JP3361372B2 - Control device for gas combustion equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to prevent the release of unburned gas by controlling the opening and closing of an electromagnetic safety valve provided in a gas supply passage by a frame rod and a thermocouple provided near a gas burner. The present invention relates to a control device for gas combustion equipment.

[0002]

2. Description of the Related Art A control device for this type of gas combustion equipment includes
For example, as shown in Japanese Utility Model Application Laid-Open No. 57-66457, a safety valve is normally held open by a thermocouple heated by a gas burner until the thermoelectromotive force of the thermocouple reaches a predetermined value immediately after ignition of the gas burner. In the meantime, there is one that detects the combustion flame with the frame rod and holds the safety valve in the open state by another power source. According to such a technique, electric power is required at the beginning of the operation of the gas burner, but the ignition of the gas burner can be confirmed immediately after ignition and the safety valve can be held in the open state, and after a predetermined time has elapsed, the power for holding the safety valve can be supplied. Can be reduced. However, in this technology, when the ignition operation is performed immediately after the gas burner extinguishes in a state where the thermocouple is not sufficiently cooled and thermoelectromotive force is generated, even if the flame rod does not detect the combustion flame for some reason, the ignition is not performed. ,
There is a problem that the safety valve is kept open and unburned gas is released.

In order to solve such a problem, in the technique disclosed in Japanese Unexamined Patent Publication No. 5-52327, only a first energization control circuit using a frame rod is used until a predetermined time elapses after ignition operation. The safety valve is controlled, and after the lapse of the predetermined time, the safety valve is controlled only by the second energization control circuit using the thermocouple. According to this technology, even if the ignition operation is performed immediately after extinguishing the gas burner, the safety valve is not kept open and the unburned gas is not released unless the flame rod detects combustion flame. .

[0004]

However, the above-mentioned second problem
The technology described above increases power consumption because it continues to operate the frame rod circuit, which consumes considerable power, until the thermocouple produces enough thermoelectromotive force to hold the safety valve open. There's a problem.

The present invention solves each of the problems described above, and the first flame detecting means by the frame rod and the second flame detecting means by the thermocouple are used.
An object of the present invention is to reduce power consumption in a control device for a gas combustion device of this type including a flame detection means.

[0006]

To this end, a control device for a gas combustion apparatus according to claim 1 of the present invention, as shown in FIG. 1, is of an electromagnetic type in a gas supply passage 16 for supplying a fuel gas to a gas burner 32. The safety valve 31 of the gas burner 32
A first flame detecting means 1 for generating a first signal when a combustion flame generated in the gas burner is detected by a frame rod 51 provided nearby, and a thermocouple 6 provided near the gas burner 32.
Second flame detecting means 2 for generating a second signal when 1 is heated
A control device for a gas combustion device that controls opening / closing of the safety valve 31 based on the first and second flame detection means 1 and 2, a first timer means 3 that operates for a relatively short first predetermined time, Following the first timer means, the second timer means 4 is operated for a second predetermined time, and when the operation of the gas combustion equipment is started, first the safety valve 31 is opened for a short time to perform the ignition operation for the gas burner 32, and The first timer means 3 and the first flame detection means 1 are activated to
If the first signal is not detected while the timer means 3 is operating, the safety valve 31 is closed to stop the operation of the gas combustion device, and if the first signal is detected while the first timer means 3 is operating, After the end of the operation of the first timer means 3, the first flame
The operation of the detection means 1 is stopped, the safety valve 31 is kept open during the operation of the second timer means 4, and the second signal is detected after the operation of both the timer means 3 and 4 is completed. The control means 5 is provided for holding the safety valve 31 open only when the safety valve 31 is open.

The control means 5 of the invention according to claim 1 repeatedly operates the first timer means 3 and the second timer means 4 a plurality of times at the time of starting the operation of the gas combustion equipment. If the first signal is not detected during each operation, the safety valve 31 is closed to stop the operation of the gas combustion equipment after the lapse of the short time, and the first signal is detected during the operation of the first timer means 3. If so, the safety valve 31 is always kept open during the operation of the second timer means 4 following the stop of the operation of the first flame detection means 1, and the second valve is operated after the operation of both timer means 3, 4 is completed. The safety valve 31 is preferably configured to be held in the open state only when a signal is detected.

Further, the control means 5 of the first and second aspects of the present invention includes the first flame detection means 1 prior to the ignition operation for the gas burner 32 at the time of starting the operation of the gas combustion equipment.
It is preferable to detect at least one of the first signal from the second flame detection means 2 and the second signal from the second flame detection means 2 and to stop the operation of the gas combustion equipment when a corresponding signal is detected. .

