JP7715385B2 - Burner for heating tube body - Google Patents

Description

The present invention relates to a tube heating burner used to remove tubes, such as water tubes in a boiler, when replacing them, and to a method for removing tubes from a boiler.

Boilers generally employ a structure in which pipes such as water tubes are connected to a support wall member such as a drum. Furthermore, during boiler repairs and maintenance, the pipes must be removed from the support wall member and replaced. Therefore, a conventional connection structure has been employed in which the open end of the pipe is inserted into a mounting hole formed in the support wall member and then fitted and fixed by expanding the diameter. With this type of pipe connection structure, unlike connection structures using welding or other methods, the pipe is fixed as a separate member rather than being integrated with the support wall member, making it easier to remove the pipe.

Specifically, as shown in the conventional example in Figure 13, a commonly used method is to use a hammer or similar device to apply an external force to the open end of the tube protruding from the mounting hole, thereby deforming the open end of the fitted and fixed tube and removing it from the mounting hole. This method can be implemented using simple mechanical equipment and also reduces implementation costs.

However, when deforming the open end of the tube inward, it is difficult to avoid damage to the support wall member caused by contact with the hammer device or other device, and the support wall member is particularly susceptible to damage around the opening edge of the mounting hole, which is important for ensuring a tight seal at the joint between the tube and the support wall member.

Furthermore, for example, if the support wall member is thick and the length of the portion of the pipe that is inserted and fixed to the support wall member is long, it may be difficult to sufficiently reduce the fixing force of the pipe to the support wall member simply by deforming the open end of the pipe, making it impossible to remove the pipe.

In recent years, therefore, a method for removing a tube using high-frequency induction heating has also been proposed. Specifically, a coil is inserted into the open end of a tube that has been inserted and fixed to a support wall member, and a high-frequency voltage is applied to the coil, heating the entire open end of the tube located around the coil using high-frequency induction heating. The open end of the tube is then cooled after heating, causing it to shrink in diameter through thermal contraction, reducing the fastening force between the tube and the support wall member, allowing the tube to be removed from the support wall member. Removing a tube using high-frequency induction heating in this way avoids damage to the support wall member, particularly around the opening periphery of the mounting hole.

However, high-frequency induction heating requires large-scale equipment, and the preparations and electrical operating control settings for each boiler are difficult and require specialized knowledge, making it difficult to implement. Furthermore, due to the above-mentioned reasons, the costs involved in implementation are high, making it difficult to adopt in many cases.

The objective of this invention is to provide a tube heating burner with a novel structure that can easily heat tubes in a short amount of time.

Another object of the present invention is to provide a novel method for removing a tube from a boiler, which allows for easy and quick removal of a tube whose open end is inserted and fixed through a mounting hole in a boiler drum while minimizing the risk of damaging the drum and also reduces implementation costs.

The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is provided as an example and may be combined with one another as appropriate. Furthermore, the multiple components described in each embodiment may be recognized and employed independently to the greatest extent possible, and may also be combined with any of the components described in other embodiments as appropriate. As a result, the present invention is not limited to the embodiments described below, and various alternative embodiments may be realized.

To solve the above-mentioned problems, the inventor first investigated the heating of a tube using a burner of conventional construction. A burner generally has a nozzle at its tip that ejects combustion gas, forming a flame toward the tip, as shown in Figure 14. An operator then inserts the tip of the burner into the open end of the tube and heats it by blowing the flame against the inner surface of the tube.

However, with conventional burners, only one point on the tube is heated, and it has become clear that heating takes a long time when a wide circumferential range of the tube needs to be heated. Furthermore, in order to heat a wide area of the tube using a conventional burner, the operator must move the burner, making the heating process tedious and difficult. Furthermore, with conventional burners, the tip where the flame is generated must be directed toward the inner surface of the tube, and the tip is inserted at an angle relative to the tube's central axis. Therefore, with small-diameter tubes, even inserting the tip into the tube in the appropriate orientation can be difficult. Of these multiple issues, the long time required for heating is particularly problematic. Long heating times can lead to concerns that the work environment may deteriorate due to radiant heat, that increased thermal diffusion due to heat transfer may further reduce heating efficiency, and that heat transfer may have a negative impact on the support wall member.

As a result of further investigation into heating with such a tube heating burner, the present invention was arrived at. A first aspect of the present invention is a tube heating burner, in which the combustion gas outlets in the tip nozzle part of the burner body are not open in the axial direction of the tip nozzle part, but are located at multiple locations in the circumferential direction on the outer circumferential surface of the tip nozzle part and are opened toward the outer periphery , and in the burner body, the tip nozzle part is provided at the tip of a gas pipe through which premixed combustion gas is introduced, and the gas pipe has a curved part in the middle part in the longitudinal direction, and a cylindrical cooling jacket that covers the outer periphery of the gas pipe and forms a cooling cavity on the outer circumferential surface of the gas pipe extends from the tip nozzle part to the base end side, and the cooling jacket is a base-side tubular portion and a tip-side tubular portion extending linearly from the curved portion to the base-side and tip-side in the length direction, respectively, and connected to each other on the outer periphery of the curved portion; the cooling cavity is formed from the curved portion of the gas pipe to both the base-side and tip-side portions; a water supply pipe for supplying cooling fluid to the cooling cavity is in the form of a straight pipe extending from the base end to the tip-side within the base-side tubular portion of the cooling jacket along the gas pipe; the water supply pipe opens toward the inner circumferential surface of the tip-side tubular portion at the tip portion of the base-side tubular portion, so that the cooling fluid supplied through the water supply pipe is discharged toward the inner circumferential surface of the tip-side tubular portion; and a drainage pipe for draining the cooling fluid from the cooling cavity is provided in the base-side tubular portion .

With a tube heating burner constructed according to this embodiment, the nozzle tip has nozzles that open toward the outer periphery at multiple locations around the circumference. This allows multiple flames to form from the nozzles toward the outer periphery, allowing a tube, such as a water tube used in a boiler, to be heated simultaneously from its inner periphery at multiple locations around the circumference. Therefore, when it is necessary to heat a tube at multiple locations around the circumference or over a wide area, the time required to heat the tube can be significantly reduced compared to heating with a burner of conventional construction.

In addition, with conventional burners that produce only one flame at the tip, in order to heat the tube at multiple locations around the circumference or over a wide area, it was necessary to rotate the burner and change the position where the flame hits the tube around the circumference. However, with this version, multiple nozzles are spaced apart around the circumference, making it easier or even unnecessary to rotate the burner, making heating easier.

Heating tubes with a burner does not require large-scale equipment like high-frequency induction heating, and does not require complex control depending on the object being heated, so it can be done simply and at low cost.

Because the flame is formed in the direction toward the outer periphery, when inserting the tip nozzle of the burner into the tube, there is no need to tilt the center axis of the tip nozzle with respect to the axial direction of the tube, and it is sufficient to insert the tip nozzle so that the center axis of the tip nozzle and the axial direction of the tube are approximately parallel. Therefore, the tip nozzle can be inserted into a relatively thin tube, and it can also be inserted further into the tube.
Furthermore, by cooling the gas line with the cooling fluid in the cooling cavity, flashback to the gas line through which the premixed combustion gases are conducted is prevented.
In addition, since the cooling cavity is provided so as to extend not only to the tip end portion but also to the base end portion, the combustion gas is sufficiently cooled up to the tip nozzle portion, and flashback is more effectively prevented.

