JP2003035401A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve combustion property in extinguishment, and prevent odor of non-combusted mixed gas from occurring. SOLUTION: There are provided a thin combustion section 20 composed of a thin inlet section 21 for sucking a fuel and air, a thin mixing chamber 22, and a thin flame hole 23, a thick combustion section 24 constructed with a thick inlet section 25 for sucking a fuel, a thick mixing chamber 26, and a thick flame hole 27, and a communication hole 29 communicating the thin mixing chamber 22 and the thick mixing chamber 26. Hereby, a fuel flowing into and being accumulated in the thick inlet section 25 has a slow flow speed, so that a thick flame is kept longer than a thin flame. Therefore, since the thick flame keeps the thin flame up to the last, the thin flame is prevented from being blown out, and hence odor is prevented from happening owing to non-combusted diluted premixed gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device for reducing NOx especially in a domestic or commercial combustion device.

[0002]

2. Description of the Related Art Heretofore, as this kind of combustion apparatus, there has been, for example, one described in Japanese Patent Publication No. 9-260447. 6 and 7 show the conventional combustion device described in the above publication.

In FIG. 6 and FIG. 7, the lean burn portion 1 is provided with an elongated lean flame port 2 for ejecting a lean premixed fuel which is leaner in fuel than the stoichiometric air-fuel ratio. The rich combustion section 3 was provided with an elongated rich flame port 4 for ejecting a rich premixed fuel having a fuel richer than the stoichiometric air-fuel ratio. A plurality of blocks of the light combustion section 1 and the rich combustion section 3 are provided, and the gap between the block outer walls forms a secondary air chamber. Then, the secondary air adjacent to the rich flame port 4 is configured to be ejected through the secondary air outlet 6. Further, the lean inlet portion 7 into which the fuel and the primary air flow is exposed to the air chamber 8 communicating with the combustion fan (not shown), and the lean nozzle 9 for ejecting the fuel is opposed to the lean inlet portion 7. . The rich inlet portion 10 into which the fuel and the primary air flow has a smaller opening area than the light inlet portion 7 and faces the air chamber 8, and the rich nozzle 11 from which the fuel is ejected is opposed to the rich inlet portion 10. Further, the ignition means was provided downstream of the rich flame opening 4A, and the flame detection means 13 was provided downstream of the rich flame opening 4B.

Next, the combustion operation will be described. The air blown into the air chamber 8 by the combustion fan has flown from the lean inlet section 7 and the rich inlet section 10 into the lean burn section 1 and the rich burn section 3 as primary air, respectively. At the same time, the fuel ejected from the light nozzle 9 flows into the light combustion section 1 from the light inlet portion 7 and mixes with the primary air, and the lean premixed gas is ejected from the lean flame port 2. On the other hand, the fuel ejected from the rich nozzle 11 flows into the rich combustion section 3 from the rich inlet portion 10 and mixes with the primary air, and the rich premixed gas is ejected from the rich flame port 4. In addition, the secondary air was ejected from the secondary air outlet 6.

Then, the rich premixed gas is ignited by the ignition means 12 and immediately transferred to the lean premixed gas. Then, the flame detection means 13 detects the rich flame, and the operation of the combustion device is continued. Next, the rich premixed air has a high flame temperature, that is, it forms a stable rich flame with high NOx. On the other hand, the lean premixed gas has a low flame temperature, that is, it forms an unstable lean flame with low NOx, but it is low as a whole because heat energy is supplied from an adjacent rich flame to promote the combustion reaction. It realizes so-called rich and lean combustion that is NOx and stable.

[0006]

However, in the above-mentioned conventional structure, the light flame port 2 is used when extinguishing the fuel supply is stopped.
There was a problem that the light flame formed on the air blown off and odor was generated from the unburned lean premixed air. Furthermore, since the lean flame is stabilized by the thermal energy of the rich flame, the lean flame becomes unstable if the combustion ratio of the rich premixed gas is decreased (the combustion ratio of the lean premixed gas is increased). Become. That is, there is a problem that there is a limit to increase the combustion ratio of the lean premixed gas and further reduce NOx.

On the other hand, at the time of ignition for starting the fuel supply, there is a problem that the ignition performance is poor because the amount of rich premixed air is small. In addition, since the calorific value of the rich flame is small, there is a problem that the transfer to the lean premixed air is slow and odor is generated from the unburned lean premixed air.

