JPH04184006A - Burner - Google Patents

Abstract

PURPOSE:To make combustion slow and lower the flame temperature and provide low NOx combustion by supplying to the flame formed above a first flame port an oxygen mixture gas that is blown out of a second flame port and unburned and contains oxygen lower in concentration than the atmosphere. CONSTITUTION:A mixture gas in a first mixture gas chamber 14 is set at the primary air ratio of 30%-60%. Part of this mixture gas is blown out of a first flame port 7, and the rest of the mixture gas goes through a mixture gas channel 8 and is 1ed to a second mixture gas chamber 9. Secondary air flows between the burner main body 6 and the second mixture gas chamber that is provided parallel to it from the lower section to the upper section, and flows into the second mixture gas chamber 9 from an air intake port 13 to be mixed with the mixture gas from a mixture gas channel 8 to become a mixture gas in which the primary air ratio is about 170%-250% and which is lower than the limit of combustibility, and it is blown out from a second flame port 12. If the flame burns in a low oxygen concentration atmosphere, its reaction becomes slow, and the flame reaction band becomes large so that the quantity of heat generated per unit flame reaction band reduced. By this reason the flame reaction band temperature falls and NOx is reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a combustion device aiming at low NOx.

Conventional technology In recent years, various types of combustion equipment have been developed to improve the living environment.
There is a growing demand for x.

Conventionally, this type of combustion device was disclosed in Japanese Patent Application Laid-Open No. 108906/1986
There was something like the one shown in the publication. Hereinafter, its configuration will be explained based on FIG. 3. As shown in the figure, a premix burner 2 having one flame hole 1, a first box 4 that houses the premix burner 2 and is isolated from the atmosphere except for a secondary flame hole 3 formed at one end, and a It consists of a second box 5 which surrounds a first box 4 and has openings at both ends, and performs two-stage combustion to prevent the generation of NOx.

Problems to be Solved by the Invention In such a conventional combustion device, since a separate second box body 4 is required outside the first box body, the volume of the burner becomes very large and the load on the combustion chamber increases. The problem was that it was small.

The present invention solves the above problems, and aims to reduce the generation of NOx and enable high-load combustion.

Means for Solving the Problems In order to achieve the above objects, the combustion device of the present invention includes a burner body having a first flame port, a mixture passage, and a first mixture chamber, and a burner body having a first flame opening, a first mixture passage, and a first mixture chamber. A wall material forming one side wall of the second air-fuel mixture chamber, and a second air-fuel mixture chamber formed by joining this wall material to the side of the bar body, and a wall material forming one side wall of the burner body and a wall material between the upper ends of the burner body and the wall material. Consists of a burner in which two flame ports are formed,
This burner is constructed by arranging a plurality of these burners in parallel.

Operation With the above-described configuration, gaps between the burners are eliminated, and all the secondary air flowing around the burners is introduced into the air intake port and mixed with the air-fuel mixture from the air-fuel mixture passage in the second air-fuel mixture chamber. Therefore, by supplying the unburned air-fuel mixture ejected from the second flame port to the flame formed on the first flame hole and which has a lower oxygen concentration than the atmospheric oxygen concentration, combustion can be slowed down and the flame temperature can be lowered. This results in low NOx combustion.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, 6 is a burner main body, and the upper surface of the burner main body 6 has a first flame lower having a large number of slits.

Mixture passages 8 are provided on both sides of the burner body 6 at optimal intervals in the longitudinal direction, and wall materials 10 forming a second mixture chamber 9 are attached to opposite sides of the burner body 6. ing. A second flame port 12 is formed between the upper end 11 of the wall material 1O and the burner body 6. At the bottom of the wall material 10,
Air intake ports 13 are provided at optimal intervals in the longitudinal direction of the burner body 6. 14 is a first mixture chamber. A plurality of burners 15 are arranged in parallel and in contact with each other on the side surface of the wall material 10 of the second air-fuel mixture chamber.

In the above configuration, the primary air ratio of the air-fuel mixture inside the first air-fuel mixture chamber 14 is set from 30% to 60%.

