JP2007296262A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker capable of maintaining the taste of freshly boiled rice even if warmed for a long period of time because of its stable moisture keeping and gas absorbing performance. <P>SOLUTION: The rice cooker comprises a rice cooker body, a pot to be housed therein, heating means for heating the pot and a lid for covering an opening in the upper part of the cooker body. The lid comprises inorganic porous moldings, which have moisture absorbing and releasing and ethylene gas absorbing property and contain 20 to 98 wt.% of an inorganic porous material, on the inside surface facing the interior of the pot. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-retaining rice cooker that can maintain the flavor of freshly cooked rice during heat retention after cooking.

  Freshly cooked rice contains an appropriate amount of moisture, so it has a plump texture and is very delicious. However, if the temperature is kept at a temperature of about 72 to 74 ° C., moisture is discharged from the surface of the rice and dried with time, so that it becomes hard and has a poor taste. In particular, when the lid of the rice cooker is frequently opened during the heat insulation, the steam filled in the pan is released to the outside, and there is a problem that the drying of the rice during the heat insulation further proceeds.

  On the other hand, if the temperature is kept at a temperature of about 72 to 74 ° C. immediately after cooking the rice, the components contained in the rice are changed to generate ethylene gas, which emits an unpleasant odor (hereinafter referred to as “warm odor”). Therefore, there is a problem that the taste is impaired.

  Therefore, for the two problems that rice cookers equipped with these heat retaining functions have, a humidity control material and a deodorizing agent are disposed on the inner surface of the lid to prevent the rice from drying during the heat retention and the generated heat retention. Proposals for removing odors have been made (see, for example, Patent Document 1).

JP 7-16148 A

  However, since the humidity control material and the deodorizing agent are arranged side by side on the inner surface of the lid body, the steam on the side close to the humidity control material is well adjusted for water vapor. Although the warm odor of the near-side rice is almost completely absorbed, it causes unevenness in the humidity control effect and deodorizing effect, such as drying and dropping the taste, so it is impossible to maintain the freshly cooked flavor as a whole There was a problem.

  Furthermore, since the effect of the humidity control material and the deodorizing agent is reduced separately, for example, it is often used while the passage of the service life of one side is overlooked, and always maintains a normal function. For this purpose, there is a problem that it takes time and effort for maintenance, for example, it is necessary to check the deterioration of the performance individually.

  The present invention is based on the fact that an inorganic porous molded body having moisture absorption / release properties and ethylene gas adsorptivity is mounted on the inner surface facing the inside of the pan, and stable moisture retention performance and gas adsorption performance can be obtained. The challenge is to provide a rice cooker that can maintain the taste of freshly cooked rice even if it is kept warm.

  In order to achieve the above object, in the invention according to claim 1, a rice cooker body, a pan accommodated in the rice cooker body, a heating means for heating the pan, and an opening at the top of the rice cooker body are provided. The lid is characterized in that an inorganic porous molded body having moisture absorption / release properties and ethylene gas adsorption properties is mounted on the inner surface facing the inside of the pan.

  In the invention according to claim 2, the inorganic porous molded body contains 20 to 98% by weight of the inorganic porous raw material, and the inorganic porous raw material has an average pore radius of 10 to 80% and a maximum moisture absorption rate of 10. In the invention according to claim 3, the inorganic porous molded body has a maximum moisture absorption rate of 10% or more.

  The invention according to claim 4 is characterized in that the inorganic porous molded body is a fired molded body obtained by adding a flux to the inorganic porous raw material and firing at 700 to 1100 ° C.

  In the invention according to claim 5, the inorganic porous molded body contains titanium oxide, and in the invention according to claim 6, the inorganic porous molded body contains a mineral that generates negative ions, and further, In the invention according to No. 7, the surface of the inorganic porous molded body is covered with a breathable coating layer.

