JPH0126331Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rice cooker, particularly a large oven-type rice cooker for commercial use.

In this type of rice cooker, the automatic fire extinguishing device (or automatic rice cooking device) consists of a thermostat, thermistor, etc. that comes into contact with the bottom of the rice cooker to detect its temperature, and a main gas circuit that is activated by signal input from the bottom of the rice cooker. It consists of a solenoid valve inserted into the heater or a main switch inserted into the electric circuit to the heater, and the thermostat etc. detects the temperature when rice cooking is completed, and the solenoid valve is shut off or the main switch is turned off to automatically extinguish the fire. It is.

Further, the empty chamber housing the rice cooker is an oven-type pot chamber having a door on the front and an exhaust hole on the rear wall.

In this case, the heat capacity of the wall portion constituting the pot chamber, the support base that supports the rice cooking pot, and the heat source portion such as the main burner or heater becomes large. Therefore, for a while after cooking rice,
When these parts are in a high temperature state, even after the rice cooker is pulled out from the pot chamber, the heat-sensitive response device consisting of a thermostat etc. as the detection means is kept in operation due to radiant heat or conduction heat from these high temperature parts. The main switch is OFF or the solenoid valve is closed.

Therefore, even if you try to insert a new rice cooker and start cooking rice immediately after the rice cooking is completed, the operating state of the heat-sensitive device consisting of the thermostat etc. is maintained, and the predetermined rice cooking operation is performed. If the solenoid valve inserted into the main gas circuit does not open or the main switch is left in the OFF position, rice cannot be cooked.

Therefore, when rice is to be cooked anew after rice cooking is completed, a certain waiting time is required after the rice cooker is inserted until the temperature of the heat-sensitive part of the heat-sensitive device, which includes a thermostat, etc., falls.

In this invention, during a certain period of time after the start of rice cooking,
Regardless of whether the temperature of the heat-sensitive part of the heat-sensitive device drops or not, the heat source parts such as the main burner and heater are forced to operate, thereby eliminating the waiting time during continuous rice cooking. purpose.

The technical means of the present invention to solve the above problems is to
OR with the output contact of the timer that starts when ON
The output of the circuit is input to the heat source device as an activation signal, and the output contact of the timer is opened after the set time of the timer has elapsed after the operation switch is closed.

According to the above technical means, the rice cooking operation, that is,
At the initial stage when the operation switch is turned on, the output contact of the timer is in the ON state, so the operation switch is The input signal is input to the heat source device and it operates. Therefore, even when cooking rice immediately after rice cooking is completed, in other words, the output contact of the heat-sensitive device is
Even if it is turned off, the rice cooking will continue due to the heat source device.

In this case, the heat-sensitive part of the heat-sensitive device comes into contact with the bottom of the rice cooker, as in the conventional case.
When rice cooking starts, the heat sensitive part is cooled by the rice cooker, and the heat sensitive response device returns to the non-operating state within a certain period of time. After this recovery, the output contact of the timer is
Therefore, when rice cooking is completed, that is, when the temperature of the rice cooker reaches the set temperature of the heat sensitive response device, the heat sensitive response device is activated, its output contact is turned OFF, and the heat source device is stopped (extinguished). Therefore, there is no inconvenience caused by forcibly closing the electric circuit to the heat source device for a certain period of time from the start of rice cooking.

Hereinafter, details of embodiments of the present invention will be explained based on the drawings.

In the embodiment shown in FIG. 1, the present invention is implemented in a gas rice cooker, and the gas circuit 47 to the main burner 2 corresponding to the heat source device described above has a rice cooking valve that opens and closes the circuit. The main solenoid valve 3 is inserted. Further, a sparker 33 for igniting the main burner 2 is disposed near the combustion part of the main burner 2, and on the outer bottom surface of the rice cooker 1 heated by the main burner 2, A thermistor 52, which functions as a heat-sensitive part of the heat-sensitive response device 5, is brought into contact with it.

Next, the electric circuit will be explained.

From the AC power supply 13, the load drive power supply 14
A power source 15 for the control circuit is drawn out, and the circuit on the side of the power source 14 for the load drive includes a high voltage generator 32 for applying high voltage to the sparker 33 described above and a power source 15 for the main solenoid valve 3. Excitation coils 4 are inserted respectively.

