JP4993058B2 - Technology that cooks, heats, and thaws by using microwaves in a microwave oven to give ceramics the functionality of heat exchange - Google Patents

Description

The present invention aims at microwave heating of a microwave oven, uses ceramics, coats magnetic ferrite powder on the inside thereof, and is sintered under a glaze. Select a material with high coercive force from the composition of magnetic ferrite, increase the thermal efficiency over conventional microwave oven heating, give the ceramics a constant temperature control function, and can safely cook, heat, defrost and handle Technical

Background technology

There have been many announcements of technologies that heat microwaves using microwaves in microwave ovens, but there are few products that are in widespread use. The ratio of microwaves absorbed by ceramics is in the range of about 25-30%, and most of them penetrate and heat food directly. A conventional container using a magnetic material has a structure in which food is directly irradiated with microwaves. Even if a lid is attached, the container is basically the same as an open type. The microwave energy of the microwave oven is dispersed and released in the cabinet, and there is little effect of effectively using the magnetic material as the heat energy of the microwave, and there is no significant difference in thermal efficiency.
Even when a magnetic material is used, dielectric heating and induction heating are not effectively used as heat energy for heating food.

Many patents have been issued to mix magnetic materials and ferrite with ceramic glazes, but when the mixing ratio of magnetic materials and ferrite is as low as 20% or less, there is a difference in thermal efficiency even if magnetic materials are mixed. Absent. If the blending ratio exceeds 20%, the glaze will be uneven in temperature and easily cracked, resulting in a drawback in durability.
For induction heating to occur, particles made of a magnetic material are bonded to each other and bonded in a thin film shape to generate heat energy for induction heating, and if dispersed individually, thermal efficiency does not increase.
Thermal efficiency will not increase unless the applied magnetic material has a structure that completely absorbs microwaves without directly irradiating the food contained in the ceramic with microwaves.
Control of the Curie temperature of the magnetic material cannot be maintained in a dispersed powder state.

From the beginning, the clay content such as ceramics and earthenware pots that can be used in microwave ovens contains 0.5 to 4.0% of iron. At this time, the microwave of microwave oven, 2.45 GHz, has a transmittance of 70 to 75%. Many microwaves penetrate ceramics and are directly absorbed by food to generate heat. Even if a magnetic material or ferrite is mixed with the glaze, if the ratio is 20% or less, there is no significant difference in transmittance. Dispersing and mixing in the glaze does not lead to factors that increase thermal efficiency.

We have begun to understand that there is a danger of causing chemical reactions such as chemical changes and chemical synthesis when food is directly irradiated with microwaves and heated. In order to avoid food safety and danger, cooking, heating, and thawing that do not absorb microwaves directly into food are required. There are reports such as salt taste changes and chemical changes in nitrate ions in vegetables.

When microwaves in a microwave oven are used to heat a magnetic material or ferrite, the thermal efficiency cannot be increased unless the synergistic effect of dielectric heating and induction heating is used.
In order to increase the effect of eddy current, there is a report that uses a material with high electrical conductivity such as magnetic material or magnetic ferrite and silver of precious metal, but it is reported that the material has high coercive force of 10A / m or more. When no ferrite is selected, no noble metal is required and eddy currents are generated. If a material with high coercive force is selected from the composition of the magnetic substance or magnetic ferrite, induction heating occurs, and the eddy current increases due to the induction of the self-magnetic field by the microwave electric field, increasing the absorption rate of the microwave in the chamber and increasing the thermal efficiency. Can be raised. It is necessary to select a magnetic ferrite having a higher self magnetic field than the electrical conductivity of the noble metal, which is economical and easy to process.

When heating microwave ovens, heat-resistant ceramics are often used. The whole pottery is heated, and when it is taken out after heating, a pan knob or the like is required. There are no ceramics that can be removed safely with bare hands, depending on the position where the magnetic ferrite is applied.

If microwaves are not directly absorbed by the microwave in the microwave oven, the temperature will not increase and the angle of incidence of the microwaves must be at the magnetic material or magnetic ferrite coating surface. If it is not absorbed, neither induction heating nor dielectric heating occurs.
Even if a magnetic material or magnetic ferrite is blended in the bottom of the ceramic, if the microwave direct microwave position is located on the top surface of the microwave oven, the microwave will be reflected on the bottom surface. A space for the incident angle to enter is required. In a container having a large bottom area such as a pan or a dish, the incident angle is determined from the size of the bottom area, and the incident angle through which the microwave enters from the bottom of the container is not obtained. In the case of a structure in which microwaves are radiated from the bottom surface inside the microwave oven, the structure cannot be improved unless the incident angle is maintained on the entire bottom surface of the container.
When food is put in ceramics without a lid and microwaves are irradiated, the magnetic material that permeates the food and is applied to the bottom of the container is rarely heated, meaning that the magnetic material is sintered. Not done.

In order to effectively heat the food contained in the ceramic container, the thermal efficiency increases when most of the heat generated from the magnetic material or magnetic ferrite is released toward the inside of the container. The ceramic structure has a high heat insulation effect, and heat efficiency increases when heat is generated inside the container. If the magnetic material or magnetic ferrite generates heat with a thin film inside the internal glaze, the external ceramics will have a heat insulation effect, increasing the heat efficiency and increasing the heat retention. All ceramics have a lid and a container integrated to increase thermal efficiency. It is preferable to remove the heating method of covering with a film such as saran wrap from the environmental viewpoint.

There are some ceramics in which silicon carbide and carbon-based materials are mixed with clay and glaze, but the temperature rises at a stretch, the temperature rise control is difficult, and it is not suitable for cooking. Some magnetic materials, such as magnetron, are difficult to control temperature depending on the composition, and are difficult to use unless the composition is selected.
In direct heating by a microwave oven, a temperature difference occurs due to a difference in dielectric constant of materials to be heated, and uniform heating and thawing cannot be performed in the same container.

In direct heating by a microwave oven, the entire interior is heated, heat efficiency is poor, and cooking such as cooking and cooking requires a very long time.

There is an optimum heating temperature for food heating in terms of taste and nutrition. Create a taste of cooking, heating and thawing depending on the heating temperature. Heating and thawing is a condition that is indispensable for hygiene management and safety management, but a setting method for adding the optimum cooking temperature as a function to ceramics has not been adopted so far.

