JPS63210507A - Burner - Google Patents

Abstract

PURPOSE:To reduce the amount of NOx and expand the variable range of turn down ratio (TDR), by a method wherein a combustion chamber is formed so that combustion chamber walls, provided with a plurality of flame ports, are opposed to form opposed flames between the combustion chamber walls mutually while the flame ports are arranged locally and crowdedly so as to form a plurality of groups. CONSTITUTION:When liquid fuel is used, a sheath heater 11 is energized and the fuel is injected through a nozzle 13. The liquid fuel 16 collides against an evaporating tube 10 to evaporate, mixes with air sent simultaneously together with the fuel, and thereafter passes a throat to become a uniform mixture 18. Then, the mixture 18 is supplied through a mixing chamber 7 into a combustion chamber 5 through flame ports 6 and ignited by an ignitor 14, whereby opposing flames 19 are formed. After effecting premixed combustion, exhaust gas 20 is discharged. The opposing flames 19, formed in such a manner, form points of stagnation at the parts whereat the flames are collided and the flow speed of the exhaust gas is reduced, whereby the flames are stabilized. The flame ports 6 are arranged so as to form a plurality of groups 6A on the combustion chamber walls 2' therefore, the flames are dispersed remarkably and the temperature of the flames is reduced, whereby low NOx combustion may be promoted and the variable range of turn down ratio (TDR) may be expanded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an indoor open type combustor.

Conventional technology Conventionally, many burners for indoor open type combustors such as fan heaters have adopted a partial premix combustion method, which has the advantage of having a wide variable range of combustion amount (hereinafter referred to as TDR). there were. In this case, fuel and air are ignited in a partially mixed state, and a diffusion flame is formed downstream of the premixed flame to achieve complete combustion.

Problems to be Solved by the Invention However, in such a partial molecular mixture combustion method, the flame temperature is high, and furthermore, due to the diffusion combustion, the combustion time is long, and nitrogen oxides (hereinafter referred to as No. ) was a problem in that the amount of emissions was large. High concentrations of No are said to have an adverse effect on the human body, so a fully premixed twisting and laying method was adopted to reduce NOx.
The TDR was narrow, making it disadvantageous as a combustor. If a wire mesh is used in a small combustion area, the jet flow velocity is reduced and the heat of the flame is dissipated into the wire mesh, resulting in a low No.
However, the problem is that the wire mesh tends to deform due to heat. The present invention has low NOx and TD
This provides a burner with a wide radius.

Means for Solving the Problems The present invention solves the above problems by forming a combustion chamber by arranging at least one pair of combustion chamber walls having a plurality of flame holes at a fixed distance from each other and facing each other. The flame holes are also coaxially opposed to each other between the combustion chamber walls to form opposing flames, and the flame holes are arranged in a locally dense manner so as to form a plurality of groups on the combustion chamber wall. ing.

Effect: With the above configuration, opposed premixed flames are formed in the combustion chamber, so the flow velocity becomes small at the flame collision part in the combustion chamber, and the flame can be stabilized. At this time, it is possible to achieve low NOx because the air ratio is increased and good combustion can be achieved even at low flame temperatures. In addition, compared to the case where a wire mesh is used in the combustion part, the jet flow is sharper and the flames collide more easily, so the heat of the flame is radiated to the combustion chamber wall, the flame temperature decreases, the flame area becomes larger, and the flame area becomes larger. , low No. process is promoted. moreover,
Since the flame holes are arranged in a plurality of groups, the flame is significantly dispersed, the flame temperature is lowered, and NOx can be reduced. On the other hand, when the combustion amount is reduced, the flame holes become denser and the load is locally increased, so the effect of the opposing flames also fades, making it possible to achieve stable combustion.
This is also effective in expanding DR.

EXAMPLE A specific explanation will be given below using the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the burner, and FIG. 3 is a sectional view taken along line A-A in FIG. The main parts of the burner are the outer wall 1. Combustion chamber wall 2. It is composed of side plates 3, two combustion chamber walls 2 are provided facing each other, and the side plates 3 and the bottom plate 4 form a combustion chamber 6. 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 also located at opposing positions. As shown in FIG. 3, the flame holes 6 are arranged in a locally dense manner so as to form a plurality of groups 6A on the combustion chamber wall 2. A mixing chamber 7 is formed by the combustion chamber wall 2 and the outer wall 1, and a throat 8. Vaporization chamber9. There is a vaporizer cylinder 1°, and the vaporizer cylinder 1o is
A sheathed heater 11 is installed. Further, an air passage 12 is communicated with the vaporization cylinder 10, and a fuel injection nozzle 13 is provided inside. Furthermore, the combustion chamber 5 includes an igniter 1.
4 and a combustion detector 15 are provided.

