JP3526938B2 - Flat frame burner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat flame burner for spreading a flame in a radial direction immediately after injection to form a flat flame along an inner wall of a furnace.

[0002]

2. Description of the Related Art A conventional flat frame burner of this type swirls or goes straight to the center of the burner throat by the combustion air swirling in the burner throat and entrains the injected gas fuel to swirl it to the furnace wall. It forms a flat flame along it. In this burner, the flame does not spread flatly at low load when the swirl force weakens, and when the load is high, the combustion exhaust gas is sucked by the negative pressure generated at the center of the burner throat by the swirl force of the air, lowering the oxygen concentration and making the flame unstable. There is a problem.

Therefore, as shown in FIG. 7, the fuel gas pipe 1
01 is provided with an axial flow swirler 102 at a circumferential position and a gas ejection hole 103 is provided on the upstream side of the axial flow swirler 102.
A part of the fuel injected from the swirler 102 at the end of 01 is made to flow back into the negative pressure region generated downstream of the axial swirl 104, and the fuel gas injected from the gas ejection holes 103 on the circumferential surface of the gas pipe is supplied. It has been proposed to further mix them to form the flame holding region 105 (Jitsuko Sho 62-34111). Here, the gas ejection holes 103 formed in the peripheral surface of the fuel gas pipe 101 are pilot holes for enhancing the flame holding performance under low load, and the flame holding region 105 has a gas concentration of about 0.9 air ratio. .

[0004]

However, since the fuel injected in the radial direction is the pilot fuel for stabilizing the flame and not the main fuel injection hole, most of the fuel is injected in the axial direction. Therefore, during low combustion when the swirling force of the combustion air becomes weaker, even if the fuel itself is swirled, the rectilinear force of the fuel exceeds the centrifugal force and the mixing of air and fuel deteriorates, forming a red fire. Or the combustibility at the time of low combustion may be deteriorated. In particular, when using a calorific value high gas such as propane or butane as the fuel, the gas flow itself becomes small, the combustion of low combustion time will increasing amount flowing in the axial direction <br/> is make worse. Also,
In this conventional flat flame burner, increasing the radial fuel mixes well with air and receives a strong swirling force, so the combustibility in the low combustion range can be improved and a hollow blue fire (good mixed flame) Can be formed, but in the high combustion region, it is blown off by receiving a strong radial centrifugal force at the outlet of the burner tile tip. Therefore, the turndown ratio cannot be increased.

Further, since high-load combustion is carried out in a narrow burner throat, when the radial fuel is increased, a large flame hits the swirling flow of the burner tile and the combustion air to cause oscillatory combustion. There is.

The pressure distribution of air in the throat of the flat flame burner when not burning is the lowest on the central axis, gradually increases toward the outer side in the radial direction, and reaches the maximum on the inner wall surface of the throat. Therefore, a phenomenon occurs in which air enters the fuel gas pipe 101 from the radial injection holes 103 and exits from the swirler 102 at the tip. In this case, less fuel than the fuel at the time of minimum combustion is further diluted and flows out from the axial injection hole at the tip, so that fuel is not supplied into the circulation vortex downstream of the deflector and ignition cannot be performed. In particular, when a gas having a high calorific value such as propane or butane is used as a fuel, the gas flow rate decreases, so that the gas is not ejected from the gas injection hole 103 and gas is emitted only in the axial direction from the tip end, so that the flame retaining plate is used. Since the fuel will not return to the side, it will be necessary to ignite at a low air ratio. For example, what was ignited even at a high air ratio of 1:20 when it was not contained in the burner throat, but when it was contained in the burner throat, it did not ignite unless it was set to 1: 1.3 or less. Therefore, it is difficult to apply it to a pilotless burner.

Further, the burner tile 106 is usually heavy because it is integrally formed by using a heat insulating material having a low thermal conductivity such as castable refractory to prevent heat dissipation. Moreover, because the combustion air swirls, the flame licks the inner surface of the burner tile,
There is a problem that the temperature of the inner surface of the burner tile rises and the temperature difference of the burner tile becomes large, so that the burner tile easily cracks.