[0009]

In the first aspect of the present invention, the control means 5 first opens the safety valve 31 for a short time to ignite the gas burner 32 when starting the operation of the gas combustion equipment, and at the same time, the first timer means 3 and the first flame detection. If the means 1 is activated and the gas burner 32 is not ignited during the operation of the first timer means 3 and therefore the first signal from the first flame detection means 1 using the flame rod 51 is not detected, the thermocouple Regardless of whether or not the second signal from the second flame detecting means 2 using 61 is detected, the safety valve 31 is closed and the operation of the gas combustion equipment is stopped after the elapse of the short time. When the first signal from the first flame detecting means 1 is detected during the operation of the first timer means 3, the control means 5 controls the first timer means 3 after the operation is finished.
(1) The operation of the flame detecting means 1 is stopped, and the safety valve 31 is always kept open during the operation of the second timer means 4. After the operation of both timer means 3 and 4, the control means 5 holds the safety valve 31 in the open state only when the second signal from the second flame detection means 2 is detected.

In the invention of claim 2, in the invention of claim 1, the control means 5 sequentially and repeatedly operates the first timer means 3 and the second timer means 4 a plurality of times to operate the first timer means 3 and the second timer means 3. During the operation of the timer means 4 and after the operation of both the timer means 3 and 4 is completed, the safety valve 3 is operated in the same manner as in the first item.
Control 1

According to a third aspect of the present invention, the first and second aspects are provided.
In the invention described above, the control means 5 detects at least one of the first signal from the first flame detection means 1 and the second signal from the second flame detection means 2 prior to the ignition operation for the gas burner 32, and responds. When the signal is detected, there is an abnormality in the corresponding flame detection means, so the operation of the gas combustion equipment is stopped.

[0012]

As described above, according to the present invention, if the gas burner 32 is not ignited during the operation of the first timer means 3, the presence or absence of the second signal from the second flame detecting means 2 by the thermocouple is detected. Nevertheless, since the safety valve 31 is closed and the operation of the gas combustion device is stopped, the unburned gas is not released even when the thermocouple is generating thermoelectromotive force immediately after the gas burner is extinguished. Further, when the gas burner 32 is ignited and the first signal is detected during the operation of the first timer means 3, the first signal is detected .
After the end of the operation of the timer means 3, the operation of the first flame detection means 1
While being stopped, the safety valve 31 is opened by the control means 5 until <br/> to become second flame by that hold the detecting means 2 is made has elapsed a second predetermined time period Retained . this
When the first flame detection means 1 that consumes a considerable amount of power due to
Since the period is shortened , the power consumption can be reduced.

According to the second aspect of the present invention, the safety valve 31 is operated if the first timer means 3 and the second timer means 4 are repeatedly operated a plurality of times and the first signal is not detected during the operation of the first timer means 3. Since the operation of the gas combustion equipment is stopped by closing the above, even if the gas burner 32 is once ignited and then extinguished, the release of unburned gas can be stopped in a short time.

According to the invention of claim 3, the control means 5
Since the operation of the gas combustion equipment is stopped when at least one of the flame detection means is abnormal prior to ignition of the gas burner 32, the safety can be further improved.

[0015]

2 to 6 are examples in which the present invention is applied to a main stop type gas instantaneous water heater, and the present invention will be described below. As shown in FIG. 2, the instant water heater 10 includes a heat exchanger 11 having a water supply pipe 12 and a hot water discharge pipe 13 in the main body of the appliance, and a gas burner 3 for heating the water supply pipe 12.
Equipped with 2. The water control valve unit 2 is provided on the inlet side of the water supply pipe 12.
0 is connected, a gas control valve unit 30 is connected to the inlet side of the gas supply passage 16 for supplying gas to the gas burner 32, and the housings of both control valve units 20 and 30 are integrally formed.

The water control valve portion 20 is provided with a diaphragm chamber 21 in a water supply passage therein, and a water faucet diaphragm 24 so as to open and close a valve port 23 leading to the diaphragm chamber 21. The faucet diaphragm 24 is provided with a valve opening 24a at a central portion corresponding to the valve opening 23, and a valve spindle 25a penetrating the housing of the water control valve portion 20 in a liquid-tight manner so as to be slidable.
Faucet pilot valve 25 attached to the tip of
It is normally provided in a state of being pressed and biased via the spring 25b so as to close the valve opening 24a. The faucet diaphragm 24 is provided with a water passage port 24b in addition to the valve port 24a.
When is closed, the water in the water supply passage enters the back side of the faucet diaphragm 24 through the water passage port 24b, and the faucet pilot valve 25 is closed, that is, the valve port 23 of the diaphragm chamber 21 is closed. Hold and water control valve section 2
0 is configured to be held in a water-stopped state.

