JP2009183505A - Electric rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric rice cooker capable of increasing water content in rice by simple structure. <P>SOLUTION: The electric rice cooker 1 includes a pot 10 for storing material containing water and rice to be cooked, heating means (5, 6 and 19) for heating the material in the pot 10, a lid 11 for closing an opening of the pot 10 and a control device 9 for performing a cooking process including a water absorbing process in which the heating means is controlled so that the rice absorbs water. In the water absorbing process, the control device 9 increases an inner pressure of the pot 10 up to 1.05-1.18 atmospheric pressure so that the rice absorbs water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric rice cooker, and more particularly to an electric rice cooker that cooks rice by absorbing sufficient water into rice.

  In the water absorption process of the rice cooking process, it is known that even if the rice is immersed in room temperature water for a long time, the water content absorbed by the rice does not rise above a certain value. One of the factors is that rice has a structure in which starch inside is hard to absorb water surrounded by hard cells. If rice is cooked with a low water content, the cooked rice may be hard, non-sticky, and crisp, and may have a core. Therefore, in this water absorption step, the room temperature water is usually heated to a predetermined temperature, and the water content of the rice is increased by the heated water. However, when the temperature of the heated water exceeds a predetermined value, for example, 60 ° C. or higher, the starch of the rice starts to gelatinize and the surface of the rice is gelatinized first, and on the contrary, it is difficult for water to penetrate inside the rice. The rice cooker has been devised to increase the water content while preventing gelatinization of starch in the water absorption process (see, for example, Patent Documents 1 to 3 below).

  For example, the rice cooker disclosed in the following Patent Document 1 is provided with steam generating means to increase the water absorption speed. This rice cooker supplies steam from the steam generating means to the pot in the water absorption process where the rice absorbs water, that is, the water immersion process, and raises the temperature of the initial rice cooking temperature to a temperature at which gelatinization does not occur. Thus, the water absorption speed is increased by increasing the rise time of the water temperature. Moreover, the rice cooker disclosed by the following patent document 2 provides a preliminary | backup water immersion process before a normal water immersion process, and raises a moisture content. This preliminary submersion process uses steam generating means for generating steam heated to 100 ° C. or higher, and before the normal submersion process is started, this heated steam is injected into the pan to increase the moisture content, After this preliminary water immersion is completed, the process is shifted to a normal water immersion process. Furthermore, the rice cooker disclosed by the following patent document 3 is provided with the steam treatment process which makes the pressure in a pan higher than atmospheric pressure and absorbs water before a normal water immersion process.

  Next, with reference to FIG. 9, the rice cooker disclosed by this patent document 3 is demonstrated in detail. In addition, FIG. 9 is sectional drawing of the rice cooker disclosed by the following patent document 3. As shown in FIG.

This rice cooker 40 includes a pan 41 for storing rice, a steam generating means 43 for vaporizing water to generate steam, and a pressure adjusting means 44 for adjusting the pressure in the pan 41, and to a normal water immersion process. Before the transition, a steam processing step is performed. Specifically, first, rice and a small amount of water for steam generation are put in the pot 41, and the pot 41 is heated by the pot heating means 42 to evaporate the water and generate steam. At this time, the pressure adjusting means 44 closes the steam hole 44a so that steam is not released from the inside of the pan 41, so that the pressure in the pan 41 is increased from the atmospheric pressure. Next, since the internal force in the pan 41 is higher than the atmospheric pressure, the high-temperature steam at 100 ° C. or higher is rapidly cooled and condensed on the rice surface lower than 100 ° C., and water droplets adhere to the surface of the rice. The rice is heated by the heat of the steam and the heat of vaporization generated when the steam is liquefied, resulting in a surface state in which water is easily absorbed, and water droplets adhering to the rice surface are absorbed. Therefore, since the pressure in the pan 41 is increased, high pressure is also applied to water and rice, and this pressure makes it easy for water to pass through the rice cell wall, so that more water is absorbed by starch. Thereafter, the process shifts to a normal water immersion process, but the surface of the rice is heated to a high temperature after the steam treatment process, so that it is rapidly cooled by the water supplied in the normal water immersion process and becomes more easily absorbed. . Therefore, in this normal water immersion process, more water is absorbed than in the case where the steam treatment process is not performed.
JP 2003-144308 A (paragraphs [0021] to [0023], FIG. 1) JP 2005-168546 A (paragraphs [0025] to [0033], FIG. 2) JP 2007-151648 A (paragraphs [0041] to [0046], FIG. 1)