Further, the flat frame burner shown in FIG.
Since the axial swirler 104 is used, the field of view can be taken only at the center, so that the fuel gas pipe 101 is narrowed at that portion.
It becomes difficult to install a viewing window or an ignition rod if you place the. Therefore, there is a problem that the entire burner becomes large. Further, since the axial flow swirler 104 is incorporated so as to be fixed to the fuel gas pipe 101, the swirler 10
4 cannot be replaced or cleaned easily.

An object of the present invention is to provide a flat flame burner capable of stable combustion without causing oscillating combustion. It is another object of the present invention to provide a flat flame burner that ensures reliable ignition. A further object of the present invention is to provide a flat frame burner capable of increasing the turndown ratio.

[0010]

In order to achieve the above object, the present invention provides a fuel pipe for injecting gas fuel in a flat frame burner in which a flame is spread from a burner tile and ejected to form a flat flame along an inner wall of a furnace. Two or more rows of radial injection holes are provided at the tip of the column in the flow direction of the combustion air, and a flame holding plate is provided upstream thereof, and the radial fuel injection holes in the row closer to the flame holding plate also serve as a pilot. As a fuel injection hole, the minimum amount of fuel required for pilot ignition is injected therein, and the remaining fuel is injected from the radial fuel injection holes of other rows .

Further, in the flat frame burner of the present invention, an axial fuel injection hole is provided at the tip of the fuel pipe.

Further, the flat frame burner of the present invention is provided with a pressure equalizing chamber which is in communication with the fuel injection hole in the axial direction of the fuel pipe and which does not cause combustion air to swirl inside.

Further, the burner tile of the flat frame burner of the present invention is composed of a thin material having a high thermal conductivity which constitutes the throat surface and a backup material of a material which supports the throat surface and has a low thermal conductivity and a high heat insulating property. It is characterized by

Further, the flat frame burner of the present invention is a flat frame burner which spreads and ejects a flame from an injection hole, and an annular recess is provided on the inner surface of the wind box on the flange at the rear end of the burner, and the burner is fitted into the recess. A swirler that swirls air almost tangentially along the throat is detachably attached.

[0015]

Therefore, in the case of the flat frame burner according to claim 1, the fuel injected from the radial fuel injection hole on the downstream side of the radial fuel injection holes provided in two or more rows is the same as the fuel flowing downstream. It flows backward on the upstream side of the pipe surface to form a vortex that reaches the flame holding plate and is divided into fuel that forms a flame at the edge of the flame holding plate. Further, the minimum amount of fuel required for pilot ignition is injected from the upstream radial fuel injection hole closest to the flame holding plate, and the mixture concentration in the vortex is made into a rich fuel that can be ignited. Therefore, it is possible to easily ignite an electric spark (spark ignition) on the back surface (downstream side) of the flame holding plate. Moreover, when burning, it becomes a pilot fire to stabilize the combustion. On the other hand,
Most of the fuel injected from the radial fuel injection holes distant from the flame stabilizing plate gently changes its flow direction to the downstream side and does not cause oscillatory combustion.

Further, in the case of the flat frame burner according to the second aspect, a part of the fuel is also injected in the axial direction. At low combustion, this axial fuel is surrounded by a swirling flame mainly composed of radial fuel, so that it burns but has poor mixing properties, resulting in red fire. However, at the time of high combustion, it is strongly influenced by the swirling force to enhance the mixing property with the combustion air and spread, and burns while covering the swirling flame around it from the inside. Therefore, even if the flame swirl force of the radial fuel becomes strong and the flame enters the furnace and is blown off by a strong centrifugal force and tries to be blown off, a flat flame is formed by the flame of the axial fuel covering it. To be done.

