the target magnetic conduction heating structure into the equivalent heating model to obtain the material thickness of the target magnetic conduction heating structure.
By utilizing the technical scheme of the embodiment, the material thickness, the material characteristics and the heating efficiency of different magnetic conduction heating structures are recorded and tested, and an equivalent heating efficiency model is established. When the magnetic conduction heating structure is designed, the heating efficiency and the material characteristics of the target magnetic conduction heating structure to be designed are substituted into the equivalent heating model, so that the material thickness of the magnetic conduction heating structure meeting the target heating efficiency can be designed, and the magnetic conduction heating structure is ensured to have higher heating efficiency. Meanwhile, the material thickness of the magnetic conduction heating structure is designed through the equivalent heating efficiency model, and the magnetic conduction heating structure has the characteristics of design blocks and high efficiency. Therefore, the technical scheme of the embodiment overcomes the defect that the heating efficiency of the inner pot of the electric cooker in the prior art is lower.
The material properties of the magnetic conductive heating structure refer to relative magnetic permeability, electrical conductivity, thermal conductivity, density, specific heat capacity, and the like of the magnetic conductive heating structure. When the material of a certain layer of the magnetic conduction heating structure is determined (for example, stainless steel, aluminum alloy, copper and the like are selected), the material can be determined. And testing the material thickness, the material characteristics and the heating efficiency of different magnetic conduction heating structures, and performing function fitting on the test data result to obtain an equivalent heating efficiency model of the magnetic conduction heating structure.
Those skilled in the art can understand that the structure for heating by electromagnetic induction can be used as a magnetic conductive heating structure, for example, the magnetic conductive heating structure can be an inner pot of an IH electric rice cooker or an electric pressure cooker, or a pot tool for an electromagnetic oven, an electromagnetic hot pot, a wall hanging electromagnetic oven heat conducting component, an electromagnetic heating mold heat conducting component, and the like. For convenience of explanation, the design method of the present embodiment is described below with reference to an inner pan, but it is understood by those skilled in the art that the design method described below can be fully applied to the various electromagnetic heating components exemplified above.
As shown in fig. 1 and 2, the inner pan 100 is generally composed of multiple layers of materials, mainly including a vortex flow inducing thermal layer and a high thermal conductive layer. In this embodiment, the inner pot 100 includes a first material layer 10, a second material layer 20, and a third material layer 30. The first material layer 10 serves as an induced eddy current heat layer, is made of magnetic materials such as magnetic stainless steel, and generates heat through electromagnetic induction eddy current to heat the inner pot 100 and food materials in the inner pot 100, and serves as a heating source. The second material layer 20 and the third material layer 30 are used as high heat conduction layers, and mainly adopt materials with good heat conduction performance, such as aluminum alloy, copper and the like.
In this embodiment, the first material layer 10 is generally made of a magnetic conductive stainless steel material, a high-frequency alternating current is introduced into the coil of the IH electric cooker to generate an alternating magnetic field in a space around the coil, and the magnetic conductive stainless steel layer generates an induced eddy current in the alternating magnetic field, and the induced eddy current generates heat as a heat source for the IH electric cooker to heat the inner pot 100 and the food materials in the inner pot 100. The second material layer 20 is a high heat conduction layer, is made of high heat conduction materials such as aluminum alloy and copper, and is used for conducting heat generated by the heat generation layer to the whole inner pot 100, so that the whole inner pot body is rapidly heated, the average pot body temperature of the inner pot 100 is increased, the heat exchange performance of the inner pot 100 and food materials in the pot is enhanced, and the heating efficiency is improved. The third material layer 30 functions as a high thermal conductive layer, the same as the second material layer 20.
The 100 magnetic conduction stainless steel layers of the pot in the IH electric rice cooker induce eddy currents to generate heat, the heat is conducted to the whole inner pot body through the high heat conduction layer, the whole inner pot body is heated up rapidly, the average temperature of the inner pot body is improved, the temperature difference between the inner pot body and the inner pot food is increased, the heat exchange performance of the inner pot and the inner pot food is enhanced, and the heating efficiency is further improved.
