JP5814647B2 - Burner spark igniter - Google Patents

Description

The technique disclosed herein relates to a spark ignition device for a burner, and more particularly to a spark ignition device for a burner in an underwater combustion type vaporizer in an environment where condensation is likely to occur and an ignition error is likely to occur due to poor insulation resulting therefrom.

  As one of low temperature liquefied gas vaporizers such as liquefied natural gas, an underwater combustion type vaporizer (Submerged Combustion Vaporizer) is known (see, for example, Patent Document 1). Such an underwater combustion type vaporizer is also used as an emergency for covering a rapid increase in demand, and requires rapid start-up. On the other hand, since the underwater combustion burner used for an underwater combustion type vaporizer is arrange | positioned at the downcommer immersed in the water tank, internal humidity is very high. For this reason, when the underwater combustion type vaporizer is stopped, condensation is likely to occur in the spark ignition device of the underwater combustion burner. In addition, the spark ignition device referred to here is more precisely because the main burner of the underwater combustion burner has an extremely large heat capacity, and therefore the underwater combustion burner generally includes a pilot burner in addition to the main burner. A spark ignition device for igniting a pilot burner. Condensation causes poor insulation of the spark ignition device and causes an ignition error. Therefore, in such an underwater combustion type vaporizer, measures are taken to prevent condensation by constantly supplying dry instrumented air to the spark ignition device of the underwater combustion burner.

  Further, for example, Patent Document 2 describes, as a technique for preventing condensation of the ignition device provided in the gas cutting torch, that the ignition device is disposed inside the gas cutting torch that becomes a high temperature during use. Yes. Thereby, water is sprayed on the cut object to be cut by the cutting torch, but the water is prevented from adhering to the ignition device and causing condensation.

  Further, for example, in Patent Document 3, in an ignition device for an oil burner of a hot air heater, a convex portion that promotes the discharge of the attached condensed water is formed on the electrode insulator of the connection portion that connects the high voltage cable and the electrode. The technology is described.

Japanese Utility Model Publication No. 5-75599 JP-A-9-285863 JP 2002-333134 A

  As described above, in the spark ignition device of the underwater combustion burner in the underwater combustion type vaporizer, the inventor of the present application has taken measures to prevent condensation by always supplying dry instrument air. When the temperature is extremely low, etc., it was confirmed that even if such measures were taken, an ignition error occurred, and the start-up time of the underwater combustion burner, and consequently the start-up time of the underwater combustion type vaporizer, could be lengthened. .

  The technology disclosed herein has been made in view of such points, and an object thereof is to provide a burner spark ignition device that prevents an ignition mistake.

As a result of examination by the inventors of the present application, it has been found that the amount of condensation is large at a low outside air temperature, resulting in an insulation failure at a specific position of the spark ignition device. Specifically, the pilot burner to be studied by the present inventor is arranged so as to extend in a substantially vertical direction and has a burner body provided with a burner tip at the lower end thereof, and substantially parallel to the burner body. The spark rod is disposed so as to extend in the vertical direction, and the tip of the spark rod is disposed close to the burner tip, and the intermediate portion excluding the tip of the spark rod is accommodated, and the spark rod is disposed at the lower end thereof. And a rod holding tube in which an insulator for supporting the intermediate portion in an insulated state is inserted. Here, the lower end surface of the insulator is exposed downward through the lower end opening of the rod holding tube, and an insertion hole through which the spark rod passes is formed in the insulator. For this reason, this insertion hole is opened in the lower end surface of the insulator exposed downward.

  In the pilot burner of this configuration, dry instrumentation air is constantly supplied from the upper end into the rod holding pipe, and the instrumentation air is configured to be discharged out of the rod holding pipe through the insertion hole of the insulator. Yes. Normally, the instrument rod air dries the surroundings of the spark rod, so that the insulation state is maintained and no ignition errors occur.However, when the outside air temperature is extremely low, a large amount of condensation is formed on the outer peripheral surface of the rod holding tube. As a result of the adhesion, the condensation moves to the lower end of the rod holding tube arranged so as to extend in the vertical direction by gravity, and a large amount of water accumulates at the lower end of the rod holding tube.

