JP3925367B2 - Cooked rice incubator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooked rice warmer that suppresses yellowing of cooked rice and deterioration of physical properties during eating, and can provide delicious cooked rice even when kept warm.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as this kind of cooked rice incubator, one having a decompression device that decompresses air in an inner pot (rice cooker) and a gas separation membrane that allows only oxygen in the air to pass through is known (for example, a patent) Reference 1).
[0003]
This is provided with a gas separation membrane that allows only oxygen in the air to pass through at the front stage of the decompression device, and by operating the decompression device, the air in the inner pot is exhausted to the outside through the gas separation membrane. It reduces the absolute amount of oxygen. As a result, yellowing of the cooked rice during the heat insulation and the generation of the heat insulation odor were prevented.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-154039
[Problems to be solved by the invention]
However, the conventional cooked rice warmer has a configuration in which the air in the inner pot is discharged by the decompression device, and the inner pot is required to have a high degree of hermeticity, and the high degree of hermeticity can be maintained for a long time. It is difficult to say that it is suitable for general household use.
[0006]
The present invention solves the above-described conventional problems, and provides a cooked rice warmer that suppresses yellowing of rice and deterioration of physical properties during eating with nitrogen-enriched air, and provides delicious cooked rice even when kept warm. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the cooked rice warmer of the present invention comprises a nitrogen supply means for removing oxygen contained in the atmosphere and supplying a nitrogen-enriched gas, and a nitrogen storage means for storing the nitrogen-enriched gas. And a control means for controlling the supply amount of nitrogen, and the control means controls the supply amount of nitrogen-enriched gas from the nitrogen storage means to the inner pot.
[0008]
As a result, the unpleasant warming odor generated in the inner pot due to the supply of nitrogen-enriched gas is scattered, and the yellowing of the cooked rice and the deterioration of the physical properties during the taste can be suppressed. Can be provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is an inner pot for storing cooked rice, an openable / closable lid provided above the inner pot, a heating means for heating the cooked rice in the inner pot, and detecting the temperature of the inner pot. Temperature detection means for removing oxygen contained in the atmosphere and supplying nitrogen-rich gas to the inner kettle, gas transport means for carrying the nitrogen-rich gas, and from the nitrogen supply means Nitrogen storage means for storing nitrogen-enriched gas, and heating control of the cooked rice to a predetermined temperature using the heating means based on the detection value of the temperature detection means, and from the nitrogen storage means to the inner pot The rice cooker is provided with a control means for controlling the supply amount of the nitrogen-enriched gas, so that the unpleasant warming odor generated in the inner pot by the supply of the nitrogen-enriched gas is scattered, Can suppress yellowing and deterioration of physical properties during eating And it is also possible to provide a delicious cooked rice.
[0010]
The invention according to claim 2 is provided with a valve between the nitrogen supply means, the inner pot, and the nitrogen storage means. During rice cooking, the valve supplies the nitrogen supply means and the nitrogen storage means to each other, and after the rice cooking is finished, the valve In the rice cooker according to claim 1, wherein the nitrogen storage means and the inner pot are electrically connected to each other, the nitrogen-enriched gas stored in the nitrogen storage means after rice cooking is supplied into the inner pot, The oxygen concentration can be quickly reduced. For this reason, the oxygen concentration in the inner pot can be kept low, and the warming odor and yellowing of the cooked rice can be prevented, and the deterioration of the taste can be prevented.
[0011]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
FIG. 1 shows a jar rice cooker incorporating a rice cooker in an embodiment of the present invention. In the figure, reference numeral 1 denotes an inner pot installed in the main body 2, which heats and cooks a predetermined amount of cooked rice and water. A temperature detecting means 4 for detecting the temperature of the inner hook 1 is provided at the bottom of the inner hook 1 so as to be in contact with the inner hook 1, and a heating means comprising an electromagnetic induction heating coil for heating the inner hook 1. 5 is provided.
[0013]
6 controls the heating temperature of the cooked rice to a predetermined temperature using the heating means 5 based on the detection value of the temperature detection means 4 and the amount of nitrogen-enriched gas supplied from the nitrogen storage means (described later) to the inner pot 1. It is a control means for controlling, and is also provided with a high frequency power source for supplying power to the heating means 5.
