JP3322951B2 - Safety device and combustion device for combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a combustion such as a gas combustion apparatus
It relates to a safety device and a combustion device for the device .

[0002]

2. Description of the Related Art Conventionally, a safety device for a gas combustion device has an electromagnetic valve provided in a gas passage of the gas combustion device and a plurality of thermal fuses installed in the gas combustion device. The thermal fuses are connected in series to form a fuse circuit, and the fuse circuit is connected to a coil of the relay. The contacts of this relay are incorporated in a solenoid valve drive circuit. When the temperature of the gas combustion device rises abnormally due to idle heating, etc., the temperature fuse is blown and the fuse circuit is opened, so the relay coil is de-energized and the relay contact is turned off, and the solenoid valve drive circuit Open. As a result, the solenoid valve is closed, the gas supply to the gas combustion device is stopped, and safety is ensured.

[0003]

In the above configuration, even if the fuse circuit is short-circuited to the ground or two portions of the fuse circuit are short-circuited to each other, the relay contact is kept on, and the solenoid valve is turned on. In some cases, the open state is maintained, and the gas supply may be continued even if the fuse circuit does not function properly. In a recent safety device, a fuse circuit is constituted by a large number of wire elements. Each line element incorporates one or two fuses. Connectors are provided at both ends of each line element, and the line elements are connected in series via the connectors. As described above, connecting a large number of wire elements to the connector facilitates wiring work in the gas combustion device. However, in this case, gas supply is maintained even if the fuse circuit does not function properly due to incorrect connection of the connector. This is because the thermal fuse has a resistance value of substantially zero, and the relay contacts are kept on and the solenoid valve is kept open as long as the fuse circuit forms a closed loop even if erroneously connected. It is.

[0004]

According to a first aspect of the present invention, there is provided a safety device for a combustion device, comprising (a) a plurality of wire elements electrically connected to each other.
Ri, each of these lines elements, have a predetermined resistance value with including thermal fuse that will be placed in the combustion device, the electrical
Connection is made normally, and
A fuse circuit that should have a resistance value, and (b) all of the fuse circuits connected to the fuse circuit.
A detection voltage generating circuit for generating a detection voltage corresponding to the actual combined resistance value of the body; and (c) receiving a detection voltage different from a predetermined detection voltage to be generated corresponding to the predetermined combined resistance value. And control means for stopping the supply of fuel to the combustion device when the fuel is supplied. According to a second aspect of the present invention, in the safety device for a combustion apparatus according to the first aspect , the electrical connection is provided at both ends of each wire element.
A connector for connection is mounted . According to a third aspect of the present invention, in the safety device for a combustion apparatus according to the second aspect, the plurality of wire elements are connected in series with each other via a connector. According to a fourth aspect of the present invention, in the safety device for a combustion device according to the second aspect, the plurality of wire elements are connected in parallel with each other via a connector. According to a fifth aspect of the present invention, in the safety device for a combustion apparatus according to the first to fourth aspects, each of the wire elements is configured by incorporating a thermal fuse and a resistor in series. The invention according to claim 6 is the safety device for a combustion device according to any one of claims 1 to 5, further comprising a connector connected to both ends of the fuse circuit, a connector connected to the detection voltage generation circuit, and a ground. And a connector at one end of the fuse circuit is connected to a connector on the detection voltage generating circuit side, and a connector at the other end of the fuse circuit is connected to a connector on the ground side. The invention according to claim 7 is the safety device for a combustion device according to any one of claims 1 to 6, further comprising a normally closed solenoid valve provided in a fuel passage of the combustion device, and a drive circuit for opening the solenoid valve. A microcomputer is used as the control means. When the actual detection voltage matches the predetermined detection voltage, the microcomputer outputs an ON command signal to the drive circuit to open the solenoid valve. At a different time, an off command signal is output to the drive circuit to close the solenoid valve. The invention according to claim 8 is a combustion apparatus, comprising: (a) a casing containing a burner; and (b) a plurality of wire elements electrically connected to each other.
Ri, each of these lines elements, have a predetermined resistance value with including thermal fuse that will be installed in the casing,
As a result of the above electrical connection being made normally,
A fuse circuit should have a predetermined combined resistance value, the fuse circuit all connected to the (c) the fuse circuit
A detection voltage generation circuit for generating a detection voltage corresponding to the actual combined resistance value of the body; and (d) receiving a detection voltage different from a predetermined detection voltage to be generated corresponding to the predetermined combined resistance value. And control means for stopping the supply of fuel to the burner when the burner stops. According to a ninth aspect of the present invention, in the combustion device of the eighth aspect,
Connectors for the above electrical connections are provided at both ends of each wire element
Is mounted . A tenth aspect of the present invention is the combustion apparatus of the ninth aspect, wherein the plurality of wire elements are connected in series with each other via a connector. An eleventh aspect of the present invention is the combustion apparatus of the ninth aspect, wherein the plurality of wire elements are connected in parallel with each other via a connector. According to a twelfth aspect of the present invention, in the combustion apparatus of the eighth to eleventh aspects, each of the wire elements is configured by incorporating a thermal fuse and a resistor in series. According to a thirteenth aspect of the present invention, there is provided the combustion apparatus of the eighth to twelfth aspects, further comprising a connector connected to both ends of the fuse circuit, a connector connected to the detection voltage generation circuit, and a connector connected to the ground, A connector at one end of the fuse circuit is connected to a connector on the detection voltage generation circuit side, and a connector at the other end of the fuse circuit is connected to a connector on the ground side. According to a fourteenth aspect of the present invention, there is provided the combustion apparatus of the eighth to thirteenth aspects, further comprising a normally closed solenoid valve provided in a fuel passage to the burner, and a drive circuit for opening the solenoid valve. When the actual detection voltage matches the predetermined detection voltage, the microcomputer outputs an ON command signal to the drive circuit to open the solenoid valve, and at a different time, an OFF command to the drive circuit. It is characterized by outputting a signal and closing the solenoid valve.

