JP2582521Y2 - Combustible gas detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustible gas detecting device, and more particularly to a combustible gas detecting device which measures an abnormal state by measuring the concentration of carbon monoxide in exhaust gas and activates a predetermined safety device. .

[0002]

2. Description of the Related Art Conventionally, an indoor type water heater (FE type) has been used.
Such a gas combustion device is known. In such a gas combustion device, the concentration of combustible gas such as carbon monoxide in exhaust gas is measured using a so-called contact combustion type detection element, and a predetermined safety device is activated. A flammable gas detection device is provided.

[0003] For example, the FE type water heater using an AC 100 V power supply is provided with a CO sensor having a contact combustion type detection element at an exhaust port portion of a main body of the FE type water heater. The abnormal state is detected by measuring the concentration of carbon monoxide, and the gas supply pipe leading to the burner is shut off by the solenoid valve.

That is, as shown in FIG. 9, in the CO sensor 1, a sensing element 2 disposed in an exhaust port portion that can contact exhaust gas is a temperature compensating comparison element (not shown), a fixed resistor and a movable resistor, and a bridge. When the sensing element 2 touches the exhaust gas, it generates heat in accordance with the concentration of carbon monoxide in the exhaust gas, and its resistance value changes. Is the sensor output V
s. Then, when this sensor output Vs exceeds a predetermined set value Vr,
Judging that the concentration of carbon monoxide in the exhaust gas has reached a dangerous state, an alarm signal is output and the gas supply source is shut off, preventing the accident of poisoning by filling the room with carbon monoxide. I have.

In such a flammable gas detection device, the sensor output Vs is compared with the predetermined fixed alarm level Vr as described above. Therefore, it is assumed that the sensor output Vs exceeds the alarm level Vr. It is necessary to surely set the zero-point reference value in a state where carbon monoxide as a criterion for determining whether or not carbon monoxide has not been detected.
The zero point reference value is set by adjusting the movable resistance of the CO sensor 1 in advance at the factory shipment stage so that the bridge circuit is in an equilibrium state.

[0006]

However, in the above-described conventional combustible gas detection device, the movable resistance of the CO sensor 1 is deviated from the adjustment position at the factory due to vibration or the like generated during use of the water heater. In such a case, the zero-point reference value in a state where carbon monoxide, which is a reference for determining whether or not the sensor output Vs has exceeded the alarm level Vr, has not been detected, becomes incorrect. Sensor output Vs including a serious error and predetermined alarm level V
r, the actual carbon monoxide concentration is at the alarm level Vr, but the alarm level V
r has not been reached, and there is a risk that a dangerous state may occur in which the predetermined safety device does not operate at all.

Further, in the contact-type detection element 2 of the CO sensor 1, the resistance value in a state where carbon monoxide is not detected may change due to aging or the like. Also, there is a possibility that the above-mentioned zero-point reference value will be out of order, causing the same inconvenience.

[0008] The present invention has been made in view of the above-mentioned points, and a zero-point reference value for generating an alarm is specially provided to a user.
Operation after the burner was extinguished
It is an object of the present invention to provide a highly safe and reliable combustible gas detection device that can be set as appropriate without being affected by combustible gas and that can monitor the concentration of combustible gas with high accuracy. .

[0009]

In order to achieve the above object, a flammable gas detection device according to the present invention is provided for detecting flammable gas contained in exhaust gas discharged from a gas combustion device having a burner.
In a combustible gas detection device that is detected by a contact combustion type detection element, exhaust gas after the burner extinguishes is discharged.
After the end of the post-fan operation for performing the burner operation, the output of the detection element is used as a sensor output when the burner is not in a combustion state.
A storage unit for storing a force as a zero-point reference value for generating an alarm, and, based on the stored output of the detection element , a reference value of the detection element after the fire is ignited.
The output was monitored as a sensor output when in the combustion state,
The output of the sensing element is to its characterized by including a determination unit that performs a predetermined alarm operation when a predetermined output or for a given concentration of the combustible gas.

