A detection tool for the welded nozzle of a bayonet tube heat exchanger and its detection method

Abstract

A detection tool and its detection method for the welded pipe orifices of a bayonet tube heat exchanger, which relates to the technical field of pressure vessel manufacturing. The present invention solves the problem that the existing tooling for the weld leakage test of conventional heat exchangers cannot detect the welds after welding of the sheath tube, tube sheet of the bayonet tube heat exchanger, and the welds after welding of the sheath tube and heat exchange tube. The present invention includes a short detection tool and an extended detection tool. For the case where the tube extension length is small or there is no extension, one set screw can be used to achieve simultaneous sealing of the two; for the case where the tube extension length is too long, two set screws are required to achieve effective sealing. By adopting a step-by-step detection method, the welds after welding of the sheath tube, tube sheet, and the welds after welding of the sheath tube and heat exchange tube are respectively detected, improving the detection efficiency and quality of the welds of the tube sheet, heat exchange tube, and sheath tube. The present invention is used for the leakage test and pressure test of the tube sheet, heat exchange tube, and sheath tube of the bayonet tube structure of petrochemical heat exchanger products.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure vessel manufacturing, and particularly relates to a detection tool and a detection method for the welded joints of the nozzle of a bayonet tube heat exchanger after welding. Background Art

[0002] For a certain bayonet tube product, the tube sheet a, the heat exchange tube b, and the protection sleeve c have a complex structure, and there are significant differences from the nozzle connections of conventional heat exchangers. For this bayonet tube product, an additional layer of protection sleeve c is added between the heat exchange tube b and the tube sheet a. The protection sleeve c is welded to one end of the tube sheet a, and the other end is free to expand and contract. The heat exchange tube b is inserted into the protection sleeve c and is welded to the protection sleeve c on one side (see Figure 1 ). Since the quality of these two welds directly determines whether the equipment can be used normally, leakage tests are proposed in the design. However, due to the narrow space and the excessive length of the extension of the heat exchange tube b, the test methods of conventional heat exchangers cannot be used.

[0003] Considering the special structure of this equipment: circular tube arrangement, the outer tubes (protection sleeves c) surround the inner tubes (heat exchange tubes b). If there are welding quality problems with the inner tubes (heat exchange tubes b), the product will be scrapped due to the lack of repair space. Therefore, it is necessary to detect each tube from the inside out and ensure the qualification of the welding before proceeding with the welding of the next tube. There are hundreds to thousands of heat exchange tubes b of this type of product, and each heat exchange tube b has two welds. Leakage tests need to be performed on each one. As simple tooling is required as much as possible, there is an urgent need in the process for a detection tool and a detection method for the welded joints of the nozzle of a bayonet tube heat exchanger after welding.

[0004] In summary, the existing tooling for the leakage test of the welds of conventional heat exchangers has the problem that it cannot detect the welds after welding between the protection sleeve c and the tube sheet a, and between the protection sleeve c and the heat exchange tube b of the bayonet tube heat exchanger. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing tooling for the leakage test of the welds of conventional heat exchangers cannot detect the welds after welding between the protection sleeve c and the tube sheet a, and between the protection sleeve c and the heat exchange tube b of the bayonet tube heat exchanger, and further provide a detection tool and a detection method for the welded joints of the nozzle of a bayonet tube heat exchanger after welding.

[0006] The technical solution of the present invention is as follows:

[0007] A detection tool for the welded joint of the bayonet tube heat exchanger nozzle, which includes a pull rod 1, a sealing sleeve 2, a pressing block 3, an end sealing ring 4, a connecting head 5, a gasket 6, a set screw nut 7, a clamp 8, an intermediate sealing ring 9 and a transition joint 10. The pressing block 3 is of a T-shaped step sleeve structure. The sealing sleeve 2, the pressing block 3 and the gasket 6 are sleeved on the rod section of the pull rod 1 in sequence from front to back. One end of the sealing sleeve 2 far from the pressing block 3 abuts against the end cap of the pull rod 1. The middle part of the rod section of the pull rod 1 is processed with an external thread. The connecting head 5 is of a stepped sleeve shape with variable diameter. The connecting head 5 is sleeved outside the pressing block 3 and the gasket 6. An end sealing ring 4 is installed at the large-diameter end of the connecting head 5. A end cover is integrally formed at the small-diameter end of the connecting head 5. A plurality of ventilation holes are evenly processed on the circumference of the end cover. A round hole matching the rod section of the pull rod 1 is processed at the center of the end cover. The set screw nut 7 is threadedly connected with the rod section of the pull rod 1. The sealing sleeve 2, the pressing block 3, the gasket 6 and the end cover of the connecting head 5 are axially pressed by the set screw nut 7. The transition joint 10 is of a circular sleeve structure with one end closed. A pipeline joint for communicating with the outside is integrally formed at the center of the closed end of the transition joint 10. The transition joint 10 is sleeved at the end of the rod section of the pull rod 1. An intermediate sealing ring 9 is arranged between the open end face of the transition joint 10 and the small-diameter end face of the connecting head 5. The transition joint 10 and the connecting head 5 are detachably connected by a clamp 8.

[0008] Further, the connecting head 5 is a short connecting head. The outer diameter of the sealing sleeve 2 in the non-extruded state and the inner diameter of the protective sleeve c are in clearance fit. When the sealing sleeve 2 is completely inserted into the inner hole of the protective sleeve c, the length of the part of the protective sleeve c extending out of the tube sheet a away from the weld is less than the length of the connecting head 5. At this time, the detection tool is a short detection tool, and the short detection tool is used for detecting the weld of the protective sleeve c and the tube sheet a after welding.

[0009] Further, the connecting head 5 is an extended connecting head. The outer diameter of the sealing sleeve 2 in the non-extruded state and the inner diameter of the heat exchange tube b are in clearance fit. When the sealing sleeve 2 is completely inserted into the inner hole of the heat exchange tube b, the length of the part of the heat exchange tube b extending out of the tube sheet a away from the weld is less than the length of the connecting head 5. At this time, the detection tool is an extended detection tool, and the extended detection tool is used for detecting the weld of the protective sleeve c and the heat exchange tube b after welding.

[0010] Further, a rectangular block matching the clamping part of the wrench is processed at the end of the rod section of the pull rod 1.

[0011] Further, the outer diameter of the end cap of the pull rod 1 is d 1 , the outer diameter of the sealing sleeve 2 is d 2 , the inner diameter of the sealing sleeve 2 is d 3 , d 3 ≥d 1 ≥d 2 .

[0012] Further, the pull rod 1, the pressing block 3, and the connector 5 are all made of stainless steel.

[0013] Further, the sealing sleeve 2, the end sealing ring 4, and the intermediate sealing ring 9 are all made of rubber.

[0014] Further, the gasket 6 is made of copper.

[0015] Further, it further includes a drain screw 11. A threaded hole is machined on one side of the outer cylindrical surface of the connector 5 close to the tube sheet. The drain screw 11 is threadedly and sealingly installed in the threaded hole of the connector 5.

[0016] A detection method for a detection tool after welding the nozzle of a bayonet tube heat exchanger according to the ninth specific embodiment. The detection method for the nozzle of the bayonet tube heat exchanger after welding is realized through the following steps.

[0017] Step 1: Use a short detection tool to detect the welds after welding of the protective sleeve c and the tube sheet a.

[0018] First, before detecting the welds after welding of the protective sleeve c and the tube sheet a, insert the protective sleeve c into the tube sheet a and weld it to the protective sleeve c.

[0019] Then, assemble the pull rod 1, the sealing sleeve 2, the pressing block 3, the gasket 6, and the set nut 7 of the short detection tool into a component and insert it into the protective sleeve c. At this time, the sealing sleeve 2 of the short detection tool is completely inserted into the protective sleeve c.

[0020] Further, sleeved the connector 5 with the end sealing ring 4 on the protective sleeve c. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating. Use another wrench to tighten the set nut 7, so that the sealing sleeve 2 expands radially under the extrusion of the pressing block 3, the gasket 6, and the connector 5 to achieve a tight fit with the inner hole of the protective sleeve c. At the same time, the connector 5 approaches the end face of the tube sheet a under the action of the set nut 7 and presses the end sealing ring 4 tightly.