[0005]

According to the first and eighth aspects of the present invention, if the thermal fuse of any one of the wire elements blows during abnormal heating of the combustion device, the resistance value of the entire fuse circuit, that is, the combined resistance of the plurality of wire elements is reduced.
Since the resistance value changes and the detection voltage deviates from the normal detection voltage, the control means cuts off the fuel supply. Also, one of the line elements is shorted to ground
Even if two line elements are short-circuited to each other, the resistance value of the entire fuse circuit changes and the detection voltage deviates from the normal detection voltage, so that the control means cuts off the fuel supply. Also, multiple thermal fuses can be distributed and placed.
Therefore, the detection range of abnormal heating can be expanded. Further
In the design stage, the electrical connection status of
Try various circuit configurations by changing the resistance of wire elements
And a functional circuit design can be performed.
At the manufacturing and assembly stage, if there is any incorrect wiring,
The actual combined resistance value changes depending on the state of
The incorrect wiring part by the combined resistance value at the time
Can be quickly adjusted and productivity can be improved. In the inventions of claims 2 to 4 and 9 to 11, the ends of each wire element are
Connector is installed, so connection between wire elements is easy.
You can simply do it. When connector erroneous connection, changes the resistance value of the fuse circuit, the detection voltage is out of the detection voltage of the normal connection, the control means interrupts the fuel supply. According to the fifth and twelfth aspects of the present invention, even when two portions of the line element of the fuse circuit are short-circuited, the resistance value of the fuse circuit changes and the detection voltage deviates from the detection voltage at the time of normal connection. Shut off supply. According to the sixth and thirteenth aspects, the fuse circuit can be easily connected to the detection voltage generation circuit and the ground via the outlet. According to the seventh and fourteenth aspects of the present invention, the control of the drive circuit of the normally-closed solenoid valve using the microcomputer can reliably perform the control of stopping the fuel supply.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the gas combustion device 10 (combustion device)
Location) has a heat exchanger 12 which receives the flame of the gas burner 11 and the burner 11. A normally closed solenoid valve 15 (valve) is provided in a gas passage 13 (fuel passage) connected to the gas burner 11. In addition, the gas combustion device 10
, A plurality of, for example, five thermal fuses 21 to 25 are installed at different places.

