JP5145962B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker that cooks and retains heat using superheated steam.

  Since ancient times, "how to cook delicious rice" has been handed down based on cooked rice. The “delicious rice” that has been realized in cooking rice cakes is generally considered to be cooked rice with a strong stickiness and flavor. Typical elements for realizing them are (1) high thermal power by firewood and (2) heat insulation by firewood. In recent rice cookers, (1) has achieved a high thermal power with the development of IH technology, and (2) has achieved a structure close to rice-cooking by improving heat insulation by diversifying the inner pot material. However, with this configuration alone, it is difficult to say that the stickiness and flavor that are characteristic of rice cooked with salmon are sufficiently extracted.

It is common for rice cooked with rice cake to be burnt at the bottom, which is the contact portion with the feather pot. This scorching occurs when the moisture of the rice is exhausted, that is, in the steaming process, which is the final process of cooking rice, by cooking the lower layer of the rice with a high heating power using rice cake. In this steaming process, by cooking with high heat, the moisture generated from the lower layer of rice inside the pot reaches the upper layer, and heat is passed through each grain of rice inside the pot to the core. We realize sticky rice cooked rice. At this time, the pressure inside the hood is 40 to 50 mmH ₂ O (0.004 to 0.005 atm), and the movement of high-temperature moisture (water vapor) inside the rice cake under this pressure is characteristic of rice cooked with rice cake. It is one factor that brings out the stickiness and flavor.

  Patent Document 1 discloses a rice cooker that supplies superheated steam to rice during the steaming process. In the unevenness process, the water put in the inner pot at the start of rice cooking is absorbed into the rice and evaporated to almost disappear. However, a lot of moisture tends to remain at the bottom of the inner pot. In order to remove the excess water and promote gelatinization of the rice, the inner pot is also heated in the steaming process. However, since there is little moisture, when heated from the bottom of the inner pot, the rice near the surface to be heated will burn. In addition, the rice on the upper surface of the inner pot is easily dried because moisture is actively evaporated. In order to avoid these phenomena, the rice cooker of Patent Document 1 is heated by steam from the top surface even in the steaming process, so that the charred and top surface of the rice due to the local temperature rise of the entire inner pot and the top surface thereof Prevents the drying of nearby rice.

  A cross-sectional view of the rice cooker of Patent Literature 1 is shown in FIG. An inner pan 101 is detachably mounted in the main body 100, and an openable / closable lid 102 that covers the upper surface of the inner pan is provided. Further, in order to heat the rice and water in the inner pot 101, the inner pot heating means 103 is disposed at the bottom of the inner pot 101, and the lid heating means 104 is disposed in the lid body 102. Further, in order to control the heating state of the cooked rice, an inner pot temperature detecting means 105 for detecting the temperature of the inner pot 101 and a lid temperature detecting means 106 for detecting the temperature of the upper surface of the inner pot 101 are arranged at the bottom of the inner pot 101. The control means 107 operates the inner pot heating means 103 and the lid heating means 104 in a timely manner based on the detected temperatures of the inner pot temperature detecting means 105 and the lid temperature detecting means 106.

  A water tank 108 is installed in the main body. The water tank 108 has a water tank heating means 109, and the water tank 108 and the water tank heating means 109 constitute a steam generation means 110. Further, the steam generation means 110 and a part of the upper surface of the inner pot 101 are connected by the steam pipe 111, and the opening on the upper surface of the inner pot 101 is a steam hole 112. An on-off valve 114 is installed above the steam outlet 113 from which steam is discharged from the inner pot 101 to the outside of the main body 100. Further, the main body 100 has an inner pot heating means 103, a water tank heating means 109, and an on-off valve control means 115 for controlling the on-off valve 114 based on the output of the inner pot temperature detecting means 105.

The operation of the above configuration will be described. Cook the rice and water corresponding to the amount of rice 1
01 is put in the main body 100 in a predetermined state. Furthermore, when a predetermined amount of water is put into a water tank 108 provided in the main body 100 and the cooker operates a rice cooking start switch (not shown), a rice cooking process is performed. The rice cooking process is largely divided into each process of soaking, cooking, and steaming.

  In each process, the temperature and the state of the water and rice in the inner pot 101 are set as appropriate values and maintained for a predetermined time. Therefore, the inner pot heating means 103 and the water tank heating means 109 are driven while detecting the output of the inner pot temperature detecting means 105. When the water tank heating means 109 is driven, water in the water tank 108 is heated to generate steam. The steam moves through the steam pipe 111 and is discharged from a part of the upper surface of the inner pot 101 into the inner pot 101. Water and rice in the inner pot 101 are heated from the bottom of the inner pot 101 by the inner pot heating means 103, and further, the upper surface is heated by steam released to the inner pot 101. When the rice cooking process ends, the process automatically shifts to the heat retaining process.