[0014]
Reference numeral 7 denotes a heating means for heat insulation provided at the upper part of the side portion of the inner pot 1.
[0015]
Reference numeral 8 denotes an openable / closable lid provided above the inner hook 1, and the lower heat sink 9 is provided with a heating means 10 for the lid and a temperature detecting means 11 for the lid for detecting the temperature of the inner hook 1. It has been. The heating means 7 is heated and controlled by the control means 6, and the value detected by the temperature detection means 11 is input to the control means 6.
[0016]
Further, the lid 8 has a nitrogen supply means 15 for removing oxygen contained in the atmosphere and supplying a nitrogen-enriched gas, gas transport means 16a and 16b comprising pumps and fans for carrying the gas, and nitrogen enrichment. Nitrogen storage means 17 for storing various gases is provided. By operating the gas transport means 16a or 16b and exhausting the internal gas from the inner pot 1 or the nitrogen storage means 17 as shown by the arrow a, the external air is supplied with nitrogen as shown by the arrow b through the opening of the lid 8. It is led to the means 15 and separated into nitrogen and oxygen by the nitrogen supply means 15, and the oxygen is released to the outside through the nitrogen supply means 15 again from the opening as indicated by the arrow c.
[0017]
On the other hand, the separated nitrogen is mixed again with the atmosphere to become a nitrogen-enriched gas, and is introduced into the inner pot 1 or the nitrogen storage means 17 by the gas transport means 16a or 16b, respectively. The inner pot 1 is quickly replaced with nitrogen-enriched gas by the nitrogen supply means 15 or the nitrogen storage means 17, and the gas containing high-concentration oxygen existing in the inner pot 1 is opened by the gas transport means 16a. It is discharged to the atmosphere through. The opening through which the gas in the inner pot 1 is discharged to the atmosphere also functions as a steam vent during rice cooking.
[0018]
A check valve is provided so that a gas containing high-concentration oxygen does not flow backward from the inner pot 1 to the nitrogen supply means 15, and a valve 18 is provided between the nitrogen supply means 15, the nitrogen storage means 17 and the inner pot 1. Is provided so that the nitrogen supply means 15 and the inner pot 1 can be isolated.
[0019]
Therefore, since water vapor and rice balls generated by rice cooking do not adhere to the nitrogen supply means 15 and the gas transport means 16b, the nitrogen supply capability can be maintained for a long time, and water condensed on the piping, the nitrogen supply means 15 and the like can be maintained. It does not accumulate and is less likely to rot and keeps the cooked rice incubator clean for a long time. At the same time, the oxygen concentration in the inner pot 1 can be efficiently kept low at all times.
[0020]
An operation panel 12 is provided at the top of the lid 8, and an open / close detection means 19 is provided at a place where the main body 2 and the lid 8 are in contact. The open / close detection means 19 is configured as a reed switch, and the control means 6 detects the open / closed state of the lid 8 based on information from the open / close detection means 19.
[0021]
In this figure, connections such as power lines and signal lines are omitted. In this cooked rice warmer, after cooking, the temperature of the cooked rice is detected by the temperature detecting means 4 in contact with the bottom of the inner pot 1. This information is sent to the control means 6, and the heating means 5 is supplied with electric power to generate a magnetic force so that the temperature of the cooked rice becomes 72 ° C., which is the heat retention set temperature, and is composed of a clad material made of stainless steel and aluminum. The stainless steel layer of the inner pot 1 is heated by electromagnetic induction to keep the cooked rice warm.
[0022]
In addition, the control means 6 electronically controls the input of the heating means 7 and 10, thereby giving a heating heat amount corresponding to the amount of cooked rice and keeping the cooked rice temperature at the heat retention set temperature 72 ° C.
[0023]
Further, the control means 6 controls the nitrogen supply means 15, the valve 18 and the gas transport means 16 a and 16 b, and continuously supplies nitrogen-rich gas, or intermittent supply in which the supply is repeated at regular intervals. Even if the lid 8 is sealed for a long time, it is possible to provide delicious cooked rice by scattering the warming odor, suppressing yellowing of the cooked rice and deterioration of physical properties during eating. That is, during rice cooking, the valve 18 isolates the nitrogen supply means 15 and the inner pot 1.
