JPH02290409A - Burner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a burner for commercial or domestic use.

2. Description of the Related Art Conventionally, there has been a burner shown in FIG. 8 for industrial and domestic stoves, fan heaters, etc., which utilizes combustion heat as a heat source. In FIG. 8, first, at the time of ignition, the sheathed heater 2 embedded in the vaporizer cylinder 1 is heated. After that, a fuel 4 such as kerosene is injected into the carburetor tube 1 from the fuel injection nozzle 3.
After being sent into the air, vaporized, and mixed with the primary air 5 that was sent at the same time, it passes through the throat 6 and becomes a homogeneous mixture 7.

The air-fuel mixture 7 passes through the pressure equalizing plate 8, is ejected from the flame hole 9, and is then ignited to form a flame lO. When the primary air ratio (air ratio of primary air) is 1 or more, secondary air is not required, but when the primary air ratio is less than 1, secondary air is supplied from the surroundings for complete combustion. was. That is,
Such a burner has been used as a heating heat source by performing combustion with partial premixing or complete premixing, and radiating the heat received from the flame 10 through the wire gauze forming the flame hole 9.

Another conventional example is shown in FIG. As in the case of FIG. 8, the fuel l2 is vaporized in the vaporization cylinder 11, mixed with air l3, and becomes an air-fuel mixture 14, which forms a flame hole 15 made of wire mesh.
is supplied to the combustion chamber l6. After ignition, flames 17 are formed, and since the flame holes 15 are provided facing each other, the flames 17 are also formed facing each other. At this time, since the flame hole 15 was a wire mesh, the flame 17 adhered to the surface of the wire mesh and burnt in a plane.

Problems to be Solved by the Invention However, in the conventional burner shown in Fig. 8, the flame tends to blow out when the combustion amount is increased, and the variable range of the combustion amount (hereinafter referred to as T.D.R.) is narrow. There was a problem. Further, even when the combustion amount is small, the flame is likely to be blown away when the primary air ratio is large, and backfire is likely to occur when the primary air ratio is small (near 1).

On the other hand, in the burner shown in FIG. 9, the flames are formed facing each other, so the flow velocity decreases at the flame collision part, making it difficult for the flame to blow away. However, since the flame burns in a plane on the surface of the wire mesh, the stability after floating was low, and the effect of suppressing blow-off was limited. The burner shown in Figure 9 is also prone to backfire, and when performing partial premix combustion at low combustion rates, the temperature inside the combustion chamber may be low and an appropriate amount of secondary air cannot be supplied into the combustion chamber. Carbon oxide (
There also remained the problem that CO (hereinafter referred to as CO) was likely to occur. Furthermore, even in the case of partially premixed combustion at high combustion rates, it has been difficult to shorten the secondary flame. In particular, since the secondary flame is cone-shaped in the center of the burner, if a heat exchanger or the like is installed downstream of the burner, the secondary flame may come into contact with the heat exchanger or the like and generate CO.

In other words, conventional burners cannot be said to have secured a sufficient combustion range in terms of both combustion amount and primary air ratio. Furthermore, since a wire mesh was used in the flame hole, the wire mesh was easily overheated and deteriorated.

The present invention provides a burner that can suppress flashback and blow-off when the combustion amount is low, and promote short flame length when the combustion amount is high.

Means for Solving the Problems In order to solve the above problems, the present invention has a pair of left and right primary combustion chamber walls having a plurality of flame holes facing each other at a fixed distance, and the primary combustion chamber walls, side plates, and bottom plate form a primary combustion chamber. A mixture supply system in which a pair of left and right flame holes are opposed to each other, a mixture branch pipe is provided on the air-fuel mixture upstream side of the primary combustion chamber, and the flame hole communicates with the primary combustion chamber and the mixture branch pipe. A plurality of flame holes are arranged in the direction of the outlet of the primary combustion chamber, and a wall of the secondary combustion chamber is provided downstream of the outlet of the primary combustion chamber to form the secondary combustion chamber. A plurality of secondary air injection holes are provided on the wall of the secondary combustion chamber, and a plurality of secondary air slits are provided at the upstream end of the secondary combustion chamber that is in contact with the primary combustion chamber. The slits are located outside the wall of the primary combustion chamber, and the positions of the secondary air slits and the flame holes are arranged approximately in a diagonal pattern when viewed from the center of the primary combustion chamber.