  In the invention according to claim 8, an automatic opening / closing port that opens to discharge steam generated inside the pan during high temperature heating and can be closed to prevent leakage of steam inside the pan during steaming or heat retention is provided, The invention according to claim 9 is characterized in that, in order to secure the moisture release amount of the inorganic porous wet molded body, a water supply means for supplying water to the inorganic porous molded body having insufficient moisture absorption is provided.

  In the invention according to claim 1, since the inorganic porous molded body mounted on the inner surface of the lid is excellent in moisture absorption and desorption, the inorganic porous molded body absorbs water vapor generated during rice cooking, and this is gradually absorbed during heat retention. Since it releases and keeps the humidity inside the pan constant, drying of the rice kept warm for a long time can be prevented, and deliciousness can be maintained without losing the freshly cooked texture. In addition, since the inorganic porous molded body can adsorb ethylene gas and the like generated at the time of heat retention, the heat retention odor peculiar to the heated rice is suppressed, so that it is possible to maintain the same taste as freshly cooked. Moreover, since the inorganic porous molded body appropriately dissipates the gas once adsorbed when not in use, it can exhibit a gas adsorbing function semipermanently.

  In addition, since the inorganic porous molded body exhibits moisture absorption and desorption and gas adsorption on the entire surface, the humidity of the cooked rice can be maintained moderately throughout the pan, and a sufficient amount of gas adsorption can be obtained. It is done. Moreover, since the inorganic porous molded body is basically maintained without deteriorating moisture absorption / desorption and gas adsorption, it is maintenance-free and can be easily used by elderly people and the like.

  When an inorganic porous molded body containing 20 to 98% by weight of an inorganic porous material having an average pore radius of 20 to 80% and a maximum moisture absorption rate of 10% or more is used as in the invention according to claim 2, absorption is achieved. A sufficiently large amount of moisture absorption is obtained because the water vapor thus condensed is capillary-condensed, and the ethylene gas once adsorbed can be appropriately dissipated when not in use, so that the gas is not saturated. If the average pore radius is less than 20 mm, the adsorbed gas adsorbed on the inorganic porous molded body is difficult to dissipate, reaches saturation, and is difficult to dissipate water vapor. On the other hand, if it exceeds 80%, capillaries are not condensed, the amount of moisture absorption is small, and the gas adsorption capacity is also low.

  When an inorganic porous molded body having a maximum moisture absorption rate of 10% or more is used as in the invention according to claim 3, the rice can be appropriately moisturized over a long period of time, for example, about 3 days. In particular, in order to ensure sufficient hygroscopicity, it is desirable that the maximum moisture absorption rate is 15% or more.

  As in the invention according to claim 4, when a fired molded body obtained by adding a flux to the inorganic porous raw material and firing at 700 to 1100 ° C is used, a high-strength molded body is obtained. In addition to excellent properties, there is no elution of raw material components, so that safe and stable performance can be obtained.

  As in the invention according to claim 5, when an inorganic porous molded body containing titanium oxide is used, a photocatalytic effect is exhibited by light irradiation, so that mold and bacteria can be sterilized and a high sanitary state can be maintained. Since the adsorbed ethylene gas is decomposed inside, the gas adsorption effect can be maintained without being diffused. Can be used permanently.

  When the mineral which produces | generates a negative ion is contained in the inorganic porous molded object like the invention which concerns on Claim 6, the function of the negative ion discharge | released inside the pan decomposes | disassembles unpleasant smells, such as ethylene gas.・ Can deodorize. Moreover, the generation of microorganisms can be suppressed.

  When the surface of the inorganic porous molded body is covered with a breathable coating layer as in the invention according to claim 7, the sticking of rice boiled rice (rice cake) generated from rice during cooking is eliminated. A decrease in ethylene gas adsorption can be prevented. In addition, adhesion of contaminants can be suppressed, and even if they adhere, they can be washed immediately, so that a good hygiene condition can be maintained.

  As in the invention according to claim 8, when an automatic opening / closing port that opens during high temperature heating and closes during steaming or heat retention is provided, the required amount of water vapor can be absorbed during heating, and the inorganic porous molded body during steaming or heat retention. The inside is maintained at an appropriate humidity by water vapor released from the water.

