JPH081281B2 - Burner - Google Patents

Description

TECHNICAL FIELD The present invention relates to an indoor open type combustor.

2. Description of the Related Art Conventionally, burners for indoor open combustors such as fan heaters often employ a partial premixed combustion method, which has the advantage that the combustion amount variable range (hereinafter referred to as TDR) is wide. It was In this case, the fuel and the air are partially mixed and ignited to form a diffusion flame on the downstream side of the premixed flame to complete combustion.

The problem to be solved by the invention is that such a partial premixed combustion system has a high flame temperature and, in addition, since diffusion combustion is performed, the combustion time is long and nitrogen oxides (hereinafter referred to as NO _x ) There was a problem that the amount of emissions was large. When NO _x is in a high concentration is said to adversely affect the human body, Therefore, utilizes a fully premixed combustion method, but low NO _x reduction is achieved, TDR is narrow, unfavorable as combustor It was a thing. The present invention is low NO
_It provides a burner with wide _x and TDR.

Means for Solving the Problems In order to solve the above problems, the present invention makes a combustion chamber wall having a plurality of flame holes face each other at a constant distance and forms a complete combustion chamber by the combustion chamber wall, side plates and bottom plate. Premixed combustion is performed to form an opposing flame. Further, the combustion chamber wall is provided with column-shaped projections protruding toward the combustion chamber side to divide the combustion chamber.

Action With the above configuration, the opposed premixed flame is formed in the combustion chamber, so the flow velocity is reduced in the central portion of the combustion chamber, and the flame can be stabilized. At this time, since good combustion can be realized even in a state where the air ratio is high and the flame temperature is low, it is possible to reduce NO _x . Further, melt the rows of projections on the combustion chamber wall, the flame of heat radiated to the projection, further, because of the remarkable dispersibility of the flame, lowered the flame temperature, even, contributing to the low NO _x reduction it can. On the other hand, when the amount of combustion is reduced, the row-shaped protrusions form the combustion gas discharge path in the combustion chamber, suppressing the interference between flames and preventing the inflow of air into the vicinity of the flames. It is also effective in increasing TDR and expanding TDR. Particularly, when the height of the protrusions is 2 mm or more, the flame holding effect is improved. Also, by forming the combustion chamber wall with a heat-resistant material, the life can be extended even under high load conditions, and the diameter of the flame hole can be reduced.
By making it as small as 2 mm or less, it is also effective in preventing flashback.

Example Hereinafter, a specific description will be given with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view of the burner. The main part of the burner is the outer wall 1, the combustion chamber wall 2,
The side wall 3 is formed by the side plate 3, the two combustion chamber walls 2 are provided so as to face each other, and the side plate 3 and the bottom plate 4 form a combustion chamber 5. Further, the combustion chamber wall 2 is provided with a plurality of flame holes 6, and, like the combustion chamber wall 2, the flame holes 6 are at positions facing each other. Further, the combustion chamber wall 2 is provided with a column-shaped projection 7 so as to project toward the combustion chamber 5 side,
The combustion chamber 5 is divided. Combustion chamber wall 2
A mixing chamber 8 is formed by the outer wall 1 and the outer wall 1. A throat 9, a vaporization chamber 10, and a vaporization cylinder 11 are provided on the upstream side of the mixing chamber 8.
A sheathed heater 12 is installed at 1. Also, vaporization cylinder 1
An air passage 13 is communicated with 1 and a fuel injection nozzle 14 is provided inside. Further, the combustion chamber 5 includes an igniter 15
And a combustion detector 16 are provided.

Next, the operation will be described. First, when liquid fuel is used, the sheath heater 12 is energized to heat the vaporization cylinder 11, and then the liquid fuel 17 is ejected from the fuel ejection nozzle 14. The liquid fuel 17 collides with the vaporization cylinder 11, is vaporized, and is mixed with the air 18 sent at the same time, and then passes through the throat 9 to become a uniform air-fuel mixture 19. Then, it passes through the mixing chamber 8 and is supplied to the combustion chamber 5 through the flame holes 6 and is ignited by the igniter 15 to form the opposing flame 20. Then, after the premixed combustion is performed, the exhaust gas 21 is discharged.