  Here, since the lower end surface of the insulator exposed downward from the lower end opening of the rod holding tube was a flat surface in the past, the water accumulated at the lower end portion of the rod holding tube also enters the flat lower end surface of the insulator. In particular, water adheres to the vicinity of the lower end opening of the insertion hole through which the spark rod is inserted, and this causes a poor insulation of the spark rod in this portion.

  Therefore, even if a large amount of condensation adheres to the outer peripheral surface of the rod holding tube and water accumulates at the lower end of the rod holding tube, the inventor of the present application is near the lower end opening of the insertion hole through which the spark rod is disposed. Took measures to prevent water from adhering to keep the spark rod in good insulation and avoid ignition mistakes.

Specifically, a spark ignition device for a burner in an underwater combustion type vaporizer disclosed herein includes a burner body provided with a fuel gas supply port at its base end and a burner tip at its tip, and a vertical direction And a rod holding tube that accommodates at least an intermediate portion excluding the tip of the spark rod, and the rod. And an insulator inserted in a lower end portion of the holding tube and supporting an intermediate portion of the spark rod in an insulated state.

  And, in the insulator, an insertion hole through which the spark rod passes is formed, and the insertion hole opens to a lower end surface of the insulator exposed downward through a lower end opening of the rod holding tube, The rod holding tube is disposed so as to surround the outer periphery of the lower end opening of the insertion hole, is continuous with the outer peripheral surface of the rod holding tube, and is lower than the height position of the lower end opening of the insertion hole. An extending portion extending downward to the position is provided.

  Here, “arranged so as to extend in the vertical direction” means that the spark rod and the rod holding tube that accommodates the spark rod are arranged in the vertical direction, and are slightly inclined with respect to the vertical direction. Including both being installed. More specifically, it includes a case where the spark rod and the rod holding tube are disposed at an inclination as long as the condensation attached to the outer peripheral surface of the rod holding tube can move downward due to gravity.

According to this configuration, each of the rod holding pipes that accommodate the spark rod and the intermediate portion thereof is disposed so as to extend in the vertical direction, and as described above, for example, when the outside air temperature is extremely low, When a large amount of dew condensation adheres to the outer peripheral surface, the dew condensation moves down the longitudinal direction of the rod holding tube by gravity, and as a result, a large amount of water accumulates at the lower end of the rod holding tube.

  Here, in the above-described configuration, the rod holding tube is disposed so as to surround the outer periphery of the lower end opening of the insertion hole, is continuous with the outer peripheral surface of the rod holding tube, and has a height of the lower end opening of the insertion hole. An extending portion extending downward to a position below the vertical position is provided. As a result, the water that has moved along the outer peripheral surface of the rod holding tube moves along the extended portion to a lower position. That is, “the extended portion is continuous with the outer peripheral surface of the rod holding tube” means that the water that has traveled along the outer peripheral surface of the rod holding tube is continuous so as to be transmitted to the extended portion. . On the other hand, since the lower end opening of the insertion hole formed in the insulator is located above the lower end of the extending portion, even if water moves downward along the outer peripheral surface of the rod holding tube, It is avoided or suppressed that water adheres to the vicinity of the lower end opening of the insertion hole. As a result, the insulating state of the spark rod can be kept good. That is, it is possible to avoid ignition mistakes and start the burner early even in an environment where a large amount of condensation occurs.

  Here, the lower end surface of the insulator may be formed so as to be inclined downward from the lower end opening of the insertion hole toward the outer peripheral side.

  In this way, as described above, it is possible to prevent water that has moved downward along the outer peripheral surface of the rod holding tube from adhering to the vicinity of the lower end opening of the insertion hole. When dew condensation adheres to the end surface, the lower end surface is inclined downward, so that the dew condensation can be moved to the outer peripheral side of the lower end surface of the insulator by gravity. Therefore, in this configuration, the function of the extending portion and the function of the inclined lower end surface are combined to further prevent water from adhering to the vicinity of the lower end opening of the insertion hole, thereby further improving the insulation state of the spark rod. It becomes possible to maintain better.

