JP6543452B2 - Heat exchanger tube repair method for heat exchanger and insertion tube for heat exchanger tube repair - Google Patents

Description

  The present invention relates to a heat exchanger tube repair method for a heat exchanger, and an insertion tube for heat exchanger tube repair.

  For example, the waste incinerator shown in Patent Document 1 includes an air preheater that heats the air introduced into the combustion chamber using the combustion exhaust gas.

  The air preheater is configured to include, for example, a large number of heat transfer tubes. Each heat transfer tube has a linear shape, and is installed in the flue (passage) of the waste incinerator in a posture perpendicular to the exhaust gas discharge direction. The outer surface of each heat transfer tube is exposed to the high temperature flue gas passing through the flue, and heat exchange is performed between the low temperature air introduced into the interior of each heat transfer tube and the high temperature flue gas. Is done.

  Patent Document 2 describes a heat recovery heat exchanger that recovers the heat of combustion exhaust gas. The heat recovery heat exchanger is configured to include a ceramic case exposed to the combustion exhaust gas and a flow path member covered with the ceramic case and through which water vapor flows, and between the combustion exhaust gas and the water vapor Heat exchange takes place.

[Patent Document 1] Japanese Patent Application Publication No. 2007-057113 (see FIG. 7, paragraph 0014) JP, 2014-43994, A (refer to Drawing 3, paragraphs 0034-0046)

  In the conventional example according to Patent Document 1, dew condensation is generated on the outer surface of the heat transfer pipe by cooling the high temperature combustion exhaust gas contacting the outer surface of the heat transfer pipe by the low temperature air introduced into the heat transfer pipe. There is.

  If the combustion exhaust gas contains a component (such as chlorine or sulfur) that corrodes a metal, the heat transfer tube is corroded because the corrosion component is mixed with the water generated by the condensation. As a result, there is a risk that the wall thickness may decrease if it is terrible.

  In view of such circumstances, it is an object of the present invention to provide a heat exchanger tube repairing method for a heat exchanger which can suppress or prevent the progress of corrosion due to condensation of the heat exchanger tube. Another object of the present invention is to provide an insertion tube suitable for use in the heat transfer tube repair method.

The present invention exchanges heat between combustion exhaust gas flowing in a passage member and air introduced into a straight heat transfer pipe attached to the passage member so as to be orthogonal to the flow direction of the combustion exhaust gas. A method of repairing the heat transfer pipe by inserting a straight insertion pipe set to an outer diameter size smaller than an inner diameter size of the heat transfer pipe into the heat transfer pipe of the heat exchanger, On the one end side in the longitudinal direction of the tube, there is provided an enlarged diameter portion which gradually expands in diameter toward the end edge, and in the longitudinal direction of this insertion tube, a ring- like bulging projecting in a radially outward direction Is a protrusion provided, and the maximum outer diameter dimension of the bulging portion is set to be the same as the maximum outer diameter dimension of the enlarged diameter portion, or is it slightly smaller than the inner diameter dimension of the heat transfer tube? Or the same as the inner diameter of the heat transfer tube When repairing the heat transfer tube, the insertion tube is inserted into the heat transfer tube, and the other end side in the longitudinal direction of the insertion tube is supported by the end portion on the air introduction side of the heat transfer tube. The expanded diameter portion of the pipe is disposed at a predetermined position that is located inside from the edge on the air discharge side in the heat transfer pipe, and the bulging portion is disposed at a predetermined position that is further interiorly located than the expanded diameter portion. An annular gap is formed between the outer circumferential surface of the insertion tube and the inner circumferential surface of the heat transfer tube.

  Here, when the heat transfer pipe is repaired using the insertion pipe, for example, when the outer surface of the heat transfer pipe corrodes, a gap formed between the heat transfer pipe and the insertion pipe exerts a heat insulating function. The high temperature combustion exhaust gas flowing in the passage member is unlikely to be rapidly cooled by the low temperature air introduced into the insertion tube when the heat transfer tube is touched.

  As a result, the occurrence of condensation on the outer surface of the heat transfer tube is suppressed or prevented, so that the development of corrosion on the outer surface of the heat transfer tube is suppressed or prevented.