The diaphragm chamber 21 is partitioned by a hydraulic diaphragm 22 into a primary pressure chamber 21a and a secondary pressure chamber 21b. On the side of the primary pressure chamber 21a, a hydraulic diaphragm 22 surface flows into the diaphragm chamber 21 through a valve port 23. A water amount adjusting valve 26 for adjusting the amount of incoming water is attached via a spring 26a, and the water amount adjusting valve 26 adjusts the flow rate of water flowing through the water supply passage. Primary pressure chamber 2
The water flowing into the water la 1a is supplied to the water supply pipe 12 by a water amount distribution valve 28 rotatably provided in the housing of the water control valve unit 20.
And the hot water supply pipe 13, and the water supply pipe 12 is rotated by rotating the water distribution valve 28 via the valve shaft 28a.
The amount of water supplied to the hot water and the amount of water mixed with the hot water flowing through the hot water outlet pipe 13 can be adjusted. A hot water temperature adjusting lever 29 is provided on the valve shaft 28a.
A hot and cold water changeover switch 48 for detecting the rotation of the valve shaft 28a rotated by the operation of 9 is provided closely.

The secondary pressure chamber 21b side of the diaphragm chamber 21 is communicated with a venturi pipe portion 14 provided in the water supply pipe 12 through a bypass pipe line 15, and when the water is flowing through the water supply pipe 12, the secondary pressure chamber 21b. 21b becomes a lower pressure than the primary pressure chamber 21a, and the water amount control valve 26 moves leftward in FIG. 2, so that the hydraulic automatic gas valve 33 provided in the gas flow path of the gas control valve portion 30 is opened as described later. At the same time, the water flow detection switch 47 is turned on. Reference numeral 27 is a drain plug for draining water from both chambers of the diaphragm chamber 21, and 17 is a strainer.

The gas control valve portion 30 provided in the gas supply passage 16 of the gas burner 32 has a hydraulic automatic gas valve 33 which opens and closes a valve opening 33a in the internal gas flow passage in association with the movement of the water quantity control valve 26. , A gas governor 41 whose opening is adjusted according to the gas pressure supplied to the gas flow path, and a gas control valve section 3
An electromagnetic safety valve 31 provided at a valve opening near the 0 gas inlet to prevent outflow of unburned gas at the time of misfire, and an instrument plug 35 provided at a valve opening 35a for opening and closing the gas flow passage are provided. Has been.

The automatic hydraulic gas valve 33 has a valve shaft 34 which is slidably and liquid-tightly penetrated through the housings of the gas control valve portion 30 and the water control valve portion 20 and is connected to the hydraulic diaphragm 22 in the diaphragm chamber 21. When the water is not flowing through the water control valve section 20, the spring 33b causes the valve opening 33a to move.
It is pressed by and closed. In the vicinity of the valve shaft 34, a water flow detection switch 47 operated by a switch operation piece 34a provided in a part of the valve shaft 34 is provided.
The water flows to 0, the valve shaft 34 moves, and the switch operating piece 34a
Thus, when the water flow detection switch 47 is turned on, the ignition stroke of the gas burner 32 described later is entered.

The valve body 31c of the electromagnetic safety valve 31 normally has a valve opening 31a closed by a spring. Valve body 31
c is pushed by the valve shaft 40 so that the valve opening 31a
Open the valve and energize the electromagnet 31b in that state.
c is held in the open state, and when the energization is stopped, it is pressed against the valve opening 31a by the spring to close it.

As a drive source for opening and closing the faucet pilot valve 25 of the instrument plug 35, the safety valve 31, and the gas control valve portion 30, a motor 36 using a dry battery as a drive source is provided. The cam shaft meshed with the motor shaft via a reduction gear (not shown) includes first to third cams 37a, 3a.
7b and 37c are provided. The first cam 37a opens and closes the water control valve unit 20 via the motor interlocking lever 39a and the faucet opening / closing lever 39b by the rotation of the motor 36. The faucet opening / closing lever 39b is connected to the base of the valve spindle 25a of the faucet pilot valve 25, and the valve spindle 25a is operated by the operation of the faucet opening / closing lever 39b.
Moves back and forth, and the faucet pilot valve 25 opens the valve opening 24.
The water control valve unit 20 is opened and closed by opening a.

