JP2007236730A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker whose cooking performance is improved with its size and usability being in the same range as before. <P>SOLUTION: The rice cooker has a pot 1, a steam pipe 4b, a lid heating plate 5, a lid heating means 6, a pressure adjusting means 9, a steam generating part 5d and a controlling means 13. Temperature variation of the lid heating plate 5 is suppressed, uneven heating of rice is reduced, gelatinization of starch of rice is promoted and the flavor is enhanced by the cooking method for performing pressure heating and steam heating. Power consumption for evaporating excess water is low and little dew is formed in the installation space by rice cooking. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rice cooker using steam.

  Conventional rice cookers have a soaking process that absorbs water into the rice, a cooking process that heats the absorbed rice to gelatinize the starch in the rice, removes excess water remaining in the pan, and further promotes gelatinization. We perform steaming process to let you cook rice. Among them, there is a rice cooker that performs “pressure rice cooking” in which steam generated in the cooking process of rice cooking is confined in a pan, the pressure is set to 1 atm or more, and rice is cooked at 100 ° C. to 110 ° C. On the other hand, cooked rice in which the pressure in the pan is almost the same as atmospheric pressure will be referred to as “normal cooked rice”.

  However, if the conventional rice cooker cooks white rice in a short time, the upper layer rice in the pan will become a cored rice due to insufficient gelatinization, and the lower layer rice will be rice cake-like rice in an over-absorbed state. There arises a problem that the cooked rice is uneven (hereinafter also referred to as “unevenness”) in the upper and lower layers. This point will be described in detail below.

  In the first place, the energy required for the gelatinization of rice during the rice cooking process is that water supplies the rice as a heat medium. At the beginning of rice cooking, there is plenty of water, but as the cooking process progresses, the water evaporates and decreases, so the upper rice in the pot does not touch the water, so the heat supply becomes insufficient and the gelatinization is insufficient. It is easy to become rice. In normal cooking, to prevent this condition, keep the boiling state until there is no water in the pan, and raise the liquid called `` Oneba '' mixed with water, actually rice starch, to the upper rice. The rice can supply enough heat. Therefore, the process of maintaining a boiling state is required for a long time, and in order to cook delicious rice without unevenness in the upper and lower sides, it is difficult to shorten the cooking time.

  Therefore, the inventors have proposed a rice cooker as shown in FIG. 8 as a solution to such a problem. This rice cooker 21 supplies a predetermined amount of water from a water tank 34 provided on the lid 27 to a steam generator 28 a provided on the lid heating plate 28, and generates steam by a lid heating means 29 that heats the lid heating plate 28. The water supplied to the unit 28 is heated to generate steam, and the generated steam is thrown into the pan 12 from the steam inlet 28b provided in the lid heating plate 28. This steam is heated by the lid heating plate 28 while moving from the steam generating section 28a to the steam inlet 28b, and becomes high-temperature steam having a boiling point of water (100 ° C.) or higher at atmospheric pressure. When high-temperature steam adheres to rice having a temperature lower than 100 ° C., it condenses to generate heat and heats the rice. That is, the heat energy required for proceeding gelatinization of rice starch is supplied to the rice by the pan heating means 23 and high-temperature steam to promote gelatinization.

High-temperature steam condenses on the surface of rice at a temperature lower than 100 ° C. and becomes moisture, giving large heat energy. However, since the heat energy given to rice at 100 ° C. or higher is small, the rice is not dried. Further, instead of heating the water tank 34, water corresponding to the required amount of steam is supplied to the steam generating unit 28a and heated by the lid heating means 29, so that it does not take time to generate steam and at a necessary timing. Steam can be generated and charged, and no new heating means is required.
JP 2005-160918 A

  However, in the rice cooker having the conventional configuration, the steam cylinder 35 having the steam discharge port 31 for discharging the steam to the outside of the machine communicates with the steam hole 30 for discharging the steam in the pan 12 provided on the lid heating plate 28. Therefore, the lid heating means 29 cannot be provided in the portion where the steam cylinder 35 is provided. Therefore, when the lid heating plate 28 is heated to generate steam, the lid heating means 29 uniformly heats the lid heating plate 28 other than the portion where the steam cylinder 31 is provided, and the temperature rises. As a result, the temperature difference between the portion of the lid heating plate where the steam cylinder 31 is provided and the portion where the steam cylinder 35 is not provided is increased, heating unevenness on the rice is increased, and it cannot be cooked deliciously. Had problems.

  This invention solves the said conventional subject, and it aims at providing the rice cooker which improved the rice cooking performance without the unevenness | cooking of cooking in the upper and lower layers in a pan with a pressure and steam.

  In order to solve the conventional problems, a rice cooker of the present invention includes a pan, a pan heating means for heating the pan, a lid for covering the opening of the pan, and a lid heating plate provided on the lid. , A lid heating means for heating the lid heating plate, a steam hole provided in the lid heating plate for discharging the steam in the pan, and a steam provided in the lid for discharging the steam from the steam hole to the outside of the apparatus A cylinder, pressure adjusting means for adjusting the pressure in the pan, a water tank attached to the lid, a steam generator provided in the lid heating plate for storing water supplied from the water tank, and the lid A steam inlet is provided on the heating plate for introducing the steam generated by the steam generating section into the pan.

  During cooking rice, supply a predetermined amount of water corresponding to the required amount of steam from the water tank to the steam generator, and heat the lid heating plate with the pressure in the pan adjusted to the atmospheric pressure or higher by the pressure adjusting means. As a result, the water in the steam generating part rises to the boiling point or higher at atmospheric pressure. Next, when the pressure in the pan is adjusted to atmospheric pressure, the water in the steam generating section boils rapidly and steam is generated, which is heated by the lid heating plate to become high-temperature steam and is introduced into the pan from the steam inlet. When steam adheres to rice at a temperature lower than the boiling point of water, it condenses and generates heat to heat the rice.