  However, in the above configuration of the present invention, the heat exchange efficiency between the high temperature combustion exhaust gas flowing in the passage member and the low temperature air introduced into the insertion pipe is reduced as compared with the case where the gap is not provided. It is preferable to appropriately design the dimension of the gap in consideration of the heat exchange efficiency and the heat insulating effect, since this can not be avoided.

Furthermore, in the above configuration, an annular gap can be easily formed between the heat transfer pipe and the insertion pipe by the enlarged diameter portion and the bulging portion of the insertion pipe, and the clearance can be made substantially constant. It will be easy to keep.

Further, according to the present invention, heat exchange is performed between the combustion exhaust gas flowing in the passage member and the air introduced into the heat transfer pipe in a straight shape attached to the passage member so as to be orthogonal to the flow direction of the combustion exhaust gas. The heat exchanger is a straight insertion tube inserted into the heat transfer tube when repairing the heat transfer tube, the outside diameter of the insertion tube being set smaller than the inside diameter of the heat transfer tube. An enlarged diameter portion gradually increasing in diameter toward the end edge is provided on one end side in the longitudinal direction of the insertion tube, and the insertion tube is projected so as to be tapered radially outward in the middle of the longitudinal direction The ring-shaped bulging portion is provided, and the maximum outer diameter of the bulging portion is set to be the same as the maximum outer diameter of the enlarged diameter portion, and is slightly smaller than the inner diameter of the heat transfer tube Small or set equal to the inner diameter of the heat transfer tube It is characterized in that.

According to the insertion tube of such a configuration, it is possible to extend the length between the heat transfer tube and the insertion tube simply by inserting the insertion tube into the heat transfer tube by the enlarged diameter portion and the bulging portion of the insertion tube. It is possible to easily create a constant annular gap in the direction .

  Here, when the heat transfer pipe is repaired using the insertion pipe, for example, when the outer surface of the heat transfer pipe corrodes, a gap formed between the heat transfer pipe and the insertion pipe exerts a heat insulating function. The high temperature combustion exhaust gas flowing in the passage member is unlikely to be rapidly cooled by the low temperature air introduced into the insertion tube when the heat transfer tube is touched.

  As a result, the occurrence of condensation on the outer surface of the heat transfer tube is suppressed or prevented, so that the development of corrosion on the outer surface of the heat transfer tube is suppressed or prevented.

  The present invention can provide a heat exchanger tube repairing method for a heat exchanger capable of suppressing or preventing the development of corrosion due to condensation on the outer surface of the heat exchanger tube. Further, the present invention can provide an insertion tube suitable for use in the heat transfer tube repair method.

It is a side view showing one embodiment of a heat exchanger to which the present invention is applied. It is the figure which looked at the heat exchanger of FIG. 1 from the air introduction side. FIG. 3 is a cross-sectional view showing a state in which one of a large number of heat transfer tubes installed in the heat exchanger of FIGS. 1 and 2 is repaired. It is a figure which shows the repair process of the heat exchanger tube of FIG. It is a perspective view of the insertion tube for repair shown in FIG. 4 single-piece | unit. FIG. 13 is a cross-sectional view showing another example of a state in which one of the heat transfer tubes installed in the heat exchanger of FIGS. 1 and 2 is repaired. It is a figure which shows the repair process of the heat exchanger tube of FIG. It is a perspective view of the insertion tube for repair shown in FIG. 7 single-piece | unit. It is a side view showing one embodiment of a heat exchanger unit to which the present invention is applied. It is sectional drawing which shows one of the heat exchanger tubes of the 1st heat exchanger arrange | positioned in the uppermost stream of FIG. It is sectional drawing which shows one of the heat exchanger tubes of the 2nd heat exchanger arrange | positioned in the middle of FIG. It is sectional drawing which shows one of the heat exchanger tubes of the 3rd heat exchanger arrange | positioned most downstream of FIG. It is sectional drawing which shows the state which repaired the heat exchanger tube of FIG. It is sectional drawing which shows the state which repaired the heat exchanger tube of FIG.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the attached drawings.

  First, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. In the figure, 1 is a passage member of combustion exhaust gas, 2 is a heat exchanger.

