WO1996014540A1

WO1996014540A1 - Pilot burner and pilot burner gas nozzle utilizing the same

Info

Publication number: WO1996014540A1
Application number: PCT/JP1995/002280
Authority: WO
Inventors: Ryoichi Tanaka; Mamoru Matsuo; Makoto Miyata
Original assignee: Nippon Furnace Kogyo Kabushiki Kaisha
Priority date: 1994-11-08
Filing date: 1995-11-08
Publication date: 1996-05-17
Also published as: JPH08135967A

Abstract

A pilot burner capable of being used as both a pilot burner and a gas nozzle having the piloting function for a main burner, the dimensions of this pilot burner being reduced by omitting an ignition rod. This pilot burner (1) has a conductive outer cylinder (7), and a conductive inner cylinder (9) housed in an electrically insulated state in the outer cylinder (7). A high voltage is applied between the outer cylinder (7) used as an earth electrode and the inner cylinder (9) used as a high-voltage electrode, to produce sparks into spark gaps (39) in the vicinity of air ejection ports (37) and ignite a diffused mixed gas occurring in the vicinity of the ejection ports (37), whereby pilot flames (45) are generated. A diffused mixed gas occurring on the further downstream side is burnt with these pilot flames (45).

Description

Specified damage, 'Ilot burner and pilot burner combined gas nozzle using it

The present invention relates to a gas combustion device that can be applied both as a pilot gas parner and as a gas nozzle constituting a main burner. Background art

As shown in Fig. 5, the conventional pilot gas parner is installed in the premixing space 105 in the air passage 103 through which a sufficient amount of combustion air flows to form a pilot flame. The ignition rod 107 is extended to reach the spark by applying high pressure between the ignition rod 107 and the outer cylinder 115 using a high-voltage power supply (not shown). Is provided. Part of the fuel gas flowing through the fuel passage 1 11 in the inner cylinder 1 09 is located above the point where sparks fly between the ignition rod 107 and the outer cylinder 1 15. The premixed gas is injected into the premixing space 105 in the air passage 103 through the communication hole 113 provided on the flow side, and is mixed with the combustion air to be a combustible premixed gas. This premixed gas ignites in the spark and generates a pilot flame. On the other hand, the fuel gas ejected from the fuel passage 111 toward the main parner (not shown) is diffused and mixed with the combustion air ejected from the air passage 103 toward the main parner to become a diffusion mixed gas. A pilot flame ignites this diffusion-mixed gas, producing a bi-flame flame 117.

However, in the conventional pilot gas parner 101, the ignition rod 107 supported by an insulator separately from the outer cylinder 115 and the inner cylinder 109 is formed by the outer cylinder 111. The provision of the air passage 103 between the inner cylinder 109 and the inner cylinder 109 complicates the structure and makes it impossible to make the outer cylinder 115 smaller, making the pilot burner smaller. There was a problem that it was difficult to convert. In addition, in this pilot gas parlor 101, the amount of heat received from the furnace cannot be reduced due to the difficulty in downsizing. In addition, since the load rod 107 is arranged inside the air passage 103, the passage area of the air passage 103 becomes large and the inside of the air passage 103 becomes large. Therefore, the cooling effect of the combustion air cannot be expected much. For this reason, the inner cylinder and the ignition port 107 may be deformed by heat and their relative position may be deviated, and if deformed, the ignition of the combustible mixed gas becomes unstable. There were also problems. In particular, the ignition rod 107 is left in a flame without a cooling body, so it is easily deformed or oxidized at a high temperature. Also, in order to compensate for the lack of rigidity of the ignition rod 107, an intermediate support is required, which complicates the structure and obstructs the flame monitoring field of view.

Furthermore, since the conventional main burner needs to be provided with separate pie mouth burners for ignition and flame holding, the installation work to the furnace is troublesome and the furnace installation is difficult. There were also problems such as equipment being expensive. Disclosure of the invention

An object of the present invention is to provide a pilot burner that can reduce the size by omitting an ignition rod for ignition. Another object of the present invention is to provide a gas burner that also serves as a pilot burner that can independently constitute a main burner without requiring a separate burner burner.

