JPS59129326A - Flame safety device for gas cooking stove - Google Patents

Abstract

PURPOSE:To contrive to elongate the life of a control circuit and to ensure high reliability in a safety device, by locating a control circuit far from high temperature, by leading flame beams to the control circuit by an optical fiber line. CONSTITUTION:An open/close signal from a cock 4 and the flash beam of flame from a burner 3 at the time of ignition, being led by a fiber line 13 are put into a control circuit 12, which puts out a drive signal to a solenoid operated valve 11. A control circuit 12 consists of a beam receptor circuit 14 and a valve driving circuit 15, and the beam receptor circuit 14 consists of a bridge circuit 17 which contains a beam receptor element 16 to convert the beam received from the fiber line 13 into electricity in one side, and a comparator 18 which compares the center potential on the bridge circuit 17. With such an arrangement, there exist not any electronic circuit in the neighborhood of a burner, so that a safety device can be installed in the best position under the atmospheric condition, thereby the reliability of a device can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flame blowout safety device for a gas stove.

Conventional configurations and their problems In the past, many flame blowout safety devices for gas staple stoves, etc., have been devised, such as those using thermocouples and those using light receiving elements, and some have even been put into practical use. There is. The former is a self-power-generating sensing element, and many have a configuration in which the bulb is attracted by the electromotive force of the thermocouple. A diagram of this system is shown in FIG. 6. In FIG. 5, gas is combusted in a burner unit 3 passing from an inlet 1 through a valve unit 2. The valve unit 2 has a built-in gas cock 4 and a safety valve 5, which are operated by a knob 6. When the knob 6 is pressed during ignition, the safety valve 5 is opened by a rod 7 linked to this.
By rotating the cock 4, the cock 4 is also opened and gas flows to the burner unit 3. At the same time, an igniter (not shown) operates to ignite. After a while after ignition, an electromotive force is generated from the thermocouple 8 heated by the flame, and the electromagnetic force generated in the electromagnetic core 9 holds the safety valve 5 open, and the knob 6
Gas flows even if you don't press the button.

When the burner 3 misfires, the electromotive force of the thermocouple 8 disappears and the valve 6 is closed by a spring 10 to prevent gas flow.

However, this method has a slow response due to the heat capacity of the thermocouple.
In addition, it is necessary to hold the valve open until a thermal electromotive force is generated after the burner is turned on, and it is necessary for the person to press the button and wait for a certain period of time.

The latter detects flame emission and has a very fast response. However, the temperature near the gas flame became extremely high, which adversely affected the light receiving element. Furthermore, since gas stoves cook over a flame, the sensor often gets dirty due to boiling over.

Purpose of the Invention The purpose of the present invention is to eliminate such conventional drawbacks, and to apply an optical detection method to achieve a fast response time and to enable the installation of a light receiving element and an electronic circuit in a favorable atmosphere. It is something to do.

Structure of the Invention In order to achieve the above object, the flame safety device for a gas stove of the present invention includes a burner that burns and boils fuel gas, and an optical fiber line that guides light emitted by the flame of the burner to a control circuit. The control circuit has a light receiving circuit coupled to the optical fiber line, and a pulp drive circuit that controls the opening and closing of the fuel gas valve based on the signal from the light receiving circuit. Provides long life and high reliability.

Description of examples The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a system diagram of one embodiment of the present invention.

The gas passes through the solenoid valve 11 from the inlet 1 and reaches the burner 3 from the cock 4, where it is combusted. Reference numeral 12 denotes a control circuit which receives the opening/closing signal of the cock 4 and the light emitted by the fiber wire 13 during combustion of the burner 3, and outputs a signal for driving the solenoid valve 11. For this reason, there is no electronic circuit near the burner, making it possible to install it in a location with the best atmospheric conditions, resulting in improved reliability.

