Tube pulling device for heat exchange tubes of double-tube-sheet heat exchanger and using method of tube pulling device

By using hollow bolts and pull plates in the dual-tube plate heat exchanger combined with electric heating components and mechanical pulling, the breakage problem caused by expansion and mechanical locking of the heat exchange tube during the pipe diversion process is solved, the success rate and operating efficiency of the pipe are improved, and the integrity of the inner pipe plate is ensured.

CN119617949APending Publication Date: 2025-03-14JIANGSU DONGFANG RUIJI ENERGY EQUIP CO LTD
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Patent Information

Application Number
CN202411916251.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-12-24
Publication Date
2025-03-14

AI Technical Summary

Technical Problem

In the double-tube plate heat exchanger, the heat exchange tube is prone to breaking due to residual expansion force and mechanical locking formed by the groove structure of the inner tube plate during the pipe diversion process, and the groove position is difficult to pull out, which increases the difficulty of operation and difficulty in subsequent repair.

Method used

A double-tube plate heat exchanger heat exchange pipe diversion device is adopted. Through the combination of hollow bolts and pulling plates, combined with electric heating components and mechanical pulling, the expansion and connection stress between the heat exchange pipe and the inner pipe plate is gradually reduced, and the resistance to the pipe is reduced.

Benefits of technology

It effectively solves the problem of heat exchange pipe disassembly, improves the success rate and operating efficiency of pipe replacement, avoids damage to the inner wall of the inner tube plate hole, and ensures the structural integrity and subsequent use performance of the inner tube plate.

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Abstract

The invention discloses a double-tube-plate heat exchanger heat exchange tube pulling device and a using method thereof.The double-tube-plate heat exchanger heat exchange tube pulling device comprises a pulling plate, the pulling plate is arranged on a heat exchange tube and located on the outer side of an outer tube plate through a hollow bolt, and a plurality of top-pull bolts are symmetrically arranged between the pulling plate and the outer tube plate with the hollow bolt as the center; the binding post is concentrically connected in the heat exchange tube in a penetrating mode through the hollow bolt, one end of the binding post extends out of the hollow bolt and is externally connected with a welding machine power source, and the electric heating assembly is arranged at the position, corresponding to the expanded connection position of the heat exchange tube and the inner tube plate, of the binding post. The problem that the heat exchange tube is pulled and broken due to overlarge expansion force is thoroughly solved, the success rate and the operation efficiency of tube replacement are improved, the expansion force between the heat exchange tube and the inner tube plate is eliminated, meanwhile, mechanical damage to the inner wall of the inner tube plate hole is avoided, and the structural integrity and the follow-up use performance of the inner tube plate are ensured.
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Description

Technical Field

[0001] The invention belongs to the technical field of heat exchange tube pulling of a heat exchanger, and in particular relates to a heat exchange tube pulling device of a double tube sheet heat exchanger and a use method thereof. Background Art

[0002] In the double tube sheet heat exchanger, the inner tube sheet and the heat exchange tube adopt an expansion structure, and the outer tube sheet and the heat exchange tube adopt a welding structure. During the manufacturing or use process, due to various reasons, some heat exchange tubes may be damaged and leak, and it is necessary to remove the tubes. During the removal process, the following problems are faced: 1. Friction resistance caused by residual expansion force: After the heat exchange tubes and the inner tube sheet are expanded, there is a large residual expansion force between the heat exchange tubes and the inner tube sheet. During the tube pulling process, this expansion force will cause extremely high friction resistance, increasing the difficulty of tube pulling; 2. Mechanical locking formed by the groove structure of the inner tube sheet: The inner tube sheet is designed with grooves. After expansion, the metal of the heat exchange tube is squeezed into the grooves to form a boss structure (such as Figure 2 As shown in the figure), this structure generates significant mechanical resistance when the tube is pulled out, further increasing the difficulty of pulling out the tube; 3. The heat exchange tube is broken and the groove position is difficult to pull out: Under the combined influence of the above factors, if force is directly applied to pull the tube out, the heat exchange tube may break in the middle, and the tube in the groove cannot be pulled out smoothly, making subsequent pipe plugging or repair operations extremely difficult.

