burner

Abstract

To provide a burner that further suppresses the generation of unburned fuel. [Solution] The burner 1 comprises an inner cylinder 4 and an outer cylinder 2 provided radially outward from the inner cylinder 4. The outer cylinder 2 has an outer cylinder base end 10 in which a first combustion chamber C1 is formed radially inward, an outer cylinder central part 12 in which a second combustion chamber C2 is formed radially inward, and an outer cylinder tip 14 in which a third combustion chamber C3 is formed radially inward. The inner cylinder 4 is positioned in the first combustion chamber C1. The diameter of the outer cylinder central part 12 is larger than the diameter of the outer cylinder base end 10. The diameter of the outer cylinder tip 14 is smaller than the diameter of the outer cylinder central part 12. The inner cylinder 4 has an inner cylinder base end 20, an inner cylinder tip 22, and a partition 24. The inner cylinder base end 20 has a gas injection hole 20G that releases gas G radially outward. The partition 24 prevents gas G in the inner cylinder base end 20 from flowing into the inner cylinder tip 22. The inner cylinder tip 22 and the partition 24 are bowl-shaped.

Description

Technical Field

[0004] , , , ,

[0001] The present invention relates to a burner capable of burning a low-flammability fuel such as ammonia, which has a lower flammability than hydrocarbon-based fuels.

Background Art

[0002] Even when attempting to burn a low-flammability fuel such as ammonia in a burner for a highly flammable hydrocarbon-based fuel, due to differences in combustion speed, flammable range, and ignition speed, the flame formed in the combustion chamber becomes unstable, and there is a relatively high possibility that stable continuous combustion (flame retention) cannot be achieved, and there is also a relatively high possibility that a phenomenon (unburned) occurs where a part of the fuel remains unburned. As a conventional burner capable of continuously burning a low-flammability fuel, the one described in Japanese Unexamined Patent Application Publication No. 2023-106203 (Patent Document 1) is known. This burner includes a gas nozzle body having a gas ejection hole for ejecting a gas such as ammonia radially outward, and a partition portion disposed at the tip of the gas nozzle body. The partition portion has a roof portion that projects radially outward. Further, in this burner, a cylindrical rectifying mechanism body in a rectifying mechanism for rectifying the primary air for burning the gas is disposed radially outward of the gas nozzle body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above burner, there is room for improvement in suppressing unburned. Therefore, the main object of the present invention is to provide a burner in which the occurrence of unburned is further suppressed.

Means for Solving the Problems

[0005] This specification discloses a burner. The burner may include an inner cylinder 4 through which a gas G passes. The burner may include an outer cylinder 2 provided radially outward from the inner cylinder 4, through which air passes. The outer cylinder 2 may have an outer cylinder base end 10 through which a first combustion chamber C1 is formed radially inward. The outer cylinder 2 may have an outer cylinder central portion 12 through which a second combustion chamber C2 is formed radially inward. The outer cylinder 2 may have an outer cylinder tip end 14 through which a third combustion chamber C3 is formed radially inward. The inner cylinder 4 may be positioned in the first combustion chamber C1. The diameter of the outer cylinder central portion 12 may be larger than the diameter of the outer cylinder base end 10. The diameter of the outer cylinder tip end 14 may be smaller than the diameter of the outer cylinder central portion 12. The inner cylinder 4 may have an inner cylinder base end 20. The inner cylinder 4 may have an inner cylinder tip end 22. The inner cylinder 4 may have a partition portion 24. The base end portion 20 of the inner cylinder may have a gas ejection hole 20G that releases gas G radially outward. The partition portion 24 may prevent gas G in the base end portion 20 of the inner cylinder from flowing into the tip portion 22 of the inner cylinder. The tip portion 22 of the inner cylinder and the partition portion 24 may be bowl-shaped. [Effects of the Invention]

[0006] The present invention provides a burner in which the generation of unburned fuel is further suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This is an external view of a burner according to an embodiment of the present invention. [Figure 2] This is a central longitudinal cross-section of the burner in Figure 1. [Figure 3] Figure 3A is a central longitudinal cross-sectional view of the tip of the outer cylinder of the burner according to Example 1, Figure 3B is a central longitudinal cross-sectional view of the tip of the outer cylinder of the burner according to Example 2, and Figure 3C is a central longitudinal cross-sectional view of the tip of the outer cylinder of the burner according to Example 3. [Modes for carrying out the invention]

[0008] Examples of embodiments and modifications thereof according to the present invention will be described below with reference to the drawings as appropriate. However, these embodiments are not limited to the examples and modifications described below.