Further, in the case of the flat frame burner according to the third aspect, the phenomenon that air enters from the radial injection hole in the fuel pipe and exits from the axial injection hole is suppressed. The pressure distribution of the combustion air in the burner throat before ignition is lowest in the fuel pipe on the central axis, gradually increases outward in the radial direction, and becomes maximum on the inner wall surface of the throat. At this time,
In the pressure equalizing chamber, the swirling of the combustion air is disturbed and the centrifugal force does not act, so the pressure difference between the pressure equalizing chamber and the outside becomes small,
A phenomenon in which air enters from the radial injection holes and exits from the axial injection holes in the fuel pipe communicating with the axial injection holes is suppressed. For this reason, the fuel also flows out from the radial injection holes and flows back to the flame holding plate side so as to cover the surface of the fuel pipe, and supplies the fuel into the vortex flow. Once ignited, the gas density in the throat drops extremely, the centrifugal force also weakens, the pressure difference between the central axis of the throat and the vicinity of the throat inner wall almost disappears, and the fuel injection amount from the radial injection holes also increases.

Further, in the case of the invention of claim 4, even if the temperature of the inner surface of the burner tile rises due to the flame licking the inner surface of the burner tile due to the swirling of the combustion air, the material forming the burner throat surface is thin. Moreover, since the burner tile is made of a material having a high thermal conductivity, the temperature difference between the burner tiles becomes small and the burner tile does not crack. Moreover, since the material forming the burner throat surface is backed up by a material having excellent heat insulating properties, heat diffusion is suppressed.

Further, in the case of the present invention as defined in claim 5, since the swirler is fixed only by fitting it in the recess of the burner flange, it can be easily attached and detached as required.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the flat burner of the present invention. This flat burner includes a fuel pipe 1 having fuel injection holes 2, 3 and 4 for injecting fuel gas at its tip, a burner tile 6 surrounding the fuel pipe 1 to form a burner throat 5, and a burner throat 5 burning in the burner throat 5. A radial swirler 7 that swirls and introduces the working air, and a wind box 8 that surrounds the swirl 7 and introduces the combustion air around it.
And an observation window 10 for observing the ignition rod 9 and the ignition condition and the flame condition.

The burner tile 6 and the wind box 8 have flanges 11 and 12 respectively on the surfaces facing each other, and are integrated by connecting the flange portions 11 and 12 with bolts or the like. The swirler 7 is detachably fixed to the burner flange 12 of the wind box 8 and the front of the fuel pipe 1 is further supported by the swirler 7. As a result, the fuel pipe 1 is supported on both sides by the swirler 7 and the rear end flange 13 of the wind box 8. Therefore, the core of the fuel pipe 1 can be easily taken out in the burner throat. The fuel pipe 1 has a rear end flange 13 and a swirler 7.
The end plate 17 of the burner throat 5 is provided so as to be movable in the front-rear direction, that is, to be able to move in and out of the burner throat 5. For example, the fuel tube 1 has a tubular holding member 30 provided on the end plate 17 and the rear end flange 13, respectively.
Supported by, and temporarily fixed with screws (not shown),
It is provided so that the position of the fuel tube 1 in the burner throat 5 can be changed and adjusted as needed.

As the swirler 7, it is preferable to employ a radial swirler (tangential swirler) for injecting combustion air almost tangentially. In this case, a high turning force can be obtained with a low air pressure, and the ignition of fuel can be stabilized. Moreover, since the field of view can be set on the entire surface of the burner throat 5, the fuel pipe 1 is of course disposed, and the sight window 1
It becomes easy to install 0, the ignition rod 9, and the like. The swirler 7 is detachably mounted in a recess 14 provided at the center of the burner flange 12 by fitting with a slight interference. Therefore, the swivel device 7 can be easily removed by pulling it backward. The swirler 7 injects air in a direction in which its outlet matches the inner peripheral surface (throat surface) 15 of the burner tile 6 and is substantially tangential to the inner peripheral surface 15.