Patent Document 2 discloses a rice cooker that supplies superheated steam to rice during the heat-retaining step. In this rice cooker, when combined with heating from the bottom of the rice with a pot by bringing steam into contact with the rice from the top, the temperature of the rice is more even than when the rice is heated only by heating the rice in the pot. Can be maintained. Therefore, it can reduce that the temperature of rice rises partly too much and becomes hard, or it can be dried, and the deliciousness of heat-retaining rice can be maintained. Furthermore, the dew condensation that occurs with the introduction of steam can be reduced, and the battering and whitening of rice can be reduced.
Japanese Patent No. 3858671 JP 2007-29142 A

However, in the rice cooker of patent document 1, since the fine pressure similar to the rice cooking in the cooking process and the steaming process was not applied, it did not reach the same taste as the rice cooking. The fine pressure in cooking rice is a very small value with respect to 40-50 mmH ₂ O (0.004 to 0.005 atm) and atmospheric pressure (1 atm). Moisture generated from the lower layer of rice inside the pot when the cook who adds high heat is linked to the steam that passes through the upper layer of rice and escapes from the slight gap between the rice cake and the lid, which is realized mechanically. There are very subtle adjustments. Although the rice cooker of patent document 1 has the on-off valve 114 and the on-off valve control means 115 which controls the on-off valve 114 above the steam discharge port 113, it is the above-mentioned short time (it may be 1 second or less in some cases). The pressure adjustment in a short time was not possible considering the linkage with the exhaust steam performed in step (1).

  Even during warming, the rice cooker of Patent Document 2 has a steam outlet that communicates with the inside of the inner pot and the outside of the rice cooker body, so a portion of the steam that has been introduced into the inner pot by the steam generating means. Had come out directly through the steam outlet before contacting the rice in the inner pot. Furthermore, when the use environment of the rice cooker is at a low temperature such as 0 ° C., outside air enters the inner pot through the steam outlet, and the temperature of the upper space in the inner pot is cooled, When steam is added, before heating the rice with steam, heat is required to heat the space. When the steam to be added is superheated steam, the temperature of the steam supplied to the rice is lowered, and When the steam is near 100 ° C., the amount of steam supplied to the rice is reduced (the steam is cooled and condensed to reduce the amount of steam). Also, since there is a large temperature difference between the steam temperature (over 100 ° C for overheated steam) and the atmosphere of the outside air, water droplets due to condensation are generated near the steam discharge port, and the water droplets enter through the steam discharge port. There was a problem that it dropped on the rice in the pan and caused a decrease in heat retention performance. In addition, in order to avoid the above-mentioned state, if the means of heating the vicinity of the steam outlet by the lid heating means and evaporating the water droplets, the problem of drying and yellowing of the upper layer of the rice due to excessive heating is caused. Furthermore, there has been a problem of an increase in power consumption.

  The present invention solves the above-described conventional problems, and at the time of the steaming process and heat retention, efficiently adds superheated steam to the rice under the slight pressure of rice cooking, and has the stickiness and flavor of rice cooking It aims at providing the rice cooker which can realize rice.

In order to solve the conventional problems, a rice cooker body, an inner pot detachably stored in the rice cooker body, a heating means for heating the food in the inner pot, and an opening of the inner pot A lid that covers the inside of the lid, a steam outlet that discharges the steam in the inner pot to the outside, a steam cylinder provided in the steam outlet, a steam generating means, and the steam generating means Steam heating means for heating the steam generated from the steam to overheated steam exceeding 100 ° C., the steam cylinder closes the steam discharge cylinder protruding from the bottom of the steam cylinder, and the upper portion of the steam discharge cylinder, A swingable steam valve having an umbrella portion whose outer peripheral portion is located outside the steam discharge tube and whose lower end surface is lower than a contact portion with the steam discharge tube, and provided in the umbrella portion and a convex outer circumferential ribs on the lower side that is, you the steaming step and incubating process When the superheated steam is thrown into the inner pan from above the inner pan, and the pressure in the inner pan when the steam valve is raised by the superheated steam reaches that pressure even in the slight pressure in the simmering The steam valve is automatically lifted together with the steam discharged from the steam outlet, and by discharging the superheated steam, the steam that goes out of the rice cooker body is minimized, effectively and efficiently Steam can permeate, can achieve the sticky and flavored rice cooked with rice cake, can suppress the starch aging of the warm rice, and can improve the taste of rice.

  The rice cooker of the present invention can efficiently add superheated steam to the rice under the fine pressure of rice cooking during the steaming step and the heat-holding step, and can realize rice with a sticky rice flavor and flavor. .

