JP2890171B2 - Rice cooker control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a rice cooker, and more particularly to a rice cooker control method capable of preventing a so-called premature cut-off of a heating source before the water in a kettle evaporates sufficiently. It is.

[0002]

2. Description of the Related Art A general rice cooker shown in FIG. 4 has a heating source (2) (in which a gas burner is employed).
Temperature sensor attached to the outside bottom of the pot (1) heated by
(S) and a control device (not shown) for controlling the amount of heat generated by the heating source (2) while judging the temperature detected by the temperature sensor (S).

In this apparatus, when the rice cook operation is started by the heat generated by the heating source (2), the water in the cooking pot (1) boils and evaporates gradually, and the temperature sensor is operated while the water is boiling.
The detected temperature of (S) is kept at the boiling temperature. And the kettle (1)
When the water inside the evaporator finishes evaporating and the temperature detected by the temperature sensor (S) rises to the cooking completion temperature (usually 145 ° C) higher than the boiling temperature, the heating source (2) is kept in the heating stopped state and the cooking is completed. State.

[0004] However, in the rice cooking method of cooking rice while judging the temperature of the bottom of the pot as described above, short-grain rice with a high degree of uniformity, called "grain uniformity" (Japonica-type rice widely consumed in Japan). Is rice that can be cooked properly, such as rice that contains a large amount of small-grained rice grains (hereinafter referred to as “floured rice”) such as broken rice grains, or rice that is not evenly distributed, such as Indica rice represented by Thai rice There was a problem that long grain rice could not be cooked properly.

The above problem will be described in more detail. When cooking rice mixed with a lot of powdered rice as described above, small-grained powdered rice is gathered and deposited on the bottom of the pot, and the gap formed at the boundary between rice grains is small at the bottom of the pot. Therefore, it is difficult for water to penetrate into the lower part of the sedimentary layer of these rice grains. This makes it difficult for the heat at the bottom of the pot to convect throughout the pot, and the heat generated by the heating source (2) accumulates at the bottom of the pot. When the rice grains further adhere to each other due to the swelling or gelatinization of the rice grains accompanying the progress of the rice cooking operation, or when a paste-like layer is formed on the bottom of the pot, they act as a heat insulating layer to further form a layer on the bottom of the pot. The heat easily accumulates, and the bottom of the pot detected by the temperature sensor (S) rises to the rice cooking completion temperature even though the water in the pot (1) does not sufficiently evaporate. This allows
(1) The heating source (2) stops generating heat before the water in it completely evaporates, a so-called premature break phenomenon occurs, making it impossible to cook rice properly.

[0006] Further, when cooking relatively elongated rice grains, such as the long-grained rice described above, the long-grained rice tends to line up and deposit laterally on the bottom of the pot, so that the rice grains (R) (R) ) The gap formed between them becomes smaller, and in this case, too, the premature phenomena occurs. In addition, even when rice is cooked with the so-called "Oneva" attached to the bottom of the kettle from the beginning, such as when cooking rice without thoroughly cleaning the inside of the kettle, the "Oneva" inhibits heat diffusion into the kettle. There is a problem similar to the above because it becomes a heat insulating layer. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been described as follows. The temperature sensor (S) monitors the temperature of the bottom of the kettle (1) heated by the heating source (2), and detects the temperature sensor (S). The above heating source until the temperature reaches the cooking completion temperature higher than the boiling temperature
(2) Method of controlling rice cooker to generate heat '', so that the heating source (2) does not prematurely shut off before the water in the kettle (1) evaporates sufficiently to ensure proper rice cooking. That is the task. [Invention of Claim 1]

[0007]

[Technical Means] The technical means of the present invention for solving the above-mentioned problem is described in "Temperature sensor after starting heating of heating source (2)".
(S) The temperature gradient of the detected temperature is determined, and if the temperature gradient is larger than the reference gradient, the control is switched to the control for forcibly generating heat from the heating source (2) for a predetermined rice cooking time. '' It is.