  As in the invention according to claim 9, when a water supply means for supplying water to an inorganic porous molded body having insufficient moisture absorption is provided, an appropriate amount of moisture release is ensured even when the temperature is kept for a long time. It is possible to keep the taste of freshly cooked rice by preventing the rice from drying.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the rice cooker 1 has a container shape with an open top, and is accommodated in the rice cooker body 2 that is stably placed on a table, a counter, and the like, and the rice cooker body 2. And a lid 5 that covers the upper opening of the rice cooker body 2, an inorganic porous molded body 6 that is attached to the inner surface of the lid 5, and a heating means 4.

  The pan 3 is used to cook rice by adding rice and to keep the cooked rice as it is, and is detachably inserted into the rice cooker body 2.

  In this embodiment, the lid 5 includes an outer lid 5S and an inner lid 5U. The outer lid 5 </ b> S has a shape that is smoothly continuous with the rice cooker body 2, and has a through hole 16 at the center thereof. And this outer lid | cover 5S is attached to the upper part of the rice cooker main body 2 so that it can be tilted by being pivotally attached to the receiving part 11 of the upper edge part of the rice cooker main body 2. FIG. Furthermore, when the key-shaped part 12 provided in the upper edge part which faces the said receiving part 11 of the rice cooker main body 2 engages with the edge part of the outer cover 5S, the outer cover 5S is locked to the rice cooker main body 2 upper part. .

  The inner lid 5U has a substantially disk shape and is formed with substantially the same diameter as the upper edge portion of the pan 3, and has a small-diameter short ring-shaped inner piece 23U formed by hanging from the lower surface, and a concentric and large-diameter short piece. And an annular outer piece 23S. A ring-shaped packing 13 is attached to the outer peripheral edge portion of the inner lid 5U, and is detachably attached to the lower surface of the outer lid 5S by the engaging portion 14. As described above, when the outer lid 5S is locked to the rice cooker body 2, the inner lid 5U comes into close contact with the upper edge portion of the pan 3 through the packing 13, so that the inside of the pan 3 is sealed.

  The inner lid 5U has a continuous through hole 15 formed in the center of the inner piece 23U, and the through hole 15 is arranged to face the through hole 16 of the outer lid 5S. As shown in FIG. 2, the through-hole 16 has an upper collar 18U and a lower collar 18D having a small hole 17 of about 2 to 6 mm in the center, the upper and lower ends are blocked, and the upper collar 18U and the lower collar 18D. A sphere 19 having a diameter larger than that of the small hole 17 is inserted therebetween. Thus, at the time of high temperature heating, as shown in FIG. 2, since the ball 19 is pushed up by the water vapor pressure generated in the pan, the water vapor discharge path 20 through the through hole 15 and the through hole 16 is formed. Since the water vapor pressure is lowered during the heat retention, the ball 19 closes the small hole 17 inside the pan of the lower bowl 18D, so that the automatic opening / closing port 7 for preventing leakage of water vapor is configured. Providing such an automatic opening / closing port 7 is preferable in that the inside of the pan 3 can be maintained at an appropriate humidity.

  The heating means 4 includes an induction heating coil that heats the pan 3. In this embodiment, the heating means 4 includes a bottom heating means 4 </ b> T and a side surface heating means 4 </ b> S provided on the bottom and side surfaces of the rice cooker body 2. This has been illustrated. In addition to this, a lid heating means (not shown) may be provided on the outer lid 5S to heat the pot 3 from above. These heating means 4 are controlled by a control means 21 including a microcomputer that operates in response to a signal from a switch and a temperature sensor (not shown).

  As shown in FIG. 3, the inorganic porous molded body 6 has a donut shape in which a round hole 22 is formed at the center, and the diameter thereof is slightly smaller than the inner lid 5U. Then, it is attached to the lower surface of the inner lid 5U and fitted between the inner piece 23U and the outer piece 23S. Thus, since the inorganic porous molded body 6 of this embodiment is fitted and attached between the inner piece 23U and the outer piece 23S, it is possible to prevent cracks at the ends and to open and close frequently. This is preferable in that it can be stably attached to the lid 5U.

