JP2023032512A - surface combustion burner - Google Patents

Abstract

To provide a surface combustion burner which can improve the durability of a discharge rod end part of a spark rod.SOLUTION: A surface combustion burner 1 comprises an air pipe 3, a fuel pipe 4, a combustion header 2, a ventilation member 26, and a spark rod 5. A plurality of fuel injection outlets 221, 222 for injecting a fuel gas F, and a plurality of first air injection ports 23 for injecting combustion air A are formed at a nozzle part 21 of the combustion header 2. A discharge protrusion 210 is formed at a position opposing a discharge rod end part 511 of the spark rod 5 in a radial direction R at an outside face of a region of the nozzle part 21 at a base end side L2 in an axial direction L. The plurality of fuel injection ports 221, 222 are formed at a tip side L1 in the axial direction L rather than a forming position of the discharge protrusion 210.SELECTED DRAWING: Figure 1

Description

The present invention relates to surface combustion burners.

There are various types of burners that form flames by combustion of fuel gas and combustion air. Among them, for example, Patent Document 1 discloses a surface combustion burner that mixes and burns fuel gas and combustion air on the surface of a gas-permeable member. In this surface combustion burner, the fuel gas jetted from the combustion header and flowing from the inside to the outside of the gas-permeable member and the combustion air flowing outside the combustion header are mixed and burned on the surface of the gas-permeable member, Create a flame in the air tube. In addition, the concentration of the fuel gas ejected from the combustion header is less likely to be biased.

JP 2017-146028 A

In a surface-burning burner, a spark rod for igniting a mixture of fuel gas and combustion air is positioned outside and opposite the combustion header. However, in the conventional surface combustion burner, no special consideration is given to the arrangement position of the discharge rod end of the spark rod, which generates sparks between the discharge header and the ground portion provided in the combustion header. Therefore, there is a problem that the discharge rod end portion of the spark rod is heated to a high temperature by the flame when the air-fuel mixture is burned. Therefore, further measures are required to improve the durability of the discharge rod end.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object thereof is to provide a surface combustion burner capable of improving the durability of the discharge rod end portion of the spark rod.

One aspect of the present invention is
an air pipe through which combustion air passes;
a fuel pipe disposed within the air pipe through which fuel gas passes;
a combustion header connected to the axial tip side of the fuel pipe and arranged in the air pipe, and having a nozzle portion and a flange portion provided on the axial base end side of the nozzle portion;
an air-permeable member provided on the outer surface of the nozzle portion and formed of a knitted fabric or a porous material;
a spark rod disposed through the flange portion and having a discharge rod end disposed at a position facing the outer surface of the nozzle portion;
The nozzle portion is formed with a plurality of fuel ejection ports for ejecting the fuel gas and a plurality of first air ejection ports for ejecting the combustion air, and the flange portion is formed with: A plurality of second air ejection ports are formed for ejecting the combustion air,
A discharge projection is formed at a position facing the discharge rod end on the outer surface of the nozzle portion on the base end side in the axial direction,
The plurality of fuel ejection ports are in the surface combustion burner formed on the tip end side in the axial direction with respect to the formation position of the discharge convex portion.

In the surface combustion burner of the one aspect, the formation positions of the discharge rod end portion of the spark rod and the discharge convex portion of the nozzle portion are devised. Specifically, a discharge projection is formed at a position facing the discharge rod end on the outer surface of the nozzle portion on the base end side in the axial direction. Further, the discharge rod end portion is arranged at a position facing the outer surface of the portion on the base end side in the axial direction of the nozzle portion. Furthermore, the plurality of fuel ejection ports are formed on the tip end side in the axial direction from the formation position of the discharge convex portion.

With these configurations, the fuel gas ejected from the plurality of fuel ejection openings of the nozzle section, and the combustion air ejected from the plurality of first air ejection openings of the nozzle section and the plurality of second air ejection openings of the flange section. When combustion of the air-fuel mixture is performed, it is possible to make it difficult for the flame due to combustion in the vicinity of the surface of the gas-permeable member to come into contact with the discharge rod end.

Therefore, according to the surface combustion burner of the aspect, the durability of the discharge rod end portion of the spark rod can be improved.

