Special pneumatic claw for automatic positioning equipment of heat transfer tube of heat exchanger

Abstract

The utility model discloses a special pneumatic claw for automatic positioning equipment for a heat transfer tube of a heat exchanger, which relates to the technical field of nondestructive testing of heat exchangers in the electric power industry and comprises a moving substrate, and a cushion block is mounted above the moving substrate; a lower piston structure of the piston pull rod is mounted in the central cylinder body, and forms an air cylinder structure with the lower end cover and the upper end cover, and the expansion head acts in the pipe hole; the utility model relates to a fixing device required by tube plate crawling positioning equipment applied to eddy current testing equipment, the device is called as a pneumatic claw, and the pneumatic claw can enable the tube plate crawling positioning equipment to tightly grasp a tube hole and freely crawl or position on a tube plate. The pneumatic claw can realize the expansion action, the contraction action, the action of inserting the expansion head into the pipe hole and the action of pulling the expansion head out of the pipe hole in the pipe hole, can be applied to grasping and positioning of various heat transfer pipe holes, and provides technical support for realizing automatic detection of eddy current detection of more heat transfer pipes of heat exchangers.

Description

Technical Field

[0001] This utility model relates to the field of non-destructive testing technology for heat exchangers in the power industry, and in particular to a special pneumatic gripper for automatic positioning equipment of heat exchanger heat transfer tubes. Background Technology

[0002] In industries such as nuclear power plants, thermal power plants, and chemical manufacturing, heat transfer tubes are the core components of heat exchangers, and their performance directly affects the heat transfer efficiency. Eddy current testing can detect problems such as corrosion and fouling in heat transfer tubes. By promptly repairing or replacing damaged heat transfer tubes, their cleanliness and integrity can be maintained, improving the heat transfer efficiency of the heat exchanger. For example, heat transfer tubes with significantly thinned walls can affect heat conduction. Detecting and repairing such defects through eddy current testing can restore the equipment to normal performance. During production, heat exchanger failures often lead to production line shutdowns. Regular eddy current testing can identify potential problems with heat transfer tubes in a timely manner, allowing for proactive repair or replacement and avoiding prolonged downtime caused by sudden failures. For example, performing eddy current testing during shutdown maintenance or equipment cut-out for repairs ensures that the equipment is in good condition for the next operation, guaranteeing production continuity.

[0003] Eddy current testing can effectively detect defects such as corrosion, cracks, and wall thinning in heat exchange tubes. For example, for heat exchange tubes made of non-ferromagnetic materials, conventional eddy current testing technology can detect defects such as localized pitting and grooved corrosion on the tube wall; for heat exchange tubes made of ferromagnetic materials, far-field eddy current testing technology can also detect similar defects. Timely detection of these defects can prevent them from expanding further, prevent accidents such as leaks and ruptures in the heat exchange tubes, and ensure the safe operation of the equipment.

[0004] Currently, most heat exchanger heat transfer tube eddy current testing is done manually by pushing and pulling the probe. Only in radiation environments such as nuclear power plants will automated eddy current testing equipment be used to replace manual pushing and pulling and tube hole positioning.

[0005] Therefore, this utility model proposes a special pneumatic gripper for an automatic positioning device for heat exchanger heat transfer tubes. Utility Model Content

[0006] The purpose of this utility model is to solve the defects existing in the prior art and to propose a special pneumatic gripper for automatic positioning equipment of heat exchanger heat transfer tubes.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A special pneumatic gripper for automatic positioning of heat exchanger heat transfer tubes includes a moving base plate with a pad mounted on top of the moving base plate; it also includes a piston rod, the lower piston structure of which is installed inside the central cylinder and together with the lower end cover and the upper end cover to form a cylinder structure in which the expansion head moves within the tube hole; the lower part of the piston rod is also equipped with a first guide ring, a first oil seal ring, a second guide ring, a sealing gasket, a first sealing ring, a third guide ring, a second sealing ring, and a third sealing ring; a spring is installed in the middle of the piston rod;

[0009] The upper part of the piston rod is detachably equipped with an expansion head, a stop block, an expansion head, and a front guide block; the two expansion heads are separated by a stop block.

