JPS63187015A - Burner - Google Patents

Abstract

PURPOSE:To stabilize flames and make combustion possible in the range of a large air ratio with opposing flames and to select a TDR (variable range in the amount of combustion) widely even when the amount of combustion is made small by a method wherein flame holes are so constituted as to oppose each other on the same axis. CONSTITUTION:The walls 2 of a combustion chamber are composed of two plates opposing each other and form the combustion chamber 5 with side plate 3 and a bottom plate 4. On the walls 2 a plurality of flame holes 6 are installed in such a condition as to be thin at the central part and dense at the circumferential part and the holes 6 are in the location to oppose each other just in the same way as the walls 2. A mixing chamber 7 is formed with the walls 2 and external walls 1. Because a plurality of the holes 6 are installed on the walls 2, the ejecting flow velocity of flames 19 is large and the flames 19 collide with each other to radiate heat to the walls 2 and a flame area is expanded to reduce flame temp. and made to promote the generation of low NOx further. On the other hand, even when the amount of combustion is made small, heat loss is small and stable combustion is therefore able to be carried out and a device is useful in case when a TDR is 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 premix combustion method, the flame temperature is high, the combustion time is long because diffusion combustion cannot be performed, and the emission of nitrogen products (hereinafter referred to as NOx) is high. There was a problem that the amount was large. High concentrations of NOx are said to have an adverse effect on the human body.For this reason, a completely premixed combustion method was adopted to reduce NOx, but carbon oxide (hereinafter referred to as COx), etc. This was easy to occur and the TDR was narrow, making it disadvantageous as a combustor.

Generally, when using a wire mesh on the combustion chamber wall, it is possible to reduce N by reducing the flow velocity and radiating the heat of the flame to the wire mesh.
Although attempts were made to use oxygen, there was a problem in that the wire mesh was easily deformed by heat and deteriorated easily. Furthermore, although the properties of Co are good in those using wire mesh, there is a problem in that the TDR is narrow.

The present invention provides a burner with low NOx and wide TDR.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention forms a combustion chamber by arranging at least one pair of combustion chamber walls having a plurality of flame holes to face each other at a certain distance. They are configured so that they face each other on the same axis, and the flame holes provided in the combustion chamber walls are arranged sparsely in the center and densely in the periphery to achieve complete premixed combustion and form opposing flames. .

Effect: With the above configuration, since opposing premixed flames are formed in the combustion chamber, the flow velocity is reduced in the flame collision part of the combustion chamber, and the flame can be stabilized. Therefore, it is possible to achieve good combustion even in a state where the air ratio is increased and the flame temperature is low, making it possible to achieve low No. However, unlike wire mesh, the combustion chamber wall has multiple flame holes, so the jet flow velocity is high and the flames that face each other collide with each other (radiating heat to the combustion chamber wall), increasing the flame area and causing the flame to explode. The temperature decreases, further promoting low No. On the other hand, when the combustion amount is reduced, since opposed flames are formed, flame stability is good, and compared to wire mesh, heat loss is less, so good combustion can be achieved. This is also effective in expanding TDR. Additionally, burners are generally more likely to be cooled around the periphery, so by arranging the flame holes sparsely in the center and densely in the periphery, it is possible to equalize the temperature and speed distribution, resulting in higher performance. This makes it possible to achieve

EXAMPLE A specific explanation will be given below using the drawings. FIG. 1 is a partially sectional perspective view showing an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the burner. The main part of the burner is the outer wall 1,
It is composed of a combustion chamber wall 2 and a side plate 3, and the combustion chamber wall 2 is
Two plates are provided facing each other, a side plate 3 and a bottom plate 4.
A combustion chamber 5 is formed. In addition, a plurality of flame holes 6 are provided in the combustion chamber wall 2, sparse in the center and dense in the periphery.Similar to the combustion chamber wall 2, the flame holes 6 are also placed in opposing positions. be. Combustion chamber wall 2 and outer wall 1 form a mixing chamber 7
is formed, and on the upstream side there are a throat 8, a vaporization chamber 9, and a vaporization tube 1o, and a sheathed heater 1 is installed in the vaporization tube 1o.
1 is installed. Furthermore, an air passage 12 is communicated with the carburetor 10, and a fuel injection nozzle 13 is provided inside.
There is. The igniter 14 and combustion detector 1 are still installed in the combustion chamber 5.
There are 6.