[0021] Furthermore, sleeved the transition joint 10 on the end of the pull rod 1, place the intermediate sealing ring 9 between the transition joint 10 and the connector 5, and connect the transition joint 10 and the connector 5 with a clamp 8.

[0022] Finally, connect the pipeline joint at the end of the transition joint 10 to the external helium leak detection pipeline or the water pressure device. After the gas or water is introduced for a period of time, tighten the drain screw 11 to perform a leak test or a pressure test on the welds after welding of the protective sleeve c and the tube sheet a. When the detection of the welds after welding of the protective sleeve c and the tube sheet a is completed, disassemble the short detection tool.

[0023] Step 2: Use an extended detection tool to detect the welds after welding of the protective sleeve c and the heat exchange tube b.

[0024] First, before detecting the post-weld seams of the protective sleeve c and the heat exchange tube b, insert the heat exchange tube b into the protective sleeve c and perform single-sided welding with the protective sleeve c;

[0025] Then, assemble the pull rod 1, the sealing sleeve 2, the pressing block 3, the gasket 6, and the set screw 7 of the extended detection tool into a component and insert it into the heat exchange tube b. At this time, the sealing sleeve 2 of the extended detection tool is completely inserted into the heat exchange tube b. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating, and use another wrench to tighten a set screw 7 so that the sealing sleeve 2 expands radially under the extrusion of the pressing block 3 and the gasket 6 to achieve a tight fit with the inner hole of the heat exchange tube b;

[0026] Furthermore, sleeved the connector 5 equipped with the end sealing ring 4 on the heat exchange tube b. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating, and use another wrench to tighten another set screw 7 so that the connector 5 approaches the end face of the tube sheet a under the action of the set screw 7 and presses the end sealing ring 4;

[0027] Even further, sleeved the adapter 10 on the end of the pull rod 1, placed the intermediate sealing ring 9 between the adapter 10 and the connector 5, and connected the adapter 10 and the connector 5 with a clamp 8;

[0028] Finally, connect the pipeline joint at the end of the adapter 10 to the external helium leak detection pipeline or the water pressure device. After passing gas or water for a period of time, tighten the drain screw 11 to perform a leak test or a pressure test on the post-weld seams of the protective sleeve c and the heat exchange tube b. When the detection of the post-weld seams of the protective sleeve c and the heat exchange tube b is completed, disassemble the extended detection tool;

[0029] So far, the detection of the post-weld seams of the protective sleeve c and the tube sheet a, as well as the post-weld seams of the protective sleeve c and the heat exchange tube b, has been completed.

[0030] The present invention has the following effects compared with the prior art:

[0031] 1. The detection tool for the pipe orifice after welding of the bayonet tube heat exchanger of the present invention includes a short detection tool and an extended detection tool. For the case where the tube extension length is small or there is no extension, one set screw can be used to achieve simultaneous sealing of both; for the case where the tube extension length is too long, two set screws are required to achieve effective sealing. By adopting a step-by-step detection method, the post-weld seams of the protective sleeve, the tube sheet, as well as the post-weld seams of the protective sleeve and the heat exchange tube are detected respectively; not only improves the detection efficiency and quality of the seams of the tube sheet, the heat exchange tube, and the protective sleeve, but also is convenient to use, simple to operate, and the tooling manufacturing cost is low.

[0032] 2. The present invention adopts a simple expansion plug + sealing ring structure, and forms a sealed chamber through threaded fastening to realize the detection of a single tube;

[0033] 3. When the lengthened inspection tool is used in the present invention to inspect the weld seam after welding the protection sleeve c and the heat exchange tube b, a leak test with greater pressure is achieved by adding a set screw 7.

[0034] 4. By increasing the length of the connector 5 in the present invention, the inspection of the weld seam between the heat exchange tube b and the protection sleeve c when the heat exchange tube b extends too long can be solved.