[0007] As shown in FIG.
To 25 form a fuse circuit 20. More specifically, the fuse circuit 20
Is configured by connecting three line elements 26 to 28 (series circuit unit) in series. A pair of connectors 26a and 26b are connected to both ends of the wire element 26, and connectors 27a and 27b are connected to both ends of the wire element 27, and connectors 28a and 28b are connected to both ends of the wire element 28, respectively. . The line element 26 has two thermal fuses 2
1, 2 and a resistor R1 interposed therebetween are connected in series with each other. Similarly, one thermal fuse 23 and a resistor R2 are connected in series to the line element 27, and the line element 28
Are connected in series with two thermal fuses 24 and 25 and a resistor R3 interposed therebetween.

The above three wire elements 26 to 28 are correctly connected in series as shown in FIG. That is, the connector 26
b and 27a are connected to each other, the connectors 27b and 28a are connected to each other, the connector 26a is located at one end of the fuse circuit 20, and the connector 28b is located at the other end of the fuse circuit 20.

The fuse circuit 20 is connected to a detection voltage generation circuit 30. The detection voltage generation circuit 30 has a pair of resistors Ra and Rb connected in series between the constant voltage source Vcc and the ground. The detection voltage generation circuit 30 further includes a detection-side connector 31 connected to a connection point between the resistors Ra and Rb. In the correct connection state, the connector 26a at one end of the fuse circuit 20 and the detection-side connector 31 are connected, and the connector 28b at the other end of the fuse circuit 20 is connected to the ground-side connector 32.

The voltage at the connection point between the resistors Ra and Rb, that is, the voltage at one end of the fuse circuit 20 is a detection voltage Vd.
Provided as This detection voltage Vd is input to the microcomputer 40 (control means) via an analog / digital converter (not shown). The reference voltage Vr from the reference voltage generation circuit 50 is also input to the microcomputer 40 via an analog-to-digital converter. The reference voltage generating circuit 50 includes a fixed resistor R connected in series between the constant voltage source Vcc and the ground.
c and a variable resistor Rd. These resistors Rc, Rd
Is provided as the reference voltage Vr. The microcomputer 40 controls the solenoid valve 15 via the drive circuit 60 based on the detection voltage Vd and the reference voltage Vr.

In the above configuration, the fuse circuit 20 is in the correct connection state and all the thermal fuses 21
When .about.25 is normal, the resistors R1, R2, and R3 are in series with each other, and are in parallel with the resistor Rb of the detection voltage generation circuit 30. Therefore, the fuse circuit 2
The combined resistance value Rx of 0 can be expressed by the following equation. Rx = R1 + R2 + R3 (1) The detection voltage Vd corresponding to the resistance value Rx of the fuse circuit 20 can be expressed by the following equation. Vd = Vcc · Ry / (Ra + Ry) (2) where Ry is a combined resistance of the resistance value Rx of the fuse circuit 20 and the resistance Rb of the detection voltage generation circuit 30, and can be expressed by the following equation. Ry = Rb · Rx / (Rb + Rx) (3) The reference voltage Vr is set to be equal to the detection voltage Vd in the above equation (2) by adjusting the variable resistor Rd.

The microcomputer 40 compares the detection voltage Vd with the reference voltage Vr, and when they match (when the difference between the two is within a small allowable range), the fuse circuit 20 is connected to the correct connection state. It is determined that all the thermal fuses 21 to 25 are normal, and an ON command signal is output to the drive circuit 60. As a result, the solenoid valve 15 is turned on to open, and the state in which gas can be supplied to the burner 11 is maintained.

