Burner nozzle

Abstract

To provide a burner nozzle that has a pilot burner capable of forming stable pilot flame without a risk of flashback, and can ensure a sufficient flow rate of main fuel even for a gas type with a small combustion capacity.SOLUTION: A burner nozzle 1 according to the present invention has: a main fuel flow path 8 that is provided in a gun head 9 and supplies main fuel, which is fuel for a main burner, to the main burner; a pilot fuel flow path 6 that supplies pilot fuel, which is fuel for a pilot burner, separately from the main fuel; and a pilot air flow path 7 that supplies pilot air, which is air for the pilot burner. The pilot burner having the pilot fuel flow path and a pilot air flow path, has a pilot burner function independent of the main burner.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a burner nozzle. [Background technology]

[0002] A conventional burner nozzle with a pilot burner function is one in which an intermediate pipe through which primary air flows is installed inside an outer pipe through which fuel gas for the main burner flows, and an inner pipe through which premixed gas, the fuel gas for the pilot burner, flows, is installed inside this intermediate pipe (see Patent Document 1).In this burner nozzle, a pilot flame is formed in the center of the burner by the premixed gas, and the primary air ejected from the intermediate pipe stably burns the pilot flame.

[0003] Another proposed burner nozzle has a triple-pipe structure in which a main fuel discharge pipe, a pilot fuel discharge pipe, and a pilot air discharge pipe are arranged in that order from the inside to the outside, and the flow rate detection orifices and pressure plugs provided in each flow path are integrated into the gun head (see Patent Document 2).This burner nozzle not only makes the fuel discharge structure more compact, but also achieves stable combustion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-117612 [Patent Document 2] Japanese Patent Application Publication No. 9-310820 Summary of the Invention [Problem to be solved by the invention]

[0005] In the burner nozzle described in Patent Document 1, a premixed gas is used for the pilot burner, so there is a risk of backfire occurring.

[0006] Furthermore, in the burner nozzle described in Patent Document 2, the innermost pipe is used as a flow path for fuel gas for the main burner, which creates the problem that a sufficient main fuel flow rate cannot be ensured when a gas type with a small combustion capacity is used as fuel for the main burner.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a burner nozzle that is capable of forming a stable pilot flame without the risk of flashback and that can ensure a sufficient flow rate of main fuel even for gas types with small combustion capacity. [Means for solving the problem]

[0008] The present invention, which solves the above problems, is as follows. [1] In a burner nozzle that supplies fuel to a burner, A burner nozzle characterized in that a gun head is formed with a main fuel passage for supplying main fuel, which is fuel for a main burner, to the main burner, a pilot fuel passage for supplying pilot fuel, which is fuel for a pilot burner separate from the main fuel, and a pilot air passage for supplying pilot air, which is air for the pilot burner, and the pilot burner having the pilot fuel passage and pilot air passage has a pilot burner function independent of the main burner.

[0009] [2] The gun head has a triple pipe structure consisting of a pilot fuel discharge pipe, a pilot air discharge pipe arranged outside the pilot fuel discharge pipe, and a main fuel discharge pipe arranged outside the pilot air discharge pipe, The burner nozzle according to [1] above, wherein the pilot fuel flow path is provided inside the pilot fuel discharge pipe, the pilot air flow path is provided between the pilot fuel discharge pipe and the pilot air discharge pipe, and the main fuel flow path is provided between the pilot air discharge pipe and the main fuel discharge pipe, and the pilot fuel and the pilot air are mixed near the main fuel discharge port of the main fuel discharge pipe to cause diffusion combustion.

[0010] [3] A burner nozzle according to [2], further comprising a nozzle cap at the tip of the pilot fuel discharge pipe, the nozzle cap having a plurality of flow paths for dispersing the pilot fuel radially outward from the center of the nozzle, the nozzle cap discharging the pilot fuel radially outward upstream of the main fuel discharge port, and the pilot fuel and the pilot air being mixed together.

[0011] [4] The burner nozzle according to any one of [1] to [3], which has a main fuel discharge portion protruding downstream of the burner nozzle inside the tip of the main fuel discharge pipe, and further has a flame stabilizing hood extending downstream from the main fuel discharge portion at the tip of the main fuel discharge pipe.

