JPS6241005B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-retaining rice cooker for cooking rice and keeping it warm.

In conventional rice cookers that keep warm, the lid heater is
The temperature sensing element controls the energization along with other heaters only when keeping warm, or both when cooking and keeping warm.
Alternatively, electricity was applied continuously regardless of the temperature sensing element only during heat retention.

However, in the former case, even after the rice has been cooked and steamed, the temperature of the rice is higher than the heat retention control temperature, so the temperature sensing element remains open and the lid heater is not energized, resulting in a large amount of rice being left in the lid. There is dew on it, and if you open the lid in such a condensed state, the dew will fall on the food or the floor.

In the latter case, while there is no dew on the lid when steaming is complete, the lid heater is energized regardless of the room temperature or voltage, so the best heat retention is achieved at room temperature and rated voltage. Despite the design, dew from the lid could not be removed well at low temperatures and low voltages, and conversely, the surface of the rice dried out at high temperatures and high voltages.

The present invention was made in view of such circumstances, and
Immediately after the rice is cooked, it will take a certain amount of time (approximately the steaming time)
After energizing the lid heater (for 15 minutes) to remove the dew on the lid, the temperature sensing element turns on the rice cooking heater.
By controlling the electricity supply to all the heaters, including the heat retention heater and the lid heater, all these heaters keep the temperature warm and prevent dew from dripping from the lid when the lid is opened after steaming is completed. By controlling the electricity supply to all heaters, and making the heat generation amount of the lid heater during steaming larger than the heat generation amount of the lid heater during keeping warm, it is possible to quickly and accurately prevent condensation while keeping the temperature warm during keeping warm. To provide a heat-retaining rice cooker that can eliminate dryness and discoloration of the surface of rice and keep the rice well warm.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. FIG. 1 is a cross-sectional view of the main parts of a heat-retaining rice cooker according to the present invention. In the figure, 1 is a main body of the rice cooker, and a top opening of the main body 1 has a lid 2 that covers the opening in an openable and closable manner. has been established.

3 is an inner pot removably housed in the rice cooker main body 1; 4 is an inner lid detachably attached to the lower surface of the lid 2; 5 is an inner bottom of the rice cooker main body 1; specifically, the bottom back surface of the inner pot 3; The rice cooking switch 6 is a rice cooking switch, which is provided through the center of the rice cooking heater 5, and the rice cooking switch 6 senses the temperature rise at the bottom of the inner pot 3. It keeps working off.

Reference numeral 7 denotes a heat-retaining heater provided on the inner surface of the rice cooker main body 1, and a temperature sensing element 8 for heat-retaining control is arranged near the heat-retaining heater 7. Reference numeral 9 denotes a lid heater provided on the lower surface of the lid 2.

Next, the configuration of the electric circuit will be described with reference to FIG.

AC power supply 11, rice cooking heater 5 and rice cooking switch 6
The rice cooking switch 6 is connected to the series circuit of the heat-retaining heater 7 and the temperature-sensing element 8, and the timer 1.
0 are connected in parallel.

Further, the common terminal C of the first contact 10a of the timer 10 and one side of the lid heater 9 are connected, and the lid heater 9
The other terminal is connected to the common terminal C of the second contact 10b of the timer 10.

Furthermore, the normally closed terminal NC and the normally open terminal NO of the first contact 10a of the timer 10 are connected to both ends of the rice cooker heater 5.
Furthermore, the normally closed terminal NC and the normally open terminal NO of the second contact 10b are connected to both ends of the temperature sensing element 8, respectively.

Here, as shown in FIG. 3, the timer 10 includes resistors R1, R2, R3, R4, R5, capacitors C1, C2, diodes D1, voltage regulator diode D2, oscillation circuit 12, frequency dividing circuit 13, inverters 14, 16. , a flip-flop circuit 15, a thyristor 17, and a relay 18.

The present invention is constructed as described above, and its operation will be explained below.

When the rice cooking switch 6 is turned on, power is applied to the rice cooking heater 5. At this time, since no voltage is generated across the rice cooker switch 6,
Neither the heat retention heater 7 nor the lid heater 9 heats up.

When the rice in the inner pot 3 is cooked due to the heat generated by the rice cooking heater 5, the temperature at the bottom of the inner pot 3 rises rapidly, and the rice cooking switch 6 senses this and opens the rice cooker switch 6. As a result, a voltage is generated across the rice cooking switch 6, and the voltage is supplied to the timer 10. As a result, the resistance R
1, R2, diode D1, capacitor C1,
The constant voltage diode D2 generates a DC voltage across the constant voltage diode D2 as shown by d in FIG.
3. It serves as a power source for the inverters 14 and 16 and the flip-flop circuit 15.

