JPH0220900B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a heating rice cooker, and more specifically, the rice cooker is heated by being placed on a gas stove, and the temperature of the rice cooker is controlled by a temperature sensor. The present invention relates to a heating rice cooker that can detect temperature and adjust the heating power for cooking rice.

<Prior Art> When cooking rice, the variable heating power type heating rice cooker continues to heat the rice over high heat until it reaches boiling temperature, and then switches to low heat after boiling. As shown in FIG. 5, the temperature control pattern is such that the temperature drops after switching to low heat, and then gradually recovers to reach a high temperature. The reason why the temperature drops is because cooked rice contains a large amount of water, so it is not possible to maintain the boiling temperature with low heat. After that, as the water evaporates, the weight of the contents of the kettle decreases, and the temperature can rise even with low heat, reaching a high temperature.

<Problems to be Solved by the Invention> However, if the temperature drops even temporarily after switching to low heat, it will interfere with the alpha conversion of the rice, resulting in poor quality of the rice. There is also the problem that the cooking time becomes longer. Therefore, even if the water boils, it is desirable not to immediately switch to low heat, but to continue heating on high heat to maintain the temperature, and switch to low heat after a certain period of time when a predetermined amount of water has evaporated.

However, since the above-mentioned fixed time varies depending on the amount of cooked rice, the amount of cooked rice must be known in advance. Therefore, it is conceivable that the operator measures the amount of cooked rice and sets the above-mentioned fixed time based on the measured amount, but this is cumbersome.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a heating rice cooker which can produce rice well and which requires a short cooking time.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the heating rice cooker of the present invention has _{the following} advantages: a first timer for measuring the time T, a multiplier for multiplying the time T by a constant m, a memory for storing the time mT multiplied by the constant, and a detection means for detecting that the inside of the rice cooker has boiled. and a second timer that measures the passage of time mT from the boiling point, and switches from high heat to low heat after the second timer completes timing.

<Function> With the heating rice cooker having the above configuration, the approximate amount of cooked rice can be estimated by measuring the time T required for the temperature to rise from _θ0 to θ1. Then, the time T is multiplied by an appropriate constant m determined from the evaluation results of the finished cooking, and after boiling, heating is continued with high heat for the time mT to prevent the temperature from decreasing. Note that the constant m cannot be determined to a single value because of the subjective nature of the evaluation of the doneness of cooking, but takes a value within a certain range.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a perspective view showing a heating rice cooker of the present invention. The heating rice cooker 1 includes a left gas stove (hereinafter simply referred to as "stove") 2, a right stove 12, and a grill 11. The left stove 2 consists of a burner 4, a trivet 7 on which the pot is placed, a soup pan 6 placed under the trivet 7, etc., and a thermistor 3 as a temperature sensor for detecting the temperature of the pot is located in the center of the burner 4, and a thermistor 3 is placed on the trivet 7. It is provided so as to protrude slightly from the top surface. A boiling liquid cover ring 5 is fitted around the burner 4 to prevent spilled liquid from entering the inside of the rice cooker.

On the front of the left stove 2 side above, the stove ignition,
An appliance stopper knob 10 for extinguishing fire and adjusting fire power is provided. Furthermore, on the front side, there are also attached a mode switching knob 8 for instructing the optimum cooking temperature according to the cooking content, and a timer knob 9 for setting the time until the fire is extinguished.

In addition, on the front side of the right stove 12, the right stove 12
Also attached are appliance plug knobs 13 and 14 for igniting, extinguishing, and adjusting the firepower of the grill 11.

FIG. 2 is a block diagram of the heating power adjustment system in the heating rice cooker of the present invention.

Gas introduction path 26 that guides gas from the gas introduction port 23
is divided into two paths, a gas introduction path 24 and a gas introduction path 25, both of which communicate with the burner 4. A safety valve 21 is provided in the gas introduction path 26,
Control the entire gas supply. One of the two gas introduction paths 24 is provided with a thermovalve 22 that adjusts high heat and low heat. When the thermovalve 22 is open, gas flows through both inlets 24,
Since it is introduced from 25, it will be a strong fire. When the thermovalve 22 is closed, gas flows through one of the inlet channels 25.
Since the gas is introduced only from the source, the amount of gas supplied is reduced and the heat is low.