In order to achieve the above object, a pilot burner of the present invention comprises an inner cylinder of a conductive type for injecting fuel gas, an inner cylinder surrounding the inner cylinder, supporting the inner cylinder with electrical insulation, and connecting the inner cylinder to the inner cylinder. A conductive outer tube for injecting and flowing combustion air through the flow path between the inner tube and the outer tube, with the inner tube being a high-voltage electrode and the outer tube being a ground-side electrode. A high voltage is applied between them, causing a spark to fly near the injection ports of the inner and outer cylinders.

In the case of this by-lot wrench, the inner cylinder is placed between the air-insulated inner cylinder and outer cylinder. When a high voltage is applied with the high voltage electrode and the outer electrode on the ground side, sparks fly near the injection ports of the inner and outer cylinders. In the vicinity of the injection port, a part of the fuel and a part of the combustion air are first-order diffusion mixed and ignited. Further, the fuel and combustion air are diffused and mixed in front of the injection port, and become a combustible diffusion mixed gas. The flame of the primary diffusion gas is burned into this diffusion gas mixture to form a pilot flame.

Therefore, the pilot burner of the present invention can omit the ignition rod conventionally required. For this reason, the structure of the pilot wrench is simplified, the manufacture thereof is facilitated, and the manufacturing cost can be reduced. Moreover, by reducing the size of the outer cylinder, the amount of heat received from the furnace can be reduced, and the flow rate of combustion air can be increased to increase the cooling effect of the cylinder and the outer cylinder. Deformation can be prevented, and the generation of sparks can be stabilized. In addition, the inner cylinder, which also serves as the ignition rod, has higher rigidity than the ignition rod, eliminating the need for an intermediate support, simplifying the structure, and improving flame detection. Does not hinder your view. In addition, even if the inner cylinder, which also serves as the ignition rod, is left in the flame, it is cooled by the fuel gas flowing inside it, so it is not easily deformed or overheated. Therefore, the life is prolonged.

In addition, the pie mouth top wrench of the present invention has a fuel injection port for flame holding, which injects a part of the fuel gas into a flow path between the outer cylinder and the inner cylinder at a position upstream of the injection port in the inner cylinder. Then, a part of the fuel gas is made into a combustible mixture and then injected around the injection port of the inner cylinder, and more preferably, the inner cylinder protrudes into the pilot flame. .

In this case, a part of the fuel gas flowing in the fuel passage is injected from the flame-holding fuel injection port into the air passage between the outer cylinder and the inner cylinder, and is premixed and combusted before reaching the spark point. It is made into a possible premixed gas. On the other hand, since the outer cylinder and the inner cylinder are electrically insulated, if a high-voltage power supply applies a pressure between the outer cylinder and the inner cylinder, the inner cylinder and the outer cylinder near the injection port will become The spark flies and ignites the premixed gas flowing there, forming a pilot flame, or flame for flame holding. In addition, the fuel gas injected from the fuel injection port and the fuel gas injected from the air injection port The generated combustion air is diffused and mixed in front of each injection port to generate a combustible diffusion mixed gas. A pilot flame burns into this diffusion mixture and forms a pilot flame. At the same time, pilots continue to exist with the supply of premixed gas.

Therefore, the flammable mixture always flows to the place where the spark flies, so that the ignition can be reliably performed. In addition, since this flame becomes a flame holding source after ignition, even if the amount of combustion gas is increased, there is no misfire, and the flame holding function is, of course, excellent in the stability of the pilot flame. It can be used as a gas nozzle.

Also, when the inner cylinder is projected into the pilot flame, the inner cylinder can be used as a frame rod because the inner cylinder touches the pilot flame or the pilot flame. The presence or absence of a flame can be detected by the phenomenon.

In this case, since a flame is generated around the inner cylinder, it can be used as a frame rod, and it is possible to connect the inner cylinder to the outer cylinder without installing a separate frame opening. The presence or absence of a frame can be detected simply by applying voltage between them.