1st invention is a lid body which covers the opening part of the rice cooker main body, the inner pot detachably accommodated in the said rice cooker main body, the heating means which heats the foodstuff in the said inner pot, and the said inner pot A steam outlet provided in the lid body for discharging the steam in the inner pot to the outside, a steam cylinder provided in the steam outlet, steam generating means, and steam generated from the steam generating means Steam heating means for heating the steam to overheated steam exceeding 100 ° C., and the steam cylinder closes the steam discharge cylinder protruding from the bottom of the steam cylinder and the steam discharge cylinder, and the outer peripheral portion thereof A swingable steam valve having an umbrella portion located outside the steam discharge tube and having a lower end surface positioned lower than a contact portion with the steam discharge tube, and a lower side provided in the umbrella portion and a convex outer circumferential ribs, in steaming step and incubating process, the superheated steam The steam valve is inserted into the inner pan from above the inner pan. It is lifted in conjunction with the steam discharged from the steam outlet, and by discharging superheated steam, it is possible to minimize the steam that flows out of the rice cooker body and to penetrate the steam efficiently and effectively. It is possible to realize rice with the stickiness and flavor of cooking rice. In particular, in the heat retaining step, aging of the starch of the rice can be suppressed, and the taste of the heat retaining rice can be improved.

  The second invention is such that the steam valve is adjustable in weight, the pressure applied during the steaming process and the heat retaining process can be changed, and the stickiness and flavor of rice which is a favorite of the cooker is realized. Will be able to. In particular, in the heat-retaining process, the pressure applied at the time of steam input during heat retention can be changed, and by adding pressure, the penetration efficiency of the input steam into the rice is improved, thereby suppressing the starch aging of the rice. become able to.

  The third aspect of the invention is such that the opening area of the steam discharge tube can be adjusted, the pressure applied during the steaming process and the heat retaining process can be changed, and the stickiness and flavor of rice that the cook likes Can be realized. In particular, in the heat retaining step, it is possible to suppress the starch aging of the rice by improving the penetration efficiency of the input steam into the rice.

  In the fourth aspect of the invention, the steam valve is detachable, the replacement with a steam valve having a different weight can be facilitated, and the pressure applied during the steaming process and the heat retaining process can be changed. In addition, the care of the steam valve is improved, and the rice cooker can be used hygienically.

  The fifth aspect of the invention is such that the contact portion of the steam valve with the steam discharge tube has a spherical shape, the operation of the steam valve can be smoothed, and the pressure change in the inner pot can be linked. It is easy to keep and to move the steam valve up and down in a very short period of time. Further, since the steam valve can be prevented from being caught by the steam discharge cylinder, it is possible to prevent the superheated steam in the inner pot from being released to the outside more than necessary. Therefore, it becomes possible to come close to the atmosphere state in the cocoon cooking bowl.

  In the sixth aspect of the present invention, the steam discharge tube has at least one notch, and the steam in the inner pot is exposed to the outside even when the pressure in the inner pot reaches the fine pressure in the simmering. Realizing the release, it is possible to prevent a sudden pressure increase in the process until the target pressure in the inner pot is reached. Therefore, it becomes possible to come close to the atmosphere state in the cocoon cooking bowl. Moreover, when the steam valve is fixed, steam can be discharged from the notch, and a rapid pressure rise in the inner pot can be prevented in each rice cooking process, and a safe rice cooker can be used. .

  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)
1 is a cross-sectional view of a rice cooker according to Embodiment 1 of the present invention.

  Fig.2 (a) and FIG.2 (b) are steam valve vicinity principal part sectional drawings which showed the steam valve operation | movement in the cooking process of the rice cooker.

FIG. 3 is a cross-sectional view of the main part in the vicinity of the steam valve of the rice cooker. FIG. 4 is a correlation diagram between fine pressure and taste, the horizontal axis indicates the pressure value (unit: mmH ₂ O), and the vertical axis indicates the taste.

  Fig.5 (a) and FIG.5 (b) are steam valve vicinity principal part sectional drawings which showed the steam valve operation | movement at the time of the superheated steam injection | pouring of the steaming process and heat retention process of the rice cooker.

  1 to 3 and 5, the rice cooker body 1 according to Embodiment 1 of the present invention includes an inner pot 2 that is detachably mounted in the body, and an openable / closable lid 3 that covers the upper surface of the inner pot. . Moreover, in order to heat the rice and water in the inner pot 2, the inner pot heating means 4 is disposed at the bottom of the inner pot 2, and the lid heating means 5 is disposed on the lid 3. Further, in order to control the heating state of the cooked rice, an inner pot temperature detecting means 6 for detecting the temperature of the inner pot 2 and a lid temperature detecting means 7 for detecting the temperature of the upper surface of the inner pot 2 are arranged at the bottom of the inner pot 2. A water tank 8 is installed in the main body. The water tank 8 has a water tank heating means 9, and the water tank 8 and the water tank heating means 9 constitute a steam generating means 10. Further, the steam generation means 10 and a part of the upper surface of the inner pot 2 are connected by the steam pipe 11, and the opening on the upper surface of the inner pot 2 is defined as a steam hole 12.

