JP3300136B2 - Capacity switching type combustion device with CO safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater and a bath kettle.
The present invention relates to a capacity switching type combustion device with an O safety device.

[0002]

2. Description of the Related Art As a combustion apparatus, a general capacity switching type water heater with a CO safety device is disclosed in Japanese Utility Model Laid-Open No. 63-173656. This device is designed to remove CO2
The concentration is detected by a CO sensor, and when the detected CO concentration exceeds a predetermined value, a CO detection signal is output from a CO detection circuit,
Using this signal, safety control for CO is performed.

[0003] In this apparatus, attention is paid to the fact that a larger amount of CO gas is generated at the time of switching the combustion capacity than at the time of normal combustion, and at the time of switching the capacity, the CO sensor detects this large amount of CO gas. In order to prevent abnormal control from being performed, a timer is operated for a predetermined time when the switching of the combustion capacity is detected, and the timer operation time is independent of the magnitude of the detection signal from the CO sensor. C
The output of the CO detection signal from the O detection circuit is stopped.

[0004]

However, this type of apparatus stops outputting a CO detection signal from the CO detection circuit when the combustion capacity is switched, and when the normal combustion operation other than when the combustion capacity is switched, the CO detection signal is not output. The configuration is such that the CO safety operation is not performed unless the sensor output exceeds a predetermined value. When a failure such as disconnection occurs in the CO sensor, this failure is not detected, and in this case, a large amount of CO gas is used. However, since the output corresponding to the CO concentration cannot be obtained from the CO sensor side even if the
There is a problem that the detection signal is not output and the CO safety operation does not operate, resulting in a very dangerous state.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent abnormal control from being performed by the output of a CO sensor when the combustion performance is switched, and to disconnect the CO sensor. Another object of the present invention is to provide a capacity switching type combustion device with a new CO safety device having a different configuration from the conventional example that can detect a failure such as the above.

[0006]

The present invention is configured as follows to achieve the above object. That is, the present invention is the ability switching means of the burner combustion, and the CO sensor for detecting CO in the exhaust gas, the direction of increasing CO concentration reference value of CO output value of the CO sensor is provided in advance
Possess a CO safety device to shut off the fuel valve provided in the fuel supply passage to the burner when it exceeds the, the CO safety device before
The output value of the CO sensor is compared with the CO reference value.
A comparison / judgment unit is provided.
Output value exceeds the CO reference value in the direction of increasing CO concentration
The fuel valve is shut off when it is determined that
In a capacity switching type combustion device with a CO safety device, a capability switching detection unit for detecting a capability switching operation of the capability switching means of the burner combustion, and when the capability switching detection unit detects a capability switching of the burner combustion, CO
Force open drive for a predetermined time the fuel valve of CO detection signal from the sensor as an operation input, and forced valve drive circuit to force drive for closing the fuel valve when the CO detection signal as the operation input is not obtained, a combustion device Other than the CO sensor constituting
Detects abnormal operation of a predetermined device element and detects the abnormal operation.
Is detected, the CO concentration is lower than the CO reference value.
An abnormal signal with a large value in the increasing direction is compared with the CO safety device.
And self safety circuit applied to compare determination unit, the provided the CO
Safety devices are added from the self-safety circuit by the comparison
The value of the abnormal signal increases the CO reference value and increases the CO concentration
Shuts off the fuel valve when it is determined that the vehicle has crossed the direction
It is configured as characterized by.

[0007]

In the present invention having the above-described structure, when the burner combustion performance is switched, the switching of the combustion performance is detected by the performance switching detector. Based on the detection of the switching of the combustion capacity, the forcible valve drive circuit receives a CO detection signal from the CO sensor, and when the CO detection signal is being output from the CO sensor, uses the CO detection signal as an operation input for a predetermined time. The fuel valve in the fuel supply passage is forcibly opened to prevent a problem that the CO safety device shuts off the fuel valve and stops the combustion due to the temporary generation of a large amount of CO gas when the combustion capacity is switched. I do.

[0008] If the CO sensor has a failure such as a disconnection at the time of switching the combustion capacity, no CO detection signal is output from the CO sensor. At this time, the forced valve drive circuit does not receive an operation input, so that no operation input is applied. As a result, it is determined that the CO sensor has failed, and as a result of shutting down the fuel valve, the combustion is stopped, thereby preventing the combustion operation from being performed while the CO sensor has failed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a block configuration of an embodiment of the apparatus of the present invention. In FIG. 1, a gas supply passage 3 is connected to a burner 1 of a combustion device such as a water heater, a bath kettle, or a combustion type heater via a solenoid valve 2 for switching capacity. A fuel valve 4 such as an electromagnetic valve is provided.