  According to the rice cooker disclosed by the said patent documents 1-3, each has a specific structure, A moisture content rises by these structures and can cook delicious rice. However, these rice cookers require a steam generating means as a new configuration, and a special preliminary water immersion process or steam treatment process in addition to the normal water immersion (water absorption) process is required. And control becomes complicated. For example, even if the rice cooker of the said patent document 1 raises the temperature of water to the temperature which gelatinization does not occur in the initial stage of rice cooking for a short time, and even if the water absorption speed of rice is made quick, the water absorption to the rice at the time of a water immersion process will be carried out. Not enough. Moreover, if the rice cooker of the said patent document 2 supplies a vapor | steam, a vapor | steam will be rapidly cooled and condensed on the rice surface, and a water droplet will adhere to the rice surface. And the rice surface will be in the state which is easy to absorb water by the calorie | heat amount etc. which a vapor | steam has, and more water droplets adhering to the rice surface are absorbed. However, although steam condenses on the rice surface and water droplets adhere, it cannot supply moisture to the starch inside the rice, and it is difficult to increase the moisture content inside the rice. Therefore, it is necessary to allow the rice to absorb water in the subsequent rice cooking process, and as a result, it is difficult to shorten the rice cooking time. Furthermore, the rice cooker of the said patent document 3 requires the water supply operation | work which must supply a predetermined amount of water when it transfers to a water absorption process, after a steam processing process is complete | finished. After completing the steam treatment process, open the rice cooker lid, feed the water while checking the amount of water corresponding to the amount of rice charged in the pan, and then close the lid and start the normal rice cooking process. It becomes work to let you. This work is troublesome because it cannot be automated and is manual. In addition, since this type of rice cooker heats the pot from the bottom and side walls of the pot, the water and rice adjacent to the bottom and side walls of the pot are heated at a predetermined temperature in the water absorption process. Since the temperature of the rice and water is lower than the temperature in the vicinity of the pot bottom and the side wall surface, there is a possibility that the water absorption varies between them, so-called uneven water absorption.

  The present inventors have been engaged in the development and commercialization of rice cookers for many years, and in recent years, in pressure-type rice cookers that cook rice by increasing the pressure in the pan to atmospheric pressure or higher, the pressure valve in the boiling maintenance step after the water absorption step The rice cooker that cooks rice by causing the so-called bumping phenomenon to reduce the pressure in the pan from high pressure to near atmospheric pressure and stir the rice vigorously in the pan, and commercialize it. Several patents have already been acquired in the invention (see, for example, Japanese Patent No. 3852293). For example, the pressure-type rice cooker disclosed in Japanese Patent No. 3852293 is a boil maintaining process of the rice cooking process, and the pressure valve is forcibly opened to reduce the pressure in the boiling pot to near atmospheric pressure at once. By doing this, a bumping phenomenon is generated in the pan, and the rice grains are controlled to be stirred and cooked.

  However, this rice cooker heated the inside of the pan in a state of opening the pressure valve, that is, without pressurizing the inside of the pan in the water absorption process. However, in this water absorption process, when the pressure valve was closed and heated at a predetermined temperature to increase the pressure in the pan to a predetermined pressure, it was found that the water content of rice increased. So, in the boiling maintenance process of this pressure rice cooker, the pressure in the pan is increased, so just using this mechanism as it is, just changing the control method of the control device with the existing rice cooker, The present invention has been completed with the idea that the voltage can be increased.

  That is, the present invention has been made in consideration of the above development situation while solving the above-described problems of the prior art, and an object of the present invention is to provide an electric rice cooker that can increase the moisture content of rice with a simple configuration. It is to provide.

  Another object of the present invention is to increase the water content of the rice in the water absorption process by changing the control method without changing the structure of the conventional rice cooker and without newly establishing a new rice cooking process. Another object is to provide an electric rice cooker that can eliminate uneven water absorption and cook delicious rice.

  In order to achieve the above object, the electric rice cooker according to claim 1 is a pan in which a cooked rice containing water and rice is accommodated, a heating means for heating the cooked rice in the pan, An electric rice cooker comprising: a lid that closes an opening of a pan; and a control device that performs a rice cooking process including a water absorption process for controlling the heating means to cause the rice to absorb water, wherein the control device includes the water absorption In the process, the internal pressure in the pan is increased to a predetermined value to cause the rice to absorb water.

  According to a second aspect of the present invention, in the electric rice cooker according to the first aspect, in the water absorption step, the control device controls the pressure in the pan to be in the range of 1.05 to 1.18 atm. Features.

  Invention of Claim 3 is the electric rice cooker of Claim 1 or 2, The pressure in the said pan is changed according to the amount of rice cooking in the said pan.

