Pressure test device for welded joint of tube plate and heat exchange tube

Abstract

The utility model belongs to the technical field of detection equipment manufacturing, and particularly relates to a pressure test device for a welded joint of a tube plate and a heat exchange tube, which comprises a main gas path, a branch gas path, a pressing sleeve and a stud, the branch gas path is arranged on the main gas path, one end, far away from the main gas path, of the branch gas path is hermetically communicated with one end of the pressing sleeve, and an internal thread is arranged at one end, far away from the main gas path, of the pressing sleeve; an external thread matched with the internal thread is arranged at one end of the stud, a top disc is arranged at the other end of the stud, an airtight assembly is arranged on the end face, back to the branch air path, of the pressing sleeve, an airtight assembly is also arranged on the face, facing the stud, of the top disc, and airflow in the pressing sleeve can flow out from the end, in threaded connection with the stud, of the pressing sleeve; according to the method, effective detection can be effectively carried out after each inner hole welding heat exchanger tube plate and heat exchange tube connection welding seam is completed, leakage of the welding seam is found in time, and the leaked welding seam can be reworked in time; and the waste of time and labor cost caused by huge repair due to weld joint leakage in the final pressure test of the whole heat exchanger is avoided.

Description

Technical Field

[0001] The present application belongs to the technical field of testing equipment manufacturing, and specifically relates to a pressure testing device for welding joints between tube sheets and heat exchange tubes. Background Art

[0002] Internally welded heat exchangers are primarily used in applications where pipe joints must bear heavy loads, minimize stress concentrations, and withstand fatigue. They are core equipment in the petroleum, chemical, and nuclear industries. A manufacturing risk in heat exchangers is that visual inspection of the weld seam after welding the heat exchanger tubes to the tubesheet alone cannot verify weld quality. Surface inspection of these welds can also be performed using the PT method commonly used in pressure vessel inspections. However, due to the 60° or 90° angle between the tubesheet holes, at least one-third or one-quarter of the welds remain undetected after formation, leading to missed inspections. Therefore, leak testing is required to ensure the quality of the welds between the tubesheet and the heat exchanger tubes. This means that each weld must be tested after welding. Currently, shell-side hydrostatic testing is used. Consequently, if leaks are detected during shell-side hydrostatic testing, all welds must be recut before re-welding. This labor-intensive repair process is why designers prioritize weld quality during manufacturing. Summary of the Invention

[0003] Aiming at the difficult requirements for detecting weld seams of tube sheets of internal hole welded heat exchangers, this application provides a quick and simple pressure testing device to solve the problem of how to conduct a test on each weld seam after welding.

[0004] In order to achieve the above objectives, the technical solution adopted in this application is:

[0005] A pressure testing device for the welded joint between a tube sheet and a heat exchange tube comprises a main gas path, a branch gas path, a press sleeve and a stud. The main gas path is provided with a branch gas path, and the branch gas path is sealed and connected to one end of the press sleeve at one end away from the main gas path. The press sleeve is provided with an internal thread at one end away from the main gas path, and an external thread matching the internal thread at one end of the stud is provided, and a top plate is provided at the other end of the stud. An airtight component is provided on the end face of the press sleeve facing away from the branch gas path, and an airtight component is also provided on the surface of the top plate facing the stud. When the stud is threadedly matched with the press sleeve, the airflow in the press sleeve can flow out from the end connected to the stud thread.

[0006] Preferably, the outer diameter of the external thread of the stud is smaller than the depth of the internal thread.

[0007] Preferably, a through hole is provided on the stud, one end of the through hole is on the stud away from the end surface of the top plate, and the other end of the through hole is on the circumferential surface of the stud and located between the external thread and the top plate.

[0008] Preferably, the airtight component is a sealing ring.

[0009] Preferably, the projection of the inner cross section of the pressing sleeve on the end surface of the pressing sleeve is located within the sealing ring on the end surface of the pressing sleeve, and the projection of the external thread on the top plate is located within the sealing ring on the top plate.

[0010] Preferably, the sealing ring located on the end surface of the pressing sleeve is coaxial with the pressing sleeve.

[0011] Preferably, the sealing ring on the top plate is coaxial with the stud.

[0012] Preferably, the sealing ring is provided on the coaxial sleeve at one end of the pressing sleeve away from the air path, and the distance from the side of the sealing ring on the pressing sleeve facing away from the air path to the plane where the end face of the pressing sleeve facing the air path is located is greater than the length of the pressing sleeve.

[0013] Preferably, one or more branch gas paths are provided on the main gas path.

[0014] Preferably, a pressure gauge is provided on the total gas line.

