JPH1038265A - Combustion condition judging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion condition judging device capable of correctly understanding whether or not the combustion condition is abnormal according to causes for occurrences of abnormal combustion, and capable of performing appropriate treatment according to the cause of occurrence. SOLUTION: An operation part 27 starts the combustion at the combustion number according to the required number to be determined by the set value of the hot water temperature, the inlet water temperature, the feed water flow rate, etc. When the combustion is transferred from the initial condition to the stationary condition and the FR current value is in the stable condition, the FR current value is read through a resistance 23, the read FR current value is compared with the second threshold 50μA to check whether or not the FR current value is larger than 50μA. If it is smaller than 50μA, it is judged to be abnormal combustion caused by oxygen deficiency, the combustion is immediately and forcibly stopped, each part of the combustion device is locked out, and an error display is made that combustion is forcibly stopped because abnormal combustion is generated due to oxygen deficiency. If the FR current value is larger than 20μA. abnormal combustion caused by shortage of air volume, and the combustion is continued while controlling the increase of the air feed to burners 7-15 or reduction of the combustion number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a combustion state judging device for judging whether a combustion state in a combustion device is normal or abnormal.

[0002]

2. Description of the Related Art Conventionally, in a combustion device provided in a water heater or the like for burning fluid fuel such as gas, a combustion state is monitored based on an output signal from a sensor such as a frame rod (FR) or a thermistor. There is known a combustion state determination device that determines normal combustion / abnormal combustion. If the determination device includes, for example, an FR for detecting a flame current, the combustion state is determined based on a comparison result between the detected FR current value and a threshold value of the FR current value for determining normal combustion / abnormal combustion. Normal / abnormal.

[0003]

The abnormal combustion state in the above-mentioned combustion apparatus is, for example, a shortage of air supply to the burner caused by dew condensation occurring in the heat exchanger and the heat exchanger becoming blocked. And a decrease in O2 concentration (oxygen deficiency) in the atmosphere in which the combustion device is installed. Moreover, even in the same abnormal combustion state, the detected value of the FR current differs for each cause of the abnormal combustion. Therefore, it is necessary to provide a threshold for determining whether or not the combustion is abnormal for each cause of the occurrence. In some cases, it may be difficult to accurately determine the abnormal state, or even to determine whether or not the combustion state is abnormal.

[0004] However, in the above combustion state determination device, only one determination is made mainly because only the determination of normal / abnormal of the combustion state is considered, so that only one threshold value is provided. Therefore, if this threshold is set to a value suitable for determining whether or not abnormal combustion is caused by a shortage of air supply, an abnormal combustion state caused by oxygen deficiency cannot be grasped, and It will not be possible to take measures to forcibly stop combustion. Conversely, if the threshold is set to a value suitable for determining whether or not abnormal combustion due to oxygen deficiency, the abnormal combustion state caused by insufficient air supply cannot be grasped. However, there has been a problem that measures such as control of increasing the amount of air supplied to the burner and control of decreasing the number of combustions cannot be taken.

Accordingly, an object of the present invention is to make it possible to accurately determine whether or not an abnormal combustion state has occurred in a combustion apparatus according to the cause of abnormal combustion, and to take appropriate measures in accordance with the cause of occurrence. Another object of the present invention is to provide a simple combustion state determination device.

[0006]

According to a first aspect of the present invention, there is provided a combustion state determining apparatus for determining whether a combustion device is in an abnormal combustion state by detecting a state quantity of the combustion device. And a storage unit and a determination unit. The storage means stores all state quantity thresholds for determining whether the combustion state is normal or abnormal, which are specific to each of a plurality of causes of the abnormal combustion state. The determination means determines whether the combustion state of the combustion device is normal or abnormal by comparing the detected state quantity with each of the state quantity thresholds.

According to the first aspect of the present invention, the normal state / abnormal state of the combustion state of the combustion apparatus is determined by comparing the detected state quantity with all the state quantity thresholds. Unlike the conventional device in which only one quantity threshold was set, the abnormal combustion state caused by any cause can be surely grasped, and appropriate measures can be taken according to the cause. it can.