  According to a fourth aspect of the present invention, in the electric rice cooker according to the first aspect, the lid body has a steam discharge hole for releasing the steam in the pan to the outside, and a valve opening / closing for closing or opening the steam discharge hole. The control device operates the heating means in the water absorption step and closes the vapor discharge hole by the valve opening / closing mechanism to increase the internal pressure in the pan. To do.

  According to a fifth aspect of the present invention, in the electric rice cooker according to the fourth aspect, the steam discharge hole is also used as a pressure valve, and the valve opening / closing mechanism forcibly opens the pressure valve. In addition, in the boiling maintaining process of the rice cooking process, the control device is configured to control rice cooking by increasing the pressure in the pan to atmospheric pressure or higher.

  The invention according to claim 6 is the electric rice cooker according to claim 1, wherein the heating means is provided on a bottom heater that heats the bottom of the pan, a side heater that heats the side, and the lid body from above. And an upper heater for heating, wherein the control device controls at least a heating amount of the bottom heater in the water absorption step.

  This invention has the following outstanding effects by providing the said structure. That is, according to the invention of claim 1, by increasing the pressure in the pan to a predetermined value in the water absorption step, water is efficiently absorbed into the rice and the water content is increased. That is, when the pressure in the pan is increased, pressure is also applied to water and rice, and this pressure makes it easier for water to pass through the rice cell wall, so that more water is absorbed by rice starch. In addition, when a pressure is applied to the rice, a small crack is formed in the rice, water penetrates into the inside of the rice, and water is supplied to the starch in the center of the rice through the gap between the rice cell walls. The rate goes up. Furthermore, there is no variation in water absorption in the pan, so-called uneven water absorption.

  According to invention of Claim 2, since the pressure in a pan is set to the range of 1.05-1.18 atmospheres, without making the surface of rice gelatinize and producing water absorption nonuniformity, In addition, the rice can absorb sufficient water efficiently and efficiently. This pressure range was confirmed by experiments.

  According to invention of Claim 3, by changing the pressure in a pan according to the amount of rice cooking, sufficient water can be absorbed into rice effectively and efficiently.

  According to the invention of claim 4, the pressure in the pan can be easily increased simply by closing the vapor discharge hole during the water absorption step.

  According to the invention of claim 5, the steam discharge hole is also used as a pressure valve, and the valve opening / closing mechanism is also used as a pressure valve opening mechanism for forcibly opening the pressure valve. It is possible to cook rice that exhibits the above-described effects in the pressure rice cooker by simply changing the control method without changing the structure of the above and without newly establishing a new rice cooking process.

  According to the invention of claim 6, since the heating means is provided with the bottom heater for heating the bottom of the pan, the side heater for heating the side and the upper heater for heating from the upper side provided on the lid, the control device In the water absorption step, the pressure in the pan can be increased to a predetermined value by controlling at least the heating amount of the bottom heater. Moreover, if the heating amount of all the heaters is controlled, the pressure in the pan can be increased to a predetermined value more efficiently.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a pressure rice cooker (hereinafter simply referred to as “rice cooker”) as a rice cooker for embodying the technical idea of the present invention. It is not intended to be specific to the device, and other embodiments within the scope of the claims are equally applicable.

  Hereinafter, with reference to FIGS. 1-4, the rice cooker provided with the rice cooking amount determination means which concerns on one Embodiment of this invention is demonstrated. 1 is a front view of a rice cooker according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the rice cooker of FIG. 1, FIG. 3 is an enlarged view of the pressure valve opening mechanism of FIG. 2, and FIG. It is an enlarged view of X part.

  As shown in FIGS. 1 and 2, the rice cooker 1 includes a pan 10 into which a cooked rice containing rice and water is put, an opening in which the pan 10 is accommodated, and the pan 10 inside. A rice cooker main body (hereinafter referred to as a main body) 2 having a bottom heater 5 and a side heater 6 that heats and heats the cooked food, and is pivotally supported on one side of the main body 2 so as to cover the opening of the main body 2 and to be closed A lid 11 having a locking mechanism 21 to be locked, a pressure valve 13 that is attached to the lid 11 and adjusts the pressure in the pan 10, a pressure valve opening mechanism 15 that controls opening and closing of the pressure valve 13, and rice cooking Display operation unit 8 for performing operations such as starting, timer reservation and heat retention, and heating means and pressure having bottom heater 5 and side heater 6 and inner lid heater 19 to be described later according to a rice cooking start signal from display operation unit 8 Control for controlling the valve opening mechanism 15 and the like And a location 9.