[0009] Figure 1 is an external view of the burner 1 according to the said configuration. Figure 2 is a central longitudinal cross-sectional view of the burner 1. The burner 1 has an outer cylinder 2, an inner cylinder 4, and a plug 6. Burner 1 is installed relative to the furnace such that at least its tip enters the interior of the furnace (not shown) or a portion connected to the furnace (not shown). In this case, the burner 1 is positioned horizontally, with the tip end on the right and the base end on the left. The longitudinal direction of the burner 1 (from tip end to base end) is horizontal. The position of the burner 1 can be changed in various ways, for example, to a position where it extends vertically with the top end being the tip.

[0010] The outer cylinder 2 is made of metal and is a cylindrical component. The virtual central axis of the outer cylinder 2 runs along its longitudinal direction and is the central axis of the burner 1. The outer cylinder 2 may also be of other cylindrical shapes, such as a regular polygonal cylinder. The same applies to other cylindrical components. Furthermore, the material of the outer cylinder 2 may be something other than metal, such as ceramics. The materials of other components and parts of the burner 1 can also be changed in various ways in a similar manner. The outer cylinder 2 has an outer cylinder base portion 10, an outer cylinder central portion 12, a plurality (8) of fins 13, and an outer cylinder tip portion 14.

[0011] The outer cylinder base end portion 10 is located on the base end side of the outer cylinder 2. The tip of the outer cylinder base end portion 10 is the first combustion chamber C1. The central part 12 of the outer cylinder is located between the base end 10 and the tip 14 of the outer cylinder. The inner diameter of the central part 12 is larger than the inner diameter of the base end 10 of the outer cylinder. The inside of the central part 12 is the second combustion chamber C2. The outer diameter of the central part 12 is larger than the outer diameter of the base end 10 of the outer cylinder. Each fin 13 is positioned on the outer surface of the central portion 12 of the outer cylinder. Each fin 13 protrudes radially outward from the outer surface of the central portion 12 of the outer cylinder in a flange-like manner. The number of fins 13 may be one, two to seven, or nine or more. The number of other members and parts can also be varied in a similar manner. Furthermore, some or all of the fins 13 may be provided on the outer surface of the outer cylinder 2 other than the central portion 12 of the outer cylinder. The outer cylinder tip 14 is located at the front end of the outer cylinder 2. The inner diameter of the outer cylinder tip 14 is smaller than the inner diameter of the outer cylinder center 12. The inside of the outer cylinder tip 14 is the third combustion chamber C3. The outer diameter of the outer cylinder tip 14 is smaller than the outer diameter of the outer cylinder center 12. The inner diameter of the outer cylinder tip 14 is smaller than the inner diameter of the outer cylinder base 10. The outer diameter of the outer cylinder tip 14 is the same as the outer diameter of the outer cylinder base 10. Furthermore, the inner diameter of the outer cylinder tip 14 may be the same as the inner diameter of the outer cylinder base 10, or it may be larger than the inner diameter of the outer cylinder base 10. Also, the outer diameter of the outer cylinder tip 14 may be smaller than the outer diameter of the outer cylinder base 10, or it may be larger than the outer diameter of the outer cylinder base 10.

[0012] An air supply port AS, a gas supply port GS, and a UV monitoring device connection part UJ are formed at the base end of the outer cylinder base end 10. An air tube (not shown) is connected to the air supply port AS to supply air A. The air supply port AS is connected between the inner cylinder 4 and the outer cylinder 2. Air A flows between the inner cylinder 4 and the outer cylinder 2. Air A passes between the inner cylinder 4 and the outer cylinder 2. Air A is air in this case. A gas supply tube (not shown) is connected to the gas supply port GS to supply gas G. The gas supply port GS is connected to the inside of the inner cylinder 4. In this case, gas G is ammonia. Gas G flows inside the inner cylinder 4. Gas G passes through the inside of the inner cylinder 4. A UV monitoring device (not shown) is connected to the UV monitoring device connection section UJ. The UV monitoring device receives ultraviolet (UV) light from the combustion flame F and monitors the combustion state by analyzing the presence, degree, and pattern of UV light.