In a preferred embodiment according to the first aspect of the present invention, the state quantity of the combustion device is determined by detecting a flame current from flame current detection means for detecting a flame current inserted in a flame of a burner of the combustion device. Value. The causes of the abnormal combustion state include a shortage of air supply to the burner of the combustion device and a lack of oxygen in the atmosphere in which the combustion device is installed. A first threshold for determining whether or not an abnormal combustion state is caused by a shortage of the supply amount, and a second threshold for determining whether or not the abnormal combustion state is caused by a lack of oxygen in the atmosphere. I have. The first and second threshold values can be changed according to the installation conditions of the combustion device and the type of burner.

As described above, since the first and second thresholds can be changed according to the installation conditions of the combustion device and the type of the burner, the installation conditions of the combustion device are not limited, and the combustion device is not limited. It is possible to accurately grasp whether or not the apparatus is in an abnormal combustion state even if the apparatus is installed under any installation conditions.

In another preferred embodiment according to the first aspect of the present invention, the second threshold value is smaller than the first threshold value, and the judging means determines that the flame current detection value is equal to the first threshold value. When it is within the area determined by the second threshold, it is determined that the combustion state is normal, and when the flame current detection value is larger than the first threshold value, it is determined that the combustion state is abnormal due to insufficient air supply. When it is smaller than the second threshold value, it is determined that the combustion state is abnormal due to oxygen deficiency. In this case, a configuration may be further provided that includes a control unit that controls each unit of the combustion apparatus in order to take a measure according to the cause of the abnormal combustion based on the determination result by the determination unit. The control unit increases the air supply amount to the burner when the determination unit determines that the combustion state is abnormal due to the insufficient air supply amount, decreases the burner combustion amount, or performs both of the above controls. When the determination means determines that the combustion state is abnormal due to oxygen deficiency, control is performed to forcibly stop the combustion operation of the combustion device.

In another preferred embodiment, the control means increases the air supply amount to the burner when the determination means determines that the combustion state is abnormal due to insufficient air supply amount,
If the determination means does not determine that the abnormal combustion state has been resolved by reducing the burner combustion amount or performing both of the above controls and performing either control, control is performed to forcibly stop the combustion operation of the combustion device. .

With this configuration, it is possible to prevent various accidents from occurring due to the lack of oxygen. Further, if the abnormal combustion state due to the shortage of air can be brought close to the normal combustion state, no problem occurs even if the combustion operation is continued. Therefore, the combustion operation is continued while outputting an error display. Therefore, there is no inconvenience to the user such as the inability to use the combustion device until a service person for maintenance comes.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a combustion device to which a combustion state determination device according to one embodiment of the present invention is applied.

The above-mentioned combustion device constitutes, for example, a combustion system of a water heater, and as shown in FIG.
, An air introduction part 3, a metal body 5, and a plurality of burners 7-1.
5, an insulating member 17, an FR 19, a resistor 23, a transformer 25, an arithmetic processing unit 27, a storage unit 29, and a combustion system control device 31.

The outside air suction fan 1 is provided at an end of the air introduction unit 3 and is driven to supply external air into the air introduction unit 3. The air introduction unit 3 introduces the air supplied from the fan 1 to the burner side as primary air for forming an air-fuel mixture with fuel gas, and separately as secondary air for supplementing oxygen. The metal body 5 is provided on an outer wall surface of the air introduction unit 3.

Each of the burners 7 to 15 has a base end connected to the metal body 5 at a predetermined interval from each other, and each air-fuel inlet (not shown) has an air inlet 3 and a gas manifold (not shown). Are provided so as to communicate with each other.

