JPS5824707A - Low nox burner - Google Patents

Abstract

PURPOSE:To lower the rate of NOX content in exhaust gas, by providing a plurality stages of metallic bodies to the passage of combustion gas being located in the rearward of the flow of a flame formed in a burner port. CONSTITUTION:Metallic bodies 10, 11, and 12, formed of wire net, made of stainless steel, molybdenum steel, iron-chromium steel, and the like, for instance, are arranged to the lower, the middle, and the upper stages in the area of high temperature in a combustion gas passage 9 where is in the rear part of a burner port 6, taking proper intervals among the stages. NOX generated by combustion is NO, in the area of high temperature immediately after a combustion flame, but NO2, that is oxidized NO, is increased in accordance with lowering of the temperature. The NO2 can be reduced to NO, however, by contacting with the metallic bodies 10-12, provided to the area of high temperature of 500 deg.C- 700 deg.C in the passage 9 of combustion gas, so that the rate of NOX contained in exhaust gas, especially the rate of NO2 contained in NOX can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a nitrogen saponified burner suitable for household combustion appliances.
The present invention relates to a reduction in NO2, and in particular, to a low NO2 burner that reduces NO2, which has a clear effect on the human body, and is also fully compatible with combustion conditions.

Conventional burners for household combustion appliances used Bunsen burners, which had the disadvantage of high NOx values. Therefore, for appliances that are used for long periods of time, such as heating appliances,
Although pre-mixed burners such as sea bank burners have reduced NO2 to the point of death compared to Bunsen burners, the proportion of N02, which has a clear effect on the human body, is higher than that of Bunsen burners, so a sufficiently low level of NO2 can be achieved. It had the disadvantage of not being Furthermore, the sea bank burner has the drawback that the flame opening has a large heat capacity and weight, so if the combustion level is reduced, the flame opening temperature decreases, resulting in a decrease in combustibility, and the TDR is extremely low.

As a means to achieve lower NOx than the sea bank burner, a wire mesh burner as shown in FIG. 2 has been proposed. In the wire mesh burner 101, the fuel ejected from the gas nozzle 102 and the primary air sucked in by its ejector effect are mixed, and surface combustion is performed in the wire mesh portion 103 as a premixed mixture. An alumina rod 104 is provided to keep the wire mesh portion 103 uniformly covered at high temperature and stabilize combustion, and a wire mesh burner 101 is provided to effectively radiate heat from the red-hot wire mesh portion 103 to the surrounding area. The outer periphery of the tube is covered with a glass tube 106. Compared to a sea bank burner, this wire mesh burner 1o1Fi has a lower heat capacity and weight at the flame opening, so the load on the flame opening can be set small, and heat radiation from the glass cylinder 105 can be effectively performed, resulting in a low flame temperature. This makes it possible to reduce NOx.

The present invention improves the wire mesh burner to further reduce NOx, and particularly reduces the proportion of NO2 in NOx.

Hereinafter, one embodiment of the present invention will be described based on FIG. 1.

FIG. 1 is a sectional view showing the principle of the low NO2 burner of the present invention. In the figure, 1 is a burner, and a primary air chamber 3. is provided opposite the gas nozzle 2. Mixing tube 4° Mixture chamber 6. Flame bottom part made of wire mesh 6. It is composed of an outer peripheral portion 7.

Reference numeral 8 denotes a combustion chamber, and metal bodies 10, 11, and 12 such as wire meshes are provided at lower, middle, and -h positions in the combustion gas passage 9 downstream thereof.

Reference numeral 13 denotes an auxiliary air introduction pipe for making up for a lack of primary air which occurs when the primary air port 3 is clogged fc, and communicates between the outside of the burner 1 and the lower part of the combustion chamber 8.

In the above configuration, the gas ejected from the gas nozzle 2 is sucked in as primary air from the air t-primary air port 3 necessary for combustion, and is guided to the mixture chamber 5 while being mixed in the mixing pipe 4. . The mixture flows from the flame port 6 made of wire mesh to the combustion chamber 8.
It is ejected uniformly and ignited at the same time, and surface combustion occurs at the flame port 6. In this case, since the flame port 6 is formed of a wire mesh, its silent fireflies are small and easily become red hot, resulting in stable combustion.

Therefore, low flame load combustion becomes 0T performance and low NOx is achieved.

Further, in the high-temperature region of the exhaust gas passage 9 downstream of the combustion chamber 8, a lower stage, a middle stage, and two stages are made of wire mesh made of stainless steel, molybdenum steel, iron-chromium steel, etc., at appropriate intervals. Metal bodies 10, 11, 12 are provided.

In the high temperature area immediately after the Hox ij flame produced by combustion, most of the NO2 is NO, but as the temperature decreases, it becomes oxidized and NO2 increases.
Wire-mesh-shaped gold-gold stripes 10, 11, 12 made of stainless steel, molybdenum steel, etc., provided in the corrosion temperature range of ~700'C
The reason why they are provided in multiple stages is to ensure that when the combustion amount of burner 1 is varied, the atmosphere of either metal body 10, 11 or 12 will be in the high temperature range of SOO to 700°C. .

Incidentally, the outer peripheral part 7 of the burner 1 can be made of a metal plate if it is expected to have a cooling effect, such as a hot air fan, but if it is a radiant type such as a stove, a material with good heat radiation efficiency such as glass should be used. .

Therefore, this all-order mixed burner uses a flame mouthpiece made of wire mesh to perform low flame mouth load combustion and effectively radiate heat from the outer periphery, compared to conventional burners. As a result, lower NOx is achieved.

Further, since a metal body is provided in the combustion gas passage to reduce 102 to NO, NO2 in the NOx component in the exhaust gas is reduced.

Furthermore, since multiple stages of metal bodies are provided, reduction from N02 to NO can always be performed efficiently even when the fuel Wlt is varied.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an embodiment of the nitrogen oxide reducing device of the present invention, and FIG. 2 is a sectional view taken along the 1E plane showing a conventional example. 6...flame port, 9...combustion gas passage,
10,11゜12...Metal body.

Claims (1)

[Claims] A nitrogen oxide reduction burner comprising a premix burner in which a permanent part is formed of a wire mesh and performs surface combustion, in which a plurality of stages of metal bodies are provided in a combustion gas passage downstream of a flame formed in the flame opening part.