[0010] The front guide block and the upper part of the piston rod are connected and fixed by a limiting pin;

[0011] It also includes two piston rods. The lower piston structure of the two piston rods is installed inside the central cylinder body and together with the lower end cover and the upper end cover, it forms a cylinder structure for the expansion head to insert into or pull out of the pipe hole. The lower ends of the two piston rods are also equipped with a fourth sealing ring, a fourth guide ring, and a fifth sealing ring.

[0012] The upper part of the piston rod is mounted on the motion base plate, and the upper part of the piston rod is sealed and guided to the central cylinder by the second oil seal ring and the fifth guide ring.

[0013] Four guide shafts are mounted on the motion base plate, and linear bearings are fitted onto the guide shafts. The linear bearings are installed in the fixing holes of the central cylinder.

[0014] Furthermore, the pad, which serves as a limiting plate in contact with the heat exchanger tube sheet, is made of non-metallic material.

[0015] Furthermore, the expansion head is made of a flexible non-metallic material.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] 1. The contact material between the air gripper and the heat transfer tube is non-metallic to avoid wear on the inner wall of the heat transfer tube caused by contact between the metal material and the inner wall of the heat transfer tube.

[0018] 2. The structural design of the upper part of the pneumatic gripper makes it easier to replace the expansion head and maintain it, greatly reducing the technical requirements and economic costs of maintenance.

[0019] 3. The upper part of the pneumatic gripper is designed with two expansion heads, which makes the gripper more aligned after completing the tightening action, and the friction formed by the contact of the two surfaces is more reliable.

[0020] 4. The contact material between the air gripper and the heat transfer tube is non-metallic, while the heat transfer tube is usually metallic. Compared with air grippers made of other metallic materials, to generate the same frictional force, the non-metallic air gripper in this design requires a smaller positive contact pressure. As a result, the air gripper exerts less pressure on the inner wall of the heat transfer tube, protecting the heat transfer tube and preventing it from deforming due to excessive contact pressure.

[0021] 5. The expansion head insertion and extraction actions of the air gripper are designed with four linear guide shafts, which allows the air gripper to withstand greater torque. The air gripper designed in this way can be used for both vertical and horizontal heat transfer tube sheets.

[0022] 6. A spring is installed in the middle of the piston rod. When the air supply to the cylinder is cut off, the spring can pull the piston rod back, maintaining the expansion head in an expanded state. This structural design ensures that the pneumatic gripper has appropriate gripping force in the event of an air shortage, preventing the equipment from falling.

[0023] 7. The large circular structure of the pad provides the pneumatic gripper with a larger support area when subjected to radial overturning torque, thus enabling it to withstand larger overturning torques in any direction.

[0024] 8. The pads are made of non-metallic materials, so that the contact between the air gripper and the heat transfer tube sheet is non-metallic, avoiding the wear of the heat transfer tube sheet caused by contact between metallic materials and the heat transfer tube sheet.

[0025] In summary, this utility model provides a fixing device for a tube sheet crawling and positioning device used in eddy current testing equipment. This device is called a pneumatic gripper. The pneumatic gripper enables the tube sheet crawling and positioning device to grip the tube hole and crawl or position freely on the tube sheet. The pneumatic gripper of this utility model can realize the expansion head tightening action, expansion head contraction action, expansion head insertion action, and expansion head extraction action within the tube hole. It can be applied to gripping and positioning tube holes of various heat transfer tubes, providing technical support for the automated detection of eddy current testing of heat transfer tubes in more heat exchangers. Attached Figure Description

[0026] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0027] Figure 1 This is a front view of the present invention;

[0028] Figure 2 This is a front internal sectional view of the present invention;

[0029] Figure 3 This is a left-side internal sectional view of the present invention;

[0030] Figure 4This is a schematic diagram showing the positions of the first pneumatic connector, the second pneumatic connector, the third pneumatic connector, the fourth pneumatic connector, and the fifth pneumatic connector;

[0031] Figure 5 This is a schematic diagram showing the locations of the first, second, third, fourth, and fifth air inlets;

[0032] Figure 6 This is a schematic diagram of the present invention when the expansion head is inserted into the tube hole;

[0033] Figure 7 This is a schematic diagram of the present invention when the expansion head is pulled out of the tube hole.