  In this way, the heat energy necessary to advance the gelatinization of rice starch is supplied to the rice by the pot heating means at the bottom and steam introduced from above to promote gelatinization. Heat energy can be given to the upper rice without drying, and cooking unevenness occurring in the lower layer and upper layer in the pan can be eliminated.

  In addition, since the water in the steam generating unit rises to the boiling point or higher at atmospheric pressure, the heating amount heated by the lid heating means to generate the steam can be reduced, and the temperature at which the steam cylinder of the lid heating plate is not provided Does not rise excessively, it can suppress the temperature unevenness between the part with the steam cylinder of the lid heating plate and the part without it, reduce the unevenness of heating to the rice, sufficiently promote the gelatinization and deliciously the whole Can be cooked.

  The rice cooker of the present invention can promote gelatinization of rice without drying the rice, and cooks the rice in the pan evenly, thereby improving the rice cooking performance.

  1st invention is a pan, the pan heating means which heats the said pan, the lid which covers the opening part of the said pan, the lid heating plate provided in the said lid, and the lid heating means which heats the said lid heating plate A steam hole provided in the lid heating plate for discharging steam in the pan, a steam cylinder provided in the lid for discharging steam from the steam hole to the outside of the machine, and adjusting the pressure in the pan Pressure adjusting means, a water tank attached to the lid, a steam generator provided on the lid heating plate for storing water supplied from the water tank, and generated by the steam generator provided on the lid heating plate And a steam inlet for introducing the steam into the pan.

  During cooking rice, supply a predetermined amount of water corresponding to the required amount of steam from the water tank to the steam generator, and heat the lid heating plate with the pressure in the pan adjusted to the atmospheric pressure or higher by the pressure adjusting means. As a result, the water in the steam generating part rises to the boiling point or higher at atmospheric pressure. Next, when the pressure in the pan is adjusted to atmospheric pressure, the water in the steam generating section boils rapidly and steam is generated, which is heated by the lid heating plate to become high-temperature steam and is introduced into the pan from the steam inlet. When steam adheres to rice at a temperature lower than the boiling point of water, it condenses and generates heat to heat the rice.

  In this way, the heat energy necessary to advance the gelatinization of rice starch is supplied to the rice by the pot heating means at the bottom and steam introduced from above to promote gelatinization. Heat energy can be given to the upper rice without drying, and cooking unevenness occurring in the lower layer and upper layer in the pan can be eliminated.

  In addition, since the water in the steam generating unit rises to the boiling point or higher at atmospheric pressure, the heating amount heated by the lid heating means to generate the steam can be reduced, and the temperature at which the steam cylinder of the lid heating plate is not provided Does not rise excessively, it can suppress the temperature unevenness between the part with the steam cylinder of the lid heating plate and the part without it, reduce the unevenness of heating to the rice, sufficiently promote the gelatinization and deliciously the whole Can be cooked.

  Moreover, the vapor | steam supplied in a pan can further be heated by a lid | heater heating means, and the temperature of a vapor | steam can be made into the high temperature vapor | steam exceeding the boiling point of water, and can be thrown in in a pan. While the temperature in the pan is 100 ° C or higher in the cooking process of pressure rice, it gives steam to the rice at a temperature of the same level or higher, and the steaming process increases the temperature without lowering the temperature of the rice. It can be maintained. In addition, high-temperature steam at the required temperature can be added according to the type and condition of rice, such as white rice and brown rice, new rice and old rice, and cooked into rice with good taste that is sweet and sticky due to sufficient gelatinization. And rice cooking performance is improved.

  In addition, by generating steam with the lid heating plate and lid heating means, it does not add a dedicated heat source, does not increase the size of the equipment, generates high temperature steam, and further increases the high temperature energy to the rice heated to high temperature at high pressure The necessary amount is supplied at an appropriate timing, and rice cooking performance is stably improved.

  In addition, by controlling the amount of water supplied from the water tank, the amount of steam generated, that is, the amount of steam input can be controlled. By appropriately dividing the water in the water tank and supplying it to the lid heating plate, the lid heating means can heat a small amount of water in a short time with the same heating capacity, and can put this as steam into the pan. . Therefore, an amount of steam necessary for appropriate timing can be put into the pan, and rice cooking performance is improved.

  According to a second aspect of the present invention, in the first aspect of the invention, the pressure adjusting means includes a steam hole provided in the lid heating plate for releasing the steam in the pan, a steam hole opening / closing means for opening and closing the steam hole, and the inside of the pan By detecting the pressure change in the pan due to the amount of steam generated in the pan, such as the amount of rice cooked and water, etc. In each step of cooking rice, it can be controlled to a predetermined pressure and temperature.

  In addition, when the steam hole is opened and closed by the steam hole opening and closing means, the pressure in the pan becomes about the same as the atmospheric pressure, steam is generated by the steam generating means, and the steam in the pot is released from the steam hole to the outside of the machine. In conjunction with this, high-temperature steam generated by the steam generating means can be put into the pan, and cooking unevenness can be suppressed.

  Also, depending on the rice species, the steam hole can be closed in each step of rice cooking, and the required high temperature and high pressure can be maintained, so the rice cooking performance is more stable.

  Also, when the steam hole is closed, the pressure in the pan becomes higher than the atmospheric pressure, and when the steam hole is open, the steam is heated into the pan so that the pressure is increased. By alternately performing the steam heating, the upper and lower heating unevenness can be eliminated, and the added steam can be heated to a high pressure so that it can be cooked softer in the rice cooking process. In addition, in the rice cooking process and the heat-retaining process, the steam that has been added penetrates further into the bottom of the pan, and it can be heated and hydrated without drying without unevenness in the top and bottom of the pan. The rice cooking performance to cook the rice or the heat insulation performance to maintain the moist insulated rice at an appropriate temperature is obtained.