Next, the operation will be explained. First, when using liquid fuel, energize the sheathed heater 11 and
gush out. The liquid fuel 1θ collides with the vaporization cylinder 1o and is vaporized, and after being mixed with the air 17 sent at the same time, it passes through the throat 8 and becomes a uniform air-fuel mixture 18. After that, it passes through the mixing chamber 7, is supplied to the combustion chamber 5 from the flame hole 6, and is supplied to the igniter 14.
is ignited to form an opposing flame 19. After performing premix combustion, it becomes exhaust gas 20 and is discharged.

On the other hand, when gaseous fuel is used, the vaporization cylinder 10 is not required, and the downstream side of the throat 8 can be used with the same configuration as when using liquid fuel.

The opposing flames 19 thus formed form a stagnation point at the flame collision part in the combustion chamber 5, the flow velocity becomes small, and the flame can be stabilized. Therefore, it is possible to increase the air ratio and achieve good combustion even at low flame temperatures, resulting in a low No.
Industrialization becomes possible.

In addition, compared to the case where a wire mesh is used in the combustion part, the jet flow velocity is higher and the flames collide more easily, so the heat of the flame is radiated to the combustion chamber wall 2, the flame temperature decreases, and the flame area becomes narrower. NOx can be effectively reduced.

Furthermore, since the flame holes 6 are arranged in a plurality of groups 6A on the combustion chamber wall 2, the flame is significantly dispersed, the flame temperature is lowered, and NOx reduction can be further promoted. On the other hand, even when the combustion amount is reduced, stable combustion is not only achieved by the opposed flames 19, but also by locally crowding the flame holes 6 to increase the load. , it is also possible to track the TDR.

Further, since the flame holes 6 are arranged in a plurality of groups 6A on the combustion chamber wall 2, the exhaust gas 20 is discharged from between the groups of flame holes 6, as shown in FIG. . By forming a part of the exhaust gas passage in the combustion chamber 6 in this way,
By applying the heat of the exhaust gas 20 to the combustion chamber wall 2 without the flame being affected by the components of the exhaust gas 20, the flame can be stabilized and the blow-off limit can be extended. Also,
Since the combustion chamber wall 2 is made of a plate, it does not undergo thermal deformation unlike wire mesh, and has a long service life as shown in Fig. 9. Furthermore, it is easy to process, making it easy to achieve low costs. .

By forming the combustion chamber wall 2 with a heat-resistant material such as ceramic, it can be used even under high load conditions, and by reducing the diameter of the flame hole 6 to less than the extinguishing distance, it is effective in preventing backfire. .

Effects of the Invention As explained above, according to the burner of the present invention, the following effects can be obtained. The opposing flames stabilize the flame, allowing combustion in areas with a large air ratio.
It becomes possible to achieve low N○ engineering. However, by flame collision, the heat of the flame is radiated to the combustion chamber wall, and the flame area is narrowed, effectively achieving low No. By doing so, the flame dispersion becomes more pronounced, the flame temperature is lowered, and the image N
Oxification can be promoted. On the other hand, even when the combustion amount is reduced, not only is it stabilized by the opposing flames, but the flame holes are locally densely packed to achieve a high load and stable combustion is achieved, resulting in TDR. It is also possible to make it larger. In addition, since the combustion chamber wall is made of a plate, it is not subject to thermal deformation unlike wire mesh, and has a long lifespan.Furthermore, it is easy to process, making it easy to reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a burner according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the burner, and Fig. 3 is a sectional view taken along line AA in Fig. 2. 2... Combustion chamber wall, 6... Combustion chamber, 6...
...flame hole, 7...mixing chamber, 10...
Vaporizer cylinder, 14...Igniter, 6A...Multiple groups. Name of agent: Patent attorney Toshio Nakao and one other person? −
To the person, the wall of Kyoto --- 32 pieces Figure 1 lθ-vaporization recitation?

Claims (1)

[Claims] At least one pair of combustion chamber walls having a plurality of flame holes are arranged to face each other at a certain distance to form a combustion chamber, and each flame hole is configured to coaxially face each other between the opposing combustion chamber walls, A burner characterized in that flame holes are locally arranged densely in a plurality of groups on the combustion chamber wall, and a mixing chamber is provided between the combustion chamber wall and an outer wall.