CN108477972A - Micro-wave oven rice cooker based on microwave Meta Materials - Google Patents

Abstract

The invention provides a microwave rice cooker based on metamaterials, which mainly solves the problems of non-uniform direct heating of food and limited heating depth in existing microwave ovens. It includes a non-metal medium container (1) and cover (2), the inner wall of the container (1), the inner bottom and the underside of the cover (2) are all coated with a layer of high temperature resistant non-toxic stable metal material surface with a melting point greater than 500°C (12), the outer wall of the container (1), the outer bottom and the cover (2) are coated with Nuoqian open metal resonant rings (14) that are periodically evenly distributed, and the resonant frequency of each resonant ring is 2.45 GHz. The metal surface, the dielectric layer and the split resonant ring layer constitute a microwave-absorbing metamaterial structure, which absorbs microwave energy and converts it into heat energy. Each resonant ring in the split resonant ring layer is a heat source, and then passes through the metal surface layer Reheat food (11). The invention has the advantages of uniform heating and no electric arc, and can be used for cooking food.

Description

Microwave rice cooker based on microwave metamaterial

technical field

The invention belongs to the technical field of microwave heating, and in particular relates to a microwave oven rice cooker, which converts electromagnetic energy released by a microwave oven into heat energy and can be used for food heating.

Background technique

With the continuous improvement of people's living standards, people gradually get rid of the demand for material quality and turn to the pursuit of quality, and diet is just the most important part of people's daily life. Rice is one of the protagonists in the daily diet of Chinese people. How to cook rice well and quickly has been a problem that China has been exploring for thousands of years.

The cooking methods with higher popularity now include steaming in an electric cooker and direct heating in a microwave oven. A microwave rice cooker is a container for heating rice in a microwave. Common microwave rice cookers on the market are generally made of non-metallic materials such as plastics, pottery and glass. Microwaves generated by microwave ovens can directly pass through non-metallic materials to heat food. Because the thickness of microwave penetration is limited, the amount of rice that can be heated by ordinary microwave rice cookers at one time is limited, and often only two to three servings of rice can be heated, and using ordinary microwave rice cookers to heat rice will cause The rice is heated unevenly, and the rice is relatively dry, with insufficient internal moisture, and the rice has a strong starchy taste, and the use of plastic containers for heating for a long time will cause harm to the human body.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the above existing microwave rice cookers, and provide a microwave rice cooker based on microwave metamaterials, which can evenly heat rice by utilizing the wave-absorbing principle of microwave metamaterials, keep the moisture inside the rice, and avoid plastic Heating the container can be harmful to the human body.

Technical scheme of the present invention is realized like this:

1. Technical principles

With the help of the popular IH rice cooker, the present invention uses multiple electromagnetic induction coils to heat the inner pot, which is equivalent to multiple heat sources heating the rice at the same time. The temperature rises quickly, the heating efficiency is high, the food is heated evenly, and the taste is good. Coating the surface of the metamaterial can achieve uniform heating in the microwave oven, that is, to achieve the effect of simultaneous heating of multiple heat sources, to ensure that the food can reach or exceed the effect of the IH rice cooker, and to avoid the arc of the rice cooker.

2. Technical solution

According to above-mentioned principle, the present invention adopts the container of nonmetallic cylinder shape and cover, it is characterized in that:

The inner wall and the bottom of the inner wall of the container are coated with a layer of high-temperature-resistant, non-toxic and stable metal material with a melting point greater than 500°C. The outer wall layer and the bottom of the outer wall of the container are coated with an open metal resonant ring with a resonant frequency of 2.45GHz. The metal surface and the dielectric layer , The resonant ring constitutes a microwave-absorbing metamaterial, which is used to absorb microwave energy and convert it into heat energy, and then heat food through the metal surface;

The upper and lower parts of the cover are respectively coated with a metal resonant ring with a circular opening with a resonant frequency of 2.45GHz and a layer of high-temperature-resistant non-toxic metal material with a melting point greater than 500°C, forming a closed system with the container to prevent the direct entry of microwaves The interior of the container avoids the danger caused by electromagnetic induction caused by microwaves hitting the metal surface of the inner wall of the rice cooker. At the same time, it absorbs microwave energy and converts it into heat energy, and then heats the food through the metal surface layer, so that the rice cooker treats the food from different directions. For heating, the heating is more uniform.

Preferably, it is characterized in that the metal surface is made of iron.

Preferably, it is characterized in that the metal resonance ring is selected from high temperature resistant copper or iron with a melting point greater than 500°C.

Preferably, it is characterized in that the container material is a ceramic or glass material with a dielectric constant greater than 4 and a melting point greater than 500°C.

Preferably, it is characterized in that the split resonant ring is a circular metal ring with notches.