A steam cylinder 14 is detachably disposed above the steam outlet 13 from which steam is discharged from the inner pot 2 to the outside of the main body 1. The steam cylinder 14 includes a steam discharge cylinder 15 provided so as to protrude upward from the bottom thereof, and a steam valve 17 having an umbrella portion 16 positioned outside the steam discharge cylinder 15 above the steam discharge cylinder 15. It is installed in a state in which the opening of the steam discharge cylinder 15 is closed. The lower end surface of the umbrella portion 16 of the steam valve 17 is provided at a position lower than the contact portion between the steam discharge cylinder 15 and the steam valve 17. A reflux port 18 is provided in the vicinity of the steam discharge cylinder 15, and a silicon rubber reflux valve 19 for sealing the reflux port 18 is provided below the reflux port 18. The bottom surface of the steam cylinder 14 is provided with an inclined surface or a groove or the like with the reflux port 18 at the lowest point, so that it is easy to guide the tap and water accumulated in the steam cylinder 14 to the reflux port 18.

  The control means 20 operates the inner pot heating means 4, the lid heating means 5 and the water tank heating means 9 in a timely manner based on the detected temperatures of the inner pot temperature detecting means 6 and the lid temperature detecting means 7.

  The operation of the above configuration will be described. The rice to be cooked and the water corresponding to the amount of the rice are put in the inner pot 2 and the interior of the main body 1 is arranged in a predetermined state. Further, when a predetermined amount of water is put into a water tank 8 provided in the main body 1 and a cook operates a rice cooking start switch (not shown), a rice cooking process is performed. The rice cooking process is largely divided into each process of soaking, cooking, and steaming. In each process, the temperature and the state of the water and rice in the inner pot 2 are set as appropriate values and maintained for a predetermined time. Therefore, the inner pot heating means 4 and the water tank heating means 9 are driven while detecting the output of the inner pot temperature detecting means 6. When the water tank heating means 9 is driven, the water in the water tank 8 is heated to generate steam. The generated steam is further heated by the steam heating means 21 and becomes superheated steam exceeding 100 ° C. at normal pressure. The superheated steam moves in the steam pipe 11 and enters the inner pot 2 from a part of the upper surface of the inner pot 2. Released. Water and rice in the inner pot 2 are heated from the bottom of the inner pot 2 by the inner pot heating means 4, and further heated by superheated steam released to the inner pot 2. Since the above-mentioned superheated steam has higher thermal energy than normal steam, heating in the inner pot 2 can be performed uniformly and for a short time. Further, by further increasing the temperature of the superheated steam by the superheated steam control means 22, it is possible to raise the temperature in the inner pot 2 in a shorter time.

  In the cooking process, while the boiling state is maintained, a phenomenon in which the liquid from which the starch has eluted from rice is released from the inner pot 2 in a state of volume expansion including bubbles will appear, so-called spillage. And

  In the unevenness process, the water put in the inner pot 2 at the start of rice cooking is absorbed into the rice and evaporated to almost disappear. However, a lot of moisture tends to remain at the bottom of the inner pot 2. In order to remove the excess water and promote gelatinization of the rice, the inner pot 2 is heated by the inner pot heating means 4 also in the steaming step. However, since there is little moisture, if it heats from the bottom of the inner pot 2, the rice near the surface heated of the inner pot 2 will be burnt. In addition, the rice on the upper surface of the inner pot 2 is easily dried because moisture is actively evaporated. In order to avoid these phenomena, the rice cooker of the present invention performs heating with superheated steam from the top surface even in the steaming step. By performing heating from the upper surface with such superheated steam, the scorching of the rice and the drying of the upper surface and the vicinity of the rice due to the local temperature rise of the entire inner pot 2 are prevented.

  Further, the superheated steam control means 22 controls the superheated steam to a temperature at which the rice is not dried, so that the rice can be heated in a short time without drying and further scorching.

When cooked rice is finished, it automatically shifts to the heat insulation process. The control means 20 is provided with the 1st heat retention course which maintains rice at about 60 degreeC, and when the temperature detected by the inner pot temperature detection means 6 is checked regularly and the rice temperature falls below about 60 degreeC. Only the inner pot heating means 4 is operated to maintain the rice temperature. When the temperature of the rice is around 60 ° C. in the first heat insulation course, the temperature of the inner pot 2 is also about the rice temperature ± 5 ° C. This first heat insulation course has an intermittent heating process in the middle, and the control means 20 operates the inner pot heating means 4 to heat the inner pot 2 periodically (about every several hours). By operating the steam generation means 10 to generate steam, the rice is heated up to about 75 ° C. By setting the temperature of the rice stored at about 60 ° C. to 75 ° C. or higher, there is an effect of suppressing the propagation of germs in the rice. When this intermittent heating step is completed, the control means 20 again shifts to a heat retaining step for maintaining the rice temperature at about 60 ° C.