  The control device 9 is provided with storage means. The storage means heats the cooked rice in the pan 10 to a predetermined temperature, and absorbs a predetermined amount of water over the predetermined time. Process, rising heating process for heating and heating the absorbed cooked rice until it boils, boiling maintaining process for maintaining the cooked rice in a boiling state, steaming process for steaming the cooked rice after the boiling maintaining process, The rice cooking and the heat retention program which perform sequentially the heat retention process etc. which heat-retained the cooked rice cooked after the steaming process at predetermined temperature are memorize | stored. Among these rice cooking processes, in the start-up heating process and the boiling maintenance process, the cooking process is executed by increasing the pressure in the pan to atmospheric pressure or higher, for example, about 1.1 to 2.2 atmospheres. Moreover, the data which linked | related the pressure value and the amount of rice cooking are memorize | stored in this memory | storage means.

  The main body 2 is composed of a bottomed box-type outer case 3 and an inner case 4 which is accommodated in the outer case 3 and in which the pot 10 is accommodated, and a gap is formed between the outer case 3 and the inner case 4. And a control circuit board constituting the control device 9 is disposed in the gap. The inner case 4 is provided with a bottom heater 5 at the bottom 4a and a side heater 6 at the side 4b. As the bottom heater 5, an electromagnetic induction coil wound in a donut shape is used. As the side heater 6, a heater in which a heating wire is covered with a heat-resistant member is used. The bottom 4a is provided with a pan bottom temperature sensor 7 composed of a thermistor for detecting the pan bottom temperature.

  As shown in FIG. 1, the main body 2 is provided with a display panel 8 a that displays various rice cooking menus on the front surface 2 a and a display operation unit 8 that includes operation buttons for selecting the rice cooking menu.

  As shown in FIG. 2, the pan 10 is made of a relatively deep bottom container into which a predetermined amount of rice to be cooked made of rice and water is put, and is made of a clad material of aluminum and stainless steel.

  As shown in FIG. 2, the lid 11 includes an inner lid 12 that closes the opening of the pot 10, an outer lid 20 that closes the entire opening of the main body 2, and the like. One end of the lid 11 is pivotally supported on one end of the main body 2 by a pivot 11 </ b> A, and the other end is locked to the other end of the main body 2 by a lock mechanism 21. The lid 11 is provided with a pressure detection means 26 for detecting the pressure in the pan 10. The pressure detection means 26 includes a pressure sensor 27 that converts pressure into an electrical signal, and the pressure sensor 27 is provided on the outer lid 20 of the lid body 11.

The inner lid 12 has a pressure valve 13 at its upper part, a pressure valve opening mechanism 15 for forcibly opening the pressure valve 13, and the pressure in the pot 10 when the pressure in the pot 10 rises to an abnormal pressure of a predetermined value or more. A safety valve V ₁ for releasing steam to the outside, an inner lid heater (also referred to as an upper heater) 19 for heating the inside of the pan 10 from above, and the like are provided.

Among these components, the inner lid heater 19 is a heater in which a heating wire similar to the side heater 6 is covered with a heat-resistant member. 2 and 4, the pressure valve 13 is mounted on the valve seat 13a in which a valve hole 13 ₁ having a predetermined diameter is formed and the valve hole 13 ₁ is closed. And a cover 13b that restricts the movement of the ball 14 and holds it on the valve seat 13a. The ball 14 has a predetermined weight, by its own weight, to close the valve hole 13 _1.

  As shown in FIG. 3, the pressure valve opening mechanism 15 includes a cylinder 15a around which an electromagnetic coil is wound, a plunger 15b that slides in the cylinder 15a by excitation of the electromagnetic coil and moves the ball 14, and the plunger It comprises a spring and an operating rod 15b 'mounted on the tip of 15b. The operating rod 15b 'is supported by a sealing member 15c having elasticity.

The pressure valve opening mechanism 15 is controlled by the control device 9. That is, when the electromagnetic coil is excited based on a command from the control device 9, the plunger 15b protrudes from the cylinder 15a, the operating rod 15b 'collides with the ball 14, and pushes the ball 14 in the lateral direction. By this extrusion, the ball 14 is moved from above the valve seat 13a to forcibly open the valve hole 13 ₁ . Further, in this open state, when the excitation to the electromagnetic coil is stopped, the plunger 15b is pulled back into the cylinder 15a by a spring force. the ball 14 returns to the valve seat 13a by its own weight, the valve hole 13 ₁ is closed by the ball 14. A steam temperature sensor S for measuring the temperature of steam ejected from the valve hole 13 ₁ is attached to the upper part of the pressure valve 13.

