JPS5917317A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rice cooker that cooks delicious and easily digestible rice.

When humans eat rice as food, they must soak the rice in water and heat it to convert indigestible beta starch into easily digestible alpha starch. At this time, it is desirable not only to simply convert β starch into α starch, but also to cook the rice into delicious rice.

The rice, which has absorbed enough water, is placed in the pot for about 20 minutes at a temperature of about 100°C, as shown in the rice cooking temperature characteristics shown in Figure 1.
It is said that it is important to heat the rice for a minute to ensure that the α-starchization of the rice is sufficiently carried out.

By the way, existing rice cookers apply constant electric power to the rice cooking heater 3 provided at the bottom of the inner pot 2 housed in the rice cooker body 1, as shown in Fig. 2, regardless of the amount of rice cooked. , a certain constant temperature P (approximately 140
When 'a) is reached, the rice cooking switch 4 having the non-returnable thermoswitch 4A turns off the electricity to the rice cooking heater 3. Therefore, due to the difference in the amount of rice cooked,
The rice cooking condition of heating at a temperature of about 100°C for about 20 minutes could not be satisfied, and furthermore, after the rice cooking switch 4 was turned off, the rice temperature (temperature in the inner pot 2) suddenly dropped, causing the rice to dry. There are problems such as α-starchization stops, moisture adheres to the surface of the rice, making the rice sticky, and the rice becomes burnt because the temperature at which the rice cooker switch 4 is turned off is about 140'0. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rice cooker that solves the above-mentioned problems and cooks delicious rice that does not cause excess water to adhere to the surface of the rice or burn the rice. (°' The features of the present invention include, in a rice cooker having a means for detecting a rice cooking temperature, a timer for maintaining the rice cooking temperature at which α starch is formed for a predetermined period of time, and an output of the rice cooking temperature detecting means reaching a predetermined value. The present invention is further provided with means for starting the timer means when the timer reaches 1.

Hereinafter, the present invention will be described in detail along with examples.

In all the figures related to the embodiment, parts having the same functions as those in FIG. 2 are given the same symbols, and their explanations will be omitted.

FIG. 4 is a block diagram showing an outline of an electric rice cooker according to an embodiment of the present invention, and FIG. 4(B) is a block diagram of the main parts of FIG. 4(A). In Fig. 4 (A), 11 is the inner pot 2
This is a detection unit that detects temperature changes in the inner pot 2 provided at the bottom of the pot. The detection unit 11, as shown in FIG. 4(B)K,
Temperature sensitive resistance element 11A such as a thermistor and the temperature sensitive resistance element 1
The tube 11C covering the lead wire 11B connecting 1A is housed in the case 11D, and the lid + IE
It is closed by This case 111) is powered by a spring 11G provided in the outer case 11F.
It is pressed with moderate elasticity against the bottom of the. Reference numeral 12 denotes a control section that controls a power switch, timer, etc. in accordance with the output signal of the detection section 11, and reference numeral 16 indicates an operation section that operates the power switch, timer, etc. in the control section 12.

FIG. 5 is a diagram showing a specific electric circuit configuration of the embodiment shown in FIG. 4. In FIG. 5, SWl and SW2 are power ON/OFF switches provided in the operation section 16, 00M1 to C0M3 are comparators, and T r++ T.
ry is a transistor, 1 is a relay contact, 211. is a relay coil. C.I.

C7 is a capacitor, D+ is a rectifier, Dt is a constant voltage diode, R1-R11 is a resistor, TH is a thermistor (temperature sensitive resistance element 11A), 14 is an alternating current, 15 is a heat retention control circuit, and 16 is a heat retention heater.

Next, the operation of this embodiment will be explained with reference to FIGS. 1, 4, and 5.

First, set the inner pot 2 containing measured rice and water in the rice cooker main body 1. Turn the power on switch SWI of the operation unit 13 to O.
NK, capacitor Ot is charged and capacitor C
! The terminal voltage of will be close to Vcc. This causes current to be input to the "+" input terminal of comparator C0M3,
Since it is higher than the “-” input terminal, the comparator C0M6
The output is at a high (hereinafter simply referred to as H) level. Note that at this point, the temperature of the inner pot 2 is low, and the detection part 11
The resistance value of the thermistor TH inside is large (see the temperature characteristics of the thermistor TH shown in FIG. 6). As a result, the terminal voltage Va of the thermistors 1 and 11 becomes a low voltage, and this voltage Va is input to the 1+'' input terminal of the comparator OOMI, and its output becomes a low (hereinafter simply referred to as L) level, so the transistor T r+ is in the OFF state, and capacitor C! Charges that are charged to are not discharged. At this time, the comparator C! inputs the terminal voltage Va of the thermistor TH to the 1-'' input terminal. The output of OM2 is at H level. Comparator C0M2 and comparator C! Transistor Tr where the output of OM 3 is manually operated
The base of the rice cooker heater 3 is turned on because an H level voltage is applied thereto, and by exciting the relay coil 2R and closing one relay contact, power is supplied to the rice cooking heater 3 and rice cooking is started.