[0013] The inner cylinder 4 has a gas nozzle function for ejecting the gas G, an air guiding function for guiding the air A which is a gas for burning the gas G, and an air-fuel mixture adjusting function for adjusting the flow of the air-fuel mixture of the gas G and the air A. Incidentally, some or all of these functions may be exerted by other components than the inner cylinder 4. The inner cylinder 4 has an inner cylinder base end portion 20, a support portion 21, an inner cylinder tip end portion 22, and a partition portion 24.

[0014] The inner cylinder base end portion 20 is made of metal and is cylindrical with openings at the tip end and the base end respectively. The inner cylinder base end portion 20 has a plurality (8) of gas ejection holes 20G. The gas ejection holes 20G are arranged in a state of being aligned in the circumferential direction at the tip end portion of the inner cylinder base end portion 20. Incidentally, the number of the gas ejection holes 20G may be 1, or may be 2 or more and 7 or less, or may be 9 or more.

[0015] The support portion 21 is made of metal, is in a flange shape, and protrudes radially outward from the outer surface of the central portion of the inner cylinder base end portion 20. The radially outer surface of the support portion 21 is in contact with the inner surface of the outer cylinder base end portion 10. The support portion 21 supports the inner cylinder 4 with respect to the outer cylinder base end portion 10 and positions the inner cylinder 4 within the first combustion chamber C1. The virtual central axis of the inner cylinder 4 coincides with the virtual central axis of the outer cylinder 2. The inner cylinder 4 is coaxial with the outer cylinder 2. The support portion 21 is integral with the inner cylinder base end portion 20. The support portion 21 has air passage holes 21A for passing the air A. The air passage holes 21A are arranged in a state of being aligned in the circumferential direction. Incidentally, the number of the air passage holes 21A may be 1, or may be 2 or more and 7 or less, or may be 9 or more. Also, the support portion 21 may be separate from the inner cylinder base end portion 20 and may be attached to the inner cylinder base end portion 20. Changes in the integrated or separate mode and changes in the splitting mode of the members can be similarly made in other members and parts of the burner 1. Further, the outer cylinder 2 and the inner cylinder 4 may not be coaxial with each other in part or in whole.

[0016] The tip portion 22 of the inner cylinder is made of metal and is cylindrical with openings at the tip and the base end. The tip portion 22 of the inner cylinder is integral with the base end portion 20 of the inner cylinder. The tip portion 22 of the inner cylinder has a ring-shaped joint portion 22J and a cylindrical wall portion 22W. The joint portion 22J is connected to the tip of the base end portion 20 of the inner cylinder and extends radially outward from the tip of the base end portion 20 of the inner cylinder. The wall portion 22W protrudes from the radially outer edge of the joint portion 22J toward the tip side and surrounds the tip side of the joint portion 22J. Incidentally, the tip portion 22 of the inner cylinder may be separate from the base end portion 20 of the inner cylinder and may be attached to the base end portion 20 of the inner cylinder. Also, the joint portion 22J may be treated as a component of the base end portion 20 of the inner cylinder or may be treated as an independent component.