  The inner lid 12 is fitted with an inner lid packing 18 on the outer periphery thereof so as to be in contact with the opening of the pan 10 and sealed. As shown in FIG. 4, the inner lid packing 18 has a circular hole 18 </ b> A having a diameter slightly smaller than the diameter of the disk-shaped inner lid 12 and a ring-shaped attachment on the outer peripheral edge of the inner lid 12. It has a mounting portion 18B that is attached via the frame 16, and a seal portion 18C that comes into contact with the opening of the pan 10 and seals the opening, and is composed of a ring having a donut shape as a whole, and has high heat resistance and elasticity. It is formed with the silicon material which has.

  The mounting portion 18B has a concave groove 18B 'in which the ring-shaped mounting frame 16 is mounted, and is formed on the outer periphery of the circular hole 18A. The concave groove 18B 'is erected at a substantially right angle upward from an end portion of the groove bottom 18a on the side of the circular hole 18A and a substantially flat annular groove bottom 18a extending outward from the circular hole 18A. It is comprised by the cylindrical wall 18b and extension part 18a 'extended from the groove bottom part 18a. The cylindrical wall 18b is formed with a hook-like locking claw 18b 'that protrudes outward from its top and has its tip bent downward.

The seal portion 18C further extends from the extending portion 18a ′ of the groove bottom portion 18a and is formed in a substantially U shape. The U-shaped seal portion 18C is formed by a spring piece portion 18d extending from the extending portion 18a ′ and corresponding to the U-shaped bottom portion, and an elastic seal portion 18e extending from the spring piece portion 18d. . The elastic seal portion 18e has a tip contact portion 18 ₁ that contacts the inner wall 10a of the pan 10 and an intermediate contact portion 18 ₂ that contacts the curved portion 10b between the inner wall 10a and the pan flange 10c.

The mounting frame 16 is fitted into the concave groove 18B ′ and contacted with the surface of the groove bottom 18a, a body 16b extending upward from the bottom 16a, and a flat provided on the body 16b. And a ring frame having a donut shape as a whole, and is formed of a resin molded body having high heat resistance and predetermined mechanical strength. The mounting frame 16, the flat surface of the top portion 16c, the female screw hole 16 ₁ hanging down toward the bottom portion 16a is engraved from the flat surface. Also, the locking groove 16 ₂ is formed on the flat surface of the top portion 16c. Further, an H-shaped engaging portion 16b ′ having a locking groove 16 ₃ is formed on the side surface of the body portion 16b, that is, on the surface side of the cylindrical wall 18b. The 'A locking groove 16 _3, the locking claw 18b provided on the top of the cylindrical wall 18b' H-type engagement portion 16b of is locked.

To attach the inner lid packing 18 to the inner lid 12, first, the ring-shaped attachment frame 16 is attached to the inner lid packing 18. For this mounting, the ring-shaped mounting frame 16 is placed on the top of the cylindrical wall 18b of the inner lid packing 18, and the mounting frame 16 is pressed downward. By this pressing, the cylindrical wall 18b is bent inward by its elastic force, and insertion of the mounting frame 16 downward is allowed. When the bottom portion 16a of the mounting frame 16 is pressed to a position where it contacts the bottom surface of the concave groove 18B ', the restoring force of the cylindrical wall 18b returns to the original position, and the top of the cylindrical wall 18b is locked at this timing. The claw 18b ′ is locked in the engaging groove 16 ₃ of the H-shaped engaging portion 16b ′. By this locking, the inner lid packing 18 is fixed to the mounting frame 16. Then, the inner lid gasket 18 is fixed by screwing the female screw hole 16 ₁ in the male screw 17 provided at the contact is allowed to the outer peripheral edge to the outer peripheral edge of the inner lid 12 and mounting frame 16 fixed.

  According to the inner lid packing 18, the U-shaped seal portion 18C has a spring piece portion 18d corresponding to the U-shaped bottom portion, and an elastic seal extending from the spring piece portion 18d. When the opening of the main body 2 is closed with the lid 11, the elastic sealing portion 18 e of the sealing portion 18 C resists the spring force of the spring piece portion 18 d and the inside of the pot 10. Airtightness is ensured by being in close contact with the wall surface 10a and the curved portion 10b. Therefore, there is almost no steam leakage from the inside of the pan 10, and the loss of heat energy can be suppressed to a minimum, thereby saving energy. Further, since the inner lid packing 18 is fixed to the inner lid 12 with the attachment frame 16 interposed therebetween, the inner lid packing 18 is supported by the attachment frame 16 having a high mechanical strength. Is firmly fixed. Further, since the mounting frame 16 and the inner lid packing 18 can be mounted and removed without using a tool, the old inner lid packing 18 can be easily replaced.