[0010]

According to the present invention, as shown in the principle diagram of FIG. 1, the sensor output when the burner is not in a combustion state is a bar sensor.
After the fire extinguishes the fire extinguisher.
The output of the sensing element after the end of the sensing operation is stored in the storage means as a zero point reference value for generating an alarm, and
On the basis of the output of the sensing element, the burner will fire wearing after the fire fighting
The output of the detecting element after the fire is monitored by the judging means as a sensor output when the burner is in a combustion state, and the bar after the fire is extinguished.
A predetermined alarm operation is performed when the output of the detection element after the ignition of the fuel becomes equal to or higher than a predetermined output for a predetermined concentration of combustible gas. Therefore, exhaust from the gas combustion device
To detect the combustible gas in the exhaust gas emitted by the detection element
The zero point base of the detection element output to generate an alarm
The quasi-value will be any value as the ignited burner extinguishes.
Burner after fire extinguishing without special operation of
Is updated to the output of the sensing element when
Combustible gas in exhaust gas after subsequent burner ignition
The burner after the update is in a combustion state
The output of the sensing element when not present is used as the zero point reference value.
Will be. Moreover, the burner burns after the fire is extinguished.
Update of the zero point reference value to the output of the sensing element when not in the burning state
However, it is not just after the burner is extinguished,
Post-fan operation to extinguish the fire and exhaust the subsequent exhaust
Since it is performed after the work is completed, the updated 0-point reference value
However, the effect of residual combustible gas after the burner extinguishes
Absent.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. First, before explaining the embodiment according to the present invention,
In order to make it easier to grasp the characteristics of the idea,
About a gas combustion device having such a combustible gas detection device,
This will be described with reference to FIGS. And in this comparative example
In such a gas combustion device, as shown in FIG. 2, a fan 4 for supplying necessary air to the burner 5 is provided at a lower end portion of the water heater main body 3, and the air from the fan 4 and the air from the fan 4 are not shown. The gas from the gas supply pipe is sent to the burner 5 in the main body 3 to burn the gas.
In the heat exchanger 6 disposed above the burner 5, water sent from a water supply pipe (not shown) is heated to hot water of a predetermined temperature. The main body 3
An exhaust port 7 is provided at the upper end of the burner 5 so that a combustion gas containing a combustible gas such as carbon monoxide is exhausted from the burner 5. Further, at the upper end of the main body 3 and at a position where the combustion gas passes therethrough, a contact combustion type detection element 2 of a CO sensor 1 having the same configuration as the conventional one is provided.
Are arranged.

As shown in FIG. 3, a CO sensor drive circuit 11 is connected to the CO sensor 1,
The drive circuit 11 is connected to a water heater control circuit 12 composed of a microcomputer (CPU). further,
The water heater control circuit 12 is connected to a flow sensor 13 provided in a water supply pipe, and is connected to a reset switch 14 for canceling an alarm.
5, a fan drive circuit 16, a burner control circuit 17, and an electromagnetic valve 18 provided in the gas supply pipe are connected. In the drawing, reference numeral 19 denotes an AC 100 V power supply line,
Is a power supply line, and 21 is a signal line.

[0013] In such a combustible gas detection device,
As shown in FIG. 4, when the power supply of the water heater main body 3 is turned on by plugging an outlet into an AC 100V power supply, the CPU of the water heater control circuit 12 is activated to supply power to the CO sensor drive circuit 11 ( In step S1), a timer set for a predetermined time is started (step S2). When the timer has counted a predetermined time, it is determined that the bridge circuit of the CO sensor 1 has stabilized (step S3), the sensor output Vs at that time is read (step S4), and the memory 12a in the water heater control circuit 12 For example, by storing this in a RAM, a zero point reference value V ₀ for generating an alarm is set (step S).
5). Thus, the zero point reference value is set in a state where the burner 5 is not in a combustion state and no carbon monoxide is generated.

