JPH09178174A - Incomplete combustion preventive device of gas burner apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely stop the supply of gas by appropriately sensing the density of CO gas in the exhaust gas of a burner apparatus by installing a CO gas sensor on the route of the exhaust gas where the coefficient of variation of the generation of the CO gas is large. SOLUTION: A burner 30 comprises one combustion part where the coefficient of variation of the generation of CO gas caused by the decrease in combustion air supply and the decrease in oxygen density is less and the other combustion part where the burning quantity is less compared with the former part but the coefficient of variation of the generation of the CO gas is larger. A CO gas sensor 9 is installed on the route of the exhaust gas from the burning part where the coefficient of variation of the generation of CO gas is larger and detects the CO gas density of the exhaust gas. When the detected CO gas density exceeds a standard density, a controller 12 cuts off the supply of fuel gas to the burner 30. The burner 30 comprises multiple-burner units 3 operating in parallel and the coefficient of variation of generating the CO gas is set larger with a part of the burner units 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to carbon monoxide (C
O) The present invention relates to an incomplete combustion prevention device that stops combustion of a gas combustion device based on detection.

[0002]

2. Description of the Related Art Conventionally, in order to prevent incomplete combustion of gas combustion equipment that causes carbon monoxide poisoning, a CO sensor is provided in an exhaust gas pipe downstream of a burner, and an alarm is issued according to the output of the CO sensor. A safety device for stopping gas combustion is known. For example, a safety device for a gas combustor proposed in Japanese Patent Application Laid-Open No. 5-26440 detects a CO concentration in flue gas by a CO sensor, issues an alarm when this concentration exceeds a first reference concentration, and further emits an exhaust gas. When the CO concentration increases due to recirculation or the like and exceeds the second reference concentration, the gas supply flow path to the burner is closed to stop the fuel gas supply.

[0003]

However, in a combustion device, the CO sensor must be arranged at a high temperature such as a flue gas flow path. CO concentration cannot be detected accurately. Therefore, originally 300
Even if a CO sensor capable of accurately detecting a CO concentration of about ppm is used, the detected value varies at high temperatures in the combustion equipment, and it is difficult to set a reference concentration for CO determination. In other words, there is a problem that even if CO is actually generated below the reference value, the fuel gas supply is stopped because the fuel gas is erroneously determined to be higher than the reference value, or conversely, even if CO is generated above the reference value, it is erroneously determined to be lower than the reference value. Was. Further, it is not safe to raise the determination reference value to a level (for example, 1000 ppm) at which the CO concentration can be accurately detected at a high temperature.

An object of the present invention is to solve the above-mentioned problems and to properly detect the CO concentration in the exhaust gas of a combustion device to stop the fuel gas supply safely. .

[0005]

The incomplete combustion preventing device for a gas combustion apparatus according to claim 1 of the present invention, which solves the above-mentioned problems, has a carbon content due to a decrease in the supply amount of combustion air and a decrease in oxygen concentration.
Burner composed of a combustion part having a small change rate of O generation amount, a combustion part having a smaller combustion amount than the combustion part and a large change rate of CO generation amount, and exhaust gas from the combustion part having a large change rate of CO generation amount A CO sensor provided on the path for detecting the CO concentration in the exhaust gas, and a gas supply stopping means for stopping the fuel gas supply to the burner when the detected concentration of the CO sensor exceeds a reference concentration. The point is to have prepared.

According to a second aspect of the present invention which solves the above-mentioned problems, an incomplete combustion preventing device for a gas combustion device is configured such that the burner is formed by arranging a plurality of burner units in parallel.
The gist is that the change rate of the CO generation amount is set to be large for some of the burner units.

In the incomplete combustion prevention device for a gas combustion device according to claim 3 of the present invention which solves the above-mentioned problems, the rate of change in the amount of CO generated is changed by changing the distribution of the supply of combustion air to the burner. The main point is to provide.

According to a fourth aspect of the present invention which solves the above problems, an incomplete combustion preventing device for a gas combustion apparatus is an exhaust gas for guiding exhaust gas from a combustion portion where the rate of change of the CO generation amount is large to the CO sensor. The main point is to establish a passage.