On the other hand, an operation switch 9 is provided in the control circuit 44 that receives electricity from the control circuit power source 15, and the output of the operation switch 9 is connected to a first thyristor connected in series to the sparker timer 54. 55, and the output of the operating switch 9 is connected to the second thyristor 70, which is connected in series to the timer 7 to eliminate waiting time during continuous rice cooking, and the input signal of the operating switch 9. The voltage is also applied to the third thyristor 91 for memorization. Incidentally, the setting time of the timer 7 to eliminate the waiting time during the continuous rice cooking is set to about 1 to 10 minutes.

The above-mentioned sparker timer 54 is composed of a time-limited return type timer, and the circuit of the normally open output contact 56 includes a sparker relay 3.
4 has been inserted.

Next, the above-mentioned timer 7, which is provided to eliminate waiting time during continuous rice cooking, is constructed of a time-limited return type timer similar to the above-mentioned sparker timer 54, and its normally open output contact 72 is The voltage on the low potential side is applied to one input terminal of the OR circuit 60, and is also applied to the normally open output contact 7.
The voltage on the low potential side of No. 2 is applied to a PNP type first transistor 75 via a first differentiating circuit 73, and the first transistor 75 controls the voltage of the second thyristor 70 described above. I am trying to reset it.

Thermistor 52 attached to the outer bottom of the rice cooker 1
The output of the comparator 45 is compared with the voltage of the reference voltage setting circuit 77.
The comparison output of No. 5 is applied to the OR circuit 60 together with the output of the timer 7 described above. In this embodiment, the thermistor 52, the reference voltage setting circuit, and the comparator 45 for comparing their outputs correspond to the thermal response device 5 described as a component of the technical means described above.

Further, the output of the comparator 45 is sent to the second differentiating circuit 7.
4 to a PNP type second transistor 76, and the second transistor 76 resets the third thyristor 91 that stores the above-mentioned input signal of the operating switch 9. It's becoming like that. The output of the third thyristor 91 and the output of the OR circuit 60 are ANDed.
This is applied as an input signal to the circuit 78, and the third transistor 85 is turned on and off by the output of the AND circuit 78. Moreover, the excitation coil 4 for the main solenoid valve 3 is connected to the collector circuit of the third transistor 85.
A relay 30 for the main solenoid valve is inserted to turn it on and off.

Next, the actual use of the rice cooker described above will be explained.

Before the operation switch 9 is turned on and the rice cooking operation is not started, the thermistor 52 attached to the outer bottom of the rice cooker 1 is in a cold state, and the output of the thermistor 52 and the reference voltage setting circuit 77 is The comparator 45 for comparison is in a state where an "H" signal is output.

Therefore, the "H" signal of the comparator 45 is applied to one input terminal of the AND circuit 78 via the OR circuit 60, and when the operating switch 9 is turned on in this state, the third The thyristor 91 is turned on, and its signal is applied to the other input terminal of the AND circuit 78, whereby an "H" signal is output from the AND circuit 78 and the third transistor 85 is energized. It will be done. That is, the main electromagnetic valve relay 30 inserted into the collector circuit of the third transistor 85 is energized and its output contact 63 is closed, the exciting coil 4 is energized and the main electromagnetic valve 3 is opened. Gas is supplied to the main burner 2 by this.

On the other hand, the input signal of the operation switch 9 is applied to the first thyristor 55 which operates the sparker timer 54.
This causes the sparker timer 54 to start operating and its normally open output contact 5 to open.
6 is closed for a certain period of time. That is, normally open output contact 5
The output contact 64 of the main burner 2 is closed, the high voltage generator 32 is operated, and the spark for ignition is continuously fired for a certain period of time from the sparker 33 toward the main burner 2 which is in a gas emitting state.

As a result, the main burner 2 enters the combustion state, and the rice cooking operation then proceeds.

The signal from the operation switch 9 that is turned on at the beginning of the rice cooking operation is also applied to a second thyristor 70 on the side of the timer 7 for waiting time during continuous rice cooking, which will be described later. At the same time as 9 is turned on, the normally open output contact 72 is turned on, and the normally open output contact 72 is closed for the set time of about 1 to 10 minutes as described above.
When the set time has elapsed during rice cooking, that is, before the rice cooking is completed, which will be described later, it returns to the open state.

