JPH0367910A - Low nox burner - Google Patents

Abstract

PURPOSE:To achieve low NOx of flame as a whole by providing fins for cooling walls of a first stage combustion chamber on a second stage firing burner to reduce NOx of the first stage flame. CONSTITUTION:Mixed gas in a mixed gas room 10 is blown off from burner ports 2 of a first stage burner port section 3, whereby first stage flames are formed at the burner ports 2 in a first stage combustion chamber 5. In the first stage combustion chamber 5, mixed gas having a volume corresponding to a primary air ratio equal to that of the mixed gas in the mixed gas room 10 is burnt and unburnt fuel is mixed with secondary air and burnt at a second stage burner port section 8. In this case, heat produced from the first stage flames which are formed in the first stage combustion chamber 5 is transferred through a first stage combustion chamber wall 4 to fins 9 for cooling the first stage combustion chamber wall to release the heat to the secondary air flowing between burners. In this manner, temperatures of the first stage combustion chamber 5 can be lowered, and hence temperatures of the first stage flames can be decreased, so that amount of NOx generation can be greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a Bunsen type low NOx burner.

2. Description of the Related Art Conventionally, as shown in FIG.
It has a first stage combustion chamber 24 provided from both sides of the mixture chamber 21 to the top of the first stage flame port 23, and a first stage flame is formed in the first stage combustion chamber 24. After combustion, a second-stage flame is formed in the second-stage flame port 25 at the upper part of the first-stage combustion chamber 24 and complete combustion occurs, thereby burning the flame in two stages, lowering the flame temperature, and suppressing the generation of thermal NOx. It was being prevented.

Problems to be Solved by the Invention However, with the above configuration, the heat generated by the first stage flame formed in the first stage combustion chamber is difficult to dissipate because it is surrounded by the first stage combustion chamber, and the heat generated by the first stage flame is difficult to radiate. Lowering the temperature and reducing NOx generated from the flame was not sufficient.

The present invention solves this conventional problem by providing fins for cooling the wall of the first stage combustion chamber on the outside of the first stage combustion chamber.
The heat generated by the first stage flame is radiated through the first stage combustion chamber wall to the secondary air flowing between the burners through the first stage combustion chamber wall cooling fins, and the salinity of the first stage flame is lowered to reduce the temperature. This reduces the generation of NOx. Therefore, by reducing NOx in the first stage flame, which accounts for about 1/2 of the combustion amount, it is possible to reduce NOx in the entire flame.

Means for Solving the Problems In order to solve the above problems, the low NOx burner device of the present invention includes a mixture chamber, a first-stage flame port section comprising a number of flame ports provided downstream of the mixture chamber, and A two-stage combustion burner having a first-stage combustion chamber provided from both sides of the air chamber to the top of the first-stage flame port, and a second-stage flame port above the first-stage combustion chamber,
The combustion chamber is provided with fins for cooling the wall of the first stage combustion chamber on the outside of the first stage combustion chamber.

Function: With the above-described configuration, the present invention radiates heat generated from the first-stage flame through the first-stage combustion chamber to the secondary air flowing between the burners from the first-stage combustion chamber wall cooling fins outside the first-stage combustion chamber. However, by lowering the first stage flame temperature, the generation of thermal NOx is reduced. Therefore, by reducing NOx in the first stage flame, which accounts for about 1/2 of the combustion amount, it is possible to reduce NOx in the entire flame.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

In FIGS. 1 and 2, 1 is a burner main body, and on the upper surface of the burner main body 1 there is a first stage burner port 3 having a large number of burner ports 2 opened therein. The first stage flame port part 3 is formed in a mountain shape or semi-cylindrical shape with the apex at the center, and the flame ports 2 are provided on both inclined surfaces with the apex in between. A first-stage combustion chamber wall 4 is provided in the longitudinal direction above the first-stage flame port 3 from both sides of the burner body 1, and a first-stage combustion chamber 5 is formed inside the first-stage combustion chamber wall 4. The upper end of the first combustion chamber wall 4 is bent inward to form a horizontal portion 6, and a second flame portion 8 is formed between the horizontal portions 6 and 7. Fins 9 for cooling the first stage combustion chamber wall are provided on the outside of the first stage combustion chamber wall 4. 10 is a mixture chamber.