The ignition rod 9 is inserted from the rear end flange 13 into the wind box 8 so that the tip of the ignition rod 9 approaches the flame holding plate 16 of the fuel tube 1, and a spark is formed between the ignition rod 9 and the flame holding plate 16. It is provided to fly.

Further, the viewing window 10 is inserted into the wind box 8 from the rear end flange 13 and is inserted into the end plate 17 of the swivel 7.
The tip of the burner throat 5 is fixed so that the inside of the burner throat 5 can be observed through the inside of the swirler 7.

The burner tile 6 has a straight tubular shape as a whole except for the vicinity of the outlet 18, and is provided so that the inner diameter thereof rapidly widens at the outlet 18 portion. As a result, the swirling flame retains its momentum up to the outlet 18 of the burner tile 6, and is spread at once at the outlet 18 to form a flat flame along the inner wall of the furnace. In the case of the present embodiment, the burner tile 6 is made of a thin material having high thermal conductivity, such as carborundum (SiC), for forming the burner throat surface 15, and a material having low thermal conductivity and high heat insulation. For example, the backup member 20 is made of fiber ceramics and supports the inner member 19. In this case, since most of the burner tile 6 is formed of the backup material 20 made of a lightweight heat insulating material, it is possible to significantly reduce the weight as compared with the conventional burner tile. Usually, lightweight materials such as fiber ceramic moldings and lightweight castables have problems with wind resistance. However, this backup material 20
Since the inner surface of is covered with the inner member 19 made of a hard material having a high thermal conductivity such as SiC, it becomes lightweight and small in size and excellent in wind resistance as a whole. Moreover, although a hard material such as SiC is usually vulnerable to thermal shock, the thin material reduces the temperature difference in the thickness direction to prevent cracking.

Two or more rows of fuel injection holes 2 and 3 are provided at the tip of the fuel pipe 1 in the radial direction, and the flame holding plate 16 is provided upstream of the radial fuel injection holes 2 and 3. Are arranged.
Since fuel injected in the radial direction is generally easy to blow out,
By providing a flame holding plate (deflector) 16 on the upstream side, flame stability is improved. Further, in the case of the present embodiment, ignition is performed by blowing an electric spark (spark ignition) on the back surface of the flame holding plate 16. In this case, ignition cannot be performed unless the mixture concentration on the back surface of the flame holding plate 16 is appropriate. Generally, it is easier to ignite when the ignition is carried out at a place slightly higher than the theoretical mixing ratio. Therefore, the flame holding plate 16
The radial fuel injection hole 3 in the row closer to is a relatively small diameter fuel injection hole that also serves as a pilot, and the minimum amount of fuel 32 required for pilot ignition is injected into the fuel injection hole, and the remaining fuel is used in the other rows. It is provided so as to inject from the radial fuel injection hole 2. In this case, the proportion of pilot fuel is 10 to the whole.
20% is suitable. Here, the fuel injected from the downstream radial fuel injection hole 2 flows directly to the downstream portion 21
And a portion 22 that flows backward so as to cross the surface of the fuel pipe 1. The part 22 that flows back reaches the flame holding plate 16,
After mixing with the fuel 32 injected from the radial fuel injection holes 3 in the row near the flame stabilizing plate 16, the fuel flows radially outward along the flame stabilizing plate 16 and flames at the edges of the flame stabilizing plate 16. To form. Then, the flame holding is carried out by utilizing the vortex 23 on the back surface of the flame holding plate 16 and the amount of the fuel flowing from the injection hole 3 is reversed.
It is carried out by mixing 2 and 2 to form a flame holding region having a high fuel concentration. The fuel concentration in the vortex 23 varies depending on the distance between the flame holding plate 16 and the radial fuel injection hole 2 on the downstream side for injecting the main fuel. For example, as the fuel injection hole 2 on the downstream side and the flame holding plate 16 are closer to each other, the fuel concentration is higher and the ignition becomes easier. Will result in damage to.
For this reason, it is preferable that the above-mentioned distances are separated as much as possible within a range where reliable ignition is possible.