[0003] At present, the following two methods are usually used to deal with the problems caused by heat exchange tube leakage, but both have obvious defects: 1. Method for plugging heat exchange tubes: Loss of heat exchange area of ​​the heat exchange tube reduces the heat exchange efficiency of the heat exchanger; The operation is difficult due to space limitations, and the reliability is poor after the heat exchange tubes are blocked, which makes it easy for leakage to occur again; 2. Mechanical removal method: Use a drill or milling cutter to remove the expanded part of the heat exchange tube. The inner wall of the tube hole of the tube sheet is easily damaged during the processing. Once the inner wall is damaged, the sealing performance of the subsequent expansion joint is difficult to ensure, and there is a risk of leakage; To this end, we propose a heat exchange tube pulling device for a double-tube sheet heat exchanger and a method for using the same. Summary of the invention

[0004] The object of the present invention is to provide a heat exchange tube pulling device for a double tube sheet heat exchanger and a method for using the same, so as to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a heat exchange tube pulling device for a double tube sheet heat exchanger, comprising: A pull plate, which is arranged on the heat exchange tube and located outside the outer tube plate through hollow bolts; A plurality of top pull bolts are provided, and the plurality of top pull bolts are symmetrically arranged between the pull plate and the outer tube plate with the hollow bolt as the center; A terminal post, wherein the terminal post is concentrically connected to the heat exchange tube through the hollow bolt, and one end of the terminal post extends out of the hollow bolt and is externally connected to a welding machine power source; An electric heating component is arranged on the terminal post at a position corresponding to the expansion joint of the heat exchange tube and the inner tube plate.

[0006] Preferably, the hollow bolt is an insulating bolt made of insulating material.

[0007] Preferably, a through hole for the terminal to pass through is opened in the middle of the hollow bolt.

[0008] Preferably, an internal thread is provided in the heat exchange tube at a position corresponding to the outer tube sheet, and the internal thread is threadably connected to the hollow bolt.

[0009] Preferably, a bolt hole matching the hollow bolt is provided in the middle of the pull plate.

[0010] Preferably, the terminal is a conductive terminal made of conductive material.

[0011] Preferably, the electric heating component comprises a resistance wire and insulating ceramics; The resistance wire is evenly wound around the terminal at the expansion joint position corresponding to the heat exchange tube and the inner tube plate, and the insulating ceramic is arranged outside the resistance wire.