In Japan, the penetration rate of household microwave ovens is 95%. In addition, the penetration rate of microwave ovens in convenience stores, restaurants, and catering industries is high. However, the microwave oven has a low energy efficiency for heating the food with respect to the output, and the entire stainless steel plate in the microwave oven is heated, resulting in a large energy loss.
Energy saving measures are a national issue for electricity consumption.
Microwave heating methods include dielectric heating and induction heating using microwaves, but there is no method that uses these two features and uses them as a synergistic effect to increase thermal efficiency. In many heating methods, there are many heating methods that directly irradiate food with microwaves and dielectric heating.
Even if a magnetic substance or magnetic ferrite is used, there are many structures in which microwaves are directly irradiated to food, and this has not led to improvement in thermal efficiency.
In order to increase the thermal efficiency, a magnetic material or magnetic ferrite is applied or brushed on the inside of the entire container to form a thin film, and a structure in which microwaves are not transmitted directly into the food container directly increases the thermal efficiency. In order for magnetic material and magnetic ferrite applied to ceramics to effectively induce induction heating, microwave energy is absorbed into the entire 360 ° ceramics, and the energy effect of induction heating and dielectric heating is large for the first time. The thermal efficiency of the body and magnetic ferrite is increased by taking a structure in which the heat energy of the body and magnetic ferrite is released toward the food inside.
Many kinds of foods with different dielectric constants are processed and processed.
When directly irradiated with microwaves, a temperature difference in heat generation occurs due to the difference in dielectric constant of the material to be heated. During dielectric heating, it has begun to understand that the energy of microwaves causes chemical changes in food composition and chemical synthesis.
When microwaves are absorbed directly into food, chemical changes occur, resulting in taste changes and compositional changes. Depending on the composition, there may be dangers. For safety reasons, avoid heating methods that directly irradiate microwaves. It is desirable.
There is a need for cooking utensils that can be cooked, heated, and thawed without directly irradiating the microwave with food using a microwave oven, and have higher thermal efficiency and durability than directly irradiating the microwave with food. ing.
Therefore, using ceramic with excellent durability, the powder of magnetic material or magnetic ferrite is applied to the entire interior of the ceramic, a thin film of 5 to 20 microns is formed, and the glaze is sintered on it to finish the ceramic. It was.
The magnetic material has a high coercivity, and the optimal Curie temperature for the cooking utensil was selected. In ceramics, a thin layer of magnetic material is formed on the inner surface of the unglazed surface, and the glaze is sintered on top of it. When a 2.45 gigahertz microwave is irradiated onto a magnetic material having a high coercive force, ferromagnetic resonance occurs, increasing the heat generation effect and at the same time amplifying the magnetization. When the magnetic material is irradiated with microwaves, it shows induction heating, the direction of the rotational movement of the electron spin is aligned, and when eddy current loss occurs, the material with strong self-magnetic field becomes larger due to electromagnetic induction by the microwave electric field, and the electron spin Since the frequency is substantially equal to the frequency of the microwave, the magnetic resonance occurs in synchronism, and the thermal efficiency is increased. In order to increase the self-magnetic field induced by induction heating, it is necessary to create a thin film layer of a certain magnetic material, and since the eddy current loss does not occur if the magnetic material is dispersed in clay or glaze, thermal efficiency Does not go up. The thickness of the thin film layer is determined by the particle size of the powder and the thickness of the film, but an eddy current is generated at a thickness of 5 to 20 microns, and ferromagnetic resonance is generated by the coercive force and high thermal efficiency is exhibited.
The coercive force of the magnetic material is preferably 10 A / m or higher.
On the outside of the thin film of magnetic material or magnetic ferrite is a thick layer of unglazed ceramics, making it a highly heat-resistant container. On the other hand, the inside of the container is only a thin glaze that covers the magnetic substance and magnetic ferrite, and has high thermal conductivity efficiency for food.
The Curie temperature of the magnetic material is preferably selected depending on the contents to be cooked, but in the case of many cooking, heating and thawing, it is in the range of 100 to 250 ° C. If you use 80 ℃ for egg dishes, you don't have to worry about burning. In the case of cooking in which the surface is quickly baked, if a temperature of about 250 to 300 ° C. is selected, the surface is quickly burned.
In the case of boiling, 180 ° C to 250 ° C is optimal. Curie temperature becomes maximum specific heat, and selection with high thermal efficiency is possible.
As the ceramic unglazed material and glaze, a heat-resistant material is selected, and high-temperature processing is performed at a sintering temperature of 1,000 to 1,280 ° C.

A microwave oven microwave was not directly applied to the food, and a high thermal efficiency utilization method was investigated.
Conventional ceramics have a microwave transmittance of 70 to 75%, and most of the microwaves are transmitted and absorbed as they are into food.
A 5-20 micron powder of magnetic material or magnetic ferrite with high coercive force is applied to the entire interior of the ceramic container and the inside of the lid, and a glaze is applied on the thin film layer to sinter the ceramic. . When this porcelain is put in a microwave oven, the microwave passes through the outer unglazed portion, is absorbed almost 100% by the magnetic substance or magnetic ferrite, generates heat, and the microwave does not reach the food directly. The heat generation of the magnetic material or magnetic ferrite applied at this time is due to the synergistic effect of the eddy currents of dielectric heating and induction heating on the magnetic ferrite and the microwave absorption effect due to the amplification of the magnetic field by electromagnetic induction of the microwave electric field. Resulting in higher thermal efficiency.
If you put food in a ceramic container, cover it and heat it with a microwave oven, cover it with a film such as saran wrap without covering the ceramic as in the past, and cook, heat, and thaw by direct microwave However, from a certain amount, a fast processing time is obtained and the thermal efficiency is improved. In cooking, cooking time for cooking Japanese, Western, Chinese and other vegetables and fish, meat, cooking rice, steaming gyoza and shumai is shortened, and a lot of cooking can be done in about 3 to 10 minutes.
The interior of the pottery is laminated, so it has high heat retention and can maintain the optimal intake temperature for a long time.