Further, the opening area of the rich inlet portion 10 is smaller than that of the light inlet portion 7, a gap is provided between the rich inlet portion 10 and the rich nozzle 11, and the fuel and the primary air flow into the rich inlet portion 10 together. Therefore, when passing through this gap, the thick nozzle 11
Since a part of the fuel ejected from the fuel is flown into the primary air and does not enter the rich inlet portion 10, and thus the leaked fuel flows into the other lean inlet portions 7 and the rich inlet portion 10, there is a problem that the combustibility is deteriorated. Had.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a combustion apparatus which improves combustibility during fire extinguishing and prevents fuel leakage.

[0010]

In order to solve the above-mentioned conventional problems, a combustion apparatus of the present invention comprises a light inlet part for sucking fuel and air, a light combustion part composed of a light mixing chamber and a light flame port.
It is provided with a rich inlet portion for sucking in fuel, a rich combustion portion composed of a rich mixing chamber and a rich flame opening, and a communication port for communicating the light mixing chamber and the rich mixing chamber.

As a result, the fuel and air flowing into the lean inlet portion are mixed in the lean mixing chamber to form a lean premixed gas which is ejected from the lean flame port. On the other hand, the fuel that directly flows into the rich inlet portion mixes with the lean premixed gas that has flowed in through the communication port in the rich mixing chamber, and the rich premixed gas is ejected from the rich flame port. Next, the lean premixed mixture and the rich premixed mixture start to burn to realize rich and lean combustion. At the time of extinguishing the fuel supply, since the fuel flowing into the rich inlet has a low flow velocity, the rich flame holds longer than the lean flame. As a result, the rich flame holds the lean flame until the end, so the blowing of the lean flame is suppressed,
It is possible to prevent the generation of odor from an unburned lean premixed gas.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a light inlet part for sucking in fuel and air, a light combustion part composed of a light mixing chamber and a light flame port, a rich inlet part for sucking in fuel, and a rich inlet part. A rich combustion section including a mixing chamber and a rich flame port, and a communication port for communicating the light mixing chamber and the rich mixing chamber are provided.

As a result, the fuel and air flowing into the lean inlet portion are mixed in the lean mixing chamber to form a lean premixed gas which is ejected from the lean flame port. On the other hand, the fuel that directly flows into the rich inlet portion mixes with the lean premixed gas that has flowed in through the communication port in the rich mixing chamber, and the rich premixed gas is ejected from the rich flame port. Next, the lean premixed mixture and the rich premixed mixture start to burn to realize rich and lean combustion. At the time of extinguishing the fuel supply, since the fuel flowing into the rich inlet has a low flow velocity, the rich flame holds longer than the lean flame. As a result, the rich flame holds the lean flame until the end, so the blowing of the lean flame is suppressed,
It is possible to prevent the generation of odor from an unburned lean premixed gas.

The invention as defined in claim 2 is particularly defined by claim 1.
By opening a communication port that communicates the lean inlet portion with the rich mixing chamber in the combustion device described in (1), the fuel that directly flows into the rich inlet portion will flow through the communication port in the rich mixing chamber to the main portion of the lean inlet portion. To mix with air. The combustion ratio of the formed rich premixed gas can be set almost accurately by the amount of fuel directly flowing into the rich inlet portion. As a result, the change in the combustibility due to the change in the passage resistance of the air supply and the exhaust is small, and the combustibility of each combustion device is stable. Moreover, since the entire rich mixing chamber can be sufficiently used for mixing the fuel and air, the rich premixed air can be sufficiently mixed and the combustion characteristics can be improved.

The invention as defined in claim 3 is particularly defined by claim 1.
In the combustion apparatus described in (1), an intermediate combustion section that is composed of an intermediate mixing chamber and an intermediate flame port and communicates with the rich mixing chamber, and an intermediate communication port that communicates the light mixing chamber and the intermediate mixing chamber are opened.

Next, the lean premixed gas formed by mixing the fuel and air flowing into the lean inlet portion in the lean mixing chamber is ejected from the lean flame port. On the other hand, the fuel that directly flows into the rich inlet portion mixes with the lean premixed gas that has flowed in through the communication port in the rich mixing chamber, and the rich premixed gas is ejected from the rich flame port. Further, the rich premixture flowing into the intermediate mixing chamber from the rich mixing chamber has a fuel concentration intermediate between the lean premixed mixture and the rich premixed mixture formed by mixing with the lean premixed mixture flowing through the intermediate communication port. A certain intermediate premixed gas ejects from the intermediate flame outlet. Next, the lean premixed gas, the rich premixed gas, and the intermediate premixed gas start combustion to realize multi-concentration combustion. Next, the rich flame undergoes thermal decomposition by the intermediate flame, and a large amount of chemically active intermediate products are generated. Subsequently, the intermediate product is supplied to the base of the lean flame mouth by diffusion, and a "high temperature / high reaction zone" in which the combustion reaction is actively carried out is formed in the minute space of the base, thus stabilizing the lean flame. There is. Therefore, increasing the combustion ratio of the lean mixture,
Further, since the concentration of the lean air-fuel mixture can be reduced, NOx can be further reduced, the combustion amount variable range can be expanded and fuel can be achieved, and stable combustion can be realized by following high-speed air fluctuations.