[0024]
Further, during rice cooking, the nitrogen supply means 15 and the nitrogen storage means 17 are electrically connected by the valve 18, and after the completion of rice cooking, the nitrogen storage means 17 and the inner pot 1 are electrically connected by the valve 18. Further, when the opening / closing detection means 19 detects that the lid 8 is opened, the nitrogen supply means 15 and the nitrogen storage means 17 are electrically connected by the valve 18, and the opening / closing detection means 19 indicates that the lid 8 is closed. When detected, the nitrogen storage means 17 and the inner pot 1 are electrically connected by the valve 18.
[0025]
During these operations, the gas transport means 16a and 16b are appropriately controlled.
[0026]
Next, the nitrogen supply means 15 is demonstrated based on FIG. This includes a solid electrolyte 20 having oxygen ion conductivity, a pair of electrodes 21 and 22 formed on different surfaces of the solid electrolyte 20, and a voltage supply device 23 connected between the pair of electrodes 21 and 22. A heater 24 for heating the solid electrolyte 20, a heater power supply 25 for supplying a voltage to the heater 24, and a heat insulating material 26 provided around the solid electrolyte 20 and the heater 24, Oxygen contained in the air is removed and discharged to the outside, and the remaining nitrogen-enriched gas is supplied to the inner pot 1. The solid electrolyte 20 and the pair of electrodes 21 and 22 constitute an oxygen pump. The voltage-current characteristics of this oxygen pump are shown in FIG.
[0027]
The heat insulating material 26 is provided to efficiently heat the solid electrolyte 20 with the heater 24, and the heater 24 is embedded in the heat insulating material 26 and formed integrally to reduce the size of the nitrogen supply means 15. It's striking.
[0028]
Further, since the heat insulating material 26 is porous and has air permeability, the gas can flow in and out sufficiently, and oxygen can be exchanged between the outside and the pair of electrodes 21 and 22 without delay, and the nitrogen-rich material can be efficiently enriched. Gas can be supplied.
[0029]
In addition, a sealing material 27 is provided for airtightly separating different spaces in which the pair of electrodes 21 and 22 are formed, and the solid electrolyte 20 is airtightly fixed to the heat insulating material 26 and a metal housing, The nitrogen-enriched air separated at the electrode 21 (cathode) and the oxygen released from the other electrode 22 (anode) are separated without mixing, and an efficient nitrogen-enriched gas can be supplied. I can do it.
[0030]
As the solid electrolyte 20, a disk made of lanthanum gallium oxide having oxygen ion conductivity and having a diameter of about 20 mm and a thickness of 1 mm was used. A paste made of perovskite oxide was printed on both sides as a pair of electrodes 21 and 22 and dried. Further, a current collector was laminated thereon, and a sealing material 27 made of metal foil and lead wires were attached and fired in an electric furnace. The solid electrolyte 20 can also use other stabilized zirconia having stabilized oxygen ion conductivity, stabilized ceria, and the like. In order to improve the oxygen ion conductivity of the lanthanum gallium oxide used in the examples, A part of the gallium site may be substituted with a different metal such as a transition metal or an alkaline earth metal.
[0031]
Further, a current detection means 28 for detecting a current flowing through the solid electrolyte 20 is connected between the voltage supply device 23 and the solid electrolyte 20. When the solid electrolyte 20, the pair of electrodes 21, 22 or the heater 24 deteriorates due to a drop or deterioration of durability, a change appears in the current flowing through the solid electrolyte 20. Therefore, based on the detection value of the current detection means 28. When the control means 6 self-diagnose the state of the nitrogen supply means 15 and the detection value of the current detection means 28 exceeds a preset threshold value, it determines a period during which delicious cooked rice can be provided and replaces the nitrogen supply means 15. You can prompt or let you know the life.
