JPH05180418A - Low nox burner - Google Patents

Abstract

PURPOSE:To reduce NOX and enhance the durability of a secondary air diffusion board by lowering the temperature of flames and cooling the secondary air diffusion board. CONSTITUTION:A plurality of combustion pipelines with a vent passage 2 are installed in parallel. Secondary air diffusion boards 7 are vertically installed to the upper part of a pressure reduction wall 5 installed to the side walls of the combustion pipes in order to coos the vent passages. A secondary inlet 8 is installed to the lower part diffusion boards so as to supply a small amount of secondary air while an upper part secondary air inlet 9 is installed to the upper part so as to supply a large amount of secondary air where a water pipeline 10 is installed so as to penetrate the secondary air diffusion boards 7. The secondary air supplied from the lower part secondary air inlet is small in its quantity and serves to stabilize the flames and inhibit a rise in the flame temperature. The secondary air supplied from the upper part secondary air inlet shortens the flames, promotes the combustion and leaves a high temperature region fast, thereby reducing NOx. In addition, a water pipe is installed so as to penetrate the secondary air diffusion boards 7 and absorb the heat, which makes it possible to lower the flame temperature, cool the secondary air diffusion board and enhance the durability.

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to low NO _X combustion apparatus measure the reduction of NO _X.

[0002]

2. Description of the Related Art Conventionally, in a combustion apparatus in which a plurality of combustion tubes are arranged in parallel, secondary air is positively distributed and supplied toward a flame from a passage between the combustion tubes to react with the secondary air. There is one that is improved to improve the combustion state (see, for example, Japanese Utility Model Laid-Open No. 62-148827).

However, in this type of combustion apparatus, the passage speed of the combustion gas in the high temperature region is not so much improved, and N
There is room for improvement with respect to the generation of O _X , and the applicant has previously provided a decompression wall in which the lower end is fixed to the side wall of the combustion pipe and the upper end is erected above the flame hole of the combustion pipe. It proposed a low NO _X combustion device to form a throttle portion projecting the upper flame hole side with opening the vent on the side surface of the (Japanese Patent Application No. 2-2208
No. 20).

As a result, the reaction with the secondary air is improved to improve the combustibility, and at the same time, the passage speed of the combustion gas can be increased by the throttle portion so as to leave the high temperature region quickly, and NO _X is generated. Could be reduced.

[0005]

However, this low NO
_{In the X-} combustion system, the secondary air flow is changed by the pressure reducing wall on the downstream side of the flame hole surface to distribute and supply to improve the combustibility, so the temperature of the pressure reducing wall rises too much and is deformed. It was easy and there was a problem with durability.

It is an object of the present invention to provide a low NO _x combustion apparatus which solves the above problems by lowering the flame temperature and cooling the secondary air diffusion plate forming the pressure reducing wall.

[0007]

In order to achieve the above-mentioned object, the present invention has a plurality of combustion pipes arranged side by side with a ventilation passage, and a decompression wall for forming a supplementary flame on the side wall of the combustion pipes. A secondary air diffusion plate is erected above the decompression wall so as to close the air passage, and a lower secondary air port for supplying a small amount of secondary air is provided below the secondary air diffusion plate. An upper secondary air port for supplying a large amount of secondary air is provided above, and a water pipe is provided through the secondary air diffusion plate.

[0008]

[Function] A small amount of secondary air is supplied from the lower secondary air port toward the flame formed in the flame hole to stabilize the flame, and the secondary air does not supply sufficient air for the reaction. Does not rise too much. Then, combustion is promoted by the secondary air from the upper secondary air port, the passage speed of the combustion gas in the high temperature region of the flame is increased, and NO
Reduce the generation of _X. Further, the heat of the secondary air diffusion plate is absorbed by the water pipe, the flame temperature is lowered, and the durability is improved by cooling the secondary air diffusion plate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of the essential parts showing an embodiment of the present invention.
FIG. 2 is a perspective view of a main part.