FIG. 2 shows an example of this specific circuit. The control circuit 12 can be roughly divided into a light receiving circuit 14 and a pulp driving circuit 16. Light receiving circuit 1
Reference numeral 4 includes a bridge circuit 17 including on one side a light receiving element (a phototransistor is used here) 16 that converts light from the fiber line 13 into electricity, and a comparator 18 that compares the midpoint potential of the bridge circuit 17. When the gas cock 4 is closed, the pulp drive circuit 15 does not operate because the positive input terminal of the comparator 18 is kept at the ground electromagnetic state by the cock switch 19 interlocked with the gas cock 4.

When the cock 4 is opened, the switch 19 is opened, and the resistor 20,
The result is a divided potential a of 21. Here, when the burner 3 is ignited, the fiber line 13 is passed through and conduction is established so that the phototransistor 16 is irradiated with light. Therefore, the potential becomes the divided potential of the resistors 22° and 23. At this time, since the comparator 18 is designed to have potentials a) and b, the comparator 18 has a high output. Here, since the ratio M unit 18 is a generally known oven collector output comparator, a high output is equivalent to an open state, and base current is supplied to the transistor 24 of the pulp drive circuit 15 through the resistor 25, making the transistor 24 conductive. . Therefore, the solenoid valve 11 opens and gas continues to flow.

If the burner 3 misfires for some reason, the phototransistor 16 will turn off, so the potential 6 will be the voltage of the DC power supply 26.
It becomes electric potential. Therefore, the comparator 18 has a low output (shorted to ground) and the transistor 24 is turned off. Therefore, the solenoid valve 11 is also closed to prevent gas flow.

In this circuit, it is necessary to manually hold the solenoid valve 11 open until the cock 4 is opened and the burner 3 is ignited. In FIG. 2, a timer circuit 27 is provided to solve this problem. The timer circuit 27 constitutes a monostable multivibrator, and the output d becomes high (open collector output) at the same time as the input potential C becomes low, and becomes low after a certain period of time has elapsed.

When the cock 4 is opened, the cock switch 19 causes the potential c i
t, goes low for a certain period of time (makes the transistor 28 conductive.During this time, if an ignition signal is input from the fiber line 13, the solenoid valve 11 is kept open even after the timer output d goes low, but the ignition signal remains If no input is made, the solenoid valve 11 is closed as soon as the timer time expires.By adding this circuit, all you have to do is turn the cock 4 (the usability is the same as with a conventional gas stove).

FIG. 3 shows another example of a system in which the present invention is applied to a gas stove including three gas burners. In the figure, the same operating parts as in FIG. 1 are designated by the same numbers. Gas is distributed from the inlet 1 through the electromagnetic valve 11 into passages leading to each of the burners 3a to 3C, and each passage has a cock 48 to 4C in the middle. Opening/closing signals of cocks 48 to 4C and burners 3a to
The ignition light signal rri7 of 3C is input to the control circuit 29 by the eye bar wires 13a to 13C, and the control circuit 29 is connected to the solenoid valve 1.
Outputs a signal that drives 1.

FIG. 4 shows this specific circuit configuration. Light receiving circuit 3oa,
3ob and 30C each operate almost the same as the light receiving circuit 14 in FIG. 2, but the cock interlocking switches 19a to 19c
This differs from FIG. 2 in that the input point of the signal is input to the negative input side of the comparators 18a to 18c. That is, when the cocks 4d to 4C are closed, the comparators 18a to 18c have a high output, and when the cocks 48 to 4C are open, when there is a flame, the output is ``I'', and when there is no flame, the output is low. The outputs of comparators 18a to 18C are connected to pull-up resistors 31a to 31c.
It is pulled up to the potential of the power supply 26. That is, when the comparator 18 has a high output, it is at the power supply voltage (2), and when it is a low output, it is at the ground potential.