As described above, according to the spark ignition device of the burner in the above-described underwater combustion type vaporizer , by providing the extension portion, the water that has moved downward along the outer peripheral surface of the rod holding tube is extended. Since it is possible to move further down along the portion, it is avoided or suppressed that water adheres to the vicinity of the lower end opening of the insertion hole, which is located above the lower end of the extending portion. It is possible to prevent an ignition mistake while maintaining a good insulating state. As a result, the reliability of the spark ignition device is increased.

It is the schematic which shows the structure of an underwater combustion type vaporizer. It is sectional drawing which shows the structure of an underwater combustion burner. It is sectional drawing which shows the structure of a pilot burner. It is sectional drawing which expands and shows the insulator part of a rod holding tube. FIG. 5A is a view corresponding to FIG. 4 showing another configuration example of the insulator portion, FIG. 5B is a bottom view showing another configuration example of the insulator portion, and FIG. 5C is a bottom view showing still another configuration example of the insulator portion. FIG. 5A is a perspective view illustrating another configuration example of the lower end portion of the rod holding tube, and FIG. 5B is a perspective view illustrating another configuration example of the lower end portion of the rod holding tube.

  Hereinafter, an embodiment of a spark ignition device of a burner will be described based on the drawings. In addition, the following description of preferable embodiment is an illustration. FIG. 1 shows an outline of an underwater combustion type vaporizer 1 equipped with an underwater combustion burner to which the spark ignition device of the burner disclosed herein is applied. The underwater combustion type vaporizer 1 is a liquefied natural gas (LNG) vaporizer that is immersed in a water tank 11 and is formed by bending a large number of heat transfer tubes serving as LNG flow paths in multiple stages. The heat exchanger 12 and the downcomer 13 disposed in the water tank 11 are provided with the fuel gas supplied from a fuel gas supply source (not shown) and the air supplied through the blower 14. An underwater combustion burner 2 that burns at a position below the surface of the water, and a plurality of small burners that are disposed at the bottom of the water tank 11 and communicate with the lower end of the downcomer 13 and the combustion gas of the underwater combustion burner 2 is ejected. The sparge pipe 15 in which holes are formed and a stack 16 that is disposed in the upper part of the water tank 11 and exhausts combustion exhaust gas are configured. The underwater combustion type vaporizer 1 passes through the heat exchanger 12 while stirring the water in the water tank 11 by ejecting the combustion gas of the underwater combustion burner 2 as bubbles into the water tank 11 through the small holes of the sparge pipe 15. LNG to be heated. Thus, LNG is vaporized into natural gas (NG), which is sent out from the outlet of the heat exchanger 12. The underwater combustion type vaporizer 1 is capable of stirring the water in the water tank 11 by jetting the combustion gas into the water tank 11 as bubbles and reducing the temperature of the combustion exhaust gas discharged from the stack 16. Therefore, it is characterized by extremely high thermal efficiency.

  FIG. 2 shows the overall configuration of the underwater combustion burner 2. The underwater combustion burner 2 has its upper end closed and its lower end opened, and a supply port 23 for supplying air from the blower 14 to the underwater combustion burner 2 on the outer surface of the underwater combustion burner 2. Is provided so as to open outward.

  A main burner 26 is disposed in the combustion chamber 25 configured inside the underwater combustion burner 2. The main burner 26 includes a plurality of fuel gas nozzles 261, and the gas nozzles 261 are mutually equal in the circumferential direction so as to surround the lower end portion of the fuel gas supply pipe 262 disposed at the center position of the underwater combustion burner 2. They are arranged at intervals. The lower end of each gas nozzle 261 is arranged so that a nozzle (not shown) is opened downward, whereas the upper end portion is bent inward in the radial direction, and the bent end is a fuel end. A gas supply pipe 262 is connected. The fuel gas supply pipe 262 passes through the upper end of the closed underwater combustion burner 2 and extends to the outside. The end of the fuel gas supply pipe 262 is connected to a fuel gas supply source (not shown). ing.