The safety valve 21 is automatically closed when the temperature reaches an automatic extinguishing temperature set in advance in case of an abnormal rise in temperature or the like.

The thermovalve 22 has valve coils 28 and 29
driven by. When the valve coil 28 is energized, the thermovalve 22 opens, and the valve coil 29
When energized, the thermovalve 22 closes.

The microcomputer 36 is connected to the valve coil 28 through a driver 41. The valve coil 28 is supplied with an excitation signal that opens the thermovalve 22 when the flame is set to high. It is also connected to a valve coil 29 through a driver 42, and the valve coil 29 is supplied with an excitation signal that closes the thermovalve 22 when reducing the heat to low.

A constant bias voltage is applied to one end of the thermistor 3 from a battery 39 via a switch 40. Since the thermistor 3 produces a voltage drop depending on the detected temperature, a voltage corresponding to the detected temperature appears at the other end of the thermistor 3. This voltage is input to comparator 37. On the other hand, D/A converter 3
A plurality of sweep digital signals are inputted to 8 from the microcomputer 36. and,
The D/A converter 38 outputs an analog signal that changes over a predetermined period and a predetermined amplitude range in accordance with the sweep digital signal, and the comparator 37
is input as a reference voltage to the comparison terminal of Therefore, by knowing the digital signal at the time when the output of the comparator 37 changes, the thermistor 3
The detected temperature can be known.

Reference numeral 43 denotes a mode changeover switch, which is linked to the mode changeover knob 8 to set the rice cooking mode. 44 is a timer switch, which works in conjunction with the timer knob 9 to set the extinguishing time, and when the set time elapses, the safety valve 21 is turned off.
A predetermined signal is sent to the microcomputer 36 to close the .

The timer 30 built into the microcomputer 36 functions as a first timer that measures the time t required for the temperature detected by the thermistor 3 to reach from θ ₀ to θ 1 , and also switches to low heat after boiling. A second timer that measures the time mT until boiling, and a second timer that measures the time t until boiling.
It functions as a third timer that measures the time.

The temperatures θ ₀ and θ1 satisfy θ ₀ <θ1 and are respectively predetermined temperatures before boiling. In this example, θ ₀ =90°C and θ1 = 100°C. The temperature inside the pot is
Normally, the temperature is lower than the temperature detected by the thermistor 3, so even when θ1=100°C is detected, the inside of the pot has not yet reached boiling point. However, under conditions in the mountains where the atmospheric pressure is low and the isoboiling temperature is below 100°C by a certain temperature or more, boiling may have already occurred by the time θ1 = 100°C is detected. Here, we assume normal usage conditions such as on flat land where boiling has not yet begun when θ1 = 100°C is detected.

The microcomputer 36 serving as a calculation means multiplies the time T measured by the timer 30 by m.

Furthermore, the memory 31 built into the microcomputer 36 stores the above-mentioned time mT.

A microcomputer 36 serving as a detection means detects that the inside of the rice cooker has boiled. If the detected temperature is 100° C. or higher and the detected temperature does not rise by 1° C. during the above-mentioned time T, boiling is determined.

Note that the timer 30 may be constituted by separate timers having each of the above functions.

To explain the operation of the above configuration, first, the mode changeover switch 43 is set to rice cooking mode. Next, when the appliance plug knob 10 is pushed and turned, the switch 40 is closed and power is supplied from the dry battery 39 to the microcomputer 36, thermistor 3, etc. At the same time, the safety valve 21 is opened to supply gas, and the ignition means (not shown) is driven to ignite the burner 4.

