JP2634016B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device such as a gas stove.

[0002]

2. Description of the Related Art For example, a gas stove is provided with a control circuit including a temperature detecting circuit for detecting a heating temperature of a cooking object to be heated, a combustion detecting circuit for detecting combustion / misfire of a burner, and the like. The solenoid valve provided in the gas supply path to the burner is configured by a transistor or the like when the heating temperature detected by the heater becomes abnormally high or when the combustion detection circuit detects misfire or misfire of the burner. 2. Description of the Related Art There is known an apparatus in which gas is supplied to a burner by shutting off via a solenoid valve driving circuit, thereby extinguishing the burner.

[0003] In this type of gas stove,
It is also generally known that a battery is used as a power supply for the control circuit.In such a gas stove that uses a battery as a power supply, a low-current type solenoid valve with low power consumption is used. Although it is possible to hold the valve open even with a small current, when the battery voltage drops to some extent, the operation of the control circuit becomes unstable, and there is a possibility that the closing drive of the solenoid valve may not be performed properly. Therefore, the battery voltage is detected and monitored by a battery voltage monitoring circuit connected to the battery, and when the battery voltage falls to a predetermined value, the solenoid valve is closed and driven via a solenoid valve driving circuit. However, there is known an apparatus in which the gas supply to the burner is shut off to extinguish the fire. In this case, the battery voltage monitoring circuit includes:
Normally, it is started using a battery as a power supply, as in the case of the control circuit.

However, in such a gas stove, the battery voltage is monitored by a single battery voltage monitoring circuit. Therefore, if the battery voltage monitoring circuit fails, the solenoid valve is activated in response to a decrease in the battery voltage. There was an inconvenience that the closing drive could not be performed.

Further, this type of gas stove is provided with a sparker for ignition, and as a power source for the sparker, one using a battery common to the control circuit and the battery voltage monitoring circuit is known. In a gas stove, when the battery voltage is detected and monitored by the battery voltage monitoring circuit using the battery as a power source as described above, and the solenoid valve is driven to close in response to the decrease in the battery voltage, the following inconveniences occur. there were.

That is, while the sparker is driven only during the ignition operation, it generally consumes a large amount of power. Therefore, during the ignition operation, the voltage of the battery that supplies power to the sparker temporarily drops, Even temporarily, the battery voltage may drop to a voltage at which the operation of the battery voltage monitoring circuit becomes unstable.

For this reason, in the prior art, there is a problem that the operation of the battery voltage monitoring circuit becomes unstable even temporarily, and there is a possibility that the closing operation of the solenoid valve may not be performed. .

In this case, in order to solve such inconvenience, for example, it is conceivable to supply power from a dedicated battery to the battery voltage monitoring circuit. However, in this case, a large number of batteries are required and cost is reduced. Disadvantageous.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and has solved the above-mentioned inconvenience. In a combustion apparatus such as a gas stove provided with a sparker and a battery voltage monitoring circuit using a battery as a power source, a fuel supply path to a combustion section is provided. It is an object of the present invention to provide a combustion device which can surely close the solenoid valve provided in the apparatus according to a decrease in battery voltage.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention controls the operation of the combustion section by using an open / close solenoid valve provided in a fuel supply passage for supplying fuel to the combustion section and a battery as a power supply. A sparker that ignites the combustion section using the battery as a power source, and detects a voltage of the battery using the battery as a power source.
A battery voltage monitoring circuit that outputs a signal for closing the solenoid valve when the voltage falls below a predetermined value, and a solenoid valve drive that closes the solenoid valve in response to the output of the signal for closing the battery voltage monitoring circuit Circuit, the voltage of the battery is detected using the battery as a power supply, and when the detected battery voltage becomes equal to or less than a second predetermined value that is equal to or less than the first predetermined value, the solenoid valve is opened. A second battery voltage monitoring circuit that outputs a closing drive signal to the solenoid valve driving circuit; and a limit value of an operable battery voltage of the second battery voltage monitoring circuit is determined by the first battery voltage monitoring circuit. It is characterized by being lower than the limit value.

[0011]

Further, the solenoid valve is an electromagnetic valve which is driven to open by energizing a solenoid and closed by shutting off the energization, wherein the solenoid valve driving circuit comprises a switching transistor connected to the solenoid. Has,
When the battery voltage becomes equal to or lower than a third predetermined value lower than the second predetermined value, a transistor cutoff circuit that applies a voltage for shutting off the switching transistor to the base of the switching transistor is provided at the base of the switching transistor. It is characterized by being connected.

Further, the transistor cutoff circuit is constituted by a pair of divided resistors for dividing and applying the battery voltage to the base of the switching transistor, and the resistance value of each divided resistor is such that the battery voltage is equal to the third voltage. When the voltage falls below a predetermined value, the switching transistor is set to apply a voltage for shutting off the switching transistor to the base of the switching transistor.

[0014]

According to the present invention, basically, when the battery voltage drops below the first predetermined value, a signal for closing the solenoid valve is output from the first battery voltage monitoring circuit,
In response to this, the solenoid valve is driven to close by the solenoid valve drive circuit. Even if the first battery voltage monitoring circuit fails, if the battery voltage drops below the second predetermined value, a signal for closing the solenoid valve is output from the second battery voltage monitoring circuit. Thereby, the solenoid valve is driven to be closed by the solenoid valve driving circuit.