  The underwater combustion burner 2 includes a pilot burner 3 in addition to the main burner 26 described above. The pilot burner 3 penetrates the upper end portion of the underwater combustion burner 2 and is inserted into the combustion chamber 25 at a position deviated from the center of the underwater combustion burner 2 and slightly inclined with respect to the vertical direction. The underwater combustion burner 2 is attached. The burner tip 33 provided at the lower end of the pilot burner 3 is not clearly shown in FIG. 2, but between the two adjacent specific fuel gas nozzles 261 among the plurality of fuel gas nozzles 261 in the main burner 26. Has been placed.

  FIG. 3 is a cross-sectional view showing the configuration of the pilot burner 3, and FIG. 4 is an enlarged cross-sectional view showing the insulator 43 that supports the spark rod 41 of the pilot burner 3. The pilot burner 3 includes a burner body 31 and a spark ignition device 4. Of these, the burner main body 31 has a pipe 32 that is bent at the upper end portion thereof and extends substantially in the vertical direction. A supply port 321 is connected to a gas supply source and into which fuel gas flows. On the other hand, a burner chip 33 is attached to the lower end of the pipe 32. The burner tip 33 includes an insertion portion 331 that is externally attached to the lower end of the pipe 32, a cylindrical hood portion 332, and a tip portion 333 that is a partition wall that separates the insertion portion 331 and the hood portion 332 from each other. ing.

  The spark ignition device 4 includes a spark rod 41 and a rod holding tube 42. The rod holding tube 42 is disposed so as to extend in a substantially vertical direction so as to be parallel to the pipe 32 of the burner body 31, and an upper end portion thereof is accommodated in the casing 45. The casing 45 is attached and fixed to the upper part of the underwater combustion burner 2, and a part of the burner body 31 is also accommodated in the casing 45. The rod holding tube 42 and the spark rod 41 are drawn so as to extend in the vertical direction in FIG. 3, but when attached to the underwater combustion burner 2, as shown in FIG. Slightly tilted.

  An intermediate portion of the spark rod 41 is inserted into the rod holding tube 42, and an upper end portion and a lower end portion of the spark rod 41 protrude from the upper end and the lower end of the rod holding tube 42, respectively. The spark rod 41 is supported by a bushing 421 on the upper end opening of the rod holding tube 42, and is supported by an insulator 43 on the lower end opening of the rod holding tube 42. Thus, the spark rod 41 is supported in an insulated state with respect to the rod holding tube 42.

  As described above, the upper end portion of the spark rod 41 is disposed in the casing 45, and a connector 411 to which a cable (not shown) is connected is attached to the upper end portion. On the other hand, the lower end portion of the spark rod 41 disposed so as to protrude from the lower end opening of the rod holding tube 42 is bent in an approximately L shape, and the bent tip penetrates the hood portion 332 of the burner tip 33 in the burner body 31. It is disposed in the formed through hole 335 having a predetermined shape. With this configuration, when a high voltage is applied to the spark rod 41 through the connector 411, spark discharge occurs between the bent tip of the spark rod 41 and the edge of the through hole 335 of the hood portion 332, and the pilot burner 3 It comes to ignite.

The insulator 43 that supports the spark rod 41 at the lower end of the rod holding tube 42 is made of, for example, polytetrafluoroethylene (trade name: Teflon (registered trademark)), and as shown in an enlarged view in FIG. Has an insertion hole 431 into which is inserted. The insulator 43 is fitted into a substantially cylindrical insulator support 44, and a step portion 441 for holding the insulator 43 is provided at a lower end portion of the insulator support 44. By attaching and fixing the insulator support 44 to the lower end of the rod holding tube 42, the insulator 43 is disposed at the lower end portion of the rod holding tube 42. In the following description, since the rod holding tube 42 and the insulator support 44 are integrated, for convenience, the term “the lower end of the rod holding tube 42” or “the lower end opening of the rod holding tube 42” is used. The portion may correspond to the insulator support 44 in practice.