The gas supply passage 3 on the downstream side of the fuel valve 4 is branched into a first passage 5 and a second passage 6 and connected to the burner 1, and the inlet of the first passage 5 is connected to the electromagnetic valve. The solenoid valve 2 is opened and closed by a capacity changeover switch 7 which is manually or automatically operated.

A CO sensor 8 for detecting CO in the exhaust gas generated by the combustion of the burner 1 is provided on the exhaust side of the combustion device. Is connected to the base end side.

A comparison judging unit 13 is connected to the normally closed contact 12 side of the operation changeover switch 10. The comparison determination unit 13 is provided with a reference value that is a reference for determining the danger of CO in the exhaust gas. The comparison determination unit 13 outputs the output (C
O detection signal level) and the reference value, and when the sensor output value exceeds the reference value, a high level (hereinafter referred to as H
And outputs a low level signal (hereinafter referred to as L level) when the sensor output value is equal to or less than the reference value. The alarm unit 14 sounds a buzzer only when an H-level signal is added from the comparison / determination unit 13,
Alternatively, the danger of the CO concentration is displayed on the display unit of the remote controller (not shown) of the control device of the combustion device, and a warning is given that the state of generation of CO is in a danger state.

The valve drive section 15 drives the fuel valve 4 to be shut off when an H level signal is applied from the comparison / determination section 13;
The combustion of the burner 1 is stopped, and the fuel valve 4 is kept open when an L-level signal is applied from the comparison / determination unit 13.

A forced energizing circuit 17 is connected to the normally open contact 16 side of the operation changeover switch 10.
Reference numeral 17 denotes a state in which the movable piece 11 of the operation changeover switch 10 is switched to the normally open contact 16 side. When a CO detection signal is applied from the CO sensor 8, a valve opening drive current is forcibly supplied to the fuel valve 4. Then, the fuel valve 4 is kept open. The forced energizing circuit 17 is a movable piece of the operation changeover switch 10.
If the CO detection signal from the CO sensor 8 is not applied or is interrupted while the terminal 11 is connected to the normally open contact 16, the energization of the valve opening drive current to the fuel valve 4 is forcibly stopped. Then, the fuel valve 4 is forcibly shut off to stop burner combustion.

The changeover switch signal of the capability changeover switch 7 is applied to a capability changeover detection unit 18.
When detecting the switching of the combustion capacity in response to the switch signal, the capacity switching detection unit 18 operates the timer of the timer circuit 20 for a predetermined time. The timer circuit 20 drives the coil 21 only during the operation period of the timer, and switches the movable piece 11 of the operation changeover switch 10 from the normally closed contact 12 side to the normally open contact 16 side to maintain it. The operation changeover switch 10 opens the movable piece 11 only during the period when the timer is operating.
Side, and after the timer expires, the movable piece
11 is switched to the normally closed contact 12 side and maintained.

The self-safety circuit 22 detects an abnormal state of each part of the combustion device by itself. The self-safety circuit 22 is provided in the combustion device, and is used as a device element constituting the combustion device, such as a temperature fuse or a burner. When a signal from a frame rod electrode (flame detection sensor) or the like to be installed is received, for example, when an off signal is applied from a thermal fuse, it is detected that an abnormal heating state of the device has occurred, and when an off signal is applied from the frame rod electrode. A misfire abnormality is detected, an H-level signal is output as an abnormal signal, and the H-level signal is applied to the comparison / determination unit 13 via the operation changeover switch 10.

In this embodiment, the comparison / determination section 13, the alarm section 14, and the valve drive section 15 constitute a CO safety device, and a capacity switching detection section 18, a timer circuit 20, a coil 21, and an operation switching switch.
10 and the compulsory energizing circuit 17 constitute a compulsory valve drive circuit.

This embodiment is configured as described above.
Next, the operation will be described based on the configuration diagram of FIG. 1 and the flowchart of FIG. In the operating state of the solenoid valve 2 shown in FIG. 1, the fuel gas supplied from the gas supply passage 3
Is supplied to the burner 1 through the passage 6 of the burner 1.
Is burning at low capacity. In the combustion operation state of the burner 1, the CO sensor 8 detects CO in the exhaust gas momentarily and outputs a CO detection signal.

In this combustion operation state, the movable piece 11 of the operation changeover switch 10 is connected to the normally closed contact 12 side.
The sensor output of the O sensor 8 is applied to a comparison judging unit 13. In step 101 of the flowchart of FIG. 2, the comparison / determination unit 13 compares the reference value given in advance with the level of the CO detection signal (sensor output value), and when the sensor output value exceeds the reference value, the H level becomes high. Output a signal.

When this H level signal is output, a fuel valve stop signal (valve closing drive signal) is applied to the fuel valve 4 from the valve drive unit 15 in step 108, and the fuel valve 4 is shut off.
On the other hand, a warning of a dangerous state of the CO concentration is issued by the alarm unit 14 based on the H level signal from the comparison judgment unit 13.

