JPS5823311Y2 - electric rice cooker - Google Patents

Description

[Detailed description of the invention] The purpose of the invention is to improve the rice cooking performance of an electric rice cooker.

In general, in order to cook rice well.

It is known that it is best to cook it slowly at first and then slowly in the middle.

In other words, ``Chorochoro'' means that it is necessary to heat the rice slowly over low heat until it reaches about 65°C, when it begins to gelatinize, so that enough water can penetrate into the inside of the rice.

This is because if rapid heating is performed without sufficient water penetrating into the rice, the surface layer of the rice will gelatinize first, and the surface layer of the rice will prevent water and heat from penetrating into the rice. Due to the nature of rice, there is a lack of water and heat necessary for gelatinization inside the rice.
This is because rice with a so-called core is cooked.

In addition, medium pappa means that rice starch is cooked with strong heat after 65℃, when gelatinization begins, to promote gelatinization of rice starch, and to actively generate convection, which prevents uneven cooking in the upper and lower portions. I'm preaching that.

Conventional electric rice cookers heat at a constant wattage regardless of the amount of rice cooked, so their internal temperature characteristics are as shown in solid line 49 in Figure 1.
As shown in the figure, the temperature characteristics change depending on the amount of rice cooked.

A shows the internal temperature characteristics when the amount of rice cooked is small, and 口 shows the internal temperature characteristics when the amount of rice cooked is large.

a and a' indicate the start time of rice cooking, b and b' indicate the start time of gelatinization, C and C' indicate the boiling point, and d and d' indicate the end time of rice cooking.

Moreover, x and x' indicate the time from the start of rice cooking until the gelatinization temperature is reached.

Further, Y indicates the minimum time necessary to fully soak rice with water at a temperature below the gelatinization temperature.

It has been empirically confirmed that this time is usually about 10 minutes.

With conventional rice cookers like this, when the amount of rice to be cooked is small, the time X required for the rice to reach the gelatinization temperature is short, and the rice is cooked without sufficient water permeating inside, resulting in what is known as a cored rice. becomes.

In addition, when the amount of rice to be cooked is large, the above-mentioned required time can be met, but there is a drawback that the rice cooking time becomes longer than necessary.

Furthermore, regarding the wattage after reaching the gelatinization temperature,
Minimum time required for rice starch to gelatinize sufficiently (Z-Y
= about 5 minutes or more), and if you set the power too high and the gelatinization time is too short (see Figure 1), you won't be able to cook delicious rice.

Another disadvantage is that unless the wattage is increased a little, the total cooking time will be longer (see Figure 1, Part 2).

In other words, regarding the wattage while reaching the gelatinization temperature,
It is necessary to cook at the wattage according to the amount of rice cooked, and the first
Experiments have confirmed that cooking rice according to the curve shown in Figure E is the ideal rice cooking method.

From the experimental results, the relationship between the amount of rice cooked and the wattage for ideal rice cooking is as shown in the table below.

The present invention realizes the above-mentioned ideal rice cooking, and will be explained below based on the attached drawings.

In Fig. 2, 1 is an AC power supply, 2 is a non-returnable thermostat that opens upon detecting the completion of rice cooking, 3 is a heater, 4 is a power control device for controlling the amount of electricity supplied to the heater 3, and a capacitor charging circuit. 5, this capacitor charging circuit has a thermoswitch 6 which is opened at a predetermined temperature, and a plurality of first resistors 7 and second resistors 8 connected in series are connected in parallel across both ends of a thermoswitch 6 which is opened at a predetermined temperature. One end of a selection switch 9 is connected to each connection point between the first resistor 7 and the second resistor 8, and the other end is connected to a capacitor 10.

Reference numeral 11 is a low frequency astable multi-circuit that outputs an on/off output according to the charging/discharging cycle of the capacitor 10, and 12 is a switch connected in series to the heater 3, which opens and closes depending on the output thereof.

In the above configuration, when the thermostat 2 is manually closed, power is supplied to the power control device, and when the selection switch 9 corresponding to the amount of rice cooked is closed, the thermoswitch 6 is closed in the first half of the rice cooking because the rice cooking temperature is low. Since the first resistor 7 and the second resistor 8 are connected in parallel and the capacitor 10 is charged through these resistors, the charging time is short, and accordingly, the on-output time of the astable multi-circuit 11 is also shortened. It is short, and the amount of current applied to the heater 3 is reduced.

Therefore, in the first half of rice cooking, rice is cooked at a low power suitable for the amount of rice to be cooked.

Next, in the second half of rice cooking, the rice cooking temperature reaches the gelatinization temperature, so the thermoswitch 6 is opened and the capacitor 10 is
Since only the first resistor 7 is connected, the charging time is long, and accordingly, the on-output time of the astable multi-circuit 11 is also long, and the amount of current supplied to the heater 3 is increased.

Therefore, in the second half of rice cooking, rice is cooked at a high power suitable for the amount of rice cooked.

At this time, there is a part of the current that flows through the other resistor groups and the second resistor, but the first resistance value may be determined by taking these into consideration.

Thereafter, as the rice cooks and the moisture in the rice disappears, thermostat 2 opens and the rice cooking is completed.

A first resistor 7 having a different resistance value depending on the amount of rice cooked is arranged in parallel with the first resistor 7 and the second resistor 8 described above.
A, 7b, 7C and second resistors 8a, 8b, 8c are provided in appropriate numbers, and selection switches 9a, 9b, 9C are provided, respectively.

In addition, in the above embodiment, an example was shown in which the thermoswitch 6 was used to switch the amount of electricity to the heater midway through the process.
Instead of the thermoswitch, control may be performed using a delay switch that operates at a predetermined time.

As described above, according to the present invention, rice is cooked with the first half wattage and second half wattage suitable for the amount of rice to be cooked, so that rice can be cooked along the shark curve shown in the first diagram.

In addition, the combination of resistors that determine the wattage (amount of current) for each can be selected independently using a selection switch depending on the amount of rice cooked, and can be changed from low to high wattage using a single thermo switch or delay switch. It has great practical effects, such as being able to switch, have a simple configuration, and be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing rice cooking temperature characteristics, and FIG. 2 is a circuit diagram of an embodiment of the present invention. 3... Heater, 4... Power control device,
5... Capacitor charging circuit, 6... Thermoswitch, 7, 7 a, 7 b. 7C...First resistor, 8, 8 a, 8 b
, 8 C...Second resistance, 9, 9 a, 9
b, 9 C...selection switch, 11...
...Low frequency astable multi circuit.

Claims (1)

[Scope of utility model registration request] The power control device includes a heater, a selection switch that selects heater power corresponding to the amount of rice cooked, and a power control device that increases the heater power during the cooking process, and the power control device has a capacitor charging and discharging circuit. In this method, a plurality of series-connected first resistors and second resistors are connected in parallel to both ends of a switch that operates at a predetermined temperature or time period, and each connection between the first resistor and the second resistor is connected in parallel. An electric rice cooker in which one end of the selection switch is connected to a point and the other end is connected to a capacitor.