In the above configuration, the air-fuel mixture inside the air-fuel mixture chamber 10 is ejected from the flame port 2 of the first-stage flame port portion 3, and forms a first-stage flame at the flame port 2 within the first-stage combustion chamber 5. In the first stage combustion chamber 5, a mixture corresponding to the primary air ratio, which is the same as the 7-component mixture in the mixture chamber 10, is combusted, and the unburned phosphorus fuel is in the second stage flame port 8. Mixes with secondary air and burns. The secondary air flows between the burner body 1 and other burner bodies installed in parallel from the bottom to the top, flows along the outer periphery of the first stage combustion chamber 5, and is moved between the horizontal parts 7 and the second stage flame. Supplied as secondary air.

Therefore, the flame formed in the burner with the above configuration consists of a first stage flame formed in the flame port 3 and a second stage flame formed in the second stage flame port 8 above the first stage flame. Here, the principle of generation of NOx generated from flame will be explained. NOx generated from flames generally includes two types: thermal NOx and thermal NOx, and the amount of prompt NOx generated depends on the fuel. Thermal NOx is NOx produced by reaction of N2 in the air when passing through a flame reaction zone, and the amount of thermal NOx generated is determined by the temperature of the flame reaction zone.

Note that the amount of thermal NOx generated decreases as the temperature of the flame reaction zone decreases. Therefore, if the flame is divided into two stages, the 1st stage flame and the 2nd stage flame, and the temperatures of the 1st stage flame and the 2nd stage flame are lowered to cause combustion, the reaction will be slow and the flame reaction zone will become large. The temperature of the flame reaction zone is lowered, and NOx can be reduced. Therefore, the heat generated by the first stage flame formed in the first stage combustion chamber 5 by the burner having the above configuration is transferred to the first stage combustion chamber wall cooling fins 9 via the first stage combustion chamber wall 4, and the burner is heated. By dissipating heat to the secondary air flowing between them, the temperature of the first stage combustion chamber 5 can be lowered, and the temperature of the first stage flame can be reduced, which has the effect of significantly reducing the amount of NOx generated.

Effects of the Invention As described above, according to the low NOx burner device of the present invention, by providing the two-stage combustion burner with fins for cooling the first-stage combustion chamber wall, heat generated from the first-stage flame is transferred to the first-stage combustion chamber wall. Heat is radiated to the secondary air flowing between the burners from the fins for cooling the walls of the first stage combustion chamber outside the first stage combustion chamber, and the temperature of the first stage flame is lowered, reducing the generation of thermal NOx and reducing combustion. By reducing NOx in the first stage flame, which accounts for about 1/2 of the amount, it is possible to achieve the effect of reducing NOx in the entire flame.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of essential parts of a low NOx burner according to an embodiment of the present invention, FIG. 2 is a perspective view of the same, and FIG. 3 is a perspective view of a conventional burner. 2...flame mouth, 3...first stage flame mouth part, 5
...First stage combustion chamber, 8...Second stage flame opening, 9...Fins for cooling the first stage combustion chamber wall, ■
0...Mixture chamber.

Claims (1)

[Claims] a mixture chamber, a first stage combustion chamber including a plurality of flame ports provided downstream of the mixture chamber, a first stage combustion chamber provided from both sides of the mixture chamber to an upper part of the flame port, and the first stage combustion chamber; A two-stage combustion burner having a second-stage flame port in the upper part of the combustion chamber, and a low NO_x burner in which fins for cooling the wall of the first-stage combustion chamber are provided outside the first-stage combustion chamber.