[0012] [5] The burner nozzle described in [4], wherein the tip of the nozzle cap has a structure that expands radially outward toward the downstream side of the burner nozzle, forming a gap between the nozzle cap and the main fuel discharge section, and generating a spark in the gap.

[0013] [6] A burner nozzle according to any one of the above [1] to [5], wherein a conductive inner tube in which the pilot air discharge pipe and the pilot fuel discharge pipe are integrated by the nozzle cap, and a main fuel discharge portion of the main fuel discharge pipe are supported by a heat-resistant electrical insulating material, and the inner tube and the main fuel discharge pipe are electrically insulated by a resin material upstream of the electrical insulating material.

[0014] [7] A burner nozzle according to any one of [1] to [6], wherein the inner tube is a high-voltage electrode, the main fuel discharge pipe is a ground electrode, and a high voltage is applied between the inner tube and the main fuel discharge pipe to generate a spark at a mixture of the pilot fuel and the pilot air, thereby forming a pilot flame.

[0015] [8] A burner nozzle according to any one of [1] to [7], wherein the gun head is provided with at least one sight hole for visually monitoring the ignition state of the pilot flame and at least one ultra vision capable of detecting the pilot flame, and is configured to enable both visual and sensor-based monitoring of the pilot flame state. [Effects of the Invention]

[0016] According to the present invention, a pilot burner capable of forming a stable pilot flame without the risk of backfire is provided, and a sufficient flow rate of the main fuel can be ensured even for gas types with small combustion capacity. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing a preferred example of a burner nozzle according to the present invention; [Figure 2] FIG. 2 is a diagram showing a detailed structure of the tip of the burner nozzle shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A burner nozzle according to the present invention has a gun head formed with a main fuel passage for supplying main fuel, which is fuel for the main burner, to the main burner, a pilot fuel passage for supplying pilot fuel, which is fuel for the pilot burner separate from the main fuel, and a pilot air passage for supplying pilot air, which is air for the pilot burner. The pilot burner, which has the pilot fuel passage and the pilot air passage, has a pilot burner function independent of the main burner. In the present invention, "the pilot burner has a pilot burner function independent of the main burner" means that the pilot burner and the main burner have burner functions independent of each other, and the ignition state of only the pilot burner can be maintained even when the main burner is in an extinguished state.

[0019] Figure 1 shows a preferred example of a burner nozzle according to the present invention. Figure 2 shows the detailed structure of the tip 14 of the burner nozzle 1 shown in Figure 1. The burner nozzle 1 shown in Figure 1 has a triple pipe structure in the gun head 9, which is made up of a pilot fuel discharge pipe 2, a pilot air discharge pipe 3 arranged outside the pilot fuel discharge pipe 2, and a main fuel discharge pipe 5 arranged outside the pilot air discharge pipe 3.

[0020] In the triple-pipe structure, a pilot fuel flow path 6 that supplies fuel for the pilot burner (pilot fuel) is provided inside the pilot fuel discharge pipe 2. A pilot air flow path 7 that supplies air for the pilot burner (pilot air) is provided between the pilot fuel discharge pipe 2 and the pilot air discharge pipe 3. A main fuel flow path 8 that supplies fuel for the main burner (main fuel) is provided between the pilot air discharge pipe 3 and the main fuel discharge pipe 5. As shown in FIG. 2 , the pilot fuel and pilot air are mixed near a main fuel discharge port 17 of the main fuel discharge pipe 5, and diffusion combustion occurs.

[0021] The gun head 9 is also provided with at least one sight hole 10 for visually monitoring the ignition state of the pilot flame and one Ultravision mounting port 11 for mounting an Ultravision device capable of detecting the pilot flame.The gun head 9 is also provided with an ignition plug mounting port 13 for connecting an ignition plug (not shown) to the pilot air discharge pipe 3.

[0022] In this way, in the burner nozzle 1, the pilot air flow path 7 and the pilot fuel flow path 6 are separately provided by the pilot air discharge pipe 3 and the pilot fuel discharge pipe 2, and the pilot fuel and pilot air are mixed near the main fuel discharge port 17 of the main fuel discharge pipe 5, thereby achieving diffusion combustion in the pilot burner. As a result, there is no risk of flashback due to ignition delay, etc., and highly safe pilot combustion can be achieved.