FIG. 4 is a cross-sectional view taken along line II in FIG. 3, showing the surface combustion burner according to the embodiment; FIG. 4 is a cross-sectional view taken along the line II-II in FIG. 3, showing the surface combustion burner according to the embodiment; The figure which shows the surface combustion burner concerning embodiment, and is the III arrow directional view in FIG. FIG. 2 is a diagram showing a surface combustion burner according to an embodiment, and is a cross-sectional view showing an enlarged part of FIG. 1 ;

A preferred embodiment of the surface combustion burner described above will be described with reference to the drawings.
<Embodiment>
The surface combustion burner 1 of this embodiment comprises an air pipe 3, a fuel pipe 4, a combustion header 2, a ventilation member 26 and a spark rod 5, as shown in FIGS. The air pipe 3 is configured so that the combustion air A passes through it. The fuel pipe 4 is arranged inside the air pipe 3 and configured to allow the fuel gas F to pass therethrough. The combustion header 2 is connected to the distal end side L1 of the fuel pipe 4 in the axial direction L and arranged in the air pipe 3, and is connected to the nozzle portion 21 and the proximal end side L2 of the nozzle portion 21 in the axial direction L. and a flange portion 24 provided. 3, the air-permeable member 26 is omitted.

The nozzle portion 21 is formed with a plurality of fuel ejection openings 221 and 222 for ejecting the fuel gas F and a plurality of first air ejection openings 23 for ejecting the combustion air A. As shown in FIG. A plurality of second air ejection ports 241 for ejecting the combustion air A are formed in the flange portion 24 .

The air-permeable member 26 is provided on the outer surface of the nozzle portion 21 and is formed of a metal knitted fabric. The spark rod 5 is arranged to penetrate the flange portion 24 in the axial direction L, and has a discharge rod end portion 511 at a position facing the outer surface of the nozzle portion 21 . A discharge convex portion 210 is formed at a position facing the discharge rod end portion 511 in the radial direction R on the outer surface of the base end side L2 in the axial direction L of the nozzle portion 21 . The plurality of fuel ejection ports 221 and 222 are formed on the tip side L1 in the axial direction L from the formation position of the discharge convex portion 210 .

In this embodiment, the axial direction L refers to a direction parallel to the central axes of the air pipe 3 and the fuel pipe 4 . In the axial direction L, the downstream side of the flow of the combustion air A in the air pipe 3 and the downstream side of the flow of the fuel gas F in the fuel pipe 4 are referred to as the tip end side L1. This is referred to as the base end side L2. The circumferential direction C refers to the direction around the central axes of the air pipe 3 and the fuel pipe 4 . The radial direction R is a radial direction that is perpendicular to the axial direction L and centered on the central axes of the air pipe 3 and the fuel pipe 4 .

The surface combustion burner 1 of this embodiment will be described in detail below.
The surface combustion burner 1 of this embodiment is attached to a heating furnace or the like and used to heat the atmosphere gas in the furnace. As shown in FIGS. 1 and 2, the air pipe 3 and the fuel pipe 4 are arranged parallel to each other and have a double pipe structure. The tip of the air pipe 3 in the axial direction L is located further toward the tip side L1 in the axial direction L than the tip of the combustion header 2 in the axial direction L. As shown in FIG. The entire outer circumference of the combustion header 2 is covered with air pipes 3 . A slight gap is formed between the flange portion 24 of the combustion header 2 and the air pipe 3 when the combustion header 2 is arranged inside the air pipe 3 . In addition, in the structure of the surface combustion burner 1 actually used, the air pipe 3 may be arranged on the inner peripheral side of the exhaust pipe through which exhaust gas after combustion flows.

(Combustion header 2)
As shown in FIG. 1 , the nozzle portion 21 of the combustion header 2 has a parallel portion 212 parallel to the axial direction L and an inclined portion 211 located on the tip side L1 of the parallel portion 212 in the axial direction L. The inclined portion 211 has a dimension in the radial direction R that decreases toward the distal end side L1 in the axial direction L, and the air-permeable member 26 is arranged to face the outer surface of the inclined portion 211 . The outer surface of the inclined portion 211 of the nozzle portion 21 is formed as a tapered outer surface 201 whose outer shape (dimension in the radial direction R) decreases toward the tip end side L1 in the axial direction L.