In the second aspect, in the tube heating burner described in the first aspect, the multiple nozzle holes are located at multiple locations spaced apart from one another in the circumferential direction of the tip nozzle portion, and the multiple nozzle holes are evenly spaced in the circumferential direction of the tip nozzle portion at four or more locations.

With a tube heating burner constructed according to this embodiment, flames directed toward the outer periphery are formed at four or more locations around the circumference, making it possible to simultaneously heat a wide area around the circumference of the tube without rotating the burner significantly. Depending on the number of nozzles formed, the nozzle diameter (shape and size of the flame formed), and the diameter of the tube, it may even be possible to simultaneously heat the entire circumference of the tube by simply holding the burner in the orientation at the time of insertion without rotating it.

A third aspect is a tube heating burner according to the first or second aspect, in which the nozzle holes are located at multiple locations spaced apart from each other in the axial direction of the tip nozzle portion, and at multiple locations in the circumferential direction.

With a tube heating burner constructed according to this embodiment, the flames formed at the nozzles located at multiple axial positions on the tip nozzle section allow the tube to be heated simultaneously over a wider axial range. Therefore, even if the portion of the tube to be heated is long in the axial direction, the portion can be heated in a short time without having to move the burner significantly in the axial direction.

A fourth aspect is a tube-heating burner according to the third aspect, wherein the plurality of nozzle holes provided on adjacent circumferential lines in the axial direction of the tip nozzle portion are located at multiple locations spaced apart from one another on the circumferential lines, and the nozzle holes located on each circumferential line are offset from one another in the circumferential direction so that they do not overlap when projected in the axial direction.

A tube heating burner constructed in accordance with this embodiment can simultaneously heat the tube at multiple locations in different axial and circumferential directions, making it possible to simultaneously heat a wider area of the tube.

A fifth aspect is a tube heating burner according to any one of the first to fourth aspects, in which the nozzle opening is open in the radial direction of the tip nozzle portion.

With a tube heating burner constructed according to this aspect, the flame formed at the nozzle extends radially, making it easier to blow the flame onto a predetermined position on the inner surface of the tube, thereby efficiently heating the tube.

A sixth aspect is a tube-heating burner according to any one of the first to fifth aspects, wherein the opening area of the nozzle is 1/5 or less of the cross-sectional area of the flow path of the combustion gas inside the tip nozzle portion.

With a tube heating burner constructed according to this aspect, the opening area of the nozzle is made sufficiently small relative to the cross-sectional area of the combustion gas flow path. Therefore, even if multiple nozzles are connected to the combustion gas flow path at the tip nozzle, the necessary combustion gas can be supplied to each nozzle at a sufficiently high pressure, allowing an appropriate flame to be obtained.

In a seventh aspect, in the tube heating burner described in any one of the first to sixth aspects, a block-shaped tip nozzle portion having a thicker peripheral wall than the gas pipeline is provided at the tip of the gas pipeline, and the cooling cavity into which the cooling fluid is guided is formed so as to surround the gas pipeline at least in the tip portion of the gas pipeline, and the wall portion on the tip side of the cooling cavity is constituted by the tip nozzle portion, so that the cooling cavity reaches the tip nozzle portion.

With a tube heating burner constructed according to this aspect, the gas pipeline is cooled by the cooling fluid in the cooling cavity, preventing flashback in the gas pipeline through which the premixed combustion gas is guided. In particular, because the cooling cavity extends to the tip nozzle, the tip nozzle is cooled, preventing flashback of the combustion gas into the tip nozzle.

In an eighth aspect, in the tube heating burner described in the seventh aspect , the tip end portion of the gas pipeline including the tip nozzle portion extends at an incline relative to the base end portion of the gas pipeline which extends linearly and constitutes a joint portion to be gripped by an operator.

With a tube heating burner constructed according to this aspect, the base end portion of the gas pipe that forms the joint gripped by the operator is inclined relative to the tip end portion of the gas pipe that includes the tip nozzle, making it easier for the operator to handle the tube heating burner when performing heating work in a narrow work space.

The ninth aspect is a tube heating burner as described in the eighth aspect, in which the cooling fluid pipe through which the cooling fluid flows is housed together with the gas pipe in a joint housing, forming a joint portion that is gripped by an operator.

In a tube heating burner constructed according to this embodiment, if the joint portion is composed of a gas pipe and a cooling fluid pipe that extend independently, the operator must grasp multiple pipes, making it difficult to grip and perform the work. Therefore, by integrating the gas pipe and the cooling fluid pipe into a joint housing, the operator can more easily grasp the joint portion (joint housing), improving workability.

According to the present invention, the tube can be heated easily and quickly using a flame. For example, when removing the tube from a boiler drum using thermal shrinkage, the portion of the tube that is inserted and fixed to the drum can be heated easily and quickly.

FIG. 1 is an overall view showing a tube-heating burner according to a first embodiment of the present invention; FIG. 2 is an enlarged view of part II in FIG. 1 . III-III cross-sectional view of FIG. Photo showing the internal structure of a water tube boiler drum FIG. 2 is a diagram illustrating the use state (heating process) of the tube-heating burner shown in FIG. 1. VI-VI cross-sectional view of FIG. Photo showing the cooling process of the water tubes FIG. 1 is an overall view showing a tube-heating burner according to a second embodiment of the present invention; IX-IX cross-sectional view of FIG. A photograph showing the entire prototype of the tube heating burner according to the present invention. A photograph showing the tip of the prototype of the tube heating burner shown in Figure 10 FIG. 10 is a cross-sectional perspective view showing a tip nozzle portion of a tube-heating burner according to another embodiment of the present invention. A photograph showing a conventional method for removing a tube, in which an external force is applied to the open end of the tube to deform it and remove the tube from the mounting hole of the drum. Photo showing a conventional burner

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows a tube heating burner (hereinafter referred to as "burner") 10 as a first embodiment of the present invention. The burner 10 has a longitudinal burner body 14 equipped with a gas pipe 12. The burner body 14 is formed entirely from a metal material.

The burner body 14 has a base end that is composed of a fuel port 16 and an oxygen port 18. The fuel port 16 is generally cylindrical and is connected to a fuel cylinder (not shown) for supplying fuel gas. The fuel supplied from the fuel cylinder to the fuel port 16 may be, for example, acetylene gas, hydrogen gas, or liquefied petroleum gas. The oxygen port 18 has roughly the same cylindrical shape as the fuel port 16 and is connected to an oxygen cylinder (not shown) for supplying oxygen. The oxygen port 18 does not necessarily need to be supplied with only oxygen; for example, it may be supplied with air, a gas mixture containing oxygen. Both the fuel port 16 and the oxygen port 18 constitute the base end of the gas pipeline 12, and the base end opening of the gas pipeline 12 is composed of two openings: the base end opening of the fuel port 16 and the base end opening of the oxygen port 18.

The fuel port 16 and oxygen port 18 are connected to a Y-shaped member 20 that branches into two at its base end. The Y-shaped member 20 has an inner bore with two base-end openings and one tip-end opening, and one of the fuel port 16 and one of the oxygen ports 18 are fixed to the base-end opening by means of screws or other means. As a result, the gas pipe 12, which branches into two at the base end, merges at the tip of the Y-shaped member 20. The Y-shaped member 20 is equipped with a screw-type valve that adjusts the flow rate of the inner bore that communicates with the oxygen port 18, and the amount of oxygen supplied can be adjusted by rotating the first handle 22.