A portion of this air-fuel mixture is ejected from the first flame lower, and the remaining air-fuel mixture passes through the air-fuel mixture road 8 and is led to the second air-fuel mixture chamber 9. The secondary air flows from the bottom to the top between the burner body 6 and another burner body installed in parallel, flows into the second mixture chamber 9 through the air intake port 13, and is mixed from the mixture road 8. The mixture becomes a mixture with a primary air ratio of about 170% to 250% and below the flammability limit, and is ejected from the second flame port 12.

Here, the principle of generation of NOx generated from flame will be explained. NOx generated from flame is generally fuel NO
x and thermal NOx, and the amount of fuel NOx generated depends on the type of 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, when a flame is burned in an atmosphere with a low oxygen concentration, the reaction becomes slow and the flame reaction zone becomes large, resulting in a decrease in the amount of heat generated per unit flame reaction zone. For these reasons, the temperature of the flame reaction zone is lowered, and NOx can be reduced.

Then, all the secondary air between the burners flows into the second mixture chamber 9, diluting the mixture from the mixture road 8 (primary air ratio -30 to 60%) to below the combustibility limit. A mixture (primary air ratio = 170 to 250%) is supplied from the second flame port 12 to the flame formed on the first flame lower, and the flame backfires into the second mixture chamber 9. This is prevented. Therefore, by supplying the unburned air-fuel mixture ejected from the second flame port 12 and having a lower oxygen concentration than the oxygen concentration in the atmosphere to the flame formed on the first flame lower, the flame is formed in the burner body 6. The combustion reaction of the flame slows down and the flame temperature decreases. As a result, the generation of thermal NOx is reduced, and there is no need to provide a second combustion chamber as in conventional two-stage combustion, allowing high-load combustion.

Also, since the secondary air ports between the burners are eliminated and a thin air-fuel mixture is flowed instead of secondary air, fire transfer between the burners becomes easier.

Effects of the Invention As is clear from the description of the embodiments above, the combustion apparatus of the present invention includes a burner body having a first flame port, a mixture road, and a first mixture chamber, and a burner body having an air intake port and a first combustion chamber having an air intake port. A wall material forming one side wall of the second air-fuel mixture chamber, and this wall material is joined to the side of the burner body to form a second air-fuel mixture chamber, and a second air-fuel mixture chamber is formed between the upper end of the burner body and the wall material. It consists of a burner in which a burner port is formed, and is constructed by arranging a plurality of these burners in parallel, thereby achieving the following effects.

(II) By eliminating the gaps between each burner and guiding all the secondary air flowing between each burner to the air intake of the second mixture chamber, the mixture in the second mixture chamber can be adjusted to a primary air ratio of 1.
70 to 250% and below the combustible flammability limit, and can be combusted by supplying the unburned mixture with low oxygen concentration ejected from the second flame port to the flame formed above the first flame port. Since the reaction becomes slow and the flame temperature decreases, the generation of NOV can be reduced.

(2) By reducing the mixture in the second mixture chamber to below the combustible limit, it is possible to prevent fire from transferring to the mixture passage.

(3) Since the secondary air ports between the burners are eliminated and a thin mixture is flowed instead of the secondary air, fire transfer between the burners is facilitated.

(4) Since there is no need to provide a second combustion chamber for two-stage combustion as in the conventional case, the volume of the burner is reduced, and high-load combustion becomes possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional perspective view of a combustion device according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of the same device, and FIG. 3 is a cross-sectional view of a conventional combustion device. 6... Burner body, 7... First flame port, 8... Air mixture passage, 9... Second air mixture chamber, 10. ...Wall material, 12...Second flame opening, 13...Air intake, 14...
First mixture chamber 5 Name of agent Patent attorney Akira Koka Hari... 2 people
... -ノ＼゛ -γ $4 Goo ring-'s flame outlet δ-5L metal qi q--one shout and two IJ-ki L 10-・-4! Material lt - Second flame outlet Figure 2

Claims (1)

[Claims] A burner body having a first flame opening, a mixture passage, and a first mixture chamber; a wall material having an air intake port and forming one side wall of a second mixture chamber; The burner is joined to the side of the burner to form a second air-fuel mixture chamber, and a second flame opening is formed between the burner body and the upper end of the wall material. Combustion device.