  Further, in the heat insulation course, a reheating course for heating the rice to about 90 ° C. starts when the user arbitrarily presses the reheating input means 24. In the reheating course, the inner pot heating means 4 By heating the rice from the bottom and side surfaces through the pan 2, the temperature of the rice is raised to a predetermined temperature. When the rice is heated by the inner pot heating means 4 through the inner pot 2, the rice on the bottom and side surfaces in the vicinity of the inner pot 2 is first heated, and then the heat is gradually transferred to the upper middle rice in the inner pot 2. Thereafter, the rice is heated from the upper layer through the steam generated by the steam generating means 10. Thereby, heat can be supplied to the upper layer part from which heat is hard to reach from the inner pot 2, and it can heat more uniformly. When the rice temperature reaches about 90 ° C. based on the temperature detected by the inner pot temperature detecting means 6, the control means 20 stops heating the inner pot heating means 4, ends the reheating course after supplying steam, Move to the original warming course.

  Below, the discharge operation | movement of the vapor | steam containing the rice bowl by the structure in the rice cooker of Embodiment 1 of this invention in a cooking process is demonstrated using Fig.2 (a), (b).

  The opening of the steam discharge cylinder 15 through which steam containing a bowl generated in the inner pot 2 passes is closed by a steam valve 17 when the inner pressure in the inner pot 2 is equal to or lower than the target pressure. The lower end surface of the umbrella portion 16 of the steam valve 17 is located at a position lower than the contact portion between the steam discharge cylinder 15 and the steam valve 17 (FIG. 2B). When the pressure in the inner pot 2 reaches the target pressure, the steam valve 17 is lifted upward by the steam containing the rice bowl. At that time, the steam containing the rice bowl generated in the inner pot 2 is discharged all at once. It escapes from between the tube 15 and the steam valve 17 and is discharged to the outside of the rice cooker body 1. Also at this time, the lower end surface of the umbrella portion 16 of the steam valve 17 is always located at a position lower than the contact portion between the steam discharge cylinder 15 and the steam valve 17 (FIG. 2A). After this operation, when the internal pressure of the inner pot 2 falls below the target pressure, the steam valve 17 descends, covers the opening of the steam discharge cylinder 15 again, and blocks the steam flow including the pot ( FIG. 2 (b)). Since the cooking process is a process of cooking the food in the inner pot 2 with high heating power, the operation of the steam valve 17 described above is frequently repeated, and the steam containing the rice balls generated in the inner pot 2 is heated. We are discharging.

  Since the steam valve 17 has the umbrella portion 16 outside the steam discharge cylinder 15, the steam including the rice bowl once collides with the top surface of the steam valve 17 and further collides with the umbrella portion 16. After that, it is discharged as steam to the outside of the rice cooker body 1. In the above-mentioned collision process, the steam containing the rice cracker separates the rice cake and water vapor, and the steam released to the outside of the rice cooker body 1 is largely made up of water vapor. It can be prevented. Further, since the lower end surface of the umbrella portion 16 of the steam valve 17 is located at a position lower than the contact portion between the steam discharge tube 15 and the steam valve 17, the contact area of the steam valve 17 including the steam increases. In addition, the effect of separating the rice ball and the water vapor can be amplified.

  Further, as shown in FIG. 3, if the outer peripheral rib 23 or the like is provided on the umbrella portion 16 of the steam valve 17, a further barrier is provided to the steam containing the beak, so that The effect of prevention can be further enhanced.

  The separated rice balls are guided to the reflux port 18 on the bottom surface of the steam cylinder 14 and temporarily accumulate between the reflux port 18 and the reflux valve 19. When the weight exceeds a certain weight, the reflux valve 19 is bent downward, and the weight is lowered downward. Fall. In this way, rice balls can be collected again in the inner pot 2, and the rice cooking performance is also improved by not missing the umami component contained in the rice balls.

  In addition, when the contact portion of the steam valve 17 with the steam discharge cylinder 15 is made spherical as shown in FIGS. 1, 2, and 3, the steam valve 17 continuously and smoothly performs an operation close to a pendulum. Become. Such an operation of the steam valve 17 can keep the interlocking with the pressure change in the inner pot 2 and can easily move the steam valve 17 up and down in a very short period of time. It becomes possible to realize a pressure change that is close to the pressure fluctuation inside the pot in the cooking process. At the same time, it is possible to realize any position without specifying the steam discharge position between the steam valve 17 and the steam discharge cylinder 15 for the steam containing the rice cake, and the discharge of the steam containing the rice cake is regulated at a certain location. Therefore, it is possible to reduce the dynamic pressure at the time of releasing the steam containing the bean paste, and it is easy to prevent splashing and spilling due to the protrusion of the beef and the protrusion of the water vapor.

  Furthermore, since the steam valve 17 has the umbrella portion 16 and a barrier against steam including the beak is provided in the steam valve 17 itself, the stick is difficult to adhere within the movable range of the steam valve 17. The malfunction of the steam valve 17 due to sticking can be avoided. By this, it can be stabilized to the fixed operation | movement of the steam valve 17 from the early stage of rice cooking, the addition of the stable pressure can be implement | achieved, and stabilization of rice cooking performance can also be implement | achieved.

