JPH09164068A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flowing down of waterdrops when a cover body is opened by suppressing dew condensation on a heat radiating plate which is the lower face member of the cover body. SOLUTION: This rice cooker is provided with a cover body 9 covering the opening section of a pot 1, a heat radiating plate 10 forming the lower face of the cover body 9 and directly facing the pot 1, a cover heater 11 heating the heat radiating plate 10, and a heat radiating plate sensor 15 detecting the temperature of the heat radiating plate 10. If the temperature detected by the heat radiating plate sensor 15 is the prescribed temperature or below during the prescribed period before starting heat retention after rice cooking is started, the heat radiating plate 10 is heated by the cover heater 11. If the detected temperature exceeds the prescribed temperature, the heating of the heat radiating plate 10 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 In a conventional general electric rice cooker, an inner lid separate from the lower surface member is detachably attached to a lower surface member of a lid that covers the opening of the pan, and the inner lid is attached to the opening portion of the pan. To close the opening.

A lid heater is provided on the back surface of the lower surface member of the lid, and the radiant heat of the lid heater heats the inner lid and the upper portion of the pot. However, if a separate inner lid is arranged on the lower surface side of the lid, heat radiated from the lid heater into the pot is blocked by the inner lid, and the heating efficiency is reduced.

Therefore, in recent years, Japanese Utility Model Laid-Open No. 2-78 has been proposed.
As seen in No. 122, the inner lid is not used, the lower surface member of the lid body is directly closed and closed to the opening of the pan, and the upper portion in the pan is based on the lid heater arranged on the back surface side of the lower surface member. There has been proposed a rice cooker that directly emits radiant heat to improve heating efficiency.

[0005]

By the way, the water vapor in the pan is condensed and adheres to the lower surface member of the lid. Then, the lid is opened after shifting from rice cooking to warming, but at this time, the condensed water droplets flow down to the one end side of the lid along the lower surface member, and the water droplets flow into the pan to improve the taste of cooked rice. There is a risk that water drops that have dropped or that have run off may adhere to the user's fingers and the like.

The present invention has been made by paying attention to such a point, and an object thereof is to suppress the dew condensation on the heat dissipation plate which is the lower surface member of the lid and to prevent the drop of water when the lid is opened. It is to provide a rice cooker that can prevent.

[0007]

In order to achieve the above-mentioned object, the present invention has a lid for covering the opening of the pot, and a heat radiating plate which constitutes the lower surface of the lid and directly faces the pot. The lid heating means that heats the heat sink, the heat sensitive means that detects the temperature of the heat sink, and the heat sensitive means senses between the time when the rice is cooked and the time when the heat is started until the heat is started. If the temperature is less than a predetermined temperature, the lid heating means heats the radiator plate, and if the temperature is equal to or higher than the prescribed temperature, lid heating control means for stopping the heating of the radiator plate is provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment 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 inner frame 2, the outer frame 3 and the frame 4 form a container body, and the pot 1 is detachably provided in the inner frame 2.

A heat-sensitive device 5 is provided at the center of the bottom of the inner frame 2, and a rice-cooking heater 6 is arranged 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.

A control unit 8 accommodating a control circuit to be described later is mounted on the bottom of the outer frame 3. 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 radiator plate 10, and a heat shield plate 12 covers the lid heater 11 so that heat from the lid heater 11 does not reach the lid body 9. ing.

A pan bottom sensor 13 is provided inside the heat sensitive device 5, and a pan inside sensor 14 is provided at a portion projecting downward from the center of the lid body 9, and the heat radiating plate 10 and the heat shield are provided. In the vicinity of the lid heater 11 surrounded by the plate 12, a heat radiating plate sensor 15 is provided as a heat sensitive means. Each of these sensors 13, 14 and 15 is a sensor that detects the temperature.

FIG. 2 is a block diagram showing the 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 that 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 unit 28 via the display unit control circuit 27. Through the heater control circuit 29, the microcomputer 21
The heater switch unit 30 for directly energizing the rice cooking heater 6, the warming heater 7, and the lid heater 11 is controlled.

As shown in FIG. 3, the heater switch section 30 has a commercial power source 31, a rice cooker 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 the rice cooking heater 6 is supplied with electric power.

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 less than 115 ° C., then it is determined whether 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 SW32 is turned on by the clock circuit 25.
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 heater 6. At this time, when the pot 1 is in an empty state such as when water is not mixed with rice, when the temperature Tu detected by the radiator plate sensor 15 reaches 115 ° C. The power supply is stopped.

In the normal case, water boils and reaches the equilibrium temperature near 100 ° C., so the temperature Tu detected by the radiator plate sensor 15 has an increase rate of 1 ° C. per 3 minutes.
Below, at that time, heating of the radiator plate 10 is started by the lid heater 11.