As shown in FIGS. 2 and 3, the nozzle portion 21 has a convex portion 22 formed with a plurality of first fuel ejection ports 221 and a plurality of recess portions 230 forming the first air ejection ports 23. They are arranged alternately in the direction C. Each concave portion 230 is formed to be recessed inward in the radial direction R from the outer surface of the convex portion 22 . The first fuel ejection openings 221 and the first air ejection openings 23 are arranged alternately at a plurality of locations in the circumferential direction C of the combustion header 2 .

The flange portion 24 has a disk shape and is formed to protrude outward in the radial direction R from the nozzle portion 21 at the end portion on the base end side L2 in the axial direction L of the combustion header 2 . The flange portion 24 is formed with an insertion opening 242 for inserting the spark rod 5 in addition to the plurality of second air ejection openings 241 . Also, one of the second air jets 241 functions as a flame monitoring port 243 in which a flame detector for monitoring the state of flame formation is arranged.

As shown in FIGS. 1 and 2, a fuel passage 20 through which the fuel gas F is supplied from the fuel pipe 4 is formed in the central portion of the nozzle portion 21 and the flange portion 24 including the central axis. A portion of the fuel passage 20 on the tip end side L1 in the axial direction L is closed. The central axis of the combustion header 2 is parallel to the central axes of the air pipes 3 and the fuel pipes 4 . The fuel passage 20 is formed in the center including the central axis of the combustion header 2 .

As shown in FIGS. 1 and 3 , the plurality of first fuel ejection ports 221 are formed by branching outward in the radial direction R from the fuel passage 20 at the plurality of protrusions 22 . A plurality of first fuel injection ports 221 are formed at a plurality of locations around the center axis of the combustion header 2 so as to communicate the fuel passage 20 with the tapered outer surface 201 . A plurality of first fuel ejection ports 221 are formed along the radial direction R. As shown in FIG.

As shown in FIG. 2 , a portion of the plurality of first air ejection ports 23 on the base end side L2 in the axial direction L is formed as a through hole 231 . A portion on the tip side L1 is formed as a recess 230 communicating with a through hole 231 . The plurality of second air ejection ports 241 are arranged in the circumferential direction C of the flange portion 24 and are formed in a state of penetrating the flange portion 24 in the axial direction L. As shown in FIG.

As shown in FIG. 1 , the plurality of fuel ejection ports 221 and 222 of this embodiment are located on the base end side L2 in the axial direction L of the plurality of first fuel ejection ports 221 and the plurality of first fuel ejection ports 221. and a second fuel ejection port 222 that A plurality of first fuel ejection ports 221 are formed at a plurality of locations in the axial direction L and the circumferential direction C of the inclined portion 211 of the nozzle portion 21 . The second fuel ejection port 222 is located on the base end side L2 in the axial direction L of the formation position of the plurality of first fuel ejection ports 221 in the parallel portion 212 of the nozzle portion 21, and is the formation position of the discharge convex portion 210. It is formed at a position closer to the tip end side L1 in the axial direction L than the .

Further, as shown in FIG. 4 , the second fuel ejection port 222 is formed at a position overlapping the arrangement position of the discharge rod end portion 511 in the circumferential direction C of the parallel portion 212 of the nozzle portion 21 . In other words, the second fuel ejection port 222 is located at a position facing the discharge rod end portion 511 in the radial direction R, or at a position facing the discharge rod end portion 511 in the radial direction R, at the tip side L1 in the axial direction L. is formed at the position of The fuel gas F ejected from the second fuel ejection port 222 is ejected to the vicinity of the spark generation site by the discharge rod end portion 511 and the discharge convex portion 210 . As a result, the ignitability of the air-fuel mixture by the spark generated between the discharge rod end portion 511 and the discharge convex portion 210 can be enhanced.

As shown in FIG. 3, regarding the formation position of the second fuel ejection port 222, the position overlapping the arrangement position of the discharge rod end portion 511 in the circumferential direction C of the parallel portion 212 of the nozzle portion 21 is, for example, the discharge rod The position may be within 5° on both sides in the circumferential direction C with respect to the center position in the circumferential direction C of the end portion 511 . Only one second fuel ejection port 222 is formed in this embodiment. The second fuel ejection ports 222 may be formed dispersedly on both sides in the circumferential direction C centered on the position in the circumferential direction C of the discharge rod end portion 511 .

