JP3109354B2 - 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 lean-burn combustion system.

[0002]

2. Description of the Related Art Conventionally, there is a rich-lean combustion system as one of the combustion systems for reducing NOx, and a rich-side mixture chamber that generates a rich mixture and supplies it to a rich-side flame hole, and a lean-side mixture is generated. A light-side mixing chamber that supplies the light-side flame holes, and stably burns the light flame that is formed in the light-side flame holes by the flame holding action of the dense flame that is formed in the dark-side flame holes. The lean flame of lean combustion, which eliminates the generation of high-temperature parts, occupies most of the combustion amount,
x generation is reduced.

[0003]

However, in such a burner, when the lean air-fuel mixture is not uniform and the amount of air is partially different, a part of the lean flame may be lifted, or the part where the amount of air is small may be reduced. There was a problem that the generation of NOx increased.

As an example of this, as shown in FIG. 4, a venturi portion 22 is provided below a combustion tube main body 21, and a nozzle holder 23 is arranged below the combustion tube main body 21 on one side.
In the configuration in which the air inlet 4 faces the gas inlet 25, the air entering the air port (not shown) of the upper light-side mixing chamber (not shown) is higher than the gas inlet 25 as compared with other portions. And the gas concentration of the light mixture tends to increase. As shown in FIG. 5, the excess air ratio PA of the lean mixture ejected from the lean flame hole above the gas inlet 25 is lower than the excess air ratio PB of the other portion of the lean mixture.
There is a problem that the amount of generated O increases. In addition, when there is such a portion having a different gas concentration, there is a problem that a margin for a change in a supplied gas amount or an air amount is small, and a control range is narrowed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a combustion apparatus which balances a gas amount or an air amount to a lean air-fuel mixture and widens a control range to stabilize combustion of a light flame.

[0006]

In order to achieve the above object, a combustion apparatus according to the present invention has a rich flame hole and a light flame hole, has a gas inlet for taking in fuel gas and primary air, and has a rich flame. A dark-side mixing chamber that supplies a rich mixture to the holes and a light-side mixing chamber that supplies a light-air mixture to the light flame holes are defined, and the rich mixture is supplied from the rich-side mixing chamber to the light-side mixing chamber. And a gas passage for supplying air to the light-side mixing chamber, wherein the amount of gas discharged from the light-side gas discharge hole located in the vicinity of the gas inlet is set at another position. This is one that is smaller than the amount of jet or that the air passage near the gas inlet is larger than the air passage at another position.

[0007]

In the light mixing chamber, the air from the air passage is mixed with the rich gas mixture from the light gas outlet provided in the rich mixing chamber to generate a light gas mixture. At this time, the amount of air is adjusted by widening the air passage near the gas inlet where air does not easily enter so that air can easily enter, or reducing the number of holes or the hole diameter of the light gas outlet near the gas inlet. Since the amount of gas is adjusted, the amount of gas and the amount of air are balanced, and the lift of light flame and the generation of NOx due to partial unevenness of the lean air-fuel mixture are prevented.

[0008]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG.
Is a cross-sectional view of the same example, and FIG. 3 is a cross-sectional view taken along line AA shown in FIGS.

Reference numeral 1 denotes a combustion tube, which has a light mixing chamber 2 formed in the center and a dense gas chamber 3 formed on both sides thereof, and a light flame hole forming member 4 is attached to the upper opening of the light mixing chamber 2 to form a light flame hole. 5 and a rich flame hole 6 is provided above the rich gas chamber 3. Reference numeral 7 denotes a rich-side mixing chamber for supplying a rich air-fuel mixture to the combustion pipe 1. The rich-side mixing chamber 7 is connected to the combustion pipe 1 by a connecting part 8 formed on the side wall of the rich-gas chamber 3 below the light-side mixing chamber 2. The communicating hole 9 communicates with the concentrated gas chamber 3. Reference numeral 10 denotes an air passage formed between the connection portion 8 between the rich-side mixing chamber 7 and the combustion tube 1, and communicates an air port 11 provided at a lower portion with the light-side mixing chamber 2. 1
Reference numeral 2 denotes a light-side gas ejection hole provided on a side surface of the rich-side mixing chamber 7 corresponding to the air passage 10, and supplies a rich air-fuel mixture to the light-side mixing chamber 2 through the air passage 10 and is supplied from an air port 11. Mixed with air to produce a light mixture. The air passage 10 has a gas inlet side, which will be described later, where air is difficult to enter. Therefore, the gap B of the air passage 10 in this portion is widened to make it easier for air to enter, and the balance of the amount of air flowing into the light-side mixing chamber 2 is improved. It has been adjusted as follows. Reference numeral 13 denotes a throttle portion provided to allow the rich mixture to flow uniformly through the rich flame hole 6, and 14 denotes a venturi portion provided in the combustion tube main body 7, and a notch portion 15 provided on one side below the rich side mixing chamber 7. A nozzle 18 having a gas inlet 16 and attached to a nozzle holder 17 disposed in the cutout 15 is connected to the gas inlet 16.
It is facing. A plurality of light-side gas ejection holes 12 are provided on the corresponding surface of one air passage 10, and the pitches a and b are changed so that a <b, so that mixing of gas and air is promoted. To make the light flame uniform.

