Clamp for drawing tube of nuclear power heat exchanger and using method of clamp

Abstract

The invention relates to the technical field of tube drawing of nuclear power heat exchangers, in particular to a clamp for tube drawing of a nuclear power heat exchanger and a using method of the clamp, and aims to solve the problem of connection and fixation of a tube and a force application end in the tube drawing process. The upper part of each connecting rod A is rotationally connected with the lower end of the lifting ring, and the lower part of each connecting rod A is rotationally connected with the pre-tightening top block A; a clamping hole is formed in the lower end of the hook body, and a plurality of fixing clamping grooves are fixed in the clamping hole; the pre-tightening ejector block A is rotationally connected with the hook body, the side, away from the clamping hole, of the pre-tightening ejector block A is connected with a connecting rod C through a spring, and one end of the connecting rod C is rotationally connected with the hook body; the limiting stop block is fixed on the hook body, and is positioned obliquely above the rotating connection position of the connecting rod C and the hook body; according to the scheme, the pulling-out force of the pipe and the pipe plate can be overcome, so that the expanded pipe is pulled out of the pipe plate hole.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant heat exchanger tube removal technology, specifically to a clamp for removing tubes from nuclear power plant heat exchangers and its usage method. Background Technology

[0002] In the manufacturing process of nuclear power heat exchangers, drawings and technical requirements impose strict demands on the appearance quality, welding quality, and dimensional accuracy of tube sheets and tubes. If a tube leaks or is damaged, the manufacturer must prioritize a repair solution that replaces the damaged tube. The connection between tubes and tube sheets is generally a welded and expanded joint structure, making it difficult to remove the tubes from the tube sheet holes. A repair solution could be to remove the welded joints on the tube box side using CNC drilling, but the expanded joint area has already undergone plastic deformation, and the pull-out process for each tube requires overcoming the expansion joint pull-out force of approximately ~kN / tube.

[0003] The process of removing the tube requires addressing the connection and fixation between the tube and the force-applying end to ensure more efficient tube removal using external force. The tube surface is relatively smooth and the wall thickness is relatively thin (outer diameter φ mm, wall thickness typically .~. mm). Insufficient connection strength can lead to slippage at the connection point, while excessive connection strength can cause deformation of the tube's cross-section, ultimately resulting in connection failure. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of connecting and fixing the tube to the force-applying end during the tube removal process. This invention proposes a clamp for tube removal in nuclear power heat exchangers and its usage method.

[0005] The objective of this invention is achieved as follows: a clamp for pulling tubes from a nuclear power heat exchanger, comprising a lifting ring, a hook, a limiting block, two connecting rods A, several fixing slots, and a pre-tightening top block A; The upper end of the hook body is provided with a sliding groove, the lower end of the lifting ring is slidably connected to the sliding groove, the upper part of each link A is rotatably connected to the lower end of the lifting ring, and the lower part of each link A is rotatably connected to the pre-tightening top block A. The lower end of the hook body is provided with a clamping hole, and several fixing slots are fixed in the clamping hole; The pre-tightening top block A is rotatably connected to the hook body. The side of the pre-tightening top block A away from the clamping hole is connected to the connecting rod C by a spring. One end of the connecting rod C is rotatably connected to the hook body. The limit block is fixed on the hook body and is located diagonally above the position where the connecting rod C is rotatably connected to the hook body; When not in use, the spring is in a contracted state, and the connecting rod C is set diagonally downward from one end to the other. When in use, rotate the other end of the connecting rod C upward until the connecting rod C contacts the limit block. The spring is stretched. Release the connecting rod C, and the spring contracts and pulls the connecting rod C. The connecting rod C presses against the limit block to complete the limit of the connecting rod C.

[0006] Furthermore, there are two fixed card slots.

[0007] Furthermore, several fixed slots are vertically spaced within the clamping hole.

[0008] Furthermore, a pull ring is connected to the other end of link C.

[0009] Furthermore, link C is connected to a pull ring via a pull rope.

[0010] Furthermore, it also includes a pre-tightening top block B and two connecting rods B; the pre-tightening top block B is rotatably connected to the hook body, one end of each of the two connecting rods B is rotatably connected to the pre-tightening top block B, and the other end of each of the two connecting rods B is rotatably connected to the pre-tightening top block A.