The second cam 37b starts pushing the valve shaft 35b of the instrument plug 35 when the motor 36 rotates by a predetermined angle, and the valve shaft 35b follows the rotation of the motor 36.
Is moved back and forth to open and close the instrument plug 35. The third cam 37c moves the valve shaft 40 of the safety valve 31 forward and backward by the rotation of the motor 36 to open the valve body 31c to the adsorption position of the electromagnet 31b.

Further, these cams 37a, 37b, 37
Two cam switches 46a and 46b that face the c and detect whether or not the motor 36 has rotated to a predetermined angle.
(Micro switch) is provided. The operation panel (not shown) provided on the front surface of the instrument body is provided with a feather touch type push button 38, and the push button 3 is provided on the back side thereof.
A start-up switch 49 that is turned on / off by pressing 8 is provided.

A flame rod 51 for confirming the operation of the gas burner 32, a thermocouple 61, and an ignition electrode 45a for igniting the gas burner 32 are provided immediately above the gas burner 32. Motor 36, safety valve 31,
Igniter (ignition circuit 45 and ignition electrode 45a), electronic control unit 43, frame rod circuit 5 described below
0, a common dry battery (for example, 3 volts) is used as a power source for operating the thermocouple circuit 60 and the like.

As shown in FIG. 2, the instant water heater of this embodiment is controlled by an electronic control unit 43 composed of a microcomputer. The electronic control unit 43 controls the operation of the entire instant water heater, a central processing unit (CPU), a read only memory (ROM), a readable and writable memory (RAM), and exchanges data between the CPU and the outside. The gas burner 3 consists of the interface to perform and the frame rod 51
2, a flame rod circuit 50 for confirming that combustion flame is generated, a thermocouple circuit 60 for confirming that the gas burner 32 is operated by the thermocouple 61, a valve drive circuit 44 for operating the safety valve 31, and an ignition electrode. An ignition circuit 45 for igniting the gas burner 32 by 45a is connected.
Although not shown in the drawings for the sake of simplicity, the motor 36, cam switches 46a and 46b, water flow detection switch 47, hot water switch 48 and start switch 49 are also connected to the electronic control unit 43. A control program for the RO M for controlling the operation of the water heater moment is stored, the RA M tapping temperature, and various detection values is adapted to be stored.

In comparison between the present embodiment and each claim, the frame rod circuit 50 including the frame rod 51 and a part of the electronic control unit 43 constitute the first flame detecting means 1 and the thermocouple 61.
Part of the thermocouple circuit 60 and the electronic control unit 43 including the second
The first timer means 3 and the second timer means 4, which respectively configure the flame detection means 2 and correspond to the first timer and the second timer described later, are configured by a part of the electronic control unit 43. The control means 5 is composed of a part of the structure of the instantaneous water heater 10 and a part of the electronic control unit 43.

Next, the frame rod circuit 50 including the frame rod 51 will be described with reference to FIG. Electronic control unit 4
A high level signal is output from the output port 43a of 3
Further, in a state in which the power supply voltage VE (DC of 3 V by a dry battery) is applied to the power supply terminal VF connected to the drain of the field effect transistor FET (which case will be described later), the transistor Q1 is Resistance R
1, the base current is supplied to conduct the current, and the transistor Q2 is supplied with the base current via the resistor R3 to conduct. Therefore, the frame rod circuit 50 is connected to the power supply VE to be energized. As a result, the booster circuit including the transformer T, the resistor R5, and the transistor Q3 operates, and an AC voltage (for example, 200 to
300 volt) is generated. This booster circuit consumes considerable power.

Since the combustion flame of gas has a rectifying action, if the combustion flame 32a is generated in the gas burner 32, the secondary coil Ta, the resistor R6, the frame rod 51, the combustion flame 32a and the resistance are generated by the AC voltage. A half-wave rectified flame current flows through R7 in the direction indicated by the arrow, and a negative voltage with respect to ground is generated at point A. This voltage is smoothed by the capacitor C2, the resistor R8 and the capacitor C3.
The noise component is removed by the filter circuit consisting of
It is applied between the gate and the source of the field effect transistor FET. The field effect transistor FET is normally conducting, but is turned off when a negative voltage is applied between the gate and the source. Therefore, when the power supply voltage VE is applied to the drain of the field effect transistor FET, a high level signal is generated at the input port 43b of the electronic control unit 43 when the combustion flame 32a is generated in the gas burner 32, and the combustion flame 32a is generated. When it has not occurred, a low level signal is input. This high level signal output from the flame rod circuit 50 when the combustion flame 32a is generated in the gas burner 32 is the first signal indicating that the combustion flame 32a is generated by the operation of the gas burner 32.

