JP4897005B2 - Burner equipment - Google Patents

Description

  The present invention relates to a burner device.

  The burner device requires a flow path for supplying fuel and combustion air and ignition means. As the ignition means, those that generate electric sparks are widely used. As such ignition means, there is one that causes a spark discharge between a pipe serving as a fuel flow path and a tip portion of an electrode rod disposed along the pipe.

  Such a burner device can also be used as a burner of a radiant tube heating device as described in Patent Document 1, for example.

  For example, Patent Documents 2 and 3 include a conductive fuel supply pipe extending long inside the apparatus and an electrode rod arranged in parallel to the fuel supply pipe, and a voltage is applied between the fuel supply pipe and the electrode rod. There is described a radiant tube burner having ignition means for generating a spark discharge by applying.

  In such a radiant tube burner, the outer wall of the device is generally separated from the ignition position, the insulator is broken due to the difference in thermal expansion coefficient between the insulator protecting the electrode rod and the electrode rod, the fuel supply pipe and the electrode rod The discharge position is shifted due to the difference in thermal expansion coefficient.

  Further, in the radiant tube type heating device, there is also a device that uses, as a pilot burner, the above-described burner device that is ignited by the electric spark for ignition of the main combustion burner. In the case of such a pilot burner, if the discharge position is shifted due to a difference in thermal expansion coefficient, an electric spark is generated in a space without fuel, and thus there is a problem that ignition cannot be performed at all.

  FIG. 2 shows a radiant tube burner 22 using a pilot burner 21 having conventional ignition means. In the conventional pilot burner 21 for the radiant tube burner 22, the electrode rod 25 wired in parallel with the pipe 23 is connected to the small hole 24 provided in the conductive pipe 23 for supplying the mixed gas of the pilot fuel gas and the pilot air. The pilot burner 21 is ignited by discharging. The electrode rod 25 is insulated by an insulator 26.

  In the radiant tube burner 21, in order to prevent the displacement of the ignition position due to the difference in thermal expansion coefficient as described above, an insulator 26 near the tip of the electrode rod 25 is piped by a fixing member 27 as shown in FIG. The other end of the electrode rod 25 and the insulator 26 may be slidably passed through the blind flange 28 that seals the outer wall. However, since the airtightness of the apparatus is required, a seal structure 29 such as a gland packing is required between the insulator 26 and the blind flange 28. For this reason, the sliding frictional force of the lever 26 against the blind flange 28 is increased, and a large load is applied to the fixing member 27 at the tip of the lever 26. For this reason, in the burner device having such a structure, the insulator 26 and the fixing member 27 are often damaged.

  Furthermore, in recent years, as described in Patent Documents 4 and 5, the temperature of combustion air supplied to the radiant tube burner tends to increase as a result of improving the thermal efficiency using a heat exchanger or a heat accumulator. For this reason, problems due to thermal expansion of the ignition means are likely to occur.

Japanese Patent Publication No. 1-37645 Japanese Patent Laid-Open No. 9-14612 Japanese Patent Laid-Open No. 11-201416 JP 2001-330209 A JP 2007-278893 A

  In view of the above problems, an object of the present invention is to provide a burner device in which the discharge position does not shift due to thermal expansion.

In order to solve the above problems, a burner device according to the present invention includes a conductive fuel supply pipe that feeds fuel through the fixed wall, which is an outer wall of the device, and the fuel supply pipe that penetrates the fixed wall. The electrode rod is disposed along the fuel supply pipe while being electrically insulated, and has a tip that is close to the fuel supply pipe. The electrode rod is fixed to the fuel supply pipe in the vicinity of the tip. A portion that penetrates the wall is fixed to the fixed wall, is divided between the portion fixed to the fuel supply pipe and the portion fixed to the fixed wall, and is connected by fitting a conductive sleeve. At least one of the part fixed to the fuel supply pipe and the part fixed to the fixed wall is slidable within the sleeve .

  According to this configuration, the difference in thermal expansion between the fuel supply pipe and the electrode rod is absorbed by changing the gap between the electrode rods divided while ensuring the conduction of the electrode rod divided by the conductive sleeve. it can. Thereby, since the discharge position does not shift, there is no ignition failure and ignition is reliable. Further, by absorbing the dimensional change due to thermal expansion, a large stress is not applied to the fixing structure of the electrode rod tip, and there is no problem that the insulator and the fixing member are damaged.

  Moreover, the burner apparatus of this invention WHEREIN: One side of the said sleeve may be fixed to the said electrode rod.

