JP3291973B2 - Method of controlling heat retention of electronic rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of heat retention of an electronic rice cooker mainly used at home.

[0002]

2. Description of the Related Art In recent years, it has been required to improve the heat insulation performance by suppressing changes in viscoelasticity, color, and odor so that not only freshly cooked rice but also heated rice can be eaten deliciously. ing. In the current electronic jar rice cooker, the heat retention temperature is set at a temperature of 71 ± 6 ° C. specified in JIS C9212 (1976). It is generally known that in order to further improve the heat retaining performance, it is sufficient to keep the temperature at about 60 ° C. However, since rice is easily spoiled, various means for preventing spoilage have been devised.

Conventionally, the heat retention control for preventing this kind of putrefaction has been configured as shown in Japanese Patent Publication No. 63-40411. Hereinafter, the configuration will be described with reference to FIG.

As shown in FIG. 5, spoilage bacteria (Bacillus sta
gerothermlulus) at a temperature level of 1 (60 ° C.) at which the growth temperature can be maintained for 3 hours, and at a temperature level at which the spoilage bacterial vegetative cells can be killed at 3 (75 ° C. or higher), the kill temperature is only 4 hours. Control is performed to prevent decay by repeatedly keeping the temperature in a high temperature range.

In the above configuration, when the heat retention control is performed,
In the growth temperature holding time 3, when the putrefactive bacterium repeats two divisions and exceeds about 400 minutes, humans will perceive the odor of putrefaction, but the rice is heated at the temperature level 3 (75 ° C. or more) for the killing temperature holding time 4 By doing so, putrefactive bacterial vegetative cells are killed and putrefaction odor can be prevented.

[0006]

In such a conventional heat retention control, it may be difficult to determine the amount of rice at the time of heat retention, and the electric power of the heater is constant regardless of the amount of rice. Depending on the amount, the rice may be yellowed or dried due to excessive heating, or the rice may easily rot due to insufficient heating.

[0007] The present invention has been made to solve the above problems, and has as its first object to improve the taste of rice kept warm.

[0008] A second object is to appropriately improve the taste according to the amount of rice kept warm by a simple control method.

A third object is to improve the taste more appropriately in accordance with the amount of rice kept warm.

It is a fourth object of the present invention to prevent the rice kept warm from drying or spoiling when the amount of rice is large.

[0011]

In order to achieve the first object, the present invention provides an inner pot for putting rice, a heater for heating the inner pot, and a temperature detector for detecting the temperature of the inner pot. Means, heating control means for cooking and maintaining the temperature by controlling the heater using the output of the temperature detection means as input, and rice cook amount determination means for determining the amount of rice put in the inner pot during cooking. And the electric power of the heater is changed by the heating control means at the time of keeping the temperature in accordance with the rice cooked amount determined during the rice cooking by the rice cooked amount determining means.

In order to achieve the second object,
According to the present invention, in particular, the heating control means includes a first heat retention control temperature point and a second heat retention control temperature point higher than the first heat retention control temperature point.
The control is performed such that the temperature of the rice is alternately maintained at the two temperature control temperature points.

In order to achieve the third object, the present invention maintains the temperature of the rice at the second temperature control temperature point, particularly according to the amount of cooked rice determined by the cooked rice amount determining means during cooking. The length of time is changed.

Further, if the rice cooked amount determined by the rice cooked amount determination means is equal to or more than the predetermined rice cooked amount, the heat retention control is performed at one temperature control temperature point, and if the rice cooked amount is less than the predetermined rice cooked amount, two heat control is performed. The fourth object is achieved by performing the heat retention control at the above-mentioned heat retention control temperature point.

[0015]

According to the present invention, by using the amount of cooked rice determined during cooking, the present invention can perform appropriate heating according to the amount of rice even when the temperature is kept warm, and keep the rice warm state well. Is what you can do.

Further, by changing the electric power of the heater for heating the rice from the first temperature control temperature point to the second temperature control temperature point in accordance with the amount of the rice, a simple method can be used. It is possible to appropriately secure the time for maintaining the temperature of the rice at the temperature control point 2 of the temperature control, and to control the temperature of the rice to alternately maintain the temperature of the rice at the two temperature control temperature points. Also, the rice can be kept in a good heat-retaining state.