In the present embodiment, the interval 33 between the burners 7 to 15 is such that the flames 21 do not contact each other and the C
The distance is set such that the degree of contact between the flames 21 increases as the flame width increases with an increase in the O concentration value (transition to an abnormal combustion state). This distance depends on each burner 7
The size of the flame 21 blown out from the nozzles 15 to 15 (the size of the flame is affected by the structure of the burner and the type of gas used as the fuel gas) is different and cannot be uniquely determined. The value is set to the extent that the fire is not deteriorated in the case of .about.15. Furthermore, secondary air introduction holes necessary for introducing secondary air for supplementing oxygen to the burners 7 to 15 at the portions of the air introduction unit 3 and the metal body 5 corresponding to the installation intervals 33, respectively. 41 are formed respectively.

FR19 is an insulating member 1 for detecting a flame.
7 and faces the flame outlets of the burners 7 and 9. The resistor 23 and the transformer 25 are provided so as to form a closed loop for passing an electric current together with the FR 19, the burners 7, 9, and the metal body 5 through the flame 21 blown out from the burners 7, 9.

Here, a current flowing through the above-described closed loop including the FR 19 (hereinafter referred to as an FR current) includes a burner 7.
When the ratio of fuel gas to the mixture of fuel gas and air increases due to a decrease in the amount of air supplied to -15, the combustion speed increases and the value increases. Also,
The FR current also has the property that when the O2 concentration in the atmosphere decreases, the combustion reaction itself decreases even if the amount of air supplied to the burner does not change due to the lack of O2, and the value decreases accordingly. is there. Therefore, in the present embodiment, when the combustion device enters an abnormal combustion state by focusing on the nature of the FR current, an attempt is made to identify the cause.

The storage unit 29 contains a program that defines the processing operation of the arithmetic processing unit 27, and is used by the arithmetic processing unit 27 to determine whether an abnormal combustion state is occurring and to specify the cause of the abnormal combustion state. Various necessary data are stored. These data include, for example, data indicating the relationship between the CO concentration in the exhaust gas exhausted from the combustion device and the FR current value, the O2 concentration in the atmosphere where the combustion device is installed, and the F value.
Data indicating the relationship with the R current value and the like are given.

FIG. 2 shows the storage unit 29 as data necessary for determining whether or not an abnormal combustion state is occurring and for identifying the cause of the abnormal combustion state.
FIG. 4 is a characteristic diagram showing a relationship between the CO concentration in the exhaust gas and the FR current value stored in FIG. FIG. 3 is a characteristic diagram showing the relationship between the O2 concentration in the atmosphere and the FR current value stored in the storage unit 29 as data necessary for the above determination and the identification of the cause. The data shown in FIGS. 2 and 3, respectively, are obtained by sampling a combustion apparatus having a specific type of burner in a state where the combustion apparatus is burned at a combustion number of 16.

In FIG. 2, if the FR current value is 100 μA, the value of 100 μA is the value indicated by the point a on the curve 33 showing the CO concentration-FR current value characteristic. Has a CO concentration of 100 ppm. This FR current value = 100 μA (that is, the CO concentration =
100 ppm) is a reference value when determining that the combustion device is in a normal combustion state. On the other hand, when the FR current value is 200
In the case of μA, this value of 200 μA corresponds to the curve 33
Since the value is indicated by the point b above, the CO concentration in the exhaust gas at that time is 2000 ppm.

This is because the heat exchanger (not shown) constituting the hot water supply system is in a relatively lightly blocked state (hereinafter referred to as a heat exchanger blocked state) due to dew condensation or the like, resulting in an insufficient amount of air. This indicates that the combustion device is in an abnormal combustion state due to the shortage of the air amount. In the present embodiment, CO 2
When the detected FR current value indicates that the concentration value is within the range of 100 ppm to 2000 ppm, it is assumed that the combustion device is in a normal combustion state.

On the other hand, when the CO concentration value is from 2000 ppm to the CO concentration value X (curve 33) indicating a relatively severe blockage of the heat exchanger.
It is assumed that the area is within the region up to (corresponding to point e above) F
When the R current detection value indicates, it is considered that the combustion state is close to a normal combustion state by performing control to increase the amount of air supplied to the burners 7 to 15 and control to reduce the number of combustions. Shall be considered. Further, when the detected value of the FR current indicates that the CO concentration value is within the range of (> X), the abnormal combustion state is obtained even if the control for increasing the air supply amount or decreasing the combustion number is performed. Is assumed to be in an extremely severe heat exchanger blockage condition that cannot be reduced.