The temperature T detected by the pan bottom sensor 13
Until d reaches 120 ° C., the temperature Tu detected by the radiator plate sensor 15 is kept at 200 ° C.
Energization of the lid heater 11 is controlled.

The temperature T detected by the pan bottom sensor 13
When d reaches 120 ° C., the power to the rice cooking heater 6 is stopped. Until 15 minutes have elapsed from that time, the lid heater 11 is energized and controlled so that the temperature Tu detected by the heat dissipation plate sensor 15 is maintained at 200 ° C.

After 15 minutes, as the heat retention control, the heat retention heater 7 is energized so that the temperature Td detected by the pan bottom sensor 13 is maintained at 71 ° C. Also,
In order to prevent the temperature Ti detected by the in-pan sensor 14 from becoming lower than the temperature Td detected by the pan-bottom sensor 13, the temperature Ti detected by the in-pan sensor 14 is further detected by the radiator plate sensor 15. Energization of the lid heater 11 is controlled so that the temperature Tu is maintained at 0.5 ° C. or higher.

As described above, after the rice cooking is started, the heat radiating plate 10 is controlled so as to maintain a predetermined temperature of 200 ° C. from the predetermined time before the heat insulating transition to the start of the heat insulating. Condensation on the
Even if the lid 9 is opened immediately after the transition of heat retention, water drops will not run down.

Also, the sensor 1 inside the pan is kept warm.
Since the temperature of the heat sink 10 detected by the heat sink sensor 15 is controlled to be 0.5 ° C. higher than the temperature of the upper part of the pot 1 detected by No. 4, water droplets adhere to the lower surface of the heat sink 10 even while the temperature is kept warm. Is prevented.

Even if the lid 9 is opened / closed during the heat retention and the temperature of the upper part of the pan suddenly drops, the desired heat retention is immediately returned to by the lid heater 11 so that the heat radiation plate 10 of the lid 9 is covered. There is no danger of water droplets landing.

Further, since the heat radiating plate 10 is used, the heating capacity is small as compared with the conventional method of heating the inner lid, so that a desired temperature can be obtained by heating with low electric power. Heat sink 1
Since the surface of No. 0 is coated with a fluororesin, it is less likely to become dirty and easy to remove. The durability temperature of the fluororesin coat is 250 ° C. or lower, but the temperature of the heat sink 10 is
The temperature is controlled to be equal to or lower than the durability temperature of the resin coat, and therefore the resin coat does not melt and peel off.

Since the heat sink sensor 15 is provided, when the rice is not cooked in the pan 1 or when the pan itself is not set, when the rice is to be cooked empty, the rice is cooked after the rice is cooked. Since the abnormal temperature rise in the pan 1 or the inner frame 2 is detected and the supply of electric power to the rice cooking heater 6 is stopped, it is possible to prevent empty cooking and prevent the lid 9 from being damaged by high heat.

Therefore, there is an effect that the conventional pan switch can be removed. By providing the heat dissipation plate sensor 15 in this manner, it is possible to perform a more versatile sequence than in the past.

[0041]

As described above, according to the present invention,
Provided with a lid heating means for heating the heat dissipation plate and a heat sensitive means for detecting the temperature of the heat dissipation plate, the heat sensitive means sensed from the time when the rice was cooked to the time when the heat retention was started from the predetermined time before the heat retention was started. If the temperature is lower than a predetermined temperature, the lid heating means heats the heat sink, and if the temperature exceeds the predetermined temperature, the heating of the heat sink is stopped.
Condensation on the heat sink can be suppressed before shifting to heat retention to prevent water droplets from running off when the lid is opened, and since the heat sink is not abnormally heated, deformation or discoloration of the lid can be prevented. Can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a circuit configuration of the rice cooker.

FIG. 3 is a circuit diagram of a heater switch portion of the rice cooker.

FIG. 4 is a flow chart of rice cooking control processed by a microcomputer of the rice cooker.

FIG. 5 is a flow chart of heat retention control processed by a microcomputer of the rice cooker.

[Explanation of symbols]

 1 ... pan 6 ... rice cooker 7 ... heat insulation heater 9 ... lid 10 ... radiating plate 11 ... lid heater 13 ... pan bottom sensor 14 ... pan sensor 15 ... radiating plate sensor 21 ... microcomputer 30 ... heater switch part

Claims (1)

[Claims] Claim: What is claimed is: 1. A lid for covering an opening of a pot, a heat radiating plate which constitutes a lower surface of the lid and directly faces the pot, a lid heating means for heating the radiant plate, and a temperature of the heat radiating plate. If the temperature sensed by the heat-sensitive means is less than the predetermined temperature during the period from the start of the heat retention to the heat-sensitive means to start the heat-retention after the rice is cooked, the heat-radiating plate is heated by the lid heating means. A rice cooker comprising: a lid heating control means for heating and stopping heating of the heat sink when the temperature is equal to or higher than a predetermined temperature.