  The lower end surface 432 of the insulator 43 is exposed downward through the lower end opening of the rod holding tube 42, and the lower end surface 432 of the insulator 43 extends from the lower end opening of the insertion hole 431 toward the peripheral edge thereof, in other words, from the center. It is formed so as to incline downward toward the outer peripheral side of the lower end surface. That is, the lower end surface 432 of the insulator 43 is formed in a mortar shape that is recessed upward. For this reason, the lower end position of the rod holding tube 42 is configured to be downward in the height direction with respect to the lower end opening of the insertion hole 431 that opens to the lower end surface of the insulator 43. This is because the rod holding tube 42 is provided with an extending portion 423 that is continuous with the outer peripheral surface of the rod holding tube 42 and extends downward to a position below the height position of the lower end opening of the insertion hole 431. It can be paraphrased.

  As shown in FIG. 3, the casing 45 described above is formed with an inlet 451 for instrumentation air for drying the spark rod 41, and the rod holding tube 42 disposed in the casing 45. An inflow hole 426 through which instrument air flows into the rod holding tube 42 is formed through the upper end portion. Here, the insertion hole 431 of the insulator 43 is formed to have a larger diameter than the outer diameter of the spark rod 41 so that a slight gap is provided between the insertion hole 431 and the spark rod 41, as shown in FIG. As a result, the instrument air introduced into the casing 45 flows into the rod holding tube 42 through the inflow hole 426 and flows downward in the rod holding tube 42 as indicated by arrows in FIG. It flows out of the rod holding tube 42 through the insertion hole 431 of the insulator 43. The instrument air is configured to always flow in the rod holding tube 42, and thereby the periphery of the spark rod 41 is always dried, so that the insulation state of the spark rod 41 is excellent even in a high humidity environment. I try to keep it.

  Here, the burner activation of the underwater combustion type vaporizer 1 will be briefly described. When the underwater combustion type vaporizer 1 is activated, only the blower 14 is first operated, and the downcomer 13 and the sparge pipe 15 are passed through the underwater combustion burner 2. Air only into the air. As a result, the water stored in the downcomer 13 and the sparge pipe 15 is discharged (that is, a purge operation). Then, after supplying a predetermined amount of air set in advance according to the volumes of the downcomer 13 and the sparger pipe 15, the fuel gas is supplied to the pilot burner 3 of the underwater combustion burner 2 and a high voltage is applied to the spark rod 41. Apply. As a result, as described above, a spark discharge is generated between the bent tip of the spark rod 41 and the edge of the through hole 335 of the hood portion 332, and the pilot burner 3 is ignited. Thereafter, the main burner 26 is ignited by the pilot burner 3, and the burner activation of the underwater combustion type vaporizer 1 is completed.

  When the underwater combustion type vaporizer 1 is stopped, the inside of the underwater combustion burner 2 is in a high humidity environment, so that condensation is likely to adhere to the spark ignition device 4 of the pilot burner 3. However, by constantly flowing the instrumentation air for drying into the rod holding tube 42, the periphery of the spark rod 41 held by the rod holding tube 42 is dried, and the insulating state of the spark rod 41 is kept good. It is. For this reason, when the underwater combustion type vaporizer 1 is started, an ignition error of the spark ignition device can be prevented and the pilot burner 3 can be reliably ignited. This shortens the startup time of the underwater combustion burner 2 and thus the startup time of the underwater combustion type vaporizer 1.

  On the other hand, for example, when the outside air temperature is extremely low, a large amount of dew condensation adheres to the outer peripheral surface of the rod holding tube 42. As shown in FIG. 2, the rod holding tube 42 is disposed so as to extend in a substantially vertical direction. Therefore, the dew that adheres to the outer peripheral surface of the rod holding tube 42 flows down due to gravity, and the rod holding tube 42. A large amount of water accumulates at the lower end of the.