At this time, since the power consumption of the sparker is relatively large, when the sparker operates (when the combustion section is ignited)
In addition, the battery voltage may drop to a voltage at which the operation of the first battery voltage monitoring circuit becomes unstable, for example.
However, in this case, the limit value of the operable battery voltage of the second battery voltage monitoring circuit is lower than the limit value of the first battery voltage monitoring circuit. Even if the battery voltage drops to a voltage at which the operation of the first battery voltage monitoring circuit becomes unstable, as long as the battery voltage is a voltage at which the second battery voltage monitoring circuit is operable, the battery voltage remains at the second level. Falls below a predetermined value, a signal for closing the solenoid valve is output from the second battery voltage monitoring circuit, whereby the solenoid valve is driven to be closed by the solenoid valve driving circuit.

Further, the solenoid valve is an electromagnetic valve which is driven to open by energizing a solenoid and closed by shutting off the energization, wherein the solenoid valve driving circuit comprises a switching transistor connected to the solenoid. If the first and second battery voltage monitoring circuits fail or become inoperable due to an extremely low battery voltage, the battery voltage remains at the third predetermined value. When the following occurs, the transistor cutoff circuit applies a voltage to the base of the switching transistor so as to shut off the switching transistor, thereby turning off the transistor. As a result, the power supply to the solenoid is cut off and the solenoid valve is closed. Driven.

In this case, when the transistor cutoff circuit is constituted by the pair of divided resistors, the structure can be extremely simplified.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory system configuration diagram of the combustion device of the present embodiment, and FIG. 2 is a circuit configuration diagram of a main part of the combustion device of FIG.

In FIG. 1 and FIG. 2, the combustion apparatus of this embodiment is, for example, a gas stove, and a burner 1 as a combustion section.
Supply path 2 (fuel supply path) for supplying gas (fuel) to the tank
An opening / closing solenoid valve 3 and a gas amount adjusting valve 4 for adjusting the gas supply amount are provided. In this case, the solenoid valve 3
In conjunction with the ignition operation of the ignition / extinguishing button 12 for performing the ignition / extinguishing operation of the burner 1, the valve is opened mechanically against a spring (not shown) in response to the ignition operation of a spring (not shown). Is maintained, and the motor is closed when the current is cut off. Further, the opening of the gas amount adjusting valve 4 is adjusted by, for example, an operation of an operation element 6 connected thereto.

The gas stove according to the present embodiment includes a control unit 7 composed of various electronic circuits described later. The control unit 7 includes a solenoid 5 of the solenoid valve 3.
A temperature detector 8 provided at a central portion of the burner 1 for detecting a heating temperature of a food to be heated, and a combustion detector provided near the burner 1 for detecting combustion / misfire of the burner 1 9, a sparker 11 for generating a spark discharge on an ignition electrode 10 provided in the vicinity of the burner 1, and the ignition / extinguishing button 1
2 is connected to a micro switch 18 that opens and closes by the operation of 2, and a sparker switch 11a that is closed by an ON operation (ignition operation) of the ignition / extinguishing button 12.

In this case, the control unit 7 is activated via the microswitch 18 using the battery 13 (shown in FIG. 2) as a power source. 13 voltage state) to the user.

The sparker 11 is an ignition / extinguishing button 1
The sparker switch 1 which is closed by the ON operation of 2
It is driven by a battery 13 via 1a. Then, the ignition / extinguishing button 12 after the burner 1 is ignited
By releasing the ON operation of, the sparker switch 1
1a is opened, the sparker 11 becomes inactive, and the burner 1
The unnecessary operation of the sparker 11 during the ignition is stopped. The opening and closing of the sparker switch 11a is controlled using a heart cam mechanism, for example, as disclosed by the present applicant in Japanese Patent Publication No. 1-59498. In addition, Sparker 11
May be stopped using, for example, a timer started by turning on the ignition / extinguishing button 12.

The temperature detector 8 has a built-in thermistor 15 (shown in FIG. 2) as a temperature sensor, and is used when a cooking pot or the like containing cooked food is placed on the burner 1. At this time, a signal corresponding to the heating temperature of the cooking pot or the like is output from the thermistor 15 to the control unit 7 at this time.

The combustion detector 9 has a built-in thermocouple 16 (shown in FIG. 2) as a combustion detection sensor, and outputs a signal corresponding to the calorific value of the burner 1 from the thermocouple 16 to the control unit 7. Output to

The control unit 7 is activated by the battery 13 via the microswitch 18 which is closed in conjunction with the ON operation of the ignition / extinguishing button 12. Then, the solenoid valve 3 is driven to open to supply gas to the burner 1. At this time, as described above, the sparker 11 is driven by the battery 13 via the sparker switch 11a which is closed by the ON operation (push operation) of the ignition / extinguishing button 12, and generates a spark discharge in the ignition electrode 10. Thereby, the burner 1 is ignited.

As will be described later in detail, the control unit 7 detects the combustion / misfire of the burner 1 based on the output signal of the thermocouple 16 and also controls the heating temperature of the food by the burner 1 and the disconnection of the thermistor 15. Failure of the thermistor 1
5 is detected by the output signal of the thermocouple 1 and the misfire of the burner 1 is detected by the thermocouple 1
6, when the heating temperature of the food detected through the thermistor 15 is higher than a predetermined reference temperature, or when the disconnection of the thermistor 15 is detected. The solenoid valve 3 is driven to close via the solenoid 5.

Further, the control unit 7 monitors the voltage of the battery 13 and, when the voltage drops to a predetermined reference voltage, drives the LED lamp 14 or switches the solenoid valve 3 through the solenoid 5. The drive is closed.

Next, the main circuit configuration of the control unit 7 will be described in detail with reference to FIG.

