JP2622478B2 - Light-burn combustion burner - 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 burner which generates a small amount of NO2.

[0002]

2. Description of the Related Art Excessive air-fuel mixture is discharged from a main flame port, and rich fuel-air mixture is discharged from a sleeve flame port adjacent to the main flame port to perform rich-lean combustion.
There has been conventionally known a concentration combustion burner in which the emission is reduced (JP-A-3-263505).

[0003]

However, in the conventional burn-in-contrast burner, a main burner having a main flame port and a sub-burner having a sleeve flame port are separately provided, and therefore, a lean mixture is supplied to the main burner. However, gas supply means such as a nozzle for supplying a rich air-fuel mixture to the sub-burner are required separately, and the structure is complicated, and the production cost is high.

[0004] It is an object of the present invention to provide a lean-burn burner having a simple structure and a low production cost.

[0005]

In order to solve the above-mentioned problems,
The present invention is directed to a main passage from which an air-excess lean mixture is discharged from a slit-shaped main flame port, and a slit-shaped sleeve flame port located on both sides of the main passage and adjacent to both sides of the main flame port. A sub-passage through which an excess fuel-rich mixture is discharged,
A rich / burn combustion burner in which a branch hole communicating with the sub-passage is formed in a main passage wall, wherein the main passage from which the light-air mixture is discharged joins a gas mixture passage for supplying a rich mixture and an air supply passage. The junction was set downstream of the branch hole.

[0006]

The rich fuel-fuel mixture flows through the gas mixing passage, and enters the sub-passages located on both sides of the main passage through branch holes formed in the main passage wall. Excess fuel rich mixture is discharged from the slit-shaped sleeve flame ports adjacent to both sides of the main flame port, and excessive fuel combustion occurs. The gas mixing passage and the air supply passage having the excess air blowing hole are merged on the downstream side of the branch hole to form a main passage, and a lean air mixture with excess air is discharged from the slit-shaped main flame port, and the lean combustion is performed. I do. Since the junction is set on the downstream side of the branch hole, no air is mixed into the rich mixture entering the sub-passage.

[0007]

According to the present invention, it is possible to form a main flame port for performing lean combustion and a sleeve flame port for performing excess fuel combustion on both sides of the main flame port for performing rich and light combustion in one gas mixing passage. For this reason, the structure of the lean burn burner is simplified, and the lean burn burner can be manufactured at low cost.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 2A shows a low NO gas employing the configuration of the present invention.
The {burner, low NO} burner A is arranged at predetermined intervals, and is fixed below the heat exchanger 11 of the water heater 1 shown in FIG. 3 by a fixing member. In the water heater 1, 1
2 is a proportional valve for adjusting the gas supply amount, 13 is a gas supply pipe for supplying gas to the nozzle N, and 14 is a fan for supplying combustion air to the low NOχ burner.

A low NO burner A manufactured by joining sheet metals is provided with a main passage 2 for discharging lean air-fuel mixture 15 with excess air from a main flame port 21 at an upper end to perform lean combustion, and a sleeve flame port 3 at an upper end.
A sub-passage 3 for discharging an excess fuel rich mixture 16 from 1 to burn excess fuel, and an air supply passage 4 disposed in the main passage 2
And a gas mixing passage 5 for supplying a rich mixture 16 into the main passage 2 and the sub passage 3.

At the upper end of the main passage 2 having a rectangular cross section, a number of slit-shaped main flame ports 21 are formed. At the upper end of the sub passage 3, a plurality of main flame ports 21, 21.
The slit-shaped sleeve flame ports 31, 31 are formed on both sides of the main flame ports 21, 21,. A branch hole 32 communicating the sub-passage 3 and the main passage 2 penetrates a lower end of a wall separating the two passages, and is provided laterally. The rich mixture 16 is supplied from the branch hole 32 into the sub-passage 3. Is done.