  In the third invention, the water tank according to the first or second invention is provided in the steam cylinder, and the water in the water tank is heated by the steam passing through the steam cylinder. The temperature of the water supplied to can be raised in advance, the amount of heating of the lid heating means can be suppressed, the temperature unevenness of the lid heating plate can be reduced, and the water can be cooked more uniformly.

  4th invention is the reheating process which heats the heat-retained rice or the cooled rice of 1st-3rd invention, By performing the pressure heating which makes the pressure in a pan higher than atmospheric pressure by a pressure adjustment means, By heating the introduced steam to a high pressure, the steam is further permeated into the bottom of the pan. Heating and hydration can be performed in a short time without unevenness, so it can be reheated to delicious rice without drying it.

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

(Embodiment 1)
First, the overall configuration will be described.

  1 is a cross-sectional view of a rice cooker according to Embodiment 1 of the present invention. The rice cooker main body 14 has a pan 1 that accommodates an object to be cooked, such as rice or water, in a detachable manner, and a lid 4 that covers the upper surface of the rice cooker main body 14 in an openable and closable upper portion. The pan 1 is heated by a pan heating means 2 such as a heating coil provided on the bottom surface of the pan 1 and a pan side heating means 3 provided on the side surface. The pan temperature detecting means 7 is provided at the bottom of the pan 1 and detects the temperature of the pan 1. The lid 4 includes a lid cover 4a constituting the lower part of the lid 4, a lid heating plate 5 and a lid heating plate 5 that are detachably provided on the lid cover 4a and cover the opening of the pan 1 when the lid 4 is closed. A lid heating plate heating means 6 such as a heating coil for induction heating and a lid heating plate temperature detection means 8 for detecting the temperature of the lid heating plate 5 are provided.

  When the lid 4 is closed, a gap is formed between the pan 1 and the lid heating plate 5, and the gap is sealed with a loop-shaped packing 5 b attached to the lid heating plate 5. Is sealed.

  The pressure adjusting means 9 includes a steam hole 5a for releasing steam in the pot 1 provided in the lid heating plate 5, a steam hole opening / closing means 9b for moving the spherical valve body 9a to open and close the steam hole 5a, a pot And a pressure detecting means 9c for detecting the pressure in 1 and by closing the steam hole 5a and filling the pot 1 with steam, the pressure in the pot 1 is set to atmospheric pressure or more, and the steam hole 5a is opened. The pressure in the pan 1 is reduced to atmospheric pressure by discharging the steam in the pan 1 to the outside through the steam cylinder 4b that communicates the steam hole 5a and a second steam hole 12a provided in the steam hole cover 12 described later. To be equivalent. The steam cylinder 4 b is configured by a recess in which the upper surface of the lid 4 is recessed and the steam hole cover 12. The steam cylinder 4b may be configured separately from the lid 4.

  The water tank 10 is a container for storing a predetermined amount of water for generating steam necessary for cooking rice, and is configured to be detachable on the upper portion of the lid 4. The water tank 10 is connected to the water supply means 11 provided on the lid 4, and the water supply means 11 is operated to supply the water in the water tank 10 to the steam generator 5 d which is a recess provided on the lid heating plate 5.

  The water supply means 11 may be a valve body and a valve drive mechanism for dripping the water of the water tank 10 mounted on the upper part to the steam generation unit 5d. However, in the first embodiment, the predetermined amount of water is more stable. The pump is configured to supply water, and the amount of water supply can be controlled according to the operation of the pump. In addition, since such a water supply mechanism can be comprised with a general component, detailed illustration is abbreviate | omitted.

  FIG. 2 is a plan view of the lid heating plate of the rice cooker in Embodiment 1 of the present invention. The steam inlet 5c is provided in the lid heating plate 5, and the steam generated by the steam generator 5d is supplied to the pot 1 from the steam inlet 5c. The steam generated by the steam generating section 5d is not directly in contact with the lid heating plate temperature detecting means 8 or the pressure detecting means 9c by the loop-shaped packing 5e and packing 5f, and the steam inlet 5a or spherical valve body is used. It is the structure which does not contact 9a directly.

  The steam hole cover 12 covers the water tank 10 attached to the lid 4 and is openable and closable and has the second steam hole 12a for discharging steam as described above.

  The control unit 13 includes a heating unit control unit 13a and a temperature measurement unit (measurement unit) 13b, and a signal input by an input operation unit 15 provided on the front surface of the rice cooker body 14 and a storage unit (not shown). ), The rice cooking process is executed on the basis of the values of the temperature, the temperature rise rate, the time, the pressure value, the temperature, the temperature rise speed, etc. in the cooking process. In the rice cooking process, the heating means control unit 13a controls the pot heating means 2, the pot side surface heating means 3 and the lid heating means 6 based on detection signals from the pot temperature detecting means 7 and the lid heating plate temperature detecting means 8.

  FIG. 3 is a front view of input operation unit 15 of the rice cooker in Embodiment 1 of the present invention. The input operation unit 15 is operated when a user sets a desired operation course or the like or starts a rice cooking process or the like. The input operation unit 15 includes switches such as a rice cooking start switch 15a and a display unit 16. is doing. The display unit 16 is a main display unit 16a that displays the end of cooking, a selected course, and the like, a rice cooking lamp 16b indicating that the rice cooking process is being performed, a heat retaining lamp 16c that indicates that the heat retaining process is being performed, and a reheating process. A reheating lamp 16d indicating that the pressure in the pan is being increased, a pressure lamp 16e indicating that the pressure in the pot is being increased, a steam lamp 16f indicating that the steam is being injected, and the like.

  Next, each process of the rice cooking process will be described.

  The rice cooking process of the rice cooker in Embodiment 1 of this invention is comprised in order of a water immersion process, a cooking process, and a steaming process. In addition, the process which maintains the inside of a pan at high temperature is performed in a cooking process, and this is also called a boiling maintenance process.