[0035] 5. The present invention uses a clamp 8 and an adapter 10 to achieve quick sealing, and can easily achieve the inspection of leak tests and pressure tests. Select a clamp-type quick-change connector and adopt a standard size design. The clamps are purchased as standard products, which can achieve quick installation and disassembly and have strong versatility. Brief Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the tube sheet a, the heat exchange tube b, and the protection sleeve c of the present invention;

[0037] Figure 2 It is a cross-sectional view (short type) of the inspection tool for the welded joint of the bayonet tube heat exchanger of the present invention;

[0038] Figure 3 It is a cross-sectional view (lengthened type) of the inspection tool for the welded joint of the bayonet tube heat exchanger of the present invention;

[0039] Figure 4 It is a front view of the clamp of the present invention;

[0040] Figure 5 It is a side view of the clamp of the present invention;

[0041] Figure 6 It is a cross-sectional view of the adapter of the present invention;

[0042] Figure 7 It is a sequence diagram of the use of the cross-sectional view (short type) of the inspection tool for the welded joint of the bayonet tube heat exchanger of the present invention;

[0043] Figure 8 It is a schematic diagram of the use of the cross-sectional view (short type) of the inspection tool for the welded joint of the bayonet tube heat exchanger of the present invention;

[0044] Figure 9 It is a schematic diagram of the use of the cross-sectional view (lengthened type) of the inspection tool for the welded joint of the bayonet tube heat exchanger of the present invention.

[0045] In the figure: 1 - pull rod; 2 - sealing sleeve; 3 - pressing block; 4 - end sealing ring; 5 - connector; 6 - gasket; 7 - set screw; 8 - clamp; 9 - intermediate sealing ring; 10 - adapter; 11 - drain screw; a - tube sheet; b - heat exchange tube; c - protection sleeve. Detailed Embodiments

[0046] Detailed Embodiment 1: In combination withFigures 1 to 9 Regarding this embodiment, a detection tool for a bayonet tube heat exchanger after welding of the pipe orifice in this embodiment includes a pull rod 1, a sealing sleeve 2, a pressing block 3, an end sealing ring 4, a connector 5, a gasket 6, a set screw nut 7, a clamp 8, an intermediate sealing ring 9, and a transition joint 10. The pressing block 3 is of a T-shaped stepped sleeve structure. The sealing sleeve 2, the pressing block 3, and the gasket 6 are sleeved on the rod section of the pull rod 1 in sequence from front to back. One end of the sealing sleeve 2 away from the pressing block 3 abuts against the end cap of the pull rod 1. An external thread is machined in the middle of the rod section of the pull rod 1. The connector 5 is of a stepped sleeve shape with variable diameter. The connector 5 is sleeved outside the pressing block 3 and the gasket 6. An end sealing ring 4 is installed at the large-diameter end of the connector 5. A end cover is integrally formed at the small-diameter end of the connector 5. A plurality of ventilation holes are uniformly machined along the circumferential direction on the end cover. A round hole matching the rod section of the pull rod 1 is machined at the center of the end cover. The set screw nut 7 is in threaded connection with the rod section of the pull rod 1. The sealing sleeve 2, the pressing block 3, the gasket 6, and the end cover of the connector 5 are axially pressed through the set screw nut 7. The transition joint 10 is of a circular sleeve structure with one end closed. A pipeline joint for communicating with the outside is integrally formed at the center of the closed end of the transition joint 10. The transition joint 10 is sleeved on the end of the rod section of the pull rod 1. An intermediate sealing ring 9 is provided between the open end face of the transition joint 10 and the small-diameter end face of the connector 5. The transition joint 10 and the connector 5 are detachably connected through the clamp 8.

[0047] Specific Embodiment Two: Combining Figure 2 and Figure 8 Regarding this embodiment, the connector 5 in this embodiment is a short connector. The outer diameter of the sealing sleeve 2 in the non-extruded state and the inner diameter of the protective sleeve c are in clearance fit. When the sealing sleeve 2 is completely inserted into the inner hole of the protective sleeve c, the length of the part of the protective sleeve c extending out of the tube sheet a away from the weld is less than the length of the connector 5. At this time, the detection tool is a short detection tool, and the short detection tool is used for detecting the weld of the protective sleeve c and the tube sheet a after welding. With such a setting, for tubes with a small or non-extending length, one set screw can be used to achieve simultaneous sealing of both. Other compositions and connection relationships are the same as those in Specific Embodiment One.