  The heat exchanger 2 includes a frame 3 (see FIG. 3) and a large number of heat transfer tubes 4. The frame 3 is formed in a rectangular tube shape, and is disposed to communicate with the passage member 1. The heat transfer tubes 4 are each formed in a linear shape, and are in a posture perpendicular to the flow direction of the combustion exhaust gas, and are attached in the frame 3 in a state of being arranged in large numbers in the vertical and horizontal directions. It goes without saying that the orthogonal posture includes a slight misalignment or the like.

  Specifically, the heat transfer tubes 4 are arranged side by side in a state of being separated for a predetermined period in the adjacent direction (horizontal direction) and the circulation direction (longitudinal direction) of the combustion exhaust gas.

  The heat transfer tube 4 is bridged across the first wall 3 a and the second wall 3 b opposed in parallel in the frame 3. In the first and second wall portions 3a and 3b, first and second through holes 3c and 3d penetrating in the thickness direction are provided.

  One end side of the heat transfer tube 4 in the longitudinal direction is attached to penetrate the first through hole 3 c of the first wall 3 a of the frame 3, and the other end side of the heat transfer tube 4 is the second wall of the frame 3 It is attached to the second through hole 3d of 3b in a penetrating manner.

  The heat transfer tube 4 is formed of, for example, a steel material excellent in sulfuric acid dew point corrosion resistance, for example, a metal such as carbon steel, chromium steel, stainless steel, etc. The first and second retaining portions 4a and 4b are provided. The first and second retaining portions 4a and 4b are shaped so as to gradually increase in diameter radially outward.

  The first and second retaining portions 4a and 4b are not formed before the heat transfer tube 4 is attached to the frame 3 and will be described later when the heat transfer tube 4 is attached to the frame 3 as described later. The heat transfer tube 4 is formed so as to prevent the heat transfer tube 4 from being removed by performing a serling process or a flare process on one end side and the other end side.

  More specifically, after inserting the one end side and the other end side of the heat transfer tube 4 in the longitudinal direction so as to protrude outside the first and second through holes 3c and 3d of the first and second wall portions 3a and 3b, The first and second retaining portions 4a and 4b are formed by performing serling processing or flare processing on one end side and the other end side of the direction, and the heat transfer tube 4 is prevented from being removed.

  Low temperature air is introduced into the inside of the heat transfer tube 4, and heat exchange is performed between the low temperature air and the high temperature flue gas. In this embodiment, the other end side of the heat transfer tube 4 in the longitudinal direction, that is, the side on which the second retaining portion 4b exists, is the air introduction side, and one end side of the heat transfer tube 4 in the longitudinal direction, that is, the first retaining portion 4a is present. Side is the air exhaust side.

  By the way, when the high-temperature combustion exhaust gas flowing in the passage member 1 touches the heat transfer pipe 4, the combustion exhaust gas is cooled by the low-temperature air introduced into the heat transfer pipe 4. Condensation may occur on the outer surface.

  Here, when the combustion exhaust gas contains a component (such as chlorine or sulfur) that corrodes a metal, the heat transfer pipe 4 is corroded because the corrosion component is mixed with the moisture to be the condensation. As a result, there is a risk that the wall thickness may decrease if it is terrible.

  As described above, when the heat transfer pipe 4 is corroded by condensation, the heat transfer pipe 4 is repaired using the repair insertion pipe 8 in order to suppress or prevent the development of the corrosion.

  The repair insertion tube 8 is formed of, for example, metal such as carbon steel for machine structure (STKM), and an enlarged diameter portion 8a gradually expanding in diameter toward the end edge is provided at one end side in the longitudinal direction thereof. .

  The maximum outer diameter D1 of the enlarged diameter portion 8a is set to be slightly smaller than the inner diameter d of the heat transfer tube 4 or equal to the inner diameter d of the heat transfer tube 4 and excluding the enlarged diameter portion 8a The outer diameter dimension D0 (also referred to as a body portion) is appropriately set smaller than the inner diameter dimension d of the heat transfer tube 4.

  When such a repair insertion tube 8 is inserted into the heat transfer tube 4, the enlarged diameter portion 8 a of the repair insertion tube 8 loose-fits or just fits on the inner circumferential surface of the heat transfer tube 4.

  And in order to fix the insertion tube 8 for repair, the heat insulating material 5 is attached to the outer side of the 2nd wall part 3b, In the through-hole 5a of this heat insulating material 5, in the insertion tube 8 for repair, rather than the 2nd wall part 3b A packing 6 for holding the heat insulating material 5 is disposed on the outer side of the heat insulating material 5 through a portion (air introduction side) protruding outward, and a pressing member 7 for holding the packing 6 on the outer side of the packing 6 Is attached.