In Japan, a declining birthrate, a nuclear family, and an aging society are progressing, and small-scale cooking is easy and delicious, and safe cooking is desired. In particular, burns and fire accidents due to direct fire are increasing in children, elderly people, and people with physical disabilities. People with physical disabilities and elderly people cannot hold a high-temperature cooked container with both hands, and holding with one hand with bare hands is an element that prevents accidents. Depending on the selection of the location where the magnetic substance or magnetic ferrite is applied, even if it is heated for 10 to 20 minutes in a microwave oven, it can be taken out with bare hands and can be removed safely.
Although the technology for attaching functions to microwave ovens has progressed, microwave ovens with new functions have high selling prices, and on top of that, the output of electricity increases and power consumption is added. By adding functions to the ceramics, it can be used with the output of the conventional microwave oven, greatly expanding the range of use of the microwave oven, making cooking safe and simple at a low cost.
It is a size that fits inside the microwave oven and is divided into capacities for one to many people. A ceramic earthenware pot, one-handed pot, stew pot, cucumber, cup, gratin plate, flat plate and other containers are attached with a magnetic lid. Ferrite was applied to one surface inside the container. For the magnetic ferrite, a material having a high coercive force was selected, the particles were averaged to a size of 10 microns, and a glaze was sintered thereon to finish the ceramic. The incident angle at which the microwave enters the bottom surface of the container is taken, and a structure is adopted in which the microwave is uniformly absorbed by the entire container at 360 °.
Japanese, Western, Chinese, Ethnic food cooking, cooking, cooking rice, steaming, roasting, baking, cooking can be done in a shorter time than direct fires such as gas pots and conventional microwave ovens, there is no fear of burning, open fire Therefore, freezing and thawing and heating are possible in a short time. Directly irradiate microwaves and cover the surface of the container with a film such as saran wrap, which can be heated faster than heating.In addition, a film such as saran wrap is not required each time, and household waste generated from the disposal of the film can be reduced. It is an environmentally friendly system.
For those with physical disabilities, the process of covering the container with film is a difficult element.
Cooking tools such as iron, stainless steel, and aluminum partially reach a high temperature of 300 to 700 ° C. For this reason, oils and fats are easily burnt, and many anionic surfactants are used for cleaning oils and fats. Anionic surfactants are one of the causes of damaging the hormonal balance of living organisms. It is considered as a causative factor of breast cancer and uterine cancer, and how to reduce it as an environmental problem is a problem.
When the optimum cooking temperature is selected for the temperature of the magnetic ferrite, there is no fear of scorching, and the cleaning is simplified and can be processed with water or a hot water bath.
The feature of the ceramics by this structure is that the place where the magnetic substance or magnetic ferrite is not applied, the temperature rise is small, the container is taken out after heating, the magnetic substance is not applied to the mouth such as grips, knobs, and cusps, If a structure in which glaze is sintered to unglazed is taken, there will be a temperature difference from the place where the magnetic material is applied, and even if it is heated in a microwave oven for about 10 to 20 minutes, it can be held with bare hands. If you put a mouth to take out the boiled liquid from the cucumber and pan and make a structure that does not apply magnetic material at that place, the liquid in the boiled state will not boil up because it will not become hot, and it can be safely transferred to another container Can be replaced. When drinking liquid foods such as a cup directly on the mouth, if the place where the cup or the bottom of the cup is raised and a place where no magnetic substance is applied is made, the temperature does not become high, and the place where it hits the mouth has a low temperature. The temperature can be held with bare hands and there is no risk of burns.
When food is put in a conventional ceramic and put in a microwave oven, the pottery and food become thick at the same temperature.
This phenomenon can be explained as a difference in thermal efficiency.
The area where the magnetic material is applied has three layers, and the exterior is covered with unglazed foods, so it has strong heat retention and is hard to squeeze. Tea, herbal tea, puer tea, fillet liquor, and hot water of shochu Ideal for splitting.

The structure of microwave ovens in Japan is not constant, such as a structure that induces microwaves from a magnetron and scatters and irradiates evenly from the top of the cabinet, or a structure that induces food from the bottom. Nearly 80% of the whole has a structure in which microwaves are irradiated from the upper side or center of the side surface, and the microwaves that are passed through while reflecting from the six surfaces inside the cabinet heat the food in the central part. Any microwave oven structure can be used, and a structure that can easily handle cooking, heating, and thawing is desired.
Conventional ceramics have microwaves that pass through and may generate heat even when a magnetic material is applied to the bottom surface. However, when food is added, thermal efficiency is low. Even if a magnetic material or magnetic ferrite is sintered at the bottom of the ceramic, it does not generate heat because it is not absorbed by the magnetic material or magnetic ferrite unless there is an incident angle of microwaves.
If microwaves are not directly absorbed by the magnetic material or magnetic ferrite, neither induction heating nor dielectric heating will occur.
The bottom of the ceramic container is spaced at a certain interval. When the incident angle at which the microwave enters from the bottom is taken, the bottom surface of the ceramic container absorbs the microwave and generates heat, so that a temperature unevenness does not occur.
Recently sold microwave ovens have a structure in which microwaves are irradiated from the bottom. In this case, avoid the structure where the bottom of the container directly hits the bottom of the inside of the microwave oven and keep a certain interval. The microwave spreads evenly and can be heated with little temperature difference.

For food containers, hazardous materials that can be eluted at high temperatures are prohibited for food hygiene purposes. Magnetic materials include ferrites with chromium, ferrites with nickel, and ferrites with cadmium. Ceramics are not household appliances, but materials that cause environmental pollution due to disposal should be avoided. It is necessary to select a magnetic material and a magnetic ferrite material satisfying this condition. Inexpensive and easily available materials are manganese-ferrite, manganese-zinc-ferrite, and the like. Manganese-ferrite and manganese-zinc-ferrite can be effective by selecting a material having a coercive force of 10 A / m or higher.