[0048] Specific Embodiment Three: Combining Figure 3 and Figure 9 Regarding this embodiment, the connector 5 in this embodiment is an extended connector. The outer diameter of the sealing sleeve 2 in the non-extruded state and the inner diameter of the heat exchange tube b are in clearance fit. When the sealing sleeve 2 is completely inserted into the inner hole of the heat exchange tube b, the length of the part of the heat exchange tube b extending out of the tube sheet a away from the weld is less than the length of the connector 5. At this time, the detection tool is an extended detection tool, and the extended detection tool is used for detecting the weld of the protective sleeve c and the heat exchange tube b after welding. With such a setting, for tubes with an overly long extending length, two set screws are required to achieve effective sealing. Other compositions and connection relationships are the same as those in Specific Embodiment One or Two.

[0049] Embodiment 4: With reference to Figure 2 and Figure 3 describe this embodiment. A rectangular block matching the wrench clamping part is machined at the end of the rod section of the pull rod 1 in this embodiment. With such a setting, while using a wrench to tightly fasten the lock nut 7, another wrench is also needed to tightly fasten the rectangular block at the end of the pull rod 1 to prevent the pull rod 1 from rotating. The other components and connection relationships are the same as those in Embodiment 1, 2 or 3.

[0050] Embodiment 5: With reference to Figure 2 and Figure 3 describe this embodiment. The outer diameter of the end cap of the pull rod 1 in this embodiment is d 1 , the outer diameter of the sealing sleeve 2 is d 2 , the inner diameter of the sealing sleeve 2 is d 3 , d 3 ≥d 1 ≥d 2 . With such a setting, the end cap of the pull rod 1 plays an axial positioning role for the sealing sleeve 2. The other components and connection relationships are the same as those in Embodiment 1, 2, 3 or 4.

[0051] Embodiment 6: With reference to Figure 2 and Figure 3 describe this embodiment. The pull rod 1, the pressure block 3 and the connector 5 in this embodiment are all made of stainless steel. With such a setting, considering the cleaning requirements of the product and avoiding ferrite contamination, stainless steel is selected. The other components and connection relationships are the same as those in Embodiment 1, 2, 3, 4 or 5.

[0052] Embodiment 7: With reference to Figure 2 and Figure 3 describe this embodiment. The sealing sleeve 2, the end sealing ring 4 and the middle sealing ring 9 in this embodiment are all made of rubber. With such a setting, a simple expansion plug + sealing ring structure is adopted, and a closed cavity is formed through thread fastening to realize the detection of a single pipe. The other components and connection relationships are the same as those in Embodiment 1, 2, 3, 4, 5 or 6.

[0053] Embodiment 8: With reference to Figure 2 and Figure 3 describe this embodiment. The gasket 6 in this embodiment is made of copper. With such a setting, considering the cleaning requirements of the product and avoiding ferrite contamination, copper is selected. The other components and connection relationships are the same as those in Embodiment 1, 2, 3, 4, 5, 6 or 7.

[0054] Embodiment 9: With reference to Figure 2 and Figure 3Regarding this embodiment, this embodiment further includes a drain screw 11. A threaded hole is machined on the outer cylindrical surface of the connector 5 on the side close to the tube sheet. The drain screw 11 is threadedly and sealingly installed in the threaded hole of the connector 5. With such a setting, when the adapter 10 is connected to the helium leak detection pipeline or the water pressure device, after the gas or water has been introduced for a period of time, the drain screw 11 is tightened for a leak test or a pressure test. The drain screw 11 can also be changed to a high-pressure water pipe structure to facilitate drainage and exhaust. The other components and connection relationships are the same as those in the first, second, third, fourth, fifth, sixth, seventh, or eighth specific embodiments.