[0017] The partition portion 24 partitions the inside of the base end portion 20 of the inner cylinder and the inside of the tip portion 22 of the inner cylinder. The partition portion 24 stops the inflow of the gas G inside the base end portion 20 of the inner cylinder into the tip portion 22 of the inner cylinder. The partition portion 24 is attached to the tip side of the joint portion 22J. The partition portion 24 is disk-shaped. Incidentally, the shape of the partition portion 24 may be other shapes such as having at least one of a regular polygonal plate shape and a flat plate shape. The shapes of other members and parts in the burner 1 can also be similarly changed in various ways. Also, the partition portion 24 may be attached to the base end side of the joint portion 22J. The arrangements of other members and parts in the burner 1 can also be similarly changed in various ways. The partition portion 24 has a light-transmitting plate 30 and a plurality (two) of packings 32. The light-transmitting plate 30 is plate-shaped and has UV light-transmitting properties that allow UV to pass through. The light-transmitting plate 30 is made of quartz glass. Also, the light-transmitting plate 30 has visible light-transmitting properties that allow visible light to pass through. Incidentally, the material of the light-transmitting plate 30 may be other materials. Also, the light-transmitting plate 30 may have only one of the UV light-transmitting property and the visible light-transmitting property, or may not have both. When it does not have both the UV light-transmitting property and the visible light-transmitting property, the light-transmitting plate 30 becomes a partition plate. Each packing 32 is a ring-shaped elastic body. The inner diameter of each packing 32 is the same as the inner diameter of the base end 20 of the inner cylinder and the inner diameter of the joint 22J. The outer diameter of each packing 32 is the same as the inner diameter of the tip end 22 of the inner cylinder and the outer diameter of the joint 22J. The packings 32 are positioned on the tip and base ends of the light-transmitting plate 30, sandwiching the light-transmitting plate 30. Each packing 32 airtightly attaches the light-transmitting plate 30 to the tip end 22 of the inner cylinder. Note that some or all of each packing 32 may be omitted.

[0018] The portion radially inward of the inner cylinder base end 20, and closer to the tip of the partition 24, becomes the first combustion chamber C1. The inner cylinder tip 22 and partition 24 form a bowl-shaped portion B. The inner cylinder 4 becomes a gas nozzle with the bowl-shaped portion B at its tip. The bowl-shaped portion B is open towards the tip and closed at the base. A gas ejection hole 20G is located on the base side of the bowl-shaped portion B in the inner cylinder 4. The gas G emitted from the gas ejection hole 20G mixes with the air A that has passed through the air passage hole 21A and flows further toward the tip as an introduction flow E. The burner 1 is a nozzle mix type that obtains the air-fuel mixture within the inner cylinder base end 20 inside the outer cylinder base end 10. The introduction flow E increases in velocity as it moves from the outside of the inner cylinder base end 20 to the outside of the narrower inner cylinder tip end 22, being pushed radially outward from the outer cylinder 2, and enters the first combustion chamber C1. A portion of the introduction flow E that enters the first combustion chamber C1 becomes a swirling flow T that moves toward the tip while circling around the central axis of the burner 1. Another portion of the introduction flow E that enters the first combustion chamber C1 becomes a return flow R that returns toward the base end at the tip side of the bowl-shaped section B.

[0019] The swirling flow T rotates counterclockwise when viewed from the tip. However, the direction of rotation of the swirling flow T may be in other directions, such as a clockwise inclination when viewed from the tip. As the swirling flow T enters the larger diameter second combustion chamber C2 from the first combustion chamber C1, its velocity towards the tip decreases. Furthermore, when the swirling flow T enters the smaller diameter third combustion chamber C3 from the second combustion chamber C2, its velocity toward the tip increases, and it becomes a straight flow H towards the tip of the burner 1. The swirling flow T is given straightness in the third combustion chamber C3 and becomes a straight flow H. The size of the inner diameter of the tip portion 14 of the outer cylinder, that is, the radial size of the third combustion chamber C3, is related to the discharge velocity of the straight flow H. If the radial size of the third combustion chamber C3 is large, the discharge velocity of the straight flow H will be slower, and if the radial size of the third combustion chamber C3 is small, the discharge velocity of the straight flow H will be faster.

[0020] On the other hand, the characteristics of the return flow R vary depending on various conditions such as the respective flow velocities of air A and gas G, the size of the outer diameter of the bowl-shaped section B, the difference between the outer diameter of the bowl-shaped section B and the outer diameter of the inner cylinder base end 20, and the longitudinal size of the wall section 22W. Under normal conditions where the combustion of gas G continues, it becomes a swirling type. The swirling type return flow R moves radially inward, approaching the central axis of the burner 1, so as to enter the bowl-shaped section B from the radially outward side of the first combustion chamber C1, and then returns to the base end side, flowing radially outward and towards the tip side within the bowl-shaped section B in a swirling manner, and merges with the swirling flow T. The bowl-shaped section B strongly promotes such a swirling type return flow R. Furthermore, by adjusting at least one of the above conditions, the ratio of the flow rates of the swirling flow T to the return flow R, and at least one of the flow path shapes (including size as appropriate) of the return flow R can be adjusted. For example, increasing the outer diameter of the bowl-shaped section B increases the magnitude of the meandering of the return flow R, resulting in a greater flow rate for the return flow R, and also increasing the size of the return vortex flow path shape in the return flow R. Essentially, all of the return flow R remains within the first combustion chamber C1.