  The water immersion process is a process for sufficiently gelatinizing the center of the rice in the subsequent processes by immersing the rice in water having a temperature lower than the gelatinization temperature and allowing the rice to absorb water in advance. Therefore, the pot heating coil as the pot heating means 2 and the pot side heating coil as the pot side heating means 3 are energized so that the temperature of the rice and water rises to a temperature at which rice gelatinization does not start. And heat the sides. The whole rice in the pan 1 is maintained uniformly at a target temperature, and the water absorption conditions of the rice in the pan 1 are kept uniform. FIG. 1 is a cross-sectional view of a rice cooker during a water immersion process in Embodiment 1 of the present invention. The predetermined temperature is maintained at 40 ° C. to 60 ° C. at which no gelatinization occurs.

  Further, at the start of the water immersion process, the water supply means 11 operates to supply a predetermined amount of water necessary for generating steam to be put into the pan in the subsequent cooking process to the steam generating unit 5d.

  If a water immersion process is performed for a predetermined time, a cooking process will be performed next. FIG. 4 is a cross-sectional view of the rice cooker during the cooking process according to Embodiment 1 of the present invention. In the cooking step, the bottom surface of the pan 1 is heated mainly by the pan heating means 2, and the temperature of rice and water in the cooked rice is raised to the boiling point of water. Of course, you may heat with the pan heating means 2, the pan side surface heating means 3, and the lid | cover heating means 6. Further, at the stage where steam is generated by boiling water in the pot 1, the steam hole 5a is closed by the steam hole opening / closing means 9b which is the pressure adjusting means 9, and the inside of the pot 1 is sealed. By maintaining the internal pressure at a pressure higher than the atmospheric pressure, the boiling point of water in the pan 1 and the steam generating unit 5d is increased and cooked in a pressurized state. The rice in the entire pan 1 is quickly heated to gelatinize the rice starch.

  Starch gelatinization starts when the temperature of rice and water in the pan 1 reaches around 60 ° C. during the cooking process. In this cooking process, if the rice is boiled rapidly in order to shorten the cooking time, the surface of the rice will be gelatinized first, and water and heat transfer to the inside of the rice will not be possible, especially gelatinization in the center of rice. Because the rice cooking process is finished in a state where the cooking is not completed, it becomes a sticky rice without stickiness. However, rice that has undergone a moderate water immersion process can be cooked with water at 100 ° C. or higher because the pressure in the pan 1 is higher than atmospheric pressure, and it is boiled rapidly at an increased temperature rise rate. The amount of heating per unit time can be increased as compared with the case of cooking with, and gelatinization can be promoted. When the lid heating plate temperature detecting means 8 detects that the water in the pot 1 has boiled, the process proceeds to the boiling maintaining process of the cooking process.

  In the boiling maintaining step, boiling is maintained while opening the steam hole 5a by the pressure adjusting means 9 to make the pressure in the pan 1 equal to the atmospheric pressure. FIG. 5 is a cross-sectional view of the rice cooker in the boiling maintenance step in Embodiment 1 of the present invention.

  At this time, by opening the steam hole 5a, the inside of the pan 1 is at atmospheric pressure, and the water in the steam generating unit 5d that has become equal to or higher than the boiling point of the atmospheric pressure boils, and steam is generated. This boiling is maintained by operating the lid heating means 6. This steam is heated by the lid heating plate 5 heated by the lid heating means 6 while moving from the steam generating part 5d to the steam inlet 5c, and is introduced into the pot 1 from above through the steam inlet 5c as high-temperature steam. In addition, the rice is heated uniformly in the entire upper and lower sides together with the steam generated by boiling the water in the bottom of the pot 1, so that the gelatinization is performed uniformly.

  Here, the lid heating means 6 cannot be provided in the portion of the lid heating plate 5 where the steam cylinder 4b is provided. For this reason, the portion of the lid heating plate 5 where the steam cylinder 4b is not provided is such that the portion heated by the steam from the pan 1 or the portion heated by the lid heating means 6 is heated and heated, and the pressure adjusting means 9 is A temperature difference occurs between the provided portion and the other portions, resulting in uneven heating. However, since the water in the steam generation unit 5d has risen to the boiling point of atmospheric pressure or higher, the amount of heating by the lid heating means 6 can be reduced as compared with the case of non-pressure rice cooking, and temperature unevenness can be suppressed.

  Moreover, since water convects by boiling from the bottom part, when water flows violently between rice, water and heat are supplied uniformly to the whole rice in the pan 1, and gelatinization is accelerated | stimulated. Further, when the water in the pot 1 evaporates, the steam hole 5a is opened, so that steam flows. The steam passes through the rice and rises and is discharged from the steam hole 5a to the outside of the rice cooker. Is further promoted by passing between the rice.

  When the cooked water in the pot 1 evaporates and almost disappears, the temperature of the pot 1 rises rapidly. When the pan temperature detecting means 7 detects a predetermined temperature due to this rapid rise, the boiling maintenance process is terminated, and the process proceeds to the next steaming process. That is, the time of the boiling maintenance process depends on the amount of water supplied into the pot 1 in the water immersion process. Since the moisture content of the rice subjected to the pressure treatment at the highest temperature and the highest pressure in the cooking process is high, the time required for water absorption of the rice can be shortened. Thereby, the power consumption of the heating energy which heats water in a cooking process and a boiling maintenance process can be suppressed.

  When the water in the steam generating unit 5d runs out, a predetermined amount of water for generating steam necessary for the steaming process is supplied to the steam generating unit 5d again by the operation of the water supply means 11, and heated in the boiling maintaining process. .