[0055] Specific Embodiment Ten: Combining Figures 1 to 9 Regarding this embodiment, a detection method of a detection tool for the welded joints of the bayonet tube heat exchanger nozzles described in Specific Embodiment Nine is provided. The detection method for the welded joints of the bayonet tube heat exchanger nozzles is realized through the following steps:

[0056] Step 1. Use a short detection tool to detect the welds after welding of the protection sleeve c and the tube sheet a:

[0057] First, before detecting the welds after welding of the protection sleeve c and the tube sheet a, insert the protection sleeve c into the tube sheet a and weld it to the protection sleeve c;

[0058] Then, assemble the pull rod 1, the sealing sleeve 2, the pressing block 3, the gasket 6, and the set nut 7 of the short detection tool into a component and insert it into the protection sleeve c. At this time, the sealing sleeve 2 of the short detection tool is completely inserted into the protection sleeve c;

[0059] Furthermore, sleeved the connector 5 with the end sealing ring 4 on the protection sleeve c. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating, and use another wrench to tighten the set nut 7, so that the sealing sleeve 2 expands radially under the extrusion of the pressing block 3, the gasket 6, and the connector 5 to achieve a tight fit with the inner hole of the protection sleeve c. At the same time, the connector 5 approaches the end face of the tube sheet a under the action of the set nut 7 and presses the end sealing ring 4 tightly;

[0060] Even further, sleeved the adapter 10 on the end of the pull rod 1, placed the intermediate sealing ring 9 between the adapter 10 and the connector 5, and connected the adapter 10 and the connector 5 with a clamp 8;

[0061] Finally, connect the pipeline joint at the end of the adapter 10 to the external helium leak detection pipeline or the water pressure device. After the gas or water has been introduced for a period of time, tighten the drain screw 11 for a leak test or a pressure test on the welds after welding of the protection sleeve c and the tube sheet a. When the detection of the welds after welding of the protection sleeve c and the tube sheet a is completed, disassemble the short detection tool;

[0062] Step 2. Use an extended detection tool to detect the welds after welding of the protection sleeve c and the heat exchange tube b:

[0063] First, insert the heat exchange tube b into the protective sleeve c and perform single-sided welding with the protective sleeve c before detecting the post-weld seam of the protective sleeve c and the heat exchange tube b;

[0064] Then, assemble the pull rod 1, the sealing sleeve 2, the pressing block 3, the gasket 6 and the set screw nut 7 of the extended detection tool into a component and insert it into the heat exchange tube b. At this time, the sealing sleeve 2 of the extended detection tool is completely inserted into the heat exchange tube b. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating, and use another wrench to tighten a set screw nut 7 so that the sealing sleeve 2 expands radially under the extrusion of the pressing block 3 and the gasket 6 to achieve a tight fit with the inner hole of the heat exchange tube b;

[0065] Furthermore, sleeved the connector 5 equipped with the end sealing ring 4 on the heat exchange tube b. Use one wrench to tighten the end of the pull rod 1 to prevent the pull rod 1 from rotating, and use another wrench to tighten another set screw nut 7 so that the connector 5 approaches the end face of the tube sheet a under the action of the set screw nut 7 and presses the end sealing ring 4 tightly;

[0066] Even further, sleeved the transition joint 10 on the end of the pull rod 1, placed the intermediate sealing ring 9 between the transition joint 10 and the connector 5, and connected the transition joint 10 and the connector 5 with a clamp 8;

[0067] Finally, connect the pipeline joint at the end of the transition joint 10 to the external helium leak detection pipeline or the water pressure device. After passing gas or water for a period of time, tighten the drain screw 11 to perform a leak test or a pressure test on the post-weld seam of the protective sleeve c and the heat exchange tube b. When the detection of the post-weld seam of the protective sleeve c and the heat exchange tube b is completed, disassemble the extended detection tool;

