JPH0662951A - Rice boiler - Google Patents

Abstract

PURPOSE:To provide boiled rice which tastes good at any time, by a method wherein such problems that the boiled rice is made dry, is turned yellow and smells of thermal insulation are lessened even if the boiled rice is thermally retained for a long time, and such problems that the temperature of the boiled rice is made unequal and is changed, due to room temperature are also lessened. CONSTITUTION:A lid heater 4 performs both heating control wherein an electric current is long applied thereto and its temperature becomes high in order that the amount of dew adhering to the side of a vessel 1 of a lid 3 is allowed to decrease in the process of boiling rice and temperature control wherein duty heating, the electric current is repeatedly intermittently applied thereto, is performed in order that heat-retaining temperature of the vessel 1 or the lid 3 is maintained in the process of retaining heat. In addition, in the process of retaining the heat, a programs, in which the ratio between a bottom heater 2 and the lid heater 4 with regard to heating amount for a fixed time T is preset, controls their heating as a unit process in which the electricity is turned on for the fixed time T, on the basis of the temperature information from a thermal sensor 9 for detecting bottom temperature. In this way, the heat- retaining temperature of the vessel 1 is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker mainly used at home and having a heat retaining function.

[0002]

2. Description of the Related Art In recent years, rice cookers not only improve rice cooking performance, but also reduce the amount of dew that adheres to the lid during rice cooking to reduce the amount of dew drop when the lid is opened and eliminate the dew drop. of,
It is also desired to improve usability.

However, conventionally, in order to improve the deliciousness of rice,
Although the rice cooking performance was the main focus, and the heat retention performance was not so much examined, the need for people to eat delicious rice even when kept warm for a long time has increased due to the advancement of women in society and the 24-hour society. However, it is necessary to take measures such as drying during heat retention and yellowing of rice.

A conventional rice cooker will be described below with reference to FIGS. The structure of a conventional rice cooker will be described with reference to FIG. In the figure, 31 is a pot for putting rice and water, 32 is a bottom heater that heats the pot 31, 33 is a lid that covers the top of the pot 31, 34 is a lid heater that closely heats the lid, and 35 is a removable lid 33. Inner lid, 36 that closes the pan 31
Is an outer lid that constitutes the outer shell of the lid 33, 37 is a protective frame arranged outside the pot 31, 38 is a side heater that closely heats the protective frame 37, and 39 is a bottom temperature that senses the temperature of the bottom of the pot 31. A sensor 40, a lid temperature sensor that senses the temperature of the lid 33, 41 a bottom heater 32, a lid heater 34, and a side heater 3 according to the temperature information of the bottom temperature sensor 39 and the lid temperature sensor 40 and the set program.
8 is a control circuit for controlling 8, and 42 is a microcomputer in which the program in the control circuit 41 is incorporated.

Next, a heating circuit of a conventional rice cooker will be described with reference to FIG. In the figure, 43 is a relay for switching between single energization of the bottom heater 32 by NO and serial energization of the bottom heater 32, the lid heater 34, and the side heater 38 by NC.
Reference numeral 4 is a triac which is ON to energize the bottom heater 32, the lid heater 34 and the side heater 38 in series, and is OFF to stop energization.

With respect to the rice cooking process and the heat retaining process of the conventional rice cooker configured as described above, the operation thereof will be described below with reference to FIG.

FIG. 7 shows the operation. The vertical axis shows the heating amount (W) by the bottom heater 32, the lid heater 34, and the side heater 38, and the temperature of the pan 31 and the lid temperature detected by the bottom temperature sensor 39. The lid 3 detected by the detection sensor 40
The temperature is 3 and the horizontal axis is time.

In the figure, when an operation switch (not shown) is turned on, the control circuit 41 is operated by the program of the microcomputer 42. First, in the rice cooking process, set the relay 43 to NO.
Then, the bottom heater 32 is energized to heat the pan 31 containing rice and water, and steam is generated to boil the rice. When the free water disappears due to the absorption and evaporation of rice and the pot 31 reaches 130 ° C. or higher and the bottom temperature sensor 39 senses the temperature, the relay 43 is set to NC and the energization of the bottom heater 32 is stopped. During this time, the triac 44 is in the OFF state. Next, the relay 43
NC and TRIAC 44 are turned on and the bottom heater 32
By energizing the lid heater 34 and the side heater 38, the lid heater 34 having a high resistance value becomes highly heated to heat the lid 33, reduce the dew condensation of the lid 33 due to steam, and open the lid 33 after the rice cooking process is completed. The dew drop is reduced to reduce the amount of dew drop.