When the particles of magnetic material or magnetic ferrite to be applied or brushed on the ceramic are large, not only unevenness occurs but also the temperature varies.
The larger the particle size, the greater the thickness required for coating and brushing. There is no significant difference in coating or brushing thickness and temperature rise. Particles are optimally from nanosize to 20 microns. The thickness of the magnetic material or magnetic ferrite is 1 micron or more and becomes high temperature, and the range of 10 to 20 microns from the coated state is easy to process.
At this time, the ratio of the weight of the magnetic material or magnetic ferrite to the ceramic is within the range of 0.5 to 2%, and the effect of heat generation is obtained.
When ceramics are sintered and mixed with clay or glaze, quick thermal efficiency cannot be obtained even if the same weight is added. Manganese-ferrite and manganese-zinc-ferrite are the most expensive ceramic materials, and by using a thin film, production costs can be reduced with low-cost materials. Only after laminating a thin film on the inside of the ceramic and sintering the glaze on it, the microwave is absorbed by the magnetic ferrite, dielectric heating and induction heating occur, the heat energy is released inside the container and the thermal efficiency becomes high, It becomes economic energy.

Means to solve the problem

The penetration rate of household microwave ovens is as high as 95%, and in the dining / mealing scene, a new microwave oven with a high safety function is added, and increasing the heat efficiency leads to energy saving for power consumption. The number of elderly people living alone is increasing year by year, and the unit for making meals in the home is becoming smaller every year in terms of singles, singles, and declining birthrate. There are many requests. In cooking, the smaller the unit of cooking amount, the more difficult it is to stabilize the taste with conventional cooking utensils.
With the aging of the population, the number of elderly living alone has been increasing year by year, and meal delivery has been promoted. However, the economic support environment has become severe. There is a strong need for safe and delicious cooking by the elderly alone, and there is a need for a simple cooking method.
On the other hand, simplification of cooking is required at home due to social participation by housewife labor, and sales of frozen foods, processed foods, and prepared foods are increasing at food stores in mass retailers and department stores.
In frozen foods, thawing was simple and easy when thawing at a uniform temperature, and fast thawing was one of the technical issues in terms of food hygiene management.
At recent academic conferences on microwave research, there have been many successful examples of chemical synthesis and chemical decomposition as new application development using microwaves. What is the convenience of microwaves, not just the effect of heating food? In addition, there is a danger of causing chemical changes in substances, and from the viewpoint of safety, there is a demand for a heating method with high thermal efficiency without irradiating food with microwaves.
Porcelain is a material that does not easily undergo chemical changes when sintered, and has excellent durability. The ceramics have been devised to have a quick temperature rise function and temperature control function.
The experiment was carried out using three types of ceramic pots with lids of the same size.
For one thing, manganese-zinc-ferrite was applied to the entire lid of the earthenware pot and the entire inner surface of the container in the form of particles having an average particle size of 10 microns. The Curie temperature of manganese-zinc-ferrite was 200 ° C., and the thickness of the manganese-zinc-ferrite thin film at this time was 10 to 20 microns. On top of that, glaze was applied and sintered in an electric kettle at 1200 ° C.
For two, glaze was applied to a traditional clay pot without ferrite applied, and for three, 20% ferrite was mixed with glaze in a conventional clay pot and coated in the same electric furnace. .
These three kinds of earthenware pots were put in the same microwave oven 0.5 kW output, and the temperature rise inside the earthenware pot was examined by inserting a thermocouple thermometer. The inside of the clay pot coated with manganese-zinc-ferrite reached 190 ° C. in 50 seconds, but there was no difference in the temperature rise between the clay pot not coated with ferrite and the clay pot mixed with 20% glaze. The inner temperature was 70 ° C and 73 ° C. Obviously, the effect of increasing the temperature of a clay pot coated with manganese-zinc-ferrite and processed into a thin film can be seen.
When the magnetic material is irradiated with microwaves, the internal heat energy is proportional to the temperature 5/2 and the specific heat is proportional to the temperature 3/2. The energy of the magnetic material is amplified as the temperature increases. Magnetization is also amplified in proportion to the 3/2 power of temperature. In order to effectively give this energy to food in a microwave oven, the container has a capped structure, and how to reduce the amount of heat energy released from the container. Ceramics have poor thermal conductivity, and it is difficult for heat energy to be released to the outside. When magnetic ferrite is applied to the inside of the container, it becomes difficult to release heat from the earthenware pot.
Containers that can be used for microwave ovens that use ceramics are all covered with a lid, and all microwaves are absorbed by the lid and the container, so that microwaves do not directly hit foods, so that they can be used with high thermal efficiency.

The water in the 0019 clay pot was put in and the effect was shown

Figure 1

It is.
300 cc of water was placed in three types of clay pots, and the rise in temperature was confirmed.

Figure 1

Shows the temperature rise at that time, and the earthen pot not coated with ferrite and the earthenware pot containing 20% ferrite in the glaze rises quickly, rising to about 70 ° C. in about 130 seconds. However, after that, although the temperature rises gradually, the clay pot coated with a thin film of manganese-zinc-ferrite reaches 70 ° C in about 130 seconds, and it is understood that the temperature rises faster than this time. It was. This phenomenon shows that the ratio of microwaves permeating through the clay pot and directly heating water is high in clay pots that are not coated with magnetic material and 20% magnetic ferrite. The rise in temperature becomes moderate from the rise in temperature. This phenomenon indicates that the temperature does not increase unless the entire clay pot is heated.
On the contrary, when magnetic ferrite is applied and formed into a thin film, the initial temperature rise is slow until the magnetic ferrite absorbs microwaves and the temperature starts to rise, but when the magnetic ferrite thin film reaches a high temperature, it rapidly Shows that the overall temperature rises. Direct microwave heating is effective for an instantaneous temperature rise, but it shows that a thin film coated with manganese-zinc-ferrite has a higher thermal efficiency from a constant temperature rise.
From this phenomenon, it was shown that it is effective for heating that requires large specific heat such as cooking.

The difference in temperature rise at each position inside the clay pot coated with manganese-zinc ferrite was examined.