  Here, the pressure state of the steaming process and the taste of rice will be described with reference to FIG.

  Generally, in the steaming process for cooking firewood, the furnace attached to the firewood is opened and closed, and air is supplied to the combustibles in the furnace (generally wood, charcoal, rice husk) to adjust the thermal power. . When the furnace is open, that is, when a lot of air is supplied, the thermal power in the furnace becomes high, and when the furnace is closed, that is, when the air supply is shut off, the thermal power in the furnace becomes low. . The opening and closing of the furnace varies depending on the configuration of the firewood and the cook, but is adjusted to prevent the fire in the furnace from extinguishing.

When the furnace is opened, the casserole for storing the cooked food is heated from below by the high heating power, and the moisture of the rice in the lower layer inside the hood evaporates. At that time, the lower layer of rice in contact with the hank is burnt, and at the same time, the evaporated water reaches the upper layer, and heat is passed through each grain of rice in the upper layer to the core. The inside of the feather kettle at that time is kept constant during the steaming process with a moderate amount of water and a pressure value of 40 to 50 mmH ₂ O as shown in FIG. The principle will be described below. The wooden lid, which is a lid that covers the feather kettle, is extremely moisturizing and has low thermal conductivity compared to the feather kettle material (generally made of aluminum). There is little influence, the temperature distribution of the wooden lid can be kept almost uniform, and the amount of water in the upper layer space of the feather pot is kept almost constant without locally condensing on a part of the wooden lid. In addition, the hood and the wooden lid have a non-uniform gap with the outer periphery of the hood, and steam is not always discharged from the same part even when steam is discharged. Variation can be minimized. The discharge of the steam, is performed only when it becomes more than the pressure value of 40~50mmH 2 _O, nor emitted outward more than necessary moisture in Hagama.

  As mentioned above, heat is passed through each grain of rice in the upper layer of the hankama rice by the evaporated water of the lower layer of the hankama, and a slight pressure is constant on the rice inside the hankama with an appropriate amount of water without drying. By continuing to add for a period of time, the stickiness and flavor of rice cooked with salmon is pulled out. Moreover, the firepower fluctuation of the soot due to the opening and closing of the furnace depends on the state of the combustible material in the furnace, but may be several seconds, sometimes 1 second or less. That is, the characteristic of rice-boiled rice is that pressure fluctuations and water content fluctuations due to steam discharge inside the hood are repeatedly performed in a very short period of time, and this brings out the deliciousness of the rice-boiled rice.

  The operation when superheated steam is charged in the steaming process and the heat retaining process will be described below with reference to FIGS. 5 (a) and 5 (b).

The steam cylinder 14 includes a steam discharge cylinder 15 provided so as to protrude upward from the bottom thereof, and a steam valve 17 having an umbrella portion 16 positioned outside the steam discharge cylinder 15 above the steam discharge cylinder 15. It is installed in a state in which the opening of the steam discharge cylinder 15 is closed. For example, when the pressure value in the inner pot 2 is set to 50 mmH ₂ O, the steam valve 17 is configured so that the pressure in the inner pot 2 is superheated steam or the lower layer of rice in the inner pot 2 heated by the inner pot heating means 4. It is lifted upward only when it rises to 50 mmH ₂ O by the steam generated from (Fig. 5 (a)). At this time, a part of the superheated steam or a part of the steam is discharged to the outside of the rice cooker body 1. When the steam valve 17 releases superheated steam or steam to the outside of the rice cooker body 1, it immediately falls by its own weight and comes into contact with the opening of the steam discharge cylinder 15 (FIG. 5B).

The above-described operation is an operation that can be realized by having the steam valve 17. For example, when superheated steam is introduced without the steam valve 17, a part of the superheated steam is added to rice and water in the inner pot 2. It escapes as it is, and superheated steam cannot be efficiently sent into the inner pot 2, and the pressure in the inner pot 2 cannot be kept at 50 mmH ₂ O, which is the same as that for cooking rice. If the opening area of the steam discharge port 13 or the steam discharge tube 15 is reduced in order to maintain the internal pressure in the inner pot 2, spilling may occur in the rice cooking process as in the case of the rice cooking, and the steam discharge port 13 or steam. A means for reducing the opening area of the discharge cylinder 15 to keep the pressure in the inner pot 2 at a fine pressure cannot be taken.

However, since the rice cooker of Embodiment 1 of the present invention has the steam valve 17 that closes the opening of the steam discharge cylinder 15, the steam generated from the superheated steam or the lower layer of the rice fills the inner pot 2 and the inner pot. Since the steam valve 17 opens the steam discharge cylinder 15 and discharges the steam in the inner pot 2 only after the pressure in the pressure rises and reaches the target pressure (50 mmH ₂ O), the superheated steam is efficiently transferred to the inner pot. The superheated steam can be efficiently added to the rice in the inner pot 2 under the condition of being fed into ₂ and under a minute pressure (50 mmH ₂ O).