Referring to FIG. 2, the control unit 7 includes:
A control circuit 1 for controlling the opening and closing of the solenoid valve 3 as described above
7 (the details will be described later).
Operates with the battery 13 as a power supply, while a power supply voltage at which the battery 13 can operate normally is determined. If the power supply voltage falls below the operable limit voltage, normal operation cannot be expected. Therefore, when the output voltage of the battery 13 is reduced to some extent due to the consumption of the battery 13, the control circuit 17 may not operate normally, and the opening and closing control of the solenoid valve 3 may not be normally performed.

Therefore, in this embodiment, the control unit 7 monitors the voltage of the battery 13 successively when the gas stove operates, and when the voltage drops to some extent, notifies the user by the LED lamp 14 to that effect. Shime, or
The solenoid valve 3 is driven to close.

The configuration relating to the monitoring and control of the voltage of the battery 13 will be described below.

The battery 13 includes the ignition / extinguishing button 12
A micro switch 18 that is turned on / off in conjunction with the micro switch 18 is connected, and a battery voltage V _D generated at a point P at the subsequent stage of the micro switch 18 is supplied to the control circuit 17 as its power supply voltage. Incidentally, the battery voltage V _D is also supplied to the sparker 11 via the scan parka switch 11a.

Further, at the subsequent stage of the microswitch 18,
Regulator 19 which generates a constant voltage as an input the battery voltage V _D is connected, the output voltage V of the regulator 19
_R (hereinafter, referred to as a regulator voltage V _R ) is supplied as a voltage for generating a reference voltage in a comparator (details will be described later) included in the control circuit 17.

On the other hand, the control unit 7 of the present embodiment comprises comparators 20 and 21 for comparing the battery voltage V _D with a predetermined judgment voltage, respectively, and blinking for driving the LED lamp 14 according to the output of the comparator 20. Drive circuit 2
2 and the LED lamp 1 according to the output of the comparator 21
4 and a capacitor 25 connected to the point P via a resistor 24 to detect the battery voltage V _{D. When} the battery voltage V _D becomes lower than a predetermined value, the battery voltage V _D is detected. Drive signal (low level signal) for the solenoid valve 3
And a battery voltage monitoring circuit 26 that outputs the same.

Here, in the present embodiment, the comparator 21 composes a first battery voltage monitoring circuit 27 together with a first timer circuit described later, corresponding to the configuration of the present invention. The battery voltage monitoring circuit 26 constitutes a second battery voltage monitoring circuit.

The battery voltage V _D is inputted to each of the comparators 20 and 21 via the dividing resistors 28 and 29 connected to the point P, and the three comparators 20 and 21 are connected to the output side of the regulator 19. Determination voltages of different levels from each other are input via the division resistors 30, 31, and 32. In this embodiment, the rated value, for example, 3V battery voltage V _D at the new state of the battery 13, determines the voltage at the comparator 20 is set to, for example, 2.65V, determination voltage in the comparator 21 is set to, for example, 1.9V Is done. Incidentally, the control circuit 17, until the battery voltage V _D of about 1.9V is the determination voltage of the comparator 21 is lowered is assumed to be operating normally.

Then, each of the comparators 20 and 21
Judgment voltage and battery voltage V _DAnd the
Pond voltage V_DHigh and low binary values according to the magnitude of the judgment voltage
The bell signal is supplied to the blinking drive circuit 22 and the lighting drive, respectively.
The output is output to the driving circuit 23. In this case, flashing
The drive circuit 22 has a battery voltage V_DIs the judgment of the comparator 20
The signal indicating that the voltage has dropped to 2.65 V
When the LED lamp 1 is output from the comparator 20
4 is driven to blink. Lighting drive circuit
23 is the battery voltage V_DIs the judgment voltage of the comparator 21
(1.9 V) is output from the comparator.
The LED lamp 14 is turned on when output from the
The light is driven.

[0038] In this case, the comparator 21, a latch circuit 35 a signal indicating that the battery voltage V _D is lowered to determine the voltage of the comparator 21 (1.9V) retains its output when output from the comparator 21 Is connected.

The output of the comparator 21 is input to a first timer circuit (detailed later) of the control circuit 17 for outputting a drive signal for closing the solenoid valve 3.

Further, the comparator 20, 21 and flashing drive circuit 22, the lighting drive circuit 23, similarly the battery voltage V _D and the control circuit 17 is intended to be the power supply voltage, a determination voltage of the comparator 21 1.9V extent until the battery voltage V _D is decreased is assumed to be operating properly.

The battery voltage monitoring circuit 26 calculates the battery voltage V
_D is the power supply voltage. In this case, the circuit 26 lowers the battery voltage V _D to a voltage (about 1 V in this embodiment) that is lower than 1.9 V, which is the judgment voltage of the comparator 21. Until it can operate normally. Then, the battery voltage monitoring circuit 26, for example, when the battery voltage V _D is of reduced eg to 1.7V, so that outputs to the solenoid valve drive circuit to be described later closing drive signal of the solenoid valve 3.

Next, the configuration of the control circuit 17 will be described in detail.