The heat transfer speed of heat in the inner pot body mainly depends on the heat conductivity coefficient and the material thickness of the inner pot material, the larger the heat conductivity coefficient and the larger the thickness of the inner pot are, the faster the heat transfer speed in the pot body is, and the more uniform the temperature of the inner pot body is; the heating speed of the inner pot mainly depends on the specific heat capacity, the density and the thickness of the material, the specific heat capacity of the material is smaller, the density is smaller, the thickness is smaller, the heating speed of the inner pot is faster, the temperature difference between the inner pot and food materials in the pot is larger, the heat exchange speed is faster, and the heating efficiency is higher.
Therefore, the equivalent heating efficiency model is obtained by the following three theoretical formulas:
heat transfer resistance of the inner pot body:
calculating heat diffusion in the pot body:
lumped parameter method:
the above three formulas are all conventional theoretical formulas, and those skilled in the art can understand the specific meanings and calculation methods thereof, so that the detailed description is omitted.
Based on a lumped parameter method, through numerical simulation and experimental tests, the influence rule of material thermal resistance, thermal capacity and thermal diffusion on the thermal efficiency is researched, the functional relation of physical property parameters, structural parameters and equivalent heating efficiency of the inner pot material is fitted, and an inventor establishes a high-energy-efficiency inner pot design calculation model, which is concretely as follows:
the equivalent heating efficiency model includes:
in the above formula, α is the equivalent heating rate of the magnetic conductive heating structure, δ1To deltanThe thickness of the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure is lambda1To lambdanThe heat conductivity coefficient, rho, of the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure1To rhonDensity of the first layer material to the n layer material from outside to inside of the magnetic conduction heating structure, c1To cnThe specific heat capacity of the first layer material to the n layer material from outside to inside of the magnetic conduction heating structure is shown, h is the height of the magnetic conduction heating structure, and a, b and c are constants.
It will be understood by those skilled in the art that when the material of a material layer of the inner pan 100 is determined, the thermal conductivity, density, and specific heat capacity of the material can be determined. Meanwhile, the overall height of the inner pot 100 can be determined by design. In the equivalent heating efficiency model described above, the variable is therefore the thickness of each material layer. The equivalent heating rate required by the inner pot 100 is brought into the equivalent heating efficiency model, and the thickness of each material layer of the designed inner pot 100 can meet the target equivalent heating efficiency as long as the thickness meets the equation, thereby ensuring that the designed inner pot has higher efficiency.
Specifically, since the material layers in this embodiment include the first material layer 10, the second material layer 20, and the third material layer 30, n may be 3. Those skilled in the art understand that when the number of layers of the material layer of the inner pan 100 is different, n is taken as a corresponding value.
The applicant obtains a large amount of data through simulation calculation, analyzes the relationship among physical property parameters, structural parameters and heating efficiency of the inner pot material based on simulation data, fits the functions of the density, specific heat capacity, heat conductivity coefficient, thickness and inner pot height of the inner pot material and the equivalent heating efficiency, and verifies through the energy efficiency test experiment of the national standard electric cooker, wherein the larger the equivalent heating coefficient is, the higher the heating efficiency of the inner pot is, namely, the higher the thermal efficiency of the IH electric cooker, and the experimental data of the applicant shows that the heating efficiency of alpha (equivalent heating coefficient) and a magnetic conduction heating structure is not in a linear relationship. And α (equivalent heating efficiency coefficient) and the heating efficiency of the magnetic conductive heating structure are converted by the following relationship:
η＝0.8793α3-2.175α2+1.8032α+0.4305；
wherein η is a heating efficiency of the electrothermal heating structure, and preferably, α is in a range of 0.4 to 1.1. Specifically, when η is greater than 86%, the inner pot has a high performance, corresponding to α of 0.4. And when alpha is larger than 1.1, the value of eta is larger than 1, and obviously accords with the design rule. The final value of α is therefore 0.4 to 1.1.