Fig-2

Put the earthenware pot in the microwave and irradiate it with microwaves, cover the earthenware pot, attach the bottom of the earthenware pot directly to the bottom plate of the microwave oven, and do not take the microwave incident angle from the bottom, microwave heating 2 minutes. The structure of the microwave oven is a structure in which microwaves are irradiated from the upper surface. At this time, the bottom surface inside the earthenware pot had a minimum temperature of 35 ° C., and the temperature rose from about 17 ° C. to about 18 ° C., but other manganese-zinc-ferrite was applied. The place where it was common reached 190 ° C. Judging from this temperature difference, it indicates that the layer coated with manganese-zinc-ferrite absorbs almost 100% of the microwave incident, and microwaves are transmitted from the upper surface of the clay bottle. If this is the case, the bottom of the inside of the container usually has a high temperature rise, but it is in the temperature range where it appears that it has been raised by the overall radiant heat.
Microwaves are absorbed almost 100% by a thin film of magnetic material or magnetic ferrite, indicating high thermal efficiency.
Next, the bottom of the earthenware pot was raised 1 cm, and in order to investigate the possibility of the height of microwave incidence, it was placed in a microwave oven and heated. The temperature of the bottom surface inside the earthenware pot increased less than the side face, and then the height of the bottom of the earthenware pot became the same temperature only after increasing the height by 1 mm and then raising the height by 1.5 cm. It was shown that the heating of the magnetic substance and magnetic ferrite by the microwave oven would vary in temperature rise if the direct microwave incident angle was not maintained. It was shown that if the microwave incident angle is not maintained to make the internal temperature of the whole earthenware uniform, there is no heat generation effect of the magnetic material and uniform and efficient heating cannot be achieved.

Fig.6

Indicates the height required to raise the bottom of the microwave, which can be absorbed by the whole when the container is heated with respect to the microwave oven. The height of the bottom surface at this time, the formula of L, is determined by the width of the microwave oven, the ratio of the long diameter of the bottom of the container and the wavelength of 2.45 GHz, the equation is

Formula

L = 2.5 N / Dcm, and it is necessary to look at the position of L larger from the refraction and reflection of the electromagnetic wave transmitted through the ceramics than the height of L, and the entire heat generation is stable by about 1.5 times the height. Arise.
Clay pot

Fig-3

The height of 7 needs to be 1.5 times higher than the formula, L.

Using the same shape of the earthenware pot used in 0019, the coercive force of manganese-zinc-ferrite, 10A / m, Curie temperature, 110 ° C, 200 ° C, 260 ° C, is applied to the entire surface of the earthenware pan, The glaze was sintered to see the fever effect of the microwave oven.
When 2 minutes passed with the earthenware pot empty, the internal temperature rose to a temperature almost similar to the Curie temperature. At a Curie temperature of 110 ° C., it increased to 105 ° C., to a temperature of 210 ° C. at a Curie temperature of 200 ° C., and to 250 ° C. at a temperature of 260 ° C.
When the Curie temperature of the magnetic material necessary for cooking is selected in the range of 80 to 300 ° C. according to the purpose of cooking, effective thermal efficiency can be obtained, and different Curie temperatures can be used in the same container.

If it is used according to the target temperature of cooking from the temperature rise shown in 0022, it can be used for various types of cooking, there is no need to heat the heater attached to the microwave oven, and the temperature can be adjusted within the same output It has been shown that high temperatures can be obtained. In some cooking, the taste increases when the surface is baked, and in other cases, the taste decreases when the surface is baked. Bird teriyaki, fish, grilled dumplings, pisa, gratin, etc. need to be grilled, and if there is a difference between the surface temperature and the bottom temperature, it will be grilled and finished beautifully, the Curie temperature of the bottom ceramic And by changing the Curie temperature of the top lid. When the ceramic on the bottom is set to a Curie temperature of 200 ° C. and the Curie temperature of the lid is set to 300 ° C., the finish can be finished with the same time. Egg cooked items, fried eggs, steamed tea, pancakes, etc. are low in temperature and need to be heated to the inside. If a ceramic with a Curie temperature of 110 ° C. is selected, cooking can be done without fear of burning. In the case of chawanmushi, when the Curie temperature of 200 ° C. is used, the steaming temperature becomes too high, and the nest enters into the chawanmushi, resulting in an uneven finish. The optimum temperature is 80-110 ° C.
It is desirable to heat herbal tea, black tea, bancha, etc. at a high temperature at a stretch, and many scents can be enjoyed as an effect of extraction at a high temperature. Using a Curie temperature of 200 ° C in ceramics, reaching an early boiling point and taking steaming time, a more delicious heating can be achieved than the conventional method of pouring boiling water or an open flame.
Taste is better than direct microwave heating. When a magnetic substance or magnetic ferrite is heated by microwaves, the heat energy is completely converted into heat by far infrared rays, and the food is heated. There is a difference between heating by induction heating, which directly heats food by microwaves, and heating by far infrared rays, because magnetic ferrite absorbs microwaves. Cooking heating time is much faster.

When ceramics are put in a microwave oven and food is heated, the entire ceramics become hot. It is very difficult for a person with physical disability or an elderly person to take out with a pan knob when using both hands, and it is difficult to balance.
The earthenware pot has a hand-held grip like a one-handed pot. In addition, I made a knob on the lid and a mouth to transfer the liquid to the clay pot.
Clay pot

Fig-3

No. 3 and 1 knob, and 5 transfer port were processed without applying ferrite. Even if this earthenware pan was put in a microwave oven and heated at 0.5 kw for 15 minutes, the temperature rise was 42 ° C., a temperature that could be held with bare hands.
Even in the same container, if a position where no ferrite is applied is provided, a temperature difference occurs and safe use is possible. In particular

Fig-3

If the position of the mouth of 5 becomes high temperature, the boiled liquid will easily bump, and if it is low temperature, it can be safely transferred.
other

Fig.4

6 or 11, 12 of the cup

Fig.5

The same effect can be seen with Nos. 13, 15, 17, and 18.
Even containers with hot liquids can be handled safely.
This phenomenon is caused by making a magnetic substance or magnetic ferrite powder on the inside of the ceramic, applying it as a thin film, and sintering a glaze on it, so that many microwaves are absorbed by the magnetic substance and magnetic ferrite, resulting in good thermal efficiency. Show.