  Finally, in the steaming process, the pan heating means 2 heats the bottom of the pan 1 to such an extent that the rice on the bottom of the pan 1 does not dry or burn, closes the steam hole 5a, and fills the pan with the steam. By maintaining the pressure at a pressure higher than the atmospheric pressure, it is steamed in a pressurized state. High-temperature steam at 100 ° C. or higher becomes fine particles, passes through the gaps in the rice in the pot 1, reaches the bottom of the pot 1, and wraps each grain of rice.

  Furthermore, as shown in FIG. 5, the spherical valve body 9a is moved by the pressure adjusting means 9 to open the steam hole 5a, so that the inside of the pan 1 becomes atmospheric pressure.

  Furthermore, as shown in FIG. 6, the water supplied from the water tank 10 to the steam generation unit 5 d is mainly vaporized by the heating of the lid heating means 6, and further heated by the lid heating plate 5, while being steamed as high temperature steam having a boiling point or higher. It is introduced into the upper part of the pan 1 from the introduction port 5c. Hot steam is fed into the pan 1 through the steam inlet 13. There is little free water that is not absorbed by the rice in the pot 1, so there is little steam newly generated from the bottom, and high temperature steam is supplied to all the rice in the pot 1, and gelatinization occurs. Uniformly maintained.

  The high temperature steam is put into the pan 1 as indicated by the arrow P, gives heat energy to the rice, and is discharged from the steam hole 5a and the second steam hole 12a as indicated by the arrow Q. At the same time, the side surface of the pan 1 is appropriately heated by the pan side heating means 3. The lid heating means 6 causes the lid heating plate 5 to generate heat so that dew does not adhere to the lid heating plate 5. Also, the portion of the lid heating plate 5 where the steam passes and heats the lid is heated to a temperature higher than 100 ° C. and not overheated based on the temperature detected by the lid heating plate temperature detecting means 8. Heated by means 6.

  Since the pot 1 is heated by the pot heating means 2, the pot side surface heating means 3 and the lid heating plate heating means 6 while filling the inside of the pot 1 with the introduced steam, drying and scorching of the rice can be suppressed.

  Thus, in the steaming process, it is important to keep the pan 1 at the high temperature, that is, the temperature at which the rice is not dried or burned so that the rice is gelatinized to the core. For this reason, according to the first embodiment, high-temperature steam generated from the water in the water tank 10 and further heated is supplied to the upper space of the pan 1 from the steam inlet 5c.

  High-temperature steam adheres to and condenses on rice at 100 ° C. or lower, and heat is applied to the rice to increase the temperature and promote gelatinization. At the same time, condensed moisture adheres to the surface. Further, the temperature difference between the high-temperature steam and the rice is 50 to 60 ° C. or less, the flow rate of the high-temperature steam is small, and the charging time is short. Therefore, the rice is not dried to the extent that excess moisture on the surface of the rice grains is dried. That is, without drying the rice, heat energy for promoting gelatinization of the rice starch is supplied, the gelatinization of the rice is promoted, and the rice cooking performance is improved. In the cooking step and the steaming step, the temperature unevenness of the rice is small due to the action of high temperature steam, the gelatinization is uniform, the unevenness of stickiness and water absorption is small, the taste is stable, and high rice cooking performance is obtained. Of course, it is needless to say that the proper steam input amount and steam temperature change depending on the target cooked state, that is, the texture and the amount of rice cooked.

  After performing the steaming process for a predetermined time, a heat retaining process for maintaining the temperature in the pan 1 at a predetermined temperature (for example, around 70 ° C.) is performed. In the first embodiment, in the steaming step A3, water is supplied to the steam generating unit 5d by the water supply means 11, and this water is heated in the heat retaining step.

  The pressure adjusting means 9 is composed of a steam hole 5a for releasing steam in the pan 1, a steam hole opening / closing means 9b for opening / closing the steam hole 5a, and a pressure detecting means 9c, so that the amount of cooked rice and the amount of water can be adjusted. By detecting the pressure change in the pan 1 due to the amount of steam generated in the pan 1, etc., and releasing the steam, it is controlled to a predetermined pressure and temperature in each step of cooking rice, Since the pressure drop can be confirmed and steam can be introduced, the rice cooking performance is stabilized by maintaining the pressure at a predetermined high temperature and high pressure.

  In addition, according to rice seed | species, the steam hole 5a can be closed at each process of rice cooking, and it can also be hold | maintained in the required high temperature / high pressure state, Therefore Rice cooking performance becomes more stable.

  In addition, in order to detect the pressure in the pan 1, it may replace with the pressure detection means 9c, and the temperature detection means which can measure the temperature in the pan 1 may be sufficient.

  In addition, in the heat retaining step, steam is generated from the water of the steam generating unit 5d at a predetermined time interval and introduced into the pan 1, thereby suppressing the drying of the rice and driving out the heat retaining odor in the pan 1. It maintains the taste.

  Further, the effects of “pressure heating” and “steam heating” will be described.

  FIG. 7: is a time chart which shows the operation | movement of the temperature change in a pan, pressure change, steam injection | pouring, and a water supply means in each process of the rice cooker in Embodiment 1 of this invention.

  In the submergence process started at time t0, a small amount of water for generating steam is supplied in advance to the steam generating unit 5d by the operation of the water supply means 11. At the time t1, the cooking process is started and the boiling of the water in the pan 1 is started. Since the steam hole 5a is closed by the pressure adjusting means 9, the pot 1 is filled with steam at the time t2, and the pressure in the pot 1 becomes atmospheric pressure or higher.

  After a predetermined time from the time t2, the steam hole 5a is opened by the pressure adjusting means 9, and the steam is discharged so that the pressure in the pan 1 becomes atmospheric pressure. Thereafter, the steam generated by heating by the lid heating means 6 is heated by the lid heating plate 5 and put into the pan 1. Subsequently, a small amount of water for generating steam is supplied to the steam generating unit 5d by the water supply means 11 at time t2 '.