In FIG. 2, the control circuit 17 comprises a thermocouple circuit 36 for generating a voltage signal in accordance with the calorific value of the burner 1 by the thermocouple 16, and a combustion of the burner 1 by an output signal of the thermocouple circuit 36.・ First and second for detecting misfire
Combustion detecting circuits 37 and 38; a thermistor circuit 39 for generating a voltage signal corresponding to the heating temperature of the food by the thermistor 15; and first and second detecting means for detecting the heating temperature of the food from the output signal of the thermistor circuit 39. (2) a temperature detection circuit 40, 41, a disconnection detection circuit 42 for detecting a disconnection of the thermistor 15 based on an output signal of the thermistor circuit 39, and a signal from the first combustion detection circuit 37 and the first temperature detection circuit 40 to receive the electromagnetic signals. A first timer circuit 43 for outputting an opening / closing drive signal for the valve 3, a second timer circuit 44 for receiving a signal from the disconnection detection circuit 42 and outputting an opening / closing drive signal for the solenoid valve 3, and two switching circuits; Transistor 45,
And a solenoid valve drive circuit 47 having a solenoid valve drive circuit 46.

The first and second combustion detection circuits 37, 38
Have the same configuration, and these detection circuits 37, 38
Is provided with a comparator 49 for comparing the output voltage of the thermocouple circuit 36 according to the calorific value of the burner 1 with a reference voltage for determining combustion / misfire. And these detection circuits 3
7, 38, the comparator 49 compares the output voltage of the thermocouple circuit 36 with a reference voltage for combustion / misfire determination, thereby detecting whether the burner 1 is in a combustion state or a misfire state, and The comparator 49 outputs a high-low binary level voltage signal in response to the detection of misfire. Hereinafter, in the description, a voltage signal having a level corresponding to the combustion state of the burner 1 is referred to as a combustion detection signal, and a voltage signal having a level corresponding to the misfire state of the burner 1 is referred to as a misfire detection signal.

The output of the first combustion detection circuit 37 is input to the first timer circuit 43, and the output of the second combustion detection circuit 38 is input to the disconnection detection circuit 42.

The first and second temperature detecting circuits 40 and 41
Has the same basic configuration, and includes a comparator 50 for comparing the output voltage of the thermistor circuit 39 according to the heating temperature of the food by the burner 1 with a reference voltage corresponding to a reference temperature for determining overheating. ing. Then, these detection circuits 40 and 41 compare the output voltage of the thermistor circuit 39 with the reference voltage for judging overheating by the comparator 50, thereby detecting the level of the heating temperature of the cooking object with respect to the reference temperature, and The comparator 50 outputs a high / low binary level voltage signal in accordance with the level of the temperature. Hereinafter, in the description, a voltage signal of a level corresponding to the case where the heating temperature of the food is higher than the reference temperature is an overheating detection signal, and a voltage signal of a level corresponding to the case where the temperature is lower than the reference temperature is normal heating. It is called a detection signal.

In this case, in this embodiment, the reference temperature for judging overheating of the first temperature detecting circuit 40 and the reference temperature for judging overheating of the second temperature detecting circuit 41 are set to different values. In the first temperature detection circuit 40, for example,
0 ° C. is set as the reference temperature, and the second temperature detection circuit 41 sets, for example, 290 ° C. as the reference temperature.

The output of the first temperature detecting circuit 40 is input to the first timer circuit 43, and the output of the second temperature detecting circuit 41 is input to the base of the transistor 46 of the solenoid valve driving circuit 47. The overheating detection signal and the normal heating detection signal output from the second temperature detection circuit 41 are low-level and high-level signals, respectively. These signals are used to close and close the electromagnetic valve 3 as described later. It is used as a signal and an open drive signal. Further, the overheating detection signal and the normal heating detection signal of the first temperature detection circuit 40 are:
The signal is input to the first timer circuit 43.

The disconnection detecting circuit 42 includes a thermistor 15
And a comparator 51 for comparing the output voltage of the thermistor circuit 39 according to the inter-terminal voltage with a reference voltage for disconnection determination.
By comparing the output voltage of the thermistor 15 with the reference voltage for disconnection determination, it is detected whether or not the thermistor 15 is disconnected. In response to the detection of disconnection / non-disconnection, the comparator 51 outputs a high / low binary level voltage signal. Output. In this case, the output of the second combustion detection circuit 38 is also input to the comparator 51. The comparator 51 determines whether the disconnection of the thermistor 15 has been detected or not. Thus, a voltage signal of the same level is output when a misfire is detected, and otherwise, a voltage signal of another level is output. Hereinafter, a voltage signal having a level corresponding to the disconnection of the thermistor 15 or the misfire of the burner 1 is referred to as a disconnection / misfire detection signal.

The output of the disconnection detecting circuit 42 is input to the second timer circuit 44.

The first timer circuit 43 outputs a misfire detection signal from the first combustion detection circuit 37, outputs an overheat detection signal from the first temperature detection circuit 40, or monitors the battery voltage. constant circuit 53 when the battery voltage V _D from the comparator 21 of use has a capacitor 52 for charging and discharging with a predetermined time constant when the signal indicating that it has been reduced to the determination voltage (1.9V) is output
And a comparator 54 for comparing the voltage of the capacitor 52 with a reference voltage for determining output timing.
The time constant of the time constant circuit 53, the misfire detection signal from the first combustion detection circuit 37 or overheating detection signal from the first temperature detection circuit 40, or the battery voltage V _D of the comparator 21 is 1.9V The voltage of the capacitor 52 is set to a predetermined value when a signal indicating that the voltage has dropped to a predetermined value (in this embodiment, 7 seconds, hereinafter referred to as a timer time) is continuously output.

[0052] Then, the comparator 54 generates an output of the first timer circuit 43, the misfire detection signal or overheating detection signal or the battery voltage V _D is the signal indicating that it has dropped to 1.9V timer, When the output is continuously performed for a time, this is detected by the voltage of the capacitor 52, and a closing drive signal of the solenoid valve 3 is output in response thereto. Is output. In this case, the comparator 54
Is a high / low binary level signal, the closing drive signal of the solenoid valve 3 is at a high level, and the open drive signal is at a low level.