[0017] Further, by changing the length of time during which the temperature of the rice is maintained at the second temperature control temperature point in accordance with the amount of cooked rice determined during the cooking of the rice, it is possible to further maintain the state of keeping the rice warm. You can do it.

If the amount of cooked rice determined during cooking is equal to or greater than a predetermined amount of cooked rice, the heat control is performed at one heat control temperature point, so that the rice is dried during the heat retention even if the amount of rice is large. It can effectively prevent dripping and decay.

[0019]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, an inner pot 5 for placing rice is placed on a heater 6 and heated. At the bottom center of the inner pan 5, a temperature detecting means 7 is provided so as to be in contact with the inner pan 5, and a signal is sent to the heating control means 8, and the heating control means 8 controls the heater 6 based on the signal. ing. A lid 9 is provided above the inner pan 5 so as to be freely opened and closed. The lid 9 is provided with a lid temperature sensor 10 for detecting an ambient temperature inside the inner pan 5. The signal from the lid temperature sensor 10 is also sent to the heating control means 8 and used for controlling the heater 6.

The operation of the above configuration will be described.
When rice and water are put into inner pot 5 and rice cooking is started, heater 6
The rice and water are heated by the
The time from when 80 ° C. is detected to when the lid temperature sensor 10 detects 90 ° C. is measured by the heating control means 8, and the amount of cooked rice can be determined based on the length of this time.
Based on the determined amount of cooked rice, the heating control means 8 controls the heater 6 to perform optimal heating, and ends the cooked rice. After cooking, keep warm. The operation of the heat retention control at this time will be described with reference to FIG. In FIG. 2, the vertical axis indicates the temperature level of rice and the horizontal axis indicates time. After the rice cooking, the rice is cooled naturally, and the temperature is detected by the temperature detecting means 7 so that the temperature of the rice is maintained at the temperature level 2 (71 ° C.) of the normal temperature keeping after the elapse of the cooling time 12, and the heating control means 8 controls the heater 6. Specifically, heating is performed by the heater 6 for the heating time 13 and heating by the heater is suspended for the heating suspension time 14 to maintain the temperature of the rice at the temperature level 2 (71 ° C.) for normal heat retention. At this time, the power of the heater 6 is changed by changing the duty ratio of the heater 6 according to the amount of cooked rice determined during cooking. That is, if the amount of rice is large, the amount of electric power of the heater 6 is increased,
If the amount of rice is small, reduce the amount of electricity. By changing the amount of power of the heater 6, when the amount of rice is small, it is possible to prevent the rice near the heater 6 from drying or discoloring due to the residual heat of the heater 6, and When the amount of rice is large, it is possible to realize heat retention control that can prevent the temperature outside the vicinity of the heater 6 from becoming low and causing dew condensation to prevent the rice from swelling. Here, it is based on the amount of rice determined during cooking, because it is difficult to measure the amount of rice during warming.

As described above, according to the method for controlling the temperature of a jar rice cooker according to the embodiment of the present invention, the amount of cooked rice is determined during cooking and the amount of power of the heater 6 is changed based on the amount of cooked rice during the warming. In addition, it is possible to perform a heat-retention control according to the amount of rice to suppress drying, swelling, discoloration and the like, thereby maintaining a good heat-retention state.

(Embodiment 2) Next, a second embodiment will be described with reference to FIG.

In FIG. 3, the vertical axis represents the temperature level of rice,
The horizontal axis indicates time. After cooking, the rice is naturally cooled and kept at a low temperature of 1 after cooling time 15
(60 ° C.) so that the temperature of the rice is maintained
Controls the heater 6. Low temperature temperature level 1
(60 ° C.) is a temperature suitable for improving the heat retention performance, but is also a growth temperature (60 ° C. to 75 ° C.) of spoilage bacteria (bacteria belonging to Bacillus staerothermophillus). It is heated to a temperature level of 3 (75 ° C. or higher) for killing spoilage bacterial vegetative cells by 17. Here, the temperature level 1 (60
C.) to a temperature level 3 (75 ° C. or higher), when heating by the heater 6, the electric power by the heater 6 is changed according to the amount of rice obtained at the time of cooking. That is, by increasing the power of the heater 6 when the amount of cooked rice is large, and by decreasing the power when the amount of cooked rice is small, the temperature rise time is controlled to be substantially constant regardless of the amount of cooked rice, and the predetermined time 18 after the start of temperature rise is reduced. It is possible to perform constant control. Thereafter, this heating is repeated at regular intervals to prevent spoilage of the rice.

