JPH0247655B2 - NENSHOKINOANZENSOCHI - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention incorporates an incomplete combustion detection element and a thermoelectric element heated by a burner into a gas water heater or other combustor to improve safety against incomplete combustion. This invention relates to a safety device for a combustor that takes certain measures.

(Prior Art) As shown in FIG. 2, the applicant of the present application previously installed an electromagnetic safety valve d in the gas supply path c to the main burner a and the pilot burner b, and operated the operating solenoid e of the safety valve d. A drive circuit g for the safety valve d is connected to a power supply f, and the drive circuit g includes a transistor i that turns on and off according to changes in the output of the CO sensor h, and a thermocouple j that is heated by the pilot burner b. A relay k that opens and closes depending on the output change is connected in series with each other, and when the CO concentration reaches an abnormal value during the ignition of the pilot burner b, which the relay k closes, the resistance value of the CO sensor h drops extremely. Then, the transistor i is turned off, the safety valve d is closed, and combustion of the burners a and b is stopped.

In this device, a surge absorbing capacitor l is connected in parallel to the solenoid e, and the thermocouple A certain period of time during the initial ignition of the pilot burner b until a predetermined electromotive force is generated from j, and the safety valve d
In order to keep the valve open, the solenoid e
Capacitor m for forced hold that allows discharge current to flow through
has been established.

(Problem to be Solved by the Invention) If the above capacitors l and m can be configured with one common capacitor, the circuit configuration will be simplified and the size of the entire circuit will be reduced accordingly. It's advantageous.

(Means for solving the problems) The present invention was created in view of the above points, and
A drive circuit for the electromagnetic safety valve is constructed by connecting the operating solenoid of the electromagnetic safety valve installed in the fuel supply path to the main burner and the pilot burner to a power supply, and a CO sensor or other incomplete combustion detection element is connected to the drive circuit. A first control switch that is opened by the incomplete combustion detection output of the pilot burner and a second control switch that is closed by a predetermined electromotive force from the thermoelectric element heated by the pilot burner are interposed in series with each other, and the capacitor and the pilot A changeover switch is provided that switches in conjunction with the ignition operation of the burner and the extinguishing operation of both burners, and when the both burners are extinguished, the changeover switch connects the capacitor to the power source to form a charging circuit for the capacitor. When the pilot burner is ignited, the changeover switch connects the capacitor to the actuating solenoid to form a discharge circuit for forced hold of the electromagnetic safety valve, and further opens in conjunction with the pilot burner ignition operation. The third burner is closed by extinguishing both burners.
A control switch is interveningly connected in parallel to the second control switch and in the charging circuit, and a fourth control switch is connected in conjunction with the ignition operation of the pilot burner and opens in conjunction with the extinguishing operation of both burners. ,
It is characterized in that an intervening connection is made within the drive circuit outside the charging circuit.

(Example) Next, the apparatus of the present invention will be explained based on the illustrated example.

In FIG. 1, 1 is a gas supply path 3 which is a fuel supply path to the main burner 2 and the pilot burner 3.
An electromagnetic safety valve 4 is provided with a dry battery as a power source, and one end of the operating solenoid 1a of the safety valve 1 and the positive pole of the dry battery 4 are connected to a transistor 5 as a first control switch, and a CO as an incomplete combustion detection element. connected via the sensor 6 and the solenoid 1a
The other end and the negative pole of the dry battery 4 were connected via a relay 7, which was a second control switch, to constitute a drive circuit 8 for the safety valve 1 and an incomplete combustion detection circuit.

The excitation coil 7b of the relay 7 is connected to a thermocouple 9 which is a thermoelectric element facing the pilot burner 3, and the thermocouple 9 is heated by ignition of the pilot burner 3, and a predetermined electromotive force is generated after a certain period of time. The coil 7a is energized and the normally open contact 7a of the relay 7 is closed.