An internal conduit 24, which constitutes the base-end portion of the gas conduit 12, is attached to the tip opening of the Y-shaped member 20. The internal conduit 24 is composed of a linearly extending cylindrical pipe, and its base end is inserted into the tip opening of the Y-shaped member 20. The outer periphery of the internal conduit 24 is surrounded by a joint housing 26. The joint housing 26 is approximately cylindrical and is provided in an externally inserted state at a position spaced apart from the outer periphery of the internal conduit 24. Its base-end opening is fixed in an externally inserted state to the tip of the Y-shaped member 20. In this embodiment, the joint housing 26 is constructed by screwing together two approximately semi-cylindrical parts, but it can also be constructed from a single approximately cylindrical part. When heating the tube with the burner 10, the operator grasps the joint housing 26 to perform the heating operation. Therefore, the joint housing 26 serves as the joint portion of the burner 10, and the internal pipe 24 located on the inner periphery of the joint housing 26 serves as the portion that constitutes the joint portion of the gas pipe 12.

A flow control member 28 is attached to the distal end of the internal conduit 24. The flow control member 28 includes a control unit main body 30 that extends generally parallel to the internal conduit 24. The control unit main body 30 is generally cylindrical, and a flow control valve 32 is inserted into its inner bore. The flow control valve 32 has a conical surface at its distal end that decreases in diameter toward the distal end. It is attached to the distal end of a slide shaft 34 that is threadedly attached to the proximal opening of the control unit main body 30, allowing it to move toward both the distal and proximal ends. As the slide shaft 34 rotates and moves toward the distal end, the flow control valve 32 approaches the distal-side facing surface of the inner bore of the control unit main body 30, thereby decreasing the flow rate through the inner bore of the control unit main body 30. On the other hand, as the slide shaft 34 rotates and moves toward the proximal end, the flow control valve 32 moves away from the distal-side facing surface of the inner bore of the control unit main body 30, thereby increasing the flow rate through the inner bore of the control unit main body 30. The base end of the slide shaft 34 protrudes further proximally than the flow rate adjustment member 28, and a second handle 36 is provided on this protruding portion, making it easier for the operator to operate the flow rate adjustment valve 32.

The flow rate adjustment member 28 has a side connection portion 38 that extends laterally from the adjustment portion main body 30. The side connection portion 38 is provided integrally with the adjustment portion main body 30, and the end of the side connection portion 38 is fixed in an externally inserted state to the internal conduit 24 and fixed in an internally inserted state to the coupling housing 26. The inner bore of the side connection portion 38 communicates with the inner bore of the internal conduit 24 and the inner bore of the adjustment portion main body 30.

An intermediate pipe 40 is provided at the tip of the flow rate adjustment member 28. The intermediate pipe 40 is generally cylindrical. The length of the intermediate pipe 40 can be adjusted as needed to adjust the length of the burner body 14.

A tip conduit 42, which constitutes the tip portion of the gas conduit 12, is provided at the tip end of the intermediate conduit 40. The tip conduit 42 is a pipe-shaped member with approximately constant inner and outer diameters. The tip conduit 42 has a base straight section 44 and a tip straight section 46 that each extend linearly, with a curved section 48 provided between the base straight section 44 and the tip straight section 46. The curved section 48 is provided in the middle of the length of the tip conduit 42 and curves toward the tip in the same direction as the lateral connection section 38 of the flow rate adjustment member 28. Because the curved section 48 is provided midway through the tip conduit 42, the base straight section 44 and the tip straight section 46, which are provided on either side of the curved section 48, are inclined relative to each other. Although the burner body 14 has a stepped shape at the side connection portion 38 proximal to the curved portion 48, the overall shape is longitudinal and extends linearly in the left-right direction in FIG. 1, with the portion of the burner body 14 distal to the curved portion 48, including the tip nozzle portion 52, extending linearly and at a relative incline to the portion of the burner body 14 proximal to the curved portion 48, including the joint portion (joint housing 26).

A connecting member 50 is attached to the tip of the tip conduit 42. The connecting member 50 is cylindrical, with its base end secured to the tip straight section 46 of the tip conduit 42 in an externally inserted state, and its tip end secured to the tip nozzle section 52 in an internally inserted state. The method for securing the connecting member 50 to the tip conduit 42 and tip nozzle section 52 is not particularly limited, but it can be secured by means of a screw structure, press fitting (fitting), welding, or the like.

The tip nozzle section 52 constitutes the tip portion of the burner body 14. It is a roughly cylindrical block and is made of heat-resistant steel (including iron-based heat-resistant alloys) or heat-resistant alloys such as cobalt-based, nickel-based, or chromium-based alloys. As shown in Figures 2 and 3, the tip nozzle section 52 has a circular internal cavity 54 extending along its central axis and opening at its base end. The internal cavity 54 is connected to the inner bore of the tip pipe 42 via the inner bore of the connecting member 50, forming the tip of the gas pipe 12. Therefore, the gas pipe 12 continues from the base end openings of the fuel port 16 and oxygen port 18 to the internal cavity 54 of the tip nozzle section 52. The internal cavity 54 does not open at the tip end surface of the tip nozzle section 52; instead, it is concave and opens toward the base end, not toward the tip end. The thickness of the peripheral wall of the internal cavity 54 in the tip nozzle portion 52 is greater than the maximum thickness of the peripheral wall of the gas pipeline 12 other than the tip nozzle portion 52.

The tip nozzle section 52 has multiple ejection ports 56 that communicate with the internal cavity 54. The ejection ports 56 are circular holes with a smaller diameter than the internal cavity 54. As shown in Figures 2 and 3, the ejection ports 56 penetrate the peripheral wall of the internal cavity 54 and do not open in the axial direction of the tip nozzle section 52, but rather open outward on the outer circumferential surface of the tip nozzle section 52. In particular, in this embodiment, the tip nozzle section 52 does not have any ejection ports that open on the central axis L1, nor any ejection ports that open on the most distal end surface of the tip nozzle section 52, and no ejection ports with opening ends parallel to the central axis L1.

That is, the central axis L2 of the ejection port 56 extends in a radial direction substantially perpendicular to the central axis L1 of the tip nozzle section 52, and the opening direction of the ejection port 56 is the radial direction of the tip nozzle section 52. The ejection ports 56 are located at multiple locations circumferentially on the outer peripheral surface of the tip nozzle section 52. In this embodiment, the ejection ports 56 are located at multiple locations spaced apart from each other circumferentially of the tip nozzle section 52 and are arranged substantially evenly circumferentially. The opening area of the ejection port 56 is preferably no more than 1/5, and more preferably no more than 1/10, of the cross-sectional area of the flow path of the combustion gas inside the tip nozzle section 52 (cross-sectional area of the internal space 54).