As shown in FIGS. 1 and 2, the combustion header 2 of this embodiment includes a fuel passage 20, a nozzle portion 21, a plurality of first fuel ejection ports 221, a portion of the second fuel ejection ports 222, and a plurality of first fuel ejection ports. A first header part 2A in which an air ejection port 23 is formed, and a second header part in which a discharge projection 210, the remainder of a second fuel ejection port 222, a flange portion 24, and a plurality of second air ejection ports 241 are formed. 2B are joined together. The second header part 2B is attached to the outer periphery of the base end side L2 in the axial direction L of the first header part 2A.

(Breathable member 26)
As shown in FIGS. 1 and 2, the air-permeable member 26 of this embodiment is made of metal knit formed by weaving a heat-resistant metal fiber material as a fiber material. The air-permeable member 26 is arranged to face the tapered outer surface 201 of the convex portion 22 of the inclined portion 211 of the nozzle portion 21 of the combustion header 2 . An end portion of the air-permeable member 26 on the proximal side L2 in the axial direction L is joined to a position on the distal side L1 in the axial direction L of the parallel portion 212 of the nozzle portion 21 by welding or the like.

The air-permeable member 26 may be made of metal or ceramics having a plurality of pores or voids that allow gas to pass through, in addition to the metal knit. The air-permeable member 26 may be made of, for example, glass wool made of a glass fiber material. Also, the air-permeable member 26 may be made of various materials that are heat-resistant, air-permeable, and nonflammable.

(Spark rod 5)
As shown in FIGS. 1 and 4, the spark rod 5 includes a central conductor portion 51 made of a conductive metal material, and an insulator portion 52 covering the outer periphery of the central conductor portion 51 and made of an insulating ceramic material. It is composed by The insulator portion 52 is not provided at the end portion of the center conductor portion 51 on the tip side L1 in the axial direction L. As shown in FIG. An end portion of the central conductor portion 51 on the tip side L1 in the axial direction L is exposed to the outside as a discharge rod end portion 511 . The central axis of the spark rod 5 is parallel to the central axes of the air tube 3 and the fuel tube 4 .

(Relationship between discharge rod end portion 511 and discharge convex portion 210)
As shown in FIGS. 1 to 4, the discharge projections 210 protrude outward in the radial direction R from the outer surface of the parallel portion 212 of the nozzle portion 21 of the combustion header 2 relative to the general portion of the parallel portion 212. formed. The discharge convex portion 210 is formed in a strip shape having a longer length in the circumferential direction C than the length in the axial direction L. As shown in FIG. With this configuration, even if the portion of the discharge convex portion 210 facing the discharge rod end portion 511 is worn by the discharge, both sides of the worn portion of the discharge convex portion 210 in the circumferential direction C A discharge can be generated between the site and the discharge rod end 511 . Therefore, discharge performance can be maintained for a long period of time.

As shown in FIG. 4, the width c of the discharge projection 210 in the axial direction L has a length of 3 to 5 mm. With this configuration, an appropriate discharge can be generated between the discharge rod end portion 511 and the discharge convex portion 210 . The length of the discharge protrusion 210 in the circumferential direction C may be greater than the width of the discharge protrusion 210 in the axial direction L, and may be 5 mm or more.

As shown in FIG. 3 , the discharge convex portion 210 of the present embodiment is formed continuously along the entire circumference in the circumferential direction C at the parallel portion 212 of the nozzle portion 21 . This configuration makes it easy to form the discharge projections 210 on the parallel portions 212 of the nozzle portion 21 . The outer surface in the radial direction R of the discharge convex portion 210 of this embodiment is formed parallel to the axial direction L along the circumferential direction C. As shown in FIG. The shape in the axial direction L of the outer surface in the radial direction R of the discharge convex portion 210 may be convex curved.

As shown in FIG. 4, in this embodiment, the distance b from the end surface 245 of the flange portion 24 on the distal side L1 in the axial direction L to the end surface 213 on the proximal side L2 of the discharge convex portion 210 in the axial direction L is , 6 to 12 mm. In addition, from the end surface 245 of the flange portion 24 on the distal end side L1 in the axial direction L, an end position 521 on the proximal end side L2 in the axial direction L of the discharge rod end portion 511 (the position on the distal end side L1 in the axial direction L of the insulator portion 52) The distance a to the end position 521) is set within the range of b−1 mm to b+2 mm with respect to the distance b.