Using the three types of earthenware pots in which the experiment of 0019 was performed, the heat retention test of the boiled water was conducted.
Put 300 cc of water in a microwave oven for 5 minutes, boil, take out 5 minutes, 10 minutes, 20 minutes later, and measure the temperature after 20 minutes, mix the earthen pot not coated with ferrite and manganese-zinc-ferrite into 20% glaze The clay pots that were sintered had almost the same heat retention, and the clay pots that were sintered after forming a thin film layer of manganese-zinc-ferrite showed high heat retention.
The temperature change at this time is

Table-1

Shown in

Table-1

Initial temperature 5 minutes 10 minutes 20 minutes Temperature unit (℃)
No ferrite 98 68 58 38
20% mixed 98 71 61 40
Manganese-Zinc-
Ferrite thin film layer 98 78 72 56
The fact that the heat retaining property is maintained for a certain time after the food is heated indicates that a long time during which the taste is stable is long for an elderly person who eats longer. It becomes an element that satisfies the conditions essential for the stability of the taste of liquid foods such as rice cakes and soups, and prepared dishes.

The difference in the coercive force of magnetic ferrite and the temperature rise of microwave irradiation is that the three types of coercive force of manganese-zinc-ferrite, 5A / m, 8A / m, 10A / m, are made into an average 10 micron powder. Then, 20 g of pure water was put into a test tube for each 10 g, and the output was reduced to 0.2 kw in a microwave oven of 0.5 kw and confirmed by a temperature rise test. A clear difference in coercive force and temperature can be obtained from low output.
In all three types of ferrite, the Curie temperature was 150 ° C. or more, and the time difference to the boiling point was high for materials with high coercive force, resulting in a precise time difference.
5 A / m-43 seconds, 8 A / m-40 seconds, and 10 A / m-37 seconds are the respective boiling times. In microwave heating of microwave ovens, it was shown that the selection of magnetic ferrite increases the thermal efficiency when a material with high coercive force is selected.

The invention's effect

Ceramic clay pots,

Fig-2

Fig-3

This structure has a capacity of 650 cc.
An earthenware pot is composed of a lid and a container.

Fig-2

Apply manganese-zinc-ferrite with a Curie temperature of 200 ° C to the clay pot

Fig-3

An unglazed clay pot is made, manganese-zinc-ferrite, 10A / m average particle of 10A / m average particle is processed with 10 microns, and Curie temperature is different. Applied. The applied thickness was finished to 10 to 15 microns, a glaze was applied thereon, and sintered at a temperature of 1200 ° C. to finish a clay bottle.

Fig-2

Fig-3

Nos. 2 and 4 indicate positions where manganese-zinc-ferrite is applied to the entire earthenware pot.
When the container was covered, the coating was performed in such a structure that the positions of the respective manganese-zinc-ferrites were closely joined.
In addition, clay pots of the same shape were sintered at the same temperature with glaze alone, and manganese-zinc-ferrite, coercive force 10 A / m, Curie temperature 200 ° C., average particle size 10 microns were mixed with glaze at a 20% weight ratio. And we made a clay pot sintered at the same temperature.
As the microwave oven, a device having an adjustment function of 0.5 kw maximum output and 0.2 output was selected. The magnetron irradiates microwaves from almost the center of the top, and the bottom has a rotating plate. The rotating plate can be removed.
The temperature was measured by a thermocouple, and the recording was recorded by a recorder.
3 types of manganese-zinc-ferrite, Curie temperature 110 ° C, 200 ° C, 260 ° C and magnetic ferrite are applied in a thin film on the inner surface of the earthenware pot. The rise in the temperature of a clay pot in which 20% magnetic ferrite was mixed with glaze was examined. With the earthenware pan empty, put it in a microwave oven with a lid, and after 60 seconds, the temperature rise on the inner side is almost the same as the Curie temperature of the clay bottles coated with manganese-zinc-ferrite. The temperature rose to 105 ° C, 190 ° C and 255 ° C. The rise in the temperature of the clay pot in which magnetic ferrite was not applied and the clay pot in which 20% magnetic ferrite was mixed with the glaze was 70 ° C and 73 ° C. There is a difference in the rise in the internal temperature of the earthenware pot, and the thermal efficiency of the earthenware pot with magnetic ferrite applied as a thin film inside the earthen jar can be confirmed, indicating an increase in temperature close to the Curie temperature.
Next, 300 cc of water is put into a clay pot in which a magnetic ferrite Curie temperature, 200 ° C. is applied to a thin film, a clay pot not coated with magnetic ferrite, and a clay pot in which 20% of magnetic ferrite is mixed with glaze. Was measured. The result is

Figure 1

It is.
There was a clear difference in the temperature rise of the water temperature, and the time to reach the boiling point was faster when magnetic ferrite was applied to the thin film, indicating high thermal efficiency. A large temperature change is not seen in the earthenware pot which does not mix | blend a magnetic body, and the earthenware pot which mixed the magnetic body with 20% glaze, and both have the similarity in the form which temperature rises. In order to increase the temperature efficiently, it was shown that a thin film-like magnetic ferrite structure was applied to the inside of the clay pot to increase the thermal efficiency.

The container in which magnetic ferrite and Curie temperature of 200 ° C. were applied to the inside of the earthenware pot and the container and the glaze was sintered thereon was placed in a microwave oven, and the state of the temperature at each position of the earthenware pot was confirmed when irradiated with microwaves.
Remove the rotating plate of the microwave oven, irradiate microwaves for 60 seconds with the bottom of the earthenware pot in direct contact with the bottom plate of the microwave oven, and watch the temperature rise,

Fig-2

The bottom -6 of the earthenware pot shows almost no increase in temperature, and the inside-2 part of the lid of the earthenware pot and the side-4 part of the earthenware pot container have reached 190 ° C. The position of the bottom surface 6 of -2 is coated with a magnetic material, but the temperature rise is 35 to 45 ° C.
If the magnetic ferrite in the lid of the earthenware pot is almost 100% and does not absorb microwaves, the microwave is transmitted to the bottom part and the temperature rises in the magnetic ferrite on the bottom, but the whole earthenware pot The temperature rise is seen only in the range of radiant heat.
From this phenomenon, when magnetic ferrite was applied as a thin film, it was shown that the microwave absorption efficiency was good, and it was possible to heat the food without direct microwave irradiation.

From the experiment of 0028, it is shown that the increase in the temperature of the magnetic ferrite is less likely to be transmitted and heated from the side unless microwaves are directly incident.
Earthenware pot shows that heat efficiency decreases in a structure where microwaves cannot be directly incident even if a magnetic material is applied to ceramics

Fig-3

From the bottom -7, the height at which the microwave was incident and the temperature rise was observed in the same manner as the side surface was measured.