2, at two locations spaced apart in the axial direction of the tip nozzle section 52 (on two circumferential lines spaced apart a predetermined distance in the axial direction), a plurality of tip-side ejection ports 56a and a plurality of base-side ejection ports 56b are provided, each located on a respective circumferential line. In this embodiment, on the tip-side circumferential line, the ejection ports 56a are located at four locations spaced apart in the circumferential direction of the tip nozzle section 52, and on the base-side circumferential line, the ejection ports 56b are located at four locations spaced apart in the circumferential direction of the tip nozzle section 52. The four ejection ports 56a are arranged approximately evenly in the circumferential direction of the tip nozzle section 52, and the four ejection ports 56b are also arranged approximately evenly in the circumferential direction of the tip nozzle section 52. The eight nozzles 56 are arranged at different phases in the circumferential direction. In this embodiment, the four nozzles 56a and the four nozzles 56b are circumferentially out of phase with each other by 45 degrees. This allows the eight nozzles 56 to be arranged at different positions in the circumferential direction and to be approximately evenly spaced in the circumferential direction, with the eight nozzles 56 spaced every 45 degrees. In other words, the nozzles 56a on the circumferential line at the tip end and the nozzles 56b on the circumferential line at the base end are arranged at offset positions in the circumferential direction so as not to overlap each other when projected in the direction of the central axis. The eight nozzles 56 may have different diameters or cross-sectional shapes, but it is desirable for them to be identical to each other in order to obtain a consistent flame 70 (described below).

A cooling jacket 58 is attached to the burner body 14. The cooling jacket 58 is generally cylindrical and is fitted over the distal conduit 42 at a distance from the distal conduit 42. The base end opening is liquid-tightly sealed by a sealing member 60, and the tip opening is fixed over the distal conduit 42 and liquid-tightly sealed by the distal nozzle 52. This forms a cooling cavity 62 within the cooling jacket 58, surrounding the distal conduit 42. The cooling cavity 62 is fluid-tightly sealed from the external space and is located between the distal conduit 42 and the cooling jacket 58. The cooling cavity 62 extends over both the distal end portion (tip straight portion 46) and the proximal end portion (proximal straight portion 44) of the distal conduit 42 relative to the curved portion 48. The cooling cavity 62 surrounds the peripheries of the proximal straight portion 44, the curved portion 48, and the distal straight portion 46. The base end of the cooling cavity 62 does not reach the base end of the tip conduit 42, and the base end straight section 44 of the tip conduit 42 extends further toward the base end than the cooling cavity 62. The tip of the cooling cavity 62 reaches the tip nozzle section 52, and the wall surface on the tip side of the cooling cavity 62 is formed by the tip nozzle section 52.

A water supply line 64 is connected to the cooling cavity 62. The tip of the water supply line 64 is inserted into the cooling cavity 62 and is open, while the base is connected to a water supply system or water tank (not shown) to introduce water as a cooling fluid into the cooling cavity 62. The water flowing through the cooling cavity 62 cools the combustion gas flowing through the gas line 12, preventing backfire, which is the ignition of the combustion gas in the gas line 12. In this embodiment, the water supply line 64 is equipped with a valve for adjusting the flow rate, and the flow rate of water supplied to the cooling cavity 62 can be adjusted by rotating a third handle 66 connected to the valve. Note that the cooling fluid is not limited to water; it may be a liquid other than water or a gas such as air.

A drainage pipe 68 is connected to the cooling cavity 62. In this embodiment, the drainage pipe 68 penetrates a portion of the cooling jacket 58 and protrudes toward the outer periphery. The drainage pipe 68 is always open, and water in the cooling cavity 62 is discharged to the outside through the drainage pipe 68. The water discharged from the cooling cavity 62 may be discarded, or, for example, it may be guided to the water supply pipe 64 after cooling and circulated.

In the burner 10 constructed as described above, fuel and oxygen are supplied from the base end opening of the gas pipe 12 and premixed within the gas pipe 12 to form combustion gas, which is then ejected from the nozzle 56 of the tip nozzle portion 52. When the ejected combustion gas is ignited, a flame 70 is formed at the nozzle 56, as shown by the dashed-dotted line in Figures 2 and 3. For ease of understanding, in the following description, the flame formed at the nozzle 56a may be referred to as flame 70a, and the flame formed at the nozzle 56b may be referred to as flame 70b.

The flames 70 are formed toward the outer periphery, which is the opening direction of the nozzle 56. In this embodiment, the flames are formed toward the outer periphery in a radial direction approximately perpendicular to the central axis L1 of the tip nozzle portion 52, with eight flames 70 formed radially and approximately evenly distributed in the circumferential direction. The size and combustion efficiency of the flames 70 can be controlled by operating the first handle 22, which adjusts the amount of oxygen supplied, and the second handle 36, which adjusts the amount of combustion gas supplied, to adjust the ratio of fuel to oxygen in the combustion gas or the amount of combustion gas supplied to the tip nozzle portion 52.

The burner 10 is used, for example, in the tube removal process for removing water tubes 76 from a drum 74, which serves as a support wall member, of a water tube boiler 72 as shown in Figure 4. As is commonly known, a water tube boiler 72 has a structure in which a steam drum and a water drum are connected by a large number of water tubes 76. Water flowing through the water tubes 76 between the steam drum and the water drum is heated within the water tubes 76, thereby extracting steam from the steam drum. The drum 74 may be either a steam drum or a water drum.

In the water tube boiler 72, the open ends of the water pipes 76 are inserted into the mounting holes 78 of the drum 74, and the inserted portions are expanded to fit and securely fit against the inner surfaces of the mounting holes 78. The open ends of the water pipes 76 also protrude from the mounting holes 78, and the expanded diameter of these protruding portions prevents the water pipes 76 from slipping out of the mounting holes 78. The expanded diameter of these protruding portions forms tapered expanded portions 80, preventing the water pipes 76 from slipping out of the mounting holes 78 (see Figure 5). However, the drum 74 and the water pipes 76 are not fixed together in a partially integrated manner, as by welding, but are mechanically fixed together by fitting them together while maintaining their independent state as separate members. Both the drum 74 and the water pipes 76 are made of a metal material, such as iron, and the water pipes 76 are subject to deformation, such as expansion due to external forces and contraction due to thermal contraction.

In the method for removing the water pipe 76 inserted and fixed through the mounting hole 78 of the drum 74, the operator first performs a cutting step in which the expanded portion 80 is cut off. The method for cutting off the expanded portion 80 is not particularly limited, but it can be cut off, for example, using a cutting burner. In Figure 5, the cut expanded portion 80 is shown imaginarily by a two-dot chain line.

Next, as shown in Figures 5 and 6, the operator inserts the tip nozzle portion 52 of the burner 10, with the flame 70 formed, into the open end of the water pipe 76 from which the expanded portion 80 has been removed, and sprays the flame 70 onto the open end portion where the water pipe 76 is inserted and fixed into the mounting hole 78, thereby simultaneously heating the open end portion of the water pipe 76 at multiple locations around the circumference. Because the burner 10 generates the flame 70 toward the outer periphery, the operator can spray the flame 70 onto the inner circumferential surface of the open end of the water pipe 76 by inserting the tip nozzle portion 52 into the open end of the water pipe 76 with the center axis L1 of the tip nozzle portion 52 approximately parallel to the axis of the water pipe 76. The heating temperature of the open end of the water pipe 76 by the burner 10 is not particularly limited, but it is preferably 1000°C or higher to effectively induce diameter-reducing deformation due to thermal contraction, as described below.

The burner 10 forms a radial flame 70 directed outward from multiple locations around the tip nozzle portion 52, allowing the flame 70 to be sprayed simultaneously at multiple locations around the water tube 76. This allows the water tube 76 to be heated simultaneously over a wide circumferential range, and the heating process for heating the entire circumference of the open end of the water tube 76 can be completed in a short period of time. In particular, in this embodiment, the flame 70 is formed at four locations around the circumference at the same axial position, allowing the water tube 76 to be heated simultaneously over a wide circumferential range, allowing for efficient heating of the entire circumference.