[0008]

The above technical means operates as follows. When rice or the like mixed with powdered rice is cooked, heat easily accumulates in the sedimentary layer of rice grains that have been brought into close contact with the bottom of the pot for the reasons described above, so that the temperature of the pot bottom rapidly rises. As a result, the temperature detected by the temperature sensor (S) for monitoring the bottom temperature of the kettle also rises rapidly, and the temperature gradient becomes larger than the reference gradient. Then, the rice cooking control is switched to a control for forcibly generating heat from the heating source (2) for a predetermined rice cooking time, thereby determining the output of the temperature sensor (S) for which reliability cannot be ensured. No, heating source only for a predetermined cooking time (2)
To complete the rice cooking operation.

When cooking short grain rice with good uniformity, the water in the pot (1) does not boil and convection smoothly during the cooking operation, so that heat does not accumulate at the bottom of the pot. , Temperature sensor (S)
Becomes substantially equal to the reference gradient. Then, in this case, a normal rice cooking operation for causing the heating source (2) to generate heat is performed until the bottom temperature detected by the temperature sensor (S) reaches the rice cooking completion temperature.

[0010]

The present invention has the following specific effects. If the temperature gradient of the bottom temperature detected by the temperature sensor (S) during the rice cooking operation is large, the heating source (2) is forcibly heated for a predetermined time without determining the temperature detected by the temperature sensor (S). Even when rice or the like mixed with powdered rice is cooked, the water evaporates as a whole. Therefore, before the water evaporates sufficiently,
(2) It is possible to avoid the premature stop phenomenon that stops

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a gas circuit (20) to a gas burner (29) as a heating source (2) has a main valve (21) and a proportional valve (2).
2) is inserted and the heater (3) is located at a position surrounding the outer periphery of the kettle (1) heated by the gas burner (29).
A temperature sensor (S) for detecting the internal temperature of the shuttle (1) is attached to the outer bottom surface of the shuttle (1). In addition, pot (1)
The flange portion (13) projecting to the outer periphery of the upper end of the rice cooker (55) is mounted on a rice cooker detection sensor (55) composed of a piezoelectric element. The amount of cooked rice can be determined by measuring the weight.

The temperature sensor (S), the heater (3) and the like are electrically connected to a control circuit (5) incorporating a microcomputer, and the control circuit (5) further includes a rice cooker switch (51). And the thermal insulation switch (52) are connected. The microcomputer in the control circuit (5) stores a control program having the contents shown in the flowchart of FIG. 2, and the operation of the rice cooker of the embodiment will be described below with reference to the figure.

In steps (60) and (61), it is monitored that the warming switch (52) or the rice cooker switch (51) is turned on, and the warming switch is monitored.
When it is confirmed that (52) has been inserted, a heat retaining operation is executed in step (79). That is, the heat retention heater (3) is heated to maintain the cooked rice in the pot (1) at a predetermined temperature. Next, when the rice cooker switch (51) is confirmed to be turned on in the above step (61), the rice amount determination step (62) is executed, and further, the reference gradient (K) or A condition setting step (63) for determining the rice cooking time (L) is executed. The reference gradient
(K) is the temperature over time at which the temperature sensor (S) would detect if it is assumed that the short grain rice of the quantity determined in the rice quantity determination step (62) was cooked with good uniformity. The rice cooking time (L) is the heating time empirically determined as the time required to cook the amount of rice grains determined in the rice quantity determination step (62). Means

The method of determining the amount of cooked rice and the method of determining the reference gradient (K) and the cooking time (L) for each amount of cooked rice will be described in further detail. (621) to (621) to identify the rice cooking capacity (volume of rice grains put in the kettle (1)) calculated based on the size in units of 0.5 liter within a range of 0.5 to 6 liters. 6
24), and then the reference slope (K) according to each rice cooked amount
And steps (631) to (635) for determining the rice cooking time (L).