In this state, based on the signal from the flow sensor 13, it is determined whether or not the user has opened a water faucet (not shown) of the water heater main body 3 and whether water has flowed (step S6). Then, the burner 5 is ignited (step S7) and the fan 4 is rotated (step S8). As a result, the air from the fan 4 and the gas from the gas supply pipe burn in the burner 5, and in the heat exchanger 6 arranged above the burner 5, the water sent from the water supply pipe is removed. It can be heated to hot water at a predetermined temperature.

Thereafter, when it is determined from the signal from the flow sensor 13 that the user has closed the water tap of the water heater body 3 (step S9), the burner 5 is extinguished (step S10) and the fan 4 is stopped (step S10). Step S
11). Also, based on the signal from the flow sensor 13, it is determined that the user has not closed the faucet (step S9).
Occasionally, the concentration of carbon monoxide is monitored by the sensor output Vs from the CO sensor 1 and an alarm is issued when an abnormal state is equal to or higher than a predetermined concentration, and a solenoid valve 18 provided in the gas supply pipe is provided.
To extinguish the burner 5 (step S12).

That is, in step S12, as shown in detail in FIG. 5, the sensor output Vs from the CO sensor 1 is read (step S12a), and the read sensor output Vs and the zero-point reference value V are read. Difference Vs− from ₀
Take the V ₀ (step S12b), the difference Vs-V
₀ is determined in advance by comparing it with a predetermined alarm level Vr stored in, for example, the RAM of the memory 12a in the water heater control circuit 12 (step S12c). Then, when the direction of the difference _{Vs-V 0} is large, it actuates an alarm buzzer 15 (step S1
Along with 2d), the burner 5 is extinguished by shutting off the electromagnetic valve 18 provided in the gas supply pipe (step S1).
2e).

Thereafter, a reset switch 1 for releasing the alarm
4 is operated (step S12f), the operation of the alarm buzzer 15 is stopped (step S12f).
g), the water not boiled to the predetermined temperature continues to flow, and when it is determined that the reset switch 14 has not been operated (step S12f), the alarm buzzer 15 continues to operate. In addition, the difference V
When it is determined that s−V ₀ is smaller than the alarm level Vr (step S12c), the combustion of the burner 5 is maintained.

In the present comparative example, when the burner 5 burns, the combustion gas comes into contact with the detection element 2 of the CO sensor 1 disposed in the water heater main body 3, whereby the carbon monoxide in the exhaust gas is discharged. The concentration is monitored.

Therefore, in this comparative example, the movable resistance of the CO sensor 1 shifts from the adjustment position at the factory due to vibrations or the like generated during use of the water heater main body 3 and the zero-point reference value is deviated. Even when only the sensor output Vs including the value is output, the zero point reference value V for generating an alarm
_{Since 0} is set when the power of the water heater main body 3 is turned on, a new 0-point reference value V ₀ is set in a state including the deviation of the 0-point reference value. It has become. Then, the difference Vs-V ₀ between the sensor output Vs and the new zero point reference value V _0, since adapted to compare the warning level Vr corresponding to dangerous concentrations of carbon monoxide to a predetermined one The concentration of carbon oxide can be monitored with high accuracy, and the safety and reliability of the gas combustion device can be significantly improved.

Further, the contact detection element 2 of the CO sensor 1 in a state where carbon monoxide is not detected due to aging or the like.
Is changed, and thereafter, even when the resistance value of the detecting element 2 surely changes according to the carbon monoxide concentration, the outlet of the water heater main body 3 is periodically connected and disconnected. By periodically turning on the power supply, a new zero-point reference value V including the aging of the detection element 2 in a state where the above-described carbon monoxide is not detected is included.
_{Since 0} is set, the carbon monoxide concentration can be monitored with high accuracy without being affected by the aging of the sensing element 2 described above. However, upside down
In the comparative example described above, the outlet of the water heater main body 3 is connected and disconnected.
Power from the OFF state to the ON state,
It is possible to newly set the zero point reference value V ₀ of the CO sensor 1.
I couldn't do it and eventually plugged in and out the hot water heater 3
Operation that depends on the user becomes indispensable
I will.

