JPH09164076A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop rice cooking heating in the initial stage when rice cooking is started while no water is put into a pot or no pot is fitted and dispense with a pot switch detecting the fitting/removing of the pot. SOLUTION: When the detected temperature Tu of a heat radiating plate sensor becomes 115 deg.C or above after rice cooking is started, it is judged that empty heating is in progress, and the excitation to a rice cooking heater is stopped. When the detected temperature Tu has a rising rate of 1 deg.C or below in three minutes during the normal rice cooking operation, the excitation to a cover heater is started, and the temperature of a heat radiating plate is kept at about 20 deg.C thereafter. When a rice cooker is normally shifted from rice cooking to heat retention, the detected temperature Ti of a pot inner sensor is compared with the detected temperature Td of a pot bottom sensor. If Ti<Td, the cover heater is excited. If Ti>=Td and Ti+0.5 deg.C>=Tu, the cover heater is excited. If Ti+0.5 deg.C<Tu, the excitation to the cover heater is stopped.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a rice cooker for cooking rice by heating a pot containing rice and water.

[0002]

2. Description of the Related Art Conventionally, in a general electric rice cooker, an inner lid separate from the lower surface member is detachably attached to a lower surface member of a lid covering an opening of the pan, and the inner lid is opened and closed. The opening is closed by closing the opening.

[0003] A lid heater is provided on the back surface of the lower surface member of the lid, and the lid heater is heated by radiant heat. However, if a separate inner lid is arranged on the lower surface side of the lid, it is required to prevent dew condensation on the upper and lower surfaces of the inner lid and the three surfaces on the lower surface side of the lid. However, there is a problem that the heat generation capacity must be increased.

Therefore, in recent years, Japanese Utility Model Laid-Open No. 2-78 has been proposed.
As seen in No. 122, without using the inner lid, the lower surface member of the lid body is directly closed to the opening of the pan and closed, and a lid heater is disposed on the back side of the lower surface member, and rice cooked by the lid heater There has been proposed a rice cooker in which a lower surface member is heated at the time of heating or at the time of heat retention. In this publication, the dew condensation is only on the lower surface member, so that the heating capacity of the lid heater can be reduced, and the radiant heat from the lower surface member can be directly radiated to the rice, so that the heating efficiency is improved and the entire container is evenly distributed. It can cook and keep warm.

[0005]

However, in the rice cooker having such a structure, when the rice is started without forgetting to put water in the pan, the rice is continuously cooked in an empty state and wasteful power consumption is performed. There was a problem that the pot became abnormally hot.

[0006] Further, since the pan switch is used to detect the attachment / detachment of the pan in order to prevent the rice from starting to be cooked without mounting the pan on the rice cooker body, the structure of the mechanism for mounting the pan switch becomes complicated. There was a problem.

Therefore, the invention is to start cooking rice by forgetting to put water in the pan and start cooking rice without attaching the pan to the main body of the rice cooker. It can be stopped to prevent unnecessary power consumption and prevent the pan from becoming abnormally hot, and since the pan switch is not required, the configuration can be simplified.
It is possible to prevent soaking as much as possible due to dew condensation on the lower surface of the lid during rice cooking control and heat retention control, and to reduce power consumption by reducing the heating amount to prevent the soaking on the lower surface of the lid. Provide a rice cooker.

[0008]

According to the first aspect of the present invention,
A pot that is detachably provided in the rice cooker body, a lid that covers the opening of the pot, a lid heating unit that heats the lower surface of the lid that directly faces the pot, and a pot heating unit that heats the pot. Prepare and continue cooking rice by selecting to stop cooking rice when rice cooking is started when the rice cooker body is not equipped with a pan, or when the rice cooker is installed but there is no rice in the pan. In such a case, the lid heating means is operated during the steam generation period from the cooked rice in the pan, and the operation of the lid heating means is continued even after the rice is kept warm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 shown in FIG. 1 is a cooking pot. The rice cooker main body is constituted by the inner frame 2, the outer frame 3 and the frame 4, and the pot 1 is removably stored in the inner frame 2.