Next, the thermocouple circuit 60 including the thermocouple 61 will be described with reference to FIG. Output port 4 of electronic control unit 43
In the state where the low level signals are output from 3c and 43d (how this state occurs will be described later), the transistor Q13 is supplied with the base current via the resistor R16 and becomes conductive, whereby the regulator IC1 is turned on.
Power supply voltage VE is applied to the input side of the regulator IC
A predetermined voltage VI is output to the output side of 1. As a result, the transistor Q15 is rendered conductive by being given a base current via the resistor R20, and the transistor Q14 is rendered conductive by the resistor R18.
A base current is given to the gate via the gate to conduct. As a result, the comparator IC2 is connected to the power supply VE.

The output terminal of the comparator IC2 is connected to the ground only when the voltages of the two input terminals (+ terminal and − terminal) are compared and the + terminal voltage <− terminal voltage. The output voltage VI of the regulator IC1 is applied to the negative terminals of the comparator IC2 by the resistors R25, 26,
The reference voltage divided by 27 is input, and the voltage between the output side of the regulator IC1 and the input terminal 61a of the thermocouple 61 is divided into the + terminal by the resistor R23, the adjustable semi-fixed resistor VR and the resistor R24. The voltage is input. On the other hand, in this state in which the low level signal is output from the output port 43d, the transistor Q11 is cut off, and the power supply voltage VE does not affect the voltage at the + terminal. Since the thermocouple 61 is + grounded, a negative voltage is generated at the input terminal 61a by heating the thermocouple 61.

When the thermocouple 61 is not heated and the thermoelectromotive force is 0, the positive terminal voltage is greater than the negative terminal voltage. Therefore, the output terminal of the comparator IC2 is non-conductive with respect to the ground, and therefore the input terminal of the electronic control unit 43. A high level signal (= power supply voltage VE) is input to 43e. As the thermocouple 61 is heated and the thermoelectromotive force gradually increases, the + terminal voltage gradually decreases. When the thermoelectromotive force of the thermocouple 61 exceeds a predetermined value, the + terminal voltage <−terminal voltage and the comparator IC2 Since the output terminal is electrically connected to the ground, a low level signal is input to the input terminal 43e of the electronic control unit 43. This low level signal output from the thermocouple circuit 60 is the second signal indicating that the thermocouple 61 is being heated by the operation of the gas burner 32.

In the above state, if only the output signal from the output port 43c of the electronic control unit 43 changes to the high level, the transistor Q12 is rendered conductive by the base current given through the resistor R14, and the transistor Q11 becomes the resistor R12. A base current is given to the gate via the gate to conduct. As a result, the + terminal of the comparator IC2 is connected to the power source VE via the resistor R28 and the diode D1, so that the + terminal voltage is always> irrespective of the thermoelectromotive force of the thermocouple 61.
-It becomes the terminal voltage. Therefore, in this state, the thermocouple circuit 6
As long as 0 is operating normally, the thermocouple circuit 60 always inputs a high level signal indicating that the thermocouple 61 is not heated to the input terminal 43e of the electronic control unit 43 (does not generate the second signal). ). The pre-check of the thermocouple circuit 60 described later is performed in this state.

Next, the operation of the above embodiment will be described with reference to FIGS. 2, 5 and 6. First, when the user pushes the push button 38 to turn on the activation switch 49, the motor 36 is activated. The first cam 3 driven by the motor 36
By the rotation of 7a, the motor interlocking lever 39a and the faucet opening / closing lever 39b cooperate with each other to retract the valve spindle 25a and open the water control valve section 20. As a result, water passes through the diaphragm chamber 21 and the water distribution valve 28,
And distributed to the hot water supply pipe 13 and supplied. If the amount of water supplied to the water supply pipe 12 through the venturi tube portion 14 becomes the predetermined value or more, reduces the pressure in the secondary pressure chamber 21b, pressure diaphragm 22 moves to the left in FIG. 2, the valve shaft 34 Press to start opening the hydraulic automatic gas valve 33.

When the cam shaft rotates 80 degrees by the operation of the motor 36, the first cam switch 46a is turned on, the electronic control unit 43 detects this and temporarily stops the motor 36, and the hydraulic automatic gas pushed by the hydraulic diaphragm 22 is automatically stopped. The valve shaft 34 of the valve 33 moves leftward as it is, and stands by until the water flow detection switch 47 is turned on. When the amount of water supplied to the heat exchanger 11 reaches a sufficient amount and the water flow detection switch 47 is turned on, the electronic control unit 43 restarts the motor 36, starts the timer from this water flow detection, and starts the time ta (Fig. After waiting 6 seconds (for example, 0.2 seconds), the igniter is activated.