Now, when the rice cooking operation is nearing the end and the temperature inside the rice cooker 1 reaches the rice cooking completion temperature (usually 145℃),
The output of the comparator 45 that monitors the output of the thermistor 52 changes from "H" to "L".

Then, the "L" signal of the comparator 45 and the voltage "L" on the low potential side of the normally open output contact 72 in the open state are input to the OR circuit 60, and the OR circuit 60 The output drops from "H" to "L".

When the output of the OR circuit 60 becomes "L", the AND circuit 78 to which the signal is applied also becomes "L".
A signal is issued, and the third transistor 85, which is operated by the signal, is turned off. That is, the main solenoid valve relay 30 inserted into the collector circuit of the third transistor 85 is deenergized, and its output contact 63 is opened to demagnetize the excitation coil 4 for the main solenoid valve 3. Then, the main solenoid valve 3 closes, the main burner 2 goes into the extinguished state, and the rice cooking operation is completed. Incidentally, when the rice cooking operation approaches completion and the output signal of the comparator 45 drops from "H" to "L", this signal is transferred to the second differentiating circuit 7.
4 is detected, and the second transistor 76 is temporarily turned on by the detection signal. That is, the third thyristor 91, which stores the input signal of the operating switch 9, is reset.

Next, a case will be described in which rice is cooked again immediately after the rice cooking operation is completed, when the heat near the main burner 2 and the thermistor 52 has not yet cooled down.

When rice is re-cooked immediately after the rice cooking is completed, the main burner 2 and the thermistor 52 are in a high temperature state where they are still hot, and the comparator 45 outputs a rice-cooking completion signal, that is, an "L" signal. It has become a state of being.

In this state, when the operation switch 9 is turned on to perform a rice cooking operation, the input signal is applied to the first thyristor 55 belonging to the sparker timer 54, and the sparkler is activated as in the first rice cooking operation described above. Ignition sparks are fired from 33. Further, the input signal of the operation switch 9 is the third one.
The state becomes stored in the thyristor 91.

Further, the input signal of the operation switch 9 is also applied to the second thyristor 70 belonging to the timer 7 for waiting time countermeasures, turning it on, thereby energizing the timer 7 and keeping it normally open. The output contact 72 is closed for a certain period of time (about 1 to 10 minutes). Therefore, the output "H" signal taken out from the low potential side of the normally open output contact 72 is passed through the OR circuit 60 together with the output of the third thyristor 91 that stores the input signal of the operation switch 9. 78, and the AND circuit 78 outputs an "H" signal. That is, the main solenoid valve relay 30 is energized. Thereafter, the same operation as the first operation described above will proceed, the main burner 2 will burn, and the rice cooking operation will proceed. In this way, in the above-mentioned embodiment, even if the vicinity of the thermistor 52 is hot immediately after the end of rice cooking, rice can be re-cooked immediately.

As the rice cooking operation progresses, the vicinity of the thermistor 52 is naturally cooled, and the output of the comparator 45 returns from "L" to "H", and after this return, the normally open output contact of the timer 7 72 will open.

In this state, the same operation as the first rice cooking operation described above proceeds.

In the above embodiment, the present invention is applied to a gas rice cooker, but when the present invention is applied to an electric rice cooker shown in FIG. At the same time, the heater relay 35 is inserted into the collector circuit of the third transistor 85 described above, thereby turning the electric heater 11 on and off. In this case, it goes without saying that the sparker relay 34, the associated sparker timer 54, the first thyristor 55, etc. in the first embodiment become unnecessary. Further, in this second embodiment, the third transistor 85 and the heater relay 35 correspond to the main switch described as a component of the technical means described above.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, and Fig. 2 is an explanatory diagram of another embodiment. Response device, 6... Output contact, 7
...Timer, 8...Output contact, 9...Operation switch.

Claims (1)

[Scope of utility model registration request] In a type of device in which the heat-sensitive part of the heat-sensitive device is brought into contact with the bottom of the rice cooker, and the output signal of the heat-sensitive device closes the rice cooking valve or turns off the main switch, the output contact of the heat-sensitive device and Connection with the output contact of the timer that starts when the operation switch is turned on.
The rice cooker is configured such that the output of the OR circuit is inputted to the heat source device as an activation signal, and the output contact of the timer is opened after the set time of the timer has elapsed after the operation switch is closed.