The present invention has been made to solve the problems of the comparative example.
And the is the respective reference examples of FIGS. 6 and 7, the largest Japanese
The sign is, as is clear from the following explanation,
0 point reference value V ₀ which CO sensor 1 without using the special operation
It is to be newly set. 6 and 7, shows a combustible gas detection equipment according to the reference example of the present invention, respectively, power-on the setting of a new zero point reference value V ₀ described above, the water heater body 3 as described above Burner burning, not time
5 is performed after the fire is extinguished .

That is, in the case shown in FIG.
Is turned on, the CP of the water heater control circuit 12 is turned on.
U starts and supplies power to the CO sensor drive circuit 11 (step S1), and starts a timer set for a predetermined time (T minutes) (step S2). Then, when it is determined that the timer has counted the predetermined time (step S3), a series of processes from ignition to extinguishing of the burner 5 similar to steps S6 to S12 in FIG. 4 is performed (step S4). ).

If it is determined that the burner 5 is not in a combustion state (it is in a fire extinguishing state) in the above-described ignition and fire extinguishing processing (step S4), a timer is started again (step S5), and the extinguishing of the burner 5 is confirmed. (Step S
6) When the timer counts a predetermined time and it is determined that the sensor output Vs has stabilized (step S7), the sensor output Vs at that time (the burner 5 is in the fire-extinguishing state) is read (step S8), and this is controlled by the water heater control. Memory 12 in circuit 12
By storing the a, 0-point reference value V ₀ which is for generating an alarm is adapted to be set (step S
9). If it is determined that the burner 5 is ignited after the start of the timer (step S5) (step S6),
It is determined whether or not the water has been stopped again in the ignition and fire extinguishing process (step S4), and the subsequent fire extinguishing process is performed.

When it is determined from the signal from the flow sensor 13 that water has flowed after the setting of the zero point reference value V ₀ and before the timer time T in step S3 has elapsed (step S10). The processing after the ignition of the ignition and extinguishing processing (step S4) is performed.

[0025] Thus, in the present embodiment, the predetermined time T
Every minute, the sensor output Vs when the burner 5 is not in the combustion state
Is set as a new zero point reference value V ₀ , and such a value V ₀
As described above, the sensor output Vs corresponding to the carbon monoxide concentration when the burner 5 is in the combustion state is monitored as described above, so that the sensor output Vs is not affected by the above-described vibration, aging, and the like. The concentration of carbon monoxide can be monitored with high accuracy. Moreover, after a predetermined time from the extinguishing of the burner 5
The first new zero point reference value V ₀ is automatically set and
After that, the burner 5 keeps the fire extinguishing state without being ignited.
As long as 0 point reference value V ₀ new every predetermined time automatically set
, So there is no need to ask the user for special operations
There is an advantage.

Also, in the case shown in FIG.
Is turned on, the CP of the water heater control circuit 12 is turned on.
U is activated to supply power to the CO sensor drive circuit 11 (step S1), and thereafter a series of processes from step S6 to step S10 and step S12 in FIG. (Step S2).

[0027] In the case of this reference example, when the burner 5 is extinguished, and so post fan operation for cooling or the like of the water heater body 3 is performed, the timer is started for the post fan ( (Step S3) After the fire extinguishing of the burner 5 is confirmed again (Step S4), when the timer counts a predetermined time, the post-fan time elapses, and when it is determined that the sensor output Vs is stabilized (Step S5), the ( burner 5 is in extinguishing state) reads the sensor output Vs (step S6), and by storing it in the memory 12a in the water heater control circuit 12, zero-point reference value V ₀ which is to generate an alarm is set (Step S7) Then, the fan 4 is stopped (Step S7).
8). If it is determined that the burner 5 is ignited after the start of the timer (step S3) (step S4),
It is determined whether or not the water has been stopped again in the ignition and fire extinguishing process (step S2), and the subsequent fire extinguishing process is performed.