  The pressing member 7 is, for example, a rod member having a round or square cross section, and is disposed in the area where the repair insertion pipe 8 does not exist in the packing 6, and the predetermined position in the longitudinal direction is the outer frame of the heat insulating material 5. (Not shown) is fixed.

  In this case, the length of the repair insertion tube 8 is a predetermined position at which the enlarged diameter portion 8a at one end side in the longitudinal direction of the repair insertion tube 8 is located inside the root position of the first retaining portion 4a of the heat transfer tube 4 And the other end side in the longitudinal direction of the repair insertion tube 8 is set to a length so as to be disposed at a predetermined position which protrudes outward beyond the second retaining portion 4 b of the heat transfer tube 4.

  Thus, the enlarged diameter portion 8a at one longitudinal end side of the repair insertion tube 8 is supported by the inner peripheral surface of the heat transfer tube 4, and the other longitudinal end side of the repair insertion tube 8 is supported by the heat insulator 5. Therefore, an annular gap 9 is formed between the repair insertion tube 8 and the heat transfer tube 4 and the gap 9 is kept constant.

  In this embodiment, for example, by inserting the repair insertion pipe 8 from the first retaining portion 4a side (air discharge side) of the heat transfer pipe 4 toward the second retaining portion 4b side (air introduction side), for example, as shown in FIG. As shown in FIG. 3, the repair insertion tube 8 is inserted so as to overlap in a region from the predetermined position inside the heat release pipe 4 to the second release prevention portion 4 b which is located inside the first release prevention portion 4 a .

  By the way, it is preferable to make the area | region which polymerizes the insertion tube 8 for repair with respect to the heat exchanger tube 4 as an area | region which is easy to corrode.

  Therefore, if the corrosion occurs over substantially the entire length of the heat transfer tube 4, although not shown, the repair insertion tube 8 is removed secondly from the root position of the first retaining portion 4a of the heat transfer tube 4. It is possible to set the length of the repair insertion tube 8 so as to polymerize in the area up to the end edge of the stop 4b.

  Further, if the corrosion is generated in the middle of the heat transfer tube 4 in the longitudinal direction, although not shown, the repair insertion tube 8 is not moved from the root position of the first retaining portion 4 a in the heat transfer tube 4. It is possible to set the length of the repair insertion pipe 8 so as to polymerize in a predetermined region up to the root position of the second retaining portion 4b.

  Next, a method of repairing the heat transfer tube 4 using the repair insertion tube 8 will be described.

  As shown in FIG. 2, the repair insertion pipe 8 is inserted from the side of the first retaining portion 4 a (air discharge side) of the heat transfer pipe 4. At this time, the enlarged diameter portion 8a of the repair insertion tube 8 is disposed at a predetermined position inside the root position of the first retaining portion 4a of the heat transfer tube 4, and the distal end side of the repair insertion tube 8 in the insertion direction Of the heat transfer tube 4 beyond the second retaining portion 4 b of the heat transfer tube 4. Thereby, an annular gap 9 is created between the repair insertion pipe 8 and the heat transfer pipe 4.

  The heat insulating material 5 is attached to the outside of the second wall 3b, and the portion (air introduction side) of the insertion pipe 8 for repair that protrudes outside the second wall 3b is passed through the through hole 5a of the heat insulating material 5. . A packing 6 for holding the heat insulating material 5 is disposed outside the heat insulating material 5, and a holding member 7 for holding the packing 6 is attached to the outside of the packing 6.

  When the heat transfer tube 4 is repaired in such a configuration, the annular gap 9 formed between the repair insertion tube 8 and the heat transfer tube 4 exhibits a heat insulating function, so the passage member 1 When the high-temperature combustion exhaust gas flowing inside contacts the heat transfer pipe 4, it becomes difficult to be rapidly cooled by the low temperature air introduced into the repair insertion pipe 8.

  As a result, the occurrence of condensation on the outer surface of the heat transfer tube 4 is suppressed or prevented, so that the development of corrosion on the outer surface of the heat transfer tube 4 is suppressed or prevented.