Reference numeral 1 denotes a combustion tube, and a plurality of air passages 2 are provided in parallel to form a combustion device. Reference numeral 3 is a flame hole provided on the upper surface of the combustion tube 1, and 4 is a flame-repair hole provided on the side surface of the combustion tube 1. Reference numeral 5 denotes a pressure reducing wall having a lower end fixed to the side wall of the combustion tube 1 and provided with a gap 6, which forms a supplementary flame in the gap 6. Reference numeral 7 denotes a secondary air diffusion plate which is erected above the pressure reducing wall 5.
The lower secondary air port 8 for supplying a small amount of secondary air to the flame surface on the lower side and the upper secondary air port 9 for supplying a large amount of secondary air on the upper side. There is. Reference numeral 10 denotes a water pipe penetrating the secondary air diffusion plate 7 to absorb heat of the secondary air diffusion plate 7.

In this combustion apparatus, a small amount of secondary air is supplied from the lower secondary air port 8 below the secondary air diffusion plate 7 to stabilize the flame in the flame hole 3, but sufficient air for combustion is not generated. Since it is not supplied, the flame temperature does not rise so much, the combustion gas rises in an incomplete combustion state, the combustion is completed by the secondary air from the upper secondary air port 9 above, and the combustion gas is in the high temperature region. Leave early. Then, the heat of the secondary air diffusion plate 7 is absorbed by the water pipe 10, and the flame temperature is lowered by absorbing the heat of the flame, so that the combustibility is good and the flame can be shortened and NO _X can be reduced. The next air diffusion plate 7 is cooled and the durability can be improved.

The decompression wall 5 and the secondary air diffusion plate 7 may be integrally formed so that the lower secondary air port 8 below is provided at the flame hole surface position.

Further, as shown in FIG. 3, a throttle portion 11 is formed by bending the upper portion of the secondary air diffusion plate 7 toward the flame hole 3 side so as to project, and an upper secondary air port is formed on the side surface of the throttle portion 11. 9 may be provided to promote the contact between the secondary air and the flame to further improve the combustibility, and the throttling action of the throttling portion 11 further accelerates the flow velocity to leave the high temperature region earlier. Therefore, the generation of NO _X can be further reduced.

[0014]

As described above, the present invention supplies a small amount of secondary air below the secondary air diffusion plate and a large amount of secondary air above.
Since the secondary air diffuser has a water pipe penetrating the secondary air port, a small amount of secondary air supplied from the lower secondary air port stabilizes the flame and the secondary air is sufficient for reaction. Is not supplied, it does not raise the flame temperature so much. Then, the secondary air from the upper secondary air port shortens the flame to promote combustion, and quickly separates the combustion gas from the high temperature region of the flame. Therefore, the generation of NO _X can be reduced, and the heat of the secondary air diffuser plate can be absorbed by the water pipe to lower the flame temperature and improve the durability of the secondary air diffuser plate.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a main part of the same example.

FIG. 3 is a cross-sectional view of essential parts showing another embodiment of the secondary air diffusion plate.

[Explanation of symbols]

 1 Combustion pipe 2 Ventilation path 3 Flame hole 7 Secondary air diffuser plate 8 Lower secondary air port 9 Upper secondary air port 10 Water pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Ueda 32 Akashi-cho, Chuo-ku, Kobe-shi, Hyogo Noritsu Co., Ltd.

Claims (1)

[Claims] 1. A plurality of combustion pipes are provided side by side with an air passage,
A pressure reducing wall for forming a flame-repair is provided on the side wall of the combustion tube, and a secondary air diffusion plate is erected above the pressure reduction wall so as to close the air passage, and a small amount is provided below the secondary air diffusion plate. Is provided with a lower secondary air port for supplying secondary air, and an upper secondary air port for supplying a large amount of secondary air is provided above, and a water pipe is provided through the secondary air diffusion plate. Low NO _x combustion device.