[0028] Thus, also in the present embodiment, during the post-fan operation after burner 5 extinguishing, new zero point reference value V ₀ is set, so that the sensor relative to the such values V ₀ output Vs is monitored Therefore, the concentration of carbon monoxide can be monitored with high accuracy without being affected by the above-mentioned vibration, aging, and the like. Moreover, it is predetermined from the fire extinguishing of the burner 5.
After a time, a new zero point reference value V ₀ is automatically set
And does not require the user to perform any special operations.
There is.

[0029] In the case of this reference example, the first In use after water heater installation, but the setting operation of the zero point reference value V ₀ described above is not performed, in advance predetermined zero point reference value in the factory shipment There is no problem because is set. By the way,
Each of the reference examples shown in FIGS. 6 and 7 shows the post-fire after the burner 5 was extinguished.
Tofan pre-operation and set the zero-point reference value V ₀ new during the
In these, the fan 4
Carbon monoxide that cannot be exhausted by exhaust
If it remains, it is affected by the remaining carbon monoxide,
The sensor output Vs in the absence of carbon monoxide at all
Means that a different value is set as the zero point reference value V _0.
You.

Therefore, the present invention has further solved this problem.
This is a device, and its biggest feature is apparent from the following explanation.
As if, after the burner 5 was extinguished, and the post fan worked
Is completed, the zero point reference value V ₀ of the CO sensor 1 is newly set.
Is to be done.

FIG . 8 shows one example of the flammable gas detection device according to the present invention.
In this embodiment, when the power of the water heater main body 3 is turned on, the CPU of the water heater control circuit 12 is turned on.
Is activated to supply power to the CO sensor drive circuit 11 (step S1), and thereafter, a series of processes from step S6 to step S10 and step S12 in FIG. (Step S2). Thereafter, a timer for the post fan starts (step S3), and when the timer counts a predetermined time and determines that the post fan time has elapsed (step S4), the fan 4 stops (step S5). ).

After that, the timer is started again (step S6), and after extinguishing the fire of the burner 5 again (step S7), if the timer measures a predetermined time and it is determined that the sensor output Vs is stabilized (step S8). Then, the sensor output Vs at that time (the burner 5 is in the fire extinguishing state) is read (step S9), and this is stored in the memory 1 in the water heater control circuit 12.
By storing the 2a, 0 point reference value V ₀ which is for generating an alarm is adapted to be set (step S
10). After the start of the timer (step S6),
If it is determined that the burner 5 is ignited (step S
7) It is determined whether or not the water is stopped again in the ignition and fire extinguishing process (step S2), and the subsequent fire extinguishing process is performed.

Therefore, in the present embodiment, a new zero point reference value V
_{Since 0} is set and the sensor output Vs is monitored based on the value V ₀ , the concentration of carbon monoxide is monitored with high accuracy without being affected by the above-mentioned vibration, aging, and the like. be able to. Moreover, the burner 5 extinguished the fire
When the post fan operation after
Since the value V ₀ is automatically set, special operation to user
Need not be calculated, and the newly set zero point base
The reference value V ₀ is affected by the residual carbon monoxide in the water heater main body 3.
There is an advantage that it does not need to be done.

In the above embodiment, the CO sensor 1
Is composed of a contact combustion type detection element 2, a comparison element for temperature compensation, a bridge circuit composed of a fixed resistor and a movable resistor as in the prior art, but the movable resistance is replaced with a fixed resistor, and the contact combustion type detection element 2, It may be constituted by a bridge circuit composed of a temperature compensating comparison element and two fixed resistors. In this case, it is possible to prevent the movable resistor from being shifted from the adjustment position at the factory due to vibration or the like during use of the water heater. And can be more preferable.