The invention as defined in claim 4 is particularly characterized by claim 1.
By providing the ignition means on the downstream side of the lean flame opening of the combustion device described in (1), the lean premixed gas ejected from the lean flame opening is ignited by the ignition means, and the formed lean flame has a large combustion ratio and heat generation. Since the amount is large, the transfer to the rich premixture or other light premixture can be completed in a short time. As a result, the generation of odor from the unburned premixed air can be prevented.

The invention described in claim 5 is particularly characterized by claim 1.
Since the rich nozzle is provided so as to cover the rich inlet portion of the combustion device described in (1), the fuel directly flows into the rich inlet portion,
Fuel leakage can be prevented.

[0019]

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

(Embodiment 1) FIG. 1 is a side sectional view of a combustion apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a front sectional view thereof.

In FIG. 1 and FIG. 2, the lean burner section 20 comprises a lean inlet section 21 for sucking fuel and air, a lean mixing chamber 22 for mixing fuel and air, and a lean premixed mixture leaner than the stoichiometric air-fuel ratio. It is composed of an elongated thin flame outlet 23 for ejecting. The rich burner section 24 is provided so as to insert the lean burner section 20, and has a rich inlet section 25 for sucking the fuel, and the fuel and the lean mixing chamber 2.
It is composed of a rich mixing chamber 26 in which the two lean premixed gases are mixed, and an elongated rich flame port 27 for ejecting a rich premixed fuel in which the fuel is richer than the stoichiometric air-fuel ratio. Reference numeral 28 is a fuel dispersion port that connects the rich inlet portion 25 and the rich mixing chamber 26. A communication port 29 that connects the light mixing chamber 22 and the rich mixing chamber 26 is provided on the bottom surface of the light mixing chamber 22. An air chamber 30 communicating with a combustion fan (not shown) faces the fresh inlet portion 21. The light nozzle 31 that ejects fuel corresponds to the light inlet portion 21. The rich nozzle 32 for ejecting fuel is provided so as to cover the rich inlet portion 25. Reference numeral 33 is an L-shaped gas block provided with a light nozzle 31 and a dark nozzle 32.

The operation and action of the combustion device configured as described above will be described below.

First, the air blown from a combustion fan (not shown) flows from the air chamber 30 into the fresh inlet portion 21. Next, the fuel supplied to the gas block 33 and ejected from the light nozzle 31 flows into the light mixing chamber 22 from the light inlet portion 21 and mixes with the air, and the formed lean premixed gas is ejected from the light flame port 23. To do. Further, the fuel ejected from the rich nozzle 32 flows into the rich mixing chamber 26 from the rich inlet portion 25 through the fuel dispersion port 28. Subsequently, the fuel flowing into the rich mixing chamber 26 is mixed with the lean premixed gas flowing into the rich mixing chamber 26 from the communication port 29, and the formed rich premixed gas is ejected from the rich flame port 27. At regular times, a lean flame is formed at the lean flame port 23 and a rich flame is formed at the rich flame port 27, so that low NOx due to rich and lean combustion can be realized.

At the time of extinguishing the fuel while the fuel supply to the gas block 33 is stopped, the fuel flowing into the rich inlet portion 25 and having a slow flow velocity retains the rich flame longer than the lean flame. As a result, since the rich flame holds the lean flame to the end, blowout of the lean flame is suppressed, and the generation of odor from the unburned lean premixed air can be prevented.

As described above, in this embodiment, the lean inlet portion 21 for sucking in fuel and air, the lean burner portion 20 composed of the lean mixing chamber 22 and the lean flame port 23, and the rich inlet portion for sucking in fuel. 25, a rich combustion chamber 26 and a rich flame outlet 27, and a communication port 29 that communicates the light mixing chamber 22 and the rich mixing chamber 26. Since the flow velocity of the fuel flowing in and accumulated is slow, the rich flame holds the lean flame until the end. As a result, the blowout of the light flame is suppressed, and the generation of odor from the unburned lean premixed gas can be prevented.

(Embodiment 2) FIG. 3 is a side sectional view of a combustion apparatus according to Embodiment 2 of the present invention.