  The inorganic porous molded body 6 includes an inorganic porous raw material, and is molded into the above-described fixed shape by firing or non-firing. The inorganic porous material has innumerable pores, and water vapor or ethylene gas is adsorbed in the pores. Therefore, the inorganic porous molded body 6 absorbs moisture and releases the absorbed moisture. A reversible moisture absorption / release function and ethylene gas adsorption are born. Note that the switching between the hygroscopic action and the hygroscopic action is manifested by the environmental humidity conditions. At a humidity of 60% RH or higher, condensed water exists in the voids of the inorganic porous molded body, and water vapor constantly flows in and out of the voids like a fountain, so that the water vapor cluster is kept small. It has a negative ion effect. Since the inorganic porous molded body adsorbs various malodorous gases such as not only ethylene gas but also basic gases such as ammonia and acidic gases such as hydrogen sulfide, the generation of malodor can be prevented. In particular, water-soluble gases such as ammonia and formaldehyde dissolve in condensed water in the voids and are adsorbed in large quantities. Ethylene gas is said to be generated when it rots, and is said to be a gas that promotes rot. By adsorbing ethylene gas, rot can be suppressed, so it is possible to prevent rot of rice and keep it fresh. Therefore, delicious rice can be stored for a long time.

  By mounting such an inorganic porous molded body 6 on the inner surface of the lid, a large amount of water vapor generated during cooking is absorbed by the inorganic porous molded body, and the absorbed water vapor is absorbed during steaming and warming after cooking. Slowly release to maintain the inside of the pan at a suitable humidity. Therefore, even if kept warm for a long time, the rice is prevented from drying, so that the deliciousness can be maintained without losing the freshly cooked texture.

  And since the inorganic porous molded object 6 can adsorb | suck in the pore the ethylene gas generated from rice during a heat retention, the heat retention odor peculiar to the heat-retained rice is suppressed. Therefore, the same deliciousness that has been cooked in combination with the anti-drying effect is maintained. Further, when the inorganic porous molded body 6 is not used, the gas adsorbed in the pores is appropriately dissipated, so that the gas adsorbing function is refreshed and the effect is maintained, so that it can be used repeatedly. If the average maximum radius is 10 mm or more, diffusion is possible, but if it is 20 mm or more, gas can be easily diffused and gas can be easily diffused. Some gas reacts and is fixed in the void, but in this case, it is decomposed by the photocatalyst. A gap of less than 10 mm is a problem because it requires a large energy of 100 ° C. or more in order to dissipate.

  Furthermore, since the inorganic porous molded body 6 has moisture absorption and desorption properties and gas adsorption properties over the entire surface, the humidity of the whole rice kept warm inside the pan is maintained moderately and with a sufficient amount of gas adsorption. Is obtained. Moreover, the inorganic porous molded body 6 is maintenance-free because it does not deteriorate moisture absorption and desorption and gas adsorption as described above, and can be handled easily even by elderly people. Furthermore, when the inorganic porous molded body 6 having a maximum moisture absorption rate of 10% or more is used, even if the rice is kept warm for a long time, for example, for about two days, the freshly cooked texture can be maintained without drying the surface.

  As the inorganic porous material used for the inorganic porous molded body 6, those having a maximum moisture absorption rate of 10% or more are effective. In particular, inorganic porous materials with a maximum moisture absorption rate of 15% or more are more effective, such as siliceous shale, allophane, imogolite, sepiolite, activated clay, and Otani stone. It is also good. Among these, siliceous shale and sepiolite are effective because they have a heat resistance of 900 ° C. or higher, and voids are hardly blocked until firing at 1100 ° C. In order to secure a large number of voids, it is desirable to fire at 1000 ° C. or lower.