The second timer circuit 44 has the same basic structure as the first timer circuit 43, and includes a time constant circuit 56 having a capacitor 55 and a comparator 57. Then, the second timer circuit 44 includes the first timer circuit 4
Similarly to 3, the disconnection / misfire detection signal from the disconnection detection circuit 42 is a predetermined time determined by the time constant of the time constant circuit 56 (for example, 10 seconds in the present embodiment, hereinafter referred to as a timer time).
When output is continued, the comparator 57 outputs a drive signal for closing the solenoid valve 3, and otherwise, outputs a drive signal for opening the solenoid valve 3. In this case, contrary to the comparator 54 of the first timer circuit 43, the comparator 57 is provided with a polarity such that the closing drive signal of the solenoid valve 3 is at a low level and the open drive signal is at a high level.

The solenoid valve driving circuit 47 supplies the switching transistors 45 and 46 to the solenoid 5 of the solenoid valve 3.
Are connected in series, and transistors 45 and 46 are connected.
When both are in the conductive state (ON state), the solenoid 5
Current is supplied from the battery 13 to maintain the mechanically opened solenoid valve 3 in an open state.
When either one of them becomes a cutoff state (OFF state), the power supply to the solenoid 5 is cut off and the solenoid valve 3 is driven to close.

In this case, the transistor 45 is of a PNP type, and is connected to the timer circuit 43 using the output of the first timer circuit 43 as a base input. As a result, the transistor 45 becomes conductive when the first timer circuit 43 outputs a low-level signal that is the drive signal for opening the solenoid valve 3, and the high-level signal that is the drive signal for closing the solenoid valve 3 is turned on. It is designed to be shut off when output.

On the other hand, the transistor 46 is of an NPN type, and the output of the second timer circuit 44 and the second
The output of the temperature detection circuit 41 and the battery voltage monitoring circuit 26
These circuits 44, 41,
26. Thereby, the transistor 4
6 is turned on when a high-level signal that is an open drive signal for the solenoid valve 3 is output from one of the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 26, When the low-level signal which is the closing drive signal of No. 3 is output, the state is cut off.

In the present embodiment, the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 2
A delay circuit 58 is provided between the output point 6 and the base of the transistor 46 to apply the outputs of these circuits 44, 41, 26 to the base of the transistor 46 with a slight time delay. The delay circuit 58 includes a resistor 59 and a capacitor 60,
The output of the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 26 charges and discharges the capacitor 60 via the resistor 59, and applies the voltage of the capacitor 60 to the base of the transistor 46. . Thus, the outputs of the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 26 are applied to the base of the transistor 46 with a delay of a time constant determined by the resistance value of the resistor 59 and the capacitance of the capacitor 60. You. Therefore,
For example, when the transistor 46 is conducting (the base input is at a high level), the output of any of the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 26 is temporarily changed from the high level to the low level due to noise or the like. In such a case, the momentary low level signal is not applied to the base of the transistor 46,
The conduction state of the transistor 46 is maintained.

In this embodiment, the delay time of the output of the second timer circuit 44, the second temperature detection circuit 41, and the battery voltage monitoring circuit 26 by the delay circuit 58 is set to a sufficiently short value of about several milliseconds. I have.

[0059] When in the present embodiment, the battery voltage V _D to the drops (about 1.5V in this example) voltage lower than 1.7V is determined voltage of the battery voltage monitoring circuit 26, the transistor A transistor cutoff circuit 61 for turning off the transistor 46 is provided at an input to the base of the transistor 46. The transistor cutoff circuit 61, a voltage obtained by dividing the battery voltage V _D by the pair of dividing resistors 62 and 63 in which the connected via a delay circuit 58 to the base of the transistor 46 the transistor 46
The base is obtained by so applying via the delay circuit 58, when the battery voltage V _D is decreased to about 1.5V, the voltage as the transistor 46 is cut-off state to the base of the transistor 46 The resistance values of the split resistors 62 and 63 are set so as to be applied.

Next, the operation of the gas stove of this embodiment will be described.

In the gas stove of the present embodiment, when the ignition / extinguishing button 12 is turned on, the microswitch 18 is turned on in conjunction with this operation, whereby the respective circuits of the control unit 7 receive the battery voltage V from the battery 13. _D is supplied to start each circuit.

At this time, the electromagnetic valve 3 is mechanically opened against a spring (not shown) in conjunction with the ON operation of the ignition / extinguishing button 12, and at the same time, the timer circuits 43 and 44 First, an open drive signal for the solenoid valve 3 is output, whereby the transistors 45 and 46 of the solenoid valve drive circuit 47 are output.
Is turned on and the battery 13 is connected to the solenoid 5 of the solenoid valve 3.
And the solenoid valve 3 is kept open. Then, the supply of gas to the burner 1 is started by driving the solenoid valve 3 to open. In parallel with this, by the scan Parker switch 11a is closed by the operation of the ignition and extinguishing button 12 as described above, wherein the sparker 11 is driven by a battery voltage V _D, thereby, the ignition electrode 10 Ignition sparks

At this time, each of the combustion detection circuits 37 and 38 outputs a misfire detection signal until the burner 1 is ignited and at the initial stage when the burner 1 is ignited, because the electromotive force of the thermocouple 16 is small. Then, the misfire detection signal of the first combustion detection circuit 37 is input to the first timer circuit 43, and the second combustion detection circuit 3
The misfire detection signal 8 is input to the second timer circuit 44 via the disconnection detection circuit 42.