[0034] In the diagram: 1. Front guide block; 2. Expansion head; 3. Stop block; 4. Upper end cover; 5. Pad block; 6. Protective cover; 7. Central cylinder body; 8. Lower end cover; 9. Limiting pin; 10. Piston rod; 11. First guide ring; 12. First oil seal ring; 13. Second guide ring; 14. Sealing gasket; 15. Spring; 16. First sealing ring; 17. Third guide ring; 18. Second sealing ring; 19. Third sealing ring; 20. Linear bearing; 21. Guide shaft; 22. Piston rod; 23. Fourth sealing ring; 24. Fourth guide ring; 25. Fifth sealing ring; 26. Motion base plate; 27. Second oil seal ring; 28. Fifth guide ring;

[0035] A1 First pneumatic connector; a1 First air port; A2 Second pneumatic connector; a2 Second air port; B1 Third pneumatic connector; b1 Third air port; B2 Fourth pneumatic connector; b2 Fourth air port; B3 Fifth pneumatic connector; b3 Fifth air port. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model;

[0037] Reference Figure 1-7 This utility model mainly includes a cylinder structure for the expansion head to move inside the tube hole and a cylinder structure for the expansion head to be inserted into or pulled out of the tube hole as a whole.

[0038] Specifically, it includes a motion base plate 26, and a pad 5 is installed on top of the motion base plate 26;

[0039] It also includes a piston rod 10. The lower piston structure of the piston rod 10 is installed inside the central cylinder 7, forming a cylinder structure with the lower end cover 8 and the upper end cover 4, so that the expansion head can move in the pipe hole. The lower part of the piston rod 10 is also equipped with a first guide ring 11, a first oil seal ring 12, a second guide ring 13, a sealing gasket 14, a spring 15, a first sealing ring 16, a third guide ring 17, a second sealing ring 18, and a third sealing ring 19. A spring 15 is installed in the middle of the piston rod 10.

[0040] The upper part of the piston rod 10 is detachably equipped with an expansion head 2, a stop block 3, an expansion head 2, and a front guide block 1; the two expansion heads 2 are separated by the stop block 3.

[0041] The pad 5, which is a limiting plate that contacts the heat exchanger tube sheet, is made of non-metallic material. It serves as a positioning reference for the pneumatic gripper's action and also protects the tube sheet from wear.

[0042] The various sealing rings and guide rings form a cylinder sealing and guiding structure;

[0043] The front guide block 1 and the upper part of the piston rod 10 are connected and fixed by the limiting pin 9;

[0044] The expansion head 2 is made of a flexible non-metallic material.

[0045] After removing the limiting pin 9, the front guide block 1 can be taken out, making it easy to replace the expansion head 2. A spring 15 is installed in the middle of the piston rod 10. When the cylinder is cut off, the spring 15 can pull the piston rod 10 back to keep the expansion head 2 in an expanded state.

[0046] It also includes two piston rods 22. The lower piston structure of the two piston rods 22 is installed inside the central cylinder body 7, and together with the lower end cover 8 and the upper end cover 4, it forms a cylinder structure for the expansion head to insert or pull out of the pipe hole. The lower ends of the two piston rods 22 are also equipped with a fourth sealing ring 23, a fourth guide ring 24, and a fifth sealing ring 25. Each sealing ring and the guide ring form a cylinder sealing and guiding structure.