In the incomplete combustion prevention device for a gas combustion device according to claim 1 of the present invention having the above-mentioned structure, CO is easily generated when the supply amount of combustion air and the oxygen concentration are lowered, but the CO generation amount is reduced. The exhaust gas generated from the combustion part having a large change rate has a higher CO concentration than the exhaust gas generated from the combustion part having a small change rate of the CO generation amount. Since the former has a small amount of combustion, the CO concentration of the entire device, which is actually a problem, is close to the latter's CO concentration, but the CO sensor uses the exhaust gas route from the combustion part where the rate of change of CO generation is large. Since it is provided above, C as the entire actual device
A value higher than the O concentration is detected. Therefore, the determination reference concentration of the CO sensor for determining incomplete combustion can be set to a value higher than the actual CO concentration of the exhaust gas discharged from the device.

According to a second aspect of the present invention, which has the above-mentioned structure, the incomplete combustion preventing device for a gas combustion apparatus includes a burner unit having a small change rate of CO generation amount and a burner unit having a large change rate of CO generation amount. By arranging and in parallel, C
It is possible to easily form the burning portion where O is easily generated and the burning portion where CO is less likely to be generated.

In the incomplete combustion prevention device for a gas combustion apparatus according to claim 3 of the present invention having the above-mentioned structure, the burner unit is made common and the distribution of the combustion air supply amount is changed to change the rate of change of the CO generation amount. Can be formed, and a combustion part with a small rate of change in CO generation can be formed,
Moreover, it can be constructed at low cost.

In the incomplete combustion prevention device for a gas combustion device according to claim 4 of the present invention having the above structure, exhaust gas from a combustion part having a large rate of change in CO generation amount is exhausted from another combustion part by a separator. The CO sensor detects more CO concentration in the exhaust gas from the combustion portion where the rate of change of CO generation is large. Therefore, since the CO sensor detects a value higher than the CO concentration of the entire device, it is possible to set the determination reference concentration of the CO sensor to a higher value.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In order to further clarify the constitution and operation of the present invention described above, a preferred embodiment of the incomplete combustion preventing device for a gas combustion apparatus of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a water heater equipped with an incomplete combustion prevention device as one embodiment of the present invention. This gas water heater is a forced air supply type water heater, and includes a case 1 that forms a combustion chamber, a gas burner 30 that burns gas supplied from a gas supply passage 2, and a water supply pipe 4 that is burned by the gas burner 30.
The heat exchanger 6 that heats the water that has flowed from the hot water and sends it to the hot water discharge pipe 5, the exhaust pipe 8 that serves as a passage that sends the exhaust gas generated by combustion to the outside through the exhaust hood 7, the heat exchanger 6, and the exhaust gas. CO for detecting the CO concentration of exhaust gas with the hood 7
It comprises a sensor 9, a fan 10 provided at the bottom of the case 1 for supplying combustion air into the case 1, a rectifying plate 11 for rectifying the combustion air, and a controller 12 for controlling combustion.

The gas burner 30 is composed of a plurality of identical burner units 3, and some of the burner units 3 (the burner unit 3a at the rightmost end in this embodiment) are part of the straightening plate 1.
1 or a damper (an opening for adjusting the air intake amount around the gas injection nozzle) to reduce the supply of primary air and secondary air, and the rate of change of the CO generation amount with respect to the decrease in the oxygen supply amount. To form a large burned portion (hereinafter referred to as sensing burner 3a). Therefore, if the supply air amount and the oxygen concentration are normal, complete combustion occurs, but if they decrease, the CO generation rate from the sensing burner 3a rapidly increases. However, the ratio of the combustion amount of the sensing burner 3a to the whole is low, and the main combustion is due to another burner unit (hereinafter referred to as the main burner 3), so the CO concentration as a whole is only that of the main burner 3. Almost same as CO concentration.