When the misfire detection signal of the first combustion detection circuit 37 is continuously output for the timer time (7 seconds) of the timer circuit 43, that is, the first timer circuit 43 If the electromotive force of the thermocouple 16 does not exceed the predetermined value, the closing drive signal (high-level signal) for the solenoid valve 3 is transmitted to the transistor 45 of the solenoid valve driving circuit 47.
And the transistor 45 is turned off. Thereby, the energization of the solenoid 5 of the solenoid valve 3 is cut off, the solenoid valve 3 is driven to close, and the gas supply to the burner 1 is cut off.

Similarly, the second timer circuit 44 supplies the thermocouple 16 within the timer time (10 seconds) of the timer circuit 44.
When the electromotive force of the solenoid valve 3 does not exceed the predetermined value, the closing drive signal (low level signal) of the solenoid valve 3 is transmitted to the solenoid valve driving circuit 4.
7 to the base of the transistor 46 to turn off the transistor 46 and drive the solenoid valve 3 to close. still,
At this time, since the output of the timer circuit 44 is applied to the base of the transistor 46 through the delay circuit 58, a slight time delay occurs, but the delay time is longer than the timer time (10 seconds) of the timer circuit 44. Since the time is short enough, for example, several milliseconds, the transistor 46 is almost turned off when the timer time elapses.
The close drive signal is applied to the base of the control signal.

In this case, the timer time of the first timer circuit 43 (7 seconds) is equal to the timer time of the second timer circuit 44 (10 seconds).
Second), the solenoid valve 3 is normally driven to close in accordance with the timer time of the first timer circuit 43. For example, the first timer circuit 43 or the like breaks down, and the output of the first timer circuit 43 is When the level is maintained at the level of the open drive signal, the solenoid valve 3 is driven to close according to the timer time of the second timer circuit 44.

In the operation at the time of ignition, the timer time of the first timer circuit 43 or the second timer circuit 44
If the burner 1 is ignited within the predetermined timer time, and becomes equal to or higher than the predetermined value of the electromotive force of the thermocouple 16, this is detected by the first combustion detection circuit 37 or the second combustion detection circuit 38 and these circuits are detected. 37 and 38 output combustion detection signals. In this case, the first timer circuit 43 and the second timer circuit 44 basically continuously output the opening drive signal of the solenoid valve 3.

The operation described above is performed in the same manner when the burner 1 is misfired for some reason after the burner 1 starts burning.

On the other hand, when the food is heated by the combustion of the burner 1, the heating temperature is detected by the first and second temperature detecting circuits 40 and 41 via the thermistor circuit 39. The first temperature detection circuit 40 sends an overheating detection signal to the first timer circuit 43 when the detected heating temperature becomes equal to or higher than 260 ° C. which is a reference temperature for overheating determination of the circuit 40. Output. At this time, when the overheating detection signal is continuously output from the first temperature detection circuit 40 for the timer time (7 seconds), the first timer circuit 43 sends the closing drive signal of the solenoid valve 3 to the transistor 45. Output. As a result, the transistor 45 is shut off, the solenoid valve 3 is driven to close, the combustion of the burner 1 is stopped, and overheating is prevented. At this time, the heating temperature temporarily exceeds the reference temperature due to fluctuations in the combustion flame of the burner 1 or the like, and the overheating detection signal from the first temperature detection circuit 40 is short (<7).
Second) may be output. In such a case, the continuous output time of the overheating detection signal is set to the first timer circuit 4.
Since the timer time is shorter than the timer time of 3, the timer circuit 43 does not output the closing drive signal, and the solenoid valve 3 is maintained in the open state.

Further, the second temperature detecting circuit 41 is adapted to operate when the detected heating temperature becomes 290 ° C. or higher, which is higher than the reference temperature for overheating judgment of the first temperature detecting circuit 40.
The low-level overheating detection signal is output to the base side of the transistor 46 without passing through the timer circuit. The low-level overheating detection signal is applied to the base of the transistor 46 via the delay circuit 58. In this case, since the overheating detection signal is applied to the base of the transistor 46 via the delay circuit 58, the overheating detection signal is applied to the base of the transistor 46 with a slight delay from the output point of the overheating detection signal. The delay is about several milliseconds. Therefore, for example, when the heating temperature suddenly exceeds 290 ° C. from 260 ° C. which is the reference temperature of the first temperature detecting circuit 40 within the timer time (7 seconds) of the first timer circuit 43, Immediately, a low level signal is applied to the base of transistor 46, which causes
6 is shut off, and the solenoid valve 3 is driven to close. still,
At this time, a spontaneous overheating detection signal may be output from the second temperature detection circuit 41 due to noise or the like, but such a spontaneous overheating detection signal is removed by the delay circuit 58 and the transistor 46 No voltage is applied to the base, so that the solenoid valve 3 is not driven to close.

When the thermistor 15 is disconnected during the operation of the gas stove as described above, the disconnection is detected by the disconnection detection circuit 42. At this time, the disconnection detection circuit 42 To the second timer circuit 44. Then, the second timer circuit 44
Outputs the closing drive signal of the solenoid valve 3 to the base of the transistor 46 when the disconnection detection signal is continuously output for the timer time (10 seconds). As a result, the transistor 46 is turned off, and the solenoid valve 3 is driven to close.

Next, a description will be given operation relating to the monitoring of the battery voltage V _D.

