JP3473461B2 - Rice cooker - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cooked rice warmer.

[0002]

2. Description of the Related Art Generally, when rice is heated to a higher temperature,
Yellowing of cooked rice, generation of heat retention odor, and deterioration of taste physical properties occur.
In addition, when the heat retention temperature becomes low, the rice is spoiled by bacteria. Various techniques have been developed to solve these problems.

As an example, a conventional rice warmer the operation and construction of the (rice cookers), will be described with reference to FIG.

In FIG. 4 , reference numeral 1 denotes an inner pot for heating and cooking by adding a predetermined amount of rice and water. A pot temperature detector 4 is provided on the bottom of the inner frame 3 of the main body 2 so as to contact the bottom of the inner pot 1. Further, a heating coil 5 for electromagnetic induction is provided on the bottom of the inner frame 3.
And 6 is a control unit. The control unit 6 also has a high frequency power supply that supplies power to the heating coil. Further, a heat insulation heater 7 is provided above the inner frame 3. A lid 8 that can be opened and closed is provided on the upper portion of the main body 1, and a radiator plate 9, a lid heater 10, and a lid temperature detector 11 are provided on the inner surface of the lid 8. An operation panel unit 14 is provided on the upper portion of the main body 2.

In conventional rice cookers such as jar rice cookers,
The temperature of the cooked rice being kept warm is detected by a pot temperature detector 4 in contact with the bottom of the inner pot 1. This information is sent to the control unit 6 and electric power is supplied to the heating coil so that the temperature is set to a predetermined heat retention temperature, for example, 72 ° C., and the stainless steel layer of the clad material of the inner pan 1 and the aluminum is electromagnetically induced. To heat. In addition, the control unit 6 electronically controls the inputs of the warming heater 7 and the lid heater 10 to give a heating heat amount according to the amount of cooked rice and keep the cooked rice temperature at the preset warming temperature 72 ° C.

However, in the conventional cooked rice warmer, since the cooked rice is kept at a constant temperature of about 72 ° C. when it is kept warm, there is a warm feeling when eating, but when it is kept warm for a long time, the cooked rice reacts with oxygen in the air. It deteriorates and emits yellow (brown) color and unique heat retention odor. Further, there is a problem that the taste and physical properties such as elasticity are deteriorated.

As one of the methods for solving the above-mentioned problems, Japanese Patent Laid-Open No. 5-154039 discloses a decompression device for decompressing the air in an inner pot and a gas separation device for allowing only oxygen in the air to pass through before the decompression device. The technology of a warmer equipped with a membrane is disclosed. This technique discharges the air in the inner pot to the outside of the main pot to reduce the absolute amount of oxygen in the inner pot, or reduces the pressure using a gas separation membrane that allows only oxygen to pass through the inner pot. It is intended to reduce the absolute amount of oxygen while discharging only the oxygen to reduce the oxygen concentration, and to prevent the occurrence of yellowing and odor of cooked rice.

However, this method has a structure in which the air in the inner pot is discharged by a decompression device, and since a high degree of airtightness inside the inner pot is required, the structure is complicated and the high degree of airtightness is maintained for a long time. Is difficult. Moreover, since it is a kind of pressure vessel, it is difficult to configure it for home use. For this reason, if the temperature is kept for several hours, the hermeticity is impaired, air flows in, the oxygen concentration in the inner pot rises, and there is a problem that the cooked rice deteriorates due to the heat retention .

[0009]

In the above conventional technique, an oxidation reaction of lipids, proteins and carbohydrates in cooked rice with oxygen in the air, or a decomposition reaction and a polymerization reaction of these substances occur during heat retention, There is a problem of yellowing of cooked rice, heat retention odor, and deterioration of taste and physical properties.Therefore, in order to reduce the oxygen concentration in the inner pot, the air pressure in the inner pot is maintained by the decompression device to maintain the airtight state. Therefore, there is a problem that a highly airtight structure is required.

Further, in the structure in which the air in the inner pot is discharged through the oxygen separation membrane, there is a problem that dew condensation water accumulates at the time of discharging the air, and it decomposes or flows into the inner pot.