[0023] Furthermore, by making the outermost flow passage of the triple-pipe structure the main fuel flow passage 8, it becomes easy to ensure the flow passage area for the main fuel, and even when a gas type with a small combustion capacity is used as the main fuel, a sufficient flow rate can be ensured, thereby increasing the combustion capacity of the burner.

[0024] Referring to FIG. 2, a nozzle cap 19 is attached to the tip 2a of the pilot fuel discharge pipe 2, and the nozzle cap 19 has an umbrella structure with a plurality of radial flow paths 6a that disperse the pilot fuel radially from the center of the nozzle outward in the radial direction.

[0025] As described above, in burner nozzle 1, pilot fuel passage 6 is provided in the innermost layer, and pilot air passage 7 is provided outside of that, but with such a nozzle structure, there is a risk that pilot fuel and pilot air will not mix well at nozzle tip 14, resulting in insufficient ignition ability and flame stability. In this regard, by providing multiple radial passages 6a extending radially outward from the nozzle center and dispersing pilot fuel to the radially outer side of pilot fuel discharge pipe 2 upstream of main fuel discharge port 17, it is possible to improve the mixing ability of pilot fuel and pilot air at pilot fuel discharge port 20, and to form a good radial pilot flame downstream thereof.

[0026] The nozzle cap 19 is detachable, and by replacing the nozzle cap 19, the flow rate and discharge angle of the pilot fuel can be changed, thereby making it possible to adjust the pilot flame.

[0027] As described above, the nozzle cap 19 has an umbrella structure in which the pilot fuel flow path 6 expands radially outward toward the downstream side, and the pilot flame is formed radially from the nozzle center. This makes it possible to install the sight hole 10 for visually observing the flame and the Ultra Vision for flame detection at a position shifted radially outward from the nozzle center. The sight hole 10 and the Ultra Vision mounting port 11 communicate with the main fuel flow path 8, and by installing the Ultra Vision in the Ultra Vision mounting port 11, the pilot flame status can be monitored both visually and by a sensor.

[0028] Nozzle cap 19 is also made of a conductive material and is in contact with pilot air discharge pipe 3 at a position not shown in Fig. 2. This electrically integrates pilot fuel discharge pipe 2 and pilot air discharge pipe 3 to form conductive inner cylinder 4. Main fuel discharge portion 16 of main fuel discharge pipe 5 and pilot air discharge pipe 3 are supported at the tip of the burner by heat-resistant electrical insulating material 15, and are electrically insulated upstream of electrical insulating material 15, for example, via resin material 12 within gun head 9.

[0029] In the above-described structure, an ignition plug (not shown) is brought into contact with the pilot air discharge pipe 3, making the inner tube 4 a high-voltage electrode, while the main fuel discharge pipe 5 is made a ground electrode, and by applying a high voltage (for example, 10,000 to 30,000 V) between the inner tube 4 and the main fuel discharge pipe 5, a spark is generated in the spark section 21 to form a pilot flame.

[0030] A main fuel discharge part 16 is provided inside the tip of the main fuel discharge pipe 5, protruding downstream of the burner nozzle 1, and the main fuel is discharged from a main fuel discharge port 17. Furthermore, a flame stabilizing hood 18 is provided extending downstream of the main fuel discharge part 16, making it possible to keep the flame of the main burner stable.

[0031] The tip of the nozzle cap 19 has a structure that expands radially outward toward the downstream side of the burner nozzle 1, and it is preferable to form a gap between the main fuel discharge portion 16, i.e., between the inner cylinder 4 and the flame stabilizing hood 18, at the position where the mixture of pilot fuel and air is discharged, and to generate a spark in this gap. In other words, it is preferable to make the gap a spark portion 21. This makes it possible to generate a spark at the discharge portion of the mixture of pilot fuel and pilot air, thereby igniting the pilot burner.

