A method for removing heat exchanger tubes due to abnormal expansion joints in a heat exchanger tube sheet.

Abstract

This invention belongs to the field of heat exchanger manufacturing and discloses a method for pulling out heat exchanger tubes with abnormal tube sheet expansion joints. The aim is to solve the problem of pulling out heat exchanger tubes that have bulged due to abnormal hydraulic expansion joint positions in the tube sheet. To achieve this objective, the bulging area of ​​the heat exchanger tube and the tube sheet transition area are longitudinally divided. During the tube pulling process, the bulge contracts as it passes through the tube sheet, thus smoothly pulling out the bulging heat exchanger tube. The technical solution provided by this invention solves the problem of pulling out bulging heat exchanger tubes. This method is also applicable to pulling out similar tubes that are wider in the middle and narrower at both ends. This method can pull out the entire bulging heat exchanger tube without damaging other connected components, leaving no residue. It avoids the problem of scratching or damaging the tube sheet due to forceful tube pulling, and even affecting the subsequent normal operation of the heat exchanger.

Description

Technical Field

[0001] This invention belongs to the field of heat exchanger manufacturing, and specifically relates to a method for pulling out heat exchanger tubes when the tube sheet of a heat exchanger is abnormally expanded. Background Technology

[0002] During the manufacturing process of heat exchangers, hydraulic expansion is required to connect the tube sheet and heat exchange tubes. Hydraulic expansion is also one of the main connection methods between heat exchange tubes and tube sheets. (See...) Figure 1 Due to the design structure of the hydraulic tube expander and the operator's mistake in using the wrong expander, the hydraulic expansion area can easily exceed the tube sheet thickness, extending beyond the tube sheet. (See...) Figure 2 Because heat exchange tubes located outside the tube sheet lack effective support from the tube sheet, they are highly susceptible to bulging. Since bulging heat exchange tubes need to be pulled out and replaced, due to the heat exchanger structure, bulging tubes must be pulled out through the tube sheet or baffles. However, the outer diameter of the bulging heat exchange tube is much larger than the tube sheet, making it almost impossible to pull it out by external force, which is extremely difficult. If the heat exchange tube is pulled out by force in this situation, it is usually broken, but the bulging portion remains inside the heat exchanger, affecting its subsequent normal operation. This method also scratches and damages the tube sheet, causing significant harm. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for pulling out heat exchanger tubes when the expansion joint of the heat exchanger tube sheet is abnormal. The purpose is to solve the problem of pulling out heat exchanger tubes after they bulge due to abnormal hydraulic expansion joint position of the heat exchanger tube sheet.

[0004] To achieve the objective of this invention, the technical solution adopted is as follows:

[0005] The present invention provides a method for pulling out heat exchanger tubes with abnormal expansion joints in a heat exchanger tube sheet. This method involves dividing the heat exchanger tube at the bulge along the longitudinal direction so that it can contract when passing through the tube sheet, thereby successfully pulling out the bulging heat exchanger tube.

[0006] The procedure for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet includes the following steps:

[0007] (1) Determine the location, diameter, and shape of the bulge;

[0008] (2) Cut the heat exchange tube that needs to be pulled out by internal cutting at a distance of 10mm to 20mm from the bulge position;

[0009] (3) Use an electric rotary file to divide the high point of the bulge area into 3 to 6 segments along the longitudinal direction from the inside to the outside, and divide the tube sheet transition area into 3 to 6 segments along the longitudinal direction from the inside to the outside;

[0010] (4) Rotate the conical threaded tube puller into the heat exchange tube and pull it out.

[0011] In step (1), the location, diameter, and shape of the bulge are determined by endoscopy.

[0012] In step (2), the cut is preferably made 15mm away from the bulge; the internal cutting method is to use an internal cutting knife or a special tube cutter for heat exchange tubes.

[0013] In step (3), the high point of the bulge area is preferably divided into 4 segments along the longitudinal direction from the inside to the outside; the tube sheet transition area is preferably divided into 4 segments along the longitudinal direction from the inside to the outside; the diameter of the grinding head of the electric rotary file is less than or equal to 5mm; the length of the segment along the longitudinal direction from the inside to the outside at the high point of the bulge area is preferably 5mm to 10mm; the length of the segment along the longitudinal direction from the inside to the outside at the tube sheet transition area is preferably 5mm to 10mm.

[0014] Among them, the preferred method for removing the tube in step (4) is a hydraulic tube puller.

[0015] The above technical solution has the following beneficial effects:

[0016] 1. Solve the problem of pulling out heat exchange tubes that are "bulging", or similar problems such as the tube being larger in the middle and smaller at both ends.

[0017] 2. This tube removal method will not damage other connected components, and the heat exchange tube in the "bulge" state can be completely pulled out without any residue. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a normal hydraulic expansion joint;

[0019] Figure 2 This is a schematic diagram of an abnormal hydraulic expansion joint.

[0020] Figure 3 A schematic diagram of cutting off a heat exchange tube with abnormal expansion joint provided by the present invention;

[0021] Figure 4 A schematic diagram showing the division of the area around the bulge;

[0022] Figure 5 This is a schematic diagram showing the segmentation of the tube sheet transition area. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Example 1

[0025] A method for removing heat exchanger tubes with abnormal expansion joints in a heat exchanger tube sheet:

[0026] (1) Location Confirmation: Confirm the diameter and shape of the bulge using an endoscope and measuring tools, mark the location, and formulate a removal plan; according to the measurement, in this embodiment, the bulge diameter is the nominal diameter of the heat exchange tube + 10mm, and the bulge shape is shown in [reference to previous section]. Figure 2 The area shown is the "bulge area".

[0027] (2) Cut off: such as Figure 3 As shown, use a heat exchanger tube cutter to cut the heat exchanger tube to be pulled out along the circumference at a distance of 10mm from the bulge.

