JPH06229539A - Burner - Google Patents

Abstract

PURPOSE:To detect both CO contamination in a room and an incomplete combustion of a burner by one CO sensor. CONSTITUTION:A communicating hole 11 is provided at an exhaust hood 9, and part of burned exhaust gas is mixed with a combustion air supply passage 8. A CO concentration of the combustion air mixed with the part of the burned exhaust gas is detected to exactly detect both CO contamination in a room and incomplete combustion of a burner 5 by one CO sensor 20 even if the room is contaminated with CO and the incomplete combustion occurs in the burner 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device equipped with a CO sensor for detecting carbon monoxide concentration.

[0002]

2. Description of the Related Art Conventionally, in a combustion device such as a water heater, a safety device for stopping combustion or issuing an alarm when a CO concentration is high is used by using a CO sensor in order to prevent carbon monoxide poisoning. Those equipped are known. For example,
As shown in FIG. 6, a mixture of combustion air supplied to the combustion chamber 2 by the fan 3 and fuel gas supplied from the gas nozzle 4 is burned by the burner 5 to heat the heat exchanger 6, and the combustion is performed. Although there is a water heater that discharges exhaust gas through the exhaust duct 10, in such a combustion device, a CO sensor 20 is provided in the air supply passage 8 (combustion air flow passage) to detect the CO concentration in the room. As shown by the broken line, a safety device is provided such that a CO sensor 30 is provided in the exhaust hood 9 to prevent incomplete combustion of the burner 5 based on the CO concentration in the exhaust.

[0003]

However, in order to detect both CO pollution in the room and incomplete combustion of the burner, it is necessary to provide a CO sensor in each of the air supply passage and the exhaust passage, and the number of parts is increased. And increase in cost, which is not preferable. Further, in order to provide a CO sensor in the exhaust passage, it is necessary to use an expensive CO sensor such as a contact combustion type sensor, which cannot be detected well by a general semiconductor CO sensor. That is, since the commonly used semiconductor type CO sensor utilizes the change in resistance value according to the chemical reaction state of O2 and CO, if it is installed in a place with a low O2 concentration such as an exhaust passage. Even if the actual CO concentration is low, a high value is detected and cannot be used. The combustion apparatus of the present invention solves the above-mentioned problems and solves indoor CO with one CO sensor.
The aim is to detect both pollution and incomplete burner combustion.

[0004]

In order to solve the above-mentioned problems, a first combustion device of the present invention is a combustion device in which a fuel gas and combustion air are mixed and burned by a burner. And a CO sensor for detecting the carbon monoxide concentration of the combustion air mixed with a part of the combustion exhaust gas. Is the gist.

A second combustion apparatus of the present invention is a combustion apparatus in which fuel gas and combustion air are mixed and burned by a burner, and a part of the combustion air is guided to a discharge path of combustion exhaust gas. The gist of the present invention is to have a mixing means for mixing with the combustion exhaust gas and a CO sensor for detecting the carbon monoxide concentration of the combustion exhaust gas in which a part of the combustion air is mixed.

[0006]

In the combustion apparatus of the present invention having the above-mentioned configuration, the mixture of combustion air and combustion exhaust is the object of CO concentration detection. Therefore, both CO pollution in the room and incomplete combustion of the burner are treated as one. It can be detected by a CO sensor.

[0007]

EXAMPLES In order to further clarify the constitution and operation of the present invention described above, preferred examples of the combustion apparatus of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a forced exhaust type (FE type) water heater as one embodiment. In the water heater, a combustion chamber 2 is provided in a main body case 1, combustion air is supplied from a lower portion of the combustion chamber 2 by a fan 3 (sirocco fan), and fuel gas from a gas nozzle 4 and combustion air are burned by a burner 5. It mixes and burns, heats the heat exchanger 6 by the combustion heat, and makes the water in water into hot water.

A gallery 7 is formed on the side surface of the main body case 1, and an air supply passage 8 is provided so that the combustion air is sucked from the room by the negative pressure generated by the rotation of the fan 3 and sent to the combustion chamber 2. . On the other hand, as an exhaust system, an exhaust hood 9 that collects the combustion exhaust in the upper part of the combustion chamber 2 and an exhaust duct 10 that guides the combustion exhaust from the exhaust hood 9 to the outside are provided.

The exhaust hood 9 has a small communication hole 11 formed in its side portion and communicates with the air supply passage 8. Therefore, during combustion, a part of the combustion exhaust gas flows into the air supply passage 8 through the communication hole 11, is diluted by the combustion air from the gallery 7, and is sent to the combustion chamber 2.

A semiconductor type CO sensor 20 is provided in the air supply passage 8 downstream of the communication hole 11 so as to detect the CO concentration of the combustion air mixed with a part of the combustion exhaust gas. It is configured. The CO sensor 20 is connected to a burner controller (not shown) not shown and outputs a signal according to the CO concentration. The burner controller is the CO
A signal from the sensor 20 performs a safety operation such as issuing an alarm or closing the gas passage when the CO concentration is high.