Further, the No contact of each cock switch is connected and pulled up by a resistor 32, and this is input to an inverter circuit 33 with an open collector output. That is, when all the cocks 4 are closed, the output of the inverter 33 becomes a low output, and when any of the cocks 4 is closed, the inverter 33 becomes a high output. Each comparator 18a, 18b
, 18c and the output of the inverter 33 are connected to the AND circuit 3.
4 requires human power. :) When all 4 reconnocks 4 are closed, the output of 188 to 18C is 1, but the inverter 33
The output of the AND circuit 34 becomes low, and the output of the AND circuit 34 becomes low. When any of the cocks 4 opens and the fire burns, the AND circuit 34
Since all the inputs become . At this time, if a misfire occurs, the output of the comparator becomes low, so the output of the AND circuit 34 also becomes low, and the solenoid valve 11
operates to close and prevent gas from escaping. In this operation, even if two or three burners are used together, if any burner misfires, the solenoid valve 11 is closed. Further, even if there are three or more burners, it is easy to add them using the same concept.

The timer circuit 27 has the same function as that shown in FIG. 2, and the operation can be simplified.

In Fig. 4, each combustion signal is detected by an AND circuit, but depending on the configuration of the light receiving circuits 30a to 3Qc and the mounting force of the cock switches 19a to 19c, a pNAND circuit, an OR circuit, a NOR circuit, etc. may also be used. 0J ability.

Furthermore, although this embodiment has been described with a configuration in which the gas is opened and closed by the solenoid valve 11, other types of valves such as self-holding valves using motor pulp or permanent magnets may also be used, and low-power operation is also possible. It becomes realizable.

Effects of the Invention As explained above, the present invention has a configuration in which the flame light is guided to the control circuit by an optical fiber line, so the control circuit can be installed in a place with good atmospheric conditions, and is particularly suitable for use on gas stoves. Long life and high reliability can be achieved by moving the control circuit away from areas where the temperature near the flame is high and there is a lot of dirt due to boiling over. Also, since the flame detection part only has optical fiber, there is no need to worry about electrical leakage and it can be cleaned with peace of mind.

Furthermore, by adding a timer circuit for holding the initial ignition stage, the human operator only needs to turn the cooker, and anyone can easily use it without changing the usability of a conventional gas stove. Furthermore, by combining with logic circuits such as AND and OR, it is possible to control any number of burners with just one gas valve, and has many effects such as being able to be applied to a multi-burner stove with a simple configuration.

[Brief explanation of drawings]

Fig. 1 is a control system diagram showing one embodiment of the flame safety device for a gas stove of the present invention, Fig. 2 is an integrated circuit diagram thereof, Fig. 3 is a system diagram showing another embodiment of the present invention, and Fig. 4 shows the same control circuit diagram, and FIG. 5 shows the configuration diagram of a conventional flame safety device. 3.3a, 3b, 3c...Burner, 11...
...Solenoid valve (fuel gas valve), 12, 29...Control circuit, 13, 13a, 13b, 13cm=
Optical fiber line, 14, 30a, 30b, 3
oc-=... Light receiving circuit, 15... Valve drive circuit, 27... Timer circuit, 34...
AND circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person false 1
Figure J 4 // Figure 3 jc 4c

Claims (3)

[Claims] (1) A burner that burns and boils fuel gas, and an optical fiber line that guides light emitted from the flame of the burner to a control circuit, and the control circuit includes a light receiving circuit coupled to the optical fiber line and a light receiving circuit. A flame safety device for a gas stove configured to include a valve drive circuit that controls opening and closing of a fuel gas valve based on circuit signals. (2) The flame safety device for a gas stove according to claim 1, wherein the valve drive circuit includes a timer circuit that ignores the signal from the light receiving circuit and keeps the gas valve open for a certain period of time after the burner is turned on. (3) A configuration in which a plurality of bars are provided, correspondingly a plurality of optical fiber lines and a plurality of light receiving circuits are provided, and the valve drive circuit is controlled by an AND, OR, or OR circuit of the signals of each light receiving circuit. A flame safety device for a gas stove according to claim 1 or 2.