[0011]

In order to solve the above-mentioned problems, the present invention according to claim 1 is an inner pot for containing cooked rice,
An openable and closable lid placed above the inner pot, heating means for heating the cooked rice in the inner pot, inner pot temperature detecting means for sensing the temperature of the inner pot, control means, and pressure feeding. With a wind device
Sending air to the gas separation membrane to control the flow rate of gas with low oxygen concentration
For the rice warmer configured to blow air into the inner pot through the device
The control means detects the inner pot temperature detection means.
Based on the value, the cooked rice is controlled to a predetermined temperature by using the heating means.
Gyoshi, wherein controlling the pressurized pumping air device and the flow control device further
When sending a large flow of air that is lower than air but has a high oxygen concentration
Control when sending a small flow rate of air with a lower oxygen concentration
It is characterized by configuring a cooked rice warmer .

[0012] In addition, from rice and water, which are raw materials of the cooked rice,
It has a rice cooking function to create the cooked rice, and after the cooked rice is created
Controls the pressurized air blower and flow rate controller after a lapse of a fixed time
When the flow rate of air with a high oxygen concentration, which is lower than that of air, is high
After a short period of time, send a small amount of air with a lower oxygen concentration
It is characterized in that the cooked rice warmer according to claim 1 is controlled .

Further , a lid opening / closing detection mechanism is provided,
With the rice cooked at the specified temperature, open the lid
After detecting that it is closed with the opening and closing detection mechanism,
Controls the pressure blower and the flow controller,
After sending a large amount of air with a high oxygen concentration for a certain period of time,
A control for controlling a small flow rate of air having a lower degree.
The cooked rice warmer described above is configured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The means according to claim 1 is used in the air.
Oxygen is removed by a gas separation membrane, and oxygen lower than in air
By feeding high-concentration air into the pan with a large flow rate,
The oxygen concentration in the inner pan is quickly lowered to a somewhat low level.
To send a small flow of air with a lower oxygen concentration.
By lowering the concentration to a lower level, the oxidation reaction and the decomposition polymerization reaction during heat retention are suppressed, the heat retention odor and yellowing of cooked rice during heat retention are prevented, and the taste of cooked rice is prevented from deteriorating.

The means according to claim 2 is an inner pot after cooking rice.
High temperature steam inside is removed by oxygen in air by gas separation membrane
However, air with a high flow rate, which is lower than that in the air, but with a high oxygen concentration
The oxygen concentration in the inner pan is rapidly increased by feeding it inside.
Lowers the cooked rice temperature to a low level
Then send a small flow of air with a lower oxygen concentration.
By lowering the oxygen concentration to a lower level,
If the amount of air enriched with nitrogen is too large, the water on the surface of the cooked rice will evaporate more and the problems such as yellowing due to drying and hardening of the surface will be solved, and the warm odor and yellowing of cooked rice will be prevented and the taste will deteriorate. The purpose is to prevent.

According to the third aspect of the present invention, since the oxygen concentration rises to the same level as in the air by opening and closing the lid, the opening / closing detection mechanism indicates that the lid is opened to closed.
After detecting with, control the pressure blower and flow controller
When the flow rate of air with a high oxygen concentration, which is lower than that of air, is high
The oxygen concentration is rapidly reduced by feeding
By sending a small flow rate of low air to the inside, the oxygen concentration in the inner pot is reduced, oxidation and decomposition polymerization reaction during heat retention are suppressed, the heat retention odor of cooked rice and yellowing are prevented, and the taste of cooked rice is reduced. The purpose is to prevent.

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic view of a jar rice cooker incorporating a cooked rice warmer according to an embodiment of the present invention. In FIG. 1, 1
Is an inner pot, in which a certain amount of rice and water are put and cooked. A pot temperature detector 4 is provided on the bottom of the inner frame 3 of the main body 2 so as to contact the bottom of the inner pot 1. In addition, there is an electromagnetic induction heating coil 5 on the bottom of the inner frame 3. Reference numeral 6 denotes a control unit, which also includes a high frequency power supply that supplies electric power to the heating coil. Also,
On the upper part of the inner frame 3 is a heat retaining heater 7. A lid heater 10 and a lid temperature detector 11 are provided on the heat dissipation plate 9 below the lid portion 8 .