When the sensor output value is equal to or less than the reference value, an L-level signal is output from the comparison / determination unit 13 by comparing the reference value and the CO sensor output value in the comparison / determination unit 13. The drive unit 15 keeps the fuel valve 4 open, and the combustion operation is continued. Then, in the continuous state of the combustion operation, it is determined in step 102 whether or not the burner has been switched, that is, whether or not the combustion capacity has been switched. When the capacity changeover switch 7 is operated and the inlet of the first passage 5 is opened by the solenoid valve 2, the fuel gas from the gas supply passage 3 passes through both the first passage 5 and the second passage 6. As a result, fuel gas is supplied to the burner 1, and the burner 1 burns in a large capacity state. Thus, burner 1
Is switched (switching of the combustion surface and the number of burners used), the signal of the switch 7 is applied to the capacity switching detection unit 18, and the combustion switching is performed by the capacity switching detection unit 18. Is detected.

Then, in step 103, the timer circuit
The timer operation of 20 starts, and the driving of the coil 21 causes the movable piece 11 of the operation changeover switch 10 to be switched to the normally open contact 16 side in step 104. This operation changeover switch 10
By this switch, the CO detection signal output from the CO sensor 8 is applied to the forced energizing circuit 17. In step 105, the forced energizing circuit 17 determines whether or not a CO detection signal has been applied from the CO sensor 8. CO sensor 8
When the CO detection signal is supplied from the control unit, it is determined that there is no abnormality such as disconnection in the CO sensor 8, the forced open drive current is supplied to the fuel valve 4, and the fuel valve 4 is maintained in the open state. On the other hand, when the CO sensor 8 has failed due to disconnection or the like, no CO detection signal is output from the CO sensor 8. When it is confirmed that the sensor output is not applied or when the output of the CO sensor is interrupted on the way, the forced energizing circuit 17 determines that an abnormality such as disconnection has occurred in the CO sensor 8, and sends the signal to the fuel valve 4. The supply of the forcibly opening drive current is stopped, and the fuel valve 4 is shut off and the combustion of the burner 1 is stopped in the same manner as in steps 108 and 109.

When the timer operation time of the timer circuit 20 elapses, the driving of the coil 21 is stopped, resulting in step 107
Then, the movable piece 11 of the operation changeover switch 10 is switched to the normally closed contact 12 side, and the switching state is maintained. And
The operations after step 101 in the flowchart are repeatedly performed.

During the combustion operation, the self-safety circuit 22 is in an off state of the thermal fuse (fuse disconnection state) provided in the combustion apparatus, and an off signal of the flame rod electrode (not shown) (burner misfire state). When such an abnormality is detected, an H-level signal is output, and this H-level signal is applied to the comparison / determination unit 13 via the operation changeover switch 10. The comparison / determination unit 13 compares the reference value with the H-level signal. At this time, since the H-level signal value is larger than the reference value, the H-level signal is directly applied to the valve drive unit 15 to shut off the fuel valve 4.

At the same time, an H level signal is also input to the timer circuit, and the timer circuit is reset. Therefore, even when the operation changeover switch 10 is at the normally open contact 16 side during the capacity switching, this is not changed to the normally closed contact 12. Therefore, the H level signal is applied to the valve drive unit 15 to shut off the fuel valve 4.

According to the present embodiment, when the combustion capacity is switched, the forced energizing circuit 17 operates to keep the fuel valve 4 open for a predetermined timer operation time. Even if the amount of generated CO gas is large, it is possible to solve the problem that the CO safety device operates and the fuel valve 4 is shut off. Moreover, this fuel valve 4
Is limited to a short time in which the generation of CO gas temporarily increases due to the switching of the combustion capacity, and when the short timer operation time elapses, the operation changeover switch 10
Is the CO that performs normal CO safety operation from the forced energizing circuit 17 side
Switching to the comparison / determination unit 13 side of the safety device performs the CO safety operation, so that safety against CO gas is not impaired.

When the combustion performance is switched, the forced energizing circuit 17 determines whether or not there is an abnormality such as disconnection of the CO sensor 8 based on the presence or absence of the sensor output of the CO sensor 8. When a failure occurs, the abnormality is alerted by the alarm unit 14 and the fuel valve 4 is immediately shut off, so that the combustion operation is not continued with the CO sensor 8 having a failure and the safety against CO gas is remarkably improved. Can be up.

Further, in this embodiment, the self-safety circuit 22
Operation, the thermal fuse in the combustion device blows,
When the misfire is confirmed, the fuel valve 4 is automatically shut off, so that the safety is secured even in the case of a device abnormality other than the CO gas.

