JPH0216101Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] This invention relates to a surface combustion burner using a permeable block.

[Prior Art] An example of a conventional surface combustion burner is shown in FIG. This is a premixing system in which a mixing chamber 4 is separated by a partition wall member 3 on the back side of a flame stabilizing plate 1 formed of a permeable block, and a mixed gas 15 of fuel gas and combustion air is supplied to the mixing chamber. It is a method. Conventional premix type surface combustion burners have the following problems.

(1) Although it can prevent the generation of carbon monoxide and has good combustibility, it cannot suppress the generation of NOx, which causes photochemical smog. This is because countless fine flames are formed on the surface of the permeable block, and these flames heat each other, raising the combustion temperature.

(2) Also, there is a high risk of backfire. This is a drawback of premix burners, but since the area immediately downstream of the permeable block is filled with the mixed gas for combustion, in the event that the flame flows backwards, the mixed gas ignites and backfires. If there is a backfire, there is a risk not only of burner damage but also of a major accident.

[Purpose of the invention] This invention focuses on the problems mentioned above, and uses a two-stage combustion method to suppress the generation of NOx, reduce the risk of flashback, and increase the suction effect of combustion gas. The present invention provides a surface combustion burner with improved combustion performance.

[Summary of the invention] That is, this invention includes a flame holding plate 1 formed of a transparent block and an air register 2 provided so as to cover the flame holding plate 1, and a partition wall member 3 provided on the back side of the flame holding plate. In a gas burner structure in which a mixing chamber 4 is separated and an open end 6 of a fuel gas supply pipe 5 is connected facing the mixing chamber, the air is disposed around the open end 6 of the fuel gas supply pipe. In order to form a gap 7 for introducing air into the register,
The cylindrical member 11 is arranged concentrically, and the tip of the cylindrical member is provided to protrude from the open end 6,
It is characterized in that an annular secondary air flow path is formed between the peripheral wall portion 8 of the air register and the side portion 9 of the partition member.

[Example] Hereinafter, an example of this invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of this invention, in which a mixing chamber 4 is separated by a flame-holding plate 1 formed of a permeable block and a partition member 3. The open end 6 of the gas supply pipe 5 is connected thereto. Further, a cylindrical member 11 is inserted around the open end 6 of the fuel gas supply pipe to form a gap 7, and the cylindrical member is arranged concentrically with the fuel gas supply pipe 5, The tip of the cylindrical member is provided to protrude from the open end 6. An air register 2 is provided over the above-described structure, and an annular secondary air flow path is formed between the peripheral wall portion 8 of the air register and the side surface portion 9 of the partition member.

FIG. 2 is a sectional view of another embodiment of this invention, in which the tip of the annular secondary air flow path described above is covered with a mesh member 16 such as a punching plate. This mesh member has a small diameter portion in contact with the side surface portion 9 of the partition wall member, and a large diameter portion in contact with the peripheral wall portion 8 of the air register.
It has an approximately truncated cone shape.

Next, the operation of this invention will be explained. Fuel gas 10 is supplied into mixing chamber 4 through fuel gas supply pipe 5 . On the other hand, after the combustion air 12 is sent into the air register 2, part of it passes through the gap 7 as secondary air 13 and the rest as primary air 14, and then is supplied into the mixing chamber. The primary air is close to or less than the theoretical air amount, and the mixed gas of the fuel gas 10 and the primary air 14 mixed at a high speed in the mixing chamber 4 passes through the flame holding plate 1, and then
A flame is formed on the surface, primary combustion is performed, and then the above-mentioned secondary air 13 is supplied to the flame,
Allow complete combustion.

Moreover, when mixing the fuel gas and primary air, the cylindrical member 11 is arranged approximately concentrically with the fuel gas supply pipe 5, and the tip of the cylindrical member is made to protrude beyond the open end 6 of the fuel gas supply pipe. Due to the configuration,
Not only can the effect of primary air sucking fuel gas be enhanced, but also the primary air and fuel gas can be effectively mixed at the outlet section with the above configuration, and the permeable block can be removed in this state (primary mixed state). 1, a combustion flame can be formed on the surface, and the combustibility on the surface can be greatly improved.

[Effects of the invention] (1) The surface combustion burner of this invention separates the combustion air into primary air and secondary air, causes excessive combustion of fuel by the primary air, and removes unburned fuel by the secondary air. completely burn out. Since the so-called two-stage combustion method is used, the generation of NOx can be suppressed. This is because the combustion temperature can be lowered by the secondary air, and combustion can be performed at a low oxygen concentration in the primary combustion.

(2) In addition, since the primary air amount is close to and below the theoretical air amount, the mixed gas in the mixing chamber 4 is in a state of excess fuel, and there is a risk of backfire compared to the complete premixing method. Sexuality decreases.

(3) Since the secondary air 13 is rectified by the mesh member 16 and then uniformly supplied to the flame, it is possible to prevent the flame from drifting.

(4) The cylindrical member 11 is inserted concentrically around the open end 6 of the fuel gas supply pipe, and the tip of the cylindrical member 11 is provided so as to protrude from the open end 6. 10 and primary air 14
can be efficiently mixed while sucking the fuel gas with primary air.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the surface combustion burner according to this invention, and FIG. 2 is a longitudinal sectional view showing another embodiment of the surface combustion burner according to this invention.
FIG. 3 is a longitudinal sectional view showing an embodiment of a conventional surface combustion burner. 1...Flame holding plate, 2...Air register, 3...
Partition member, 4... Mixing chamber, 5... Fuel gas supply pipe, 6... Open end, 7... Gap, 8... Peripheral wall portion, 9... Side portion of partition member, 11... Cylindrical member , 16...Mesh member.

Claims (1)

[Claims for Utility Model Registration] A flame-holding plate 1 made of a transparent block and an air register 2 provided over the flame-holding plate 1 are provided, and a mixing chamber 4 is defined by a partition member 3 on the back side of the flame-holding plate. In the configuration of the gas burner in which the open end 6 of the fuel gas supply pipe 5 is connected to the mixing chamber so as to face the mixing chamber, the air in the air register is connected to the open end 6 of the fuel gas supply pipe 5. In order to form the introduction gap 7, a cylindrical member 11 is arranged concentrically, and the tip of the cylindrical member is provided to protrude from the open end 6, and the peripheral wall portion 8 of the air register and the partition wall are provided. A surface combustion burner characterized in that an annular secondary air flow passage is formed between the side part 9 of the member.