Effect: With the above configuration, opposing flames are formed in the primary combustion chamber,
The flow velocity decreases at the flame collision part, improving flame stability, making it difficult for the flame to blow away even if the combustion amount or primary air ratio increases.

In addition, the secondary air slit is divided into multiple pieces and is located outside the primary combustion chamber wall, so even when the primary air ratio is small (less than 1), an appropriate amount of secondary air can be delivered. Air flows uniformly into the secondary combustion chamber from the secondary air slit, forming multiple stable secondary flames with uniform flow velocity and temperature distribution, suppressing CO generation and achieving good combustion. . This effect becomes particularly noticeable when the temperature inside the combustion chamber is low and the combustion amount is low, making it difficult to oxidize CO.

In addition, the secondary air slit is divided into multiple parts, and the position of the secondary air slit and the position of the flame hole are arranged in a roughly chiseled shape when viewed from the center of the primary combustion chamber, so partial pre-heating is achieved when the combustion amount is high. In the case of mixed combustion, secondary air is supplied between each primary flame formed in a plurality of flame holes to form a plurality of small secondary flames.

Therefore, the secondary flame can be shortened and the shape of the secondary flame can also be changed depending on the position of the secondary air slit, making it easier to suppress the generation of CO even when a heat exchanger or the like is provided downstream of the burner.

EXAMPLE Hereinafter, the present invention will be specifically explained with reference to the drawings. The sectional view, FIG. 3, is a sectional view taken along the line B--B in FIG. 1.

The main parts of the burner are the primary combustion chamber wall l8 and the bottom plate l.
B and the side plate 20 form a primary combustion chamber 21, and two primary combustion chamber walls I8 are provided so as to face each other. Further, a plurality of flame holes 22 are provided in the primary combustion chamber wall l8, and the flame holes 22 are coaxially opposed to each other. A mixture branch pipe 23 is provided on the mixture upstream side of the primary combustion chamber 2l,
The flame hole 22 is located at the downstream outlet of the mixture supply path 24 that communicates the primary combustion chamber 2I and the mixture branch pipe 23,
A large number of flame holes 22 are arranged in the direction (upward) of the outlet 25 of the primary combustion chamber 2l. Further, on the downstream side (upper side) of the primary combustion chamber 2l, a secondary combustion chamber wall 26 is provided to form a secondary combustion chamber 27, and a plurality of secondary air jet holes 28 are provided in the secondary combustion chamber v2G. ing. Unlike the flame hole 22, the secondary air nozzle 2 does not need to be coaxially opposed to each other. Further, a plurality of secondary air slits 29 (Fig. 3) are provided at the upstream end (lower end) of the secondary combustion chamber 27 in contact with the primary combustion chamber 2l. It is located outside the primary combustion chamber wall l8. Furthermore, the positions of the secondary air slits 2B and the flame holes 22 are arranged in a substantially zigzag shape when viewed from the center of the primary combustion chamber 2l. At this time, the flame hole 22 to be arranged in a substantially zigzag manner is the flame hole 22 located closest to the secondary air slit 29. The area of the secondary air slit 29 is desirably such that it can supply into the secondary combustion chamber 27 an amount of secondary air sufficient to perform good partial premix combustion when the combustion amount is low. Also, primary combustion chamber 2! A mixing chamber 30 is provided on the lateral side of the side plate 20 forming a
2 has a sheathed heater 33 embedded therein. Vaporizer 32
A primary air passage 34 is communicated with the main body, and a fuel injection nozzle 35 is provided inside. Furthermore, the secondary air 3
A secondary air cover 37 is installed so that B can flow.

However, those without the secondary air cover 37 are also covered by the present invention.

The above is a configuration when using liquid fuel, but when using gaseous fuel, the vaporization tube 32 is not required, and the downstream side of the mixing chamber 30 can be used with the same configuration as when using liquid fuel.

