JP3049963B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for reducing NOx.

[0002]

2. Description of the Related Art In a conventional combustion apparatus, a lean-burn combustion system in which a lean gas combustion flame having a high excess air ratio is flame-stabilized by a rich gas combustion flame having a low excess air ratio and having a flame-stabilizing action, and is stably burned. Gas burners are well-known, and a flame using a lean gas has a low flame temperature, can eliminate local high-temperature portions, reduce NOx, stabilize combustion, and reduce noise.

[0003] The gas burner of the lean-burn type has conventionally been
For example, as shown in FIG. 3, a combustion inner pipe 25 is disposed at the center of a combustion pipe 21 forming an mixing chamber 24 having an opening 22 at an upper part and a secondary air port 23 at a lower part. Tube 25
A dense gas flame hole 26 is provided on the upper surface of the mixture, a through hole 27 is provided on the lower side surface, and a light gas flame port 28 is provided on the upper part of the mixing chamber 24 so that a rich flame is formed at the center and a light flame is formed on both sides. It is burned.

[0004]

However, in the prior art, when a plurality of the combustion tubes 21 are arranged side by side in the burner case 29, the light-side flame of the combustion tube 21 at the center portion is stably sandwiched between the rich-side flames. However, the light-side flames at both ends are lifted and become unstable, unburned gas is generated, and the burner case 29
However, there is a problem that the burner case 29 is overheated due to the contact of the flame.

An object of the present invention is to solve the above-mentioned problems and to provide a combustion apparatus which stably burns the light-side flames at both ends and does not cause problems such as generation of unburned gas and overheating of the burner case. is there.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a combustion chamber having an opening at an upper portion and a secondary air port at a lower portion of a combustion tube forming a mixing chamber. A combustion gas pipe having a dense gas flame hole on the upper surface of the inner combustion tube, a through hole on the lower side surface, and a light gas flame port on the upper part of the mixing chamber. Are closed at the secondary air ports of the combustion pipes at both ends of a burner case having a plurality of burners installed therein.

[0007]

[Function] During combustion, a rich gas flame is formed in the rich gas flame hole at the center of the combustion tube, and the gas ejected into the mixing chambers on both sides has a lower gas flame.
The secondary air that flows in from the secondary air port mixes, generates a lean gas, and blows out and burns from the upper lean gas flame port to form a lean gas flame on both sides of the rich gas flame. Since secondary air does not flow into the secondary air ports of the combustion tubes at both ends in the burner case due to the closing plate, a rich gas flame is formed in the upper flame port, and the flame port fixing property is high and lifting is prevented. Thus, generation of unburned gas can be eliminated. Moreover, the secondary air, which has been prevented from flowing into the combustion tube by the blocking plate, flows into the gap between the combustion tube and the burner case, so that an air flow is generated along the inner surface of the burner case, and the flame is deflected in the direction of the burner case. As a result, the burner case is cooled by the air flow, thereby preventing the burner case from overheating.

[0008]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

Reference numeral 1 denotes a combustion tube having an opening 2 at an upper portion, a mixing chamber 4 having a secondary air port 3 opened at a lower portion, and a combustion inner tube 5 arranged at a central portion so as to divide the mixing chamber 4. A plurality of the combustion tubes 1 are arranged side by side to constitute a gas burner. In the combustion inner pipe 5, a concentrated gas having a low excess air ratio, which is a mixture of fuel gas and primary air, flows therein, and a concentrated gas flame hole 6 provided on the upper surface.
The fuel is blown out of the mixing chamber 4 and is blown out into the mixing chamber 4 through a through hole 7 provided in the lower side surface. Reference numeral 8 denotes a venturi section formed in the mixing chamber 4, which mixes the secondary air flowing from the secondary air port 3 below the combustion pipe 1 with the mixed gas ejected from the through-hole 7, to produce a fresh gas having a high excess air ratio. Generate. Reference numeral 9 denotes a light gas flame port provided in the upper part of the mixing chamber 4, the inside of the opening 2 is separated by a partition plate 10 arranged side by side with a gap, and the dense gas flame hole 6 in the center is sandwiched on the upper surface of the combustion tube 1. A light gas flame port 9 is formed on both sides. Reference numeral 11 denotes a burner case in which a plurality of the combustion tubes 1 are provided. Reference numeral 13 denotes a closing plate attached so as to close the inlet of the secondary air port 3 on the fresh gas side located on the burner case 11 side of the combustion tube 1 at both ends inside the burner case 11. Is burned with a rich gas flame so as not to flow.