An air supply passage 4 for supplying air 40 into the main passage 2 is provided laterally in the main passage 2 such that the excess air outlet 41 is located downstream of the branch hole 32.
The air ejected from 1 becomes primary air, is mixed with the rich mixture 16 in the main passage 2, and is diluted to become a lean mixture with excess air. The internal pressure in the air supply path 4 is set to be higher than the internal pressure in the main passage 2 due to the wind blast of the fan 14 and the like, and the air 40 is ejected from the excess air outlet 41 into the main passage 2 and the amount thereof is By adjusting the opening area of the air suction port 42 at the most upstream end of the air supply path 4 by a damper or the like, the excess air ratio for lean combustion at the main flame port 21 (for example, 1.
4) is set.

The substantially J-shaped gas mixing passage 5 has a primary air suction port 51 formed at the base end thereof. A nozzle N for ejecting gas faces the suction port 51, and a small amount of primary air and gas are supplied. The mixed fuel-rich rich mixture 16 (for example, an excess air ratio of 0.
8) is supplied to the gas mixing path 5.

Gas is supplied from the gas supply pipe 13 to the nozzle N, and the gas ejected from the nozzle N enters the gas mixing path 5 together with the primary air sucked from the primary air suction port 51, and a predetermined excess amount of fuel is provided. The rich mixture 16 is supplied into the low NO burner A.

The rich mixture 16 in the gas mixing passage 5
The fuel is supplied into the sub-passage 3 from the sub-passage 2 and discharged from the sleeve flame port 31 to burn excess fuel. Also, the rich mixture 1 in the gas mixing path 5
6 is supplied into the main passage 2, and from the excess air blowing hole 41,
A predetermined flow rate of air 40 is blown into the main passage 2, and the rich mixture 16 in the main passage 2 is diluted to a predetermined excess air concentration, so that the light mixture 15 is discharged from the main flame port 21, Burns lean.

Since rich and light combustion is performed by the main flame port 21 and the sleeve flame port 31, the amount of NO in the exhaust gas is reduced to 60 PPM.
It can be suppressed to the following.

Since gas can be supplied to the sub-passage 3 and the main passage 2 by one nozzle N and one gas mixing passage 5, the structure under the burner can be simplified.
Low NO burner A can be manufactured at low cost.

The rich mixture supplied from the suction port 51 may be a gas not containing primary air. In this case, a communication hole is provided in a wall separating the main passage 2 and the sub-passage on the downstream side of the excess air blowing hole 41 to mix the lean mixture in the excess air main passage 2 with the gas in the sub-passage 3. Either a fuel-rich rich mixture is blown out from the sleeve flame outlet, or a small air blowout hole for blowing out a small amount of air 40 from the air supply passage 4 upstream of the branch hole 32 is provided. So that a rich mixture rich in fuel flows through the inside.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a low NO burner according to an embodiment of the present invention.

FIG. 2 is a perspective view of a combustion section of the gas water heater in which the low NOχ burner is assembled.

FIG. 3 is a schematic diagram of a gas water heater in which the low NOχ burner is assembled.

[Explanation of symbols]

 A low NO burner (concentration combustion burner) 2 main passage 3 sub passage 4 air supply passage 5 gas mixing passage 15 light mixture 16 rich mixture 21 main flame port 31 sleeve flame port 32 branch hole 41 excess air blowing hole

Claims (1)

(57) [Claims] From 1. A slit-shaped main flame ports and a main passage pale mixture excess air is discharged, as well as positioned on either side of the main passage, slit-like sleeve fire hole adjacent to each side of the main flame hole and a secondary passage excess fuel rich mixture is discharged from bored branch hole in the main passage wall in communication with the sub-passage shades
In the combustion burner, the main passage from which the lean mixture is discharged is formed by joining a gas mixture passage for supplying a rich mixture and an air supply passage.
The point burner is characterized in that the point is set downstream of the branch hole.