Next, the operation will be explained. First, the sheathed heater 33 is energized to heat the vaporized w32, and then the fuel 38 is ejected from the fuel ejection nozzle 35. The fuel 38 is vaporized in the vaporizer 32 and mixed with the primary air 39 sent at the same time to form an air-fuel mixture 40 that flows into the mixing chamber 30. After that, it moves to the mixture branch pipe 23, and the plural mixture supply paths 24
It passes through and is supplied to the primary combustion chamber 2l from the opposing left and right flame holes 22, and after being ignited, forms an opposing flame 4l. On the other hand, the secondary air 36 flows in from the secondary air passage 42, passes through the secondary air cover 37, and is supplied to the secondary combustion chamber 27 from the secondary air slits 29 and 7 secondary air jet holes 28, and is stabilized. Even when the secondary flame 43 is formed and the primary air ratio is less than 1, the combustion gas is exhausted after being completely combusted. When the combustion amount is large, the secondary flame 43 tries to expand, but due to the secondary air 36 supplied from the secondary air jet hole 28,
Efforts are being made to shorten the flame.

The opposed flames 41 thus formed have a flow velocity reduced at the flame collision portion of the primary combustion chamber 2I, and a stagnation region is formed to stabilize the flame. Therefore, even if the combustion amount or primary air ratio increases, the flame is less likely to blow off compared to conventional burners. On the other hand, when the combustion amount and primary air ratio are small (near 1), the flame enters the flame hole 22 and tries to backfire. However, since the primary combustion chamber wall l8 and the air-fuel mixture supply path 24 are cooled by the secondary air 36, the flame does not backfire.
Stable combustion can be achieved near the flame hole 22. Even if there is no secondary air cover 37, the primary combustion chamber wall I8 and the air-fuel mixture supply path 24 are exposed to the outside air, so they are cooled by natural convection, although not as much as forced cooling by the secondary air 3G, and the flame is reversely cooled. It is difficult to catch fire.

Therefore, as a burner, T. D. R. It becomes possible to widen the area.

FIGS. 4(a) and 4(b) are detailed views of the opposing flame 41 when combustion toxicity is low. When the combustion amount is small and the primary air ratio becomes large, the opposing flame 4l moves away from the flame hole 22, as shown in FIG. 4(a). At this time, some CO is generated near the flame holes 22, but since many flame holes 22 are arranged in the vertical direction, the generated CO is absorbed into the primary combustion chamber 2l.
Opposing flame 4 on the outlet 25 side (above the primary combustion chamber 2I)
It is oxidized by I. Therefore, even if the opposing flame 4l separates from the flame hole 22, the exhaust gas characteristics of the burner will not deteriorate. In particular, in the upper direction of the primary combustion chamber 21, the temperature near the flame hole 22 also rises, so the temperature at the primary combustion chamber outlet 2
5, the opposing flame 4l approaches the flame hole 22, and the C
Generation of O is suppressed. Furthermore, when the primary air ratio decreases and becomes less than 1, the opposing flame 41 comes to adhere to the flame hole 22, as shown in FIG. 4(b).

At this time, the secondary air 36 is supplied into the secondary combustion chamber 27 from the secondary air slit 29 and the secondary air jet hole 28, but the secondary flame 43 formed here cannot be stabilized. Otherwise, CO will be generated.

Therefore, in this embodiment, the secondary air slit 29 is divided into a plurality of pieces to make the flow of the secondary air 36 uniform, and the secondary flame 43 is divided into small parts, thereby improving flame stability. Furthermore, the amount of secondary air sent through the secondary air/slit 29 is also optimized. That is,
The amount of secondary air that prevents the stabilization of the secondary flame 43 is made to flow out from the secondary air nozzle 28, and the amount of secondary air that is sufficient to perform good partial premix combustion at a low combustion amount is released from the secondary air slit 29. is supplied into the secondary combustion chamber 27 to stabilize the secondary flame 43. In addition, secondary air slit 2
By locating 9 outside the primary combustion chamber wall I8, the flow velocity of the secondary air 3B can be reduced and turbulence can be removed, thereby preventing the stabilization of the opposing flame 41 or overcooling. CO is also less likely to be generated.