Preferably, it is characterized in that the inner diameter, outer diameter, opening size and period of the split resonant ring are calculated by the finite difference method and optimized by electromagnetic simulation software.

The present invention has the following advantages:

1. Since the present invention forms a wave-absorbing metamaterial through the metal surface, the dielectric layer and the split resonant ring layer, it can convert microwave energy into thermal energy, and then use the thermal energy to heat food, which solves the problem of limited heating depth of microwave ovens, so heating The amount of food can be larger than ordinary rice cooker.

2. The present invention consists of a container and a cover together to form a fully enclosed structure, which can not only prevent microwaves from directly entering the container, but also avoid the danger caused by electromagnetic induction caused by microwaves hitting the metal surface of the inner wall of the rice cooker, and at the same time enable the rice cooker to move in all directions. Heat food more evenly.

3. In the present invention, since the unit opening resonant rings are evenly distributed on the outside of the entire rice cooker, each unit opening resonant ring is a heat source, and a large number of heat sources can be used to heat food in all directions at the same time, so the heating efficiency is high and the heating is uniform. The taste of the food is excellent.

4. The materials of the present invention are non-toxic and stable materials with a melting point greater than 500°C, which can be used for a long time and are harmless to the human body.

5. The operating frequency of the present invention is selected as 2.45 GHz, which is the operating frequency band of microwave ovens. Selecting this frequency band can make the rice cooker work on all microwave ovens on the market.

6. The dielectric layer material of the present invention is a high dielectric constant material with a dielectric constant greater than 4, and the thickness of the rice cooker can be greatly reduced. At a frequency of 2.45 GHz, the thickness of the rice cooker can be between 2 and 4 mm. The metal surface The thickness of the layer is between 1 and 2 millimeters, and the thickness of the layer of the split resonant ring is between 0.1 and 0.5 millimeters, so the overall thickness and quality of the rice cooker will not be much different from ordinary rice cookers.

7. Since the present invention uses metamaterials to realize the conversion of microwave energy to thermal energy, and provides energy through microwave ovens, it does not need additional circuits and power supplies, which greatly simplifies the design process and processing procedures.

Description of drawings

Fig. 1 is a three-dimensional structural diagram of the present invention;

Fig. 2 is the schematic diagram of the sectional structure of the use state of the present invention;

Fig. 3 is a schematic flow chart of energy conversion of food heated by microwaves in the present invention;

Fig. 4 is a schematic diagram of split resonator ring layers in the present invention;

Fig. 5 is a graph showing the microwave absorption curve of the metamaterial in the present invention.

Specific implementation method

The specific implementation method of the present invention will be described below in conjunction with the illustrations and text. The solutions provided by the present invention are only preferred solutions and are not limited to similar solutions.

Referring to FIG. 1 and FIG. 2 , the present invention includes a container 1 and a cover 2 in two parts. The container 1 is a hollow cylinder with a wall thickness of 2 to 4 mm formed by non-toxic ceramic or glass dielectric material 13 with a melting point greater than 500 ° C. Taking silicon nitride as an example, its dielectric constant is 4.5. High thermal stability and ablation resistance, it is a very popular ceramic material at present. The cover 2 is a circular surface with a thickness of 2 to 4 mm and is formed from a non-toxic non-metallic dielectric material with a melting point greater than 500°C. The diameter and height of the container 1 are considered according to the use requirements, and the diameter of the lid 2 is consistent with the diameter of the container 1 .

The inner wall and inner bottom of the container 1 are coated with a layer of high-temperature-resistant non-toxic and stable metal material surface 12 with a thickness of 1-2 mm and a melting point greater than 500°C. The split metal resonant ring layer 14, as shown in FIG. 4, has a resonant frequency of 2.45 GHz and a thickness of 0.1-0.5 mm. The metal materials of the split resonant ring layer 14 and the metal surface layer 12 are selected from iron, copper or other non-toxic metals with a melting point greater than 500° C. with high thermal stability. In this example, iron is selected as the metal material.

The lower part of the cover 2 is coated with a layer of high-temperature-resistant non-toxic and stable metal material surface 12 with a thickness of 1-2 mm and a melting point greater than 500° C., and the upper part of the cover 2 is coated with a metal resonant ring layer 14 with openings evenly distributed in the Nuoqian period. The resonant frequency of each ring is 2.45 GHz, and the thickness is 0.1-0.5 mm. The metal materials of the split resonant ring layer 14 and the metal surface layer 12 are selected from iron, copper or other non-toxic melting point greater than 500 with high thermal stability. ℃ metal. The metal surface layer, the dielectric layer and the split resonant ring layer constitute a wave-absorbing metamaterial structure, which can absorb the microwave energy radiated on the surface of the resonant ring and convert the microwave energy into heat energy. Each of the split resonant ring layers All the resonant rings are heat sources, which is equivalent to multiple heat sources heating the food at the same time, which can evenly and efficiently heat the food 11, ensuring that the taste of the food is better than that of ordinary rice cookers, as shown in Figure 3.