[0032]
The atmosphere taken in from the outside and supplied to the nitrogen supply means 15 reaches one electrode 21 (cathode) via the porous heat insulating material 26, and oxygen contained in the atmosphere is adsorbed on the cathode 21. When a voltage is applied between the pair of electrodes 21 and 22 by the voltage supply device 23, the adsorbed oxygen receives electrons and is solid from a three-phase interface formed between the electrode 21, the solid electrolyte 20, and the gas phase. It is taken into the electrolyte 20 and becomes oxygen ions and moves through the solid electrolyte 20. Oxygen ions that have reached the other electrode 22 (anode) emit electrons at the three-phase interface formed between the electrode 22, the solid electrolyte 20, and the gas phase, become oxygen again, and are discharged to the atmosphere.
[0033]
The nitrogen-enriched gas from which oxygen has been removed is supplied to the inner pot 1 by the operation of the gas transport means 16a or 16b, and is replaced with a gas containing high-concentration oxygen, and the gas containing high-concentration oxygen is discharged to the outside. And discharged. As a result, the inner pot 1 has a low oxygen concentration, and it is suppressed that lipids, proteins and carbohydrates in the cooked rice are oxidized with oxygen in the air, and these substances are not decomposed or polymerized. The occurrence of yellowing and warming odor can be reduced. Moreover, the activity of bacteria can be suppressed and the decay of cooked rice can be delayed.
[0034]
Using the cooked rice warmer configured as described above, the heat insulation state of cooked rice was examined. First, rice and water, which are raw materials for cooked rice, were put into the inner pot 1 and cooked. In addition, while cooking rice at the same time, the heater 24 of the nitrogen supply means 15 is supplied with power of 10 to 20 W using the heater power supply 25, and the operating temperature of the oxygen pump composed of the solid electrolyte 20 and the pair of electrodes 21 and 22 is achieved. Was heated to 600 to 700 ° C.
[0035]
Then, a predetermined voltage was supplied between the pair of electrodes 21 and 22 by the voltage supply device 23, and the gas transport means 16 b was operated to take in nitrogen-rich gas into the nitrogen storage means 17. The nitrogen supply amount can be changed by controlling the voltage supply device 23 and the gas transport means 16b. The oxygen concentration in the nitrogen storage means 17 immediately after cooking rice was about 2%.
[0036]
Moreover, although the oxygen concentration of the gas in the inner pot 1 immediately after cooking rice was almost 0%, the inside cooled and the saturated vapor pressure decreased, and air flowed in from the outside, and the oxygen concentration gradually increased.
[0037]
Therefore, the control means 6 operates the valve 18 and the gas transport means 16a that have isolated the inner pot 1 to supply a nitrogen-enriched gas having a sufficiently low oxygen concentration stored in the nitrogen storage means 17 in the inner pot 1. Introduced promptly.
[0038]
FIG. 4 shows the relationship between the heat retention time and the oxygen concentration in the inner pot 1 when the air in the inner pot 1 is replaced with nitrogen-enriched gas in the nitrogen supply means 15 and the nitrogen storage means 17. The oxygen separated by the oxygen pump is discharged to the outside at 10 to 30 cc per minute, and the separated nitrogen is again mixed with air to become a nitrogen-enriched gas, and continuously the nitrogen storage means 17 at 40 to 120 cc per minute. Supplied to When the nitrogen storage means 17 and the inner pot 1 are connected by the valve 18, the air in the inner pot 1 is quickly replaced with a nitrogen-enriched gas, and the oxygen concentration in the inner pot 1 is 2 to 4% in 20 to 60 minutes. Therefore, the nitrogen supply amount was reduced and kept as it was. The oxygen concentration in the inner pot 1 increased due to the inflow of external air after a while, but the oxygen concentration in the inner pot 1 can be quickly reduced by increasing the nitrogen supply amount again at a low concentration stage to some extent. I was able to.
[0039]
Further, at this time, it was found that the inside of the inner pot 1 is almost at atmospheric pressure, and the airtight structure is simple.
[0040]
Next, immediately after cooking, sensory evaluation was performed when the oxygen concentration in the inner pot 1 was maintained at 2 to 4%. When kept in the atmosphere, the rice was slightly oxidized and the evaluation of the warm odor and taste was low, whereas when kept at a low oxygen concentration, the warm odor was small and the taste was good.