In this jar rice cooker, the temperature of the cooked rice is maintained by the pan temperature detector 4 in contact with the bottom of the inner pan 1. This information is sent to the control unit 6, and electric power is supplied to the heating coil so that the temperature of the cooked rice becomes 72 ° C which is the heat retention setting temperature to generate magnetic force, and the inner pot made of the clad material of stainless steel 51 and aluminum 52 is used. The stainless steel layer 1 is heated by electromagnetic induction to keep the cooked rice warm. In addition, the control unit 6 electronically controls the inputs of the warming heater 7 and the lid heater 10 to give a heating heat amount according to the amount of cooked rice, and to set the warming preset temperature 7
It has to keep the cooked rice temperature to 2 ° C..

Further, pressurized air in the pressurized pumping air device 18 is sent to the gas separation membrane 15, where the oxygen is removed, nitrogen and nitrogen-enriched air enriched, the inner bowl 1 through the air blowing port 13 It is configured to flow inside. The material and cross-sectional area of the gas separation membrane will be described later. Further, a flow rate control device 16 is provided between the gas separation membrane 15 and the blower port 13 so that the amount of air flowing into the inner pot 1 can be controlled by the control unit 6. Reference numeral 21 is an air outlet, which also functions as a steam vent when cooking rice. Further, a lid opening / closing detector 17 is provided at a place where the main body 2 and the lid portion 8 are in contact with each other. This lid opening / closing detector 17
It is configured like a reed switch, and the control unit 6 detects the open / closed state of the lid based on the information from the lid open / close detector 17.

The gas separation membrane 15 used here has an area of 2
It is 800 cm 2 and is made of silicon resin. Oxygen is easily dissolved in this. Alternatively, a polyimide resin or a 4-methylpentene resin may be used. The shape is a 5 cm diameter × 200 cm long tube wound spirally,
By covering the outside, oxygen-enriched air is released to the outside, and nitrogen-enriched air can be introduced into the cooked rice warmer. In addition to this, gauge pressure 1 kgf / cm2 (1
When pressurized air is sent to (MPa), oxygen permeates through the gas separation membrane 15 and nitrogen remains in the remaining air as a result, thereby supplying nitrogen-enriched air. You can Since the amount of oxygen passing through the gas separation membrane 15 is determined to some extent, the remaining oxygen concentration increases when the air supply amount is large, and the remaining oxygen concentration decreases when the air supply amount is small. FIG. 2 is a diagram showing the performance of the gas separation membrane 15, in which the amount of gas at the outlet is 200 cc / mi.
When n, the oxygen concentration is 4% and the amount of gas at the outlet is 50 cc / mi
When n, the oxygen concentration is 0.5%.

The operation of the jar rice cooker configured as described above will be described below. First , as ( Example 1 ), the flow rate control device 16 is operated and the lid opening / closing detector 17 is operated.
Is the case of not operating. Not operating does not have to be. In FIG. 2, the amount of air flowing out from the blower port 13 can be changed by controlling the flow rate control device 16. In this embodiment, after the rice is cooked, for example, when the oxygen concentration in the inner pot 1 rises, for example, one hour has passed, the flow rate of the nitrogen-enriched air flowing into the inner pot 1 is set to 200 cc / min and is flowed for about 20 minutes. Then, the oxygen concentration inside the inner pot 1 drops to about 6%. afterwards,
When the flow rate is set to 50 cc / min, the oxygen concentration in the inner pot 1 drops to 2%. If the flow rate is kept at 50 cc / min as it is, the oxygen concentration in the inner pot 1 is kept at 2%.

In this way, even if the oxygen concentration is somewhat high, a large amount of air is made to flow into the inner pot 1 to rapidly reduce the oxygen concentration, and when the air in the inner pot 1 becomes a low concentration to some extent. By sending air having a low oxygen concentration, the oxygen concentration in the inner pot 1 can be rapidly lowered.