In FIG. 3, the difference from the configuration of the first embodiment is that a communication port 36 for communicating the light inlet portion 34 and the rich mixing chamber 35 is opened at the upper portion of the light inlet portion 34.

The operation and action of the combustion device constructed as above will be described below.

Then, the air blown from the combustion fan (not shown) and the fuel jetted from the light nozzle 31 flow into the light mixing chamber 22 through the light inlet portion 35 and are mixed with each other, and the lean premixed air mixture forms the light flame port 23. Gushes from. At that time, air mainly flows near the inner surface of the light inlet portion 35, and this air (a little fuel) flows into the rich mixing chamber 35 from the communication port 36. Further, the fuel ejected from the rich nozzle 32 flows into the rich mixing chamber 35 from the rich inlet portion 25 through the fuel dispersion port 28. Subsequently, the fuel flowing into the rich mixing chamber 35 is mixed with the air flowing into the rich mixing chamber 35 from the communication port 36, and the rich premixed air thus formed forms the rich flame port 2
Eject from 7. In particular, since the combustion ratio of the formed rich premixed gas can be set almost accurately by the amount of fuel that directly flows into the rich inlet portion, the change in the combustibility due to the change in the air supply or exhaust passage resistance is small, and The flammability of the device becomes stable. Furthermore, since the communication port 36 faces the upstream side of the rich mixing chamber 35, the rich mixing chamber 35 can be sufficiently used for mixing fuel and air. As a result, the rich premixed mixture can be sufficiently mixed and the combustion characteristics can be improved.

As described above, in the present embodiment, by opening the communication port 36 that communicates the light inlet portion 34 and the rich mixing chamber 35, the combustion ratio of the rich premixed gas can be set almost accurately. Moreover, the rich premixed air can be sufficiently mixed and the combustion characteristics can be improved.

The same effect can be obtained even if the communication port 36 is surrounded by the rich mixing chamber 35 and opened on the side surface of the light inlet portion 34.

(Embodiment 3) FIG. 4 is a sectional view of a combustion apparatus according to Embodiment 3 of the present invention.

In FIG. 4, the structure different from that of the first embodiment is composed of an intermediate mixing chamber 37 and an intermediate flame port 38, and an intermediate combustion section 40 communicating with the rich mixing chamber 39, and a light mixing chamber 41. The point is that an intermediate communication port 42 that communicates with the intermediate mixing chamber 37 is opened.

The operation and action of the combustion device configured as described above will be described below.

Then, the fuel and air flowing into the light inlet portion 21 are mixed in the light mixing chamber 22 to form a lean premixed gas, which is ejected from the light flame port 23. On the other hand, the fuel that directly flows into the rich inlet portion 25 is ejected from the rich flame outlet 27 in the rich mixing chamber 26, which is formed by mixing with the preceding lean premixed gas that flows in through the communication port 29. Further, the rich premixed air flowing from the rich mixing chamber 26 into the intermediate mixing chamber 37 is mixed with the lean premixed air flowing through the intermediate communication port 42, and is formed between the lean premixed air and the rich premixed air. The intermediate premixed gas, which is the fuel concentration, is ejected from the intermediate flame port 38. Then, the lean premixed gas, the rich premixed gas, and the intermediate premixed gas start combustion, and multi-concentration combustion is realized. At that time, the rich flame undergoes thermal decomposition by the intermediate flame, and a large amount of chemically active intermediate products are generated. Subsequently, the intermediate product is supplied to the base of the lean flame port 23 by diffusion, and a "high temperature / high reaction zone" in which the combustion reaction is actively carried out is formed in the minute space of the base, so that the lean flame is stabilized. ing. Therefore, since the combustion ratio of the lean air-fuel mixture can be increased and the concentration of the lean air-fuel mixture can be reduced, the NOx can be further reduced, the variable range of the combustion amount can be expanded, the fuel can be increased, and the high speed fluctuation of the air can be achieved. Can be followed to achieve stable combustion.

As described above, in the present embodiment, the intermediate combustion section 40 which is composed of the intermediate mixing chamber 37 and the intermediate flame port 38 and communicates with the rich mixing chamber 39, the light mixing chamber 41 and the intermediate mixing chamber 3 are connected.
By opening the intermediate communication port 42 communicating with 7, the stable lean flame can be obtained and the combustion ratio of the lean air-fuel mixture can be increased, so that the NOx can be further reduced.

(Embodiment 4) FIG. 1 is a block diagram of a combustion apparatus according to Embodiment 4 of the present invention.

In FIG. 1, what is added to the configuration of the first embodiment is that an ignition means 43 composed of an ignition electrode is provided on the downstream side of the light flame port 23.

