JPH0313488B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to heating cooking utensils, and more specifically, to detecting the temperature of a cooking pot using a temperature sensor, and to detecting the temperature of a cooking pot using a temperature sensor, and also detecting the temperature of a cooking pot using a temperature sensor. The present invention therefore relates to a heating cooking appliance that can stop the supply of gas.

<Prior Art> The above heating cooking appliance is equipped with a temperature sensor made of a thermistor, bimetal, etc. that detects the temperature by contacting the bottom of the pot. Then, the optimal cooking temperature is set according to the cooking content, and the heating power is adjusted based on the cooking temperature. In order to prevent fires, for example, based on the ignition temperature of oil, an automatic extinguishing temperature is set which is a predetermined temperature lower than this ignition temperature in consideration of safety, etc., and the temperature detected by the temperature sensor reaches this automatic extinguishing temperature. Then, a solenoid valve is driven to stop the gas supply to the burner and automatically extinguish the fire (see Japanese Patent Publication No. 60-4734).

<Problems to be Solved by the Invention> Since the heating cooking appliance described above adjusts the heat power based on the cooking temperature, the heat power adjustment is normally controlled by a microcomputer. Furthermore, the microcomputer also determines when the detected temperature has reached the automatic extinguishing temperature and controls the sending of a solenoid valve drive signal to stop gas supply to the burner when the automatic extinguishing temperature is reached. ing.

However, in the above heating cooking appliance, if an abnormal situation occurs in which the microcomputer breaks down during heating over high heat, the heating power cannot be adjusted, so heating over high heat will continue. Therefore, the automatic extinguishing temperature is quickly reached and there is a risk of flames, so it is necessary to stop the gas immediately. However, because the microcomputer was out of order, it was no longer possible to drive the gas opening/closing means, so there was a problem in that the gas could not be automatically shut off.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a heating cooking appliance that can reliably automatically extinguish the fire even when the cooking temperature rises and reaches the automatic extinguishing temperature. target

<Means for Solving the Problems> To achieve the above object, the heating cooking appliance of the present invention is characterized by having at least two electrical means for controlling the drive of the gas opening/closing means. It is something to do.

One of the electrical means may be a microcomputer, and the other one may be a comparison circuit that operates independently of the microcomputer.

<Function> With the heating cooking appliance having the above configuration, when the automatic extinguishing temperature is reached, each electric means controls the drive of the gas opening/closing means and can perform automatic extinguishing. Furthermore, even if one electrical means fails and the automatic extinguishing temperature is reached, the other electrical means operates to drive the gas opening/closing means.
Can be automatically extinguished.

If one of the electrical means described above is performed by a microcomputer, if the microcomputer fails, the fire power adjustment function is stopped and heating continues, so that the automatic extinguishing temperature is quickly reached. Even in that case, the comparison circuit compares the output of the temperature sensor with the reference value corresponding to the automatic extinguishing temperature and detects that the automatic extinguishing temperature has been reached.
Can be automatically extinguished.

<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 cooking appliance of the present invention. The cooking appliance 1 includes a left 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. A thermistor 3 as a temperature sensor that detects the temperature of the bottom 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 heating cooking utensil 1.

On the front of the left stove 2 side above, there is a stove ignition,
An appliance stopper knob 10 for extinguishing fire and adjusting fire power is provided. Further, 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 automatic fire extinguishing system in the cooking appliance of the present invention.

Gas introduction path 26 that guides gas from the gas introduction port 23
communicates with the burner 4 via a safety valve 21.

The safety valve 21 is opened and closed by a coil 27. The coil 27 is connected to the relay switch 31
The thermocouple 30 is connected to the thermocouple 30 via the thermocouple 30. The coil 27 maintains the safety valve 21 in an open state by the electromotive force of the thermocouple 30 heated by the flame of the burner 4.

The relay switch 31 is connected to the relay coils 32 and 3.
3. When the relay coil 32 is energized, the relay switch 31 is opened, and when the relay coil 33 is energized, the relay switch 31 is closed.

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 shows a voltage drop according to the detected temperature, a voltage corresponding to the voltage drop 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 circuit 3
It is input to the comparison terminal 7 as a reference voltage. Therefore, by knowing the digital signal at the time when the output of the comparison circuit 37 changes, the temperature detected by the thermistor 3 can be known.