As this example and (Comparative Example 1 ), 50
When the temperature is kept at a constant flow rate of cc / min for 12 hours and 2
Table 1 shows a comparison with the case where the temperature is kept for 12 hours at a constant flow rate of 00 cc / min.

As can be seen from this table, 200 immediately after cooking rice.
When it is flowed at cc / min for 20 minutes and then changed to 50 cc / min, the heat-retaining odor is small and the taste is good. 50 cc / m
In the case of in, it takes time to replace the oxygen in the inner pot and a little oxidation of the cooked rice occurs, so there is an effect of improving both the heat retention odor and the taste, but it is inferior to the examples. At a flow rate of 200 cc / min, the surface of cooked rice dries and the taste becomes hard, which is not preferable.
The conventional example has no effect of improving heat retention.

[0025]

[Table 1]

Next, as a second embodiment, the flow control device 16 is operated and the lid opening / closing detector 17 is also operated.

After the lid 8 is opened, the oxygen concentration in the inner pot 1 becomes equal to the oxygen concentration in the air, which is 20.8%.
Therefore, in the present embodiment, after the lid open / close detector 17 detects that the lid is closed, the flow rate of the nitrogen-enriched air flowing into the inner pot 1 is set to 200 cc / min immediately after the lid is closed.
And run for about 20 minutes. At this time, the oxygen concentration of the inflowing nitrogen-enriched air is 4%. Then, the oxygen concentration inside the inner pot 1 drops to about 6%.

Thereafter, the flow rate of the nitrogen-enriched air is changed to 50 cc /
It is set to min, and the concentration of oxygen flowing in is further reduced to 0.5%. Then, the oxygen concentration in the inner pot 1 drops to 2%.

FIG. 3 is a diagram showing the relationship between the nitrogen-enriched air inflow rate of this jar rice cooker and the oxygen concentration in the inner pot 1. When the lid is opened, the oxygen concentration is almost the same as the atmosphere.
Therefore, as shown in FIG. 3 , the flow rate of the nitrogen-enriched air flowing into the inner pot 1 is 200 cc / min immediately after the lid is closed.
For about 20 minutes. Then, the oxygen concentration inside the inner pot 1 drops to about 6%. After that, change the flow rate to 50 cc / min
Then, the oxygen concentration in the inner pot 1 drops to 2%. If the flow rate is kept at 50 cc / min as it is, the oxygen concentration in the inner pot 1 is kept at 2%.

As described above, when the lid is opened and the oxygen concentration becomes almost the same as the atmosphere, immediately after the lid is closed, a large amount of air is flown into the inner pot 1 even if the oxygen concentration is somewhat high, and the oxygen concentration is rapidly increased. When the air in the inner pot 1 is reduced to a certain extent and air with a low oxygen concentration is sent to the inner pot 1, the oxygen concentration in the inner pot 1 can be rapidly reduced.

This is because if an oxygen concentration of 0.5% is to be obtained at 200 cc / min, the area of the oxygen-enriched film is required to be about 4 times, so that the equipment can be made compact and the cost can be reduced. Therefore, the capacity is changed stepwise in this way, and it is possible to effectively obtain low-concentration oxygen with one module.

When the flow rate is changed by opening and closing the lid,
(Comparative example 2 ) 1 at a constant flow rate of 50 cc / min
Table 2 shows the evaluation results of cooked rice when kept warm for 2 hours.

As shown in this table, the flow rate of 200 cc / min immediately after opening and closing of the lid and then 50 cc / min of flow has a great effect of improving the thermal odor and taste. 5
With a constant flow rate of 0 cc / min, when the lid was opened and closed frequently, oxygen was introduced each time and the oxygen concentration temporarily increased, so oxidation proceeded, and the heat retention improving effect was smaller than that of (Example 2 ). Become.

[0034]

[Table 2]

In this embodiment, since the remaining air that has passed through the oxygen separation membrane is sent in, dew condensation does not occur on the oxygen separation membrane and the oxygen separation capacity does not deteriorate. Furthermore, since the nitrogen-enriched air inflow path is also dry, dew condensation water does not accumulate and decompose or flow into the inner pot. Since the nitrogen-enriched air is sent in, the inner pot is at almost normal pressure (atmospheric pressure), and the airtight structure is simple.