  In the latter half of the cooking process A2, the “boiling maintenance process” is performed such that the temperature in the pot 1 is maintained at atmospheric pressure and the water in the pot 1 is boiled. In this step, the steam hole 5a is opened by the pressure adjusting means 9 to release steam to the outside of the machine, and by maintaining boiling, water and heat are supplied to the rice to promote gelatinization. At the final stage of this boiling maintenance process, water is running out, and the steam adjusting hole 9 is closed by the pressure adjusting means 9, so that the steam is filled in the pan 1, and the pressure in the pan 1 becomes atmospheric pressure or higher.

  At time t3, when the pan temperature detecting means 7 detects that the water in the pan 1 has run out and the temperature of the pan 1 has rapidly increased to reach a predetermined temperature, the steaming process is started. Since the steam hole 5a is closed by the pressure adjusting means 9, the pressure in the pan 1 is higher than the atmospheric pressure, the steam fills the pan 1, and the gelatinization of rice is further increased.

  After a predetermined time from time t3, the steam hole 5a is opened by the pressure adjusting means 9 at time t3 ', and the steam is discharged so that the pressure in the pan 1 becomes atmospheric pressure. Next, the steam generated by heating by the lid heating means 6 is heated by the lid heating plate 5 and put into the pan 1. The sweetness and aroma of rice increase by perfecting gelatinization by heating and hydration acting on rice by condensing steam at a high temperature above the boiling temperature.

  At time t4, the rice cooking process is terminated and the process proceeds to a heat retaining process. Note that a small amount of water for steam generation is supplied to the steam generation unit 5d by the water supply means 11 at time t3 ″ for the next heat retaining step.

  As described above, by performing pressure heating and steam heating, it is possible to cook rice that has been sufficiently gelatinized without unevenness in the upper and lower sides.

  In addition, in order to heat the water supplied in the steam generation part 5d with the lid | heater heating means 6 and produce | generate a steam, the new heating means which produces | generates a steam and supplies it in the pan 1 is unnecessary, and is the structure of the conventional rice cooker Of course, other steam generating means that generates steam and supplies it into the pan 1 may be used. By using another independent steam generating means, steam can be intermittently charged.

  In addition, the rice operation input part (not shown) which selects the rice seed | species which cooks rice is provided in the input operation part 13, and the pressure value appropriate for each rice seed | species is memorize | stored in a memory | storage means, respectively, By adjusting with the pressure adjustment means 9 so that it may become a corresponding pressure value, it can be cooked with temperature and pressure suitable for each rice kind. For example, in the case of brown rice, it can be cooked without hardness and crispness by making the pressure value higher than when white rice is selected. Moreover, by making it possible to select rice varieties more finely from soft rice and hard rice, new rice and old rice, white rice and brown rice, etc., more appropriate rice cooking can be performed for each rice variety.

  In addition, although the pan heating means 2, the pan side heating means 3 and the lid heating plate heating means 6 use induction heating, any heat source such as an electric heater or gas combustion may be used. It does not have to be. Moreover, each may be a single ring shape, and may be divided | segmented into plurality. Of course, it may be composed of a plurality of coils.

  The pan temperature detecting means 7 and the lid heating plate temperature detecting means 8 may be any detection principle as long as it can detect a range from a temperature during normal operation to a high temperature at the time of abnormality.

  In addition, although the pressure control means 9 adjusted the pressure in the pan 1 by opening and closing the steam hole 5a of the lid | cover heating plate 5, as long as the pressure in the pan 1 can be controlled, what kind of thing may be used.

  In the rice cooking process or the heat-retaining process, “pressure heating” in which the pressure in the pan 1 is set higher than atmospheric pressure and “steam heating” in which steam is introduced into the pan 1 are alternately repeated, thereby causing uneven heating in the upper and lower sides. In addition, the steam that has been added is heated to a high pressure so that it can be cooked softer in the rice cooking process. Moreover, in the rice cooking process and the heat-retaining process, the introduced steam is further infiltrated into the bottom of the pan 1, and heating and hydration can be promoted without drying, without unevenness in the top and bottom of the pan 1, thereby promoting gelatinization. The rice-cooking performance for cooking delicious and delicious rice and the heat-retaining performance maintained in moist heat-retaining rice at an appropriate temperature are obtained.

  In addition, in the reheating process for heating the heat-insulated rice or the cooled rice, at least the “pressure heating” in which the pressure in the pan 1 is made higher than the atmospheric pressure is performed, so that the steam generating part 5d generates the steam inlet 5c. The steam introduced from is heated to a high pressure so that the steam further penetrates into the bottom of the pan 1. Since heating and hydration can be performed in a short time without unevenness, the rice can be reheated to delicious rice without drying.

  It should be noted that the steam heating means for further heating the steam supplied by the steam generating means formed by the water tank 10, the water supply means 11, the steam generating unit 5d, the lid heating means 6 and the like into the pan 1 is the lid heating plate 5, the lid By providing it with the heating means 6 etc., the temperature of a vapor | steam can be made into the high temperature steam of the temperature exceeding the boiling point of water, and can be thrown in in the pan 1. While the temperature in the pan 1 is 100 ° C. or higher in the conventional cooking process of pressure rice, steam of a high temperature equal to or higher than that is injected, and the temperature of the rice is not lowered even in the steaming process. High temperature can be maintained.

  In addition, by controlling the operation of the lid heating means 6 according to the type and state of rice, such as white rice and brown rice, new rice and old rice, it is possible to inject high-temperature steam at the required temperature, and by sufficient gelatinization Boiled rice with good taste with sweetness and stickiness improves cooking performance. That is, the same effect can be achieved by introducing steam heating in the heat-retaining step after the rice cooking step or in the reheating step for the user to heat the rice as needed for the cooled rice. it can.