[0011] Furthermore, pre-tightening top block A and pre-tightening top block B are arranged at intervals along the length of the clamping hole.

[0012] Furthermore, both the pre-tightening top block A and the pre-tightening top block B have multiple positioning teeth on the side near the clamping hole.

[0013] The method for using clamps for removing tubes from nuclear power plant heat exchangers includes the following steps: Step 1: Using a hand chain hoist or crane as a lifting clamp, hang the lifting ring on the lifting machinery; Step 2: Start the lifting machinery and move the clamp horizontally above the tube sheet / short cylinder assembly from which the tube to be removed; Start the lifting machinery and move the clamps up and down so that the clamping hole of the hook body is aligned with a pipe to be pulled out until the pipe is inserted into the clamping hole of the hook body. Use one or two fixed slots to clamp the pipe. Step 3: Pull the pull ring upward to control the rotation of the spring and connecting rod C, which in turn controls the pre-tightening top block A to press against the pipe and the fixing groove. The pre-tightening top block A drives the pre-tightening top block B through the connecting rod B, and the pre-tightening top block B presses against the pipe and the fixing groove. Step 4: After the pull ring is pulled to its limit position, it will contact the limiting device. At this time, the spring has rotated past the axis, and the connecting rod C is locked with the limiting device, which in turn locks the pre-tightening top block A and the pre-tightening top block B to clamp the pipe in the fixed slot. Step 5: After securing the pipe with clamps, connect lifting machinery with lifting rings to assist in removing the pipe; Step 6: After the tube is removed, pull the pull ring back in the opposite direction and rotate it past the axis to release the locking state of the connecting rod C and the limiting device, and then loosen the tube between the pre-tightening top block A, the pre-tightening top block B and the fixing groove; Step 7: Repeat the above operation to remove each tube of the tube sheet / short tube assembly individually.

[0014] Beneficial effects: This invention develops a highly efficient and rapid clamping device for fixing or disassembling pipes and lifting machinery during pipe removal and repair work. This invention is applicable to repair scenarios involving partial and complete pipe replacement in nuclear power plant heat exchangers. By connecting to lifting machinery such as electric hoists or cranes, it can overcome the pull-out force of the pipes and tube sheets, thereby removing the expanded pipes from the tube sheet holes.

[0015] This invention features a compact structure, convenient assembly and disassembly, and excellent stability and efficiency. When used in conjunction with lifting machinery, it can significantly improve the efficiency of tube removal during heat exchanger repair. This fixing device replaces the original welding fixing scheme during the tube removal test phase, addressing the technical needs of partial and overall tube replacement during nuclear power heat exchanger repair, and greatly accelerating the timely completion of repair tasks. The tube removal efficiency per tube has been reduced from the original minutes / hole with worker assistance to less than [number] minutes / hole with worker assistance, nearly doubling the efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic front view of a clamp for removing tubes from a nuclear power plant heat exchanger according to the present invention; Figure 2 This is a top sectional view of a clamp for removing tubes from a nuclear power plant heat exchanger according to the present invention; Figure 3 This is a schematic diagram illustrating an application scenario for tube removal during repair. Detailed Implementation

[0017] Specific implementation method one: A clamp for pulling tubes from a nuclear power heat exchanger, which includes a lifting ring, a hook, a limiting block, two connecting rods A, several fixing slots, a pre-tightening top block A, and a connecting shaft. The upper end of the hook body is provided with a sliding groove, the lower end of the lifting ring is slidably connected to the sliding groove, the upper part of each link A is rotatably connected to the lower end of the lifting ring, and the lower part of each link A is rotatably connected to the pre-tightening top block A. The lower end of the hook body is provided with a clamping hole, and several fixing slots are fixed in the clamping hole; The pre-tightening top block A is rotatably connected to the hook body. The side of the pre-tightening top block A away from the clamping hole is connected to the connecting rod C by a spring. One end of the connecting rod C is rotatably connected to the hook body. The limit block is fixed on the hook body and is located diagonally above the position where the connecting rod C is rotatably connected to the hook body; When not in use, the spring is in a contracted state, and the connecting rod C is set diagonally downward from one end to the other. When in use, rotate the other end of the connecting rod C upward until the connecting rod C contacts the limit block. The spring is stretched. Release the connecting rod C, and the spring contracts and pulls the connecting rod C. The connecting rod C presses against the limit block to complete the limit of the connecting rod C.