The burner 10 forms flames 70a and 70b at two axial locations on the tip nozzle portion 52. This means that even if the drum 74 is thick and the mounting hole 78 is long, as shown in Figure 5, it is possible to simultaneously heat a wide axial range of the portion of the water pipe 76 that is inserted and fixed into the mounting hole 78. Furthermore, because flames 70a and 70b are positioned offset from each other in the circumferential direction and open in different directions, even if flames 70a and 70b are formed relatively close to each other in the axial direction, they are unlikely to interfere with each other and become unidirectional flames, and it is possible to simultaneously heat a wide axial and circumferential range.

The opening area of each nozzle 56 is sufficiently small, less than one-fifth the flow path cross-sectional area, which is the cross-sectional area of the internal cavity 54. Therefore, even if multiple nozzles 56 are connected to a single gas pipe 12, combustion gas is stably supplied to each nozzle 56 at the required pressure. This allows a stable flame 70 to be obtained at each nozzle 56, enabling efficient simultaneous heating of multiple locations on the water pipe 76.

The tip of the burner 10 is inserted into the open end of the water pipe 76 with the central axis L1 of the tip nozzle portion 52 parallel to the pipe axis of the water pipe 76. This allows the tip nozzle portion 52 to be inserted as far as necessary, even if the mounting hole 78 is long and the area of the water pipe 76 to be heated is wide in the pipe axis direction. In particular, because there is no need to insert the burner 10 at an angle, the insertion depth of the tip nozzle portion 52 into the water pipe 76 is less likely to be limited by interference between the burner 10 and the water pipe 76, even if the inner diameter of the water pipe 76 is small. This also makes it possible to use a combination of a thinner water pipe 76 and a thicker drum 74.

The tip of the burner 10 inserted into the water pipe 76 is heated by radiant heat from the flame 70 sprayed onto the inner surface of the water pipe 76. However, because it is continuously cooled by the water circulating within the cooling cavity 62, flashbacks that could ignite the combustion gas within the gas pipe 12 are prevented, even during continuous use. In particular, the cooling cavity 62 is provided over a wide area along the length of the gas pipe 12, from the distal end to the proximal end relative to the curved portion 48, providing excellent cooling performance. Furthermore, the cooling cavity 62 is provided so as to reach the tip nozzle 52, and the distal wall of the cooling cavity 62 is formed by the tip nozzle 52. This efficiently cools the tip nozzle 52, effectively preventing flashbacks in the internal cavity 54 of the tip nozzle 52.

In particular, in this embodiment, the cooling water outlet from the water supply line 64 opens toward the tip of the cooling cavity 62, at a position a predetermined distance forward from the rear end of the cooling cavity 62 (e.g., a position closer to the tip than the longitudinal midpoint). Furthermore, in this embodiment, the drain line 68 opens toward the base end of the cooling cavity 62 (e.g., a position closer to the base end than the outlet of the water supply line 64). This creates a flow pattern within the cooling cavity 62 in which the cooling water discharged from the water supply line 64 preferentially flows toward the tip nozzle portion 52 within the cooling cavity 62, and then flows rearward and is discharged through the drain line 68. As a result, the cooling of the tip nozzle portion 52 by the cooling water can be more efficiently and stably achieved.

In addition, since the outer surface of the open end of the water tube 76 is constrained by the inner surface of the mounting hole 78 in the drum 74 during heating, the water tube is heated in a state where any increase in its outer diameter due to thermal expansion is limited or prevented.

After completing the process of heating the water pipe 76, the operator removes the burner 10 from the water pipe 76 and inserts a cooling device 82 into the water pipe 76, as shown in FIG. 7. The cooling device 82 cools the open end of the heated water pipe 76 by spraying a cooling fluid, such as air or water, from the tip at a predetermined pressure. In this embodiment, the cooling device 82 sprays air to air-cool the water pipe 76. The open end of the heated water pipe 76 is rapidly cooled, causing thermal contraction that slightly reduces its outer diameter, thereby reducing or eliminating the force holding the water pipe 76 in the mounting hole 78 of the drum 74. The water pipe 76 is then removed from the mounting hole 78, completing the removal of the water pipe 76 from the drum 74. The method for removing the water pipes 76 from the drum 74 after cooling is not particularly limited; for example, the water pipes 76 may be removed by pulling them outward or inward from the drum 74, or by pushing them inward or outward from the drum 74.

This method of removing the water pipe 76, which utilizes the thermal contraction of the water pipe 76, is less likely to cause significant damage to the drum 74 than conventional removal methods that deform the open end of the water pipe 76 by applying a large load (external force) such as a pressing force. In particular, dents and scratches on the drum 74 are avoided on the inner surface of the mounting hole 78, which connects the water pipe 76 to the drum 74, and around the opening edge. This avoids problems such as gaps between the replaced water pipe 76 and the drum 74 due to damage to the drum 74.

Furthermore, because heating is performed by the flame 70 of the burner 10, no large-scale equipment such as high-frequency induction heating is required, and the water tubes 76 can be removed from the drum 74 easily and inexpensively. Therefore, the above-described tube removal method is easily applicable to removing tubes from small-scale boilers, for example, where it is difficult to use high-frequency induction heating for tube removal.

Furthermore, by using the burner 10 to simultaneously heat the open end of the water pipe 76 at multiple locations around the circumference, the time required for the heating process can be significantly reduced, allowing the removal work to be completed in a short time. This reduces the burden on the operator working to remove the water pipe 76 inside the narrow drum 74, and prevents the work environment from becoming worse due to radiant heat, etc.

Figure 8 shows a tube heating burner 90 as a second embodiment of the present invention. The burner 90 is equipped with a tip nozzle portion 92. In the following description, components and parts that are substantially the same as those in the first embodiment will be denoted by the same reference numerals in the figure and will not be described again.

The tip nozzle section 92 has eight nozzles 56a at the tip end and eight nozzles 56b at the base end. The nozzles 56a and 56b are arranged in the same phase circumferentially, and nozzles 56a and 56b arranged at corresponding positions circumferentially are aligned linearly in the axial direction. As shown in Figure 9, the nozzles 56b are evenly spaced circumferentially, with adjacent nozzles 56b, 56b extending in different radial directions at a relative inclination angle of 45 degrees. The circumferential arrangement of the eight nozzles 56a is the same as the circumferential arrangement of the eight nozzles 56b shown in Figure 9.

The burner 90 constructed in accordance with this embodiment has a greater number of nozzles 56 than the burner 10 of the first embodiment, further improving the heating efficiency of the tube. Furthermore, by narrowing the spacing between the flames 70 in the circumferential direction of the tip nozzle portion 92, it is possible to further reduce the need to rotate the burner 90 when heating the entire open end of the tube.

The burner 90 has a water supply line 94 that supplies cooling fluid to the cooling cavity 62 and extends along the burner body 14 to the base end of the burner body 14. In addition, a drain line 96 that discharges cooling fluid from the cooling cavity 62 also extends along the burner body 14 to the base end of the burner body 14. As a result, the routing of the water supply line 94, drain line 96, and the tubing (not shown) connected to these lines 94 and 96 is unlikely to affect the operability of the burner 90, and these lines 94, 96 and tubing are unlikely to get in the way of the operator. Furthermore, the attachment and detachment parts are located close to the operator, making the work easier when attaching or detaching a water supply device to the water supply line 94 or a drain device to the drain line 96.