According to the flat frame burner constructed as described above, the flat flame burner is burned as follows to form a flat flame. That is, the radial fuel injection holes 2 and 3 provided in two or more rows
Of the fuel injected from the injection holes 2 on the downstream side, the fuel 21 flows downstream as it is and flows backward to the upstream side so as to cross the surface of the fuel pipe 1 and reaches the flame holding plate 16 to reach the edge of the flame holding plate 16. It is divided into the fuel 22 that forms a flame at the (edge). Further, the minimum amount of fuel 32 required for pilot ignition is injected from the upstream fuel injection hole 3 closest to the flame stabilizing plate 16, and the concentration of the air-fuel mixture in the vortex becomes a ignitable rich fuel.
Therefore, it is possible to easily ignite the electric spark (spark ignition) on the back surface (downstream side) of the flame holding plate 16. Moreover, when burning, it becomes a pilot fire to stabilize the combustion. On the other hand, the radial fuel injection hole 2 separated from the flame holding plate 16
Most of the fuel 21 injected from the fuel tank slowly changes its flow direction to the downstream side and does not cause oscillatory combustion.

Further, according to the flat frame burner provided with only the radial fuel injection ports 2 and 3, since the radial fuel is well mixed with air, a hollow blue fire (good mixed flame) as shown is formed. . This blue fire is a hollow flame that sticks to the inner surface of the burner tile, so if the turndown ratio is increased and the amount of combustion is made larger than that of the conventional flat flame burner, in the high combustion range, it is at the exit of the burner tile tip. There is a possibility that it will be blown off by receiving a strong centrifugal force in the radial direction. Therefore, the injection port 4 for injecting the fuel 31 in the axial direction is provided at the tip of the fuel pipe 1 so that the turndown ratio can be made larger than that of the conventional flat frame burner.
The axial fuel 31 mixes poorly at low combustion and forms a red fire. However, when the combustion becomes high, the mixing gradually becomes good, and it turns into a blue fire. At the same time, the combustion position also moves to a position closer to the inner surface 15 of the burner tile instead of near the central axis of the throat, resulting in a hollow blue fire. . Then, the flame of the radial fuel is covered from the inside to prevent the flame of the radial fuel from blowing off. Therefore, when the axial fuel 31 is present, the high combustion limit is wider than when it is absent. On the other hand, the higher the proportion of the axial fuel 31, the wider the high combustion limit, but on the other hand, it becomes difficult to ignite. Therefore, there is a limit to the axial fuel ratio, and about 30% of the total is appropriate.

However, an axial injection hole 4 is formed at the tip of the fuel pipe 1.
By providing the above, a phenomenon occurs in which air enters from the radial injection holes 2 and 3 and flows out from the axial injection holes 4. Therefore, for example, when a gas having a high calorific value such as propane or butane is used as a fuel, the fuel is diluted with air and flows out from the axial injection hole 4, and the circulation vortex 23 on the back surface of the flame stabilizing plate 16 is used. There is a possibility that fuel cannot be supplied inside and ignition may be impossible. Of course, once ignited, the gas density in the burner throat 5 drops extremely, the centrifugal force also weakens, and the pressure difference between the central axis of the throat and the vicinity of the inner wall of the throat almost disappears. Therefore, fuel is also injected from the radial injection ports 2 and 3. It will come out.