When the temperature of the gas combustion device 10 rises due to idle heating or the like, at least one of the temperature fuses 21 to 25 is blown, and the fuse circuit 20 is opened.
In other words, the resistance of the fuse circuit 20 becomes infinite. At this time, the detection voltage Vd is expressed by the following equation and becomes higher than the reference voltage Vr. Vd = Vcc · Rb / (Ra + Rb) (4) At this time, the microcomputer 40 determines that the detection voltage Vd does not match the reference voltage Vr, and
An OFF command signal is output to 0, and the electromagnetic valve 15 is turned off and closed. As a result, the gas supply to the burner 11 is stopped, and safety can be ensured.

Further, in this embodiment, the microcomputer 40 can detect a short circuit of the fuse circuit 20. More specifically, for example, when the vicinity of both ends of the thermal fuse 21 is short-circuited to the ground, the resistances R1, R2, R3
Is canceled, the resistance value Rx of the fuse circuit 20 becomes substantially zero, and the detection voltage Vd drops to the ground level. At this time, the microcomputer 40 detects a mismatch between the detected voltage Vd and the reference voltage Vr, and closes the solenoid valve 15 as described above.

Similarly, when the both ends of the thermal fuses 22 and 23 are short-circuited to the ground, the resistors R2 and R3 are canceled, and when the thermal fuse 24 is short-circuited to the ground, the resistor R3 is canceled. In any case, the resistance value Rx of the fuse circuit 20 is reduced, and the detection voltage Vd is reduced. Therefore, the detection is performed by the microcomputer 40 and the solenoid valve 15 is closed. Although a short circuit to the ground near both ends of the thermal fuse 25 cannot be detected in the present embodiment, the thermal fuse 25 and the connector 2
8b may be provided with a resistor.

Also, in the fuse circuit 20, even when any two of the line elements 26, 27, and 28 are short-circuited, the resistance value Rx of the fuse circuit 20 is reduced.
As a result, the detection voltage Vd is reduced, so that the short circuit is also detected by the microcomputer 40, and the solenoid valve 15 is closed.

In this embodiment, a plurality of line elements 26, 27,
28, there is a possibility that an erroneous connection of the connector may occur. In the case of this misconnection, the microcomputer 4
0 can be detected. For example, as shown in FIG.
Are incorrectly connected to each other, and the connector 26b of the wire element 26 and the connector 28a of the wire element 28
Is incorrectly connected, the resistance value Rx of the fuse circuit 20 is represented by the following equation, and is smaller than that in the normal connection state (see equation (1)). Rx = R1 + R3 (5) Accordingly, similarly to the above-described short circuit between the line elements 26 to 28, the detection voltage Vd decreases, and the microcomputer 40 detects this and closes the solenoid valve 15. FIG. 4
As shown in FIG.
32 are incorrectly connected to each other, and a connector 26a of the wire element 26,
If the connector 28b of the wire element 28 is erroneously connected, the detection voltage Vd is reduced, so that the solenoid valve 15 is closed.

In the above embodiment, the microcomputer 40 does not have to input the reference voltage Vr. In this case, the reference voltage Vr is stored in the internal memory of the microcomputer 40. In the above embodiment,
The resistors R1, R2, and R3 may have different resistance values. In this case, the resistance value Rx of the fuse circuit 20 is different and the detection voltage Vd is different depending on various modes of short-circuiting and erroneous connection between the line elements. Therefore, in the microcomputer 40, depending on the level of these detection voltages,
The mode of the abnormality can be specified. In this case, the microcomputer can also display the failure mode on the display device.