[0073] In operation of the gas cooking stove as described above, the battery 13 is exhausted, if the battery voltage V _D has decreased to 2.65V determining a voltage of the comparator 20, which is detected by the comparator 20 ,
The comparator 20 outputs a signal indicating that to the blinking drive circuit 22. At this time, the blinking drive circuit 22 outputs L
The ED lamp 14 is driven to blink, thereby informing the user that the battery 13 will soon need to be replaced.
In this embodiment, the sparker 11 is powered by the battery 13.
By since to perform the ignition of the burner 1, the battery voltage V _D at the time of ignition operation for該着fire is sparker 11
When the power is supplied to the comparator 20, the voltage drops below the determination voltage of the comparator 20 so that the operations of the above-described various circuits may become unstable. After the ignition operation, the sparker 11 becomes inactive and the battery voltage V _D may rise above the determination voltage. And in such a case, Sparker 1
1, the LED lamp 14 flashes only after the ignition operation, and after the ignition operation, the LED lamp 14 turns off again,
In many cases, the blinking of the ED lamp 14 is overlooked. Therefore, in the present embodiment, the judgment voltage of the comparator 20 is set to be relatively high (2.65 V), and the LED lamp 14 is made to blink quickly.

At the stage when the LED lamp 14 blinks, the battery voltage V _D is still a voltage at which the control circuit 17 and the like can operate normally. Therefore, the user continues to use the gas stove to some extent. can do.

Further, the battery voltage V _D is the same as that of the comparator 2
When the voltage drops to 1.9 V, which is the judgment voltage of 1, this is detected by the comparator 21, and the comparator 21 outputs a signal indicating this to the lighting drive circuit 23. At this time, the lighting drive circuit 23 drives the LED lamp 14 to light, thereby informing the user that the battery 13 needs to be replaced. In this case, in the present embodiment, the comparator 21, the battery voltage V _D once 1.
When the voltage drops to 9V, the output is held by the latch circuit 35. For this reason, the power supply to the sparker 11 during the ignition operation causes the battery voltage V
_D is below the determination voltage of the comparator 21 (1.9V), and drops to a voltage such that there is a possibility that the unstable operation of the aforementioned various circuits, again the battery voltage V _D after the ignition operation of the determination even in the case of rises above the voltage, a signal indicating that the battery voltage V _D is decreased to 1.9V is comparator 2
1, the LED lamp 14 is continuously lit. Thus, even for a short time the battery voltage V _D, the effect when dropped in voltage such possibility arises that operation becomes unstable in the aforementioned various circuits, it is necessary to replace the battery 13 to the user It can be surely recognized.

At this time, the output of the comparator 21 indicating that the battery voltage V _D has dropped to 1.9 V is also input to the first timer circuit 43. At this time, the comparator 2
1 is maintained by the latch circuit 35.
The timer circuit 43 outputs a drive signal for closing the solenoid valve 3 to the transistor 45 of the solenoid valve drive circuit 47 when a timer time (7 seconds) elapses from the output point of the comparator 21. As a result, the transistor 45 is turned off, the solenoid valve 3 is driven to close, and the combustion operation of the burner 1 is prohibited.
By inputting the output of the comparator 21 to the solenoid valve driving circuit 47 via the first timer circuit 43 in this way, it is possible to avoid a situation in which the solenoid valve 3 is driven to be closed by electric noise or the like.

By the way, when the battery voltage V _D is temporarily reduced to a level (for example, about 1.8 V) at which the operations of the comparators 20 and 21 become unstable due to the operation of the sparker 11 as described above, The comparator 21 and the first timer circuit 43 do not operate as described above, and the solenoid valve 3
However, there is a possibility that a situation in which the close drive is not performed by the comparator 21 or the first timer circuit 43 may occur.

[0078] However, in this embodiment, until the battery voltage V _D of about 1V is provided with the battery voltage monitoring circuit 26 can operate properly, the battery voltage monitoring circuit 26
The battery voltage V _D is the drops below 1.7V, output via a delay circuit 58 in the closed drive signal (low level signal) to the base of the transistor 46. As a result, the transistor 46 is turned off relatively quickly, and the solenoid valve 3 is driven to close.

Similarly, if the comparator 21 or the first timer circuit 43 fails, the first timer circuit 4
In the case the output of the 3 as maintained at the low level voltage, electrodeposition when vs. voltage V _D drops below 1.7V, the solenoid valve 3 closed driving a blocking state transistor 46 by the battery voltage monitoring circuit 26 can do.

[0080] Further, in this embodiment, even when the battery voltage monitoring circuit 26 as by any chance failure, when the battery voltage V _D is decreased to about 1.5V, the electromagnetic valve 3 by the transistor cut-off circuit 61 It can be driven closed. That is, when the battery voltage V _D decreases to about 1.5 V, the divided resistance 63 of the transistor cutoff circuit 61 is reduced.
, A low-level voltage is applied to the base of the transistor 46, whereby the transistor 46 is turned off and the solenoid valve 3 is driven to close. At this time, the L
Since ED lamp 14 is lit, the user can recognize that the operation of the gas burner is stopped to the battery voltage V _D is lowered.

[0081] Thus, in the gas stove of the present embodiment, ensure that the solenoid valve 3 can be closed drive with a decrease in the battery voltage V _D.

In the embodiment described above, the gas stove having the sparker 11 has been described. However, it is needless to say that the present invention can be applied to a gas stove having a piezoelectric element for ignition and the like. Of course, the present invention can be applied to a combustion device such as a heater.

In this embodiment, the judgment voltage for closing the solenoid valve 3 in the comparator 21 is set to about 1.9 V, and the judgment voltage in the battery voltage monitoring circuit 26 is set to 1.7 V which is lower than that of the comparator 21. Was about
The two determination voltages may be the same.