[0032] The operation of the burner nozzle 1 will now be described. First, pilot fuel is supplied from a pilot fuel supply source (not shown) to the pilot fuel passage 6, and pilot air is supplied from a pilot air supply source (not shown). Next, a high voltage (e.g., 10,000 V) is applied between the spark plug (not shown) (pilot air discharge pipe 3) attached to the spark plug mounting port 13 and the main fuel discharge pipe 5 to generate a spark and ignite the pilot burner. Once a pilot flame is confirmed by the sight hole 10 and the ultrasound vision attached to the ultrasound vision mounting port 11, main fuel is supplied from the main fuel supply source (not shown) to the main fuel passage 8, and main air is supplied to the main fuel from a main air supply source (not shown) that supplies main air for the main burner. In this way, the main burner can be ignited. [Industrial Applicability]

[0033] According to the present invention, a pilot burner capable of forming a stable pilot flame without the risk of backfire is provided, and a sufficient flow rate of the main fuel can be ensured even for gas types with small combustion capacity. [Explanation of symbols]

[0034] 1 burner nozzle 2 Pilot fuel discharge pipe 2a Tip 3 Pilot air discharge pipe 4 Inner cylinder 5 Main fuel discharge pipe 6 Pilot fuel passage 6a Radial flow path 7 Pilot air passage 8 Main fuel passage 9 Gunhead 10 Sight Hall 11 Ultra Vision mounting port 12 Resin material 13 Spark plug mounting hole 14 Tip 15 Electrical insulation materials 16 Main fuel outlet 17 Main fuel outlet 18 Flame-holding hood 19 Nozzle cap 20 Pilot fuel outlet 21 Spark Club

Claims

1. In a burner nozzle that supplies fuel to a burner, a gun head formed with a main fuel passage for supplying main fuel, which is fuel for a main burner, to the main burner; a pilot fuel passage for supplying pilot fuel, which is fuel for a pilot burner, separate from the main fuel; and a pilot air passage for supplying pilot air, which is air for the pilot burner; and the pilot burner having the pilot fuel passage and the pilot air passage has a pilot burner function independent of the main burner, the gun head has a triple pipe structure consisting of a pilot fuel discharge pipe, a pilot air discharge pipe disposed outside the pilot fuel discharge pipe, and a main fuel discharge pipe disposed outside the pilot air discharge pipe, the pilot fuel flow path is provided inside the pilot fuel discharge pipe, the pilot air flow path is provided between the pilot fuel discharge pipe and the pilot air discharge pipe, and the main fuel flow path is provided between the pilot air discharge pipe and the main fuel discharge pipe, and the pilot fuel and the pilot air are mixed near a main fuel discharge port of the main fuel discharge pipe and are combusted by diffusion combustion, a main fuel discharge portion protruding downstream of the burner nozzle from inside the tip of the main fuel discharge pipe, and a flame stabilizing hood extending downstream from the main fuel discharge portion at the tip of the main fuel discharge pipe.

2. 2. The burner nozzle according to claim 1, further comprising a nozzle cap at a tip end of the pilot fuel discharge pipe, the nozzle cap having a plurality of flow passages for dispersing the pilot fuel radially outward from a center of the nozzle, the nozzle cap discharging the pilot fuel radially outward on a side upstream of the main fuel discharge port, and mixing the pilot fuel with the pilot air.

3. 3. The burner nozzle according to claim 2, wherein the tip of the nozzle cap has a structure that expands radially outward toward the downstream side of the burner nozzle, forming a gap between the tip of the nozzle cap and the main fuel discharge portion, and generating a spark in the gap.

4. 4. The burner nozzle according to claim 2, wherein a conductive inner tube in which the pilot air discharge pipe and the pilot fuel discharge pipe are integrated by the nozzle cap, and a main fuel discharge portion of the main fuel discharge pipe are supported by a heat-resistant electrical insulating material, and the inner tube and the main fuel discharge pipe are electrically insulated from each other by a resin material upstream of the electrical insulating material.

5. 5. The burner nozzle according to claim 4, wherein a high voltage is applied between the inner cylinder and the main fuel discharge pipe, with the inner cylinder serving as a high-voltage electrode and the main fuel discharge pipe serving as a ground electrode, to generate a spark at a mixture of the pilot fuel and the pilot air, thereby forming a pilot flame.

6. 4. The burner nozzle according to claim 1, wherein the gun head is provided with at least one sight hole for visually monitoring the ignition state of the pilot flame and at least one ultra vision capable of detecting the pilot flame, and is configured to enable both visual and sensor-based monitoring of the pilot flame state.

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