FIG . 5 shows another embodiment of the present invention. In the figure, components corresponding to those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. In the embodiment of FIG. 5, the fuse circuit 70 has a plurality of, for example, four connectors 70a connected to the detection voltage generating circuit 30, and four grounded connectors 70b. Between the pair of connectors 70a and 70b, connectors 71a and 71b are provided at both ends.
Are connected in parallel with each other. Each line element 71 is connected in series with a thermal fuse 72 and a resistor R5. Also in this case, the four resistors R5 may be different from each other.

FIG. 6 shows a reference example relating to the present invention.
In this reference example , the fuse circuit 80 includes one line element 85.
(Series circuit unit). This line element 85
, Four thermal fuses 81, 82, 83, 84 are connected in series in this order, and a resistor R6 is interposed between the thermal fuses 82, 83 in series. Line element 85
Are provided with a pair of connectors 85a and 85b at both ends. In this reference example , when the portion between the resistor R6 and the connector 85a is short-circuited to the ground, the resistor R6 is canceled from the resistance value of the fuse circuit 80. Can be. Also, when a portion between the resistor R6 and the connector 85a and a portion between the resistor R6 and the connector 85b are short-circuited, the resistor R6 is canceled from the resistance value of the fuse circuit 80. To close the solenoid valve. Note that the resistor R6
A resistor may be interposed between the thermal fuse 84 and the connector 85b so that a short circuit to the ground between the connector and the connector 85b can be detected. The present invention is not limited to the above embodiments, and various modes are possible. For example, a comparator may be used instead of a microcomputer.

[0021]

According to the first and eighth aspects of the present invention, when any one of the plurality of places where the thermal fuses are installed is abnormally heated, the fuel is discharged.
By shutting off the supply, safety and reliability can be improved. Also, multiple thermal fuses can be distributed
With this, the detection range of abnormal heating can be expanded. Temperature hue
Not only when the fuse is blown or when the fuse circuit is short-circuited,
In the event of miswiring of wire elements, fuel supply is stopped to ensure safety and reliability.
Reliability can be improved. Furthermore, during the design phase,
The number of wire elements and the resistance of each wire element
Various circuit configurations can be tried by modifying
Circuit design can be performed. In the manufacturing and assembly stage,
If there is a miswiring, the miswiring depends on the actual combined resistance value.
Parts can be identified and quickly reworked,
Productivity can be improved. In the inventions of claims 2 to 4 and 9 to 11 , connectors are mounted on both ends of each wire element.
The connection between the line elements can be easily performed. Even when the connector is erroneously connected, the fuel supply is shut off, so that the reliability of the safety device can be further improved. Claim 5,
According to the twelfth aspect, even when two portions of the line element of the fuse circuit are short-circuited with each other, the fuel supply is reliably shut off. According to the sixth and thirteenth aspects, the fuse circuit can be easily connected to the detection voltage generation circuit and the ground via the outlet. In the invention of claims 7 and 14,
Stop control of fuel supply can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an entire safety device according to the present invention.

FIG. 2 is a diagram schematically showing an installation state of a solenoid valve and a thermal fuse for a gas combustion device.

FIG. 3 is a circuit diagram showing an aspect of incorrect connection of a connector in the safety device of FIG. 1;

FIG. 4 is a circuit diagram showing another mode of the incorrect connection of the connector of the safety device.

FIG. 5 is a diagram showing another embodiment of the fuse circuit of the safety device.

FIG. 6 is a diagram showing a reference example of a fuse circuit of the safety device.

[Explanation of symbols]

 10 ... gas combustion equipment(Combustion device)  13 ... gas passage(Fuel passage)  15… Solenoid valve(valve)  Reference Signs List 20 fuse circuit 21 to 25, 72, 81 to 84 thermal fuse 26 to 28, 71, 85 line element (series circuit part) 30 detection voltage generation circuit 40 control means (microcomputer) 26a, 26b, 27a , 27b, 28a, 28b, 3
1, 32, 70a, 70b, 71a, 71b, 85a,
85b ... connectors R1 to R6 ... resistance Vd ... detection voltage