Here, in order to reduce the dew condensation on the lid 33 due to steam, the lid heater 34 needs to have a high heating amount and also needs to be energized for a long time. The higher the heating power (W) of the lid heater 34 is, the more the temperature becomes 100 ° C. or higher in a short time, the less the amount of dew condensation due to the generation of steam becomes, and the dew that has condensed in a short time can be vaporized. However, the lid temperature detection sensor 4 does not reach an abnormal temperature.
100 ° C set in the control circuit 41 by the temperature information of 0
The heating temperature is controlled at the above temperature.

In the heat retaining step, the bottom heater 32, the lid heater 34, and the side heater 38 are energized in series by NO of the relay 43. The control circuit 41 controls the energization of the triac 44 based on the temperature detection information of the bottom temperature detection sensor 39. That is, when the temperature is equal to or lower than the heat retention temperature set in the control circuit 41, the bottom heater 32, the side heater 38, and the lid heater 34 are simultaneously energized to heat the pot 31, and when the heat retention temperature is exceeded,
The bottom heater 32, the side heater 38, and the lid heater 34 are simultaneously de-energized and the pot 31 is not heated. By continuing this control operation, the heat retention temperature of the pot 31 is maintained and controlled.

[0011]

However, in the conventional rice cooker, the heating amount of the lid heater 34, which is a high heating amount in order to reduce the dew condensation of the lid 33 due to the steam, is the same as that of the bottom heater 32. Since the heating amount of the side heater 38 is larger than that of the pan and the lid 33 has a high heating balance, the surface of the rice becomes dry and becomes a hard rice grain in a heat-retaining state for a long time. There was a problem in that, while the feeling was felt, the yellowing of rice and the heat-retaining odor also increased, resulting in a loss of appetite.

The lid heater 34 for controlling the heat retention temperature
There is a problem that the temperature ripple of the lid 33 becomes large due to the ON / OFF heating of No. 3, and the surface temperature of the rice becomes high at the maximum ripple temperature at the time of ON, and the rice further dries.

Further, due to the above-mentioned heating during the heat retention operation, the temperature of the rice in the pan 31 is greatly varied and the temperature of the rice is greatly changed due to the change in the room temperature of the product. Had. In other words, when the room temperature is low, a high heating amount is required to maintain the heat retention temperature of the rice, and the heaters 32, 34, 38 are used for a long time.
Works. Since the lid heater 34 has a strong heating balance by this heat retention heating, the rice is mainly heated from the lid 33, and the temperature difference in which the upper part of the rice becomes high temperature and the lower part becomes low temperature becomes large, and the temperature unevenness of the rice becomes large. . The heating of the lid heater 34 is performed by the bottom heater 32 and the side heater 3
8 will be supplemented by heating to heat the rice in the pan 31 while keeping it warm.
The bottom temperature of the pan 31 having 9 is lower than the surface of the rice, and the temperature of the entire upper rice layer becomes higher. Further, when the room temperature is high, a low heating amount is required to maintain the heat retention temperature of the rice, and each heater 32, 3 for a short time is required.
4, the bottom temperature of the pan 31 having the bottom temperature detection sensor 39 for detecting the heat retention temperature is slightly lower than the rice surface, and the temperature of the whole rice upper layer does not become so high.

The present invention solves the above-mentioned problems and reduces the heat and odor of rice by drying and yellowing it even if it is kept warm for a long time, and reduces the uneven temperature of rice and the temperature change of rice at room temperature. The purpose is to provide rice that can be eaten anytime.

[0015]

In order to achieve the above object, the first means of the present invention is that the lid heating means reduces the amount of dew adhered to the pot side of the lid during the rice cooking process with a long energization. A high temperature heating control and a duty heating temperature control for repeating energization and stopping for maintaining the heat retaining temperature of the pot or the lid during the heat retaining step are performed.

A second means of the present invention for attaining the above object is a program for setting a heating amount ratio of a constant T time between the bottom heating means and the lid heating means during the heat retaining step, wherein the temperature information of the temperature sensing means is set. Thus, the heating temperature of the pot is controlled by controlling the heating in units of energization for the time T.

[0017]

According to the first means described above, the lid heating means that is heated to a high level (W) to reduce the amount of dew condensation during the rice cooking step is duty heating control that repeats energizing and stopping during the heat retaining step. Therefore, the heating ripple of the lid is small and it can be an average heating, high heating that does not attach dew to the lid during the rice cooking process, and the temperature of the lid with the lid heater becomes average during the heat retention process, and the pot bottom with the bottom heater The temperatures of and will be balanced, and the temperature of the rice in the pan will be balanced on average.