In the water heater of the present embodiment constructed as described above, the combustion air taken in from the room is mixed with a part of the combustion exhaust gas, and the CO concentration of the air-fuel mixture is detected. Even if the burner 5 is incompletely burned, the
Both can be reliably detected by the O sensor 20. Further, in the case of the conventional type, when detecting incomplete combustion, since a CO sensor is provided in the exhaust gas, it is necessary to use an expensive sensor such as a contact type CO sensor so that it can be accurately detected even in a low oxygen concentration environment. However, in this embodiment, since a part of the combustion exhaust gas is mixed with the combustion air, a sufficient oxygen concentration environment is created, and high-precision detection is possible even with an inexpensive semiconductor CO sensor. In addition, it has a simple structure and is almost the same as the conventional one that detects only indoor CO pollution.

Next, another embodiment will be described. Figure 2
Represents a water heater as a modified example of the previous embodiment, and the same parts as those in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted. An exhaust introduction pipe 12 reaching the suction port of the fan 3 is provided on a side portion of the exhaust hood 9. That is, a part of the combustion exhaust gas is configured to be mixed with the combustion air and returned to the combustion chamber 2 through the exhaust gas introduction pipe 12.
In the combustion chamber 2, a semiconductor type CO is provided upstream of the burner 5.
A sensor 20 is provided. Therefore, the CO concentration of the combustion air in which the combustion exhaust gas is diluted is detected, and as in the previous embodiment, both CO pollution in the room and incomplete combustion of the burner can be reliably detected. . Further, a semiconductor CO sensor can obtain sufficient accuracy without using an expensive sensor such as a contact CO sensor to detect incomplete combustion.

As shown in FIG. 3, an air supply duct 13 that connects the gallery 7 and the suction port of the fan 3 is provided to mix a part of the combustion exhaust gas with the combustion air.
The connection pipe 14 may be connected from the side of the exhaust hood 9. Then, the CO sensor 20 is provided in the air supply duct 13 to detect both indoor CO pollution and incomplete combustion. The CO sensor 20 may be provided in the combustion chamber 2 upstream of the burner 5.

When a part of the combustion exhaust gas is returned to the combustion chamber 2 to adversely affect the combustibility, a separator 15 is provided in the air supply duct 13 as shown in FIG. The flow path for mixing a part may be narrowed to reduce the return amount of the combustion exhaust gas.

Next, an embodiment of the combustion apparatus of the second invention will be described. FIG. 5 shows a water heater according to this embodiment, and is provided with a connecting pipe 16 that connects the lower portion of the combustion chamber 2 and the exhaust hood 9 outside the combustion chamber 2. A semiconductor type CO sensor 20 is provided in the exhaust hood 9 near the connecting portion of the connecting pipe 16. That is, the combustion exhaust gas that has passed through the heat exchanger 6 is mixed with the combustion air, and the CO concentration of this mixture is detected. Therefore, as in the previous embodiment, one semiconductor CO sensor 20 can reliably detect both CO pollution in the room and incomplete combustion of the burner 5. Moreover, since the combustion exhaust gas is not returned to the burner 5,
It has no effect on flammability. Further, in the conventional case, an expensive sensor such as a contact type CO sensor has to be provided in the exhaust passage having a low oxygen concentration, but in the present embodiment, the combustion exhaust gas is diluted with the combustion air, so that it is inexpensive. The CO concentration in the exhaust gas can be detected with high accuracy by a simple semiconductor CO sensor.

The embodiment of the present invention has been described above.
The present invention is not limited to these examples, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[0017]

As described in detail above, according to the combustion apparatus of the present invention, it is possible to detect both the CO pollution in the room and the incomplete combustion of the burner with one CO sensor. Play.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 2 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 3 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 4 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 5 is a schematic configuration diagram of a water heater as one embodiment.

FIG. 6 is a schematic configuration diagram of a conventional water heater.

[Explanation of symbols]

2 ... Combustion chamber, 3 ... Fan, 5 ... Burner, 8 ... Air supply passage, 9 ... Exhaust hood, 11 ... Connection hole, 12 ... Exhaust introduction pipe, 13 ... Air supply duct, 14 ... Connection pipe, 20
... CO sensor.

Claims (2)

[Claims] 1. A combustor in which fuel gas and combustion air are mixed and burned by a burner, and a mixing means for guiding a part of combustion exhaust gas to a combustion air supply passage to mix with combustion air. And a CO sensor for detecting a carbon monoxide concentration of combustion air mixed with a part of the combustion exhaust gas. 2. A combustor in which fuel gas and combustion air are mixed and burned in a burner, and a mixing means for guiding a part of the combustion air to a combustion exhaust gas discharge passage and mixing with the combustion exhaust gas. A combustion apparatus, comprising: a CO sensor that detects a carbon monoxide concentration of combustion exhaust gas in which a part of combustion air is mixed.