[0015] Compared with the prior art, this application has the following beneficial effects:

[0016] The present application can effectively detect the connection welds between the tube sheet and the heat exchange tube of each inner hole welded heat exchanger after completion, and promptly detect weld leaks so that the leaking welds can be reworked in a timely manner, thus avoiding the huge waste of time and manpower costs caused by rework when weld leaks are discovered during the final pressure test of the entire heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the present application when testing the tube sheet and heat exchange tubes;

[0018] Figure 2 for Figure 1 Exploded diagram;

[0019] Figure 3 Schematic diagram of the structure of setting through holes on the stud.

[0020] Among them, 1. Main gas line; 2. Branch gas line; 3. Press sleeve; 4. Stud; 5. Top plate; 6. Through hole; 7. Sealing ring; 8. Pressure gauge; 9. Mounting nozzle; 10. Tube sheet; 11. Heat exchange tube. DETAILED DESCRIPTION

[0021] like Figure 1-3As shown, a pressure testing device for the welded joint of a tube sheet and a heat exchange tube comprises a main gas path 1, a branch gas path 2, a press sleeve 3 and a stud 4. The main gas path 1 is provided with a branch gas path 2, and the branch gas path 2 is sealed and connected to one end of the press sleeve 3 at one end away from the main gas path 1. The press sleeve 3 is provided with an internal thread at one end away from the main gas path 1, and an external thread matching the internal thread is provided at one end of the stud 4. A top plate 5 is provided at the other end of the stud 4. An airtight component is provided on the end face of the press sleeve 3 facing away from the branch gas path 2, and an airtight component is also provided on the surface of the top plate 5 facing the stud 4. When the stud 4 is threadedly matched with the press sleeve 3, the airflow in the press sleeve 3 can flow out from the end threadedly connected to the stud 4.

[0022] In this embodiment, after the heat exchange tube 11 is welded to the tube sheet 10, the end of the pressing sleeve 3 facing away from the gas distribution path 2 is pressed against the side of the tube sheet 10 facing away from the heat exchange tube 11, and the pressing sleeve 3 is made coaxial with the heat exchange tube 11. Thereafter, the end of the stud 4 facing away from the top plate 5 is inserted from the end of the heat exchange tube 11 facing away from the tube sheet 10 and penetrates into the pressing sleeve 3. Then, the stud 4 is twisted so that the external thread on the stud 4 cooperates with the internal thread on the pressing sleeve 3 until the airtight component on the top plate 5 is tightly fitted with one end of the heat exchange tube, and the airtight component on the pressing sleeve 3 is tightly fitted with the other end of the heat exchange tube. Afterwards, a bubble generator is applied to the outer surface of the weld between the tube sheet 10 and the heat exchange tube 11. Gas is then pumped in (introduced) from the main gas line 1 via an air pump. The gas passes through the main gas line 1 to the branch gas line 2 and then into the compression sleeve 3. Since the airflow in the compression sleeve 3 can flow out from the end threaded with the stud 4, the gas in the compression sleeve 3 flows into the heat exchange tube under pressure. While the gas is continuously pressed into the main gas line 1, the presence of the airtight assembly prevents the gas in the heat exchange tube 11 from flowing out of the end. Therefore, if there is a leak in the weld, the bubbles generated can be used to detect unqualified weld quality. The length of the stud 4 is tailored to the length of the heat exchange tube 11 being tested.

[0023] There are two classic ways to enable the airflow in the pressing sleeve 3 to flow out from the end where the pressing sleeve 3 is threadedly connected to the stud 4.

[0024] Method 1: The outer diameter of the external thread of the stud 4 is smaller than the depth of the internal thread. This arrangement prevents the stud 4 and the compression sleeve 3 from axially falling off, and also ensures that the gas in the compression sleeve 3 can enter the heat exchange tube 11 during testing. In other words, the gas will flow into the heat exchange tube along the gap between the external and internal threads under pressure.

[0025] In the first embodiment, the stud 4 is provided with a through hole 6, one end of which is located on the stud 4 away from the end surface of the top plate 5, and the other end of which is located on the circumferential surface of the stud 4 and between the external thread and the top plate 5. With this arrangement, the airflow (gas) in the compression sleeve 3 flows into the heat exchange tube 11 through the through hole 6.

[0026] Specifically, the airtight component is a sealing ring 7 .

[0027] Specifically, the projection of the inner cross section of the pressing sleeve 3 on the end surface of the pressing sleeve 3 is located inside the sealing ring 7 on the end surface of the pressing sleeve 3 , and the projection of the external thread on the top plate 5 is located inside the sealing ring 7 on the top plate 5 .

[0028] As a preferred embodiment, the sealing ring 7 on the end surface of the pressing sleeve 3 is coaxial with the pressing sleeve 3. This arrangement makes the entire device more beautiful.

[0029] As a preferred embodiment, the sealing ring 7 on the top plate 5 is coaxial with the stud 4. This allows the sealing ring 7 to be fully utilized.