Therefore, the axial injection hole 4 is provided at the tip of the fuel pipe 1.
A pressure equalizing chamber 24 that communicates with the above is provided. This pressure equalizing chamber 2
Numeral 4 is for stopping the swirling of the air flow inside it so that centrifugal force does not work. For example, as shown in FIG. 5, the tip of the fuel pipe 1 is extended to provide a tubular portion 26 on the downstream side of the axial injection hole 4 and the whirl stop blade 2 is provided inside thereof.
5 is provided. In this case, the pressure is almost equalized inside the extended portion 26, but it is not perfect because the negative pressure is transmitted because the front side is open. Also,
As shown in FIG. 6, the tip of the fuel pipe 1 is extended to provide a tubular portion 27 having a substantially closed tip on the downstream side of the axial injection hole 4, and a large number of pores 28 are provided in the tubular portion 27. May be. An injection hole 29 having a diameter slightly larger than that of the axial fuel injection hole 4 is provided at the tip of the tubular portion 27 at substantially the same position as the axial injection hole 4. In this structure, there is no swirl in the extension chamber, and therefore centrifugal force does not work. However, since the tip end has a hole 29 that is slightly larger than the original axial injection hole 4, the burner throat 5 is the same as in the case of FIG.
The negative pressure inside is transmitted. However, since the ambient air enters at the same time from a large number of pores 28, ..., 28 provided in the periphery, the negative pressure in the pressure equalizing chamber 24 is smaller than that in the case of FIG. Thus, the amount of air entering the fuel pipe 1 is greatly reduced, and the ignitability is remarkably improved.

In this case, the swirling of the combustion air is hindered in the pressure equalizing chamber 24 and the centrifugal force does not act, so the pressure difference between the inside and the outside of the pressure equalizing chamber 24 becomes small, and the axial direction injection hole 4 is used. The phenomenon that air enters from the radial injection holes 2 and 3 in the communicating fuel pipe 1 and exits from the axial injection hole 4 is suppressed. Therefore, the fuel mainly flows out from the radial injection holes 2 and 3 and flows back to the flame holding plate 16 side so as to cover the surface of the fuel pipe 1, and supplies the fuel into the vortex 23. Once ignited, the gas density in the throat drops extremely, the centrifugal force also weakens, the pressure difference between the central axis of the throat and the vicinity of the throat inner wall almost disappears, and the fuel injection amount from the radial injection holes 2 and 3 also increases. . Further, the axial fuel 31 is injected from the injection hole 29 or the front opening of the pressure equalizing chamber 24 through the pressure equalizing chamber 24.

It should be noted that the above-mentioned embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, although the present embodiment mainly describes the one having the axial fuel injection hole 4, the invention is not particularly limited to this, and only the radial fuel injection holes 2 and 3 have the axial fuel injection hole 4. It may not be done. Also in this case, it is effective to eliminate oscillating combustion and improve flame stability at low combustion.

[0034]

As is apparent from the above description, in the flat frame burner of the present invention, two or more rows of radial injection holes are provided in the combustion air flow direction at the tip of the fuel pipe for injecting gas fuel. A flame holding plate is provided upstream of them, and the minimum amount of fuel required for pilot ignition is injected into the radial fuel injection holes in the row closer to the flame holding plate as fuel injection holes that also serve as pilots, Remaining fuel in the other row
Since the fuel is injected from the facing fuel injection hole, a part of the fuel injected from the fuel injection hole on the downstream side flows backward to the flame holding plate side and is injected from the radial fuel injection hole closest to the flame holding plate. While it is mixed with the fuel to form a flame holding region of a swirl flow with a high fuel concentration to enable reliable ignition, the remaining fuel mixes with the surrounding swirling flow of combustion air while gradually spreading downstream. Since it burns outside the burner tile, vibrational combustion does not occur.

Further, in the case of the second aspect of the present invention, when the fuel injected in the axial direction is highly burned, the miscibility with the combustion air is enhanced and a blue fire that approaches the inner surface of the burner tile tends to be blown out in the radial direction. Since it covers the outer swirl flame formed by the fuel, blowout can be prevented. Therefore, the combustion range can be expanded and the turndown ratio can be increased to about 10: 1.

According to the third aspect of the invention, the pressure equalizing chamber prevents the pressure on the downstream side of the axial injection hole at the tip of the fuel pipe from becoming negative pressure. The flow of combustion air through the holes and the escape of the combustion air into the axial injection holes does not occur, and fuel can be injected through the radial injection holes. Therefore, even a small amount of pilot fuel can be reliably ignited, and the ignitability is improved especially when a gas having a high calorific value is used as the fuel.