  When such inorganic porous moisture-conditioning material having a maximum moisture absorption rate of 10% or more is blended in an amount of 20 to 98% by weight based on the whole forming raw material, as described above, the maximum moisture absorption that can keep the rice in a suitable state for a long time. An inorganic porous molded body 6 having a rate of 10% or more can be obtained. If it is less than 20% by weight, the intended humidity control function and the like cannot be obtained sufficiently. On the other hand, if it exceeds 98% by weight, the strength is insufficient, so that cracks are likely to occur, and it becomes difficult to maintain the shape during molding. However, some inorganic porous materials contain clay, and in that case, molding is possible only with the inorganic porous raw material, and a molded plate can be made with only 100% inorganic porous raw material. By blending a large amount, excellent performance can be obtained, and the amount of blending can be increased by devising a binder or the like.

  The inorganic porous humidity adjusting material preferably has an average pore diameter in the range of 10 to 80 mm, and an appropriate void that can be capillary condensed is formed. In the pores of such a size, condensed water is formed in an environment where the humidity is 60% RH or more, so that it has excellent moisture absorption and desorption properties and can absorb ethylene gas well, and the adsorbed gas can be moderately absorbed. Since it can diffuse, it is preferable at the point which is not saturated. If it is less than 10 mm, the voids are too small, so that capillary condensation cannot be performed and the adsorbed ethylene gas cannot be dissipated, resulting in saturation. Since it is more easy to dissipate at 20 mm or more, it is more preferable. On the other hand, if it exceeds 80%, condensed water cannot be formed even in an environment where the humidity is 60% RH or higher, so that moisture absorption and desorption and ethylene gas adsorption are reduced.

  The inorganic porous molded body 6 preferably contains titanium oxide. Titanium oxide generates active oxygen by receiving ultraviolet rays, and it decomposes dirt, bacteria, bad odors, etc. into carbon dioxide and water by its strong oxidative decomposition action, disinfecting, antibacterial, air / water purification, antifouling, deodorizing action Etc. Exhibit the function as a photocatalyst. In a rice cooker, sanitary conditions can be improved by sterilization and antibacterial functions, and a freshly cooked texture can be maintained during long-term heat retention by deodorizing action. When the lid is removed and exposed to sunlight, the adsorbed gas decomposes quickly, and if the lid or the inorganic porous molded body can be removed, it can be used permanently.

  The inorganic porous molded body 6 preferably contains a trace amount of a mineral that generates negative ions typified by monazite. Unpleasant odors are decomposed and deodorized by negative ions generated in the rice cooker during heat insulation, and a sanitary state is maintained by exhibiting a bactericidal action.

  The surface of the inorganic porous molded body 6 is covered with a breathable coating layer. This breathable coating layer is an inorganic coating material obtained by special treatment including alkyl silicate, metal alcoholate, isopropyl alcohol, etc., breathable acrylic resin that imparts breathability to acrylic resin, organic using acrylic silicon resin A functional coating material or the like can be used. Use of such an inorganic coating material is preferable in terms of high hardness and excellent durability. The air-permeable coating layer is a thin film layer that can ensure air permeability, and it is necessary to ensure the absorption / release property and gas adsorption property of the inorganic porous molded body. The inorganic porous molded body 6 covered with the air-permeable coating layer has a moisture absorption / release property and ethylene gas adsorption because the surface of the surface suppresses the adhesion of rice boiled rice (rice cake) generated from rice during cooking. Can maintain sex. Furthermore, even if it becomes dirty, it is preferable in that it can be easily washed and can maintain a high hygienic state.

  The inorganic porous molded body 6 releases the moisture sufficiently absorbed at the time of rice cooking and after rice cooking, so that the inside of the rice cooker is in a humid state even during the heat retention, and the rice is not dried. When the upper lid is opened and closed too much and the rice dries, the wet state can be maintained by replenishing the inorganic porous molded body from the water supply tank T arranged on the back surface of the inner lid 5U. As described above, when the water supply means 8 including the water supply tank T is provided, even when the temperature is kept for a long time, a necessary fixed amount of moisture can be secured, so that drying of the rice can be prevented and the freshly cooked taste is maintained for a long time. be able to.