In addition, the pilot nozzle gas nozzle also has a conductive inner part for injecting the fuel gas, an inner part surrounding the inner part, supporting the inner part with electrical insulation, and a flow path between the inner part and the inner part. It has a conductive outer surface through which combustion air flows and is injected, and a portion of the fuel gas is provided in the flow path between the outer cylinder and the inner cylinder on the inner side upstream of the injection port. A fuel injection port for flame holding to be injected is formed, and a part of the fuel gas is made into a combustible mixture and then injected around the injection port of the inner cylinder. A high voltage is applied between the inner and outer cylinders as electrodes to form a flame holding flame near the injection port of the inner cylinder.

In this case, a part of the fuel is premixed with the combustion air and injected around the inner cylinder that injects the fuel gas as a combustible premixed gas. There, a spark is blown to ignite the premixed gas to form a flame holding flame, ie, a pilot flame. When increasing the amount of fuel gas injected from the inner cylinder to function as a gas nozzle of the main burner, the fuel gas injected from the fuel injection port in front of the inner cylinder and the fuel gas separately supplied from the outside are used. Next air Are mixed by diffusion to obtain a combustible diffusion mixed gas. There, a flame holding flame burns and burns the main Pana. On the other hand, the flame for flame holding exists and is controlled by the supply of premixed gas.

Therefore, after the spark is ignited by applying a voltage between the inner cylinder and the outer cylinder, the fire is used as a flame nozzle and the gas flow rate is reduced to make the main nozzle a gas nozzle. Can be used. Therefore, it is not necessary to separately install a pie mouth and a wrench, which simplifies the work of attaching to the furnace and reduces the cost of the furnace equipment.

Further, in the pilot nozzle gas nozzle for use in the present invention, the inner cylinder is made to protrude into the flame for flame holding. Also in this pilot burner gas nozzle, by projecting the inner cylinder into the flame holding flame, the inner cylinder itself can function as a frame rod, and the presence or absence of a flame can be detected. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing one embodiment of a pilot burner according to the present invention. Fig. 2 is a front view showing the tip of the pilot gas parner of Fig. 1. FIG. 3 is a longitudinal sectional view showing another embodiment of the pilot burner of the present invention. FIGS. 4A to 4C are schematic diagrams showing an example of the embodiment in which the pie mouth., 'Towner according to the present invention is implemented as a pie mouth and a nozzle. FIG. 5 is a cross-sectional view showing a tip portion of a conventional pilot gas parner. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the configuration of the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an embodiment of a pilot burner according to the present invention. The pilot burner 1 includes an inner cylinder 9 that injects fuel gas, an outer cylinder 7 that supports the inner cylinder 9 and forms a flow path 31 that injects combustion air between the inner cylinder 9 and the inner cylinder 9. Fly high between these sparks It is composed of a pressure source 45 and the like, and is mounted, for example, at a predetermined position on the furnace wall 5 toward a main parner (not shown).

The outer cylinder 7 is formed of a conductive material and is used as a ground electrode. Therefore, the outer cylinder 7 can have a simple insulating support structure, and can be easily achieved by, for example, supporting the furnace wall 5. Therefore, the outer cylinder 7 is inserted into the mounting hole 5a drilled at a predetermined position of the furnace wall 5 made of refractory heat insulating material until its tip surface is aligned with the inner surface of the furnace wall 5. , It is fixed so that it cannot fall off. A screw hole 13 for screwing a centering guide screw 27 for positioning the inner cylinder 9 at the center of the outer cylinder 7 is provided substantially in the center of the outer cylinder 7 in the axial direction. Further, a base end 7 b of the outer cylinder 7 projects from the furnace wall 5 and is disposed outside the furnace 3.

A gas port 15 for introducing gaseous fuel, an air port 17 for introducing combustion air, and a Bragg insertion hole 19 are provided at a base end 7 b of the outer cylinder 7. The gas port 15 is a T-shaped hole penetrating through the center of the outer cylinder 7 in the pipe axis direction. The inner cylinder 9 is connected to one end, and the flame detector 21 is attached to the other end. It is provided to detect whether or not a pilot flame 47 is generated. The means for detecting the presence or absence of the pilot flame 47 is not limited to the flame detector 21; instead, a flame window is provided instead of the flame detector 21. The operator may directly check whether or not the pilot flame 47 is generated.