The lid 2 covers the upper end of the container 1 to form a closed structure. The closed structure can not only fully absorb the microwave energy radiated from the microwave oven to the surface of the rice cooker, but also completely block the microwave energy from directly entering the inside of the rice cooker. Generally, when a metal is placed in a microwave oven, the electric charge on the metal surface will be redistributed due to the electromagnetic field in the microwave oven, resulting in a potential difference and a breakdown arc. However, the metamaterial structure in the present invention will radiate the microwaves on the surface of the resonant ring The energy is absorbed and converted into heat energy, which eliminates the danger caused by putting metal into the microwave oven.

The split resonant ring is designed by electromagnetic field design software HFSS or CST, and accurate results can be obtained by using this software. The specific parameters of the split resonator ring layer 14 include: period, inner and outer radii, and aperture diameter. After determining the dielectric constant and thickness of the dielectric layer 13, these parameters can be calculated by the finite difference method and optimized by electromagnetic simulation software. In this example, silicon nitride with a dielectric constant of 4.5 and a thickness of 4 mm is selected as the dielectric layer 13 of the container 1, the thickness of the metal surface layer 12 is 1.5 mm, and the thickness of the split resonant ring layer 14 is 0.1 mm. After simulation optimization, the opening is determined. The inner diameter of the resonant ring is 8 mm, the outer diameter is 9.6 mm, the length of the opening gap is 1.3 mm, and the interval between each resonant ring is 4 mm.

The working frequency of the rice cooker mentioned above is 2.45GHz, which is determined according to the public frequency bands used by various countries in industry, science and medicine. This frequency band is used for applications in industry and scientific research. Therefore, the actual operating frequency of microwave ovens on the market is 2.45GHz, and using this frequency as the absorption frequency makes the rice cooker suitable for all microwave ovens on the market.

The present invention can be further illustrated by the following test results.

The wave-absorbing metamaterial structure of the present invention is simulated by electromagnetic simulation software, and the reflectivity of the metamaterial to 2.45GHz microwave energy is obtained, as shown in Figure 5, as can be seen from Figure 5, the microwave reflectivity of the present invention at 2.45GHz can reach Below -30dB, it can absorb more than 99.9% of microwaves, indicating that the present invention can completely absorb and convert microwave energy.

The above description is only a preferred embodiment of the rice cooker, and is not intended to limit the rice cooker. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the rice cooker shall include Within the protection scope of the present invention.

Claims (9)

1. a kind of micro-wave oven rice cooker based on microwave Meta Materials, special using the container 1 and lid 2 of nonmetallic cylindrical shape Sign is：

The inner wall of container 1 and inner wall bottom are coated with the fire-resistant nontoxic stable metal material face 11 that one layer of fusing point is more than 500 DEG C, The outer wall layer of container 1 and outer wall bottom are coated with the split-ring resonator 12 that resonant frequency is 2.45GHz, metal covering and medium Layer, resonant ring constitute absorbing meta-material, for absorbing microwave energy, and are translated into thermal energy, then pass through metal faced heating Food；

The upper and lower part of lid 2 is coated with the circular open metal resonant ring 12 and one layer of fusing point that resonant frequency is 2.45GHz respectively Fire-resistant nontoxic metal material charge level 11 more than 500 DEG C, closed system is formed with container 1 together, for stop microwave directly into Enter inside container, avoids microwave from playing the danger for generating electromagnetic induction on the metal covering of rice cooker inner wall and causing, while absorbing micro- Wave energy is simultaneously translated into thermal energy, then by metal faced heating food, rice cooker is made to add from different directions to food Heat, heating are more uniform.

2. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that metal covering 11 selects iron Material.

3. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that metal resonant ring 12 selects It is more than 500 DEG C of heat safe copper or iron with fusing point.

4. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that 1 material of container is to be situated between Fusing point of the electric constant more than 4 is more than 500 DEG C of ceramics or glass material.

5. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that the opening resonance Ring is notched circular metal ring.

6. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that the opening resonance Ring internal diameter, outer diameter, openings of sizes and period are calculated by finite difference calculus and are obtained by electromagnetic simulation software simulation optimization.

7. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that the thickness of metal covering 12 It is 1-2 millimeters.

8. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that split ring resonator layer 14 Thickness be 0.1-0.5 millimeters.

9. the micro-wave oven rice cooker according to claim 1 based on microwave Meta Materials, which is characterized in that the thickness of dielectric layer 13 It is 2-4 millimeters.