Further, in this embodiment, the transistor cutoff circuit 61 is constituted by a pair of divided resistors.
As shown in FIG. 3A, a transistor cutoff circuit 6 using a diode 64 having a forward voltage substantially equal to the base-emitter voltage in the conductive state of the transistor 46 is used.
5 or, as shown in FIG. 3B, a transistor cutoff circuit 67 using a Zener diode 66 that generates a constant voltage larger than the base-emitter voltage when the transistor 46 is conducting. You may make it.

In this embodiment, the solenoid valve 3 is mechanically opened and its open state is maintained electrically via the solenoid 5. However, the solenoid valve 3 is opened and the solenoid valve 3 is opened. The state may be maintained electrically.

In this embodiment, the comparator 21
Is connected to the solenoid valve drive circuit 47 via the first timer circuit 43, but may be connected directly to the solenoid valve drive circuit 47 without the first timer circuit 43. .

In this embodiment, the gas stove having one burner has been described. However, a gas stove having two or more burners may be used. In this case, one of a plurality of burners is used. The temperature detector 8 may be provided only in the burner.

When two burners, a high burner and a low burner, are provided, and one of the burners is provided with a temperature detector 8, the temperature detector 8 is used for the high fire burner which is often used in tempura cooking or the like. Preferably, it is provided.

[0089]

As is apparent from the above description, according to the present invention, the voltage of the battery is detected by using the battery as a power source, and when the detected battery voltage falls below a predetermined value, the electromagnetic force of the fuel supply path is reduced. By providing the first and second battery voltage monitoring circuits that respectively output the valve closing drive signals, even if one of the battery voltage monitoring circuits fails, if the other battery voltage monitoring circuit is normal, The solenoid valve can be driven to close in response to the battery voltage drop, and the solenoid valve can be driven to close in response to the battery voltage drop as reliably as possible.

In particular, by setting the operable limit value of the second battery voltage monitoring circuit lower than the limit value of the first battery voltage monitoring circuit, the first battery voltage is reduced when the sparker consuming a large amount of power is activated. Even if the battery voltage monitoring circuit drops to a voltage at which the operation of the battery voltage monitoring circuit becomes unstable, as long as the voltage is at a level at which the second battery voltage monitoring circuit can operate, the battery voltage remains at the second level.
When the battery voltage drops below a predetermined value, the solenoid valve can be driven to close, and the solenoid valve can be reliably driven to close in response to a decrease in battery voltage.

When the battery voltage becomes equal to or lower than a third predetermined value lower than the predetermined value of the second battery voltage monitoring circuit, a voltage for shutting off the switching transistor at the base of the switching transistor of the solenoid valve driving circuit. Is applied by a transistor cutoff circuit to cut off the energization of the solenoid of the solenoid valve and to drive the solenoid valve to close, so that the first and second monitoring circuits fail or become inoperable. , The solenoid valve can be driven to close in response to the battery voltage drop, and the solenoid valve can be driven to close in response to the battery voltage drop more reliably.

Further, since the transistor cutoff circuit is constituted by a pair of divided resistors, the structure can be extremely simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory system configuration diagram of an example of a combustion device of the present invention.

FIG. 2 is a circuit configuration diagram of a main part of the combustion device of FIG. 1;

FIG. 3 is a circuit diagram showing another example of the transistor cutoff circuit.

[Explanation of symbols]

1 ... burner (combustion part), 3 ... solenoid valve, 5 ... solenoid,
11 ... Sparker, 13 ... Battery, 17 ... Control circuit, 27 ...
First battery voltage monitoring circuit, 26: second battery voltage monitoring circuit, 47: solenoid valve driving circuit, 46: switching transistor.

Claims (3)

(57) [Claims] An opening / closing solenoid valve provided in a fuel supply path for supplying fuel to a combustion section; a control circuit for controlling the operation of the combustion section using a battery as a power supply;
A sparker for igniting the firing part, and detecting the voltage of the battery using the battery as a power source, and when the detected battery voltage becomes equal to or less than a first predetermined value, transmitting a signal for closing the solenoid valve. A combustion device comprising: a battery voltage monitoring circuit for outputting; and a solenoid valve driving circuit for closing and driving the solenoid valve in response to the output of the closing drive signal of the battery voltage monitoring circuit, wherein A second battery for detecting a voltage and outputting a signal for closing the solenoid valve to the solenoid valve drive circuit when the detected battery voltage becomes equal to or lower than a second predetermined value which is equal to or lower than the first predetermined value. A voltage monitoring circuit , the second battery voltage
The limit value of the battery voltage at which the monitoring circuit can operate is determined by the first battery.
A combustion device characterized by being lower than a limit value of a pond voltage monitoring circuit . 2. The solenoid valve, wherein the solenoid valve is driven to open by energizing a solenoid and closed by shutting off the energization, wherein the solenoid valve driving circuit comprises a switching transistor connected to the solenoid. A transistor cutoff circuit for applying a voltage for shutting off the switching transistor to a base of the switching transistor when the battery voltage becomes equal to or lower than a third predetermined value lower than the second predetermined value. 2. The transistor according to claim 1, wherein the transistor is connected to a base of the transistor.
Combustion device. 3. The transistor cutoff circuit comprises a pair of divided resistors for dividing the battery voltage to be applied to a base of the switching transistor and applying the divided voltage to the base of the switching transistor. 3. The combustion device according to claim 2 , wherein a voltage for shutting off the switching transistor is applied to a base of the switching transistor when the voltage falls below a predetermined value.