The case where the combustion amount is small has been described based on FIGS. There is a problem in that it comes into contact with a heat exchanger etc. installed on the downstream side and tends to generate CO. In particular, this tendency becomes more noticeable if the secondary air slit 29 is formed into one elongated strip-like slit without being divided.

In contrast, in this embodiment, the secondary air slit 29 is divided into a plurality of parts, and the positions of the secondary air slit 29 and the flame hole 22 are arranged in a substantially zigzag shape when viewed from the center of the primary combustion chamber 21. Therefore, secondary air 36 is supplied between the plurality of opposing flames 41 (primary flames), forming a plurality of small secondary flames 43 as shown in FIG. Since the secondary air 36 enters between the primary flames instead of above them, it is possible to further promote the shortening of the secondary flame 43. Therefore, even when a heat exchanger or the like is provided downstream of the burner, the generation of CO is suppressed and high-load combustion is facilitated.

Further, since the secondary air slit 29 is divided into a plurality of small parts, it is easy to process without causing thermal deformation.

In addition, unlike conventional burners, wire mesh is not used in the 9th part of the flame hole (see Figure 8), and the primary combustion chamber wall 18 also has a secondary air 36.
Since the system is cooled by flowing water, deterioration due to overheating is less likely to occur.

Even when the secondary air 36 is not flowing, the cooling effect is slightly reduced, but since the primary combustion chamber wall I8 is exposed to the outside air, the primary combustion chamber wall I8 is cooled by natural convection.

FIG. 6 shows a sectional view (corresponding to the BB sectional view in FIG. 1) of a burner in a second embodiment of the present invention.

In FIG. 6, two (two sets) of secondary air slits 29a
The area of the secondary air slit 29 is made larger than the area of the other secondary air slits 29. Therefore, a large amount of secondary air 36 flows in from the secondary air slit 29a, and the nearby secondary flame 43 is further shortened. Furthermore, the burner as a whole also has a secondary flame of 43
will be divided into three parts. By changing the shape of the secondary flame 43 in this way, when a heat exchanger or the like is provided on the downstream side of the burner, it becomes easier to adapt to the setting position and the shape of the heat exchanger.

FIG. 7 shows a sectional view of a burner according to a third embodiment of the present invention (a secondary flame is shown in a view corresponding to the BB sectional view in FIG. 1).

In FIG. 7, the flame holes 22 at both ends are provided at positions closer to the side plate 20 than the secondary air injection holes 28 at both ends. Therefore, the combustion gas flow within the burner is directed toward both ends, and the secondary flames 43 at both ends are significantly elongated. Since the secondary flame 43 in the center is not cone-shaped as in the conventional case but has a short flame, according to the burner of this embodiment, the heights of the tips of the secondary flames 43 can be made to match. It becomes possible. Therefore, by installing a heat exchanger or the like on the downstream side of such a burner, it is possible to heat evenly and uniformly in the longitudinal direction. In FIG. 7, the flame holes 22 at both ends are located closer to the falling plate 20 than the secondary air jet holes 28 at both ends, but the flame holes 22 at both ends are positioned closer to the falling plate 20 than the secondary air slits 29 at both ends. It may be provided at a position close to the side plate 20.

As explained above based on each example,
If the amount of secondary air sent in from the secondary air slit 2B is too large, the secondary flame 43 will be disturbed and supercooling will be promoted, making it easier for CO to be generated in the case of partially premixed combustion at a low combustion amount. . Furthermore, as a result of the experiment, the secondary air slit 2
It was confirmed that the larger the total area of the secondary air ejection holes 28 compared to the total area of the secondary air ejection holes 28, the more pronounced the tendency for CO to increase. Therefore, by making the total area of the secondary air slits 29 smaller than the total area of the secondary air injection holes 28, good combustion performance can be ensured.

In addition, as for the one in which the secondary air cover 37 is provided so that the secondary air 36 flows around the mixture branch pipe 23 and the mixture supply path 24, the cooling effect is not only increased as described above, but also The presence of the secondary air cover 37 prevents combustion gas from leaking from the primary combustion chamber 2l to the outside, thereby further increasing the reliability of the combustion apparatus.