Specifically, the target heating efficiency η is substituted into the above formula, then the equation set is solved to obtain a specific numerical value of α, then α is substituted into the above equivalent heating efficiency model, and the thickness of each material layer is designed.
For convenience of value taking, the applicant lists several common correspondence relationships between heating efficiency and equivalent heating coefficient:
| equivalent heating efficiency alpha | 0.4 | 0.557 | 0.585 | 0.652 | 0.694 | 0.869 |
| Actual heating efficiency η | 86％ | 91.4％ | 91.5％ | 92.5％ | 92.9％ | 93.2％ |
Specifically, the heating efficiency of the high-efficiency inner pot is usually over 86%, so the equivalent heating efficiency is 0.4. Of course, when the target heating efficiency of the inner pot is designed to be other numerical values, the target heating efficiency is substituted into the formula, and the equation set on the right side of the equation is solved.
Further, for the inner pot to be greater than or equal to the high efficiency inner pot, the target heating efficiency should be greater than or equal to 86%, and the corresponding equivalent heating efficiency should be greater than or equal to 0.4.
Preferably, the parameters a, b and c are specifically: a is 0.1, b is 7, c is 0.5. Of course, the values of the three parameters can be adjusted by those skilled in the art according to the fitting result of the experimental data.
Further, in order to generate heat by induced eddy current, a heating heat source is provided for the IH electric cooker, and the outermost layer of the inner cooker must be made of magnetic conductive stainless steel material, that is, the first material layer 10 is made of magnetic conductive stainless steel material, and the thickness of the magnetic conductive stainless steel material is δ 1. According to the skin effect in the electromagnetic heating process, the thickness delta 1 of the magnetic conduction stainless steel material is not less than the skin depth delta 0, so that the thickness of the first layer material 10 from the outside to the inside of the magnetic conduction heating structure is obtained by the following formula:
wherein, delta1The thickness of the first layer of material from outside to inside of the magnetic conduction heating structure, f is the excitation frequency of the coil, murRelative permeability of the first layer of material from outside to inside, mu, of a magnetically conductive heat-generating structure0The magnetic conductivity is vacuum magnetic conductivity, and sigma is the electrical conductivity of the first layer material of the magnetic conductive heating structure from outside to inside.
As can be seen from fig. 2, the first layer of material from the outside to the inside is the first material layer 10 of the inner pan 100.
The above formula is a conventional theoretical skin depth calculation formula, and delta is calculated by the above formula1Then, the equivalent heating efficiency model is brought in, the thickness of other material layers is adjusted, and the numerical value on the equal-sign right side of the equivalent heating efficiency model is larger than or equal to the target equivalent heating coefficient on the left side, so that the designed inner pot 100 has the characteristic of high efficiency.
As shown in fig. 1 and fig. 2, the present embodiment further provides a magnetic conduction heating structure, where the magnetic conduction heating structure includes multiple material layers, and the thickness of each material layer is obtained by the above design method. Among the above-mentioned multi-layered material layers, the outermost material layer is made of stainless steel, and the remaining material layers are made of aluminum alloy or copper.
Preferably, the applicant designs the inner pot 100 according to the above equivalent heating efficiency model, the design target heating efficiency is 86%, the corresponding equivalent heating coefficient α is 0.4, and the design formula is as follows:
wherein n is 2 or 3.
And the thickness of the outermost material is such that:
wherein, delta0Is the skin depth of the magnetic stainless steel material.
The design rule of the thicknesses of all layers of the inner pot in the embodiment is that the thickness of the magnetic conduction layer on the outermost side is in the range of 0.3-1.4 mm, and when the thickness of the magnetic conduction layer is smaller than 0.3mm, the thickness of the magnetic conduction layer is smaller than the skin depth, so that the magnetic induction effect is reduced. When the thickness of the magnetic conduction layer is larger than 1.4mm, the thickness of the inner pot is too thick, the whole weight is too large, and the heating efficiency cannot be improved. The total thickness of the high heat conduction layer formed by the rest material layers at the inner side of the magnetic conduction layer is in the range of 0.6-2.7 mm, so that the inner pot is ensured to have reasonable thickness.