A heat sensitive device 5 is provided at the center of the bottom portion of the inner frame 2, and a rice cooking heater 6 is provided on the outer periphery of the heat sensitive device 5 as a pot heating means. A heat retaining heater 7 is attached to the upper portion of the outer side surface of the inner frame 2.

At the bottom of the outer frame 3, a control unit 8 containing a control circuit described later is attached. 9 is pot 1
Is a lid that covers the opening of FIG. Inside the lid 9, a radiator plate 10 which constitutes the lower surface of the lid 9 and is directly opposed to the opening of the pan 1 is attached. The surface of the radiator plate 10 facing the pan 1 is coated with a resin, For example, a fluorine resin coat is applied. The durability temperature of this fluororesin coat is 250 ° C. or less.

A lid heater 11 is provided as a lid heating means on the back surface of the heat radiating plate 10. The lid heater 11 is covered with a heat shield plate 12 so that heat from the lid heater 11 does not reach the lid body 9. It is being appreciated.

Inside the heat-sensitive device 5, the pot bottom temperature Td
Is provided at a portion projecting downward from the center of the lid 9, a pan upper temperature Ti,
That is, the sensor 1 in the pot that detects the temperature of the rice in the pot
4, a radiator plate sensor 15 for detecting the radiator plate temperature Tu is provided on the back surface of the radiator plate 10 near the lid heater 11 surrounded by the radiator plate 10 and the heat shield plate 12. . Each of these sensors 13, 14 and 15 is a sensor that detects the temperature.

As shown in FIG. 1, the lid heaters 11 are arranged side by side in a plurality of rows on the outer peripheral portion of the heat dissipation plate 10. The heat dissipation plate sensor 15 is provided on the back surface of the heat dissipation plate 10 in a region inside the lid heater 11.

FIG. 2 is a block diagram showing a circuit configuration.
Is a microcomputer constituting the control unit body.
An analog output of the pan bottom sensor 13 that has detected the pan bottom temperature Td is converted into a digital signal by a first A / D converter 22 and supplied to the microcomputer 21.

The analog output of the radiator plate sensor 15 which has detected the radiator plate temperature Tu is converted into a digital signal by the second A / D converter 23 and supplied to the microcomputer 21.

The analog output of the in-pot sensor 14 which has detected the pot upper temperature Ti is converted into a digital signal by the third A / D converter 24 and supplied to the microcomputer 21.

A clock circuit 25 for measuring the current time and the time of each cooking process is connected to the microcomputer 21. The operation unit 26 is connected to the microcomputer 21 and inputs various initial settings and manual operations.

The microcomputer 21 controls the display section 28 via the display section control circuit 27. The microcomputer 21 controls a heater switch unit 30 which directly controls the energization of the rice cooking heater 6, the heat retaining heater 7 and the lid heater 11 via a heater control circuit 29 which also constitutes a lid heating control means. I have.

As shown in FIG. 3, the heater switch unit 30 has a commercial power supply 31, a rice cooking heater 6 and a switch 32 (hereinafter referred to as SW32) as a first closed circuit.
Are connected in series.

As the second closed circuit, the commercial power source 31, the rice cooking heater 6, the heat retaining heater 7 and the switch 33 are provided.
(Hereinafter, referred to as SW33) are connected in series.
As the third closed circuit, the commercial power supply 31 and the lid heater 1
1 and a switch 34 (hereinafter referred to as SW34) are connected in series.

FIG. 4 is a flow chart showing the rice cooking control by the microcomputer 21, and when this control is entered, the SW 32 is turned on and power is supplied to the rice cooking heater 6.

It is determined whether the detected temperature Tu of the heat sink sensor 15 is 115 ° C. or higher, and the detected temperature Tu is 115 ° C.
If it is above, it is determined that the rice is in the empty cooking state and the SW32 is turned off.
F. Perform empty cooking.

If the detected temperature Tu is lower than 115 ° C., it is next judged whether or not the rate of increase of the detected temperature Tu per 3 minutes is 1 ° C. or less. The rise rate of the detection temperature Tu per 3 minutes is 1 ° C
Is exceeded, the process returns to the process of turning on the SW 32 again. If the detected temperature Tu is less than 115 ° C. and the rate of increase per 3 minutes is 1 ° C. or less, the SW
34 is turned on to supply power to the lid heater 11.