[0021] The plug 6 is connected to a power line (not shown) and is capable of generating a spark at its tip. The plug 6 is attached to the tip end of the inner cylinder base end 20. The tip of the plug 6 is located inside the first combustion chamber C1. The tip of the plug 6 is located radially outward from the wall portion 22W of the inner cylinder tip end 22. Burner 1 is a direct ignition type that can be ignited directly by a spark via plug 6.

[0022] The swirling flow T and straight flow H, as well as the return flow R, of the gas G mixed with air A are ignited by the spark plug 6 and burn in the first combustion chamber C1, the second combustion chamber C2 to the third combustion chamber C3. Due to the return flow R, the gas G continues to burn in the first combustion chamber C1 even without a continuous spark at the plug 6. Therefore, the pilot flame is maintained in the first combustion chamber C1, and the flame retention of the burner 1 is achieved. Furthermore, the second combustion chamber C2, which has a larger diameter than the first combustion chamber C1 and the third combustion chamber C3, causes the velocity of the swirling flow T to settle down temporarily. In other words, the flow of the air-gas mixture from the second combustion chamber C2 to the third combustion chamber C3 is subjected to a load, making it easier for the mixture to temporarily remain in the second combustion chamber C2 and for heat to be retained more easily through combustion of the mixture. Therefore, combustion of gas G is carried out sufficiently in the second combustion chamber C2, and unburned gas G is suppressed. The temperature inside the second combustion chamber C2 is preferably kept above 651°C, which is the ignition temperature of ammonia, and more preferably above 800°C, with a margin above the ignition temperature of ammonia. Furthermore, the swirling flow T, which increases in velocity from the second combustion chamber C2 to the third combustion chamber C3, becomes a straight flow H at the tip of the third combustion chamber C3. This causes the gas G that did not burn in the first combustion chamber C1 and the second combustion chamber C2 to burn, thus suppressing unburned gas G. A combustion flame F is formed at the tip end of the third combustion chamber C3, from tip to tip end of the outer cylinder 2. The combustion flame F is stabilized when the mixture of air A and gas G becomes a straight flow H at the base end adjacent to the outlet at the tip of the outer cylinder 2. In order to obtain a sufficient straight flow H from a swirling flow T, preferably the longitudinal length of the third combustion chamber C3 is 3D or more, where D is the radial size (diameter) of the third combustion chamber C3.

[0023] Monitoring of the combustion state, such as the combustion flame F in burner 1, can be performed from the base end side by a UV monitoring device connected to the UV monitoring device connection part UJ via a UV-transmitting plate 30. Furthermore, because the light-transmitting plate 30 is made of quartz glass, a light-transmitting plate 30 that is both heat-resistant and UV-transmitting can be manufactured at a lower cost.

[0024] Furthermore, because each fin 13 is provided on the outer cylinder 2, the outer surface temperature of the radial outer edge portion of each fin 13 is lower than the outer surface temperature of the outer cylinder 2 if the fins 13 were not provided. Therefore, the handling of the burner 1 is improved.