In the present embodiment, as will be described later, the FR current value = 200 μA is used as a threshold (first threshold) for determining whether the combustion state is normal or abnormal combustion due to blockage of the heat exchanger. I decided that. This first threshold data is based on the installation conditions of the combustion device (for example, whether the device is installed outdoors or indoors, whether it is a location where air circulation is good in the case of outdoor installation, or whether it is a location in a closed state in the case of indoor installation. Or the like).

Next, in FIG. 3, the FR current value is 100
If it is μA, this value of 100 μA is O2 concentration-F
Since the value is indicated by the point c on the curve 35 showing the R current value characteristic, the O2 concentration in the atmosphere at that time is 21%, which indicates that the combustion apparatus is in a normal combustion state. This FR current value = 100 μA (that is, O2 concentration =
21%) is a reference value when it is determined that the combustion device is in a normal combustion state, as in FIG. On the other hand, if the FR current value is 50 μA, the value of 50 μA is the value indicated by the point d on the curve 35,
The O2 concentration in the atmosphere at that time is 18%.

This indicates that the combustion device is in an abnormal combustion state due to lack of oxygen. This FR current value = 50 μ
The abnormal combustion state indicated by A (O2 concentration value = 18%)
When the combustion device is installed outdoors, it is considered that the combustion device is mainly caused by oxygen deficiency caused by exhaust gas circulation of the combustion device itself. Further, when the combustion device is installed indoors in a closed state, it is considered that the combustion devices are caused by oxygen deficiency due to exhaust gas circulation in the indoors.

Here, when the FR current detection value indicates that the O 2 concentration is within the range of 18% to 21%, for example, the combustion device is installed outdoors or installed indoors with low airtightness. In such a case, it is considered that there is a relatively mild oxygen deficiency in which no problem occurs even if the combustion is continued. Therefore, in the present embodiment, when the detected FR current value indicates that the O2 concentration is within the above range, the combustion device is considered to be in a normal combustion state. On the other hand, when the detected value of the FR current indicates that the O2 concentration is within the range of (<18%), it is assumed that an oxygen-deficient state needs to immediately stop the combustion.

Therefore, in this embodiment, the FR current value = 5
0 μA is used as a threshold (second threshold) for determining whether or not to continue combustion in an abnormal combustion state caused by oxygen deficiency. This second threshold value data can also be freely changed according to the above-described installation conditions of the combustion device.

Returning to FIG. 1, the arithmetic processing section 27 receives the voltage signal generated at the resistor 23 and executes the processing operation described below. That is, when the combustion device is in a steady combustion state and the FR current value is stable, the FR current detection value is read, and the FR current detection value and the first and second threshold data stored in the storage unit 29 are read. Compare with

Based on the result of the comparison, the normal / abnormal combustion state is determined, the cause of the abnormal combustion is determined, and the action (rotation of the fan 1) according to the specified cause of the abnormal combustion is determined. Control of increasing the air supply by increasing the number,
The control for reducing the combustion number and the control for stopping the combustion are executed via the combustion system control device 31. Arithmetic processing unit 27
4 will be described in detail with reference to the flowchart of FIG.

The combustion system controller 31 opens a gas solenoid valve (not shown) for disconnecting / connecting between a gas supply source (not shown) and the gas manifold based on the notification from the arithmetic processing unit 27. / Closer control and each burner 7-1 from gas supply source
The opening degree of a gas proportional valve (not shown) for adjusting the amount of gas supplied to the fan 5 and the rotation speed of the fan 1 are controlled. When notified by the arithmetic processing unit 27 that combustion should be stopped, the combustion system control device 31 closes the gas solenoid valve (not shown) and stops the combustion of the combustion device.

Next, the processing procedure for determining the combustion state in the combustion apparatus having the above configuration will be described with reference to the flowchart of FIG.