Next, the temperature Td detected by the pan bottom sensor 13
It is determined whether or not the detected temperature Td is equal to or higher than 120 ° C.
If the temperature is lower than 0 ° C., it is determined whether the detected temperature Tu of the heat sink sensor 15 is 200 ° C. or higher.

If the detected temperature Tu of the heat sink sensor 15 is 200 ° C. or more, the SW34 is turned off, and if the detected temperature Tu is less than 200 ° C., the SW34 is turned on. In any case, The process returns to the process of determining whether the temperature Td detected by the pan bottom sensor 13 is 120 ° C. or higher. When the detected temperature Td of the pan bottom sensor 13 becomes 120 ° C. or higher, the SW 32 is turned off to stop supplying power to the rice cooking heater 6.

Next, the clock circuit 25 causes the SW 32 to turn off.
The time after the FF is measured, and it is determined whether or not the measured time has elapsed 15 minutes. If 15 minutes have not passed,
It is determined whether or not the detected temperature Tu of the heat sink sensor 15 is 200 ° C. or higher.

The detected temperature Tu of the heat sink sensor 15 is 20
If the temperature is 0 ° C. or more, the switch SW34 is turned off, and the detection temperature Tu
Is lower than 200 ° C., the switch SW34 is turned on. In any case, the clock circuit 2 is turned on again.
The process returns to the process of determining whether or not the measurement time measured by step 5 has elapsed 15 minutes.

When the time measured by the clock circuit 25 has passed 15 minutes, the temperature control is started. FIG. 5 is a flowchart showing the heat retention control by the microcomputer 21. Upon entering the heat retention control, it is determined whether or not the detected temperature Td of the pan bottom sensor 13 is lower than 71 ° C.
If the detected temperature Td is 71 ° C. or higher, the switch 33 is turned off.

In any case, the sensor 1 in the pan is then continued.
4 is the detected temperature Td of the pan bottom sensor 13
Is less than or equal to. If the detected temperature Ti is lower than the detected temperature Td, the SW 34 is turned on,
The process returns to the process of determining whether the detected temperature Td is lower than 71 ° C. again.

If the detected temperature Ti is equal to or higher than the detected temperature Td, it is determined whether or not the temperature obtained by adding 0.5 ° C. to the detected temperature Ti is lower than the detected temperature Tu of the radiator plate sensor 15. If the temperature obtained by adding 0.5 ° C. to the detected temperature Ti is equal to or higher than the detected temperature Tu, the SW 34 is turned on. If the temperature obtained by adding 0.5 ° C. to the detected temperature Ti is smaller than the detected temperature Tu, The SW 34 is turned off, and in any case, the process returns to the process of determining whether or not the detected temperature Td of the pan bottom sensor 13 is lower than 71 ° C.

In such a structure, when rice cooking is started, heating is first started by the rice cooking heater 6. At this time, if there is no water in the pot 1 along with rice, or if the pot 1 itself is not cooked, the temperature of the heat sink 10 will rise rapidly, When the detection temperature Tu of the plate sensor 15 reaches 115 ° C., the power supply of the rice cooking heater 15 is immediately stopped. Thereby, safety is ensured.

When water is normally contained in the pot 1 together with rice, the water boils due to heating and reaches an equilibrium temperature near 100 ° C., and at that time, the temperature Tu detected by the radiator plate sensor 3 is 3 The rate of increase per minute becomes 1 ° C. or less, and heating of the radiator plate 10 by the lid heater 11 is started. That is, heating of the radiator plate 10 by the lid heater 11 is started during a period in which water boils and steam is generated.

Then, the temperature Td detected by the pan bottom sensor 13
Until the temperature reaches 120 ° C., the lid heater 11 is energized and controlled so that the detected temperature Tu of the heat dissipation plate sensor 15 is maintained at 200 ° C. The detected temperature Td of the pan bottom sensor 13 is 1
When the temperature reaches 20 ° C. or higher, the power to the rice cooker 6 is stopped.