On the other hand, the other end of the thermistor 3 is input to a comparison circuit 29. Further, a constant bias voltage applied from the battery 39 via the switch 40 is divided by the resistors 28a and 28b and inputted to the comparison terminal of the comparison circuit 29 as a reference voltage. resistance 28
The values of a and 28b are set so that the reference voltage is approximately equal to the voltage appearing at the other end of the thermistor 3 during detection of the automatic extinguishing temperature. Comparison circuit 2
The output of No. 9 is input to the relay coil 32 via the driver 34 as described later.

The automatic extinguishing temperature is, for example, set to a predetermined temperature lower than the ignition temperature in consideration of safety, etc., based on the ignition temperature of oil.

The microcomputer 36 is connected to the relay coil 33 through the driver 35, and the relay coil 33 is supplied with an excitation signal that closes the relay switch 31. Once the excitation signal is supplied, the relay switch 31 remains closed. Further, the microcomputer 36 is connected to the relay coil 32 through the OR circuit 22 and the driver 34. The output of the comparison circuit 29 is also input to the OR circuit 22 . The relay coil 32 is energized when an excitation signal is supplied from the microcomputer 36 or when an excitation signal from the comparator circuit 29 is input, and opens the closed relay switch 31. Since the excitation signal from the microcomputer 36 and comparison circuit 29 is not supplied to the relay coil 32 when the automatic extinguishing temperature has not been reached,
Relay coil 32 is not energized and relay switch 31 does not open. However, when the temperature detected by the thermistor 3 reaches the automatic extinguishing temperature, excitation signals are supplied from the microcomputer 36 and comparison circuit 29, so the relay coil 3
2 is energized and the relay switch 31 is opened.

Reference numeral 43 denotes a mode changeover switch, which is linked to the mode changeover knob 8 to set the cooking temperature. A timer 44 sets the extinguishing time in conjunction with the timer knob 9, and sends a predetermined signal to the microcomputer 36 to close the safety valve 21 when the set time elapses. Power is supplied to the microcomputer 36, comparison circuit 29, etc. from a dry cell battery 39 via a switch 40, respectively.

To explain the operation of the above configuration, first, the mode changeover switch 43 is used to set the cooking temperature. Next, when the device stopper knob 10 is pushed and turned, the switch 40 is closed. Along with that,
The safety valve 21 opens and gas is supplied,
An ignition means (not shown) is driven to ignite the burner. The open state of the safety valve 21 is maintained by the electromotive force of the thermocouple 30 heated by the flame.

After ignition, when the temperature of the pot rises due to heating and the temperature detected by the thermistor 3 reaches the automatic extinguishing temperature, the microcomputer 36 detects that the automatic extinguishing temperature has been reached and sends a relay coil excitation signal to the OR circuit 22. to open the relay switch 31. As a result, the current flowing through the coil 27 is immediately cut off, the safety valve 21 is closed, the gas supply is immediately cut off, and automatic extinguishing is performed.

Further, automatic extinguishing is also performed by an excitation signal from the comparator circuit 29. That is, when the temperature detected by the thermistor 3 reaches the automatic extinguishing temperature, the input voltage to the comparison circuit 29 rises above the reference voltage, and a relay coil excitation signal is generated at the output terminal of the comparison circuit 29. This excitation signal is input to the OR circuit 22 and excites the relay coil 32 through the driver 34.

In this way, since the relay coil 32 is excited by any signal using two electrical means, the microcomputer 36 and the comparator circuit 29, even if the microcomputer 36 fails, the comparator circuit 29 does not operate. It is possible to close the safety valve 21, stop the gas supply, and automatically extinguish the fire.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, the microcomputer 36
Instead, it may be configured with circuits each having independent functions, and various other design changes may be made without departing from the gist of the present invention.

<Effects of the Invention> As described above, the present invention has the unique effect that even when the cooking temperature rises and reaches the automatic extinguishing temperature, the gas opening/closing means can be reliably closed and automatic extinguishing can be performed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the heating cooking appliance of the present invention, and FIG. 2 is a block diagram of the automatic fire extinguishing system. 1...Heating cooking utensil, 3...Temperature sensor, 21
. . . Gas opening/closing means, 29 . . . Comparison circuit constituting electric means, 36 . . . Microcomputer constituting electric means.

Claims (1)

[Claims] 1. A temperature sensor for detecting the temperature of the cooking pot is provided,
A heating cooking appliance that automatically stops the supply of gas by driving a gas opening/closing means when the detected temperature reaches an automatic extinguishing temperature, comprising at least two electrical means for controlling the driving of the gas opening/closing means. A heating cooking utensil characterized by: 2. The heating cooking appliance according to claim 1, wherein one of the electrical means is a microcomputer and the other is a comparison circuit that operates independently of the microcomputer.