A main solenoid valve 13, a proportional solenoid valve 14, and a main solenoid valve 15 are provided in series in the gas supply passage 2. The original solenoid valve 13 and the main solenoid valve 15 are valves that only open and close the gas flow path, and the proportional solenoid valve 14 is a control valve that is set to an opening degree according to a control signal and adjusts to a desired gas supply amount. is there.

The CO sensor 9 is provided directly above the sensing burner 3a, and a separator 16 is provided so that the exhaust gas generated from the main burner 3 does not enter the CO sensor 9 side. Therefore, the CO sensor 9 detects only the CO concentration of the exhaust gas generated from the sensing burner 3a.

The controller 12 includes a CPU, a RAM, and a ROM which constitute a well-known arithmetic and logic operation circuit (not shown),
It comprises an input interface for inputting signals from various sensors, an output interface for outputting drive signals to various actuators, and the like. Then, based on the signal from the CO sensor 9, not only the solenoid valves 13, 14, 15 are opened and closed, but also the hot water temperature control, the ignition control, etc. are performed together, but it is directly related to the present invention. Not a sensor,
The description and illustration of the ignition device and the like are omitted.

FIG. 2 is a flowchart showing an incomplete combustion prevention control routine executed by the controller 12.
It starts in accordance with the ignition operation. When this routine is started, an ignition device (not shown) ignites the gas burner 30 to start combustion (S1). When the gas burner 30 burns, the CO sensor 9 detects the CO concentration of the exhaust gas generated by the burning of the sensing burner 3a (S2).

When the supply air amount and the oxygen concentration are normal, the CO concentration of the exhaust gas of both the main burner 3 and the sensing burner 3a is low, so the CO sensor 9 detects less than the set value (S).
3: NO). As the combustion state deteriorates due to lack of air supply or lack of oxygen, the CO concentration of the exhaust gas increases in both the main burner 3 and the sensing burner 3a.

Here, as shown in FIG. 3, the transition a of the CO concentration in the sensing burner 3a becomes sharply higher than the transition b of the main burner 3, but since the proportion of the burner as a whole is low, the total of both burners is low. The CO concentration at 2 is close to the transition b of the CO concentration of the exhaust gas of the main burner 3. However, since the CO sensor 9 detects the CO concentration of the exhaust gas of the sensing burner 3a, the CO concentration is considerably higher than the total CO concentration, that is, the CO concentration that is actually a problem. Therefore, C
If you want to keep the O concentration below 300 ppm, for example, CO
The setting value of the sensor 9 is higher than that, for example, 2
Set to 000 ppm. Here, considering a case where the detection error range of the CO sensor 9 is, for example, 2000 ± 500 ppm, the CO sensor 9 determines the set value in the range from A1 to A2. However, since the transition b is more gradual than the transition a, the error range of the CO concentration of the transition b due to the error range of the CO sensor 9 is narrowed from B1 to B2, and the total CO concentration error range is also reduced. Narrows. Therefore, even if the CO sensor 9 that cannot accurately detect a low CO concentration is used, by setting the set value of the CO sensor 9 to a high level while suppressing the total CO concentration of the burner 30 to be low, CO in total
The concentration can be accurately captured.

When the CO concentration exceeds the set value, the CO
When the sensor 9 detects (S4: YES), the original solenoid valve 1
3. The proportional solenoid valve 14 is closed to stop the gas supply to the burner 3, and an annunciator (not shown) displays an error (S
5).

As described above, according to the water heater provided with the incomplete combustion prevention device of this embodiment, even if a CO sensor that cannot accurately detect when the CO concentration is low is used, the exhaust gas of the burner with a high CO generation rate is obtained. The CO concentration of the exhaust gas can be accurately detected by detecting the CO concentration of. Therefore, an extremely safe incomplete combustion preventing device can be realized. Also,
Since the burner unit is also used, the cost is low and the manufacturing is easy.