As shown by e in FIG. 4, if the time constant of the integrating circuit made up of resistor R3 and capacitor C2 is selected to be sufficiently longer than the time during which voltage is generated across voltage regulator diode D2, power supply current is supplied to frequency dividing circuit 13. Afterwards, a reset is applied, and the output of the frequency dividing circuit 13 starts from "o" (low level) as shown by g in FIG. Further, the output of the flip-flop circuit 15 always starts from "1" (high level) as shown by h in FIG.

Note that the frequency divider circuit 13 is reset when the reset terminal becomes "1" (high level), and the output at that time is "o" (low level).
shall be. As a result, when the rice cooking switch 6 is opened, the thyristor 17 is always conductive, energizing the relay 18, and the first contact 10a and the second contact of the timer 10.
Both of the contacts 10b close C-NO.

Thereby, the lid heater 9 is connected to the AC power source 11, and the heater 9 is energized. At this time, the temperature of the rice is high, so the temperature sensing element 8 is open.
The rice cooking heater 5 and the warming heater 7 are not energized. In this case, if the timer time of the oscillation circuit 12 and frequency divider circuit 13, which oscillates the output waveform shown by f in FIG. 4, is set to the steaming time (approximately 15 minutes), the frequency divider circuit The output of the flip-flop circuit becomes "1" (high level) as shown by g in FIG. h in the figure
Set to "o" (low level) as shown in . Therefore, the thyristor 17 becomes non-conductive, and the relay 18
is de-energized, and the first contact 10a of the timer 10
And the second contact 10b switches to C-NC.
As a result, a circuit in which the rice cooking heater 5 and the temperature sensing element 8 are connected in series to the parallel circuit of the heat retention heater 7 and the lid heater 9 is connected to the AC power supply 11 to form a heat retention circuit.

In this way, the lid heater 9 is made to generate heat only for a certain period of time after rice cooking, that is, until the steaming time has elapsed, to evaporate the dew that adhered to the inner lid 4 during rice cooking, and after that, all heaters 5, 7, 9 This allows you to enter a warm state.

As described in detail above, the present invention includes a rice cooker main body provided with a lid that can be opened and closed, a lid heater provided on the underside of the lid, and a heat-retaining heater provided on the inner surface of the rice cooker main body. A rice cooking heater is arranged at the bottom of an inner pot that is removably housed in the rice cooker body, and when rice is cooked, the rice cooking heater is energized, and the lid heater is energized for a certain period of time immediately after the rice cooking is completed, and then the rice is cooked, kept warm, and heated. Since the structure is such that the entire lid is kept warm by the heater, the lid 2 is heated after steaming is completed.
When the lid 2 is opened, dew can be prevented from dripping from the lid 2, and when keeping warm, all the heaters 5, 7, and 9 are energized by the thermosensor to keep the heat well maintained. be. In addition, the lid heater 9
The circuit is configured in such a way that the amount of heat generated by the rice cooker is larger during the so-called steaming period, which is a certain period of time after the completion of cooking, than when keeping the rice warm.In other words, when steaming, the lid heater 9 is energized with 100 V straightly applied. Therefore, the amount of heat generated by the lid heater 9 is approximately 30% larger than that of the lid heater 9 during heat retention, and dew condensation on the inner lid 4 can be effectively prevented within a very short time. The low calorific value of the rice suppresses drying and discoloration of the surface of the rice, prevents deterioration of the rice due to heat retention, and allows for good heat retention.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of the heat-retaining rice cooker according to the present invention, Fig. 2 is an electric circuit diagram, and Fig. 3 is a timer 1.
FIG. 4 is a waveform diagram of each part in FIG. 3. 1 is the rice cooker body, 2 is the lid, 3 is the inner pot, 5 is the rice cooker, 7 is the heat retention heater, and 9 is the lid heater.

Claims (1)

[Claims] 1. A lid is provided on the rice cooker main body so that it can be opened and closed, and a lid heater is provided on the underside of the lid, while a heat retention heater is provided on the inner surface of the rice cooker main body, and the rice cooker is removably housed in the rice cooker main body. A rice cooking heater is disposed at the bottom of the inner pot, and when rice is cooked, the rice cooking heater is energized, and immediately after the rice cooking is completed, the lid heater is energized for a certain period of time, and then the rice is cooked, kept warm, and kept warm by all the heaters on the lid, The heat-retaining rice cooker has a circuit configuration such that the amount of heat generated by the lid heater alone is larger when electricity is energized for a certain period of time immediately after rice cooking is completed than when the lid heater is kept warm.