When the water supply line 94 and the drain line 96 serving as cooling fluid lines extend along the burner body 14 to the base end in this manner, a portion of the water supply line 94 and a portion of the drain line 96 may be housed in the joint housing 26. This allows the water supply line 94 and the drain line 96 to be easily gripped by the operator when gripping the joint housing 26, and the outer periphery of the burner 90 can be made to be easy to grip. Note that a holding mechanism such as a hook that holds the water supply line 94 and the drain line 96 in a position that does not get in the way may be provided in the burner body 14 instead of, or in addition to, housing the lines 94, 96 in the joint housing 26.

The inventors fabricated a prototype tube heating burner with a structure according to the present invention, as shown in Figures 10 and 11, and conducted tube heating experiments. The results showed that the heating process, which required approximately 1 minute and 30 seconds when using a conventional burner with a single flame at the tip, was completed in approximately 30 seconds when using the tube heating burner according to the present invention. These experimental results confirm that the tube heating burner according to the present invention significantly reduces the time required for the tube heating process compared to when using a burner with a conventional structure. Furthermore, the prototype tube heating burner according to the present invention was able to heat the entire circumference of the tube without changing the direction of the flame blowing toward the tube by rotating it, making the heating process easier than with a burner with a conventional structure. The prototype tube heating burner according to the present invention, shown in Figures 10 and 11, has a similar structure to the tube heating burner 90 shown in the second embodiment, and therefore, reference numerals corresponding to those of the second embodiment are used in Figures 10 and 11 to facilitate understanding of the structure.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific descriptions. For example, the number, size, and arrangement of the ejection ports 56 formed in the tip nozzle portion 52 are not limited. Furthermore, it is desirable that the multiple ejection ports 56 be arranged approximately evenly around the circumference of the tip nozzle portion 52, but for example, the arrangement of the ejection ports 56 in the circumferential direction may be uneven.

The nozzle 56 preferably opens radially, perpendicular to the central axis L1 of the tip nozzle portion 52. However, it is sufficient if the nozzle 56 opens on the outer peripheral surface of the tip nozzle portion 52 in a direction intersecting the central axis L1. The opening direction of the nozzle 56 is understood to be the direction of the central axis at the tip of the nozzle 56 opening to the outside. Specifically, for example, the nozzle 56 may be inclined from the inner periphery of the tip nozzle portion 52 toward the outer periphery toward the tip. This is expected to make it more difficult for flames to blow out from the tube opening toward the operator when the tube is heated. However, the inclination angle of the central axis L2 of the nozzle 56 relative to the central axis L1 of the tip nozzle portion 52 is preferably 45 degrees or more and 135 degrees or less, and more preferably 60 degrees or more and 120 degrees or less. The opening direction of the nozzle 56 may also be inclined circumferentially. The nozzle 56 is not necessarily limited to a linear shape and may, for example, be curved or bent.

The multiple nozzles 56 provided at multiple circumferential locations may be arranged, for example, on a single annular outer periphery (circumferential line) of the tip nozzle section 52, or may be arranged at positions offset from one another along the length (central axis) of the tip nozzle section 52. For example, the multiple nozzles 56 may be arranged so that they are scattered at different circumferential positions in an outer periphery surface region (cylindrical or band-shaped region) extending over a predetermined area along the length of the tip nozzle section 52. More specifically, for example, the multiple nozzles 56 may be arranged along one or more spiral lines extending around the outer periphery of the tip nozzle section 52, or the multiple nozzles 56 may be arranged in a staggered pattern along a line extending in a sine wave shape or the like along the circumferential direction. Alternatively, as described above, the multiple nozzles 56 may be arranged on each of the annular outer peripheries (circumferential lines) spaced apart from one another along the length of the tip nozzle section 52.

By shaping the nozzles to extend a predetermined length in the circumferential direction, they can be positioned at multiple locations around the outer circumferential surface of the tip nozzle section 52. In other words, there are no restrictions on the number of nozzles arranged in the axial direction, the number arranged in the circumferential direction, or the shape of the opening, and they are not limited to a structure in which multiple independent nozzles are arranged spaced apart around the circumferential direction of the tip nozzle section 52. It is also possible to position adjacent nozzles in the circumferential direction so close together that the separation between them is essentially zero. For example, as in the tip nozzle section 100 shown in Figure 12, adjacent nozzles in the circumferential direction are positioned close to each other and are continuous, so that the nozzles 102 are arranged continuously around the entire outer circumferential surface of the tip nozzle section 100.

In the second aspect of the present invention, the multiple nozzle holes 56 evenly spaced around the periphery of the tip nozzle portion 52 are not to be interpreted as being strictly evenly spaced mathematically, but rather as being within a range within which the effects of this aspect can be achieved. For example, mechanical processing errors are naturally allowed, and if there are locations where it is difficult to form nozzle holes 56 due to processing or structural reasons, this aspect can also be implemented by shifting the positions of some of the nozzle holes 56 or eliminating the nozzle holes 56 at those locations. The first aspect of the present invention also includes an aspect in which multiple nozzles 56 are provided at uneven intervals in the circumferential direction, and even if the flame is biased in the circumferential direction, by rotating the burner slightly in the circumferential direction (in a circumferential region of less than one circumference, preferably in a circumferential region of less than half the circumference, and more preferably in a circumferential region of less than one-third of the circumference) around the central axis while the flame is being ejected, it is possible to heat the tube approximately evenly in the circumferential direction from the inner circumferential surface side much more quickly and easily than with a single-flame burner of conventional construction.

The tip end portion of the burner body 14 does not necessarily have to have a curved portion 48, and the tip end portion of the burner body 14 does not necessarily have to be inclined relative to the base end portion. Furthermore, the relative inclination angle between the tip end portion and the base end portion of the burner body 14 is set appropriately taking into consideration factors such as ease of heating, and is not particularly limited.

The components of the gas pipeline 12 are merely examples, and the component configuration is not particularly limited as long as they constitute the gas pipeline 12 all the way to the tip nozzle portion 52. For example, the gas pipeline 12 may be composed of a single component. Furthermore, for example, an exhaust mechanism for discharging combustion gas from the gas pipeline 12 after use may be provided midway along the gas pipeline 12.

It is desirable for the cooling cavity 62 to be provided on both the tip and base ends of the curved portion 48 of the gas pipe 12, but it may also be provided only at the tip of the burner 10, for example, on the outer periphery of the tip straight portion 46 but not on the outer periphery of the base straight portion 44.

When inserting the tip nozzle portion 52 into the water pipe 76 for heating, a positioning portion may be provided to radially position the tip nozzle portion 52 relative to the water pipe 76, making it easier to maintain the tip nozzle portion 52 spaced apart from the inner surface of the water pipe 76 over the entire circumference. The positioning portion may, for example, be provided so as to protrude outward from the portion of the burner body 14 inserted into the water pipe 76 and abut against the inner surface of the water pipe 76, thereby radially positioning and holding the tip nozzle portion 52 and the water pipe 76. Alternatively, the positioning portion may, for example, be provided so as to protrude outward from the burner body 14 and be superimposed on the outer surface of the open end of the water pipe 76, thereby radially positioning and holding the tip nozzle portion 52 and the water pipe 76.