[0030] Preferably, the top plate 5 is a circular plate.

[0031] As a preferred embodiment, the sealing ring 7 is coaxially sleeved on one end of the press sleeve 3 away from the gas branch 2, and the distance from the side of the sealing ring 7 on the press sleeve 3 facing away from the gas branch 2 to the plane where the end face of the press sleeve 3 facing the gas branch 2 is located is greater than the length of the press sleeve 3. This arrangement facilitates the installation of the sealing ring 7 and simultaneously allows the sealing ring 7 to protrude from the end face of the press sleeve 3 facing away from the gas branch 2, thereby ensuring airtightness between the press sleeve 3 and the heat exchange tube 11 when the press sleeve 3 abuts against the tube sheet 10.

[0032] Preferably, a mounting nozzle 9 is coaxially and sealedly provided on one end of the pressing sleeve 3 away from the gas branch 2. The outer diameter of the mounting nozzle 9 is smaller than the outer diameter of the pressing sleeve 3, and the outer diameter of the mounting nozzle 9 is larger than the inner diameter of the gas branch 2. The mounting nozzle 9 is a hollow structure with both ends open, which facilitates the installation of the sealing ring 7 on the pressing sleeve 3. At the same time, when in use, the sealing ring 7 on the pressing sleeve 3 is squeezed between the end face of the pressing sleeve 3 and the tube sheet 10, thereby ensuring the airtightness between the pressing sleeve 3 and the heat exchange tube 11.

[0033] As a preferred embodiment, one or more branch gas paths 2 are provided on the main gas path 1. This arrangement allows the welds between one tube sheet 10 and a heat exchange tube 11 to be inspected at a time, or the welds between several tube sheets 10 and heat exchange tubes 11 to be inspected at a time.

[0034] As a preferred embodiment, a pressure gauge 8 is provided on the main gas line 1 to detect the air pressure on the main gas line 1 to avoid excessive or insufficient pressure.

Claims

1. A pressure test device for welding joints between tube sheets and heat exchange tubes, characterized in that: The invention comprises a main gas path (1), a branch gas path (2), a pressing sleeve (3), and a stud (4), wherein the main gas path (1) is provided with a branch gas path (2), and one end of the branch gas path (2) away from the main gas path (1) is sealed and connected to one end of the pressing sleeve (3), and the end of the pressing sleeve (3) away from the main gas path (1) is provided with an internal thread, and one end of the stud (4) is provided with an external thread matched with the internal thread, and the other end of the stud (4) is provided with a top plate (5), and an airtight component is provided on the end face of the pressing sleeve (3) facing away from the branch gas path (2), and an airtight component is also provided on the side of the top plate (5) facing the stud (4), and when the stud (4) is threadedly matched with the pressing sleeve (3), the air flow in the pressing sleeve (3) can flow out from the end threadedly connected with the stud (4).

2. A pressure testing device for welded joints between tube sheets and heat exchange tubes according to claim 1, characterized in that: The outer diameter of the external thread of the stud (4) is smaller than the depth of the internal thread.

3. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 1, characterized in that: A through hole (6) is provided on the stud (4), one end of the through hole (6) is on the stud (4) away from the end surface of the top plate (5), and the other end of the through hole (6) is on the circumferential surface of the stud (4) and located between the external thread and the top plate (5).

4. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 1, characterized in that: The airtight component is a sealing ring (7).

5. A pressure testing device for welding joints between tube sheets and heat exchange tubes according to claim 4, characterized in that: The projection of the inner cross section of the pressing sleeve (3) on the end face of the pressing sleeve (3) is located inside the sealing ring (7) on the end face of the pressing sleeve (3), and the projection of the external thread on the top plate (5) is located inside the sealing ring (7) on the top plate (5).

6. A pressure testing device for welded joints between tube sheets and heat exchange tubes according to claim 5, characterized in that: The sealing ring (7) located on the end surface of the pressing sleeve (3) is coaxial with the pressing sleeve (3).

7. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 5, characterized in that: The sealing ring (7) located on the top plate (5) is coaxial with the stud (4).

8. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 4, characterized in that: The sealing ring (7) is provided on the coaxial sleeve at one end of the pressing sleeve (3) away from the air distribution path (2), and the distance from the side of the sealing ring (7) on the pressing sleeve (3) facing away from the air distribution path (2) to the plane where the end face of the pressing sleeve (3) facing the air distribution path (2) is located is greater than the length of the pressing sleeve (3).

9. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 1, characterized in that: One or more branch gas paths (2) are provided on the main gas path (1).

10. The pressure testing device for the welded joint between a tube sheet and a heat exchange tube according to claim 1, characterized in that: A pressure gauge (8) is provided on the main gas line (1).

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