In the above configuration, at the time of combustion, the dense gas having a low excess air ratio in the combustion inner pipe 5 is ejected from the dense gas flame hole 6 on the upper surface and burns, and the secondary gas port 3 is supplied to the ejected gas from the through hole 7. The secondary air that has flowed in uniformly from above is mixed well by the venturi section 8 of the mixing chamber 4 and is homogenized to produce a lean gas having a high excess air ratio, which is ejected from the lean gas flame port 9 to shorten the flame. Combustes to form main flame. The light gas flame is stably burned by the flame holding action of the rich gas flame.

The secondary air ports 3 located on the burner case 11 side of the combustion tube 1 at both ends inside the burner case 11
3, the dense gas is supplied to the light gas side flame port, and a dense gas flame having high flame port fixing property is formed. Since lifting is not performed, generation of unburned gas can be prevented. . Moreover, the closing plate 13 allows the inflowing air from below to appropriately flow between the burner case 11 and the combustion tube 1 to prevent the flame from deflecting toward the burner case 11 and prevent the burner case 11 from overheating.

As described above, it is possible to reduce the NOx by eliminating the generation of the local high-temperature portion by the concentration combustion, and it is possible to perform the stable combustion, and to make the combustion flame at both ends on the burner case side into a rich gas flame. It is possible to prevent lifting of the flame of the portion and to eliminate generation of unburned gas.

Incidentally, as shown in FIG. 2, even when the capacity is switched by switching the number of combustion tubes in the combustion tube 1,
When the capacity is low, the closing plate 13 may be attached to the secondary air ports 3 of the combustion pipes 1 at both ends as described above.

[0014]

As described above, according to the present invention, a combustion tube having a dense gas flame hole at the center and a light gas flame hole formed at both sides thereof is used as a secondary combustion tube at both ends of a burner case. Since the air port is closed by the closing plate, a lean gas flame is not formed on the burner case side, and a rich gas flame is formed to prevent lifting and eliminate generation of unburned gas. The burner case can be prevented from being overheated by the action of the secondary air flow that is prevented from flowing into the combustion tube by the closing plate, so that NOx can be reduced by rich and lean combustion and noise can be reduced by stabilizing combustion. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a combustion apparatus showing one embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a combustion device when the present invention is applied to capacity switching.

FIG. 3 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion pipe 2 Opening 3 Secondary air port 4 Mixing chamber 5 Combustion inner pipe 6 Rich gas flame hole 7 Through hole 9 Light gas flame hole 11 Burner case 13 Closure plate

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-273905 (JP, A) JP-A-4-203703 (JP, A) JP-A-4-203702 (JP, A) JP-A-4-203 186004 (JP, A) JP-A-4-124512 (JP, A) JP-A-2-115627 (JP, U) JP-B-52-28251 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23D 14/02 F23D 14/08 F23C 11/00 329-330

Claims (1)

(57) [Claims] 1. A combustion inner pipe is provided at the center of a combustion pipe forming a mixing chamber having an opening at an upper part and a secondary air port at a lower part, and a rich gas flame is provided on an upper surface of the combustion inner pipe. A combustion tube is formed by providing a hole and a through hole in the lower side surface, and providing a fresh gas flame port in the upper portion of the mixing chamber, wherein two or more of the combustion tubes are provided at both ends of a burner case in which a plurality of the combustion tubes are provided. A combustion device comprising a closing plate attached to a secondary air port.