[0012] A method for using a heat exchange tube pulling device for a double tube sheet heat exchanger comprises the following steps: A: The inner end of the outer tube sheet of the heat exchange tube to be pulled out is tapped to form an internal thread that matches the hollow bolt, and then the electric heating component is inserted into the heat exchange tube through the terminal to the expansion position corresponding to the inner tube sheet; B: Then screw the hollow bolt into the bolt hole in the middle of the pull plate, then pass the end of the terminal extending out of the heat exchange tube through the through hole in the center of the hollow bolt, then connect the hollow bolt with the internal thread in the heat exchange tube, then screw several symmetrically distributed top pull bolts on the pull plate, so that the pull plate and the outer tube sheet are abutted through the top pull bolts; C: Connect the terminal to the welding machine power supply, adjust the current of the welding machine power supply, cut off the heat at the expansion joint of the heat exchange tube and the inner tube sheet through the electric heating component, and slowly turn the top pull bolt to slowly increase the distance between the pull plate and the outer tube sheet, and then pull the heat exchange tube outward. Under the action of the pulling force, the heating part of the heat exchange tube gradually becomes thinner, so that the expansion joint of the heat exchange tube and the inner tube sheet begins to separate; D: After the heating stops, wait for the heat exchange tube to cool down. At this time, the expansion stress of the heat exchange tube is completely released. Then tighten the top pull bolts and completely pull the heat exchange tube out from the inner tube plate.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Effectively solve the problem of pipe breakage: The present invention significantly reduces the tube pulling resistance by combining local heating with mechanical pulling, completely solves the problem of heat exchange tube breakage caused by excessive expansion force, and improves the success rate and operation efficiency of tube replacement. 2. Avoid damage to the inner wall of the inner tube plate hole: The present invention eliminates the expansion stress between the heat exchange tube and the inner tube sheet by accurately controlling the heating area and the heating temperature, and avoids mechanical damage to the inner wall of the inner tube sheet hole, thereby ensuring the structural integrity and subsequent performance of the inner tube sheet. 3. Accurate heating range to avoid tube sheet quality impact The present invention only performs local rapid heating on the heat exchange tubes, the temperature of the inner tube sheet increases very little, and has no adverse effect on the quality and performance of the inner tube sheet; 4. Use welding machine power supply, which is economical, efficient and safe: Use the existing welding machine power supply as the heating power supply, without the need to purchase additional equipment, and make full use of the characteristics of the welding machine's high current and low voltage (below 30 volts). The heating power is large and the operation is safe, which reduces the cost of use and improves practicality; 5. Does not affect the secondary expansion effect: After the heat exchange tube is pulled out, the residual stress in the expansion joint between the heat exchange tube and the inner tube sheet has been completely released, and the inner wall of the inner tube sheet hole remains intact, ensuring the secondary expansion effect and sealing performance of the heat exchange tube, and completely solving the technical problems in the process of replacing the heat exchange tube of the double tube sheet heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional structural schematic diagram of the present invention; Figure 2 Schematic diagram of the expansion structure of the heat exchange tube and the inner tube sheet.

[0015] In the figure: 1. Pull plate; 2. Hollow bolt; 3. Heat exchange tube; 4. Outer tube sheet; 5. Top pull bolt; 6. Terminal; 7. Electric heating assembly; 8. Inner tube sheet. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 The heat exchange tube pulling device of the double tube sheet heat exchanger provided by the present invention comprises: A pull plate 1 is arranged on the heat exchange tube 3 and outside the outer tube sheet 4 through a hollow bolt 2. A bolt hole matching the hollow bolt 2 is provided in the middle of the pull plate 1. An internal thread is provided at a position corresponding to the outer tube sheet 4 in the heat exchange tube 3. The internal thread is threadedly connected with the hollow bolt 2. A plurality of top tension bolts 5 are provided, and the plurality of top tension bolts 5 are symmetrically arranged between the tension plate 1 and the outer tube plate 4 with the hollow bolt 2 as the center; The terminal 6 is a conductive terminal made of conductive material. The terminal 6 is concentrically connected to the heat exchange tube 3 through the hollow bolt 2. A through hole for the terminal 6 to pass through is opened in the middle of the hollow bolt 2, and one end of the terminal 6 extends out of the hollow bolt 2 and is externally connected to a welding machine power supply. The electric heating component 7 is arranged on the terminal 6 at the expansion position corresponding to the heat exchange tube 3 and the inner tube plate 8.

[0018] In this embodiment, the hollow bolt 2 is an insulating bolt made of insulating material, and the electric heating component 7 includes a resistance wire and insulating ceramics; the resistance wire is evenly wound on the terminal 6 at the expansion position corresponding to the heat exchange tube 3 and the inner tube plate 8, and the insulating ceramic is arranged on the outside of the resistance wire to play an insulating role between the terminal 6, the electric heating component 7 and the heat exchange tube 3, and at the same time the terminal 6 is concentrically arranged in the heat exchange tube 3.