[0018] In this embodiment: when not in operation, the spring is in a contracted state, and the connecting rod C is set obliquely downward from one end to the other. When in operation, the clamping hole is aligned with a tube and fitted onto its outside. The other end of the connecting rod C is rotated upward until the connecting rod C contacts the limiting block. The spring is stretched, and the pre-tightening top block A rotates on the hook body. The pre-tightening top block A and the fixing slot together clamp the tube. When the connecting rod C is released, the spring contracts and pulls the connecting rod C. The connecting rod C presses against the limiting block to complete the limiting of the connecting rod C.

[0019] Specific implementation method two: A clamp for pulling tubes from a nuclear power heat exchanger, with two fixing slots.

[0020] Other implementation methods are the same as those in Specific Implementation Method 1.

[0021] Specific implementation method three: A clamp for pulling tubes from a nuclear power heat exchanger, wherein several fixed slots are vertically spaced within the clamping hole.

[0022] Other implementation methods are the same as those in Specific Implementation Method 1.

[0023] Specific implementation method four: A clamp for pulling tubes from a nuclear power heat exchanger, wherein the other end of the connecting rod C is connected to a pull ring.

[0024] In this embodiment: the pull ring is used to pull the connecting rod C upward.

[0025] Other implementation methods are the same as those in Specific Implementation Method 1.

[0026] Specific implementation method five: A clamp for pulling tubes from a nuclear power heat exchanger, wherein the connecting rod C is connected to a pull ring via a pull rope.

[0027] In this embodiment: the connecting rod C is connected to the pull ring via a pull rope. When the pull ring is pulled upward, since the pull rope is the connecting part, the angle of the pull ring does not need to be considered and it can be pulled upward directly.

[0028] Other implementation methods are the same as those in Specific Implementation Method Four.

[0029] Specific implementation method six: A clamp for pulling tubes from a nuclear power heat exchanger, which further includes a pre-tightening top block B and two connecting rods B; the pre-tightening top block B is rotatably connected to a hook body, one end of each of the two connecting rods B is rotatably connected to the pre-tightening top block B, and the other end of each of the two connecting rods B is rotatably connected to the pre-tightening top block B.

[0030] In this embodiment: the pre-tightening top block B and the pre-tightening top block A are linked by the connecting rod B. When the pre-tightening top block A moves, the connecting rod B pulls the pre-tightening top block B to perform the same movement.

[0031] Other implementation methods are the same as those in Specific Implementation Method 1.

[0032] Specific implementation method seven: A clamp for pulling tubes from a nuclear power heat exchanger, wherein pre-tightening top block A and pre-tightening top block B are arranged at intervals along the length direction of the clamping hole.

[0033] In this embodiment: Pre-tightening top block A and pre-tightening top block B are arranged at intervals, with pre-tightening top block A corresponding to the upper fixing slot and pre-tightening top block B corresponding to the lower fixing slot.

[0034] Other implementation methods are the same as those in Specific Implementation Method 1.

[0035] Specific implementation method eight: A clamp for tube removal in nuclear power heat exchangers, wherein pre-tightening top block A and pre-tightening top block B are provided with multiple positioning teeth on the side near the clamping hole.

[0036] In this embodiment, the positioning teeth and the fixing groove work together to clamp the tube, which facilitates the application of clamping force.

[0037] Other implementation methods are the same as those in Specific Implementation Method 1.