Fig.6

Shows a method of calculating the height at which a microwave of 2.45 gigahertz can enter the center of the bottom surface by placing a container in the microwave oven. The height L that raises the bottom of the container, L is the size of the inside of the microwave oven, and the height L is determined from the ratio of D to the bottom of the container and N.

Formula-1

L = 2.5 N / Dcm.
When D is 30 cm and the bottom N of the pot is 10 cm, the height of L is about 0.84 cm. When the bottom of the earthenware pot is raised to 0.85 cm, microwave 2.45 GHz reaches the position where it is applied to the container, and the temperature rises. In many cases, the transmittance of microwaves is 70 to 75%, and an unglazed ceramic material can be used as it is as a raising material. However, when the experiment was conducted in a clay pot, the increase in temperature was small at the height of the calculated value L, 0.85 cm, and no uniform increase in temperature was observed. Clay pot

Fig-3

When the temperature is confirmed by raising the height of the 6 lower surfaces by 1 mm, the height of 6 that needs to obtain a uniform temperature is from a position 1.3 cm higher than the height of L shown in FIG. About L × 1.5 times.
It was shown that the height of L needs to be 1.5 times or more because it is refracted and reflected when microwaves enter the ceramic.

In the microwave

Fig-2

,

Fig-3

,

Fig.4

,

Fig.5

Each ceramic was put in and the temperature was confirmed. The Curie temperature of manganese-zinc-ferrite used for the ceramics was 200 ° C. Each figure has a structure in which a thin film of magnetic material is applied and a glaze is sintered thereon. In this structure, the magnetic ferrite is applied to a structure in which the microwave does not heat the food inside, and the food contained therein is heated by the thermal energy of the magnetic ferrite. Ceramic lid and container parts

Fig-2

,

Fig-3

2 and 4,

Fig.4

Of 9 and 10

Fig.5

Nos. 14 and 16 indicate positions where manganese-zinc-ferrite is applied to the whole, and when heated in a microwave oven, heat is generated in a short time.
But,

Fig-2

1, 3, 5,

Fig-3

1, 3, 5, 7,

Fig.4

8, 11, 12,

Fig.5

The places where the magnetic ferrites 13, 15, 17, and 18 are not applied are at a low temperature with different rising temperatures. Even if the ceramics shown in each figure are placed in a microwave oven for 15 minutes and heated, the position where the magnetic ferrite is not applied can be held with bare hands and taken out from the microwave oven. The temperature at this time was 38-45 degreeC.

Fig-3

Using a clay pot coated with a magnetic material of manganese-zinc-ferrite and a Curie temperature of 200 ° C. and then sintered, cooking with a microwave oven was performed to see the cooking time. At this time, the output of the microwave oven can be adjusted to 0.2 to 0.5 kW. The capacity of the earthenware pot is 840 cc. The weight of the earthenware pot is 840 g including the lid and the container.
100g of rice, 150g of water
Rice. 200g, water 300g
Boil at 270 seconds at 0.5 kW, switch to 0.2 kW at the same time as boiling, heat and take out with low heat for 360 seconds, and finish ready to eat in 360 seconds of steaming time. The microwave oven time is 10 minutes 30 seconds. The time to completion is 16 minutes 30 seconds.
Rice was cooked without washing and washing the milled rice on the spot. The time published in the conventional microwave rice cooker manufacturers is 20 to 30 minutes, and it can be finished in about 1/2 to 2/3 of the time. With 100g and 200g of rice, the amount is doubled, but there is no time difference. Especially, it can be cooked immediately after washing, and the steaming time is steamed without lowering the temperature of the earthenware pot, and the heat efficiency is high.
The taste is very good and the cooking is solid.
Meat potato beef 100g, potato 200g, onion 80g,
Carrot 50g, indexed juice 100g
Capacity 530g
In potatoes, an average of 100 g is cut into 1/4 cuts at 0.5 kW for 240 seconds, and the juice is boiling. Potatoes and carrots jumping out of the index soup are already ready to eat, but time is needed in the index soup. Once the whole is mixed in this time, it can be finished in 240 seconds. When 180g of index juice is put and boiled in the liquid, it can be finished in about 10 minutes. In a cooking book using a conventional microwave oven, the average is 15 to 18 minutes, and cooking can be performed in a time of 5.6 / 10 to 2/3.
The taste of potatoes and carrots is good and boiled plumply.
Parent and child udon using frozen udon
1 piece of frozen udon noodles, 1 egg, chicken breast 80g, green onion 30 chopped onion 40g, index 200g
Frozen udon was placed in the bottom and indexed, and then chicken, onion and leeks were placed on top of it and heated.
Boils in a microwave oven of 0.5 kW in 240 seconds, puts out the egg, switches to 0.2 kW, and cooks in 2 minutes.
The grip part and lid knob are not hot when taking out and can be processed with bare hands as it is, which is very convenient.
Frozen udon has a firm waist, and pot-baked udon is finished in a short time.
Yakidon Sweet potato 350g Cut the length in half
Potato 380g Average 95gx4
Sweet potatoes are finished in 4 minutes and potatoes are finished in 4 minutes 30 seconds. In the conventional cooking of a microwave oven, the average time is 10 to 15 minutes, and shortening the cooking time, which is a considerable reduction in time, indicates good thermal efficiency and energy saving.
There is no fear of scorching in any cooking, and washing after ingestion can be washed clean with water, eliminating the need for an anionic surfactant. Saran wrap is not used.
Eco-friendly cooking is possible.

Fig-3

In the earthenware pot, the lid was set at a Curie temperature of 260 ° C., the container was set at a Curie temperature of 200 ° C., gratin rice was put in, and it was confirmed whether or not the baking marks were formed at the same time.
Gratin rice put 200g of frozen food pilaf, put a little cheese powder and melted cheese and butter on top of it and put it in a microwave oven for 300 seconds for 0.5kw. It was ready to eat as gratin rice. The lid temperature and the container temperature change at the same time, and effective cooking is possible.

