JPS5824708A - Low nox burner - Google Patents

Abstract

PURPOSE:To lower the rate of NOX, by providing metallic bodies such as wire net, to the inside of a burner port and the outlet of combustion gas, respectively, in the titled burner which is adequate to a combustion appliance for home use. CONSTITUTION:The secondary metallic body 11 is provided to the neighborhood of an outlet 10 for combustion gas, in the upper part of a combustion chamber 8, as well as to provide a metallic body 9, formed of wire net and the like, made of stainless steel, for instance, to the neighborhood of a burner port 6 in a combustion chamber 8. With such an arrangement, heat capacity is small at a burner port 6, and red-heated, stable combustion can easily be obtained. Accordingly, low loaded combustion can be taken place at the burner port and the rate of NOX contained in exhaust gas can be lowered. At the same time, atmosphere around the metallic body 9 is turned to a reducing atmosphere, so that generated NOX is reduced to lower the rate of NOX further, by contacting with the metallic body 9 which is served as a reducing catalyst. Besides, the secondary metallic body 11, which is located in a position where the temperature of exhaust gas rises up to 500-700 deg.C, is served as a reducing catalyst, which can reduce NO2 to NO.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the reduction of nitrogen oxides (NOx) in burners suitable for household combustion appliances, and in particular, an invention that can also reduce nitrogen oxides (NOx), which have a clear effect on the human body. It concerns Kuna.

Conventional burners for household combustion appliances used Bunsen burners, which had the disadvantage of high 1iOx values. Therefore, for appliances that are used for a long time, such as heating appliances,
Many of them used premix burners such as Schwank burners to reduce NOx.

However, although the NOx value of the Schwank burner is as low as a crane compared to the Bunsen burner, the proportion of NO2, which has been shown to have an effect on the human body, is higher than that of the Bunsen burner, so it is not enough to reduce the NOx value. It had the drawback that N02 was not achieved.

Furthermore, because the heat capacity of the ceramic plate that forms the flame nozzle is large, Schwank burners have the disadvantage that it takes a long time to reach stable combustion upon ignition. It has the disadvantage that TDR is difficult to obtain because the temperature decreases and combustibility deteriorates.

A wire mesh burner as shown in FIG. 2 has been proposed as a means for achieving low NOx in the Schwunk burner.

The wire mesh burner 101 mixes the fuel ejected from the gas nozzle 1o2 with the primary air sucked in by its ejector effect.
Combustion is performed on the surface of the wire mesh section 103 as a premixture. In order to maintain the temperature of the wire mesh portion 103 at a constant high temperature and obtain stable combustion, an alumina rod 104 is provided inside the wire mesh portion 103, and to effectively radiate heat from the red-hot wire mesh portion 103 to the same side. In order to do this, the outer periphery of the wire mesh burner 101 is covered with a glass cylinder 105. This wire mesh burner 1o1 has a smaller heat capacity at the flame opening compared to the Schbank burner, so the load on the flame opening can be reduced, and heat radiation from the glass cylinder 106 can be effectively performed, resulting in a low flame temperature. This can reduce NOx.

The present invention improves the wire mesh burner to further reduce NOx, and particularly reduces the proportion of No 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 nitrogen oxide reducing burner of the present invention.

In the figure, reference numeral 1 indicates a burner, and a mixing tube suction port 3. Mixing tube4. Mixture chamber6. 6. Flare port made of wire mesh. Combustion tube7. It consists of a combustion chamber 8. A metal body 9 made of the same cylindrical wire mesh or the like is provided near the flame port 6 in the combustion chamber 8. Further, a second metal body 11 is provided near the combustion gas outlet section 10. Reference numeral 12- denotes an auxiliary air introduction pipe for supplementing the primary air shortage that occurs when the air port 3 is clogged, and is connected 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
Air necessary for combustion is sucked in as primary air through a single air port 3, and guided to a mixture chamber 5 while being mixed in a mixing tube 4. The air-fuel mixture is uniformly injected into the combustion chamber 8 from the flame port 6 made of wire gauze and ignited at the same time, and surface combustion occurs in the flame port 6. In this case, since the flame port 6 is formed of a wire mesh, its heat capacity is small and it easily becomes red hot to obtain stable combustion. Therefore, low flame port load combustion is possible, and low NOx can be achieved.

Furthermore, a metal body 9 formed of a wire mesh or the like made of stainless steel, molybdenum-2-iron-chromium steel, etc. is provided at the flame port 6 in the combustion chamber 8. That is, the tip of the flame is the metal body 9.
Since the metal body 9 is provided in a position in contact with the
Oxification can be achieved.

Further, the second metal body 11 provided near the combustion gas outlet 1o at the upper part of the first combustion chamber 8 has an exhaust gas temperature of SOO to 70.
0''C, the metal body 11 acts as a reduction catalyst, and the NO□ component is reduced to NO.

Incidentally, since the metal body 11 is provided near the flame nozzle 6, the flame nozzle 6 can be easily maintained at a high enough temperature to obtain stable combustion.

Furthermore, the combustion tube 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, it is recommended to use a material with a good heat radiation rate such as glass. Become.

Therefore, the all-primary mixed burner, which has a flame opening made of wire mesh, performs low flame opening load combustion and effectively radiates heat from the outside of the burner, compared to conventional burners. A low How low sky has been achieved.

Furthermore, a metal body is installed in the reducing device near the flame opening, and the N
Since Ox is reduced, NOx can be further reduced, and since a metal body is provided in the high temperature atmosphere of the combustion gas passage, NO2 in the combustion gas is reduced to No, which reduces the impact on the human body. Obvious NO2 is reduced.

The case where the metal bodies are arranged side by side has been described above, but it is clear that effects corresponding to each one can be obtained even when one of them is provided.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing one embodiment of the nitrogen oxide reducing burner of the present invention, and FIG. 2 is a front sectional view showing a conventional example. 6... Flame hole part, 7... Combustion tube, 8...
... Combustion chamber, 9.11 ... Metal body, 10.
... Combustion gas outlet section.

Claims (1)

[Claims] In a premix burner in which a flame hole is formed with a wire mesh inside a cylindrical combustion tube and performs surface combustion, both the combustion chamber inside the flame hole and the combustion gas outlet at the upper part of the combustion chamber, or A nitrogen oxide reduction burner that has a metal body such as a wire mesh on either side.