  However, when the gap 9 for exhibiting the heat insulating function is provided, it is introduced into the high temperature combustion exhaust gas and the repair insertion tube 8 circulating in the passage member 1 as compared with the case where the gap 9 is not provided. Since the reduction of the heat exchange efficiency with the low temperature air can not be avoided, it is preferable to appropriately design the dimension of the gap 9 in consideration of the heat exchange efficiency and the heat insulation effect.

  In addition, this invention is not limited only to the said embodiment, It is possible to change suitably within the range of a claim, and the range equivalent to the said range.

  (1) For the repair insertion tube 8 shown in the above embodiment, for example, as shown in FIG. 6 to FIG. 8, the bulging portion 8b protruding radially outward may be provided midway in the longitudinal direction thereof. It is possible.

  The bulging portion 8 b is provided continuously in the circumferential direction. The maximum outer diameter D2 of the bulging portion 8b is set equal to the maximum outer diameter D1 of the enlarged diameter portion 8a of the insertion tube 8 for repair, and is it slightly smaller than the inner diameter d of the heat transfer tube 4 Or, it is set equal to the inner diameter d of the heat transfer tube 4, and the outer diameter D0 of the region (also referred to as the trunk) excluding the enlarged diameter portion 8a and the bulging portion 8b is greater than the inner diameter d of the heat transfer tube 4. It is set appropriately small.

  When such a repair insertion tube 8 is used, in addition to the same operation and effect as the above embodiment can be obtained, only by inserting the repair insertion tube 8 into the heat transfer tube 4 while securing the gap 9 The gap 9 can be held constant.

  Although not shown, the bulging portion 8b may be provided discontinuously at several circumferential positions, that is, at predetermined intervals in the circumferential direction.

  (2) In the above embodiment, although one heat exchanger 2 is mentioned as an application object of the present invention as an example, the application object of the present invention is not limited only to this, for example, many heat exchange It is possible to apply the heat exchanger unit of the composition which combined the vessel to the present invention.

  As said heat exchanger unit, as shown, for example to FIGS. 9-12, what combined three 1st, 2nd, 3rd heat exchangers 20, 30, 40 can be mentioned.

  The first to third heat exchangers 20 to 40 are arranged side by side in the flow direction of the combustion exhaust gas in the passage member 1 through which the high temperature combustion exhaust gas flows.

  The first, second, and third heat exchangers 20, 30, 40 have frames 21, 31, 41 and heat transfer tubes 22, 32, 42. Each of the frames 21 to 41 is formed in a rectangular tube shape, and is disposed to communicate with the passage member 1. The heat transfer tubes 22 to 42 are each formed in a linear shape, and in a posture perpendicular to the flow direction of the combustion exhaust gas, and arranged in parallel in the vertical and horizontal directions in the frames 21 to 41 It is attached.

  Specifically, the heat transfer pipes 22 to 42 are arranged in parallel so as to be separated from each other by a predetermined interval in the adjacent direction (horizontal direction) and the circulation direction (longitudinal direction) of the combustion exhaust gas.

  Low temperature air is introduced into each of the heat transfer pipes 22 to 42, and heat exchange is performed between the low temperature air and the high temperature flue gas.

  In the heat exchanger unit having such a configuration, the heat of the combustion exhaust gas flowing in the passage member 1 is sequentially transmitted to the air sequentially introduced into the first to third heat exchangers 20 to 40. The temperature of the combustion exhaust gas gradually decreases from the upstream side to the downstream side in the flow direction in the passage member 1.

  From the relationship, the first heat exchanger 20 located most upstream in the flow direction of the combustion exhaust gas is the second heat exchanger 30 located in the middle in the flow direction of the combustion exhaust gas and the third heat exchanger located most downstream Since condensation tends to occur compared to 40, when the combustion exhaust gas contains a component (such as chlorine or sulfur) that corrodes a metal, the corrosion component is mixed with the moisture to be the condensation. In particular, the heat transfer tubes 22 of the first heat exchanger 20 are easily corroded.

  In consideration of this, the heat exchanger unit adopts the following configuration.