Inner wall 9 is formed of a conductive material and is used as a high-voltage electrode. The inner cylinder 9 is accommodated in the outer cylinder 7 while being arranged concentrically. The inner cylinder 9 is fitted into the gas port 15 of the proximal end 7 b of the outer sleeve 7 via an insulating ring 26 whose base end can provide a sufficient insulating effect. Supported. At this time, the fuel injection port 33 at the tip of the inner cylinder 9 and the air injection □ 37 at the tip of the outer cylinder 7 are provided at the same position. In addition, a large diameter portion 9a is provided at a position upstream of the fuel injection port 33 at the tip of the inner cylinder 9. The surface near the end of the expanding part 9 a is a tapered surface that shrinks as it approaches the end of the inner cylinder 9. On this tape surface A plurality of flame-holding fuel injection holes 23 are drilled at a plurality of locations along the circumferential direction, and a part of the fuel flowing through the inner cylinder 9 is used to flow the combustion air between the outer cylinder 7 and the inner cylinder 9. It is set up to inject into. An insulating ring 25 is fitted in the center of the inner wall 9 so as not to fall off. Then, a centering guide screw 27 protruding from the outer ring 7 is pressed against the insulating ring 25 to support the inner ring 9 so that the inner ring 9 is disposed substantially at the center of the outer cylinder 7. . Here, it is preferable that the centering guide screws 27 are provided at three points at equal intervals, but the present invention is not particularly limited to this, and more or less than two points or one point at the center is provided. The cylinder 9 may be supported. That is, the inner cylinder 9 is fixed to the outer cylinder 7 while being electrically insulated through the insulating rings 25 and 26. The insulating rings 25 and 26 are made of, for example, insulating rubber or insulator.

In this pilot gas parner 1, the inner part 9 forms a fuel passage 29 and the outer cylinder 7 forms an air passage 31, and are connected to the gas port 15 and the air port 17, respectively. A fuel gas supply system (not shown) is connected to the gas port 15, and a sufficient amount of fuel gas for forming a pilot flame is supplied.

Further, a combustion air supply system (not shown) is connected to the air port 17 so that a sufficient amount of combustion air for forming a pilot flame is supplied. The vicinity of the exit of the air passage 31 extends along the tapered surface of the enlarged part 9a, and forms a premixed space 35. Therefore, each flame-holding fuel injection hole 23 formed in the tapered surface of the enlarged part 9a opens toward the premixed table space 35. Here, in the pilot gas burner 1, since the inner cylinder 9 serves both as an ignition rod and a frame rod, a space between the outer cylinder 7 and the inner cylinder 9 is provided. The space of the furnace can be set relatively small, and the amount of heat received from the furnace can be reduced by making the outer cylinder 7 narrower by that much, and the cooling effect can be increased by increasing the flow rate of combustion air.

The ring-shaped member 11 is formed of a conductive material, and is fitted and fixed to a distal end portion of the outer cylinder 7, that is, an outlet portion of the air passage 31. As shown in FIG. 2, the outer peripheral surface of the ring-shaped member 11 has grooves recessed at predetermined intervals in the circumferential direction. But Thus, a plurality of holes 37,..., 37 along the circumferential direction are formed between the outer case 7 and the ring-shaped member 11. These holes 3 7,..., 3 7 serve as air injection ports. Further, a slight gap 39 is formed between the inner cylinder 9 and the ring-shaped member 11, and the combustible mixture formed in the premixing space 35 is injected from the gap 39 and the gap 3 is formed. The spark is skipped in nine parts. The shape and the like of the air injection port 37 are not particularly limited to those shown in FIG.

A spark plug 41 is fitted into the plug insertion hole 19 of the outer cylinder 7, screwed and fixed, and pressed against the inner wall 9. The spark plug 41 is electrically connected to the low-voltage power supply 43, and the inner cylinder 9 is used as a high-pressure battery to blow a spark between the inner cylinder 9 and the outer cylinder 7. I'm doing it. Here, the insulation of the inner cylinder 9 is firmly secured by the insulating rings 25, 26. In addition, a simple insulating structure is sufficient for the outer cylinder 7 serving as the ground side electrode. The outer cylinder 7 does not need to be entirely formed of a conductive material, but is formed of a conductive material only at the portion where sparks need to be blown, for example, only the tip portion, and the other portions are formed of a ceramic material. A non-conductive material such as metal may be used.