[0038] Specific Implementation Method Nine: A method for using a clamp for removing tubes from a nuclear power plant heat exchanger, comprising the following steps: Step 1: Using a hand-operated hoist or crane as a lifting clamp, hang the lifting ring 1 on the lifting machinery; Step 2: Start the lifting machinery and move the clamp horizontally above the tube sheet / short cylinder assembly from which the tube to be removed; Start the lifting machinery and move the clamp up and down so that the clamping hole of the hook body 2 is aligned with a pipe to be pulled out until the pipe is inserted into the clamping hole of the hook body 2. Use one or two fixing slots 5 to clamp the pipe. Step 3: Pull the pull ring 7 upward to control the rotation of the spring 9 and the connecting rod C10, thereby controlling the pre-tightening top block A6 to press against the pipe and the fixing groove 5. The pre-tightening top block A6 drives the pre-tightening top block B11 through the connecting rod B4, and the pre-tightening top block B11 presses against the pipe and the fixing groove 5. Step 4: After the pull ring 7 is pulled to the limit position, it will contact the limiting device 8. At this time, the spring 9 has rotated past the axis, and the connecting rod C10 is locked with the limiting device 8, which in turn locks the pre-tightening top block A6 and the pre-tightening top block B11 to clamp the tube in the fixed slot 5. Step 5: After the clamps secure the pipe, connect the lifting machinery with the lifting ring 1 to assist in removing the pipe; Step 6: After the tube is removed, pull the pull ring 7 back in the opposite direction and rotate it past the axis to release the locking state of the connecting rod C10 and the limiting device 8, thereby loosening the tube between the pre-tightening top block A6, the pre-tightening top block B11 and the fixing groove 5; Step 7: Repeat the above operation to remove each tube of the tube sheet / short tube assembly individually.

[0039] In this embodiment: During the tube pulling process, the friction and self-locking state between the pre-tightening top block A, the pre-tightening top block B, the tube and the fixing groove may cause the tube to be crushed and deformed, but it does not affect the smooth progress of the tube pulling process; Invention principle: 1. The present invention mainly comprises a lifting ring, a hook body, connecting rod A, connecting rod B, connecting rod C, a fixing groove, a pre-tightening top block A, a pre-tightening top block B, a pull ring assembly, a limiting stop block, and multiple connecting shafts.

[0040] 2. The hook body is the frame of the entire clamping device. The upper end of the hook body has a sliding groove structure, and the lower section of the lifting ring can slide in the sliding groove.

[0041] 3. Both pre-tightening blocks A and B are connected to the hook body by a connecting shaft, and both pre-tightening blocks A and B can rotate on the hook body.

[0042] 4. The limit block and the fixing slot are fixed to the hook body as one piece.

[0043] 5. The pull ring assembly connects to the spring assembly and controls the linkage action of the connecting rod.

[0044] 6. The lifting ring is fixed to the connecting rod A with a connecting shaft, and the linkage connecting rod A, connecting rod B and pre-tightening top block move along a predetermined path.

[0045] 7. Under the linkage control, the pre-tightening top block A and the pre-tightening top block B control the relative position of the pipe to be removed and the fixed slot, and there are two working states: loosening and clamping.

[0046] 8. The limit stop restricts the rotational position of the spring assembly, and the rotation angle and elasticity of the spring control the position of the connecting rod assembly, thereby controlling the release and clamping of the preload block.

[0047] 9. Both pre-tightening top blocks A and B have a toothed anti-slip structure similar to the shape of the pipe, and the fixing slot has a patterned groove structure similar to the shape of the pipe, which can increase contact friction and help fix the pipe.

[0048] 10. During the tube removal process, the tube is subjected to pull-out force, and the friction will further increase the pressure on the pre-tightening top block A, pre-tightening top block B, tube and fixing groove, forming a self-locking state.

[0049] Work process: 1. Separate the pipe to be repaired from the pipe bundle to ensure the installation of the clamping device; 2. Insert the tube into the clamping hole of the hook body and fix it with one or more clamps; 3. Pull the pull ring upward to control the rotation of the spring and connecting rod assembly (connecting rod A, connecting rod B, connecting rod C), thereby controlling the preload block A and preload block B to press against the tube and the fixing groove; 5. After the pull ring is pulled to the limit position, the connecting rod C will contact the limiting device. At this time, the spring has rotated past the axis, and the connecting rod C is locked with the limiting device, thereby locking the pre-tightening top block, the tube and the fixing groove. 4. After the clamping device secures the pipe, a lifting ring is used to connect to the lifting machinery, which can assist in removing the pipe; 6. During the tube extraction process, the friction and self-locking state between the pre-tightening top block A, the pre-tightening top block B, the tube, and the fixing groove may cause the tube to crush and deform, but this will not affect the smooth progress of the tube extraction process. 7. After the tube is removed, pull the pull ring assembly back in the opposite direction and rotate it past the axis to release the locking state of the auxiliary pull ring assembly and the limiting device, and then loosen the pre-tightening top block, the tube and the fixing groove; 8. By repeating the above operation, the tubes of the tube bundle can be removed one by one.