As an effect having the above-described configuration, in the steaming step, the pressure is 2 to 3 times / second under a pressure of 50 mmH ₂ O (a value corresponding to the pressure in the simmering pot) in the steaming step. It is very similar to the operation of the steaming process of steamed rice to perform the adjustment of the amount of water in the inner pot 2 by adding a small pressure in such a short time, superheated steam, and external discharge of steam, The pressure in the inner pot 2 and the amount of water are almost the same as the steaming process for cooking rice. The stickiness and flavor of the rice in the inner pot 2 can be pulled out to bring out the same deliciousness as rice cooked in the pot. become able to. In addition, since there is no flow path through which steam is continuously discharged, variations in moisture content and temperature distribution in the upper space in the inner pot 2 are reduced, and local condensation due to steam discharge is prevented. be able to.

  The following items can be cited as the effects of the heat retaining step. Cooked rice is the conversion of β-starch of rice into α-starch, that is, starch gelatinization (α-izing) reaction. This reaction is a reversible reaction, and rice after cooking is changed from α-starch to β-starch. The changing reaction of aging has progressed little by little since immediately after cooking. Since the progress of aging becomes prominent when the temperature is about 60 ° C. or lower, the heat retaining step is generally set to 60 ° C. or higher.

Aging of starch is a factor that causes a decrease in the taste of rice such as rice paste. In order to suppress the aging of the heat-insulating rice, that is, to promote gelatinization (alpha), conventionally, superheated steam has been added to the heat-insulated rice to improve the taste of the heat-insulated rice. By having the above-described configuration, all of the superheated steam is added to the rice in the inner pot 2 without waste until the superheated steam starts to be charged and the pressure in the inner pot 2 reaches the target pressure. Also, the superheated steam penetrates not only to the upper layer of the rice but also to the lower layer, the superheated steam is added to the whole rice in the inner pot 2, and the temperature of the rice is increased to 60 ° C. or higher with the moisture content maintained or increased. It becomes possible to gelatinize the starch of the heat-insulated rice, and the taste of the heat-insulated rice can be improved. This improvement in taste is particularly noticeable between the start of heat retention and 6 hours from when starch aging is not excessively accelerated.

  Moreover, since the superheated steam can be efficiently added to the rice as described above, the power consumed until the steam is generated can be minimized, and an energy saving effect can be obtained.

  Besides, when the steam is not charged, basically, the opening of the steam discharge cylinder 15 is in a closed state, and when the steam valve 17 releases the superheated steam to the outside of the rice cooker body 1, the weight falls immediately, Since it contacts and closes the opening of the discharge cylinder 15, the amount of steam discharged can be kept to a minimum, the moisture retention in the inner pot 2 is improved, and moisturized rice with a high moisture content is realized. become able to. Moreover, since the superheated steam and the water in the inner pot 2 can be released appropriately when the steam is added, the stickiness of the rice due to excessive water content does not occur.

  Moreover, since the invasion path | route of the bacteria in the air from the rice cooker main body 1 outside can be cut off, the heating amount of the inner pot heating means 4 for preventing the proliferation of the bacteria which rot rice is minimized. It is possible to prevent the rice from being deteriorated by heating and increase the power consumption.

  In addition, even when the use environment of the rice cooker is at a low temperature, the steam discharge port 13 and the inner pot 2 are not cooled by the atmosphere outside the rice cooker body 1, so the overheated steam is wasted. It can be added to rice without. Water droplets due to condensation do not occur in the vicinity of the steam outlet 13.

Furthermore, in order to realize the fine pressure in the steaming process of the above-mentioned rice cooked with rice cake, the rice cooker according to Embodiment 1 of the present invention can adjust the weight of the steam valve 17 and the opening area of the steam discharge cylinder 15. have. For example, when the weight of the steam valve 17 is 3.8 grams, the opening diameter of the steam discharge cylinder 15 is set to φ10.1 mm, and a fine pressure of 50 mmH ₂ O is realized. If it is possible to adjust the weight of the steam valve 17 with respect to the required pressure, the fine pressure applied to the rice in the inner pan 2 can be adjusted. Can be adjusted. Further, the same effect as described above can be obtained even if the opening area of the steam discharge cylinder 15 can be adjusted. In addition, in order to make use of the above-mentioned effect, the combination of the steam valve 17 and the steam discharge cylinder 15 at the time of rice cooking is set so that the same fine pressure (50 mmH ₂ 0) as that of the rice cooking is produced. It is good to change into the combination of the steam valve 17 and the steam discharge cylinder 15 which become the pressure suitable for the amount of moisture of a favorite, and heat retention performance.