Furthermore, a changeover switch 10 and a capacitor 11 are provided, which are switched in conjunction with the ignition operation of the pilot burner 3 and the extinguishing operation of both burners 2 and 3,
The connection point A between the transistor 5 and the solenoid 1a is connected to the positive terminal of the dry battery 4 via the switch 10, and the movable contact 10c of the switch 10 is connected to the other end of the solenoid 1a via the capacitor 11. According to the ignition operation, the switch 1
0 movable contact piece 10c contacts the fixed contact 10a,
A discharge circuit 12 of the capacitor 11 is formed in which the capacitor 11 is connected to the solenoid 1a,
According to the extinguishing operation, the movable contact piece 10c comes into contact with the fixed contact 10b, and the dry cell 4 is connected to the capacitor 11.
A charging circuit 13 for the capacitor 11 to which the capacitor 11 is connected is formed.

Furthermore, the main burner 2 and the pilot burner 3 open in conjunction with the ignition operation of the pilot burner 3.
an opening/closing switch 14 which is a third control switch that closes when the pilot burner 3 is extinguished; and an opening/closing switch 1 which is a fourth control switch that closes when the pilot burner 3 is ignited and opens when the burners 2 and 3 are extinguished.
5 is prepared, and the on-off switch 14 is connected in parallel to the contact point 7a of the relay 7 and in the charging circuit 13, and the on-off switch 15 is inserted in the drive circuit 8 outside the charging circuit 13. Connected.

In the figure, 16 is an on-off valve for the main burner 2, 17,
18 and 19 indicate resistors for current adjustment.

Note that the changeover switch 10, the open/close switch 14, and the open/close switch 15 may be configured as one common switch having three movable contact pieces.

(Function) Next, the operation will be explained. When the ignition operation is performed, the electromagnetic safety valve 1 is manually opened, and the igniter (not shown) is activated, and the pilot burner 3 is activated.
is ignited, and the changeover switch 10 is switched,
The open/close switch 15, which is the fourth control switch, is closed, and the discharge circuit 12 of the capacitor 11 is formed.
The electric charge from the capacitor 11, which is charged by the dry cell battery 4 as a power source through the open/close switch 14 as a third control switch, is discharged for a certain period of time through the operating solenoid 1a of the safety valve 1, and the safety valve 1 is kept open. During this period, the pilot burner 3 is maintained in the ignited state.

After a certain period of time in the initial stage of ignition,
The electromagnetic safety valve 1 is forcibly held in the open state by a predetermined electromotive force generated by the thermocouple 9, which is a thermoelectric element heated by the pilot burner 3, and the pilot burner 3 is maintained in the ignited state until the extinguishing operation is performed. Relay 7 as second control switch
The contact 7a of the safety valve 1 is closed, and the drive circuit 8 of the safety valve 1 is closed.
An incomplete combustion detection circuit is also configured.

At this time, if the main burner 2 is ignited by opening the on-off valve 16, the main burner 2 is ignited by the pilot burner 1. During this ignition, there is generally an abnormal generation of pulses of CO, which is incomplete combustion gas, and an incomplete combustion detection element is detected.
The resistance value of the CO sensor 6 momentarily decreases, causing a surge current to flow through the drive circuit 8 of the electromagnetic safety valve 1, but this current is absorbed by the capacitor 11, causing the drive circuit 8 to malfunction. There is no such thing.

After the main burner 2 is ignited, when the CO concentration is at a normal value, the CO sensor 6 is held at a high resistance value, so the transistor 5, which is the first control switch, is turned on, and the dry battery 4, which is the power source, turns on the CO sensor 6. The operating solenoid 1a is energized and the electromagnetic safety valve 1
is held open, and combustion in the main burner 2 continues.

Also, when the CO concentration reaches an abnormal value during combustion in the main burner 2, the thermocouple 9 is heated by the pilot burner 3, so the contact 7a of the relay 7 is closed as in the above case. Since the CO sensor 6 changes to a low resistance value, the transistor 5 is turned off, the power to the operating solenoid 1a is cut off, the electromagnetic safety valve 1 is closed, and the combustion of the main burner 2 and pilot burner 3 is stopped. It's safe.