In addition, to cancel (stop) rice cooking, turn on the power release switch SW2 of the operation unit 13, the charge stored in the capacitor CI is discharged, and the terminal voltage vb decreases, so the "+" of the comparator OOM 3 The input to the ``input terminal'' becomes lower than the input to the ``1-'' input terminal, and the comparator C
The output level of 0M5 becomes L level, and the transistor T
ry becomes OFF state. For this purpose, relay coil 2
R is not excited and the relay contact 1R is in the OFF state, and the power supply to the rice cooking heater 6 can be stopped and rice cooking can be canceled.

As rice cooking progresses, the terminal voltages V and a of the thermistor T I-1 increase in response to the rise in the temperature of the inner pot 2, and the thermistor T
I] is a set temperature T such that the temperature is as shown in FIG.

The resistor R=,
Set using R3, R4 and thermistor TH. In this way, when the thermistor TH reaches the set temperature T1, the output of the comparator 00M1 becomes H level, the transistor T r + turns on, and the capacitor C
The charges charged in the transistor 2 start discharging through the resistor R♂ and the transistor TI. After this, when the temperature of the thermistor T H reaches T on the rice cooking temperature characteristic shown in Figure 1, (here, the "=" input terminal of the comparator 00M2 is connected to the resistor so that it is higher than the "+" input terminal. the law of nature.

R, , R, , are set using the thermistor TH. ) The output of comparator 00M2 becomes L level. In this case, the pace of the transistor Try becomes low, so the transistor Trt is turned off, the relay coil 2R is not excited, and the relay contact 12 is turned off. For this reason, power is not supplied to the rice cooking heater 6, and the temperature of the inner pot 2 decreases.

Then, the terminal voltage Va of the thermistor TH decreases, and the comparator C! Since the "-" input terminal of OM2 becomes lower than the "+" input terminal, its output becomes H again and turns ON, energizing the relay coil 2R, closing the relay contact 1R, and supplying power to the rice cooking heater 3. As this state approaches the set time, the discharge of capacitor C2 progresses, and the terminal voltage vb of capacitor C7 gradually decreases, and when it falls below the voltage at the "-" input terminal of comparator 00MM, the output of comparator 00M3 becomes When the level is low, the base voltage of the transistor T r t decreases and becomes OFF, opening the relay contact 1R and ending the rice cooking.

This comparator C! The time from when OMj reaches 1M'f-1° until the output of comparator 00M3 becomes L level is set to about 20 minutes by the time constant of capacitor C1 and resistor Ra.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without changing the gist thereof. For example, in the embodiment described above, a relay was used to control the rice cooking heater, but a thyristor, tria, relay, etc. may also be used.

As explained above, according to the present invention, rice can be cooked under the optimal conditions of heating at a temperature of about 100°C for about 20 minutes. In other words, it is possible to completely convert the rice into α-starch without lowering the temperature of the rice during cooking, and to make delicious rice with little burntness without allowing excess water to adhere to the surface of the rice. Furthermore, even if the amount of rice cooked changes, the power is controlled according to the amount of change, making it efficient.In addition, unlike conventional rice cookers, there are no levers, and the operation and control parts are compact and easy to store. There are advantages.

[Brief explanation of the drawing]

Figure 1 shows the ideal cooking temperature curve, Figure 2 shows the ideal cooking temperature curve.
FIG. 3 is a diagram showing the rice cooking temperature curve in the conventional electric rice cooker, and FIG. 4 (A) is an outline of an embodiment of the present invention. FIG. 4(B) is a specific configuration diagram of the main parts of FIG. 4(A), and FIG. 5 is a specific electrical circuit configuration diagram of FIG. 4(A), FIG. FIG. 6 is a diagram for explaining the operation of this embodiment. 1 Rice cooker body 2 Inner pot 6 Rice cooking heater 11 Detection section 11A Temperature-sensitive resistance element +IB Lead wire 11Q
Tube 111) Case 11E Lid
11p Exterior case 11Q Spring
12 Control unit 13 Operation unit 14 AC power supply 5
W1-ON switch, CH S W 2- OF F Switch 00MI~00M3 Comparator Tr++ Tr-transistor 1R relay contact 2 relay coils a,, C, capacitor Dl Rectifier D2 Constant voltage diode ■, ~RI+ Resistor T summer] Thermistor substitute Person Patent Attorney Autumn 1) Earnings 1 Figure 3 Figure 2 (#) Figure 2

Claims (1)

[Claims] In a rice cooker having a means for detecting a rice cooking temperature, a timer means for maintaining the rice cooking temperature at which alpha starch is formed for a predetermined period of time, and a means for starting the timer means when the output of the rice cooking temperature detecting means reaches a predetermined value. A rice cooker characterized by being equipped with.