Claims

1. A clamp for removing tubes from a nuclear power plant heat exchanger, characterized in that: It includes a lifting ring (1), a hook body (2), a limiting block (8), two connecting rods A (3), several fixing slots (5) and a pre-tightening top block A (6); The upper end of the hook (2) is provided with a sliding groove, the lower end of the lifting ring (1) is slidably connected to the sliding groove, the upper part of each connecting rod A (3) is rotatably connected to the lower end of the lifting ring (1), and the lower part of each connecting rod A (3) is rotatably connected to the pre-tightening top block A (6). The lower end of the hook body (2) is provided with a clamping hole, and several fixing slots (5) are fixed in the clamping hole; The pre-tightening top block A (6) is rotatably connected to the hook body (2). The side of the pre-tightening top block A (6) away from the clamping hole is connected to the connecting rod C (10) via the spring (9). One end of the connecting rod C (10) is rotatably connected to the hook body (2). The limiting block (8) is fixed on the hook body (2), and the limiting block (8) is located diagonally above the position where the connecting rod C (10) and the hook body (2) are rotatably connected; When not in use, the spring (9) is in a contracted state, and the connecting rod C (10) is set diagonally downward from one end to the other. When in use, rotate the other end of the connecting rod C (10) upward until the connecting rod C (10) contacts the limit block (8), the spring (9) is stretched, the connecting rod C (10) is released, the spring (9) contracts and pulls the connecting rod C (10), and the connecting rod C (10) presses against the limit block (8) to complete the limit of the connecting rod C (10).

2. The clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: There are two fixed card slots (5).

3. A clamp for removing tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: Several fixed slots (5) are vertically spaced within the clamping hole.

4. A clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: The other end of the connecting rod C (10) is connected to a pull ring (7).

5. A clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 4, characterized in that: Link C (10) is connected to the pull ring (7) via a pull rope.

6. A clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: It also includes a pre-tightening top block B (11) and two connecting rods B (4); the pre-tightening top block B (11) is rotatably connected to the hook body (2), one end of each of the two connecting rods B (4) is rotatably connected to the pre-tightening top block B (11), and the other end of each of the two connecting rods B (4) is rotatably connected to the pre-tightening top block A (6).

7. A clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: Pre-tightening top block A (6) and pre-tightening top block B (11) are arranged at intervals along the length of the clamping hole.

8. A clamp for pulling tubes from a nuclear power plant heat exchanger according to claim 1, characterized in that: Both the pre-tightening top block A (6) and the pre-tightening top block B (11) have multiple positioning teeth on the side near the clamping hole.

9. The method of using the clamp for pulling tubes from a nuclear power plant heat exchanger according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: Using a hand-operated hoist or crane as a lifting clamp, hang the lifting ring (1) on the lifting machinery; Step 2: Start the lifting machinery and move the clamp horizontally above the tube sheet / short cylinder assembly from which the tube to be removed; Start the lifting machinery and move the clamp up and down so that the clamping hole of the hook body (2) is aligned with a pipe to be pulled out until the pipe is inserted into the clamping hole of the hook body (2). Use one or two fixed slots (5) to clamp the pipe. Step 3: Pull the pull ring (7) upward to control the rotation of the spring (9) and the connecting rod C (10), thereby controlling the pre-tightening top block A (6) to press against the pipe and the fixed groove (5). The pre-tightening top block A (6) drives the pre-tightening top block B (11) through the connecting rod B (4), and the pre-tightening top block B (11) presses against the pipe and the fixed groove (5). Step 4: After the pull ring (7) is pulled to the limit position, it will contact the limiting device (8). At this time, the spring (9) has rotated past the axis, and the connecting rod C (10) is locked with the limiting device (8), thereby locking the pre-tightening top block A (6) and the pre-tightening top block B (11) to clamp the pipe in the fixed slot (5); Step 5: After the clamps fix the pipe, use the lifting ring (1) to connect the lifting machinery to help remove the pipe; Step 6: After the tube is removed, pull the pull ring (7) back in the opposite direction and rotate it past the axis to release the locking state of the connecting rod C (10) and the limiting device (8), and then loosen the tube between the pre-tightening top block A (6), the pre-tightening top block B (11) and the fixing groove (5); Step 7: Repeat the above operation to remove each tube of the tube sheet / short tube assembly one by one.

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