[0068] So far, the detection of the post-weld seam of the protective sleeve c and the tube sheet a, as well as the post-weld seam of the protective sleeve c and the heat exchange tube b, has been completed. The other compositions and connection relationships are the same as those in the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth of the specific embodiments.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A detection tool for the welded joint of the nozzle of a bayonet tube heat exchanger, characterized in that: It includes a pull rod (1), a sealing sleeve (2), a pressing block (3), an end sealing ring (4), a connector (5), a gasket (6), a set screw nut (7), a clamp (8), an intermediate sealing ring (9) and a transition joint (10). The pressing block (3) is of a T-shaped stepped sleeve structure. The sealing sleeve (2), the pressing block (3) and the gasket (6) are sleeved on the rod section of the pull rod (1) in sequence from front to back. One end of the sealing sleeve (2) away from the pressing block (3) abuts against the end cap of the pull rod (1). The middle part of the rod section of the pull rod (1) is processed with an external thread. The connector (5) is of a reduced-diameter stepped sleeve shape. The connector (5) is sleeved outside the pressing block (3) and the gasket (6). An end sealing ring (4) is installed at the large-diameter end of the connector (5). An end cover is integrally formed at the small-diameter end of the connector (5). A plurality of ventilation holes are evenly processed along the circumferential direction on the end cover. A round hole matching the rod section of the pull rod (1) is processed at the center of the end cover. The set screw nut (7) is threadedly connected with the rod section of the pull rod (1). The sealing sleeve (2), the pressing block (3), the gasket (6) and the end cover of the connector (5) are axially pressed through the set screw nut (7). The transition joint (10) is of a circular sleeve structure with one end closed. A pipeline joint for communicating with the outside is integrally formed at the center of the closed end of the transition joint (10). The transition joint (10) is sleeved at the end of the rod section of the pull rod (1). An intermediate sealing ring (9) is arranged between the open end face of the transition joint (10) and the small-diameter end face of the connector (5). The transition joint (10) and the connector (5) are detachably connected through the clamp (8); when the connector (5) is a short connector, the outer diameter of the sealing sleeve (2) in the non-extruded state and the inner diameter of the protective sleeve (c) are in clearance fit. At this time, the detection tool is a short detection tool, and the short detection tool is used for detecting the weld seam after welding of the protective sleeve (c) and the tube sheet (a); when the connector (5) is an extended connector, the outer diameter of the sealing sleeve (2) in the non-extruded state and the inner diameter of the heat exchange tube (b) are in clearance fit. At this time, the detection tool is an extended detection tool, and the extended detection tool is used for detecting the weld seam after welding of the protective sleeve (c) and the heat exchange tube (b).

2. The detection tool for the welded joint of the nozzle of a bayonet tube heat exchanger according to claim 1, characterized in that: When the sealing sleeve (2) is completely inserted into the inner hole of the protective sleeve (c), the length of the part of the protective sleeve (c) extending out of the tube sheet (a) away from the welding point is less than the length of the connector (5).

3. The detection tool for the welded joint of the nozzle of a bayonet tube heat exchanger according to claim 1, characterized in that: When the sealing sleeve (2) is completely inserted into the inner hole of the heat exchange tube (b), the length of the part of the heat exchange tube (b) extending out of the tube sheet (a) away from the welding point is less than the length of the connector (5).

4. The detection tool for the welded joint of the nozzle of a bayonet tube heat exchanger according to claim 2 or 3, characterized in that: A rectangular block matching the wrench clamping part is processed at the end of the rod section of the pull rod (1).

5. A detection tool for the welded joint of the bayonet tube heat exchanger nozzle according to claim 4, characterized in that: The outer diameter of the end cap of the drawbar (1) is d 1 , the outer diameter of the sealing sleeve (2) is d 2 , the inner diameter of the sealing sleeve (2) is d 3 , d 2 ≥ d 1 ≥ d 3 .

6. A detection tool for the welded joint of the bayonet tube heat exchanger nozzle according to claim 5, characterized in that: The pull rod (1), the pressing block (3) and the connecting head (5) are all made of stainless steel.

7. A detection tool for the welded joint of the bayonet tube heat exchanger nozzle according to claim 6, characterized in that: The sealing sleeve (2), the end sealing ring (4) and the middle sealing ring (9) are all made of rubber.

8. A detection tool for the welded joint of the bayonet tube heat exchanger nozzle according to claim 7, characterized in that: The gasket (6) is made of copper.

9. A detection tool for the welded joint of the bayonet tube heat exchanger nozzle according to claim 8, characterized in that: It further includes a drain screw (11). A threaded hole is machined on the outer cylindrical surface of the connecting head (5) near the tube sheet. The drain screw (11) is threadedly and hermetically installed in the threaded hole of the connecting head (5).