As described above, according to the method for controlling the temperature of a jar rice cooker according to the embodiment of the present invention, the amount of cooked rice is determined during cooking and the electric power of the heater 6 is changed according to the amount of cooked rice during the temperature maintenance. Since the predetermined time 18 can be kept constant, it is possible to perform a heat-retention control in accordance with the amount of rice by a simple control method, and to maintain a good heat-retention state while preventing rot of rice.

(Embodiment 3) Next, a third embodiment will be described with reference to FIG.

In FIG. 4, the vertical axis represents the temperature level of rice,
The horizontal axis indicates time. After cooking, the rice is naturally cooled and kept at a low temperature of 1 after the cooling time 18
(60 ° C.) so that the temperature of the rice is maintained
Controls the heater 6. As in the case of the second embodiment,
By heating to a temperature level of 3 (75 ° C. or higher) for killing putrefactive bacterial vegetative cells for a killing temperature holding time of 20, the putrefaction is prevented. This dead temperature holding time 2
0 changes depending on the amount of cooked rice obtained at the time of cooking rice. If the amount of cooked rice is large, the time is extended as indicated by a dashed line indicated by 22; if the amount of cooked rice is small, the time is shortened as indicated by a two-dot chain line indicated by 23. Thereafter, this heating is repeated at regular intervals to prevent spoilage of the rice.

As described above, according to the method for controlling the temperature of a jar rice cooker according to the embodiment of the present invention, the amount of cooked rice is determined during the cooking of rice, and at the time of keeping the temperature, the dead temperature holding time 20 is determined by the amount of cooked rice.
To control the heat retention according to the amount of rice,
It can maintain good heat retention while preventing rot of rice.

(Embodiment 4) Next, a fourth embodiment will be described.

This embodiment controls whether or not to provide a plurality of temperature levels at which the temperature is to be kept constant at the time of keeping the temperature in accordance with the amount of cooked rice obtained at the time of cooking. Specifically, the amount of cooked rice is constant. If the amount is less than the amount, control is performed so as to alternately maintain the temperature of the rice at the two heat retention control temperature points. If the amount of cooked rice is a certain amount or more, the rice is always maintained at the temperature level 2 (71 ° C.) as described in the first embodiment. Is controlled as follows. This is intended to improve the heat retention performance when the amount of rice is equal to or more than a certain value. That is, when the amount of rice is a certain amount or more and the temperature of the rice is lowered to the temperature level of low temperature keeping 1 (60 ° C.), then the temperature level 3 for killing spoilage bacterial vegetative cells is obtained.
(75 ° C or higher)
It is necessary to increase the electric power of the heater 6 or prolong the heating time, but in any case, the rice near the heater 6 is likely to be excessively heated, and the trouble such as drying is likely to occur. In addition, the rice far from the heater 6 is hardly heated, and there is a risk that the temperature does not rise to a temperature level 3 (75 ° C. or more) for killing spoilage bacterial vegetative cells. Therefore, as in the present embodiment, if the amount of cooked rice is equal to or more than a certain amount, the temperature level of the normal heat retention during the heat retention is 2 (71).
The temperature of the rice is kept around (° C), and the temperature of the rice is not lowered to a low temperature region where the rice is easily spoiled, so that the rice is prevented from drying and spoiling.

[0031]

As is apparent from the above embodiment, according to the present invention, the amount of rice is determined by the rice cooking amount determining means during rice cooking, so that appropriate heating according to the amount of rice can be performed even when the temperature is maintained. Can be carried out, and the rice can be dried, soaked, discolored, etc., and kept in a good heat-retaining state.

Further, when controlling to maintain the temperature of the rice at the two temperature control temperature points, the electric power of the heater by the heating control means is changed according to the amount of cooked rice determined during cooking. In addition, it is possible to perform more appropriate heat retention control by a simple method.

Further, by changing the length of time during which the temperature of the rice is maintained at the second temperature control temperature point in accordance with the amount of cooked rice determined during the cooking, it is possible to perform finer heat control. It is possible to perform optimal heating according to the amount of rice, suppress changes in odor and color, prevent rot, and keep the rice in a good heat-retaining state.