After that, until 15 minutes have elapsed, the lid heater 11 is energized and controlled so that the detected temperature Tu of the radiator plate sensor 15 is maintained at 200 ° C. Thereby, so-called spotting is performed. And after 15 minutes have passed,
Shift to heat retention control. In this heat retention control, energization of the heat retention heater 7 is controlled such that the detection temperature Td of the pan bottom sensor 13 is maintained at 71 ° C.

At the time of this heat retention, even if the temperature Ti detected by the pan sensor 14 becomes lower than the temperature Td detected by the pan bottom sensor 13 or the temperature Ti detected by the pan sensor 14 is equal to or higher than the temperature Td detected by the pan bottom sensor 13. The detected temperature Tu of the heat sink sensor 15 is the detected temperature Ti of the in-pan sensor 14.
When the temperature is equal to or lower than 0.5 ° C., power is supplied to the lid heater 11, and the temperature Ti
When the temperature is equal to or higher than the detection temperature Td of the pan bottom sensor 13 and the detection temperature Tu of the heat sink sensor 15 is higher than the temperature obtained by adding 0.5 ° C. to the detection temperature Ti of the sensor 14 in the pan, the power supply to the lid heater 11 is stopped. I do.

As described above, when the rice is not cooked in the pot 1 or the rice is started without the pot 1 itself being mounted, the temperature of the heat sink 10 is rapidly increased, Since the heat dissipation plate sensor 15 detects that the rice cooker is in an empty state and immediately stops the power supply to the rice cooking heater 15, wasteful power consumption can be prevented and an abnormal temperature rise of the rice cooker can be prevented. Moreover, since a pan switch for detecting attachment / detachment of the pan 1 is not required, the structure can be simplified.

Further, during the rice cooking control in which the rice is normally cooked, the heat radiating plate 1 is used during the period in which water boils and steam is generated.
Since the temperature of 0 is maintained at about 200 ° C., it is possible to prevent condensation of the heat radiating plate 10 due to water vapor as much as possible. Further, at the time of the heat retention control, the temperature of the heat radiation plate 10 is maintained at a temperature higher by 0.5 ° C. than the detection temperature Ti of the in-pan sensor 14, so that the heat radiation plate 10 is condensed during the heat retention and becomes in a sticky state. Can be prevented as much as possible. Further, the heating by the lid heater 11 may be performed by heating only the heating plate 10 which directly faces the inside of the pan.
Power consumption can be reduced by reducing the heating amount of the lid heater 11.

[0039]

As described above, according to the present invention,
If you forget to put water in the pan and start cooking rice, and if you start cooking rice without mounting the pan on the rice cooker body, the rice heating by the pan heating means will be stopped at the beginning of rice cooking control and power consumption will be wasted. In addition, the pan can be prevented from abnormally high temperature, and since the pan switch is not required, the configuration can be simplified.Furthermore, dew condensation due to dew condensation on the bottom surface of the lid during rice cooking control and heat retention control. It is possible to provide a rice cooker that can prevent sticking as much as possible, and can reduce power consumption by reducing the amount of heating for preventing the bottom surface of the lid body from being steamed.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a circuit configuration of the rice cooker according to the embodiment.

FIG. 3 is a circuit configuration diagram of a heater switch unit of FIG. 2;

FIG. 4 is a flowchart showing rice cooking control by the microcomputer of FIG. 2;

FIG. 5 is a flowchart showing heat retention control by the microcomputer of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pan 6 ... Rice cooking heater (pot heating means) 7 ... Heat insulation heater 9 ... Lid body 10 ... Radiating plate 11 ... Lid heater (lid heating means) 21 ... Microcomputer 30 ... Heater switch part

Claims (1)

[Claims] 1. A pot that is detachably attached to the rice cooker body,
A lid that covers the opening of the pot, a lid heating unit that heats the lower surface of the lid that directly faces the pot, and a pot heating unit that heats the pot are provided, and the pot is attached to the rice cooker body. If you don't wear it, or if you don't, or if you don't have any rice in the pan, choose to stop cooking when you start cooking. A rice cooker characterized in that the lid heating means is operated during a period of steam generation from the cooked rice, and the operation of the lid heating means is continued even when the temperature is kept after the rice is cooked.