  As shown in FIG. 2, the outer lid 20 is formed of a decorative cover that covers the inner lid 12, the pressure valve 13 attached to the inner lid 12, the pressure valve opening mechanism 15, and the like. The outer lid 20 is provided with a release button 22 for releasing the lock mechanism 21 of the lid 11 at one end, and a mounting hole 24 at the other end on the pivot 11A side. The mounting hole 24 is a bottomed recessed hole having a size that allows the storage cap 25 to be detachably inserted, and is formed in the frame 23 that supports the outer lid 20. In addition, the mounting hole 24 is formed with a mounting hole 24a into which a discharge cylinder 25a of a to-be-stored cap 25 described later is press-fitted. An annular seal member is attached to the mounting hole 24a so as to be in pressure contact with the outer peripheral surface of the discharge cylinder 25a so that the steam in the pan 10 does not leak to the outside.

For example, the storage cap 25 includes a discharge cylinder 25a that discharges, for example, steam discharged from the pressure valve 13, a vacant chamber 25b that stores a snack of umami components, and a steam discharge port 25c that discharges steam to the outside. And a return valve V ₂ for returning the stored spring into the pot 10 is provided at the bottom of the empty room 25b. When the steam is ejected from the pressure valve 13, the rice balls that are umami components are led out from the pot 10 through the pressure valve 13 together with the steam and are stored in the empty chamber 25 b of the storage cap 25. Is done. Oneba reserved in the Check 25b returns valve V ₂ if Ne Contact at a predetermined timing while open, is returned to the pan 10 in accordance with opening of the negative pressure valve provided in the inner lid 12 (not shown).

  The pressure detection means 26 has a detection hole (not shown) provided in the inner lid 12 and a pressure sensor 27 provided corresponding to the detection hole. The detection hole and the pressure sensor 27 are located in the pot 10. Are elastically pressed by a cylindrical body 28 having elasticity so that steam generated in the above does not leak to the outside. That is, when the inner lid 12 is attached to the outer lid 20, the cylindrical body 28 connects the detection hole and the pressure sensor 27 by elastic contact so that steam or the like does not leak. The pressure detection means is not limited to the above-described means, and may be detected based on, for example, the amount of change of the inner lid 12, that is, the amount of change when the inner lid 12 is lifted due to the increase of the pressure in the pan 10. It may be possible to detect by any means.

  Next, the configuration of the control device 9 will be described with reference to FIG. FIG. 5 is a control block diagram constituting the control device.

  The control device 9 includes a CPU that performs various arithmetic processes, a storage unit that includes a ROM and a RAM that stores various data, a rice cooking menu detection circuit that detects a selected rice cooking menu, a rice cooking amount determination unit, and an opening / closing of the pressure valve 13. In order to control a valve opening / closing timer in which time is set, a counter for counting the number of times the pressure valve 13 is opened / closed, a heating control circuit for controlling the heating temperature and heating time in the pan 10, and a display screen displayed on the display panel 8a Display panel control circuit, a pressure valve opening mechanism drive circuit for driving the pressure valve opening mechanism 15 to control the opening / closing timing of the pressure valve 13, and the like.

  The storage means stores rice cooking programs corresponding to various rice cooking menus. As described above, this rice cooking program is a water absorption process, a start-up heating process, a boiling maintenance process, a steaming process, an additional cooking process, and a heat retaining process after the completion of these rice cooking processes. Moreover, the data which linked | related the pressure value and the amount of rice cooking are memorize | stored in this memory | storage means. As shown in FIG. 8 (b), this data is large, medium, and small in the amount of cooked rice with respect to the pressures P1, P2, and P3. Of course, it is good also as the data which subdivided pressure P1-P3 and divided the amount of rice cooking corresponding to this pressure. The relationship between this pressure value and the amount of cooked rice has been determined by experiments.

Various commands are input to the control device 9 from the menu key 8 ₁ , start key 8 ₂ , reservation key 8 _3, etc. of the display operation unit 8. Similarly, detection values are input from the pan bottom temperature sensor 7, the steam temperature sensor S, the pressure sensor 27, and the like. In addition, the bottom heater 5, the side heater 6, the inner lid heater 19, the display panel 8a, the pressure valve opening mechanism 15 and the like are connected to this apparatus.

  Mainly with reference to FIGS. 5-8, the determination of the amount of rice cooking and a rice cooking process are demonstrated. 6 is a chart showing the temperature and pressure change in the pan, pressure valve control, heater control, etc. in the rice cooking process, and FIG. 7 is a pressure curve diagram showing the relationship between the pressure in the pan and the amount of rice cooked in the water absorption process. FIG. 8A is a table showing the moisture content measured at a predetermined position in the pan, and FIG. 8B is a table showing the relationship between the pressure value and the amount of cooked rice.