The present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, the self-safety circuit of the above example is configured to output a high-level signal when the thermal fuse is blown or an off signal from the frame rod electrode is detected. Outputs a high level signal when an off signal (water stop signal) is output from a flow sensor (water volume sensor) or the like of the device element or an off signal is applied from a remote controller of the control device. Alternatively, the fuel valve 4 may be shut off.

Further, in the above-described embodiment, an example in which the combustion capacity is switched in two stages has been described. However, the number of stages in which the combustion capacity is switched may be three or more, which is arbitrarily set according to the specifications.

Further, although the above-described embodiment has described the combustion apparatus using gas as a fuel, the combustion apparatus to which the present invention is applied is naturally applied to the apparatus using oil as fuel.

Further, the present embodiment has been described with respect to an operation example at the time of switching the combustion capacity. However, as an application example of the present invention, the present invention can also be applied to an operation at the time of ignition of the burner 1. In this case, the ignition state is detected by the ignition state detection unit,
When ignition of the burner 1 is detected by the ignition state detection unit, the timer circuit 20 is operated in the same manner as the capacity change detection unit 18 of the present embodiment, and the operation changeover switch 10 is changed from the normal CO safety operation state of the normal CO safety device. The fuel valve 4 is forcibly opened for a predetermined timer operation time by switching to the forced energizing circuit 17 side. It is known that the amount of generated CO gas also increases at the time of ignition as in the case of switching the combustion capacity.
The problem that the CO safety operation is activated upon detection by the sensor 8 and the fuel valve 4 is shut off every time ignition is performed can be similarly solved.

[0033]

According to the present invention, the fuel valve is forcibly opened by driving the forcible valve drive circuit for a predetermined time every time the combustion performance is switched by using the CO detection signal from the CO sensor as a drive input. As long as there is no abnormality such as disconnection in the CO sensor, when the combustion capacity is switched,
Since the fuel valve is automatically opened and maintained in that state, even if the amount of CO gas generated temporarily increases due to switching of the combustion capacity, the CO safety device operates and the fuel valve is shut off. It is possible to reliably eliminate the occurrence of a malfunction state in which the combustion of the burner is stopped.

Moreover, in the prior art, when the combustion capacity is switched, the output of the CO detection circuit is stopped to passively maintain the open state of the fuel valve, whereas in the present invention, the switching of the combustion capacity is detected. In such a case, the fuel valve is positively forcibly opened, so that the reliability of the opening operation of the fuel valve is improved.

Further, in the present invention, since the forced valve drive circuit is operated by using the CO detection signal of the CO sensor as an operation input, when the CO sensor fails due to disconnection or the like, the CO detection signal of the CO sensor is used as the operation input. As a result, the fuel valve is forcibly closed and driven by the forcible valve drive circuit. As a result, it is possible to prevent the malfunction that the combustion operation is continued while the CO sensor is broken due to disconnection or the like.
Gas safety is greatly enhanced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 burner 4 fuel valve 7 capacity changeover switch 8 CO sensor 10 operation changeover switch 13 comparison judgment section 14 alarm section 15 valve drive section 17 forced energizing circuit 18 capacity changeover detection section 20 timer circuit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-26439 (JP, A) JP-A-61-295425 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 5/24 107 F23N 5/24 113

Claims (1)

(57) [Claims] And 1. A burner combustion ability switching means, a CO sensor for detecting CO in the exhaust gas, increasing the reference value of the CO which the output value of the CO sensor is provided in advance of the CO concentration
And CO safety device to shut off the fuel valve provided in the fuel supply passage to the burner when it exceeds the pressure direction possess, the CO safety instrumentation
Is a ratio between the output value of the CO sensor and the reference value of the CO.
A comparison and judgment unit for comparing the CO
The output value of the sensor increases the CO reference value in the CO concentration increasing direction.
The fuel valve is shut off when it is determined that the
In a capacity switching type combustion apparatus with a CO safety device, a capacity switching detection unit that detects a capacity switching operation of the burner combustion capacity switching unit, and when the capacity switching detection unit detects a burner combustion capacity switching. A forced valve drive circuit for forcibly opening the fuel valve for a predetermined time with a CO detection signal from the CO sensor as an operation input, and forcibly closing the fuel valve when a CO detection signal as an operation input is not obtained; The CO sensor constituting the combustion device
Abnormal operation of predetermined device elements other than
When an abnormal operation is detected, the value of C is higher than the reference value of CO.
An abnormal signal with a large value of O concentration increasing in the direction of CO
A self-safety circuit to be added to the comparison and judgment unit of the device ,
The CO safety device has a self-safety circuit
The value of the abnormal signal added from
When it is determined that the concentration has been exceeded, the fuel
A capacity switching type combustion device with a CO safety device, characterized in that the valve is shut off .