Next, in step (64), the main valve (21) is opened, and the ignition device (53) disposed near the gas burner (29) is opened.
To burn the gas burner (29),
Start the rice cooking operation. Next, in step (65), the timer
After resetting (T), the detected temperature of the temperature sensor (S) is stored as the initial temperature (A). Then, after waiting for 5 minutes in step (66), the temperature (temperature gradient) in the kettle that has risen during the waiting time is examined. That is, the difference between the temperature of the bottom of the kettle before and after the waiting time of 5 minutes (the detected temperature of the temperature sensor (S) -the initial temperature (A)) is calculated. Then, the temperature difference, that is, the temperature gradient of the temperature detected by the temperature sensor (S) for 5 minutes is compared with the reference gradient (K). Is determined to be in the kettle (1). And in this case, the step (68) is executed, and the rice cooking initial stage (step (65))
The heating of the heating source (2) is continued until the time measured by the timer (T) reset in step S reaches the cooking time (L), and then the main valve (21) is closed to end the cooking operation (step ( 68),
(See (69)).

On the other hand, if the temperature gradient of the temperature detected by the temperature sensor (S) is smaller than the reference gradient (K), the above step (6)
When it is confirmed at the time of the execution of 7), the rice cooking operation is continued while monitoring the temperature of the bottom of the pot (1) with the temperature sensor (S), and the temperature detected by the temperature sensor (S) is 145 ° C., which is the temperature at which the rice is cooked. When it is confirmed that the rice cooking operation has been completed, the determination is made in step (70), and in step (69), the main valve (21) is closed to stop the rice cooking operation. [Invention of claim 2] The invention of claim 2 is the same as the invention of claim 1, but before the water in the kettle (1) evaporates sufficiently, the heating source (2)
It is an object of the present invention to ensure that the rice cookers do not stop early so that appropriate rice can be secured.

[0017]

The technical means of the present invention for solving the above-mentioned problem is as follows: "The temperature detected by the temperature sensor (S), which rises after the heating of the heating source (2) starts, rises to the boiling temperature. Performing a first step of monitoring the temperature,
A second step of measuring the duration of boiling until the detected temperature of (S) starts to further rise from the boiling temperature is executed. If the above duration of boiling is equal to or shorter than the reference boiling time, a predetermined rice cooking time elapses. Until the heat source (2) generates heat. "

[0018]

[Functions and effects] The above technical means have the following functions and effects. When the rice cooking operation starts, a first step of monitoring whether the temperature detected by the temperature sensor (S) rises to the boiling temperature is executed. When the temperature detected by the temperature sensor (S) monitoring the bottom temperature of the pot reaches the boiling temperature, the time during which boiling continues, that is, the temperature detected by the temperature sensor (S) further rises above the boiling temperature. A second step of measuring the time until the start of the operation is performed. Then, when rice containing powdered rice is cooked, the temperature of the temperature sensor (S) is equilibrated with the boiling temperature because the heat at the bottom of the pot is unlikely to diffuse throughout the pot as described above. Continuously rising without temperature or temperature sensor
Even if the detected temperature of (S) is temporarily equilibrated at the boiling temperature, the equilibrium time is shorter than the reference boiling time. Then, in this case, the control is switched to the control for forcibly generating heat from the heating source (2) for a predetermined rice cooking time, thereby determining the output of the temperature sensor (S) for which reliability cannot be ensured. After the heating source (2) is forcibly heated for the cooking time, the cooking operation is terminated. Thus, according to the above technical means, when rice such as powdered rice is cooked,
That is, when the water in the kettle (1) does not boil and convection smoothly, the heating source (2) is forcibly heated for a predetermined time without judging the temperature detected by the temperature sensor (S). Therefore, even when cooking rice or the like containing powdered rice, the water evaporates as a whole, and it is possible to avoid the premature break phenomenon in which the heating source (2) stops before the water evaporates sufficiently.

When cooking short-grain rice having good uniformity without powdered rice, the time required for the detection temperature of the temperature sensor (S) to equilibrate at substantially the boiling temperature, that is, the duration of boiling is as described above. In this case, the normal rice cooking operation proceeds while monitoring the temperature in the pot (1) with the temperature sensor (S).

[0020]

Next, an embodiment of the present invention will be described with reference to the drawings. The schematic structure of the rice cooker is the same as that of FIG. 1, and the microcomputer in the control circuit (5) stores a control program having the contents shown in the flowchart of FIG.