[0019] The method for using the heat exchange tube pulling device of the double tube sheet heat exchanger provided by the present invention comprises the following steps: A: The inner end of the outer tube sheet 4 of the heat exchange tube 3 to be pulled out is tapped to form an internal thread that matches the hollow bolt 2, and then the electric heating component 7 is inserted into the heat exchange tube 3 through the terminal 6 to the expansion position corresponding to the inner tube sheet 8; B: Then screw the hollow bolt 2 into the bolt hole in the middle of the pull plate 1, then extend the end of the terminal 6 outside the heat exchange tube 3 through the through hole in the center of the hollow bolt 2, and then thread the hollow bolt 2 with the internal thread in the heat exchange tube 3, and then screw a number of symmetrically distributed top pull bolts 5 on the pull plate 1, so that the pull plate 1 and the outer tube plate 4 are abutted through the top pull bolts 5; C: Connect the terminal 6 to the welding power supply, adjust the current of the welding power supply, cut off the heat at the expansion joint of the heat exchange tube 3 and the inner tube sheet 8 through the electric heating component 7, and slowly turn the top pull bolt 5 to slowly increase the distance between the pull plate 1 and the outer tube sheet 4, and then pull the heat exchange tube 3 outward. Under the action of the pulling force, the heating part of the heat exchange tube 3 gradually becomes thinner, so that the expansion joint of the heat exchange tube 3 and the inner tube sheet 8 begins to separate; D: After the heating stops, wait for the heat exchange tube 3 to cool down. At this time, the expansion stress of the heat exchange tube 3 is completely released, and then tighten the top tension bolt 5 to completely pull the heat exchange tube 3 out of the inner tube plate 8.

[0020] In the present invention, the expansion joint between the heat exchange tube 3 and the inner tube sheet 8 is heated by the electric heating assembly 7, which has the following effects: 1. Elimination of expansion stress: When the electric heating assembly 7 heats the heat exchange tube 3, the wall of the heat exchange tube expands due to the heat. Since the temperature rise of the inner tube sheet 8 is small, it is limited by the thermal stress, resulting in plastic deformation of the heat exchange tube 3. After cooling, the heat exchange tube shrinks freely, the diameter becomes smaller, and a gap is formed between the inner tube sheet 8, eliminating the expansion stress; 2. Utilization of plastic deformation: The yield strength of the material in the heated area of ​​the heat exchange tube 3 decreases, the elongation increases, and it becomes easier to break away from the groove structure of the inner tube sheet after being thinned by the tensile force; When external force is applied to pull, the heat exchange tube at the groove can be smoothly separated from the notch, and the tube pulling process is unobstructed; 3. Complete reduction of resistance: After the heat exchange tube is heated and cooled, there is no stress in the expansion joint, and there is an obvious gap between the heat exchange tube and the inner tube sheet hole. The tube pulling resistance is greatly reduced, thus avoiding the tube breakage phenomenon.

[0021] The present invention adopts a combination of heating and mechanical extubation, which has the following effects: 1. Effectively solve the problem of pipe breakage: The present invention significantly reduces the tube pulling resistance by combining local heating with mechanical pulling, completely solves the problem of heat exchange tube breakage caused by excessive expansion force, and improves the success rate and operation efficiency of tube replacement. 2. Avoid damage to the inner wall of the inner tube plate hole: The present invention eliminates the expansion stress between the heat exchange tube and the inner tube sheet by accurately controlling the heating area and the heating temperature, and avoids mechanical damage to the inner wall of the inner tube sheet hole, thereby ensuring the structural integrity and subsequent performance of the inner tube sheet. 3. Accurate heating range to avoid tube sheet quality impact The present invention only performs local rapid heating on the heat exchange tubes, the temperature of the inner tube sheet increases very little, and has no adverse effect on the quality and performance of the inner tube sheet; 4. Use welding machine power supply, which is economical, efficient and safe: Use the existing welding machine power supply as the heating power supply, without the need to purchase additional equipment, and make full use of the characteristics of the welding machine's high current and low voltage (below 30 volts). The heating power is large and the operation is safe, which reduces the cost of use and improves practicality; 5. Does not affect the secondary expansion effect: After the heat exchange tube is pulled out, the residual stress in the expansion joint between the heat exchange tube and the inner tube sheet has been completely released, and the inner wall of the inner tube sheet hole remains intact, ensuring the secondary expansion effect and sealing performance of the heat exchange tube, and completely solving the technical problems in the process of replacing the heat exchange tube of the double tube sheet heat exchanger.