The arithmetic processing unit 27 first confirms a combustion command from an operation panel (not shown) (step S1).
Each part of the combustion device is controlled via the combustion system control device 31 to start a combustion operation at a combustion number corresponding to the required number determined based on the hot water supply temperature set value Ts, the incoming water temperature value Tc, the supply water flow value Q, and the like. (Steps S2 and S3). Next, when it is confirmed that the combustion has shifted from the initial state to the steady state and the FR current value has become stable (steps S4 and S4).
5), reading of the FR current value via the resistor 23 is started (step S6).

Next, the read FR current value is compared with 50 μA, which is the second threshold value, to check whether the FR current value is greater than 50 μA (step S7). Here, if the FR current value is smaller than 50 μA, it is determined that the combustion is abnormal due to lack of oxygen (step S8).

In this case, as described above, O
(2) Since the concentration is less than 18%, the combustion is forcibly stopped immediately to put each part of the combustion apparatus into a lockout state (a state in which the combustion apparatus cannot be restarted). Is displayed on a display (not shown) as an error display (step S9). This makes it possible to prevent various accidents from occurring due to the lack of oxygen.

On the other hand, if the FR current value read in step S6 is larger than 50 μA (step S7), since at least abnormal combustion due to lack of oxygen is not caused, step S6 is performed.
8, the processing shown in S9 is not performed, and the FR current value is compared with the first threshold value of 200 μA.
Check whether it is smaller than 00 μA (step S
10). Here, if the FR current value is smaller than 200 μA, it is determined that the combustion is normal, and the combustion operation with the required number is continued as it is (step S11).

As a result of the check in step S10, FR
If the current value is larger than 200 μA, it is determined that the combustion is abnormal due to insufficient air volume (due to blockage of the heat exchanger) (step S12), and control of increasing the amount of air supplied to the burners 7 to 15 or reducing the number of combustions is performed. The combustion operation is continued while performing control to cause the combustion (step S13).

By performing such control, an abnormal combustion state due to an insufficient amount of air can be brought close to a normal combustion state, so that there is no problem even if the combustion operation is continued.
In this case, the combustion operation is continued while outputting an error display on the display. Therefore, there is no inconvenience to the user such as the inability to use the combustion device until a service person for maintenance comes.

The detected FR current value read in step S6 indicates that the blocked state of the heat exchanger is extremely severe (that is, the detected FR current value corresponds to the CO concentration value X in FIG. 2). At this time, the combustion operation may be forcibly stopped without executing the process shown in step S13 for safety.

In the present embodiment, the first threshold for determining whether or not the heat exchanger is blocked is set to 200 μA, and the second threshold for determining whether or not oxygen deficiency is set to 50 μA. These thresholds can be freely changed according to the installation conditions of the combustion device.

That is, as described above, when the combustion device is installed outdoors, even if abnormal combustion occurs due to insufficient air volume, it is extremely rare for the user to suck the exhaust gas from the combustion device. Therefore, the first threshold value may be set to a value larger than 200 μA, or the processing operation of outputting an error display on the display may be omitted. On the other hand, even if abnormal combustion due to lack of oxygen occurs, it is considered that the cause is caused by the exhaust gas circulation of the combustion device itself, and there is no danger to the user. Therefore, the second threshold value is set to a value smaller than 50 μA. Can be set to.

On the other hand, a combustion device installed indoors
In the case of a type in which the exhaust gas is directly discharged indoors, if the heat exchanger is blocked, the first threshold value is set to 200 μA because the exhaust gas having a high CO concentration may be sucked by the user.
It is also necessary to set a value considerably lower than that (for example, 100 μA), and in some cases, control to stop combustion. Further, in the above-described type of combustion device, when oxygen deficiency occurs, the second threshold value needs to be set to a value considerably higher than 50 μA in order to protect the user from an oxygen deficiency accident.

As described above, according to the embodiment of the present invention, it is possible to improve the reliability of determining whether the combustion state is normal / abnormal, and to determine the cause of the abnormal combustion when the abnormal combustion is determined. Therefore, a measure commensurate with the cause can be taken. Therefore, it has become possible to provide a safer combustion device.