10. A detection method for the detection tool for the welded joint of the bayonet tube heat exchanger nozzle based on claim 9, characterized in that: The detection method for the welded joint of the bayonet tube heat exchanger nozzle is realized through the following steps. Step 1: Use a short detection tool to detect the weld seam after welding of the protection sleeve (c) and the tube sheet (a): First, insert the protection sleeve (c) into the tube sheet (a) and weld it to the protection sleeve (c) before detecting the weld seam after welding of the protection sleeve (c) and the tube sheet (a). Then, assemble the pull rod (1), the sealing sleeve (2), the pressing block (3), the gasket (6) and the locking nut (7) of the short detection tool into a component and insert it into the protection sleeve (c). At this time, the sealing sleeve (2) of the short detection tool is completely inserted into the protection sleeve (c). Furthermore, sleeved the connecting head (5) with the end sealing ring (4) on the protection sleeve (c). Use one wrench to tighten the end of the pull rod (1) to prevent the pull rod (1) from rotating. Use another wrench to tighten the locking nut (7) so that the sealing sleeve (2) expands radially under the extrusion of the pressing block (3), the gasket (6) and the connecting head (5) to achieve a tight fit with the inner hole of the protection sleeve (c). At the same time, the connecting head (5) approaches the end face of the tube sheet (a) under the action of the locking nut (7) and presses the end sealing ring (4). Even further, sleeved the transition joint (10) on the end of the pull rod (1). Place the middle sealing ring (9) between the transition joint (10) and the connecting head (5), and connect the transition joint (10) and the connecting head (5) with a clamp (8). Finally, connect the pipeline joint at the end of the transition joint (10) to the external helium leak detection pipeline or the water pressure device. After the gas or water is introduced for a period of time, tighten the drain screw (11) to conduct a leak test or a pressure test on the weld seam after welding of the protection sleeve (c) and the tube sheet (a). When the detection of the weld seam after welding of the protection sleeve (c) and the tube sheet (a) is completed, disassemble the short detection tool. Step 2: Use an extended detection tool to detect the weld seam after welding of the protection sleeve (c) and the heat exchange tube (b): First, insert the heat exchange tube (b) into the protective sleeve (c) and perform single-sided welding with the protective sleeve (c) before detecting the weld seam after welding the protective sleeve (c) and the heat exchange tube (b). Then, assemble the pull rod (1), the sealing sleeve (2), the pressing block (3), the gasket (6) and the set screw nut (7) of the extended detection tool into a component and insert it into the heat exchange tube (b). At this time, the sealing sleeve (2) of the extended detection tool is completely inserted into the heat exchange tube (b). Use one wrench to tighten the end of the pull rod (1) to prevent the pull rod (1) from rotating. Use another wrench to tighten a set screw nut (7) so that the sealing sleeve (2) expands radially under the extrusion of the pressing block (3) and the gasket (6) to achieve a tight fit with the inner hole of the heat exchange tube (b). Furthermore, sleeved the connector (5) equipped with the end sealing ring (4) on the heat exchange tube (b). Use one wrench to tighten the end of the pull rod (1) to prevent the pull rod (1) from rotating. Use another wrench to tighten another set screw nut (7) so that the connector (5) approaches the end face of the tube sheet (a) under the action of the set screw nut (7) and presses the end sealing ring (4). Even further, sleeved the adapter (10) on the end of the pull rod (1), placed the intermediate sealing ring (9) between the adapter (10) and the connector (5), and connected the adapter (10) and the connector (5) with a clamp (8). Finally, connect the pipeline connector at the end of the adapter (10) to the external helium leak detection pipeline or the water pressure device. After passing gas or water for a period of time, tighten the drain screw (11) to perform a leak test or a pressure test on the weld seam after welding the protective sleeve (c) and the heat exchange tube (b). When the detection of the weld seam after welding the protective sleeve (c) and the heat exchange tube (b) is completed, disassemble the extended detection tool. So far, the detection of the weld seam after welding the protective sleeve (c) and the tube sheet (a), as well as the weld seam after welding the protective sleeve (c) and the heat exchange tube (b) has been completed.

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