Next, we will explain the operation. First, when using liquid fuel, the sheathed heater 11 is energized, and the vaporization cylinder 10 is turned on.
liquid fuel 16 from the revenge fuel injection nozzle 13 that heated the
gush out. After the liquid fuel 16 collides with the vaporization cylinder 10, vaporizes, and mixes with the air 17 sent at the same time, it passes through the throat 8 and becomes a uniform air-fuel mixture 18. Thereafter, it passes through the mixing chamber 7 and is supplied to the combustion chamber 5 through the flame hole 6, and is ignited by the igniter 14 to form an opposing flame 19. After combustion, it is discharged as exhaust gas 2o.

On the other hand, when gaseous fuel is used, the vaporization tube 1° is not required, and the downstream side of the throat 8 can be used with the same configuration as when using liquid fuel.

In this way, the opposing flame 19 formed is transmitted to the combustion chamber 5.
A stagnation point is formed in the center of the flame, where the flow velocity decreases and the flame is stabilized. Therefore, stable combustion can be achieved even in a region with a large air ratio, making it possible to reduce NOx.

On the other hand, when the combustion amount is reduced, good combustion can be achieved due to the formation of opposing flames 19, so that the TDR can be increased.

Furthermore, since the combustion chamber wall 2 is provided with a plurality of flame holes 6, the jet flow velocity of the flame 19 is higher than when using a wire mesh, and the flames 19 collide with each other, causing heat to be radiated to the combustion chamber wall 2. The flame area becomes larger and the flame temperature decreases, resulting in even lower NO.
x-ization can be promoted. On the other hand, even when the amount of combustion is reduced, stable combustion can be achieved because the heat loss is smaller than with wire mesh, etc., and it is also useful in increasing TDR.

In addition, since the temperature distribution and speed distribution of burners are generally not uniform, NO cracking and C (g) often occur locally, and the arrangement of the flame holes 6 as in the burner of one embodiment of the present invention often occurs locally. Performance can be improved by making the central part sparse and the peripheral part dense.

FIG. 3 is a sectional view taken along line AA in FIG. In a burner, the periphery is easily cooled and the center is easily overheated, so CO is easily generated from the periphery and No 2 is easily generated from the center. The flame hole 6 shown in FIG. 3 has a dense surrounding area.
They are sparsely arranged in the center, thereby achieving uniformity as a burner. In FIG. 3, the peripheral portion is arranged in one row, but depending on the temperature distribution, it may be arranged in two or more rows.

Furthermore, backfire can be prevented by making the diameter of the flame hole 6 smaller than the extinguishing distance.

Further, since the combustion chamber wall 2 has a structure in which a large number of holes are provided in a plate, it is easy to process, it is easy to reduce costs, and it is less susceptible to thermal deformation than a wire mesh or the like.

As explained above, according to the burner of the present invention, the following effects can be obtained. First, since the opposing flames stabilize the flame and allow combustion to occur in a region with a large air ratio, it is possible to achieve low NOx. Next, since good combustion can be achieved even when the combustion amount is reduced, TDR can be increased. In addition, since the flame holes are provided in the combustion chamber wall, the flame jet flow velocity is high, the flames collide with each other, the flame area increases, and the flame temperature decreases, further promoting low No. On the other hand, even when the combustion amount is reduced, heat loss is reduced, so stable combustion can be performed, which is also effective in increasing TDR. Furthermore, by spacing out the arrangement of flame holes, locally generated NOx and Co2 can be suppressed and a uniform burner can be achieved. In addition, the combustion chamber walls are easy to process, making it easy to achieve cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view of a burner according to an embodiment of the present invention;
Figure 2 is a vertical cross-sectional view of the burner, and Figure 3 is A-A in Figure 2.
FIG. 2... Combustion chamber wall, 6... Combustion chamber, 6.
...flame hole, 7...mixing chamber, 10...
... Vaporizer cylinder, 11... Sheathed heater, 14...
...Igniter. Name of agent: Patent attorney Toshio Nakao and 1 other person2-
Rirenj complete wall

Claims (1)

[Claims] A combustion chamber is formed by at least one pair of combustion chamber walls having a plurality of flame holes facing each other at a fixed distance, and each flame hole is coaxially opposed to each other between the opposing combustion chamber walls. A burner characterized in that the flame holes provided in the combustion chamber wall are arranged sparsely in the center and densely in the periphery, and a mixing chamber is provided between the combustion chamber wall and the outer wall.