  First, when a predetermined menu is selected from the rice cooking menu displayed on the display panel 8a and the display operation unit 8 is operated, the control device 9 performs the bottom heater 5 and the side heater according to the selected rice cooking program. 6 and the pressure valve opening mechanism 15 to heat the cooked rice in the pan 10 to a predetermined temperature, and to absorb a predetermined amount of moisture over the predetermined temperature and time, Start-up heating process II for heating and heating the absorbed cooked rice until it boils, boiling maintenance process III for maintaining this cooked rice in a boiling state, and steaming process IV for steaming the cooked rice after this boiling maintenance process III Execute.

In the water absorption process I, the control device 9 closes the pressure valve 13 and controls the heating amount of the bottom heater 5, the side heater 6 and the top heater 19 in this state, so that the inside of the pot 10 has a predetermined water absorption temperature, for example, The water is absorbed by the rice at 60 ° C. When the pressure valve 13 is heated in a closed state, the pressure P in the pan 10 rises along a pressure curve corresponding to the amount of cooked rice, as shown in FIG. It was confirmed that the water content of the rice increased as the pressure in the pan 10 increased. That is, when the moisture content of each part was measured as a bottom A near the bottom of the pot, an intermediate part B higher than the bottom, and an upper part C above the intermediate part in the pot 10 of FIG. As shown in FIG. 8A, the bottom A is a ₁ , the middle B is a ₂ and the upper C is a ₃ , and the average value thereof is a _E. This average value was increased by 1.0% or more compared to that without boosting.

Therefore, in the water absorption step I, the pot 10 is heated to a predetermined temperature and the internal pressure is increased so that the water is absorbed by the rice, so that sufficient water can be effectively and efficiently produced without causing uneven water absorption. The rice can absorb water. That is, by raising the pressure in the pot 10, water and rice are also pressurized, and this pressure makes it easier for water to pass through the rice cell wall, so that more water is absorbed by the starch of rice. In addition, when a pressure is applied to the rice, a small crack enters the rice, water penetrates into the rice from there, and water is supplied to the starch in the center of the rice through the gap between the rice cell walls, Increases moisture content. In addition, in this water absorption process I, the relationship between the pressure value P in the pan 10 and the amount of rice cooking was calculated | required by experiment. As a result, as shown in FIG. 7, when the amount of cooked rice is small, these relationships rise steeply from the beginning and become substantially constant at a high pressure value P3 and saturate as shown in the pressure curve X _3. when many rice amount, as the pressure curve X _2, saturated at a substantially constant value at the rising dull lower pressure value P1, further, when the rice amount of these intermediate amount, the pressure curve X ₂ is It was located between the pressure curves X ₁ and X ₃ and became a value saturated at a substantially constant value at the intermediate pressure value P2. The pressure value P is in the range of 1.05 to 1.18 atmospheres, and cooking of the pressure curve X ₁ to X ₃ is a curve X ₁ is 5.5 cup, curve X ₂ 3.3 cup, curve X ₃ 0.5 cups, are sequentially large, medium, a cooking of small. And when the moisture content of the rice was measured when the pressure value became substantially constant (saturated) in each of the pressure curves X _{1 to} X ₃ , the result of FIG. 8 was obtained, and these contents a ₁ to The value a _E obtained by averaging a ₃ was increased by 1.0% or more compared to the value a _{E that} was not boosted. The relationship between the pressure in the pan 10 and the amount of cooked rice is stored in advance in the storage means. Moreover, the relationship between the moisture content and the amount of cooked rice is high when the amount of cooked rice is large, and decreases as the cooked rice is small. Yes.

  This pressure value P is detected by the pressure sensor 27. This detected value is input to the rice cooking amount determination means, and is compared with the rice cooking amount data stored in the storage means to determine the rice cooking amount.

Therefore, since the pressure value at the stable time point of each pressure curve X _{1 to} X ₃ shown in FIG. 7 corresponds to the amount of cooked rice on a one-to-one basis, the amount of cooked rice can be easily determined by detecting this pressure value. The determination can be made accurately, and the determination of the amount of cooked rice is accurate without being affected by the initial water temperature.

  In the next start-up heating process II, the heating amount of the heating means is controlled based on this rice cooking amount. In this process, the pressure in the pot 10 is increased to 1.2 atmospheres, for example.

  In the start-up heating process II, since the accurate amount of cooked rice is determined in the water absorption process I, from the initial stage of the start-up heating process II, heating is performed with an appropriate amount of electric power based on the accurate amount of cooked rice. Therefore, since the temperature rise degree of the start-up heating process II can be freely set by accurately determining the amount of cooked rice, it becomes easy to make a difference in cooking level such as hard and soft. Therefore, it can be cooked deliciously with your favorite rice cooking characteristics, such as your favorite hardness.