Figure 3 is a flowchart for adjusting firepower.
Since the rice is in cooking mode, it is necessary to heat the rice with high heat at first, so in step A of FIG. 3, the valve coil 28 is energized, the thermovalve 22 is opened, and the heat is set to high heat. The temperature of the pot increases, and when it is determined in step that the temperature detected by the thermistor 3 has reached θ ₀ =90°C, the timer 3 is started in step.
Operate 0. Thereafter, in a step, when it is determined that the temperature detected by the thermistor 3 has reached θ1=100° C., the timer 30 is stopped in a step.

Next, in step, the microcomputer 36 serving as a calculation means multiplies the time T measured by the timer 30 by m. The time mT is stored in the memory 31 in steps.

In a further step, the microcomputer 36 as a detection means determines the point of boiling based on the aforementioned criteria. FIG. 3B is a flowchart illustrating the steps in detail. First, in the step, it is determined that the detected temperature is 100° C. or higher. If it is 100°C or higher, the current detected temperature is set as φ in step. Then, a timer 30 is started in step. In the step, it is determined whether the timer time t is longer than the time T, and if it is longer, it is determined that there is a breakdown, and the process proceeds to the step.
If it is shorter, the process moves to step and it is determined whether the temperature has increased by 1° C. compared to the temperature φ detected in step.
If the temperature has risen by 1°C or more, return to step. 1
If the temperature has not increased, return to step.

In the step, a timer 30 is started. When it is determined in step that the time measured by the timer 30 has reached mT, the valve coil 29 is energized in step, and the thermovalve 22 is
Close and switch to low heat to reduce heat.

FIG. 4 is a graph showing the time course of the temperature detected by the thermistor after ignition. According to the procedure described above, heating is continued at high heat without reducing the amount of heat until time mT has elapsed after boiling, so the temperature drop is delayed by the time equivalent to mT. Therefore, the boiling temperature can be maintained for the time mT, resulting in better quality rice.

The results of evaluating the cooked rice by changing the value of m using the heating rice cooker of this example are as follows: m=
In the case of No. 2, there was no core, but the surrounding area was a little sticky, and the cooking was slightly uneven. If m=4,
It was evenly cooked and fluffy. When m = 6, the boiling time is longer, so there is a lot of boiling over.
It became a little hard. If m<2, m>6, m
= 2, m = 6, the problem of poor cooking became more noticeable.

From the above results, the best evaluation was obtained when m = 4, so it is most preferable to set m to 4, and m can be set within the range of 2 to 6 depending on the preference for cooked rice. I found out what I should do.

<Effects of the Invention> As described above, according to the present invention, the switching time mT to low heat can be set according to the amount of cooked rice. After boiling, heating is continued with high heat for a period of time mT, so the boiling temperature can be maintained without causing a drop in temperature during this period, and the rice will have a good finish and the cooking time can be shortened. It has the unique effect of being able to.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the heating rice cooker of the present invention, Fig. 2 is a block diagram of the heating power adjustment system, Fig. 3 is a flowchart of the heating power adjustment, Fig. 4 is a graph showing the change in rice cooking temperature over time, and Fig. 5 The figure is a graph showing the change in rice cooking temperature over time in a conventional example. 1...Heating rice cooker, 2...Gas stove, 3...
...temperature sensor, 30...first timer, second timer, 31...memory, 36...microcomputer constituting multiplication means and detection means.

Claims (1)

[Claims of Claims] 1. A heating rice cooker that heats a rice pot by placing it on a gas stove, detects the temperature by bringing the bottom of the pot into contact with a temperature sensor, and then switches the heating power from high heat to low heat to cook rice. a first timer that measures the time T required for the temperature detected by the temperature sensor to rise from a predetermined temperature θ ₀ before boiling to θ ₁ ;
a multiplier for multiplying the time T by a constant m; a memory for storing the time mT multiplied by the constant; a detection means for detecting boiling in the kettle; A heating rice cooker characterized in that the heat is switched from high heat to low heat after the second timer completes timing. 2. The heating rice cooker according to claim 1, wherein the predetermined temperature θ ₀ is 90°C, θ1 is 100°C, and the constant m is 2 to 6. 3. The heating rice cooker according to claim 2, wherein the constant m is 4.