[0036]

The present invention as described above, according to the present invention reduces the oxygen concentration in the inner pot by feeding the inner kiln air nitride Mototomi reduction suppresses oxidation and decomposition polymerization reaction of cooked rice in warmth , It prevents yellowing and heat odor of cooked rice while it is kept warm, and provides more delicious cooked rice even when kept warm. Since the remaining air that has passed through the oxygen separation membrane is sent in, dew condensation does not occur on the oxygen separation membrane and the oxygen separation ability does not decrease. Furthermore, since the nitrogen-enriched air inflow path is also dry, dew condensation water does not accumulate and decompose or flow into the inner pot. Since the nitrogen-enriched air is sent in, the inner pot is at almost normal pressure (atmospheric pressure), and the airtight structure is simple.

In addition, according to the present invention, after cooking rice, a large amount of nitrogen-enriched air is first fed into the inner pot, and then a proper amount of nitrogen-enriched air is fed into the inner pot to quickly reduce the oxygen concentration in the inner pot. It prevents yellowing and heat retention odor, and also prevents the cooked rice from drying due to blowing air, and provides even more delicious cooked rice even when kept warm.

Further, according to the present invention, after keeping the lid open and closed while keeping warm, a large amount of nitrogen-enriched air is first sent into the inner pot to make the oxygen concentration in the inner pot low quickly. It prevents yellowing and heat odor of cooked rice while it is kept warm, and also prevents the cooked rice from drying due to blowing air, and provides more delicious cooked rice even when kept warm.

[Brief description of drawings]

FIG. 1 is a schematic view of a jar rice cooker incorporating a cooked rice warmer according to an embodiment of the present invention.

[Fig. 2] Outlet air of the gas separation membrane used in the rice cooker
Diagram showing the relationship between amount and oxygen concentration

[Figure 3] Nitrogen-enriched air inflow rate and inner pot of the rice cooker
Diagram showing the relationship with the oxygen concentration in the water

FIG. 4 is a sectional view of a conventional jar rice cooker.

[Explanation of symbols]

1 inner pot 4 Pan temperature detector 5 heating coils 6 control unit 12 Blower 13 Blower 15 Gas separation membrane 16 Flow control device 17 Lid open / close detector 18 Pressure blower

Continuation of the front page (56) Reference JP-A-5-192244 (JP, A) JP-A-5-154039 (JP, A) JP-A-6-14023 (JP, A) JP-A-63-135108 (JP , A) Jitsuhei 8-4898 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) A47J 27/00 103

Claims (3)

(57) [Claims] 1. An inner pot for containing cooked rice, an openable lid placed above the inner pot, heating means for heating the cooked rice in the inner pot, and a temperature of the inner pot. The inner pan temperature detection means, the control means, and the air blower for the gas separation membrane by the pressure blower.
The gas with low oxygen concentration through the flow controller
In the cooked rice warmer configured to blow air into the inner pot, the above control
The means is the heating based on the detection value of the inner pot temperature detection means.
Means to control the cooked rice to a predetermined temperature, and
Controls the pressure blower and the flow controller,
When sending a large flow rate of air with high oxygen concentration,
A rice cooker characterized by controlling the case of sending a small amount of low air . 2. The rice from the rice and water which are the raw materials of the cooked rice
It has a rice cooking function to make rice, and it takes a certain time after the rice is made.
After the lapse of time, the pressure blower and the flow rate controller are controlled to control the air.
Air with a lower oxygen concentration but a higher oxygen concentration
After that, control to send a small flow rate of air with a lower oxygen concentration.
The cooked rice warmer according to claim 1, wherein the cooked rice warmer is controlled. 3. A lid opening / closing detection mechanism is provided, and after the lid opening / closing detection is detected by the opening / closing detection mechanism while the cooked rice is at the predetermined temperature , the pressure feeding is performed.
It controls the air blower and the flow controller to control the oxygen concentration lower than in the air.
After sending a high flow rate of air at a high flow rate for a certain period of time, the oxygen concentration
Characterized by controlling so that low air is sent at a low flow rate
The rice cooker according to claim 1 .