[0035] In the above embodiment, the difference Vs-V ₀ between the sensor output Vs and the new zero point reference value V _0, compared with the alarm level Vr corresponding to dangerous concentrations of carbon monoxide to a predetermined However, without taking the difference Vs−V ₀ , the set value Vr as the absolute alarm level predetermined at the factory stage or the like is set according to the setting of the new zero point reference value V _0.
The same operation and effect can be obtained even if is made variable.

Further, in the above embodiment, the concentration of carbon monoxide in the exhaust gas is detected, but any combustible gas can be detected.

[0037]

[Effect of the Invention] As described above, the flammable gas according to the present invention is used.
The detection device isExhaust exhaust after burner extinguishes
After the end of the post fan operation forBurner burning
Sensor output when not in stateAs the output of the sensing element
Is stored as a zero point reference value for generating an alarm.
Memory and this memorizedOf the sensing elementBased on output,
Output of the detection element after the burner after the fire is ignited
ToSensor output during combustionAsMonitor this
Of the sensing elementOutput is predetermined for a given concentration of combustible gas
Judgment to perform the specified alarm action when the output exceeds the specified output
Means for generating an alarm
Quasi-valueHowever, as the ignited burner extinguishes,
After the fire extinguishes, the post-fan
After the operation is completed, the detection element when the burner is not
Will be updated to the child's output,This allowsAlarm
Any special reference to the zero point reference value of the output of the sensing element to generate
Flammable without fire operation and after burner extinguishing
Can be set appropriately without being affected by gas,Gas fuel
Due to vibration during use of the baking device or aging of the sensing element
Highly accurate combustible gas concentration by preventing deterioration of sensor output performance
Can be monitored at the same time, greatly improving safety and reliability.
And the like.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a combustible gas detection device according to the present invention.

FIG. 2 is a schematic configuration diagram of a gas combustion device having a combustible gas detection device according to a comparative example of the present invention.

FIG. 3 is a block diagram showing a combustible gas detection device provided in the gas combustion device of FIG . 2 ;

It is a flowchart illustrating the operation of the combustible gas detector of FIG. 4 FIG.

FIG. 5 is a flowchart illustrating a warning process in FIG. 4;

FIG. 6 is a flowchart illustrating the operation of the reference example of the combustible gas detection device according to the present invention.

FIG. 7 shows another reference of the combustible gas detection device according to the present invention .
It is a flowchart explaining operation | movement of an example .

FIG. 8 is a flowchart illustrating an operation of the embodiment of the combustible gas detection device according to the present invention .

FIG. 9 is a schematic configuration diagram of a CO sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CO sensor 2 Detecting element 3 Water heater main body 4 Fan 5 Burner 12 Water heater control circuit (CPU)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiaki Tabei 2-25-24 Motomachi, Urawa-shi, Saitama (56) References JP-A-62-266320 (JP, A) (58) Field surveyed (Int. . ^6, DB name) F23N 5/00 F23N 5/24

Claims (1)

(57) [Scope of request for utility model registration] 1. A combustible gas detection device in which a combustible gas contained in exhaust gas discharged from a gas combustion device having a burner is detected by a contact combustion type detection element, wherein the exhaust gas after the burner is extinguished. Storage means for storing the output of the sensing element as a sensor output when the burner is not in a combustion state after the end of the post-fan operation for discharging the gas as a zero-point reference value for generating an alarm; and Based on the stored output of the sensing element, the output of the sensing element after the fire has been ignited is monitored as a sensor output when in a combustion state, and the output of the sensing element is a predetermined concentration of combustible gas. A determination means for performing a predetermined alarm operation when the output becomes equal to or more than a predetermined output.