  According to this configuration, the sleeve can be prevented from falling off by an inexpensive method such as welding.

  In the burner device of the present invention, the electrode rod may be held on the fuel supply pipe via an insulator.

  According to this configuration, it is possible to prevent an undesired short circuit or discharge due to thermal deformation of the electrode rod.

  The burner device of the present invention is particularly suitable for a pilot burner for a radiant tube burner in which the electrode rod and the fuel supply pipe are long and the temperature of the combustion air is high.

  According to the present invention, since the electrode rod disposed along the fuel supply pipe is divided in the middle and is connected to be stretchable by the conductive sleeve, there is a difference in thermal expansion coefficient between the fuel supply pipe and the electrode rod. Even in such a case, the ignition can be ensured by absorbing the difference in dimensional change and maintaining the discharge position, and a large load is not applied to the electrode rod fixing structure to cause damage.

It is sectional drawing of the radiant tube burner provided with the pilot burner of 1st Embodiment of this invention. It is sectional drawing of the radiant tube burner provided with the conventional pilot burner. It is sectional drawing of a different radiant tube burner provided with the conventional pilot burner.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a combustion exhaust gas circulation type radiant tube burner 2 provided with a pilot burner (burner device) 1 according to one embodiment of the present invention. The radiant tube burner 2 seals the end of the radiant tube 3 and the fuel pipe 5 for supplying fuel to the blind flange (fixed wall) 4 that seals the opening of the outer wall of the apparatus, and the pilot gas and the pilot air A conductive pilot mixed gas pipe (fuel supply pipe) 6 made of, for example, stainless steel is fixed by welding. The ends of the fuel pipe 5 and the mixed gas pipe 6 are open toward the inside of the flame holding cylinder 7 held in the radiant tube 3.

  The pilot burner 1 is provided with an electrode rod 8 made of, for example, a Kanthal alloy wire along a mixed gas pipe 6. The electrode rod 8 is bent so that the tip is close to the mixed gas pipe 6 and faces the ignition hole 9 formed in the mixed gas pipe 6. The electrode rod 8 has an insulator 10 fixed in the vicinity of the tip, and the insulator 10 is held by a fixing member 11 attached to the mixed gas pipe 6, so that the tip portion is fixed facing the ignition hole 9. . The insulator 10 may be formed with a recess into which a screw that is screwed into the fixing member 11 is fitted, for example, to enable reliable fixing. In addition, the electrode rod 8 may be fixed to the insulator 10 with plug cement (inorganic adhesive) or the like so that the bent tip portion does not deviate from the position facing the ignition hole 9.

  Further, the electrode rod 8 has a lever 12 fixed to a portion passing through the blind flange 4, and the lever 12 is fixed to the blind flange 4 in an airtight manner. The central portion of the electrode rod 8 is slid by the fixing member 14 so as to secure an insulation distance from the mixed gas pipe 6 through a cylindrical insulator 13 slidably fitted to the electrode rod 8. It is held movable. On both sides of the insulator 13 of the electrode rod 8, a caulking member 15 is fixed by pressure with a clearance from the insulator 13. This caulking member 15 prevents the position of the lever 13 from deviating greatly. These insulators 10, 12, and 13 ensure insulation between the blind flange 4 and the mixed gas pipe 6 and the electrode rod 8, so that an unexpected discharge or short circuit does not occur in a place other than the tip of the electrode rod 8. Yes. In some cases, the insulator 13 may be fixed to the fixing member 14 in the same manner as the insulator 10. Further, without using the caulking member 15, the displacement of the insulator 13 may be prevented by caulking the electrode rod 8 itself to create a bulging portion.

  Furthermore, the electrode rod 8 is divided in the vicinity of the blind flange 4 and is connected to each other by fitting a conductive sleeve 16 made of, for example, stainless steel. The sleeve 16 is fixed to the electrode rod 8 on the blind flange 4 side (upstream side) by welding 17, but is not fixed to the electrode rod 8 on the opposite side (downstream side). The rod 8 can be easily inserted into and removed from the sleeve 16.

  The mixed gas pipe 6 made of stainless steel has a thermal expansion coefficient about 1.3 times that of the electrode rod 8 made of Kanthal alloy. For this reason, when the temperature in the radiant tube burner 2 rises, the tip of the electrode rod 8 is moved to the downstream side largely compared to the extension of the electrode rod 8 as a whole. However, since the electrode rod 8 is divided into two parts in the vicinity of the portion held by the blind flange 4, the gap of this portion widens in the sleeve 16, thereby applying tension to the electrode rod 8. I won't let you.