Fig.4

The cup was covered with a cap, and the capacity of the vessel, 200 cc, manganese-zinc ferrite, and a Curie temperature of 200 ° C. were applied to the inside, and cauterized and water were put in a ratio of 4: 6 in a ratio of 4: 6. The position where 150cc was put

Fig.4

The position is slightly below the 11th line.
When 120 seconds passed in the microwave oven of 0.5 kw, the temperature of the shochu was 70 ° C. But where to put a mouth,

Fig.4

11 and lid knob 8 and bottom 12 were held with bare hands, and the temperature was 38 ° C.
Even if you put a cup in your mouth, you will not have to worry about getting burned. The temperature of shochu is about 45 ° C after about 20 minutes, and in a normal cup, the temperature drops from the same temperature to 45 ° C after 10 minutes. A difference of about 10 minutes or more occurred in the time difference, and it was proved that the heat retaining property is high and the taste can be enjoyed for a long time.
Cooked a bowl of chawanmushi in the same container. When the amount of material was 150 cc and 0.5 kW was observed for 150 seconds, it was found that the nest was in place and the temperature became too high. Next, when the output of the microwave oven was 0.2 kW and 180 seconds passed, tea fumigation was completed. The optimum temperature for chawanmushi is 70-75 ° C. It was shown that continuation of the optimum temperature is a delicious knack, and it is desirable to cook at the same temperature slowly rather than heating at once, but it is possible to balance the output. In addition to using materials with different Curie temperatures, it was shown that the temperature can be balanced by adjusting the output.
Chawanmushi also needs heat retention, and when it gets cold, the taste decreases. The temperature after 20 minutes was maintained at 45 ° C. The optimal intake temperature is kept long.

Fig.5

The earthen jar had a capacity of 650 cc, a manganese-zinc ferrite Curie temperature of 200 ° C. was applied to the lid and the inside, and a glaze was sintered thereon. The sintering temperature was 1250 ° C. and the structure withstands high temperatures.
When 450 cc of water is added and heated in a microwave oven of 0.5 kW, it boils in 250 seconds. At this time, the temperature of the lid knob 13, 15 as the lid, the mouth 18 of the earthen bottle, and the bottom 17 is 38 to 42 ° C. Even if the hot water boiled from the earthenware bottle is transferred to another vessel, it can be poured without sudden boiling, and can be worked directly with bare hands. You can enjoy tea safely and quickly.
It is ideal for boiling tea such as puer tea, chai, and herb tea, and it has high heat retention even when taken out from the microwave, so you can enjoy the scent for a long time.

Originally, ceramics have been used as containers in a long history. New porcelain coated with magnetic ferrite and sintered can be easily cooked for many uses by the user's method of use.
Ceramics can be used as cooking utensils.
It is simple and can be used for a wide range of applications, and on top of that it can be cooked with a small amount of taste. In the EU, dangers are pointed out due to changes in the composition due to heating in the microwave oven, and it is not as popular as Japan and the United States.
The new heating method using magnetic ferrite, when viewed as a tool, avoids the dangers pointed out by the EU, scientifically derives the value of freshness, and can be heated instantaneously, so it is economically economical It is also a highly valuable development.
Cooking is completed in a short time with much lower output than electromagnetic cooking equipment currently sold as the highest in thermal efficiency.
In terms of safety, there are no concerns about chemical changes in ingredients or fires and burns rather than open fires, and handling makes it possible to hold ceramics with bare hands, making it ideal for people with physical disabilities and the elderly. .
Above all, simple and delicious cooking of small amounts is an indispensable cooking method in an aging society in the 21st century.
There is a strong possibility that it will become a major pillar to eliminate the difficulty of home delivery business for elderly single-living families.

電子レンジのなか陶磁器を入れたときに陶磁器の底面にマイクロ波が入射出来るために底面を上げる高さの計算を示す図である。マイクロ波２．４５気かヘルツの場合は庫内の底からＬの高さを上げる必要があり、その場合は庫内の幅と陶磁器の底の底面の長径の比から割り出し、Ｌを計算する。Ｄは電子レンジの幅を示し、Ｎは容器の底の直径を示す。 Using the same unglazed earthenware pot, three different types of earthenware pots were put, 300 cc of water was put in, a microwave oven, the time and temperature until boiling in 0.5 kW were measured with a thermocouple and recorded by a recorder. 1. 1. A magnetic material is manganese-zinc-ferrite, a Curie temperature of 200 ° C., a coercive force of 10 A / m, an average particle size of 10 microns, an average thickness of 10 to 20 microns, and a clay pot sintered with glaze. 2. An earthenware pot with glaze applied to the unglazed pottery. Mixing the glaze with manganese-zinc-ferrite, Curie temperature of 200 ° C, coercive force of 10A / m, average particle size of 10 microns, 20% by weight. Shows goodness and energy saving.

It is a figure which shows the calculation of the height which raises a bottom face in order that a microwave can inject into the bottom face of a ceramic when a ceramic is put in a microwave oven. In the case of microwave 2.45 ki or hertz, it is necessary to increase the height of L from the bottom of the cabinet. In that case, L is calculated from the ratio of the width in the cabinet and the major axis of the bottom of the bottom of the ceramic. . D indicates the width of the microwave oven and N indicates the diameter of the bottom of the container.

Claims (2)

The entire ceramic container interior and lid interior are made of powdered magnetic material and magnetic ferrite, bonded in a thin film layer so that the particles are bonded together, applied under glaze, and sintered ceramics are electronic When microwaves are heated by a microwave in the range, the microwaves are absorbed in the magnetic material and magnetic ferrite, the direction of the rotational movement of the electron spins is aligned, the magnetization is amplified, and the microwaves are applied to the thin film layers of the magnetic material and magnetic ferrite. Since the self-magnetic field is induced by electromagnetic induction due to the electric field, induction heating and heating due to eddy current loss occur, and the frequency of the microwave and the frequency of the magnetic substance and magnetic ferrite are almost equal and tuned. A method of cooking, heating, and thawing inside ceramics that generates heat, adds heat exchange, and increases heat generation efficiency. 2. The method according to claim 1, wherein microwaves are absorbed by the magnetic substance and magnetic ferrite, so that the heat is converted into far infrared rays, and the entire radiation is radiated inside the container to perform cooking, heating and thawing.

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