  First, the first heat exchanger 20 has a configuration in which the insertion pipe 26 is inserted in advance so as to form an annular gap 27 between the heat transfer pipe 22 and the inner circumferential surface of the heat transfer pipe 22. For example, as shown in FIG. 10, the insertion tube 26 is inserted in the heat transfer tube 22 so as to polymerize in a substantially full length region in the longitudinal direction. This insertion pipe 26 will be referred to as "existing insertion pipe". The fixing of the existing insertion tube 26 is performed using the heat insulating material 23, the packing 24, and the pressing member 25 as in the above embodiment.

  The second heat exchanger 30 is configured such that the insertion tube 36 is inserted in advance so as to form an annular gap 37 between the heat transfer tube 32 and the inner circumferential surface of the heat transfer tube 32. For example, as shown in FIG. 11, the insertion tube 36 is inserted in the heat transfer tube 32 so as to overlap in a region from a predetermined position inside the first retaining portion 32a to the second retaining portion 32b. ing. This insertion tube 36 is referred to as "existing insertion tube". The fixing of the existing insertion tube 36 is performed using the heat insulator 33, the packing 34, and the pressing member 35 as in the above embodiment.

  In the heat transfer tube 42 of the third heat exchanger 40, as shown in FIG. 12 in this embodiment, the existing insertion tube as described above is not inserted.

  In the case of such first and second heat exchangers 20 and 30, since the annular gaps 27 and 37 formed between the heat transfer pipes 22 and 32 and the existing insertion pipes 26 and 36 exhibit the heat insulating function, the passage The high temperature combustion exhaust gas flowing in the member 1 is less likely to be cooled by the low temperature air introduced into the existing insertion pipes 26 and 36 when the heat transfer pipes 22 and 32 are touched.

  As a result, the occurrence of condensation on the outer surfaces of the heat transfer tubes 22 and 32 of the first and second heat exchangers 20 and 30 is suppressed or prevented, so that corrosion occurs on the outer surfaces of the heat transfer tubes 22 and 32. Will be suppressed or prevented.

  However, in the case where the gaps 27 and 37 for exhibiting the heat insulating function are provided, the high temperature combustion exhaust gas circulating in the passage member 1 and the existing insertion tube 26 are compared with the case where the gaps 27 and 37 are not provided. Since it is inevitable that the heat exchange efficiency with the low temperature air introduced into the air 36 is reduced, the dimensions of the gaps 27 and 37 are appropriately designed in consideration of the heat exchange efficiency and the heat insulating function. It is preferable to do.

  By the way, if a portion of the heat transfer tube 32 of the second heat exchanger 30 shown in FIG. 11 where the existing insertion tube 36 does not exist is corroded due to the condensation, as shown in FIG. In order to suppress or prevent the development of corrosion on the outer surface of the heat transfer tube 32 of the second heat exchanger 30, a repair insertion tube 38 can be inserted.

  The repair insertion tube 38 is provided with enlarged diameter portions 38a and 38b that gradually increase in diameter toward the respective end edges on one end side and the other end side in the longitudinal direction. That is, the repair insertion tube 38 is arranged so as to loose fit or just fit the enlarged diameter portions 38 a and 38 b at both ends in the longitudinal direction to the inner peripheral surface of the heat transfer tube 32.

  Then, in the example shown in FIG. 13, the repair insertion pipe 38 is disposed in the heat transfer pipe 32 so as to be adjacent to the existing insertion pipe 36.

  Thus, it is possible to form an annular gap 39 between the heat transfer tube 32 and the repair insertion tube 38, and to keep the gap 39 constant. However, the length of the repair insertion pipe 38 may be appropriately set in accordance with the corrosion range.

  On the other hand, with regard to the third heat exchanger 40 shown in FIG. 12, the existing insertion pipe as described above is not inserted, but the combustion exhaust gas touching the third heat exchanger 40 and the heat transfer tubes of the third heat exchanger 40 Since the temperature difference between the air introduced into the heat exchanger 42 and the temperature of the air introduced into the heat exchanger 42 is smaller than that of the first and second heat exchangers 20 and 30, the heat transfer tube 42 of the third heat exchanger 40 Condensation is less likely to occur.

  However, if the predetermined area of the heat transfer tube 42 of the third heat exchanger 40 is corroded due to the condensation, as shown in FIG. 14, the progress of corrosion in the heat transfer tube 42 of the third heat exchanger 40 is The repair insertion tube 46 can be inserted into the heat transfer tube 42 of the third heat exchanger 40 in order to suppress or prevent it.