  As shown in FIG. 2, since the water tank 10 that stores water for generating steam and the steam hole cover 12 are separate, the water tank 10 that stores the water by opening the steam hole cover 12. However, these may be integrated. Furthermore, when the lid 4 is opened and closed, the water in the water tank 10 is held inside and does not scatter around. Furthermore, the water tank 10 can be detached even when the lid 4 is opened.

  The steam hole opening / closing means 9b for moving the spherical valve body 9a of the pressure adjusting means 9 can be formed of an electric motor, a solenoid, a shape memory alloy that expands and contracts according to temperature, etc. It is also a well-known technique, and illustration is omitted.

  The lid heating plate 5 is made of a metal material. However, the lid heating plate 5 may be a multilayer metal plate or may be partially thick. In particular, the heat capacity of the steam passage portion such as the steam heating portion 14 is increased. If it is the structure to enlarge, the heating effect of a vapor | steam will improve and it will not be limited to this.

  Further, the rice cooker configured as described above will be supplementarily explained in terms of how to use the device, control of the pressure in the pan 1, and generation of steam.

  Rice for cooking rice and water corresponding to the amount of rice are put in a pan 1 and stored in the rice cooker 1. In addition, a predetermined amount of water is supplied to the water tank 10. Furthermore, if a user operates the rice cooking switch 15a of the input operation part 15, the control means 13 will receive the input from a rice cooking switch, and will perform a rice cooking process.

  In the rice cooking process, the pan temperature detecting means 7 detects the temperature of the bottom surface of the pot 1 and sends a signal to the control means 13. Based on the signal from the pan temperature detection means 7, the control means 13 sets the water and rice conditions in the pot 1 as appropriate values in each of the rice cooking steps roughly divided into the soaking, cooking and steaming steps. The energization amount to each heating coil of the pan heating means 2, the pan side heating means 3, and the lid heating means 6 is controlled so as to be maintained at a predetermined temperature or a predetermined time.

  That is, the pan heating means 2 and the pan side surface heating means 6 generate heat at the bottom and side surfaces of the pot 1 by induction heating with the current supplied from the control means 13. Similarly, the lid heating unit 6 also causes the lid heating plate 5 to generate heat by induction heating with a current supplied from the control unit 13. Moreover, in each process of water immersion, cooking, and steaming, the temperature control of the rice during cooking is performed as shown in FIG. 8 by switching the open / close state of the spherical valve body 9a.

  Moreover, when the spherical valve body 9a is in a closed state in the cooking process, the pressure in the pan 1 is higher than the atmospheric pressure, and the water in the water tank 10 as well as the rice and water in the pan 1 Is also maintained at high temperature and pressure. When the pressure in the pan 1 rises above a predetermined pressure and passes a predetermined time, the spherical valve body 9a is switched to the open state, the pressure in the pan 1 is reduced to atmospheric pressure, and the boiling point of water is lowered. The water in the pot 1 as well as the water in the water tank 10 boils a little, and steam is generated. The steam generating unit 5d is heated by the lid heating means 6, and the generated steam is gradually heated while moving on the surface of the lid heating plate 5, and is introduced into the pan 1 as high-temperature steam from the steam inlet 5c. The Therefore, by controlling the operation of the spherical valve element 9a, the opening / closing time and the number of opening / closing operations by the control means 13, high-temperature steam can be introduced into the pan 1 in the cooking and steaming process.

  In addition, since the steam generation part 5d receives heat radiation from the pan 1 and the heated rice in the cooking process by arranging it on the lid 4, when steam is generated from the steam generation part 5d in the subsequent process, steam generation is performed. The water in the portion 5d is preheated to a high temperature in advance. That is, in the cooking process and the steaming process, if the on-off valve is opened, the boiling point of water is lowered and water immediately boils, so that steam can be generated in a short time and high-temperature steam can be obtained. Since the heat energy required for cooking rice can be input at a predetermined timing, the responsiveness is good, and this also saves energy.

  The water tank 10 is composed of a heat-resistant container such as a metal material or a composite material, and the heating is shared by the lid heating means 6 or a heating coil or heater for induction heating is provided as a dedicated heating means. It is good also as a structure. It goes without saying that the water tank 10 and the lid heating plate 5 can be heated by the lid heating means 6.

  A means for heating the water tank 10 may be provided exclusively. In this way, the water tank 10 can be heated to a high temperature or a low temperature different from the heating temperature of the lid heating plate 5 by the lid heating means 6, and the rice is cooked and the heat retention is controlled more precisely. The texture can be controlled.

  In addition, although the water tank 10 is formed separately from the lid heating plate 5, these may be formed integrally. As a result, the water tank 10 can be heated by the lid heating means 6, the timing of steam generation can be controlled relatively freely, the rice is cooked, the heat retention is controlled more precisely, and the texture of the rice is improved. Can be controlled.

  The water tank 10 is removed every time rice is cooked to store a predetermined amount of water, but other water supply means may be provided. For example, a water supply mechanism may be used in which a large second water tank is accommodated in the main body or the lid 4 so that a necessary amount of water is directly input to the water tank 10 or the steam generation unit 5d at a predetermined timing. It is. Thus, normally, it is only necessary to replenish the second water tank with water, so that the trouble of supplying water to the water tank 10 each time rice is cooked can be saved and the usability is improved.

  In the first embodiment, the lid heating plate 5 generates heat to heat the steam. However, in the space communicating from the steam generating unit 5d to the steam inlet 5c, other heat sources in addition to the lid heating plate 5 are used. The structure which makes it high temperature steam by arrange | positioning may be sufficient. Of course, the fact that such a dedicated heat source is not required improves the rice cooking performance while maintaining the installation and operability without increasing the size of the device.

  The steam heating means for heating the steam generated by the steam generating means may be at least one of the lid heating plate 5 and the lid heating means 6, without adding a dedicated heat source for this purpose, The rice cooking performance is improved by generating high-temperature steam without increasing the size of the rice and supplying the necessary amount of further high-temperature energy to the rice heated to high temperature at high pressure at an appropriate timing.