During this time ta, that is, prior to the ignition operation of the gas burner 32 by the igniter, the electronic control unit 43 outputs a high level signal from the output port 43a and a low level signal from the output ports 43c and 43d. The precheck shown in FIG. 6 is performed in step 100 of FIG. With the water flow detection switch 47 turned on, the power supply terminal V of the field effect transistor FET of FIG.
F is always connected to the power source VE via the water flow detection switch 47.

At this point before the ignition operation, the combustion flame 32
Since a does not exist, the frame rod circuit 50 generates a low level signal and makes it the input port 43b of the electronic control unit 43. A high level signal (first signal) indicating that combustion flame is generated and input to the electronic control unit 43 is caused by a failure of the flame rod circuit 50, a failure such as an afterglow in the gas combustion equipment, or the like. This is the case when the abnormal condition occurs. Therefore, when the electronic control unit 43 detects this first signal, it immediately stops the operation of the gas combustion equipment. If the first signal is not detected, the electronic control unit 43 sets the signal from the output port 43c to the high level. As described above, in this state, the high level signal should always be input to the input port 43e of the electronic control unit 43, and the low level signal is input (the second signal is generated). The case is when there is an abnormality such as a failure of the thermocouple circuit 60. Therefore, the electronic control unit 43
When the signal is detected, the operation of the gas combustion equipment is stopped immediately.

If the second signal is not detected, the electronic control unit 43 executes the control operation at step 101 after the lapse of time ta.
Proceed to. By the above-mentioned step 100, a pre-check is made as to whether the flame rod circuit 50, the thermocouple circuit 60 and the gas combustion equipment are operating normally. The signal from the output port 43c is at a high level only when the thermocouple circuit 60 is prechecked, and is at a low level otherwise.

In step 101, the electronic control unit 43
Starts the motor 36, and its operation causes the third cam 3 to move.
7c pushes the valve shaft 40 to open the safety valve 31, and when the rotational position of the motor 36 reaches a predetermined angle, the second cam switch 46b is turned on. The electronic control unit 4 detects this ON state.
3 holds the safety valve 31 in an open state by supplying a predetermined current to the electromagnet 31b. The motor 36 continues to rotate, and the second
The cam 37b pushes the valve shaft 35b to open the instrument stopper 35, which is fully opened at a predetermined angle (305 in this embodiment).
Degree), the first cam switch 46a is turned off, and the electronic control unit 43 stops the motor 36 by detecting the turning off. In this state, the safety valve 31, the automatic hydraulic gas valve 33, and the instrument plug 35 are opened, so that the fuel gas is supplied to the gas supply passage 16
It is ejected from the gas burner 32 via the gas nozzle 42 at the tip.

Simultaneously with the activation of the motor 36 in step 101, the electronic control unit 43 sets the signal from the output port 43a to a high level to energize the frame rod circuit 50 to start it, and set the ignition timer, the igniter (the ignition electrode 4).
5a and the ignition circuit 45) and the first timer to start the ignition operation for the gas burner 32, and the control operation proceeds to step 102. An ignition timer for limiting the ignition time to a predetermined small time tb (for example, 2 seconds) and the first
The first timer for measuring the predetermined time t1 (for example, 2 seconds) is built in the electronic control unit 43.

As shown in FIG. 6, first, the flame rod circuit 50 is energized, and at the same time, the igniter is activated to ignite the fuel gas ejected from the gas burner 32, and the combustion flame 32a generated thereby is slightly lagged. After being detected by the frame rod 51, the frame rod circuit 50 generates a first signal, which is input to the input port 43b of the electronic control unit 43. Electronic control unit 4
3 repeats steps 102 and 110 until it detects this first signal, and if it detects the first signal, it proceeds from step 102 to step 103 to stop the operation of the igniter. If the gas burner 32 is not ignited for some reason, and the ignition timer has passed the predetermined short time tb without the first signal being detected in step 102, the electronic control unit 43 performs the control operation from step 110 to step 111. Then, the safety valve 31 is closed to stop the energization of the igniter and the flame rod circuit 50 to stop the operation of the gas combustion device.

In step 104 following step 103,
The electronic control unit 43 waits until the measurement time of the first timer reaches the first predetermined time t1, and although not shown in FIG. 5, if the first signal is not detected during this time, the safety valve 31
To stop the operation of the gas combustor. The first predetermined time t1 in the state where the first signal is detected
When it reaches, the control operation is shifted to step 105, the energization to the frame rod circuit 50 is stopped to stop its operation, and the built-in second timer is started. As a result, the frame rod circuit 50 that consumes power is stopped, so that the power consumption thereafter is significantly reduced. On the other hand, the electronic control unit 43 continues to energize the safety valve 31 via the valve drive circuit 44, thereby keeping the safety valve 31 in the open state.