  Here, in the rod holding tube 42 having the conventional structure, the lower end surface of the insulator 43 and the lower end surface of the rod holding tube 42 are at the same height, and the lower end surface of the insulator 43 is a flat surface. When a large amount of water accumulates at the lower end, the water also adheres to the vicinity of the lower end opening of the insertion hole 431 of the insulator 43. As a result, even if instrumentation air is constantly flowed and instrumentation air is caused to flow out from the lower end opening of the insertion hole 431, insulation failure of the spark rod 41 may be caused.

  On the other hand, as shown in FIG. 4, the rod holding tube 42 described above has an extending portion 423 that extends to a lower position in the height direction than the lower end opening of the insertion hole 431. For this reason, even if a large amount of condensation adheres to the outer peripheral surface of the rod holding tube 42 and water accumulates at the lower end portion of the rod holding tube 42, that is, the lower end portion of the extending portion 423, the vicinity of the lower end opening of the insertion hole 431 Water is prevented from adhering to the surface.

  Further, since the lower end surface of the insulator 43 is formed in a mortar shape, when dew condensation adheres to the lower end surface, the dew condensation flows down from the center side toward the outer peripheral side due to gravity. This also prevents water from adhering to the vicinity of the lower end opening of the insertion hole 431.

  Thus, by providing the extension portion 423 described above and the lower end surface of the insulator 43 having a mortar shape, water hardly adheres to the vicinity of the lower end opening of the insertion hole 431 even if the condensation is large. In addition, even if water is attached, the amount is very small, and the attached minute amount of water is blown away by the instrument air flowing out from the lower end opening of the insertion hole 431.

  Thus, in this configuration, it becomes possible to maintain the insulating state of the spark rod 41 well even in an environment where dew condensation is large, and by igniting the pilot burner 3 reliably by avoiding or preventing ignition mistakes, It becomes possible to shorten the starting time of the underwater combustion type vaporizer 1.

  In addition, the shape of the lower end surface of the insulator 43 is not limited to the shape shown in FIG. FIG. 5 shows a modification regarding the shape of the lower end surface of the insulator 43. For example, in FIG. 5A, only the central portion of the lower end surface 432 of the insulator 43 is an inclined surface inclined downward, and the outer peripheral edge portion is a flat surface. Even in this configuration, since the spark ignition device 4 has the extending portion 423 of the rod holding tube 42 and the inclined lower end surface 432 of the insulator 43, the effect of preventing insulation failure is the shape shown in FIG. Is equivalent to

  Although not shown in the figure, the height position of the lower end opening of the insertion hole 431 is relatively set by providing a hole recessed from the lower end surface of the insulator 43 without tilting the lower end surface 432 of the insulator 43 downward. Therefore, the extended portion 423 of the rod holding tube 42 may be formed.

  5 (b) and 5 (c) are bottom views showing the lower end surface of the insulator 43. As shown in FIG. 5 (b), in order to promote drainage of dew condensation adhering to the lower end surface, the insulator 43 A plurality of drainage grooves 433 extending from the lower end opening of the insertion hole 431 to the outer peripheral edge (eight in the illustrated example) may be formed on the inclined lower end surface 432. Further, as shown in FIG. 5 (c), from the lower end opening of the insertion hole 431 to the outer peripheral edge by forming the shape alternately bent in the circumferential direction so that the inclined lower end surface 432 of the insulator 43 has a waveform. You may make it provide many extended drainage grooves. In addition, you may combine Fig.5 (a) and FIG.5 (b) or (c).

  6 (a) and 6 (b) are different from the insulator 43 of FIGS. 4 and 5 in that the lower end surface 461 of the insulator 46 is flattened while the lower end of the insulator support 44 is extended downward. A configuration example is shown in which extended portions 424 and 425 that are positioned below the lower end opening of the hole 431 are provided. That is, in FIG. 6A, a step portion 441 for holding the insulator 46 is provided at the intermediate portion of the insulator support 44 so as to abut against the flat lower end surface 461 of the insulator 46, and below the step portion 441. A cylindrical extending portion 424 having the same diameter as the insulator support 44 is provided. Also in this configuration, since the lower end of the extending portion 424 is located below the lower end opening of the insertion hole 431 that opens to the lower end surface of the insulator 46, it is transmitted along the outer peripheral surface of the rod holding tube 42. Then, the water that has moved downward is guided to the lower end of the extending portion 424, and water is prevented from adhering to the vicinity of the lower end opening of the insertion hole 431.