This pilot gas burner 1 forms a pilot flame 47 as follows and ignites the main burner.

Combustion air is supplied into the air port 17 from the combustion air supply system, and fuel gas is supplied into the gas boat 15 from the fuel gas supply system. The combustion air that has flowed into the air passage 31 from the air port 17 flows toward each of the air outlets 37 and the spark gap 39. Further, the fuel gas supplied into the gas port 15 flows through the fuel passage 29 toward the fuel gas ejection port 33. At this time, a part of the fuel gas flows from the flame-injecting fuel injection □ 23 into the premixing space 35 in the air passage 31, where it can mix with the combustion air and burn. It becomes a premixed gas. This premixed gas flows toward the spark gear 39.

On the other hand, the combustion gas injected from the fuel injection holes 33 toward the main parner is diffused and mixed with the combustion air injected from the air injection holes 37, ..., 37 toward the main parner. , It becomes a combustible diffusion mixed gas.

When a high voltage is applied between the electrodes of the spark plug 41 from the high-voltage power supply 43, in other words, between the outer electrode 7 and the inner electrode 9, a discharge occurs at the position of the spark gap 39. Then sparks fly. As described above, the premixed gas that can be burned flows into the spark gear 39, and the spark generated by the spark ignites the premixed gas, generating a flame 45 for pilot and flame holding, which is flame holding. Acts as a source. Following this, the pilot flame 45 burns into the diffusion gas mixture, generating a pilot flame 47. Pilot flame 47 ignites the main wrench.

On the other hand, the pilot flame 45 receives the supply of the premix gas formed in the premix space 35 and burns. Therefore, the pilot gas parner 1 has a so-called flame holding function.

The combustion air supply system supplies relatively low temperature combustion air into the air passage 31. The passage area of the air passage 31 is set to be smaller than that of the conventional pilot gas parner 101 shown in FIG. Therefore, the flow of the cold combustion air flowing in the air passage 31 is increased, and the pilot gas parner 1 is efficiently cooled.

Further, since the pilot gas parner 1 skips the spark in the gap 39 between the inner cylinder 9 and the outer ring 7, the entire pilot gas parner 1 is thinner by the ignition rod. Become. Therefore, the amount of heat received from furnace 3 that affects pilot gas burner 1 is reduced.

FIG. 3 shows another embodiment. This embodiment is an example of a pilot wrench in which premixing is not performed to obtain a flammable mixture that forms a flame for flame holding. In this pilot burner, the tip of the inner cylinder 9 is projected from the tip of the outer cylinder 7 to inject fuel downstream of the air injection port 37. A sub-injection port 24 for injecting a part of the fuel toward the flow of combustion air is provided on a peripheral surface of the inner cylinder 9 near the air injection port 37. The main injection port 33, which injects most of the fuel, opens at the end of the inner cylinder 9 almost parallel to the air injection port 37, and is located downstream of the combustion air injection position. It is provided to inject most of the fuel. A gap 39 suitable for blowing a spark is formed between the inner wall 9 and the outer wall 7. Insulating ring at the end of inner cylinder 9

It is supported by a ring member 11 'fixed to the outer cylinder 7 side via 25'. Therefore, a constant gap 39 suitable for flying the spark is stably secured between the ring member 11 ′ forming a part of the outer ring 7 and the inner ring 9. In this embodiment, the inner cylinder 9 is bent into an L-shape and is fixed to the side wall of the outer cylinder 7 via an insulating ring 26 ′ in order to facilitate the pipe structure. An optical flame detector 21 is attached to the base end of the outer cylinder 7, and a frame rod amplifier 44 is electrically connected to the inner cylinder 9 via a spark plug 41. . Further, a cap 46 that forms a mixing chamber for restraining the injected air and fuel from diffusing to the surroundings is fixed to the tip of the outer cylinder 7.

According to the pilot burner configured as described above, a part of the fuel injected from the auxiliary fuel injection port 24 and the air injected from the injection port 37 near the combustion air injection port 37 Is partially diffusion mixed. Sparks fly there, igniting and forming a pilot flame 45. Further, the fuel and the combustion air are supplied in front of the injection ports 37, 33, that is, the injection ports.