[0041]
Furthermore, when the sensory evaluation of the cooked rice that had been kept warm for 12 hours and 24 hours in this state, both had a little warming odor, had a freshly cooked odor, little yellowing, sticky taste evaluation, and elasticity The overall evaluation was high. On the other hand, the cooked rice that had been kept warm for 12 hours and 24 hours in the atmosphere had a warm odor, yellowing, poor taste, and low overall evaluation.
[0042]
Next, the heat insulation state of the cooked rice when the lid 8 was opened and closed was examined. While the lid 8 is closed, the nitrogen supply means 15 supplies nitrogen-rich gas to the nitrogen storage means 17, and immediately after the lid 8 is opened, the oxygen concentration in the inner pot 1 is the oxygen concentration in the atmosphere. It became equal to 20.8%. When the lid 8 was closed, the open / close detection means 19 detected that the lid 8 was closed, and the valve 18 and the gas transport means 16a were operated.
[0043]
The air in the inner pot 1 is immediately replaced with a nitrogen-enriched gas having a sufficiently low oxygen concentration stored in the nitrogen storage means 17, and the oxygen concentration in the inner pot 1 is 2 to 4% in 20 to 60 minutes. Therefore, the nitrogen supply amount was reduced and kept as it was. The oxygen concentration in the inner pot 1 increased due to the inflow of external air after a while, but the oxygen concentration in the inner pot 1 can be quickly reduced by increasing the nitrogen supply amount again at a low concentration stage to some extent. I was able to.
[0044]
The sensory evaluation of the cooked rice when the lid 8 was opened and closed also showed comprehensively good results such as a warm odor, yellowing of cooked rice, and physical properties of the taste.
[0045]
Moreover, it turned out that delicious cooked rice with little heat retention odor can be provided by changing supply_amount | feed_rate of nitrogen-enriched gas according to the quantity of cooked rice to heat retention.
[0046]
【The invention's effect】
As described above, according to the cooked rice incubator of the present invention, nitrogen supply means for removing oxygen contained in the atmosphere and supplying nitrogen-rich gas, nitrogen storage means for storing nitrogen-rich gas, Control means for controlling the supply amount of nitrogen, and the control means controls the supply amount of nitrogen-rich gas from the nitrogen storage means to the inner pot. The unpleasant warming odor generated in the kettle can be scattered to prevent yellowing of the cooked rice and physical properties from being deteriorated during eating, and a delicious cooked rice can be provided even if kept warm.
[Brief description of the drawings]
1 is a cross-sectional view showing a schematic configuration of a rice cooker according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a nitrogen supply unit of the rice cooker. FIG. 3 is a voltage-current characteristic diagram of the nitrogen supply unit. [Chart 4] Characteristic diagram showing the relationship between the heat retention time and oxygen concentration of the rice cooker
DESCRIPTION OF SYMBOLS 1 Inner pot 4,11 Temperature detection means 5, 7, 10 Heating means 6 Control means 8 Cover 15 Nitrogen supply means 16a, 16b Gas transport means 17 Nitrogen storage means 18 Valve 19 Opening / closing detection means 20 Solid electrolyte 21, 22 Pair of electrodes 23 Voltage supply device 24 Heater 25 Heater power supply 26 Heat insulation material 27 Seal material 28 Current detection means

Claims (2)

An inner pot for storing cooked rice, an openable / closable lid provided above the inner pot, heating means for heating the cooked rice in the inner pot, temperature detecting means for detecting the temperature of the inner pot, and in the atmosphere Nitrogen supply means for removing contained oxygen and supplying nitrogen-enriched gas to the inner kettle, gas transport means for transporting nitrogen-enriched gas, and nitrogen for storing nitrogen-enriched gas from said nitrogen supply means Based on the detected value of the storage means and the temperature detection means, the heating means is used to heat the cooked rice to a predetermined temperature, and the supply amount of nitrogen-enriched gas from the nitrogen storage means to the inner pot is controlled. A rice cooker comprising control means for controlling.   A valve is provided between the nitrogen supply means, the inner pot, and the nitrogen storage means. During rice cooking, the nitrogen supply means and the nitrogen storage means are conducted with the valve, and after the completion of rice cooking, the nitrogen storage means and the inner kettle are conducted with the valve. The cooked rice warmer according to claim 1.

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