The operation and action of the combustion device configured as described above will be described below.

Then, the lean pre-mixture formed by mixing the fuel and air flowing into the light inlet portion 21 in the light mixing chamber 22 is ejected from the light flame port 23. On the other hand, the fuel that directly flows into the rich inlet portion 25 is ejected from the rich flame outlet 27 in the rich mixing chamber 26, which is formed by mixing with the preceding lean premixed gas that flows in through the communication port 29. At that time, at the time of ignition when the fuel supply to the gas block 33 is started, the fuel flowing into the rich inlet portion 25 and accumulated therein has a low flow velocity, so that the lean premixed gas comes out from the lean flame port 23 earlier than the rich premixed gas. Gush out. Therefore, the lean premixed gas is ignited by the ignition means 43, and the formed lean flame has a large combustion ratio and a large calorific value, so that the transfer to the rich premixed gas or another light premixed gas is short. It can be completed in time. As a result, the generation of odor from the unburned premixed air can be prevented.

As described above, in this embodiment, since the ignition means 43 is provided on the downstream side of the light flame port 23, the generation of odor from the unburned premixed air can be prevented.

(Embodiment 5) FIG. 5 is an enlarged sectional view of a main part of a combustion apparatus according to Embodiment 5 of the present invention.

In FIG. 5, parts different from those of the first embodiment are ring-shaped sealing means 4 such as silicon or rubber.
4 through the thick nozzle 46 so as to cover the thick inlet portion 45
That is the point.

The operation and action of the combustion device configured as described above will be described below.

The air blown from the combustion fan (not shown) flows from the air chamber 30 into the fresh inlet portion 21.
Next, the fuel supplied from the gas block 33 and ejected from the light nozzle 31 passes through the air chamber 30 and flows into the light inlet portion 21. Further, the fuel ejected from the rich nozzle 46 directly flows into the rich inlet portion 45. In other words, the sealing means 44 prevents the air from accidentally flowing into the rich inlet portion 45 from the air chamber 30, so that the fuel leakage due to the air can be prevented. In particular, even if an assembly error occurs between the thick nozzle 46 and the thick inlet portion 45, the sealing means 44 plays the role of a cushioning material and the effect can be maintained.

As described above, in the present embodiment, the fuel leakage can be prevented by providing the rich nozzle 46 so as to cover the rich inlet portion 45 via the sealing means 44.

[0047]

As described above, according to the invention described in claims 1 to 5, it is possible to improve the combustibility at the time of extinguishing a fire and prevent the fuel leakage.

[Brief description of drawings]

FIG. 1 is a side sectional view of a combustion device according to first and fourth embodiments of the present invention.

FIG. 2 is a front sectional view of the combustion device according to the first embodiment of the present invention.

FIG. 3 is a side sectional view of a combustion device according to a second embodiment of the present invention.

FIG. 4 is a side sectional view of a combustion device according to a third embodiment of the present invention.

FIG. 5 is an enlarged sectional view of an essential part of a combustion device according to a fifth embodiment of the present invention.

FIG. 6 is a side sectional view of a conventional combustion device.

FIG. 7 is a front sectional view of the device.

[Explanation of symbols]

20 Light burning part 21, 34 Fresh entrance 22, 41 Light mixing chamber 23 light flame mouth 24 Light burning part 25, 45 dense entrance 26, 35, 39 dense mixing chamber 27 Thick flame mouth 29, 36 communication port 37 Intermediate mixing chamber 38 Intermediate flame mouth 40 Intermediate combustion section 42 Middle communication port 44 Seal material 46 dense nozzle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor hair group             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3K017 AA01 AA06 AC02 AG00 CA00                       CB08 CE00                 3K065 TA01 TA14 TD05 TH03 TH04

Claims (5)

[Claims] 1. A lean combustion section comprising a lean inlet section for sucking fuel and air, a lean mixing chamber and a lean flame opening, and a rich combustion section comprising a rich inlet section for sucking fuel, a rich mixing chamber and a rich flame opening. And a communication port that connects the light mixing chamber and the rich mixing chamber. 2. The combustion device according to claim 1, wherein a communication port that communicates the light inlet portion and the rich mixing chamber is opened. 3. An intermediate combustion section which is composed of an intermediate mixing chamber and an intermediate flame port and which communicates with the rich mixing chamber, and an intermediate communication port which communicates between the light mixing chamber and the intermediate mixing chamber are opened. The combustion device according to 1. 4. The combustion device according to claim 1, wherein an ignition means is provided on the downstream side of the light flame port. 5. The combustion device according to claim 1, further comprising a rich nozzle so as to cover the rich inlet portion via a sealing means.