  Note that the steam to be introduced is not limited to a temperature exceeding 100 ° C. at the steam inlet 5 c to be introduced into the pan 1. Of course, if it is high-temperature steam immediately before the addition, the rice cooking performance will be dramatically improved. However, after it is introduced into the pan 1, it is made into high-temperature steam with the heat energy from the side of the lid heating plate 5 or the pan 1 and supplied to the rice. The same effect can be obtained.

  The lid heating means 6 is a lid heating plate heating coil for induction heating the lid heating plate 5, and the lid side surface heating means 3 is a pan side heating coil for induction heating the side surface of the pot 1. It is not limited to induction heating. What is necessary is just a means which can supply the calorie | heat amount required by a rice cooking process with respect to each site | part. Needless to say, in addition to the conventionally known heaters, hot air, high temperature steam, gas combustion, and the like may be combined.

  The lid heating plate 5 is formed of a single layer or a multilayer metal material, but a heat storage unit is provided on a part or all of the lid heating plate 5 including the steam generating unit 5d and the portion where the steam is heated. It may be a thing. In this way, if water is dripped in a state where high temperature energy is held in the heat storage section, steam can be generated in a short time, and steam is put into the pan 1 at a necessary timing in the rice cooking process or the heat retaining process. can do.

  In addition, the pan side surface heating means 3 can heat the upper space of the pan 1 from a side surface according to the amount of cooked rice by being multistage in the vertical direction. Of course, a single heating coil may be used.

  The pressure adjusting means 9 controls the steam pressure and the steam temperature in the pan 1 by the steam generated in the pan 1 in the steaming step, not limited to the cooking step of cooking rice. Can be cooked. That is, if the time and number of times the spherical valve body 9a is operated are controlled, the heating conditions of the steam generated by the steam generating means, the amount of steam supplied to the pan 1 and the discharge amount can be controlled, and the heating conditions for the rice Various tastes are realized by controlling the rice cooking performance.

  In addition, although the high temperature steam is thrown in the latter half part of cooking and the steaming process, depending on the operation method of the pan heating means 2, the pan side heating means 3, and the lid heating means 6, the kind of rice, the degree of deterioration, the rice to be cooked The rice cooking performance is improved even if it is added only in a part of the process due to the difference in the preference regarding the hardness of the rice. Also, assuming this, the amount of water used for generating steam is reduced, the size of the water tank 10 can be reduced, and the inner volume of the pan 1 is hardly affected. It will also be compact.

  The lid heating means 6 and the steam heating means can be operated in the cooking process, and the steam and water tank 10 can be brought to a high temperature.

  In addition, as is done conventionally, according to the type of rice, the pressure and temperature conditions of the cooking process are set and selected, realizing rice cooking suitable for each, rice stickiness, hardness, etc. Can be controlled, and variations in taste can be suppressed to improve taste.

  In addition, the input operation unit 15 is provided with a rice seed input unit (not shown) for selecting rice varieties (white rice, brown rice, non-washed rice), freshness (new rice, ordinary rice, old rice), etc. The storage means stores the appropriate temperature increase rate for each rice variety and freshness, and the core remains by executing the cooking process at a temperature increase rate according to the selected rice variety and freshness. Can be cooked to the right hardness.

  As described above, the rice cooker according to the present invention improves rice cooking performance by promoting gelatinization without unevenness without drying the upper and lower rice in the pan while maintaining equipment installation and usability. Therefore, it can be applied to the use of a commercial rice cooker that requires space saving and simple operation. Moreover, it can apply also to uses, such as a commercial rice cooker and a cooker corresponding to various rice cooking menus and cooking menus, by using together heating by high temperature / high pressure and steam heating.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. Top view of the lid heating plate of the rice cooker Front view of the input operation unit of the rice cooker Sectional view in the cooking process of the rice cooker Sectional view in the boiling maintenance process of the rice cooker Sectional view in the steaming process of the rice cooker Time chart showing the temperature change, pressure change, steam input and operation of water supply means in each process of the rice cooker Sectional drawing which shows the conventional rice cooker body

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pan 2 Pan heating means 3 Pan side surface heating means 4 Lid 4b Steam cylinder 5 Lid heating plate 5a Steam hole 5c Steam inlet 5d Steam generation part 6 Lid heating means 7 Pan temperature detection means 8 Lid heating plate temperature detection means 9 Pressure adjustment Means 9a Spherical valve body 9b Steam hole opening / closing means 9c Pressure detection means 10 Water tank 11 Water supply means 12 Steam hole cover 12a Second steam hole 13 Control means 14 Rice cooker body 15 Input operation unit

Claims (4)

A pan, a pan heating means for heating the pan, a lid covering the opening of the pan, a lid heating plate provided on the lid, a lid heating means for heating the lid heating plate, and the lid heating plate A steam hole for discharging steam in the pan, provided in the lid, a steam cylinder for discharging steam from the steam hole to the outside of the machine, a pressure adjusting means for adjusting the pressure in the pan, and A water tank mounted on the lid, a steam generator provided in the lid heating plate for storing water supplied from the water tank, and steam generated by the steam generator provided in the lid heating plate in the pan A rice cooker equipped with a steam inlet to be put inside. 2. The rice cooker according to claim 1, wherein the pressure adjusting means includes steam holes, steam hole opening / closing means for opening and closing the steam holes, and pressure detecting means for detecting the pressure in the pan. The rice cooker according to claim 1 or 2, wherein the water tank is provided in a steam cylinder. The pressure heating which makes the pressure in a pan higher than atmospheric pressure by a pressure adjustment means is performed in the reheating process which heats heat-retaining rice or cold rice, The any one of Claims 1-3 characterized by the above-mentioned. Rice cooker.