[0047] The upper part of the piston rod 22 is mounted on the motion base plate 26, and the upper part of the piston rod 22 is sealed and guided with the central cylinder 7 by the second oil seal ring 27 and the fifth guide ring 28.

[0048] Four guide shafts 21 are mounted on the upper part of the motion base plate 26. The guide shafts 21 are fitted with linear bearings 20, which are installed in the fixing holes of the central cylinder 7.

[0049] With the cooperation of four guide shafts 21, the two piston rods 22 can control the lifting and lowering of the motion base plate 26 through the action of the cylinder.

[0050] A first pneumatic connector A1 and a third pneumatic connector B1 are provided on one side of the top of the central cylinder 7; the first pneumatic connector A1 is connected to the first air port a1, and the third pneumatic connector B1 is connected to the third air port b1.

[0051] The bottom of the central cylinder 7 is provided with a second pneumatic connector A2, a fourth pneumatic connector B2, and a fifth pneumatic connector B3; the second pneumatic connector A2 is connected to the second air port a2, the fourth pneumatic connector B2 is connected to the fourth air port b2, and the fifth pneumatic connector B3 is connected to the fifth air port b3.

[0052] The working principle of this utility model is as follows:

[0053] The expansion head tightening action of the air gripper in the tube hole: The expansion head 2 is completely inserted into the heat transfer tube hole of the heat exchanger, the pad 5 is in contact with the heat transfer tube plate, compressed air is introduced into the first air port a1, the piston rod 10 is pulled down and back, the two expansion heads 2 are deformed due to compression and expand on the inner wall of the heat transfer tube hole, the expanded expansion head 2 forms two annular surfaces in contact. As the air pressure of the compressed air introduced into the first air port a1 increases, the positive pressure formed between the expansion head 2 and the inner wall of the heat transfer tube hole increases, thereby increasing the static friction force, and completing the expansion head tightening action.

[0054] The expansion head retraction action of the air gripper in the tube hole: The expansion head 2 is completely inserted into the heat transfer tube hole of the heat exchanger, and the pad 5 is in contact with the heat transfer tube plate. When compressed air is introduced into the second air port a2, the piston rod 10 is pushed upward, and the compressive force of the two expansion heads 2 is released. Since the expansion head 2 is an elastic non-metallic material, it can restore its original shape after deformation. Therefore, the expansion head 2 rebounds to a size smaller than the inner diameter of the heat transfer tube hole, completing the expansion head retraction action.

[0055] The action of inserting the expansion head into the tube hole: The expansion head 2 is completely inserted into the heat transfer tube hole of the heat exchanger, and the pad 5 is in contact with the heat transfer tube plate. When compressed air is introduced into the third air port b1, the piston rod 22 is pulled back downwards, the central cylinder 7 moves upwards, and drives the upper end cover 4 to move upwards. Its upper surface is in contact with the lower surface of the moving base plate 26, and at the same time, it drives the expansion head 2 to be inserted into the heat transfer tube hole, thus completing the action of inserting the expansion head into the tube hole.

[0056] The expansion head is pulled out of the tube hole by the air gripper: The expansion head 2 is fully inserted into the heat transfer tube hole of the heat exchanger, and the pad 5 is in contact with the heat transfer tube plate. When compressed air is introduced into the fourth air port b2 and the fifth air port b3 at the same time, the piston rod 22 is pushed upward, the central cylinder 7 moves downward, and the upper end cover 4 moves downward, its upper surface separates from the lower surface of the moving base plate 26, and at the same time, the expansion head 2 is pulled out from the heat transfer tube hole, completing the expansion head pulling out of the tube hole action.

[0057] In this embodiment, the contact material between the air gripper and the heat transfer tube is a non-metallic material to avoid wear on the inner wall of the heat transfer tube caused by contact between a metallic material and the inner wall of the heat transfer tube.

[0058] In this embodiment, the structural design of the upper part of the pneumatic gripper makes it easier to replace the expansion head 2 and maintain it, greatly reducing the technical requirements and economic costs of maintenance.