In step 106 following step 105, the process waits until the second timer reaches the second predetermined time t2 (eg, 28 seconds), during which the heat of the thermocouple 61 heated by the combustion flame 32a of the gas burner 32 is heated. The electromotive force increases and the thermocouple circuit 60 produces a second signal,
The signal is input to the input port 43e of the electronic control unit 43. When the measurement time of the second timer reaches the second predetermined time t2, the electronic control unit 43 advances the control operation to 107, and opens the safety valve 31 when detecting the second signal input to the input port 43e. Hold to continue operation of gas combustion equipment.

By closing a hot water tap (not shown), the amount of water passing through the water supply pipe 16 is reduced to a predetermined value or less, and the water control valve section 20 is reached.
When the valve shaft 34 is returned by the operation of the above and the water flow detection switch 47 is turned off, the electronic control unit 43 detects this and sets the signal from the output port 43d to the high level, and the power supply terminal VF of the field effect transistor FET. The voltage becomes zero. As a result, the thermocouple circuit 60 does not generate the second signal, so that the electronic control unit 43 executes the control operation in step 10.
From 7 to step 108, the safety valve 31 is closed and the operation of the gas combustion equipment is stopped. Even when the safety valve 31 is no longer detected due to the extinguishing of the combustion flame 32a or the failure of the thermocouple circuit 60 due to some cause, the operation of the gas combustion device is similarly stopped. When the user presses the push button 38 to finish the hot water supply, the electronic control unit 43 detects that the activation switch 49 is turned on and stops energizing the safety valve 31 to stop the operation of the gas combustion device. To do.

According to the above embodiment, the first predetermined time t1
If the gas burner 32 is not ignited therein, the safety valve 31 is closed and the operation of the gas combustion equipment is stopped regardless of the presence or absence of the second signal from the thermocouple circuit 60 by the thermocouple 61. Therefore, immediately after the gas burner 32 is extinguished. Therefore, even when the thermocouple 61 generates a thermoelectromotive force, the unburned gas is not released. Further, if the gas burner 32 is ignited within the first predetermined time t1 and the first signal is detected, the second predetermined time t2 subsequent thereto elapses and the safety valve 3 by the thermocouple circuit 60 elapses.
Since the frame rod circuit 50 that consumes a considerable amount of power is stopped and the safety valve 31 is held in the open state by the electronic control device 43 until the holding of 1, the power consumption of the power source such as a dry battery is reduced. You can make it last longer.

Prior to ignition of the gas burner 32, the electronic control unit 43 pre-checks whether the flame rod circuit 50, the thermocouple circuit 60 and the gas combustion equipment are operating normally, and either of them is checked. When an abnormality occurs, the operation of the gas combustion device is stopped, so that the safety can be further improved. Note that this precheck may be performed only on one of the frame rod circuit 50 and the thermocouple circuit 60.

In the above embodiment, the flame 32a of the gas burner 32 is checked by the flame rod circuit 50 using the flame rod 51 until the thermocouple 61 is heated and the thermocouple circuit 60 generates the second signal. Is performed only once when the gas burner 32 is ignited.
In the modification shown in FIG. 3, the combustion flame 32 is ignited after the ignition of the gas burner 32 and before the thermocouple circuit 60 generates the second signal.
The existence of a is checked again. This modification will be described below.

In the flowchart of the modified example shown in FIG. 7, in steps 100 to 106, step 110 and step 111, the time until the time-out of the second timer (second predetermined time t2) is 13 seconds. Except for Figure 5
Since it is the same as each step of the same number in the flow chart shown in FIG.

When the time measured by the second timer reaches the second predetermined time t2 in step 106, the electronic control unit 43 advances the control operation to step 120 and energizes the frame rod circuit 50 again (second time shown in FIG. 8). Energization) to start this, and also to start the first timer. After some time required for the frame rod circuit 50 to rise, the electronic control unit 43 advances the control operation to step 121 to check whether or not the first signal from the frame rod circuit 50 is detected. This first signal is detected (Fig. 8
5), the same steps 122 to 125 as steps 104 to 107 of the flowchart shown in FIG. 5 are executed. Second in step 125
If no signal is detected, the electronic control unit 43 advances the control operation from step 125 to step 126, closes the safety valve 31, and stops the operation of the gas combustion device. If the first signal is not detected in step 121, the electronic control unit 4
3 stops the energization to the frame rod circuit 50 and stops it (not shown in FIG. 7), and the control operation is step 1
26, the safety valve 31 is closed and the operation of the gas combustion equipment is stopped.