According to the present invention, when gas is ejected from the nozzle 18 by the above configuration, the gas inlet 1 is formed by the venturi portion 14.
Air is sucked from 6, and a rich mixture having a low excess air ratio is generated in the rich side mixing chamber 7. The rich mixture flows into the rich gas chamber 3 of the combustion tube 1 from the through hole 9 and is supplied to the rich flame hole 6 at the upper portion to form a rich flame. The rich mixture injected into the air passage 10 from the light-side gas outlet 12 is mixed with the air from the air port 11 in the light-side mixing chamber 2 to generate a light mixture, which is supplied to the upper light-flame hole 5. Being formed a pale flame. Air port 11
Is difficult to enter the gas inlet 16 side,
In the present embodiment, since the gap B of the air passage 10 on the gas inlet 16 side is widened, the air does not flow into the light-side mixing chamber 2 as in the other parts and the air in the light-side mixing chamber 2 has a different amount. Improves flame balance and prevents lift and NOx generation.

Incidentally, since it is difficult for air to enter the gas inlet 16 side, in this embodiment, the gap B of the air passage 10 is widened to improve the inflow of air to achieve balance. The number of the light-side gas ejection holes 12 facing the air passage 10 on the 16 side is reduced (for example, three in this embodiment, but the number is reduced to two), and the gas amount is reduced to balance with the air amount. You may take it.

Instead of reducing the number of holes in this portion, the diameter of the holes may be reduced to balance the whole.

[0013]

As described above, according to the present invention, the amount of gas or air in the lean mixture is adjusted by adjusting the amount of gas or air on the gas inlet side to the lean-side mixing chamber. Are eliminated, the combustion range is widened, the light flame becomes uniform, and the generation of NOx can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention.

FIG. 2 is a sectional view of the same example.

FIG. 3 is a sectional view taken along the line AA shown in FIGS.

FIG. 4 is a side view of a main part showing a conventional example.

FIG. 5 shows the excess air ratio of lean air-fuel mixture and NOx and CO in a conventional example.
FIG. 6 is an explanatory diagram showing a relationship with the amount of occurrence of the swelling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion pipe 2 Light side mixing chamber 5 Light flame hole 6 Rich flame hole 7 Rich side mixing chamber 10 Air passage 11 Air port 12 Light side gas ejection hole 16 Gas inlet 17 Nozzle holder

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-19420 (JP, A) JP-A-7-42913 (JP, A) JP-A-6-34110 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F23D 14/02-14/08 F23D 14/62 F23C 11/00 329-330

Claims (1)

(57) [Claims] 1. A rich-side mixing chamber having a rich flame hole and a light flame hole, having a gas inlet for taking in fuel gas and primary air, and supplying a rich air-fuel mixture to the rich flame hole. A light-side mixing chamber that supplies a light-air mixture is defined, and a light-side gas ejection hole that supplies a rich-air mixture from the rich-side mixing chamber to the light-side mixing chamber is provided, and air is supplied to the light-side mixing chamber. Forming an air passage that reduces the amount of gas ejected from the light-side gas ejection hole located near the gas inlet from the amount of ejection at another position, or reduces the amount of air ejected from the gas inlet near the gas inlet to another position. A combustion device characterized by being enlarged from an air passage.