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-2845 (JP, A) JP-A-5-66013 (JP, A) Jikai Sho 61-88433 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) F23N 5/24 113 F23N 5/02 310 H01H 37/76

Claims (14)

(57) [Claims] (A) a plurality of wires electrically connected to each other;
Consists element, have a predetermined resistance value with each of these lines element comprises a thermal fuse that will be placed in the combustion device
And the above electrical connection is made normally,
A fuse circuit should have a predetermined combined resistance value and, (b) the is connected to a fuse circuit all the fuse circuit
A detection voltage generating circuit for generating a detection voltage corresponding to the actual combined resistance value of the body; and (c) receiving a detection voltage different from a predetermined detection voltage to be generated corresponding to the predetermined combined resistance value. And a control means for stopping the supply of fuel to the combustion device when the combustion device has stopped. 2. The electrical connection of each of the line elements is provided at both ends.
The safety device for a combustion device according to claim 1, wherein a connector for the combustion device is mounted . 3. The safety device according to claim 2, wherein the plurality of wire elements are connected in series with each other via a connector. 4. The safety device according to claim 2, wherein the plurality of wire elements are connected to each other in parallel via a connector. 5. A safety device for a combustion device according to claim 1 , wherein each of said wire elements is constituted by incorporating a thermal fuse and a resistor in series. And a connector connected to both ends of the fuse circuit, a connector connected to the detection voltage generation circuit, and a connector connected to the ground, wherein a connector at one end of the fuse circuit is connected to the detection voltage generation circuit side. And a connector on the other end of the fuse circuit is connected to a connector on the ground side.
A safety device for a combustion device according to any of the preceding claims. 7. Further, a normally closed solenoid valve provided in the fuel passage of the combustion apparatus, and a driving circuit for operating open the solenoid valve, using a microcomputer as a control means, the microcomputer is in fact When the detected voltage is equal to the predetermined detected voltage, an ON command signal is output to the drive circuit to open the solenoid valve, and at a different time, an OFF command signal is output to the drive circuit to close the solenoid valve. A safety device for a combustion device according to any one of claims 1 to 6. And (b) a plurality of wire elements that are electrically connected to each other.
Ri, each of these lines elements, have a predetermined resistance value with including thermal fuse that will be installed in the casing,
As a result of the above electrical connection being made normally,
A fuse circuit should have a predetermined combined resistance value, the fuse circuit all connected to the (c) the fuse circuit
A detection voltage generation circuit for generating a detection voltage corresponding to the actual combined resistance value of the body; and (d) receiving a detection voltage different from a predetermined detection voltage to be generated corresponding to the predetermined combined resistance value. And a control means for stopping the supply of fuel to the burner when the combustion is stopped. 9. Both ends of each wire element are connected to the electrical connection.
9. The combustion device according to claim 8, wherein a connector for mounting is mounted . 10. The apparatus according to claim 9, wherein the plurality of wire elements are connected to each other in series via a connector.
The combustion device according to claim 1. 11. The device according to claim 9, wherein the plurality of wire elements are connected to each other in parallel via a connector.
The combustion device according to claim 1. 12. The combustion device according to claim 8 , wherein each of the wire elements is configured by incorporating a thermal fuse and a resistor in series. And a connector connected to both ends of the fuse circuit, a connector connected to the detection voltage generation circuit, and a connector connected to the ground, wherein one end of the fuse circuit is connected to the detection voltage generation circuit side. And a connector at the other end of the fuse circuit is connected to a connector on the ground side.
13. The combustion device according to any one of 12 above. 14. further comprising a normally closed solenoid valve provided in the fuel passage to the burner, and a drive circuit for operating open the solenoid valve, using a microcomputer as a control means, the microcomputer is in fact When the detected voltage is equal to the predetermined detected voltage, an ON command signal is output to the drive circuit to open the solenoid valve, and at a different time, an OFF command signal is output to the drive circuit to close the solenoid valve. The combustion device according to any one of claims 8 to 13.