Even if the gas burner once ignites the gas burner, the combustion flame may disappear immediately after that, but in such a case, according to this modified embodiment, the second signal is not detected immediately, so immediately. The safety valve 31 is closed, so the amount of unburned gas released is reduced. In the above modification, the first signal is detected twice, but it may be detected three times or more. In this case, the first predetermined time t1 is 2 in each case.
The first predetermined time t1 and the second predetermined time t2
The total sum of the above may be about 30 seconds.

In each of the above embodiments, the frame rod circuit 5
The first predetermined time t1 of energizing 0 is constant regardless of the presence or absence of the first signal indicating the presence of the combustion flame 32a. However, if the first signal is detected, the combustion flame becomes stable during ignition. The power supply to the frame rod circuit 50 may be stopped after a necessary time lag. In this case, the total sum of the first predetermined time t1 and the second predetermined time t2 becomes slightly shorter, but if necessary, the second predetermined time t2 may be made slightly longer. Although the first predetermined time t1 is set to 2 seconds in each of the above embodiments, it may be appropriately selected within the range of 0.1 to 3 seconds.

In each of the above embodiments, the electromagnetic safety valve has a type in which the valve is not opened from the closed state only by the magnetic force generated in the exciting coil, but the present invention is closed by the magnetic force generated by the exciting coil. It goes without saying that it is also possible to use a self-suction type electromagnetic safety valve for valve operation.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a control device for a gas combustion device according to the present invention.

FIG. 2 is a diagram showing the overall configuration of an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a frame rod circuit of the embodiment shown in FIG.

FIG. 4 is a diagram showing an example of a thermocouple circuit of the embodiment shown in FIG.

5 is a flowchart of an example of a control program used in the embodiment shown in FIG.

FIG. 6 is a time chart explaining the operation according to the flowchart shown in FIG.

FIG. 7 is a flowchart of a modification of the control program used in the embodiment shown in FIG.

FIG. 8 is a time chart for explaining the operation according to the flowchart shown in FIG.

[Explanation of symbols]

1 ... 1st flame detection means, 2 ... 2nd flame detection means, 3 ... 1st timer means, 4 ... 2nd timer means, 5 ... Control means, 20 ...
Gas burner, 20a ... Combustion flame, 21 ... Gas supply path, 23
... Safety valve, 51 ... Frame rod, 61 ... Thermocouple.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) F23N 5/10 310 F23N 5/12 F23N 5/20 103

Claims (3)

(57) [Claims] 1. A first signal is generated when an electromagnetic safety valve is provided in a gas supply passage for supplying fuel gas to a gas burner, and a flame rod provided in the vicinity of the gas burner detects a combustion flame generated in the gas burner. A flame detecting means and a second flame detecting means for generating a second signal when the thermocouple provided near the gas burner is heated are provided, and the first and second flame detecting means are provided.
In a control device for a gas combustion device that controls opening and closing of the safety valve based on flame detection means, a first timer means that operates for a relatively short first predetermined time, and a second predetermined time operation that follows the first timer means. When the gas combustion equipment is started to operate, first, the safety valve is opened for a short time to perform the ignition operation for the gas burner, and the first timer means and the first flame detection means are operated to operate the first timer means. If the first signal is not detected during the operation of the timer means, the safety valve is closed to stop the operation of the gas combustion device, and if the first signal is detected during the operation of the first timer means, the first timer. After the end of the operation of the means, the first flame detection
Holds always the safety valve during the operation of the prior SL second timer means stops the actuation means to the open state, also the safety valve only when after operation completion of both the timer means that the second signal is detected A control device for a gas combustion device, characterized by comprising control means for holding it in an open state. 2. The control means repeatedly operates the first timer means and the second timer means a plurality of times at the start of operation of the gas combustion equipment, and the first timer means operates during each operation of the first timer means. If no signal is detected, the safety valve is closed to stop the operation of the gas combustion device after the lapse of the small time,
If the first signal is detected during the operation of the first timer means, the safety valve is always kept open during the operation of the second timer means following the stop of the operation of the first flame detecting means, and both timers The safety valve is kept open only when the second signal is detected after the operation of the means is completed.
A control device for a gas combustion device according to 1. 3. The control means outputs a first signal from the first flame detection means and a second signal from the second flame detection means prior to the ignition operation for the gas burner at the start of operation of the gas combustion device. The control device for a gas combustion device according to claim 1 or 2, wherein at least one of the detections is performed, and when the corresponding signal is detected, the operation of the gas combustion device is stopped.