The above description relates only to the combustion state judging device according to one embodiment of the present invention, and it does not mean that the present invention is limited to the above content.

[0047]

As described above, according to the present invention,
In a combustion device, it is possible to provide a combustion state determination device capable of accurately grasping whether or not an abnormal combustion state occurs according to a cause of abnormal combustion and performing an appropriate measure in accordance with the cause. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram of a combustion apparatus to which a combustion state determination device according to an embodiment of the present invention is applied.

FIG. 2 is a characteristic diagram showing a relationship between a CO concentration in exhaust gas and an FR current value.

FIG. 3 is a characteristic diagram showing a relationship between an O2 concentration in an atmosphere and an FR current value.

FIG. 4 is a flowchart showing a procedure for determining a combustion state in the configuration of FIG. 1;

[Explanation of symbols]

 Reference Signs List 5 metal body 7, 9, 11, 13, 15 burner 19 flame rod (FR) 21 flame 23 resistance 25 transformer 27 arithmetic processing unit 29 storage unit 31 combustion system control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Munemura 43-1 Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Within Nihon Yupro Co., Ltd. (72) Shigeo Yoshida 43-1 Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo No. Japan Yupro Co., Ltd.

Claims (8)

[Claims] An apparatus for determining whether a combustion apparatus is in an abnormal combustion state by detecting a state quantity of the combustion apparatus, wherein the combustion state determination apparatus determines whether or not the combustion apparatus is in an abnormal combustion state. of,
Storage means for storing all state quantity thresholds for determining whether the combustion state is normal / abnormal; and comparing the detected state quantity with each of the state quantity thresholds to thereby determine whether the combustion state of the combustion device is normal or abnormal. A combustion state determination device, comprising: determination means for determining abnormality. 2. The combustion state judging device according to claim 1, wherein the state quantity of the combustion device is detected by a flame current detection means for detecting a flame current by being inserted into a flame of a burner of the combustion device. A combustion state determination device characterized by a value. 3. The combustion state determination device according to claim 1, wherein the cause of the abnormal combustion state is a shortage of air supply to a burner of the combustion device and an atmosphere in an atmosphere where the combustion device is installed. An oxygen deficiency, wherein the state quantity threshold is a first threshold for determining whether or not an abnormal combustion state is caused by insufficient air supply to the burner, and an abnormality is caused by oxygen deficiency in the atmosphere. A second threshold value for determining whether or not a combustion state is present. 4. The combustion state determination device according to claim 3, wherein the first and second thresholds are set based on an installation condition of the combustion device,
A combustion state determination device, which can be changed according to the type of the burner. 5. The combustion state determination device according to claim 1, wherein the second threshold value is smaller than the first threshold value, and wherein the determination unit includes the flame. When the detected current value is within a region determined by the first threshold value and the second threshold value, it is determined that the combustion state is normal, and when the detected flame current value is larger than the first threshold value, it is caused by insufficient air supply. A combustion state judging device that judges an abnormal combustion state caused by oxygen deficiency when the flame current detection value is smaller than the second threshold value. 6. The combustion state determination device according to claim 1, further comprising control means for controlling each part of the combustion device based on a result of the determination by the determination means so as to take a measure corresponding to a cause of abnormal combustion. A combustion state determination device characterized by the above-mentioned. 7. The combustion state determination device according to claim 1, wherein the control unit determines that the burner is in an abnormal combustion state due to an insufficient air supply amount. The combustion operation of the combustion device is performed when the amount of air supplied to the burner is increased, the amount of combustion of the burner is reduced, or both controls are performed, and the determination unit determines that the combustion state is abnormal due to oxygen deficiency. A combustion state determination device for performing control for forcibly stopping the combustion. 8. The combustion state determining apparatus according to claim 1, wherein the control unit determines that the burner is in an abnormal combustion state due to an insufficient air supply amount. The amount of air supplied to the burner is increased, the amount of combustion of the burner is reduced, or both of the controls are performed. A combustion state determination device for forcibly stopping a combustion operation of the combustion device.