Further, by limiting the heat retention control based on the two heat retention control temperature points to a case where the amount of cooked rice determined during cooking is less than a predetermined amount of cooked rice, the rice is dried even if the amount of rice is large. It is possible to prevent the rice from being putrefactive and keep the rice in a good heat-retaining state.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electronic jar rice cooker according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a temperature level and a time when the electronic jar rice cooker is kept warm.

FIG. 3 is a diagram showing a relationship between a temperature level and time when the electronic jar rice cooker according to the second embodiment of the present invention is kept warm.

FIG. 4 is a diagram showing a relationship between a temperature level and a time at the time of keeping the temperature of the electronic jar rice cooker according to the third embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the temperature level and the time when keeping the temperature of the conventional electronic jar rice cooker.

[Explanation of symbols]

 5 inner pan 6 heater 7 temperature detecting means 8 heating control means

Continuation of the front page (72) Inventor Haruo Ishikawa 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-7526 (JP, A) JP-A-63-49511 (JP) , A) Japanese Utility Model Hei 2-146527 (JP, U) Japanese Utility Model 56-24029 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/00 103 A47J 27/00 109

Claims (3)

(57) [Claims] 1. An inner pot for putting rice, a heater for heating the inner pot, temperature detecting means for detecting a temperature of the inner pot, and controlling the heater by using an output of the temperature detecting means as an input. Heating control means for performing rice cooking and heat retention, and rice cooking amount determination means for determining the rice cooking amount of the rice put in the inner pot during rice cooking, the rice cooking amount determined by the rice cooking amount determination means during rice cooking Accordingly, the amount of electric power of the heater by the heating control means at the time of heat retention is changed,
The rice cooked amount determined during rice cooking by the rice cooked amount determining means is
If the amount of cooked rice is more than the specified value, heat insulation control is performed at one temperature control temperature point
If the amount of cooked rice is less than the prescribed amount of cooked rice, two heat insulation
A method for controlling the temperature of an electronic rice cooker, which controls the temperature at a control temperature point . 2. An inner pot for putting rice and heating the inner pot
Heater and temperature detecting means for detecting the temperature of the inner pot
And the output of the temperature detection means as an input to the heater
Heating control means to cook rice and keep warm by controlling
And determine the amount of rice cooked in the inner pot during cooking.
Rice cooking amount determination means, and the rice cooking amount determination means
According to the amount of cooked rice determined during cooking, said heating at the time of heat retention
Changing the electric energy of the heater by the control means,
The heating control means alternately sets the temperature of the rice to two temperature control temperature points, a first temperature control temperature point and a second temperature control temperature point, which is a higher temperature point than the first temperature control temperature point. Is controlled so that the rice is cooked by the rice cooking amount determination means.
One if the amount of cooked rice determined during the rice is above a predetermined amount of cooked rice
Insulation control is performed at the temperature control point of
A method for controlling the temperature of an electronic rice cooker in which the temperature is controlled at two temperature control points if the amount is less than the amount of rice . 3. An inner pot for putting rice and heating the inner pot.
Heater and temperature detecting means for detecting the temperature of the inner pot
And the output of the temperature detection means as an input to the heater
Heating control means to cook rice and keep warm by controlling
And determine the amount of rice cooked in the inner pot during cooking.
Rice cooking amount determination means, and the rice cooking amount determination means
According to the amount of cooked rice determined during cooking, said heating at the time of heat retention
Changing the electric energy of the heater by the control means,
The heating control means includes: a first heat retention control temperature point;
The second heat insulation system which is a temperature point higher than the first heat insulation control temperature point
Alternating the temperature of rice to the two temperature control temperature points
Controlled to be to keep, in response to said cooking amount determined during cooking by cooking amount determining means, will by changing the length of time to keep the temperature of the rice to the second insulation control temperature point, before
The rice cooked amount determined during the rice cooking by the rice cooked amount determining means is
If the amount of cooked rice is above a certain level, heat control at one heat control temperature point
If the amount of cooked rice is less than the prescribed amount of cooked rice, two heat insulation systems
A method for controlling the temperature of an electronic rice cooker that controls the temperature at a temperature point .