In other words, the end position of the discharge rod end portion 511 on the proximal side L2 in the axial direction L is within 1 mm on the proximal side L2 in the axial direction L with respect to the position of the end face 213 in the axial direction L. It is set within a range of 2 mm on the tip side L1 in the axial direction L. With this configuration, an appropriate discharge can be generated between the discharge rod end portion 511 and the discharge convex portion 210 .

The end position 521 of the discharge rod end portion 511 on the base end side L2 in the axial direction L is shifted from the position of the end face 213 on the base end side L2 in the axial direction L of the discharge convex portion 210 to the base end side L2 in the axial direction L. When separated by more than 1 mm, the following is a concern. That is, not only between the discharge rod end portion 511 and the discharge convex portion 210, but also between the discharge rod end portion 511 and the parallel portion 212 located on the base end side L2 in the axial direction L from the discharge convex portion 210. Discharge may also occur between the general part of the

As shown in FIG. 4, the second fuel ejection port 222 is formed at a position closer to the distal end side L1 in the axial direction L than the position where the discharge convex portion 210 is formed in the general portion of the parallel portion 212 of the nozzle portion 21. there is The second fuel ejection port 222 of this embodiment is located at a position between the end position of the base end side L2 in the axial direction L of the air-permeable member 26 and the end face of the discharge convex portion 210 on the tip end side L1 in the axial direction L. formed.

(Combustion in surface combustion burner 1)
In the surface combustion burner 1 , the combustion header 2 guides the fuel gas F and the combustion air A through separate paths to just before the ventilation member 26 , so that the fuel gas F and the combustion air A pass through the ventilation member 26 . mixed combustion on the surface of When burning in the surface combustion burner 1, the fuel gas F passes through the fuel pipe 4, through the fuel passage 20 of the combustion header 2, and from the fuel passage 20, the plurality of first fuel injection ports 221 and the first The fuel is branched into two fuel ejection ports 222, ejected from the open ends of the fuel ejection ports 221 and 222 of the nozzle portion 21, and passes through the air-permeable member 26 from the inside to the outside in the radial direction R.

On the other hand, the combustion air A passes through the air pipe 3 to form a plurality of first air jets 23 in the nozzle portion 21 of the combustion header 2 and a plurality of second air jets in the flange portion 24 of the combustion header 2 . It branches to the exit 241 and flows. Combustion air A is ejected from the opening tips of the plurality of first air ejection ports 23 of the nozzle portion 21, passes through the air-permeable member 26 from the inside to the outside in the radial direction R, and passes through the plurality of flange portions 24. , and passes through the combustion header 2 toward the tip end side L1 in the axial direction L.

The fuel gas F ejected from the plurality of first fuel ejection ports 221 and the combustion air A ejected from the plurality of first air ejection ports 23 are arranged in the circumferential direction C near the surface of the air-permeable member 26 . mix with each other while moving to In the vicinity of the surface of the air-permeable member 26, the fuel gas F ejected from the plurality of first fuel ejection ports 221 and the combustion air A ejected from the plurality of first air ejection ports 23 contain a plurality of Combustion air A jetted from the second air jet port 241 is mixed. As a result, the fuel gas F and the combustion air A are sufficiently mixed in the vicinity of the surface of the air-permeable member 26, and the concentration of the fuel gas F in this air-fuel mixture is less likely to be uneven.

Further, the mixture of the fuel gas F and the combustion air A is ignited by a spark generated between the discharge rod end portion 511 of the spark rod 5 and the discharge convex portion 210 of the nozzle portion 21, It burns near the surface of the air-permeable member 26 and forms a flame inside the air pipe 3 . At this time, since the concentration of the fuel gas F in the air-fuel mixture is less likely to be uneven, the flame can be stably formed.

(Effect)
In the surface combustion burner 1 of this embodiment, the formation positions of the discharge rod end portion 511 of the spark rod 5 and the discharge convex portion 210 of the nozzle portion 21 are devised. Specifically, a discharge convex portion 210 is formed at a position facing the discharge rod end portion 511 in the radial direction R on the outer surface of the parallel portion 212 of the nozzle portion 21 . Further, the discharge rod end portion 511 is arranged at a position facing the discharge convex portion 210 in the radial direction R. As shown in FIG. Further, the plurality of first fuel ejection ports 221 and the second fuel ejection ports 222 are formed on the tip side L1 in the axial direction L from the formation position of the discharge convex portion 210 .