  Moreover, since the pressure in the steaming process for cooking rice is very small, it may be affected by the altitude of the environment in which the rice cooker is used. In that case, it has a pressure adjustment means as mentioned above, and it becomes possible to suppress the fluctuation | variation of the rice cooking performance by changing the use environment of a rice cooker by adjusting pressure. In addition, calculation of the above-mentioned design numerical value is the value which found and extracted the correlation of a theoretical formula and an experimental result, and a numerical value changes with rice cooker structures.

  Moreover, when the steam valve 17 is configured to be detachable from the rice cooker body, there is an advantage that the weight of the steam valve 17 can be easily adjusted by creating a plurality of steam valves 17 having different weights. At the same time, the steam valve 17 can be easily cleaned and the rice cooker can be used in a sanitary manner.

Moreover, as shown in FIGS. 1, 2, 3, and 5, the contact portion of the steam valve 17 with the opening of the steam discharge cylinder 15 has a spherical shape. By adopting such a shape, the operation of the steam valve 17 described in the first embodiment can be made smooth. Such a smooth operation of the steam valve 17 can keep the interlocking with the pressure change in the inner pot 2 and can easily move the steam valve 17 up and down in a very short period of time. It becomes possible to realize a pressure change that approximates the pressure fluctuation inside the casserole in the steaming process of the steaming process. Moreover, since the phenomenon in which the steam valve 17 is caught by the steam discharge cylinder 15 can also be avoided, it becomes possible to prevent the superheated steam and steam in the inner pot 2 from being released more than necessary outside the rice cooker body 1.

  Moreover, when the steam discharge cylinder 15 has one or a plurality of cutout portions 25, the inner pot 2 can be used until the pressure in the inner pot 2 reaches the target pressure (slight pressure in cooking). It becomes possible to discharge the steam inside. This can prevent an abrupt pressure increase in the process until the target pressure in the inner pot 2 is reached, and can prevent impossibility of high pressure on the rice in the inner pot 2 (see FIG. 4). It has been shown that over-pressurizing can damage the taste of rice.)

  Further, even when the steam valve 17 is fixed, the steam can be discharged from the notch 25, a rapid pressure increase in the inner pot 2 can be prevented in each rice cooking process, and a safe rice cooker can also be used. It becomes like this.

  The rice cooker according to the present invention is useful as a rice cooker for home use or business use.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. (A) Steam valve vicinity principal part sectional drawing which showed the steam valve operation | movement in the cooking process of the rice cooker in Embodiment 1 of this invention (at the time of a steam valve raise) (b) Rice cooker in Embodiment 1 of this invention Cross section of the main part of the steam valve showing the steam valve operation in the cooking process (when the steam valve is lowered) Steam valve vicinity principal part sectional drawing which has an outer periphery rib in the steam valve of the rice cooker in Embodiment 1 of this invention. Correlation diagram of fine pressure and taste (A) Steam valve vicinity principal part sectional drawing which showed the steam valve operation | movement in the steaming process of the rice cooker of Embodiment 1 of this invention (at the time of a steam valve raise) (b) Of the rice cooker of Embodiment 1 of this invention Cross section of the main part of the steam valve showing the steam valve operation in the steaming process (when the steam valve is lowered) Cross-sectional view of a conventional rice cooker

DESCRIPTION OF SYMBOLS 1 Rice cooker main body 2 Inner pan 3 Lid 10 Steam generating means 13 Steam discharge port 14 Steam cylinder 15 Steam discharge cylinder 16 Umbrella part 17 Steam valve 21 Steam heating means 25 Notch

Claims (6)

A rice cooker body, an inner pot detachably stored in the rice cooker body, a heating means for heating the cooked food in the inner pot, a lid covering the opening of the inner pot, and the lid A steam outlet that is disposed and exhausts the steam in the inner pot to the outside, a steam cylinder provided in the steam outlet, steam generating means, and steam generated from the steam generating means is heated to 100 ° C. Steam heating means for making superheated steam exceeding the steam cylinder, and the steam cylinder closes the steam discharge cylinder protruding from the bottom of the steam cylinder and the steam discharge cylinder, and the outer periphery of the steam cylinder is outside the steam discharge cylinder. And a swingable steam valve having an umbrella portion whose lower end surface is lower than a contact portion with the steam discharge cylinder, and an outer peripheral rib projecting downwardly provided on the umbrella portion In the steaming process and the heat retaining process, the superheated steam is placed on the inner pot. Rice cooker is introduced into said inner bowl from. The rice cooker according to claim 1, wherein the weight of the steam valve is adjustable. The rice cooker according to claim 1 or 2, wherein an opening area of the steam discharge cylinder is adjustable. The steam cooker according to any one of claims 1 to 3, wherein the steam valve is detachable. The rice cooker according to any one of claims 1 to 4, wherein a contact portion of the steam valve with the steam discharge tube has a spherical shape. The rice cooker according to any one of claims 1 to 5, wherein the steam discharge tube has at least one notch.

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