Effects of the Invention As explained above, according to the burner of the present invention, the following effects can be obtained.

First, by forming opposing flames and cooling the upstream side of the flame hole, flame blow-off and backfire are suppressed, and T.
D. R. It becomes possible to widen the area.

In addition, by dividing the secondary air slit into multiple pieces and positioning the secondary air slit outside the primary combustion chamber wall, the primary air ratio is small (less than 1) at low combustion levels.
Even in the case of partially premixed combustion, it is possible to suppress the generation of co and achieve stable combustion.

In addition, by making the positions of the secondary air slits and the flame holes almost chiseled when viewed from the center of the primary combustion chamber, even in the case of partial premix combustion at high combustion rates, the secondary air can flow into the opposing flame. It can penetrate into the gap between the burners and promote the shortening of the secondary flame, and even when a heat exchanger or the like is provided downstream of the burner, the generation of CO can be suppressed, making it easier to achieve high-load combustion.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a burner in a first embodiment of the present invention;
Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view taken along line B-- in Figure 1.
B cross-sectional view, Figures 4(a) and 4(b) are detailed cross-sectional views of the opposing flames when the combustion amount is low. Fig. 5 is a cross-sectional view showing the secondary flame when the primary air ratio is small (1 g!) at a high combustion rate, and Fig. 6 is a cross-sectional view showing the secondary flame when the primary air ratio is small (1 g!). 7 is a cross-sectional view of the burner in the second embodiment, and FIG. 7 is a cross-sectional view of the burner in the third embodiment of the present invention.
The figure is a sectional view of a conventional burner. 18. ．． ．． Primary combustion chamber wall, 19. ．． ．． Bottom plate, 20. ．． ．．
Side plate, 21. ．． ．． Primary combustion chamber, 22. ．． ．． Flame hole, 23.
．． ．． Mixture branch pipe, 24. ．． ．． Mixture supply path, 211i
．． ．． ．． Secondary combustion chamber wall, 27. ．． ．． Secondary combustion chamber, 2B. ．．
．． Secondary air outlet, 29. ．． ．． Secondary air slit, 32
．． ．． ．． Vaporizer cylinder, 37. ．． ．． Name of secondary air cover agent Patent attorney Shigetaka Awano 1 person 1st figure / 8 --- 1 dog f foot 1 helmet / 9 -- 1 hire hai l no - 1 1 sentence me roast praise 8 harm! 22-11 flame light 23-11 situation to @ R pipe 24 ---
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Claims (5)

[Claims] (1) A pair of left and right primary combustion chamber walls having a plurality of flame holes are opposed to each other at a certain distance, the primary combustion chamber wall, side plate, and bottom plate form a primary combustion chamber, and the left and right flame holes of the pair are opposed to each other. and a mixture branch pipe is provided on the upstream side of the mixture of the primary combustion chamber, and the flame hole is located at a downstream outlet of a mixture supply path that communicates the primary combustion chamber and the mixture branch pipe. A secondary combustion chamber is formed by arranging a large number of the plurality of flame holes in the direction of the outlet of the primary combustion chamber, and providing a secondary combustion chamber wall downstream of the outlet of the primary combustion chamber. A plurality of secondary air ejection holes are provided in the combustion chamber wall, and a secondary air slit is provided divided into a plurality of pieces at the upstream end of the secondary combustion chamber in contact with the primary combustion chamber, and the secondary air slit is divided into a plurality of pieces. A burner characterized in that the burner is located outside a wall of the primary combustion chamber, and the positions of the secondary air slit and the flame hole are arranged in a substantially diagonal shape when viewed from the center of the primary combustion chamber. (2) The burner according to claim 1, wherein the area of at least one of the plurality of secondary air slits is larger than the area of the other secondary air slits. (3) The burner according to claim 1, characterized in that the flame holes at both ends are provided at a position closer to the side plate than the secondary air slits at both ends or the secondary air jet holes. (4) The burner according to claim 1, wherein the total area of the secondary air slits is smaller than the total area of the secondary air ejection holes. (5) The burner according to claim 1, further comprising a secondary air cover so that secondary air flows around the mixture branch pipe and the mixture supply path.