  When the inorganic porous molded body 6 is molded, clay having plasticity or the like is blended as a binder to ensure green strength at the time of press molding, and a stable product after firing can be obtained. When the strength is insufficient, a flux is added to the inorganic porous raw material and fired at a high temperature of 700 to 1100 ° C. to obtain a hard and high-strength molded body. Although the strength is increased at a high temperature, the voids are preferably fired at 1000 ° C. or lower because the voids are reduced by melting. As the flux, glass powder, alkali salt or the like can be used. Although it does not specifically limit, the flux which does not come out of an elution component from an inorganic porous molded object after baking is preferable. A safe and stable humidity control performance and gas adsorption performance can be obtained with an inorganic porous molded body that is free from wear, cracks, chips, etc., has excellent durability, and does not elute raw material components.

Hereinafter, the production method by firing will be described in detail in the order of steps.
[Mixing process]
As the molding raw material, the inorganic porous humidity conditioning raw material, a plasticizer, a flux, a colorant, and the like are blended. In particular, a flux is not required, but may be blended when the strength is insufficient. Water is added to the molding raw material in which these are blended, and wet pulverization is performed by a ball mill, and uniform pulverization is performed. The hydrolyzed and pulverized raw material may be used as an extrusion molding raw material by a filter press, or granulated powder may be made by spray granulation and drying to be used as a raw material. It is necessary to adjust the moisture content of the raw material so that it can be easily molded.
In particular, it does not specify the manufacturing method.

  As the flux, for example, glass powder, zinc white, or the like is used, and the melting point of the forming raw material is lowered to strengthen the bond between the particles, thereby making a stronger molded body.

  After the inorganic porous material is pressed, it is dried and fired to obtain an inorganic porous molded body 6. It may be a semi-wet press molding method using a raw material of granular powder, or may be pressed after being extruded by a vacuum kneader using a filter-pressed raw material. The firing temperature is preferably 700 to 1100 ° C. More preferably, the range of 800 to 1000 ° C. is desirable. If it is less than 700 degreeC, intensity | strength is insufficient and an elution component will also elute. On the other hand, when the temperature exceeds 1100 ° C., the voids are closed by melting, and the moisture absorption ability and gas adsorption ability are greatly reduced. Preferably, 800 ° C. or higher, preferably 850 ° C. or higher is more preferable in terms of strength and prevention of elution of eluted components. Moreover, 850 degreeC or more is preferable also in order to obtain the inorganic molded object which can use the flux which has the component which is easy to elute, and does not have an eluting component.

  Inorganic porous materials such as amorphous clay, allophane, imogolite, etc. are easily clogged at temperatures below 800 ° C, and partially porous inorganic materials such as siliceous shale and sepiolite have a heat resistant temperature. , About 1000 ° C. is preferable. In particular, siliceous shale is a raw material that is abundantly produced in Hokkaido, Japan, and adsorbs a large amount of basic gases such as ammonia and formalin, and is also preferable because it adsorbs various gases such as acid gases and organic gases. . In addition, it is a natural raw material, but there are variations, but the maximum moisture absorption rate is mostly 10% or more, and if it is good, it has a performance of 15% or more, and the maximum is 25-30%. Some are the most preferred raw materials. The siliceous shale is weakly acidic, and when PH is made neutral by adding glass powder or the like, the acid gas of septic odor is more adsorbed and the effect is great.