According to the second means, during the heat retention step,
The temperature of the rice in the pan is kept constant for a fixed T time by controlling the heating and energizing of the bottom heating means and the lid heating means for a fixed T time according to the temperature balance of the rice in the pan.
During long-time heat retention temperature control in which energization of time is repeated,
The temperature of the rice in the pan can be balanced. Moreover, in order to maintain the heat retention temperature of the rice by changing the room temperature and the voltage, even when the heating energizing amount of the bottom heating means and the lid heating means, that is, the heating energizing time is changed, Since the temperature of the rice is well balanced, the temperature control will be well balanced for a long time.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First, the structure of the rice cooker of the present invention will be described with reference to FIG. In the figure, 1 is a pot for putting rice and water, 2 is a bottom heater for heating the pot 1, 3 is a lid for covering the top of the pot 1, 4
Is a lid heater that heats closely to the lid, 5 is an inner lid that closes the pot 1 that is detachably attached to the lid 3, 6 is an outer lid that forms the outer shell of the lid 3, and 7 is a protection placed outside the pot 1. Frame, 8 is a side heater that heats closely to the protective frame 7, 9 is a bottom temperature sensor that senses the temperature of the bottom of the pot 1, 10 is a lid temperature sensor that senses the temperature of the lid 3, 11 is the bottom temperature A control circuit for controlling the bottom heater 2, the lid heater 4, and the side heater 8 according to the temperature information of the detection sensor 9 and the lid temperature detection sensor 10 and a set program, and 12 is a microcomputer having a program built therein.

Next, the heating circuit configuration will be described with reference to FIG.
In the figure, 13 is a triac A for energizing the bottom heater 2, 14 is a triac B for energizing the lid heater 4,
Reference numeral 15 is a triac C for energizing the side heater 8.

The operation of the rice cooking process and the heat retaining process of the conventional rice cooker configured as described above will be described below with reference to FIG.

FIG. 3 shows the operation. The vertical axis shows the heating amount (W) by the bottom heater 2, the lid heater 4, and the side heater 8, and the temperature of the pot 1 and the lid temperature detected by the bottom temperature sensor 9. The temperature of the lid 3 sensed by the sensing sensor 10 is plotted along the horizontal axis.

In the figure, when an operation switch (not shown) is turned on, the control circuit 11 is operated by the program of the microcomputer 12. First, in the rice cooking process, TRIAC A1
When the switch 3 is turned on, the bottom heater 2 heats the pot 1 containing rice and water. When the lid temperature detection sensor 10 senses the lid 3 whose temperature has risen due to steam generation, the triac B14 is energized to heat the lid heater 4 to reduce the dew condensation of the lid 3 due to the steam, and the lid is heated after the rice cooking process. The amount of dew drop when opening 3 is reduced to eliminate the dew drop.

Here, in order to reduce the dew condensation on the lid 3 due to the steam, a high heating amount is required, and the lid heater 4 is energized for a long time. The higher the heating power (W) of the lid heater 4, the temperature rises to 100 ° C. or higher in a short time, and the amount of dew condensation due to the generation of steam decreases, so that the dew that has condensed in a short time can be vaporized. However, the heating temperature is controlled at a temperature of 100 ° C. or higher set in the control circuit 11 by the temperature information of the lid temperature detection sensor 10 so that the abnormal temperature is not reached.

In the heat retaining step, the heat retaining program is set to set the heating amount ratio for the constant T time shown in FIG. Constant T
Insulation program that sets the heating amount ratio of time is pot 1
The heating amount ratio of the pot 1 which can keep the temperature for keeping the rice warm inside is calculated separately for the bottom, the lid and the side face, and each heating amount ratio is divided by the heating power (W) of each heater to obtain each heating energization ratio.
The energization time is set according to the calculated heating energization ratio, the heating energization time of the shortest heater (in the present invention, the bottom heater 2) is set to, for example, 1 second, and the heating energization time of each of the other heaters is set according to the ratio. To set. In the heat retention program of the constant T time shown in FIG. 4 as an example, the energization ratio time for the constant time of 20 seconds is 800 W for 1 second, the bottom heater 2 is 80 W for 10 seconds, and the side heater 8 is 8 seconds. It is energized at 80 W for 20 seconds. Also, the lid heater 4
Averaging heating is a duty energization control in which energization for 10 seconds is repeated (ON) for 1 second and stopped (OFF) for 1 second.

The operation of the heat retention step is performed by the bottom temperature sensor 9
The control circuit 11 controls the energization of the triac A13, the triac B14, and the triac C15 by the heat retention program based on the temperature sensing information. That is, the bottom temperature sensor 9
When the temperature sensing is lower than the warming temperature set in the control circuit 11, the warming program is forcibly energized for a constant T time (20 seconds as an example of the present invention), and the bottom heater is energized at the warming program energization ratio of FIG. 2, the side heater 8 and the lid heater 4 are energized to heat the pot 1. Further, when the temperature exceeds the heat retention temperature, the bottom heater 2, the side heater 8 and the lid heater 4 are simultaneously de-energized so that the pot 1 is not heated. By continuing this control operation, the rice warming temperature in the pan 1 is maintained and controlled.