Further, in the case of the invention of claim 4, since the burner tile is made of a thin material having a good thermal conductivity and a lightweight material having a high heat insulating property, it is possible to reduce the weight as a whole and to improve the wind resistance. Moreover, even if it is heated to a high temperature by the flame flowing along the inner surface of the burner tile, it is thin and there is no temperature difference, and cracking is reduced.

Furthermore, in the case of the fifth aspect of the invention, since the swivel can be easily removed, its replacement and cleaning are facilitated.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a schematic structure of a flat frame burner of the present invention.

FIG. 2 is an explanatory view showing a fuel injection situation in a burner throat of the burner shown in FIG.

FIG. 3 is an explanatory view showing a flow of fuel injected from each radial fuel injection hole of the burner shown in FIG.

FIG. 4 is a diagram for explaining an inflow state of combustion air into the fuel pipe of the burner shown in FIG. 1 during non-combustion, FIG. 4A is a diagram showing a pressure distribution of air in the burner throat during non-combustion;
(B) is a cross-sectional view of the fuel pipe showing the flow of air.

5A and 5B are views showing an embodiment in which a pressure equalizing chamber is provided at the tip of a fuel pipe, in which FIG. 5A is a vertical sectional view and FIG. 5B is a front view.

FIG. 6 is a vertical sectional view showing another embodiment of the pressure equalizing chamber.

FIG. 7 is a vertical sectional view showing a schematic structure of a conventional flat frame burner.

[Explanation of symbols]

1 fuel pipe 2 Downstream radial fuel injection hole 3 Radial fuel injection hole closest to flame holding plate 4 Axial fuel injection hole 5 burner throat 6 burner tiles 7 swivel 11,12 burner flange 14 Recessed part to fit swivel 7 16 flame plate 19 Inner member that constitutes the throat surface of burner tile 20 Backup materials that make up burner tiles 21 Part of radial fuel that flows directly downstream 22 Part of radial fuel that flows back to the flame holding plate side 23 Vortex 24 Pressure equalizing chamber

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor, Kimito Hitoshi, 1-share, 6473, Fukaya, Ayase-shi, Kanagawa Katsura Seiki Seisakusho Kanagawa factory (56) Reference JP-A-52-6132 (JP, A) Actual Open 50-38837 (JP, U) Open 52-25336 (JP, U) Open 54-164141 (JP, U) Open 59-175844 (JP, U) Open 60-170523 ( JP, U) Actual development Sho 57-120829 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23D 14/22-14/24 F23D 14/74

Claims (5)

(57) [Claims] 1. In a flat frame burner that spreads a flame from a burner tile and blows it out to form a flat flame along an inner wall of a furnace, a radial injection hole is provided at a tip of a fuel pipe for injecting gas fuel in a flow direction of combustion air. 2 or more rows are provided in the column and flame holding plates are provided upstream thereof, and the radial fuel injection holes in the row closer to the flame holding plate are used as the fuel injection holes also serving as pilots, and the minimum number necessary for pilot ignition is provided there. A flat frame burner characterized by injecting an amount of fuel and injecting the remaining fuel from the radial fuel injection holes of another row . 2. The flat frame burner according to claim 1, wherein an axial fuel injection hole is provided at the tip of the fuel pipe. 3. A flat frame burner as claimed in claim 2, characterized in that a uniform pressure chamber turning does not occur in the combustion air inside and through the fuel injection hole and communicating the axial direction of the fuel pipe . 4. The burner tile is composed of a thin material having a high thermal conductivity forming a throat surface and a backup material supporting the throat surface and having a low thermal conductivity and a high heat insulating property. The flat frame burner according to any one of 1 to 3. 5. In a flat frame burner that spreads and ejects flame from an injection hole, an annular recess is provided on the wind box side inner surface of the flange at the rear end of the burner tile, and the annular recess is fitted into the flat recess so as to be substantially tangential along the throat surface. A flat frame burner characterized in that a swirler for swirling air is detachably provided on the.