  20 to 98% of the inorganic porous raw material and 2 to 80% of the binder component are blended in a weight ratio, and wet pulverized and uniformly blended. As the binder, organic binders such as PVA (polyvinyl alcohol), inorganic plasticizers such as bentonite and clay, etc. are used, and imparting shape retention to the substrate obtained by molding by adding an appropriate amount. Can do. What is necessary is just to select the compounding quantity suitable for the shaping | molding method suitably as the compounding quantity of the said binder. In order to increase the hygroscopicity and gas adsorbability, it is necessary to blend a large amount of inorganic porous raw material. If the blending amount is small, the thickness of the inorganic porous raw material becomes thick and the upper lid becomes heavy, which is a problem. Preferably, when 50% or more is blended, an inorganic porous molded body having a thin thickness and excellent performance can be obtained, and blending 50% or more is a good top lid. As the colorant, it is preferable to use an inorganic material that hardly inhibits moisture absorption and desorption. In particular, the colorant is a problem in appearance and does not need to be used.

As these molding raw materials, powdery granular materials, molded products, or liquid raw materials can be used. It depends on the molding method. In the case of a semi-moist press, it is often used in a granular form, in the case of extrusion molding with a vacuum kneader, a molded product is often used, and in the case of pouring, a liquid raw material is often used. It is not particularly related to the molding method.
[Granulation process]
In the case of semi-wet press molding, granulating after wet pulverization to prepare a granular molding raw material, each raw material component is blended evenly, and uniform emphasis on the mold can be achieved. It is easy to handle and suitable for molding work. The particle size of the granulated product is set to an average particle size of 0.1 to 1 mm. Furthermore, the average particle size is preferably 0.2 to 0.8 mm.

[Molding process]
In the same manner as the tile molding process, the molding is performed by press molding, extrusion molding, cast molding or the like. And it processes on the same conditions using the molding apparatus same as a tile. However, since the preferred moisture content varies depending on the molding method, it is necessary to adjust the moisture content to be suitable before molding. In addition, a molding material having shape-retaining properties can be obtained simply by filling the molding raw material into a mold and drying it.

<Semi-wet press molding>
When using dry press molding in which pressure is applied in a state in which the mold is filled, quality stability and productivity can be improved by granulating the molding raw material. The water content of the granulated product is preferably 13 to 30% by weight. Moreover, it is preferable to set a press pressure to 980-2450 N / cm < ² >. If it is less than 980 N / cm ² , the strength of the inorganic porous molded body 6 is insufficient. Conversely, if it exceeds 2450 N / cm ² , sufficient pores are not formed even when fired, and explosion occurs due to foaming pressure in the firing process. There is a fear.

<Extrusion molding>
When the inorganic porous molded body 6 has a rectangular shape, a rod shape, or the like, it is possible to use extrusion molding that can obtain a continuous molded product by extruding a molding raw material from a die having a predetermined shape at a high pressure. is there. In the extrusion molding, it is preferable to use a wet mixed pulverization of the forming raw material, and then to form a cake plate by dehydrating filter press molding, and then pulverize and use the cake plate. The extruded molded product can be appropriately cut to obtain an inorganic porous molded body 6. In order to obtain high moldability, wet extrusion molding in which the moisture content of the molding raw material is about 25 to 40% by weight is preferable. In this case, the extrusion pressure is set in the range of 98 to 590 N / cm ² . If it is less than 98 N / cm ² , the shape retention of the extruded product tends to be insufficient. On the other hand, if it exceeds 590 N / cm ² , sufficient pores are not formed even when fired, and there is a risk of explosion due to foaming pressure in the firing process.

[Baking process]
The molded product obtained in the molding process is fired at a high temperature using a firing furnace such as a combustion furnace or an electric furnace. The firing temperature varies depending on the raw materials used, the size and shape of the inorganic porous molded body 6, and is, for example, about 700 to 1100 ° C, preferably 800 to 1000 ° C. The firing time is about 1 to 6 hours. Since the molded product is fired at a high temperature as described above, a high-strength molded product is obtained, and thus the inorganic porous molded product 6 has excellent durability. Furthermore, since the raw material components do not elute, the safety is high and the performance is stable. A final treatment is performed on the fired product taken out from the firing furnace after firing, whereby the inorganic porous molded body 6 is obtained.