A protective structure can be provided to prevent flames from spraying out from the opening of the water pipe 76 toward the operator when the water pipe 76 is heated by the burner 10. One possible protective structure is to provide a circular protective plate that protrudes outward from the tip of the cooling jacket 58. This allows the protective plate to guide the flames spraying out from the water pipe 76 toward the outer periphery, preventing them from spraying out toward the operator. It is also possible to utilize airflow that flows away from the operator.

In the above embodiment, a premix burner was described in which fuel and oxygen are premixed in the gas pipe 12 and the resulting premixed gas is ejected from the nozzle 56 as combustion gas. However, the present invention can also be applied to a diffusion burner in which fuel and oxygen are ejected separately from the nozzle 56 and mixed after ejection. The fuel may be a gaseous fuel gas, or it may be liquid and sprayed as a fine mist to be mixed with oxygen. It is also possible to employ a structure similar to that of a cutting burner, for example, so that the flame intensity can be adjusted over a wide range.

The burner according to the present invention is not necessarily used only when removing water tubes from a water tube boiler, but can be widely applied to cases where a tube body is heated simultaneously at multiple locations in the circumferential direction from the inner circumference. Specifically, for example, the burner according to the present invention can be used when removing a tube body (boiler tube) in boilers other than water tube boilers, and can also be used when heating a ring-shaped tube body that forms an outer ring or a fitting hole when shrink-fitting a rolling bearing.
Furthermore, the present invention originally includes each of the inventions described below in (i) to (xi), and the configurations and effects thereof will be described below.
The present invention provides
(i) A tube heating burner in which the combustion gas outlets in the tip nozzle part of the burner body are not open in the axial direction of the tip nozzle part, but are located at multiple points in the circumferential direction on the outer circumferential surface of the tip nozzle part and are open toward the outer periphery.
(ii) A tube-heating burner according to (i), in which the plurality of nozzles are located at a plurality of positions spaced apart from one another in the circumferential direction of the tip nozzle portion, and the plurality of nozzles are provided at four or more positions in the circumferential direction of the tip nozzle portion, evenly spaced in the circumferential direction of the tip nozzle portion.
(iii) The tube-heating burner according to (i) or (ii), wherein the nozzles are located at a plurality of positions in the circumferential direction, each of which is spaced apart from one another in the axial direction of the tip nozzle portion.
(iv) A tube heating burner according to (iii), wherein the plurality of nozzle holes provided on circumferential lines adjacent to each other in the axial direction of the tip nozzle portion are located at a plurality of positions spaced apart from each other on the circumferential lines, and the nozzle holes located on each circumferential line are shifted from each other in the circumferential direction so as not to overlap each other when projected in the axial direction.
(v) The tube-heating burner according to any one of (i) to (iv), wherein the nozzle is open in the radial direction of the tip nozzle portion.
(vi) A tube-heating burner according to any one of (i) to (v), wherein the opening area of the outlet is 1/5 or less of the cross-sectional area of the flow path of the combustion gas inside the tip nozzle portion.
(vii) A tube heating burner according to any one of (i) to (vi), wherein the burner body is provided with a block-shaped tip nozzle portion having a thicker peripheral wall than the gas pipe at the tip of the gas pipe through which the premixed combustion gas is introduced, a cooling cavity through which a cooling fluid is introduced is formed so as to surround the periphery of the gas pipe at least at the tip portion of the gas pipe, and the wall portion on the tip side of the cooling cavity is constituted by the tip nozzle portion, so that the cooling cavity reaches the tip nozzle portion;
(viii) A tube heating burner according to (vii), wherein a curved portion is provided in the intermediate portion in the longitudinal direction of the gas pipeline, and a tip portion of the gas pipeline including the tip nozzle portion extends at a relative incline with respect to a base portion of the gas pipeline that extends linearly and constitutes a joint portion that is gripped by an operator, and the cooling cavity is formed across both the base portion and the tip portion, including the curved portion.
(ix) A tube heating burner according to (vii) or (viii), in which the cooling fluid pipe through which the cooling fluid flows is accommodated in a joint housing together with the gas pipe to form a joint portion that is held by an operator.
(x) A method for removing a tube, the open end of which is inserted and fixed into a mounting hole of a support wall member in a boiler, from the support wall member, the method including a heating step of simultaneously heating the open end portion of the tube at a plurality of circumferential positions by blowing flames simultaneously at a plurality of circumferential positions against an inner peripheral surface of the open end portion of the tube inserted and fixed into the mounting hole of the support wall member;
(xi) A method for removing a tube in a boiler according to (x), in which the tube heating burner according to any one of (i) to (ix) is used, and in the heating step, the tip nozzle portion of the tube heating burner is inserted into the open end portion of the tube, and flames formed from the plurality of nozzles toward the outer periphery are blown onto the inner periphery of the tube, thereby heating the tube.
This includes inventions relating to:
In the invention described in (i) above, the nozzle nozzle has nozzles at multiple locations around the circumference, which open toward the outer periphery. This allows multiple flames to be generated from the nozzles toward the outer periphery, allowing a tube, such as a water pipe used in a boiler, to be heated simultaneously at multiple locations around the circumference from the inner periphery. Therefore, when multiple locations around the circumference or a wide area of the tube need to be heated, the time required to heat the tube can be significantly reduced compared to heating with a conventional burner. Furthermore, with conventional burners that generate only a single flame at the tip, heating the tube at multiple locations around the circumference or a wide area requires rotating the burner to change the position where the flame strikes the tube around the circumference. However, in this embodiment, the multiple nozzles are spaced apart around the circumference, which simplifies or eliminates burner rotation, facilitating the heating process. Heating a tube with a burner does not require large-scale equipment like high-frequency induction heating, and does not require complex control depending on the heating target, making it simple and inexpensive to implement. Because the flame is formed in the direction toward the outer periphery, when inserting the tip nozzle of the burner into the tube, there is no need to tilt the center axis of the tip nozzle with respect to the axial direction of the tube, and it is sufficient to insert the tip nozzle so that the center axis of the tip nozzle and the axial direction of the tube are approximately parallel. Therefore, the tip nozzle can be inserted into a relatively thin tube, and it can also be inserted further into the tube.
In the invention described in (ii) above, by forming flames directed toward the outer periphery at four or more locations in the circumferential direction, it is possible to simultaneously heat a wide area in the circumferential direction of the tube without rotating the burner. Depending on the number of nozzles formed, the diameter of the nozzles (the shape and size of the flames formed), the diameter of the tube, etc., it may be possible to simultaneously heat the entire circumference of the tube by simply holding the burner in the orientation at the time of insertion without rotating it.
In the invention described in (iii) above, the flames formed at the nozzles provided at multiple locations in the axial direction of the tip nozzle can simultaneously heat a wider range of the tube in the axial direction, so even if the portion of the tube to be heated is long in the axial direction, the portion can be heated in a short time without having to move the burner significantly in the axial direction.
In the invention described in (iv) above, the tube can be heated simultaneously at multiple locations at different axial and circumferential positions, making it possible to heat a wider range of the tube simultaneously.
In the invention described in (v) above, the flame formed at the nozzle extends radially, making it easier to blow the flame onto a predetermined position on the inner surface of the tube, thereby enabling the tube to be heated efficiently.
In the invention described in (vi) above, the opening area of the nozzle is made sufficiently small compared to the cross-sectional area of the flow path of the combustion gas, so that even if multiple nozzles are connected to the flow path of the combustion gas in the tip nozzle portion, the necessary combustion gas is supplied to each nozzle at a sufficiently high pressure, and an appropriate flame can be obtained.
In the invention described in (vii) above, the gas pipeline is cooled by the cooling fluid in the cooling cavity, thereby preventing flashback in the gas pipeline through which the premixed combustion gas is guided. In particular, since the cooling cavity extends to the tip nozzle, the tip nozzle is cooled, preventing flashback of the combustion gas into the tip nozzle.
In the invention described in (viii) above, the base end portion of the gas pipe constituting the joint held by the operator is inclined relative to the tip end portion of the gas pipe conduit including the tip nozzle, making it easier for the operator to handle the tube heating burner when performing heating work in a narrow work space. Since the cooling cavity is provided so as to extend not only to the tip end portion but also to the base end portion, the combustion gas up to the tip nozzle is sufficiently cooled, more effectively preventing flashback.
In the invention described in (ix) above, if the coupling portion is configured with a gas pipeline and a cooling fluid pipeline that extend independently, the operator will have to grip multiple pipelines, which makes it difficult to grip and perform work. Therefore, by integrating the gas pipeline and the cooling fluid pipeline into a coupling housing, the operator can easily grip the coupling portion (coupling housing), improving workability.
In the invention described in (x) above, in a connection structure for a tube having an open end inserted and fixed into a mounting hole in a support wall member such as a drum, the tube is heated while restrained by the support wall member, and then cooled and removed from the mounting hole by thermal contraction, thereby preventing damage to the support wall member during tube removal. In particular, this prevents scratches, such as gouges or dents, from forming around the opening edge of the mounting hole in the support wall member, preventing gaps due to such scratches from forming between the replaced tube and the support wall member, and eliminating the need for repairs to the support wall member. Furthermore, because the heating step during tube removal is performed by flame spraying, there is no need for large-scale equipment or advance preparations such as high-frequency induction heating, and no electrical operation control corresponding to the boiler is required. Therefore, tube removal by thermal contraction, which avoids damage to the boiler, can be performed easily and at low cost. During the heating process, the entire portion of the tube inserted into the mounting hole is heated. However, because the tube is simultaneously heated by the flame at multiple locations around the circumference, the entire circumference of the tube can be heated in a short time. Therefore, for example, by reducing heat transfer from the tube to the drum, the heating efficiency of the tube is improved and adverse effects of heat transfer on the drum are mitigated. Furthermore, for operators, for example, when working inside a narrow drum, the shortened work time reduces the burden on the operator and reduces the problem of a worsening working environment due to radiant heat from the flame. By simultaneously heating the tube at multiple locations around the circumference, the effort required to move the burner to change the direction of the flame around the tube is reduced, simplifying the heating process.
In the invention described in (xi) above, by carrying out the heating process using a tube-heating burner described in any one of aspects (i) to (ix), it is possible to shorten the heating work time and simplify the work.