The operation of the rice cooker according to the embodiment will be described below with reference to FIG. As in the embodiment of the first aspect of the present invention, it is monitored that the warming switch (52) and the rice cooking switch (51) are turned on, and the warming operation and the rice cooking are performed in accordance with the operation of these switches (51) and (52). Start the operation. Then, when it is confirmed that the rice cooker switch (51) is turned on, the amount of cooked rice is determined in units of 0.5 liter similarly to the embodiment corresponding to the first aspect of the present invention (see steps (821) to (824)). ), Determine the cooking time (L) according to the amount of cooked rice. Also, when cooking rice with good uniformity without powdered rice mixed with short grain rice of each rice cooked rice amount,
The time during which the inside of the pot (1) in which the rice of each rice amount is put is kept at the boiling temperature, that is, the reference boiling time (M) is stored for each rice amount (see steps (831) to (835)). .

Next, in step (84), the main valve (21) is opened, and the ignition device (53) disposed near the gas burner (29) is opened.
To burn the gas burner (29),
Start the rice cooking operation. In step (85), the timer (T1) is reset, and in step (86), it is monitored that the detected temperature of the temperature sensor (S) rises to the boiling temperature of 100 ° C. Reset the time timer (T2).

In step (88), it is again determined whether or not the temperature detected by the temperature sensor (S) is maintained at the boiling temperature. If the temperature exceeds the boiling temperature, step (89) is executed to execute the boiling time timer ( Compare the output of T2) with the reference boiling time (M) .If the former is shorter, it is considered that rice with powdered rice mixed therein is cooked and the kettle bottom temperature is rapidly increasing. It is monitored that the timer (T1) measured in step (1) resets to the rice cooking time (L) (see step (90)), thereby forcibly executing the rice cooking operation for the rice cooking time (L). That is, in such a case, the rice cooking operation is performed for the rice cooking time (L) without judging the temperature of the bottom of the pot detected by the temperature sensor (S).

On the other hand, when the step (89) is executed, the boiling time measured by the boiling time timer (T2) is equal to the reference boiling time.
(M) In the case above, it is determined that the rice is cooked with normal short grain rice with good uniformity, and in this case, the temperature sensor (S) is continuously monitored in step (91) to check the temperature. After the gas burner (29) is burned until the temperature of the bottom of the pot detected by the sensor (S) reaches 145 ° C., which is the rice cooking completion temperature, the main valve (21) is closed in step (92) to complete the rice cooking operation.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a rice cooker embodying the present invention.

FIG. 2 is a flowchart adopted when implementing the invention of claim 1;

FIG. 3 is a flowchart adopted when implementing the invention of claim 2;

FIG. 4 is an explanatory view of a conventional technique.

[Explanation of symbols]

 (1) ・ ・ ・ Hook (2) ・ ・ ・ Heating source (S) ・ ・ ・ Temperature sensor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) A47J 27/00

Claims (2)

(57) [Claims] A temperature sensor (S) monitors a bottom temperature of a pot (1) heated by a heating source (2), and a temperature at which the temperature detected by the temperature sensor (S) is higher than a boiling temperature. In the control method of the rice cooker in which the heating source (2) is heated until the temperature becomes, the temperature sensor after the heating of the heating source (2) starts.
(S) determining the temperature gradient of the detected temperature, and if the temperature gradient is greater than the reference gradient, switching to a control for forcibly generating heat from the heating source (2) for a predetermined rice cooking time. Control method. A temperature sensor (S) monitors the temperature of the bottom of the pot (1) heated by the heating source (2), and a temperature at which the temperature detected by the temperature sensor (S) is higher than the boiling temperature. In the control method of the rice cooker in which the heating source (2) is caused to generate heat until the temperature becomes, the temperature sensor which rises after the heating source (2) starts heating.
Execute the first step of monitoring that the detected temperature of (S) rises to the boiling temperature, and then measure the duration of boiling until the detected temperature of the temperature sensor (S) starts to further rise from the boiling temperature. The second step is performed, and when the boiling duration is equal to or shorter than the reference boiling time, the control method of the rice cooker is switched to the control for heating the heating source (2) until a predetermined rice cooking time elapses. .