Diffusion mixed at a position distant from 37, 33 to become a combustible diffusion mixed gas. The flame and seed flame 45 of the primary diffusion mixed gas are burned into the diffusion mixed gas, and a pilot flame 47 is formed. Also, at this time, since the tip of the inner cylinder 9 exists in the primary diffusion flame 45, when a voltage is applied between the cylinder 9 and the outer cylinder 7, current flows when there is a flame, and when there is no flame. Shows a flame conduction phenomenon in which no current flows. That is, the inner cylinder 9 functions as a frame rod.

The above embodiment is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described case, an example in which the present invention is applied to the pie mouth gas burner 1 is shown, but the present invention is not limited to this, and as shown in FIGS. 4A to 4C, the inside of the air throat 50 is provided. Or installed near and in parallel with the air slot 50, and It may be applied to nozzles. In the example of FIG. 4A, the pilot gas burner 1 is arranged at the center of the air throat 50, and in the example of FIG. 4B, the pilot gas burner 1 is arranged at a position eccentric from the center of the air throat 50. In the example shown in Fig. 4C, the pie port gas burner 1 is arranged as the air throat 50 so that fuel is injected directly into the furnace 3 from outside the air throat 50 and near the air throat 50. Have been. Note that reference numeral 51 in the figure denotes a wind box. In these cases, the basic configuration is essentially the one represented in Fig. 1 or Fig. 3, except that the amount of gas fuel injected differs between when the pilot is ignited and when the main burner burns. The pilot flame 45 generated in the spark gap 39 functions as a flame holding flame, making it possible to supply gaseous fuel. The secondary air supplied separately from the outside and the inner cylinder 7 remain unchanged. The combustible diffusion mixed gas generated by diffusion mixing with the fuel gas injected from the fuel is burned. That is, according to this gas nozzle, when the amount of fuel is as small as that for a pilot, the pilot flame functions as an ignition flame and is formed by the fuel injected from the injection port 33. The generated flame 47 becomes a pilot flame, but as the amount of injected fuel increases, the amount of fuel flowing out of the injection port 23 or 24 increases, and the pilot flame 45 becomes a flame holding flame. The main flame is formed by the fuel injected from the injection port 33 and the secondary air flowing around the outer circumference 7. Therefore, this gas nozzle will also have the function of a pilot gas burner, eliminating the need to provide a separate pilot gas burner to ignite the main burner.

Claims

The scope of the claims

1. A conductive inner cylinder that injects fuel gas, and a conductive inner pipe that surrounds the inner pipe, supports the inner pipe with electrical insulation, and injects combustion air through a flow path between the inner pipe and the inner pipe. A high voltage is applied between the inner cylinder and the outer cylinder by using the inner cylinder as a high-voltage electrode and the outer cylinder as a ground-side electrode, and applying a high voltage between the inner cylinder and the outer cylinder. A pi-mouth toppana that features a spark near the injection port.

2. The inner cylinder is provided with a flame-holding fuel injection port for injecting a part of the fuel gas in a flow path between the outer cylinder and the inner cylinder upstream of the injection port, and a part of the fuel gas is formed. 2. The fuel tank according to claim 1, wherein the fuel is injected as a combustible mixture around the injection port of the inner cylinder.

3. The pilot burner according to claim 1 or 2, wherein the inner cylinder is projected into a pilot flame.

4. A conductive inner cylinder that injects fuel gas, and a conductive inner cylinder that surrounds the inner wall, supports the inner cylinder with electrical insulation, and injects combustion air by flowing combustion air through a flow path between the inner cylinder and the inner cylinder. A fuel injection port for flame holding, which injects a part of the fuel gas into a flow path between the outer cylinder and the inner cylinder at an upstream side of the injection port, the fuel injection port having an outer cylinder; A part of the fuel gas is turned into a combustible mixture and then injected around the injection port of the inner cylinder, while the inner cylinder is used as a high-voltage electrode and the outer cylinder is used as a ground electrode, and the inner cylinder and the outer cylinder A high-voltage is applied between the inner cylinder and a flame for holding a flame near the injection port of the inner cylinder.

5. The gas nozzle as claimed in claim ^4, wherein the inner cylinder is protruded into a flame holding flame.