Furthermore, when the pilot burner 3 is extinguished or misfired, the on/off switch 15 is open, the thermocouple 9 is not heated, and the contact 7a of the relay 7 is not closed. When the power supply is cut off, the electromagnetic safety valve 1 is in a closed state, and the fail safety of the flame monitoring device composed of the excitation coil 7b of the relay 7 and the thermocouple 9 is ensured.

Therefore, at this time, no gas leakage occurs, and the dry battery 4 does not become exhausted.

In addition, the electromagnetic safety valve 1 is in the open state, and the on-off valve 1 is in the open state.
Even when only the main burner 3 is extinguished by closing only the main burner 6, a pulse-like abnormality of CO will generally occur, and a surge current will flow through the drive circuit 8 of the electromagnetic safety valve 1. is absorbed, and the drive circuit 8 will not malfunction.

(Effects of the Invention) According to the present invention, in the drive circuit and incomplete combustion detection circuit of the electromagnetic safety valve interposed in the fuel supply path to the main burner and the pilot burner,
A capacitor and a changeover switch that is switched in conjunction with the ignition operation of the pilot burner and the extinguishing operation of the main burner and the pilot burner are provided, and when both burners are extinguished, the changeover switch connects the capacitor to the power source of the drive circuit. to form a charging circuit for the capacitor, and when the pilot burner is ignited, the changeover switch connects the capacitor to the operating solenoid of the safety valve to form a discharge circuit for forced hold of the safety valve; A third control switch that opens in conjunction with the ignition operation of the burner and closes when the both burners are extinguished;
A fourth control switch is interveningly connected in parallel to the second control switch and within the charging circuit, and opens in conjunction with the ignition operation of the pilot burner, and is interveningly connected within the drive circuit outside the charging circuit. The capacitor is designed to absorb the surge current generated by abnormal pulses of incompletely combusted gas when the main burner is turned on or extinguished, thereby preventing malfunction of the drive circuit. The circuit is simpler than the conventional device, which has two capacitors for forced hold and for preventing malfunction, respectively, in separate circuits. Moreover, it has the effect of becoming compact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one example of the device of the present invention, and FIG.
The figure is an explanatory diagram of the previously proposed device. 1... Solenoid safety valve, 1a... Operating solenoid,
2...Main burner, 3...Pilot burner,
4... Dry battery (power supply), 5... Transistor (first control switch), 6... CO sensor (incomplete combustion detection element), 7... Relay (second control switch),
8...Drive circuit, 9...Thermocouple (thermoelectric element), 1
0...Selector switch, 11...Capacitor, 12
...Discharge circuit, 13...Charging circuit, 14...Open/close switch (third control switch), 15...Open/close switch (fourth control switch).

Claims (1)

[Claims] 1 Connect the operating solenoid of the electromagnetic safety valve interposed in the fuel supply path to the main burner and pilot burner to a power source to configure a drive circuit for the electromagnetic safety valve, and install a CO sensor or other incomplete combustion detection element in the drive circuit. A first control switch that opens in response to an incomplete combustion detection output from a pilot burner, and a second control switch that closes in response to a predetermined electromotive force from a thermoelectric element heated by the pilot burner are interposed in series with each other, and the capacitor and the A changeover switch is provided that is switched in conjunction with the ignition operation of the pilot burner and the extinguishing operation of both burners, and when the both burners are extinguished, the changeover switch connects the capacitor to the power source and the charging circuit for the capacitor is activated. and when the pilot burner is ignited, the changeover switch connects the capacitor to the operating solenoid to form a discharge circuit for forced hold of the electromagnetic safety valve, and further opens in conjunction with the pilot burner ignition operation. A third control switch that closes when the both burners are extinguished is connected in parallel to the second control switch and in the charging circuit, and is closed in conjunction with the ignition operation of the pilot burner. A safety device for a combustor, characterized in that a fourth control switch that opens in conjunction with the charging circuit is connected to the drive circuit outside the charging circuit.