Further, in the boiling maintenance step III, the pressure valve 13 is forcibly opened once or a plurality of times to reduce the pressure in the boiling pot 10 at a stroke so as to be close to the atmospheric pressure. The opening of the pressure valve 13 causes a bumping phenomenon in the pan 10, and the rice is vigorously stirred. In addition, when the pressure valve 13 is opened, the umami component generated in the pan 10 is temporarily stored in the storage cap 25 through the pressure valve 13. The rice balls stored in the storage cap 25 are returned to the pot 10 by opening the return valve V ₂ at a predetermined timing.

  When this rice cooking process is completed, the instruction from the display operation unit 8 is automatically transferred to the heat retaining process. In this heat insulation process, the control device 9 keeps the inside of the pan 10 at a predetermined time and at a predetermined temperature. In this time zone, the control device 9 intermittently controls on / off of the bottom heater 5, the side heater 6, and the inner lid heater 19 to control the temperature at a predetermined temperature, for example, 70 ° C. or higher. By this heat retention control, the dew condensation on the inner wall of the pan 10 is reduced and the heat is kept at an optimum temperature.

  As mentioned above, although the pressure type rice cooker of one Embodiment of this invention was demonstrated, this invention is not limited to this pressure type rice cooker, It can apply also to a normal non-pressure type rice cooker. . Since the non-pressure rice cooker is provided with a steam discharge hole for discharging the steam in the pan to the outside, the above-described effects can be obtained by providing an opening / closing mechanism for opening and closing the steam discharge hole in the steam discharge hole. A rice cooker can be configured.

FIG. 1 is a front view of a pressure rice cooker according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the pressure rice cooker of FIG. FIG. 3 is an enlarged view of the pressure valve opening mechanism of FIG. FIG. 4 is an enlarged view of a portion X in FIG. FIG. 5 is a control block diagram constituting the control device. FIG. 6 is a characteristic diagram showing changes in temperature and pressure in the rice cooking process. FIG. 7 is a pressure curve diagram showing the relationship between the pressure in the pan and the amount of cooked rice in the water absorption process. Fig.8 (a) is the table | surface which showed the moisture content measured in the predetermined position in a pan, FIG.8 (b) is the table | surface which showed the relationship between a pressure value and the amount of rice cooking. FIG. 9 is a longitudinal sectional view of a conventional rice cooker.

Explanation of symbols

1 (Pressure type) rice cooker (electric rice cooker)
2 (rice cooker) body 3 outer case 4 inner case 5 bottom heater 6 side heater 7 pan bottom temperature sensor 8 display operation unit 9 control device 10 pan 11 lid 12 inner lid 13 pressure valve 14 ball 15 pressure valve release mechanism 16 mounting frame 18 Inner lid seal 19 Inner lid heater (upper heater)
20 outer lid 25 large storage cap 26 pressure detection means 27 pressure sensor

Claims (6)

A pot in which the rice to be cooked containing water and rice is accommodated, a heating means for heating the cooked rice in the pot, a lid for closing the opening of the pot, and the heating means to control the rice In an electric rice cooker equipped with a control device that performs a rice cooking process including a water absorption process for absorbing water,
The said control apparatus raises the internal pressure in the said pan to a predetermined value in the said water absorption process, and makes rice absorb water, The electric rice cooker characterized by the above-mentioned.   2. The electric rice cooker according to claim 1, wherein, in the water absorption step, the control device controls the pressure in the pan in a range of 1.05 to 1.18 atm.   The electric rice cooker according to claim 1 or 2, wherein the pressure in the pan is changed according to the amount of rice cooked in the pan.   The lid is provided with a steam discharge hole for releasing the steam in the pan to the outside, and a valve opening / closing mechanism for closing or opening the steam discharge hole, and the control device is configured to perform the heating in the water absorption step. 2. The electric rice cooker according to claim 1, wherein the steam cooker is closed by the valve opening / closing mechanism to increase the internal pressure in the pan while operating the means.   The steam discharge hole is also used as a pressure valve, the valve opening / closing mechanism is also used as a pressure valve opening mechanism for forcibly opening the pressure valve, and the control device is used in the boiling maintaining process of the rice cooking process. The electric rice cooker according to claim 4, wherein the inside of the pan is boosted to atmospheric pressure or higher to control rice cooking.   The heating means includes a bottom heater that heats the bottom of the pan, a side heater that heats the side, and an upper heater that is provided on the lid and heats from above. The electric rice cooker according to claim 1, wherein at least a heating amount of the bottom heater is controlled.

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