[0025] The burner 1 described above comprises an inner cylinder 4 through which gas G passes, and an outer cylinder 2 provided radially outward from the inner cylinder 4, through which air A passes between the outer cylinder 4 and the inner cylinder 4. The outer cylinder 2 has an outer cylinder base end 10 through which a first combustion chamber C1 is formed radially inward, an outer cylinder central part 12 through which a second combustion chamber C2 is formed radially inward, and an outer cylinder tip 14 through which a third combustion chamber C3 is formed radially inward. The inner cylinder 4 is positioned in the first combustion chamber C1. The diameter of the outer cylinder central part 12 is larger than the diameter of the outer cylinder base end 10. The diameter of the outer cylinder tip 14 is smaller than the diameter of the outer cylinder central part 12. The inner cylinder 4 has an inner cylinder base end 20, an inner cylinder tip 22, and a partition 24. The inner cylinder base end 20 has a gas ejection hole 20G through which gas G is released radially outward. The partition 24 prevents gas G from the base end 20 of the inner cylinder from flowing into the tip 22 of the inner cylinder. The tip 22 of the inner cylinder and the partition 24 are bowl-shaped. Therefore, the bowl-shaped section B within the first combustion chamber C1 forms a return flow R of the fuel-air mixture to maintain the pilot flame, improving the flame retention of the burner 1. Furthermore, the expansion of the diameter from the first combustion chamber C1 to the second combustion chamber C2 reduces the flow velocity of the swirling flow T of the fuel-air mixture, and the reduction in diameter from the second combustion chamber C2 to the third combustion chamber C3 creates a load on the fuel-air mixture. As a result, the second combustion chamber C2 retains heat more easily, promoting combustion of the fuel-air mixture in the second combustion chamber C2, suppressing unburned fuel in the burner 1, and improving flame retention. Moreover, the reduction in diameter from the second combustion chamber C2 to the third combustion chamber C3 promotes the conversion from the swirling flow T to the straight flow H, forming a larger combustion flame F and suppressing unburned fuel-air mixture. As a result, the combustion mainly maintained in the first combustion chamber C1, temporarily lingering in the second combustion chamber C2, is guided directly into the third combustion chamber C3 by the mixture, forming a combustion flame F of a predetermined size or larger, and spreading smoothly from the second combustion chamber C2 to the third combustion chamber C3. Therefore, a burner 1 is provided in which the generation of unburned fuel is further suppressed.

[0026] Furthermore, the partition 24 includes a light-transmitting plate 30. Therefore, when observing from the base end, the tip side of the partition 24 becomes visible, and if a UV monitoring device is connected to the base end, automatic monitoring of the combustion flame F becomes possible. Furthermore, the light-transmitting plate 30 is made of quartz glass. Therefore, a light-transmitting plate 30 with excellent heat resistance, strength, and light transmittance can be constructed at a low cost.

[0027] In addition, the longitudinal length of the third combustion chamber C3 is set to be at least three times the diameter of the third combustion chamber C3. Therefore, the conversion from swirling flow T to straight flow H is more effectively promoted. Furthermore, the discharge velocity of the gas G and air A mixture exiting from the third combustion chamber C3 towards the tip is 25 m / s or less. Therefore, the occurrence of situations where the formation of the combustion flame F is interrupted due to an excessively high discharge velocity is further suppressed.

[0028] Furthermore, the temperature inside the second combustion chamber C2 is maintained at 651°C or higher. Therefore, especially when gas G is ammonia, the temperature inside the second combustion chamber C2 exceeds the ammonia ignition temperature, further promoting combustion. Furthermore, the outer cylinder 2 has fins 13 that protrude radially outward. Therefore, the temperature of the outermost radial portion of the outer cylinder 2 is lower compared to the case without the fins 13. Consequently, the handling of the burner 1 is improved. In addition, the first combustion chamber C1 is equipped with a spark plug 6 capable of generating a spark. Thus, a burner 1 capable of direct ignition is provided.

[0029] Furthermore, the above forms and examples of modifications may be further modified as appropriate. Gas G can be anything other than ammonia. Air A may be something other than air. Multiple burners 1 may be installed in a single furnace. In this case, the configurations of at least two of the burners 1 may differ from each other. The use of burner 1 and the furnace is not particularly limited and can be, for example, for ceramics, drying, etc. [Examples]

[0030] Next, Examples 1 to 3 of the present invention will be described. Examples 1 to 3 are in accordance with the embodiments described above. Furthermore, the present invention is not limited to the following examples. Depending on how the present invention is interpreted, some examples may be comparative examples that do not belong to the present invention.

[0031] Figure 3A is a central longitudinal cross-sectional view of the outer cylinder tip 14 of the burner 1 according to Example 1. Figure 3B is a central longitudinal cross-sectional view of the outer cylinder tip 14 of the burner 1 according to Example 2. Figure 3C is a central longitudinal cross-sectional view of the outer cylinder tip 14 of the burner 1 according to Example 3.