As described above, in this embodiment, the lid heater 4 is used.
However, by performing duty heating control that repeats energization and stoppage during the heat retention step, the heating ripple of the lid 3 with a small heat mass is reduced, and it is possible to achieve average heating control, and a pan that is directly affected by heating from the lid 3 It significantly reduces the dryness and yellowing of the rice surface in 1. Moreover, the lid heater 4 can perform high heating (W) regardless of the heat retaining performance by the duty heating control of the heat retaining process, and the amount of dew condensation on the lid 3 and the inner lid 5 can be increased by the high heating during the rice cooking process. It is greatly reduced so that dew does not adhere further to the lid.

During the heat-retaining process, the heating and energizing control of the bottom heater 2, lid heater 4 and side heater 8 for a fixed T time in accordance with the temperature balance of the rice in the pan 1 controls the rice in the pan for a fixed T time. Since the temperature balance is maintained, the temperature of the rice in the pan can be balanced during the long-time heat retention temperature control in which the energization is repeated for a constant T time. Moreover, even if the room temperature changes or the voltage changes, the amount of repeated heating and energization of the bottom heater 2, the lid heater 4, and the side heater 8 for maintaining a constant temperature of the rice for a fixed T time only changes. Since the temperature of the rice in the pan 1 is balanced for a fixed time T, the temperature unevenness between the upper and lower parts of the rice in the pan 1 is reduced and the rice is cooked during the repeated long-term heat retention temperature control. The temperature change of the rice is reduced, the temperature of the rice in the pan 1 is balanced, and the rice is not dried, yellowed, or has a warm odor.

[0030]

As is apparent from the above description of the embodiments,
According to the first means of the present invention, the lid heater having high heating (W) for reducing the amount of dew condensation during the rice cooking process is:
By performing duty heating control that repeats energizing and stopping during the heat retention process, the heating ripple of the lid is reduced and average heating control can be achieved, greatly reducing the drying and yellowing of the rice surface in the pan. Allows delicious rice even if kept warm for a long time. In addition, the lid heater can perform high heating (W) regardless of the heat retention performance by duty heating control of the heat retention process, and the high heating during the rice cooking process significantly reduces the amount of dew condensation, so that the lid is exposed. It will improve the usability every time.

According to the second means, during the heat retention step,
The temperature of the rice in the pan is balanced for a fixed T time by controlling the heating and energization of the bottom heater, lid heater, and side heaters for a fixed T time that matches the temperature balance of the rice in the pan. The temperature of the rice in the pan is balanced during the long-term heat retention temperature control, and even if the room temperature changes or the voltage changes, the number of heating energizations for a fixed T time that maintains the heat retention temperature of the rice It only changes, and the temperature of the rice in the pan for a certain T time is balanced, so the temperature control is kept well balanced for a long time, and the temperature unevenness between the upper and lower parts of the rice in the pan is reduced. At the same time, the change in the temperature of the whole rice becomes small, and the dryness, yellowing, and heat retention odor of the rice becomes very small, and the rice can be eaten deliciously even if it is kept warm for a long time.

[Brief description of drawings]

FIG. 1 is a sectional view of a rice cooker showing an embodiment of the present invention.

FIG. 2 is a heating circuit configuration diagram of the same embodiment.

FIG. 3 is a process operation diagram of the embodiment.

FIG. 4 is an operation diagram of a heat retention program of the same embodiment.

FIG. 5 is a sectional view of a conventional rice cooker.

FIG. 6 is a heating circuit configuration diagram of the conventional rice cooker.

FIG. 7 is an operation diagram of a heat retention program of the conventional rice cooker.

[Explanation of symbols]

 1 Pan 2 Bottom heater 3 Lid 4 Lid heater 8 Side heater 9 Bottom temperature sensor 11 Control circuit

Claims (2)

[Claims] 1. A pan provided with rice and water, a lid heating means for heating a lid arranged on the top of the pot, and a control circuit for controlling the lid heating means according to a set program. By the operation, the lid heating means controls the heating of a high temperature with long energization to reduce the amount of dew adhered to the pot side of the lid during the rice cooking process, and maintains the heat retaining temperature of the pot or the lid during the heat retaining process. A rice cooker that controls duty heating temperature by repeating energizing and stopping. 2. A bottom heating means for arranging at the bottom of the pan to heat the pan, a temperature sensing means for sensing the temperature of the pan, and the pot heating means by temperature information of the temperature sensing means and a set program. A control circuit for controlling the lid heating means is provided, and a constant T of the bottom heating means and the lid heating means is maintained during the heat retention step.
2. The rice cooker according to claim 1, wherein the program in which the heating rate ratio of time is set controls the heating temperature of the pot by controlling the heating in units of energization for the constant T time based on the temperature information of the temperature sensing means.