For the inner pot, two-layer and three-layer structures are common, when the inner pot is of a three-layer structure, the thickness of the material layers of the other two layers except the magnetic conductive layer ranges from 0.8 to 2mm and from 0.3 to 1mm respectively. Of course, the inner pot can be designed to be a structure with four layers, five layers and more layers, but the total thickness of the material layers except the magnetic conductive layer is ensured to be in the range of 0.6 to 2.7 mm.
According to the above design formula and design rule, the applicant designs five groups of inner pots 100, the data of which are:
1. the material layers comprise a first material layer 10 and a second material layer 20 which are sequentially arranged from outside to inside, the first material layer 10 is made of stainless steel, the second material layer 20 is made of aluminum alloy, the thickness of the first material layer 10 is in the range of 0.7-1.6 mm, and the thickness of the second material layer 20 is in the range of 1.6-2.3 mm;
2. the material layers comprise a first material layer 10, a second material layer 20 and a third material layer 30 which are sequentially arranged from outside to inside, wherein the first material layer 10 is made of stainless steel, the second material layer 20 is made of aluminum alloy, and the third material layer 30 is made of copper, wherein the thickness of the first material layer 10 is in the range of 0.3-1.4 mm, the thickness of the second material layer 20 is in the range of 0.8-2 mm, and the thickness of the third material layer 30 is in the range of 0.3-1 mm;
3. the material layers comprise a first material layer 10 and a second material layer 20 which are sequentially arranged from outside to inside, the first material layer 10 is made of stainless steel, the second material layer 20 is made of aluminum alloy, the thickness of the first material layer 10 is in the range of 0.3-1 mm, and the thickness of the second material layer 20 is in the range of 1-2.7 mm;
4. the material layers comprise a first material layer 10 and a second material layer 20 which are sequentially arranged from outside to inside, the first material layer 10 is made of stainless steel, the second material layer 20 is made of aluminum alloy, the thickness of the first material layer 10 is in the range of 0.7-1.3 mm, and the thickness of the second material layer 20 is in the range of 0.7-1.3 mm;
5. the material layer comprises a first material layer 10 and a second material layer 20 which are sequentially arranged from outside to inside, wherein the first material layer 10 is made of stainless steel, the second material layer 20 is made of aluminum alloy, the thickness of the first material layer 10 is in the range of 0.3-0.9 mm, and the thickness of the second material layer 20 is in the range of 1.1-1.7 mm.
After the data of the five groups of inner pots are optimized, the final data of the inner pots to be tested are as follows: a stainless steel 1mm aluminum alloy 2mm two-layer pot, a stainless steel 0.6mm aluminum alloy 1.9mm copper 0.5mm three-layer pot, a stainless steel 0.6mm aluminum alloy 2.4mm two-layer pot, a stainless steel 1mm aluminum alloy 1mm two-layer pot, and a stainless steel 0.6mm aluminum alloy 1.4mm two-layer pot.
The final test results are shown in fig. 3, and the thermal efficiencies of the five groups of inner pots are all higher than the design target of 86%, which shows that the five groups of inner pots have the characteristic of high efficiency.
Preferably, the magnetic conduction heating structure is a pot.
The embodiment also provides a cooking appliance, which comprises the magnetic conduction heating structure. The cooking utensil is electric rice cooker or electric pressure cooker, and the cooking utensil includes the pot body and covers the pot cover of establishing on the pot body, and the bottom of the pot body is provided with the coil panel, and the cooking utensil still includes interior pot 100, and interior pot 100 is placed in the pot body and is located the top of coil panel, and interior pot forms the magnetic conduction heating structure.