  Further, the sleeve 16 is in contact with the divided electrode bars 8 regardless of the size of the gap between the electrode bars 8, and maintains the electrical connection between them. Further, the insulator 13 fixed to the central portion of the mixed gas pipe 6 also allows the electrode rod 8 to slide and does not give tension.

  For this reason, the gap between the electrode rods 8 is determined so that the electrode rods 8 do not contact each other even when the temperature of the mixed gas pipe 6 is low. Further, the sleeve 16 has a sufficiently long overall length and an insertion length of the electrode rod so that the electrode rod 8 does not fall out even if the mixed gas pipe 6 becomes hot and the gap between the electrode rods 8 becomes large.

  As a result, regardless of the temperature of the mixed gas pipe 6 and itself, the electrode rod 8 always has its tip portion opposed to the ignition hole 9, and between the mixed gas pipe 6 and the electrode rod 8 outside the blind flange 4. When a predetermined voltage is applied, spark discharge is generated between the tip of the electrode rod 8 and the mixed gas pipe 6 in the ignition hole 9. Since the pilot burner 1 always generates a spark discharge in the ignition hole 9, the fuel can be reliably ignited.

  Further, since tension does not act on the electrode rod 8, excessive stress is not applied to the insulator 10 and the fixing member 11, and there is no fear of breakage.

  In this embodiment, the sleeve 16 is welded to the electrode rod 8 at the end on the blind flange 4 side so that the sleeve 16 does not fall out of the electrode rod 8. May be fixed by a method such as crimping. Further, a partition wall may be provided at the center of the hole of the sleeve 16 to secure an insertion length that is slidable with respect to the electrode rods 8 on both sides and that does not fall off even if it is biased to one side.

  The sleeve 16 is preferably provided at a position close to the blind flange 4 where the temperature does not easily rise, but may be provided at any position of the electrode bar 8. Further, the sleeve 16 may be fixed to the mixed gas pipe 6 through an insulator.

  The pilot burner for the radiant tube burner as in this embodiment generally has a high combustion temperature and is installed through the thick heat insulating layer of the furnace body, so that a spark discharge is generated from the blind flange which is the outer wall of the apparatus. The distance to the position where the fuel is ignited is long. For this reason, since the difference in dimensional change due to thermal expansion between the fuel supply pipe (mixed gas pipe) and the electrode rod increases, the reliability of ignition is improved by applying the present invention, and the insulator and electrode rod fixing structure The effect which can prevent the damage of is large.

  The radiant tube burner to which the present invention can be applied is applicable not only to the circulation type as in the above embodiment, but also to a non-circulation type, for example, a single-end type radiant tube burner. Furthermore, the present invention can be applied to other types of burner devices, and is not limited to a pilot burner, but can be applied to any burner as long as it is directly ignited by spark discharge from an electrode rod. it can.

  In addition, the burner device to which the present invention is applied can increase the operating temperature because there is no displacement of the ignition position due to thermal expansion and no damage to the fixed structure.

1 ... Pilot burner 2 ... Radiant tube burner 3 ... Radiant tube 4 ... Blind flange (fixed wall)
6 ... Mixed gas pipe (fuel supply pipe)
DESCRIPTION OF SYMBOLS 8 ... Electrode rod 9 ... Ignition hole 10 ... insulator 11 ... fixing member 12 ... insulator 13 ... insulator 15 ... caulking member 16 ... sleeve

Claims (4)

An energized fuel supply pipe that passes through a fixed wall that is an outer wall of the device and supplies fuel;
An electrode rod penetrating the fixed wall and disposed along the fuel supply pipe while being electrically insulated from the fuel supply pipe, and a tip of the electrode bar close to the fuel supply pipe;
The electrode rod is fixed to the fuel supply pipe in the vicinity of the tip, a portion that penetrates the fixed wall is fixed to the fixed wall, and a portion fixed to the fuel supply pipe and a portion fixed to the fixed wall Divided between and connected by fitting a conductive sleeve ,
At least one of a portion fixed to the fuel supply pipe and a portion fixed to the fixed wall is slidable within the sleeve .   The burner device according to claim 1, wherein one side of the sleeve is fixed to the electrode bar.   The burner device according to claim 1 or 2, wherein the electrode rod is held on the fuel supply pipe via an insulator.   The burner device according to any one of claims 1 to 3, wherein the burner device is a pilot burner for a radiant tube burner.

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