[0028] (3) Bump segmentation: In this embodiment, the selected electric rotary file head has a diameter of 5mm, and then it is longitudinally divided into 4 segments from the inside to the outside from the highest point of the bump area, with a length of 5mm, such as... Figure 4 As shown;

[0029] (4) Transition Zone Segmentation: In this embodiment, the selected electric rotary file head has a diameter of 5mm and is used to divide the tube sheet transition area longitudinally from the inside out into 4 segments, each 5mm in length, such as... Figure 5 As shown;

[0030] (5) Tube removal: Rotate the conical threaded tube remover into the heat exchange tube.

[0031] The bulging heat exchange tube is slowly pulled out using a hydraulic tube puller. In this embodiment, the operating parameters of the hydraulic cupping device are: tube pulling range: φ10~φ50mm; clamping cylinder stroke: 235mm; maximum pulling force: 500kN; pulling stroke: 200mm; maximum pulling speed: 5mm / s.

[0032] Example 2

[0033] A method for removing heat exchanger tubes with abnormal expansion joints in a heat exchanger tube sheet:

[0034] (1) Location Confirmation: Confirm the diameter and shape of the bulge using an endoscope and measuring tools, mark the location, and formulate a removal plan; according to the measurement, in this embodiment, the bulge diameter is the nominal diameter of the heat exchange tube + 10mm, and the bulge shape is shown in [reference to previous section]. Figure 2 The area shown is the "bulge area".

[0035] (2) Cutting off: Use a heat exchange tube cutter to cut the heat exchange tube to be pulled out along the circumference at a distance of 20mm from the bulge.

[0036] (3) Bump segmentation: In this embodiment, the diameter of the selected electric rotary file is 4mm, and then it is segmented longitudinally from the inside to the outside from the high point of the bump area into 3 segments with a length of 10mm.

[0037] (4) Transition zone division: In this embodiment, the selected electric rotary file head has a diameter of 4mm and is divided into 3 segments with a length of 10mm along the longitudinal direction from the inside to the outside in the tube sheet transition area.

[0038] (5) Pulling out the tube: Rotate the conical threaded tube puller into the heat exchange tube, and slowly pull out the bulging heat exchange tube with the hydraulic tube puller. In this embodiment, the working parameters of the hydraulic cupping device are: tube pulling range: φ10~φ50mm; clamping cylinder stroke: 235mm; maximum pulling force: 500kN; pulling stroke: 200mm; maximum pulling speed: 5mm / s.

[0039] Example 3

[0040] A method for removing heat exchanger tubes with abnormal expansion joints in a heat exchanger tube sheet:

[0041] (1) Location Confirmation: Confirm the diameter and shape of the bulge using an endoscope and measuring tools, mark its location, and formulate a removal plan; the bulge diameter is measured to be the nominal diameter of the heat exchange tube + 10mm, and the bulge shape is shown in the figure. Figure 2 The area shown is the "bulge area".

[0042] (2) Cutting off: Use a heat exchange tube cutter to cut the heat exchange tube to be pulled out along the circumference at a distance of 15mm from the bulge.

[0043] (3) Bump segmentation: In this embodiment, the diameter of the selected electric rotary file head is 3mm, and then it is divided into 6 segments with a length of 8mm from the inside to the outside along the longitudinal direction from the high point of the bump area.

[0044] (4) Transition zone division: In this embodiment, the selected electric rotary file head has a diameter of 3mm and is divided into 6 segments with a length of 8mm in the tube sheet transition zone from the inside to the outside along the longitudinal direction.

[0045] (5) Pulling out the tube: Rotate the conical threaded tube puller into the heat exchange tube, and slowly pull out the bulging heat exchange tube with the hydraulic tube puller. In this embodiment, the working parameters of the hydraulic cupping device are: tube pulling range: φ10~φ50mm; clamping cylinder stroke: 235mm; maximum pulling force: 500kN; pulling stroke: 200mm; maximum pulling speed: 5mm / s.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for removing heat exchanger tubes due to abnormal expansion joints in a heat exchanger tube sheet, characterized in that, Including the following steps: (1) Determine the location, diameter, and shape of the bulge; (2) Cut the heat exchange tube that needs to be pulled out using an internal cutting method at a distance of 10mm to 20mm from the bulge location; (3) Use an electric rotary file to divide the high point of the bulge area into 3 to 6 segments along the longitudinal direction from the inside to the outside, and divide the tube sheet transition area into 3 to 6 segments along the longitudinal direction from the inside to the outside; (4) Rotate the conical threaded tube puller into the heat exchange tube and pull it out.

2. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: Step (1) involves using an endoscope to determine the location, diameter, and shape of the bulge.

3. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: Step (2) Cut at a distance of 15mm from the bulge.

4. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: The internal cutting method described in step (2) is to cut the tube using an internal cutting knife or a special tube cutter for heat exchange tubes.

5. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: In step (3), the high point of the bulge area is divided into 4 segments along the longitudinal direction from the inside to the outside.

6. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: In step (3), the tube sheet transition zone is divided into four segments along the longitudinal direction from the inside to the outside.

7. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: The diameter of the grinding head of the electric rotary file in step (3) is less than or equal to 5 mm.

8. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: In step (3), the high point of the bulge area is divided into segments from the inside to the outside along the longitudinal direction, with a length of 5mm to 10mm.

9. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: In step (3), the tube sheet transition zone is divided into segments with a length of 5mm to 10mm from the inside to the outside along the longitudinal direction.

10. The method for removing heat exchanger tubes with abnormal expansion joints in the heat exchanger tube sheet according to claim 1, characterized in that: Step (4) involves using a hydraulic tube puller to remove the tube.

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