[0022] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat exchange tube pulling device for a double tube sheet heat exchanger, characterized in that: include, A pull plate (1), the pull plate (1) being arranged on the heat exchange tube (3) and located outside the outer tube plate (4) via a hollow bolt (2); A plurality of top-tension bolts (5) are provided, and the plurality of top-tension bolts (5) are symmetrically arranged between the pull plate (1) and the outer tube plate (4) with the hollow bolt (2) as the center; A terminal (6), the terminal (6) being concentrically connected to the heat exchange tube (3) through the hollow bolt (2), and one end of the terminal (6) extending out of the hollow bolt (2) and being externally connected to a welding machine power source; An electric heating component (7), the electric heating component (7) being arranged on the terminal post (6) at a location corresponding to an expansion joint between the heat exchange tube (3) and the inner tube sheet (8).

2. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: The hollow bolt (2) is an insulating bolt made of insulating material.

3. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: A through hole for the connecting post (6) to pass through is provided in the middle of the hollow bolt (2).

4. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: An internal thread is provided in the heat exchange tube (3) at a position corresponding to the outer tube plate (4), and the internal thread is threadedly connected to the hollow bolt (2).

5. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: A bolt hole matching the hollow bolt (2) is provided in the middle of the pull plate (1).

6. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: The terminal (6) is a conductive terminal made of conductive material.

7. The heat exchange tube pulling device of a double tube sheet heat exchanger according to claim 1, characterized in that: The electric heating component (7) comprises a resistance wire and insulating ceramics; The resistance wire is evenly wound around the terminal (6) at the expansion joint position corresponding to the heat exchange tube (3) and the inner tube plate (8), and the insulating ceramic is arranged outside the resistance wire.

8. The method for using the heat exchange tube pulling device of a double tube sheet heat exchanger according to any one of claims 1 to 7, characterized in that: The steps include: A: An internal thread matching the hollow bolt (2) is formed by tapping the inner end of the outer tube sheet (4) corresponding to the heat exchange tube (3) to be pulled out, and then the electric heating component (7) is inserted into the heat exchange tube (3) through the terminal (6) at the expansion joint position corresponding to the inner tube sheet (8); B: Then screw the hollow bolt (2) into the bolt hole in the middle of the pull plate (1), then pass the end of the terminal (6) extending outside the heat exchange tube (3) through the through hole in the center of the hollow bolt (2), then thread the hollow bolt (2) and the internal thread in the heat exchange tube (3), then screw a plurality of symmetrically distributed top pull bolts (5) on the pull plate (1) so that the pull plate (1) and the outer tube plate (4) are in contact with each other through the top pull bolts (5); C: Connect the terminal (6) to the welding machine power supply, adjust the current of the welding machine power supply, cut off the heat at the expansion joint of the heat exchange tube (3) and the inner tube plate (8) through the electric heating component (7), and slowly turn the top tension bolt (5) to slowly increase the distance between the tension plate (1) and the outer tube plate (4), thereby pulling the heat exchange tube (3) outward. Under the action of the tension, the heated part of the heat exchange tube (3) gradually becomes thinner, so that the expansion joint of the heat exchange tube (3) and the inner tube plate (8) begins to separate; D: After the heating stops, wait for the heat exchange tube (3) to cool down. At this time, the expansion stress of the heat exchange tube (3) is completely released. Then, tighten the top tension bolt (5) and completely pull the heat exchange tube (3) out of the inner tube plate (8).