  Such an extended portion is not limited to a cylindrical shape surrounding the entire outer periphery of the insertion hole 431. For example, as shown in FIG. 6B, a rod-like or piece-like extending portion 425 extending downward may be attached to the lower end portion of the rod holding tube 42 (insulator support 44) at a predetermined position in the circumferential direction. Even in this case, it is possible to prevent water from adhering to the vicinity of the lower end opening of the insertion hole 431 by guiding the water moved downward along the outer peripheral surface of the rod holding tube 42 to the lower end of the extending portion 425. It is. Such a bar-like or piece-like extending portion 425 can be retrofitted to an existing underwater combustion burner. In the illustrated example, a rod-like extending portion 425 is attached to the outer peripheral surface of the rod holding tube 42. Such a retrofitting structure makes it possible to take measures to avoid ignition mistakes with respect to existing underwater combustion burners simply and at low cost. Note that the number of the extending portions 425 is not particularly limited, and can be an appropriate number. However, the larger the number, the more the water adheres near the lower end opening of the insertion hole 431. The effect to prevent becomes high.

  Moreover, although the diameter of the extending part 424 is not the same as that of the insulator support 44, illustration is omitted, but the diameter may be smaller or larger than that of the insulator support 44. Furthermore, you may form so that the diameter of the extension part 424 may be expanded as it goes below.

  However, from the viewpoint of workability, it is easier to machine the lower end surface of the insulator 43 as shown in FIGS.

  In addition, here, the configuration of the characteristic spark ignition device disclosed herein has been described by taking the spark ignition device in the pilot burner 3 of the underwater combustion burner 2 in the underwater combustion type vaporizer 1 as an example. Is not limited to being applied to the underwater combustion burner 2 of the underwater combustion type vaporizer 1, but can also be applied to other underwater combustion burners and other general gas burners. It can also be applied as a spark ignition device for an oil burner. This spark igniter is particularly useful as a spark igniter for a burner used in an environment in which a large amount of dew condensation adheres to an insulation failure.

As described above, the spark ignition device of the burner in the underwater combustion type vaporizer disclosed herein can maintain a good insulation state and prevent ignition mistakes even when a large amount of condensation occurs. For example, it is useful as a spark ignition device for a pilot burner in an underwater combustion burner.

3 Pilot burner (burner)
31 Burner body 321 Supply port 33 Burner tip 4 Spark ignition device 41 Spark rod 42 Rod holding tube 423 Extension portion 424 Extension portion 425 Extension portion 43 Insulator 431 Insertion hole 432 Lower end surface 46 of the insulator Insulator 461 Lower end surface of the insulator

Claims (2)

A fuel gas supply port is provided at the base end, and a burner body provided with a burner tip at the tip thereof;
A spark rod which is disposed so as to extend in the vertical direction and whose tip is disposed in proximity to the burner tip;
A rod holding tube for accommodating at least an intermediate portion excluding the tip of the spark rod;
An insulator inserted into a lower end portion of the rod holding tube and supporting an intermediate portion of the spark rod in an insulated state;
The insulator is formed with an insertion hole through which the spark rod is inserted, and the insertion hole opens on a lower end surface of the insulator exposed downward through a lower end opening of the rod holding tube,
The rod holding tube is disposed so as to surround the outer periphery of the lower end opening of the insertion hole, is continuous with the outer peripheral surface of the rod holding tube, and is lower than the height position of the lower end opening of the insertion hole. A spark ignition device for a burner in an underwater combustion type vaporizer provided with an extending portion extending downward to a position. The spark ignition device for a burner according to claim 1,
A spark ignition device for a burner in an underwater combustion type vaporizer , wherein a lower end surface of the insulator is formed to be inclined downward from the lower end opening of the insertion hole toward the outer peripheral side.

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