Of course, the cooking appliance may be other cooking appliances that perform heating by electromagnetic induction.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (11)
1. A magnetic conduction heating structure is characterized by comprising a plurality of material layers, wherein the thickness of each material layer satisfies the following formula:
wherein, the alpha is the equivalent heating coefficient of the magnetic conduction heating structure and the delta1To the deltanThe thickness of the first layer material to the n layer material from outside to inside of the magnetic conduction heating structure is in mm, and the lambda is1To said λnThe heat conductivity coefficient of the first layer material to the n layer material from outside to inside of the magnetic conduction heating structure is W/(m DEG C), and the unit is rho1To the pnThe density of the first layer material to the n layer material from the outside to the inside of the magnetic conduction heating structure is kg/m3, c1To said cnIs a first layer of a magnetic conduction heating structure from outside to insideThe unit of the specific heat capacity from the material to the nth layer material is kJ/(kg DEG C), the unit of h is the height of the magnetic conduction heating structure and the unit of mm, and a, b and c are constants.
2. A magnetically permeable, heat generating structure according to claim 1, wherein α and the heating efficiency of the magnetically permeable, heat generating structure are converted by the following relationship:
η＝0.8793α3-2.175α2+1.8032α+0.4305；
wherein the η is a heating efficiency of the electrothermal heating structure, and the α is in a range of 0.4 to 1.1.
3. A magnetic conduction and heat dissipation structure as recited in claim 1, wherein a is 0.1, b is 7, and c is 0.5.
4. A magnetically permeable, heat generating structure according to claim 1, wherein the thickness of the first layer of material from the outside to the inside of the magnetically permeable, heat generating structure is obtained by the following formula:
wherein, the delta1The thickness of the first layer of material from outside to inside of the magnetic conduction heating structure is in mm, f is the excitation frequency of the coil and is in Hz, and murThe relative permeability of the first layer of material from outside to inside of the magnetic conduction heating structure is described as mu0The magnetic conductivity is vacuum magnetic conductivity, the value is 4 pi multiplied by 107H/m, and the sigma is the electric conductivity of the first layer material from the outside to the inside of the magnetic conduction heating structure, and the unit is S/m.
5. A magnetic conduction heating structure as claimed in claim 1, wherein the magnetic conduction heating structure is an inner pot of a cooking utensil.
6. A magnetic conduction and heat emission structure as claimed in claim 1, wherein the outermost material layer of the multiple material layers is made of stainless steel, and the rest of the material layers are made of aluminum alloy or copper.
7. A magnetic and heat conducting structure according to any one of claims 1 to 6, wherein the thickness of the outermost material layer in the multiple material layers is in the range of 0.3 to 1.4mm, and the total thickness of the rest of the material layers is in the range of 0.6 to 2.7 mm.
8. A magnetic conduction and heat emission structure as claimed in claim 7, wherein the material layers comprise a first material layer (10) and a second material layer (20) which are arranged in sequence from outside to inside, the thickness of the first material layer (10) is in the range of 0.3 to 1.4mm, and the thickness of the second material layer (20) is in the range of 0.8 to 2 mm.
9. A magnetic conduction and heat dissipation structure as recited in claim 8, wherein the material layers further comprise a third material layer (30), the third material layer (30) is located inside the second material layer (20), and the thickness of the third material layer (30) is in the range of 0.3 to 1 mm.
10. A cooking appliance comprising a magnetically conductive heat generating structure as claimed in any one of claims 1 to 9.
11. The cooking appliance according to claim 10, wherein the cooking appliance is an electric cooker or an electric pressure cooker, the cooking appliance comprises a pot body and a pot cover covering the pot body, a coil panel is arranged at the bottom of the pot body, the cooking appliance further comprises an inner pot (100), the inner pot (100) is placed in the pot body and positioned above the coil panel, and the inner pot forms the magnetic conductive heating structure.
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| CN202110975335.5A CN113455914A (en) | 2021-08-24 | 2021-08-24 | Magnetic conduction heating structure and cooking utensil |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114815413A (en) * | 2022-01-12 | 2022-07-29 | 友达光电股份有限公司 | Antenna module and display device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114815413A (en) * | 2022-01-12 | 2022-07-29 | 友达光电股份有限公司 | Antenna module and display device |
| CN114815413B (en) * | 2022-01-12 | 2023-11-21 | 友达光电股份有限公司 | Antenna module and display device |
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