  The repair insertion tube 46 is provided with an enlarged diameter portion 46a which gradually expands toward the end edge only at one end side in the longitudinal direction. That is, the repair insertion tube 46 is inserted such that the enlarged diameter portion 46a at one end in the longitudinal direction is loose fit or just fit on the inner circumferential surface of the heat transfer tube 42, and the other end in the longitudinal direction It is positioned by being inserted into the through hole 43a of the second embodiment and held by the packing 44 and the pressing member 45 so as to be prevented.

  And in the example shown in FIG. 14, the insertion tube 46 for repair is inserted in the heat transfer tube 42 so as to overlap in the region from the predetermined position where it entered inside the first retaining portion 42a to the second retaining portion 42b. It is done.

  As a result, after the annular gap 47 is formed between the heat transfer tube 42 and the repair insertion tube 46, the gap 47 can be kept constant. However, the length of the repair insertion pipe 46 may be set appropriately according to the corrosion area.

  (3) Although the repair insertion pipes 38 and 46 shown in the above (2) are not shown, in the middle of the longitudinal direction thereof, a bulging part similar to the bulging part 8b described in the above (1) It is possible to provide.

  The present invention is a heat exchange for exchanging heat between combustion exhaust gas flowing in a passage member and air introduced into a heat transfer pipe attached to the passage member in a posture orthogonal to the flow direction of the combustion exhaust gas. It is possible to utilize suitably as a method of repairing the above-mentioned heat transfer tube of a vessel. Further, the present invention can be suitably used as an insertion pipe used for repairing the heat transfer pipe.

1 passage member
2 Heat exchanger
3 frame
3a first wall
3b second wall
3c 1st through hole
3d second through hole
4 Heat transfer tube
4a 1st retaining part
4b 2nd retaining part
5 Insulation material
5a through hole
6 Packing
7 Holding member
8 Repairing insertion tube
8a Expanded diameter section
9 gap

Claims (2)

A heat exchanger for exchanging heat between combustion exhaust gas flowing in a passage member and air introduced into a straight heat transfer pipe attached to the passage member so as to be orthogonal to the flow direction of the combustion exhaust gas A method of repairing the heat transfer tube by inserting a straight insertion tube set to an outer diameter dimension smaller than an inner diameter dimension of the heat transfer tube into the heat transfer tube;
An enlarged diameter portion gradually increasing in diameter toward the end edge is provided on one end side in the longitudinal direction of the insertion tube, and the end of the insertion tube protrudes so as to be tapered radially outward in the longitudinal direction An annular bulging portion is provided, and the maximum outer diameter dimension of the bulging portion is set to be the same as the maximum outer diameter dimension of the enlarged diameter portion, and is slightly smaller than the inner diameter dimension of the heat transfer tube Or smaller than the inner diameter of the heat transfer tube,
When repairing the heat transfer tube, the insertion tube is inserted into the heat transfer tube, and the other end side in the longitudinal direction of the insertion tube is supported by the end portion on the air introduction side of the heat transfer tube. The expanded diameter portion of the pipe is disposed at a predetermined position that is located inside from the edge on the air discharge side in the heat transfer pipe, and the bulging portion is disposed at a predetermined position that is further interiorly located than the expanded diameter portion. A heat exchanger tube repairing method for a heat exchanger, wherein an annular gap is formed between an outer peripheral surface of the insertion tube and an inner peripheral surface of the heat transfer tube. A heat exchanger for exchanging heat between combustion exhaust gas flowing in a passage member and air introduced into a straight heat transfer pipe attached to the passage member so as to be orthogonal to the flow direction of the combustion exhaust gas A straight insertion tube inserted into the heat transfer tube when repairing the heat transfer tube;
The outside diameter size is set smaller than the inside diameter size of the heat transfer tube,
An enlarged diameter portion gradually increasing in diameter toward the end edge is provided on one end side in the longitudinal direction of the insertion tube, and the end of the insertion tube protrudes so as to be tapered radially outward in the longitudinal direction An annular bulging portion is provided,
The maximum outer diameter of the bulging portion is set to be the same as the maximum outer diameter of the enlarged diameter portion and is slightly smaller than the inner diameter of the heat transfer tube, or the same as the inner diameter of the heat transfer tube An insertion tube for heat transfer tube repair characterized in that.

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