The specific Example of the inorganic porous molded object 6 and the result of having evaluated the performance are shown.
<Formulation raw materials>
Based on the formulation shown in Table 1, molding raw materials were prepared. Each formulation is expressed in weight percent.
<Preparation of granulated product>
50 kg of the forming raw material based on the above composition was placed in a ball mill, wet-ground for 24 hours, and then spray-dried and granulated to obtain a granulated product having an average particle size of 0.5 mm and a water content of 20%.
<Press molding>
The granulated product was filled in a mold and was dry press molded at a pressure of 981 N / cm ² to obtain a molded body. The shape of the green body is a donut disk shape, and the dimensions are a diameter of 250 mm, a central hole diameter of 50 mm, and a thickness of 10 mm. The molded body was dried at 60 ° C. over 1 hour.
<Baking>
The dried green body was baked at a maximum temperature of 950 ° C. for 2 hours using a roller-herskin to obtain an inorganic porous molded body 6.

<Performance measurement>
While attaching the obtained 5 types of inorganic porous molded objects to individual rice cookers and cooking 7 go rice each, it was kept at 75 ° C. for 48 hours. Further, as a conventional example, a rice cooker not equipped with an inorganic porous molded body was used, and rice was cooked and kept under the same conditions. Evaluators consisting of 10 men and women aged 15 to 70 each sampled six types of heat-treated rice, and performed sensory evaluation on taste. As a result, in Examples 1 to 5, there was no decrease in taste in the cooked rice, an evaluation comparable to that of freshly cooked food was obtained, and the warmed odor was not detected at all. Compared with this, in the rice heat-retained with the conventional rice cooker, the result was that it became hard due to the scattering of moisture, and the flavor was significantly impaired, and most evaluators felt a warm odor. The results are shown in Table 1.

  The above description is an example of the embodiment of the present invention. Therefore, the technical scope of the present invention is not limited to this, and various modifications are included in addition to the above-described embodiment.

It is a longitudinal cross-sectional view which illustrates one embodiment of this invention. It is the principal part enlarged view. It is a perspective view of an inorganic porous molded object. It is an expanded sectional view which illustrates a water supply means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker 2 Rice cooker main body 3 Pan 4 Heating means 5 Lid 6 Inorganic porous molded object 7 Automatic opening-and-closing port 8 Water supply means

Claims (9)

A rice cooker body, a pot accommodated in the rice cooker body, a heating means for heating the pot, and a lid covering the upper opening of the rice cooker body,
The rice cooker characterized in that the lid is provided with an inorganic porous molded body having moisture absorption / release properties and ethylene gas adsorption properties on the inner surface facing the inside of the pan. The inorganic porous molded body contains 20 to 98% by weight of an inorganic porous raw material,
The rice cooker according to claim 1, wherein the inorganic porous material has an average pore radius of 10 to 80 mm and a maximum moisture absorption rate of 10% or more. The rice cooker according to claim 1 or 2, wherein the inorganic porous molded body has a maximum moisture absorption rate of 10% or more.   The said inorganic porous molded object is a baked molded object obtained by baking at 700-1100 degreeC while adding a flux to the said inorganic porous raw material, The any one of Claims 1-3 characterized by the above-mentioned. Rice cooker.   The said inorganic porous molded object contains a titanium oxide, The rice cooker in any one of Claims 1-4 characterized by the above-mentioned.   The rice cooker according to any one of claims 1 to 5, wherein the inorganic porous molded body contains a mineral that generates negative ions.   The rice cooker according to any one of claims 1 to 6, wherein the inorganic porous molded body has a surface coated with a breathable coating layer.   An automatic opening / closing port is provided that opens to discharge steam generated inside the pan during high-temperature heating, and can be closed to prevent leakage of steam inside the pan during steaming or heat retention. Rice cooker in any one of 7. The rice cooker according to any one of claims 1 to 8, further comprising a water supply means for feeding water to the inorganic porous molded body having a shortage of moisture absorption in order to secure the moisture release amount of the inorganic porous wet molded body. vessel.

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