With these configurations, the fuel gas F ejected from the plurality of first fuel ejection ports 221 of the nozzle portion 21, the plurality of first air ejection ports 23 of the nozzle portion 21, and the plurality of second air ejection ports of the flange portion 24 When the air-fuel mixture with the combustion air A jetted from 241 is combusted, it is possible to make it difficult for the flame due to combustion in the vicinity of the surface of the gas-permeable member 26 to come into contact with the discharge rod end 511 . As a result, the spark rod 5 is less likely to be heated, and deformation due to overheating during ignition of the spark rod 5 can be suppressed.

Further, in this embodiment, even in a configuration in which the discharge rod end portion 511 is shifted toward the base end side L2 in the axial direction L from the flame formation position by forming the second fuel ejection port 222, ignition by the spark rod 5 is possible. Defects are prevented from occurring. In addition, due to the configuration of the strip-shaped discharge projections 210 that are elongated in the circumferential direction C, the ignition performance of the spark rod 5 is maintained for a long period of time.

Therefore, according to the surface combustion burner 1 of this embodiment, the durability of the discharge rod end portion 511 of the spark rod 5 can be improved.

The present invention is not limited to only the embodiments, and further different embodiments can be configured without departing from the scope of the invention. In addition, the present invention includes various modifications, modifications within the equivalent range, and the like.

REFERENCE SIGNS LIST 1 surface combustion burner 2 combustion header 21 nozzle portion 210 discharge convex portion 211 inclined portion 212 parallel portion 221 first fuel ejection port 222 second fuel ejection port 23 first air ejection port 24 flange portion 241 second air ejection port 26 Breathable member 3 Air pipe 4 Fuel pipe 5 Spark rod 511 Discharge rod end

Claims (4)

an air pipe through which combustion air passes;
a fuel pipe disposed within the air pipe through which fuel gas passes;
Combustion fuel pipe having a nozzle portion and a flange portion provided at the proximal end side of the nozzle portion in the axial direction, the nozzle portion being connected to the distal end side in the axial direction along the central axis of the fuel pipe and disposed in the air pipe. a header;
an air-permeable member provided on the outer surface of the nozzle portion and formed of a fibrous material or a porous material;
a spark rod disposed through the flange portion and having a discharge rod end disposed at a position facing the outer surface of the nozzle portion;
The nozzle portion is formed with a plurality of fuel ejection ports for ejecting the fuel gas and a plurality of first air ejection ports for ejecting the combustion air, and the flange portion is formed with: A plurality of second air ejection ports are formed for ejecting the combustion air,
A discharge projection is formed at a position facing the discharge rod end on the outer surface of the nozzle portion on the base end side in the axial direction,
The surface combustion burner, wherein the plurality of fuel injection ports are formed on the tip end side in the axial direction from the formation position of the discharge convex portion. 2. The surface combustion burner according to claim 1, wherein said discharge convex portion is formed in a belt shape having a longer circumferential length around the central axis of said fuel tube than said axial length. The plurality of fuel ejection ports include a plurality of first fuel ejection ports formed at a plurality of locations in the axial direction of the nozzle portion and in a circumferential direction around the central axis of the fuel pipe, and a plurality of the first fuel ejection ports. Disposition of the discharge rod end portion in the circumferential direction on the base end side in the axial direction from the formation position of the outlet, on the distal end side in the axial direction from the formation position of the discharge convex portion. 3. The surface combustion burner according to claim 1, further comprising a second fuel jet formed at a position overlapping the position. The nozzle portion has a parallel portion that is parallel to the axial direction, and a portion that is located on the distal end side of the parallel portion in the axial direction and has a diameter centered on the central axis of the fuel pipe toward the distal end side in the axial direction. a slanted portion having a reduced dimension in a direction and having the breathable member disposed thereon;
4. The surface combustion according to any one of claims 1 to 3, wherein the discharge convex portion is formed continuously around the central axis of the fuel pipe at the parallel portion in the circumferential direction. burner.

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