On the other hand, when using the gaseous fuel, the vaporization cylinder 11 is not necessary, and the same configuration as when using the liquid fuel can be used on the downstream side of the throat 9.

In this way, the opposing flame 20 formed forms a stagnation point in the flame collision portion of the combustion chamber 5, and the flow velocity becomes small,
The flame can be stabilized. Further, the static pressure increases as the flow velocity decreases toward the stagnation point, and the flow velocity of the opposing flame 20 becomes uniform, so that the combustion state becomes uniform. Further, since the opposing flame 20 is formed, stable combustion can be performed even in a region where the air ratio is large, so that NO _x can be reduced. Further, even if the combustion amount is made small, good combustion can be performed, so that the TDR can be increased. Furthermore, the columnar projections 7 are provided on the combustion chamber wall 2 to radiate the heat of the flame to the projections 7 and further to make the dispersion of the flame remarkable, thereby suppressing the rise of the flame temperature, Even lower NO _x
Can be promoted.

On the other hand, when the combustion amount is reduced, the row-shaped projections 7
Forms a combustion gas discharge path in the combustion chamber 5 to suppress interference between flames and prevent air from flowing into the vicinity of the flames.
It is also effective in enhancing the flame holding effect and expanding the TDR. The combustion chamber wall 2 forming the combustion chamber 5 is made of a plate and also has the protrusions 7, so that it does not undergo thermal deformation like a wire mesh, and is easy to process and easy to reduce the cost. . Further, by forming the combustion chamber wall 2 with a heat resistant material such as ceramics, the life can be extended even under a high load condition, and by reducing the diameter of the flame hole 6 to be less than or equal to the extinction distance, it is possible to prevent flashback. Become effective. Further, when the height of the protrusions 7 is set to 2 mm or more, the flame holding effect is improved and the amount of heat radiation is increased, which is also effective for lowering NO _x .

Effects of the Invention As described above, according to the burner of the present invention, the following effects can be obtained. A stagnation point is formed by the opposing flame, the flame is stabilized, and combustion is performed in a region with a large air ratio, so that it is possible to achieve low NO _x . Next, even if the combustion amount is reduced, good combustion can be performed, so that the TDR can be increased.
Further, since the flow velocity becomes smaller and the static pressure becomes larger in the combustion chamber, the flame becomes uniform throughout, a uniform combustion state can be secured, and the temperature distribution becomes uniform. Furthermore, the row-shaped protrusions remove the heat of the flame and lower the flame temperature to further promote the reduction of NO _x , and even when the combustion amount is small, a combustion gas discharge path is formed in the combustion chamber. By suppressing the interference between flames and preventing the inflow of air near the flames,
It is possible to enhance the flame holding effect and expand the TDR.

[Brief description of drawings]

FIG. 1 is a perspective view of a burner according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the burner. 2 ... Combustion chamber wall, 5 ... Combustion chamber, 6 ... Flame hole, 7 ... Projection, 8 ... Mixing chamber, 11 ... Vaporizing cylinder, 15 ... Ignition device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sachio Nagamitsu 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masaru Ito 1006 Kadoma, Kadoma, Osaka Matsushita Electric Industrial Co., Ltd. In-house (72) Inventor Kenkichi Hashido 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References Japanese Unexamined Patent Publication No. 52-23735 (JP, A) No. 56-39851 (JP, Y2)

Claims (1)

[Claims] 1. A combustion chamber wall having a plurality of flame holes facing each other at least one pair at a constant distance to form a combustion chamber by the combustion chamber wall, a side plate and a bottom plate, and each of the facing combustion chamber walls is opposed to each other. The flame holes are coaxially opposed to each other, and the combustion chamber wall is provided with a column-shaped projection protruding toward the combustion chamber side so as to divide the combustion chamber. A burner characterized by having a mixing chamber between them.