[0032] In Example 1, the radial size (diameter) of the second combustion chamber C2 is 44 mm, and the radial size (diameter) of the third combustion chamber C3 is 24 mm. In Example 1, the longitudinal size of the third combustion chamber C3 is 3D, or 72 mm. In Example 1, the air ratio (flow rate ratio) of the ammonia-air mixture is 1.0.

[0033] Example 2 is the same as Example 1, except that the radial size (diameter) of the third combustion chamber C3 is 20 mm, which is smaller than that of Example 1. The longitudinal size of the third combustion chamber C3 in Example 2 is 3D, or 60 mm.

[0034] Example 3 is the same as Example 1, except that the radial size of the third combustion chamber C3 is smaller at the tip. The radial size (diameter) of the base portion of the third combustion chamber C3 is 20 mm, and the radial size (diameter) of the tip portion of the third combustion chamber C3 is 15 mm. The longitudinal size of the base portion of the third combustion chamber C3 is 2D, or 40 mm, and the longitudinal size of the tip portion of the third combustion chamber C3 is 20 mm.

[0035] Regarding the discharge velocity of the mixed gas at the tip of the outer cylinder 2, the discharge velocity in Example 1 was 15 m / s (meters per second), the discharge velocity in Example 2 was 22 m / s, and the discharge velocity in Example 3 was 35 m / s. Then, when the concentration of unburned ammonia was measured adjacent to the combustion flame F, it was 1.7 ppm in Example 1, 1.6 ppm in Example 2, and 19 ppm in Example 3.

[0036] In view of Examples 1 and 2 relative to Example 3, it is preferable that the discharge velocity of the mixture be 25 m / s or less, and more preferably 15 m / s or more. Furthermore, in view of Examples 1 and 2 with respect to Example 3, it is preferable that the radial size of the third combustion chamber C3 is constant throughout its entire longitudinal direction. In other words, it is preferable that the inner diameter of the outer cylinder tip portion 14 is constant. [Explanation of symbols]

[0037] 1. Burner 2. Outer cylinder 4 Inner cylinder 6 plugs 10. Outer cylinder base end 12. Outer cylinder center 13. Finn 14. Outer cylinder tip 20 Inner cylinder base end 20G Gas vent 22. Inner cylinder tip 24. Partition section 30... Translucent plate B. Bowl-shaped part C1 ··First Combustion Chamber C2 ·· Second Combustion Chamber C3 · Third Combustion Chamber D. Diameter of the third combustion chamber H...Straight flow T...Swirling flow

Claims

1. An inner cylinder through which gas passes, An outer cylinder provided radially outward of the inner cylinder, through which air passes between it and the inner cylinder. It is equipped with, The outer cylinder has a cylindrical base end portion in which a first combustion chamber is formed radially inward, a cylindrical central portion in which a second combustion chamber is formed radially inward, and a cylindrical tip portion in which a third combustion chamber is formed radially inward. The inner cylinder is positioned in the first combustion chamber. The inner diameter of the central part of the outer cylinder is larger than the inner diameter of the base end of the outer cylinder. The inner diameter of the tip of the outer cylinder is smaller than the inner diameter of the central part of the outer cylinder. The inner cylinder has an inner cylinder base end, an inner cylinder tip, and a partition. The base end of the inner cylinder has a gas ejection hole for releasing the gas radially outward. The partition prevents the gas in the base end of the inner cylinder from flowing into the tip end of the inner cylinder. The tip of the inner cylinder and the partition are bowl-shaped. The tip of the inner cylinder is cylindrical. A burner characterized by the following features.

2. The partition section includes a light-transmitting plate. The burner according to feature 1.

3. The light-transmitting plate is made of quartz glass. The burner according to feature 2.

4. The longitudinal length of the third combustion chamber is set to be at least three times the diameter of the third combustion chamber. The burner according to feature 1.

5. The discharge velocity of the gas-air mixture exiting the third combustion chamber towards the tip is 25 m / s or less. The burner according to feature 1.

6. The temperature inside the second combustion chamber is maintained at 651°C or higher. The burner according to feature 1.

7. The outer cylinder has fins that protrude radially outward. The burner according to feature 1.

8. Furthermore, the first combustion chamber is equipped with a spark plug capable of generating a spark. The burner according to feature 1.

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