10. Tube heating burner (first embodiment)
12 Gas conduit 14 Burner body 16 Fuel port 18 Oxygen port 20 Y-shaped member 22 First handle 24 Internal conduit 26 Joint housing 28 Flow rate adjustment member 30 Adjuster body 32 Flow rate adjustment valve 34 Slide shaft 36 Second handle 38 Side connection portion 40 Intermediate conduit 42 Tip conduit 44 Base end straight portion 46 Tip straight portion 48 Curved portion 50 Connecting member 52 Tip nozzle portion 54 Internal space 56 Spout 58 Cooling jacket 60 Sealing member 62 Cooling cavity 64 Water supply conduit 66 Third handle 68 Drain conduit 70 Flame 72 Water tube boiler (boiler)
74 Drum (support wall member)
76 Water pipe (pipe body)
78 Mounting hole 80 Expanded portion 82 Cooling device 90 Tube heating burner (Second embodiment)
92 Tip nozzle part 94 Water supply pipe (cooling fluid pipe)
96 Drainage pipe (cooling fluid pipe)
100 Tip nozzle portion (another embodiment)
102 spout

Claims (9)

A tube heating burner,
The combustion gas outlets in the tip nozzle part of the burner body are not open in the axial direction of the tip nozzle part, but are located at multiple points in the circumferential direction on the outer circumferential surface of the tip nozzle part and are open toward the outer periphery,
In the burner body, the tip nozzle portion is provided at the tip of a gas pipe through which premixed combustion gas is introduced, and the gas pipe has a curved portion in the middle in the longitudinal direction,
a cylindrical cooling jacket that covers the outer periphery of the gas pipeline and forms a cooling cavity on the outer periphery of the gas pipeline extends from the tip nozzle portion toward the base end,
the cooling jacket includes a base-side cylindrical portion and a tip-side cylindrical portion that extend linearly from the curved portion of the gas pipeline to the base-side and tip-side ends in the length direction, respectively, and the base-side cylindrical portion and the tip-side cylindrical portion are connected to each other on the outer circumferential side of the curved portion, and the cooling cavity is formed from the curved portion of the gas pipeline to both the base-side portion and the tip-side portion,
a water supply pipe for supplying a cooling fluid to the cooling cavity is formed in the shape of a straight pipe extending from the base end toward the tip end along the gas pipe within the base end cylindrical portion of the cooling jacket, and the water supply pipe opens toward the inner circumferential surface of the tip end cylindrical portion at the tip portion of the base end cylindrical portion, so that the cooling fluid supplied through the water supply pipe is discharged toward the inner circumferential surface of the tip end cylindrical portion,
The tube-heating burner has a drainage pipe provided in the base end cylindrical portion for draining the cooling fluid from the cooling cavity . The plurality of nozzle holes are located at a plurality of positions spaced apart from each other in the circumferential direction of the tip nozzle portion,
2. A tube heating burner according to claim 1, wherein the plurality of nozzle holes are provided at four or more locations around the periphery of the tip nozzle, and are evenly spaced around the periphery of the tip nozzle. A tube heating burner as described in claim 1 or 2, wherein the nozzle holes are located at multiple locations axially spaced apart from one another in the tip nozzle portion, and at multiple locations circumferentially. A tube heating burner as described in claim 3, wherein the plurality of nozzle holes provided on adjacent circumferential lines in the axial direction of the tip nozzle portion are located at multiple locations spaced apart from one another on the circumferential lines, and the nozzle holes located on each circumferential line are offset from one another in the circumferential direction so as not to overlap one another when projected in the axial direction. A tube heating burner as described in any one of claims 1 to 4, wherein the nozzle is open in the radial direction of the tip nozzle portion. A tube heating burner as described in any one of claims 1 to 5, wherein the opening area of the nozzle is 1/5 or less of the cross-sectional area of the flow path of the combustion gas inside the tip nozzle portion. the tip nozzle portion is provided at a tip of the gas pipeline, and has a block-like shape with a peripheral wall thicker than the gas pipeline;
the cooling cavity into which the cooling fluid is guided is formed so as to surround the periphery of the gas pipe at least at a tip portion of the gas pipe,
A tube heating burner described in any one of claims 1 to 6, wherein the wall portion at the tip side of the cooling cavity is formed by the tip nozzle portion, so that the cooling cavity reaches the tip nozzle portion. 8. A tube heating burner as described in claim 7, wherein the tip end portion of the gas pipe including the tip nozzle portion extends at an incline relative to the base end portion of the gas pipe which extends linearly and constitutes a joint portion which is gripped by an operator. A tube heating burner as described in claim 7 or 8, wherein the cooling fluid pipe through which the cooling fluid flows is housed together with the gas pipe in a joint housing, forming a joint portion that is gripped by an operator.