[0059] In this embodiment, two expansion heads 2 are designed on the upper part of the pneumatic gripper, so that the pneumatic gripper has better centering after completing the tensioning action, and the friction force formed by the contact of the two surfaces is more reliable.

[0060] In this embodiment, the contact material between the gripper and the heat transfer tube is a non-metallic material, while the heat transfer tube is usually made of metal. Compared with grippers made of other metallic materials, to generate the same frictional force, the non-metallic gripper designed in this way requires a smaller positive contact pressure. As a result, the pressure of the gripper on the inner wall of the heat transfer tube is smaller, protecting the heat transfer tube and preventing it from deforming due to excessive contact pressure.

[0061] In this embodiment, the expansion head insertion and extraction actions of the air gripper are designed with four linear guide shafts, which allows the air gripper to withstand greater torque. The air gripper designed in this way can be applied to both vertically and horizontally laid heat transfer tube sheets.

[0062] In this embodiment, a spring 15 is installed in the middle of the piston rod 10. When the air supply to the cylinder is cut off, the spring 15 can pull the piston rod 10 back, maintaining the expansion head 2 in an expanded state. This structural design ensures that the pneumatic gripper has an appropriate gripping force when the air supply is cut off, protecting the equipment from falling.

[0063] In this embodiment, the large-sized circular structure design of the pad 5 gives the pneumatic gripper a larger support area when it is subjected to radial flipping torque, thus enabling it to withstand larger flipping torque in any direction.

[0064] In this embodiment, the pad 5 is made of non-metallic material, so that the contact between the air gripper and the heat transfer tube sheet is non-metallic, thus avoiding the wear of the heat transfer tube sheet caused by the contact between the metal material and the heat transfer tube sheet.

Claims

1. A special pneumatic gripper for heat exchanger heat transfer tube automatic positioning equipment, comprising a moving base plate (26), a cushion block (5) is installed above the moving base plate (26); characterized in that, The lower piston structure of the piston rod (10) is mounted inside the central cylinder (7) and the lower end cover (8) and the upper end cover (4) to form a cylinder structure with the expansion head acting in the pipe hole, and the lower part of the piston rod (10) is further provided with a first guide ring (11), a first oil seal ring (12), a second guide ring (13), a sealing gasket (14), a first sealing ring (16), a third guide ring (17), a second sealing ring (18), and a third sealing ring (19); the middle part of the piston rod (10) is provided with a spring (15); The upper part of the piston rod (10) is detachably provided with an expansion head (2), a stop block (3), an expansion head (2), and a front end guide block (1) in sequence; the two expansion heads (2) are separated by the stop block (3); The front end guide block (1) and the upper part of the piston rod (10) are connected and fixed by a limiting pin (9); The lower piston structure of the two piston rods (22) is mounted inside the central cylinder (7) and the lower end cover (8) and the upper end cover (4) to form a cylinder structure with the expansion head acting in the pipe hole, and the lower end of the two piston rods (22) is further provided with a fourth sealing ring (23), a fourth guide ring (24), and a fifth sealing ring (25); The upper part of the piston rod (22) is mounted on a moving base plate (26), and the upper part of the piston rod (22) and the central cylinder (7) are sealed and guided by a second oil seal ring (27) and a fifth guide ring (28); Four guide shafts (21) are mounted on the moving base plate (26), the guide shafts (21) are sleeved with linear bearings (20), and the linear bearings (20) are mounted in the fixed holes of the central cylinder (7).

2. The automatic positioning equipment for heat exchanger heat transfer tube special gas claws according to claim 1, characterized in that, The gasket (5) is used as a limiting plate in contact with the heat exchanger tube plate and is made of non-metallic material.

3. The automatic positioning equipment for heat exchanger heat transfer tube special gas claws according to claim 2, characterized in that, The expansion head (2) is made of elastic non-metallic material.

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