In the present embodiment, the combustion portion having different rates of change of the CO generation amount is formed by changing the distribution of the combustion air supply. For example, the Bunsen type burner and the all primary type burner are used. Different burners may be used, and the burner area of the same burner may be changed. Further, the rate of change of the CO generation amount with respect to the decrease of the supply air amount or the oxygen concentration may be increased for a part of the single burner, without configuring the burner unit with a plurality of burner units. Further, in the present embodiment, the exhaust passage is provided for the CO sensor to detect only the CO concentration of the exhaust gas of the sensing burner. However, the exhaust passage is not provided and the CO sensor is simply provided on the exhaust passage side of the burner where CO is likely to occur. May be installed in
Further, the separator may be further extended to the burner side in order to prevent the exhaust gas from being mixed. Further, when the CO concentration becomes equal to or higher than a set value, control means may be adopted such that the fan speed is increased to improve the combustibility before the gas supply is stopped.

The embodiments of the present invention have been described above.
The present invention is not limited to these embodiments, and it is needless to say that the present invention is not limited to, for example, a water heater and can be implemented in various modes without departing from the scope of the present invention.

[0025]

As described in detail above, claim 1 of the present invention
According to the incomplete combustion prevention device for the gas combustion equipment described above, C
Since the O sensor detects the CO concentration of the exhaust gas from the combustion portion where the rate of change in CO generation is large, the reference concentration of the CO sensor can be set to a value higher than the actual CO concentration. For this reason, CO with large detection error at low CO concentration
Even if a sensor is used, the CO concentration can be accurately detected, incomplete combustion can be reliably prevented, and safety is high.

Further, according to the incomplete combustion prevention device for a gas combustion device according to the second aspect of the present invention, a burner unit having a small rate of change in CO generation and a burner unit having a large rate of change in CO generation. By arranging and in parallel with each other, it is possible to easily form a combustion portion where CO is easily generated and a combustion portion where CO is less likely to be generated, which facilitates manufacturing.

Further, according to the incomplete combustion prevention device for a gas combustion device according to claim 3 of the present invention, the rate of change of the CO generation amount is large by making the burner unit common and changing the distribution of the air supply amount. Since the burning portion and the burning portion with a small rate of change in CO generation amount are formed, the cost is low and the manufacturing is easy.

Further, according to the incomplete combustion prevention device for a gas combustion device according to claim 4 of the present invention, the exhaust gas from the combustion part where the rate of change of the CO generation rate is large is exhausted from the other combustion part by the separator. Since the flow rate is divided into the following and flows to the CO sensor, the reference concentration of the CO sensor can be set to a higher value, and the detection accuracy becomes more accurate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a water heater provided with an incomplete combustion prevention device as one embodiment.

FIG. 2 is a flowchart showing an incomplete combustion prevention control routine executed by a controller.

FIG. 3 is a graph showing the CO concentration of exhaust gas generated from each burner.

[Explanation of symbols]

1 ... Case, 2 ... Gas supply path, 9 ... CO sensor,
10 ... Fan, 11 ... Rectifier plate, 12 ... Controller,
30 ... Gas burner.

Claims (4)

[Claims] 1. A combustion part in which the rate of change in CO generation due to a decrease in the supply of combustion air or a decrease in oxygen concentration is small, and a combustion part in which the amount of combustion is smaller than the combustion part and the rate of change in CO generation is large. And a CO sensor for detecting the CO concentration in the exhaust gas, which is provided on the path of the exhaust gas from the combustion part where the rate of change of the CO generation is large, and the detected concentration of the CO sensor exceeds the reference concentration. In this case, an incomplete combustion prevention device for gas combustion equipment, comprising: a gas supply stopping means for stopping the supply of fuel gas to the burner. 2. The burner is configured by arranging a plurality of burner units in parallel, and the change rate of the CO generation amount is large with respect to some of the burner units. The incomplete combustion prevention device for a gas combustion device according to 1. 3. The burner is configured by arranging a plurality of identical burner units in parallel, and by reducing the supply distribution of the combustion air to some of the burner units, the rate of change in the CO generation amount is small or large. The incomplete combustion prevention device for a gas combustion device according to claim 2, further comprising: 4. A separator is provided for guiding the exhaust gas from a combustion part where the rate of change of CO generation is large from the exhaust gas from another combustion part to the CO sensor. Item 1. An incomplete combustion prevention device for a gas combustion device according to item 1, 2 or 3.