A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant.

Abstract

This utility model relates to a special tool for replacing secondary pins of medium-voltage circuit breakers in nuclear power plants. It includes a handle, a connecting tube, and a toothed support tube. One end of the connecting tube is connected to the handle, and the other end is connected to the toothed support tube. The toothed support tube is used for replacing secondary pins. The toothed support tube consists of a sleeve and a syringe. One end of the sleeve has a syringe, and the other end is connected to the connecting tube. The outer diameter φ1 of the syringe ranges from 3 to 5 mm, and the inner diameter φ2 ranges from 2.5 to 4.5 mm. Compared with existing technologies, the syringe of this special tool has various inner diameter specifications, covering common secondary pin diameters and ensuring accurate adaptation to different pins. This special tool is simple to operate, has few parts, is quick to disassemble, highly reliable, and does not damage the retaining spring, thus improving the efficiency of nuclear power plant equipment maintenance, reducing operation and maintenance costs, and ensuring the safe and stable operation of the nuclear power plant.

Description

Technical Field

[0001] This utility model relates to the field of nuclear power plant equipment maintenance technology, and in particular to a special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant. Background Technology

[0002] In the overhaul and maintenance of the 10kV medium-voltage circuit breakers at the AP1000 nuclear power plant, replacing the pins of the secondary plug-in in the control circuit is a critical task. However, the currently used techniques have many serious shortcomings.

[0003] On the one hand, existing maintenance tools have extremely poor versatility. Due to significant differences in key parameters such as diameter and length of secondary plug-in pins produced by different manufacturers, most commonly available maintenance tools are designed only for a specific specification. This forces nuclear power plants to stock a large number of various tools, resulting in high tool management costs and requiring maintenance personnel to spend a significant amount of time identifying and selecting the appropriate tools during each maintenance operation, greatly impacting maintenance efficiency. For example, to cope with several common pin specifications, nuclear power plants have dozens of different models of daily maintenance tools piled up in their warehouses, and staff spend several hours selecting tools before each maintenance operation.

[0004] On the other hand, a more challenging issue is that traditional routine maintenance tools are not specifically designed for the unique fixing structure and spring clip characteristics of the secondary connector pins in the AP1000 nuclear power plant. During actual disassembly, the inability to precisely control the direction and force of the applied force easily damages the connector pin fixing spring clips. Once the spring clips are damaged, the stability of the connector pin fixing will be greatly reduced. This can lead to poor contact of the secondary connector, affecting the normal operation of the circuit breaker control circuit, and in severe cases, even causing power outages, posing a direct threat to the safe and stable power supply of the nuclear power plant. Statistics show that in previous maintenance operations, the use of ordinary tools to disassemble the connector pins resulted in a high probability of spring clip damage, and frequent replacement of spring clips and related spare parts further increased maintenance costs.

[0005] Furthermore, the lack of specialized tools makes pin replacement extremely complex and time-consuming. Typically, removing a single secondary plug requires three people working together and takes about a day. This lengthy maintenance cycle not only severely disrupts the normal operation and maintenance schedule of nuclear power plants, but also incurs enormous labor costs based on the daily rate for nuclear power workers. Moreover, the currently common practice of replacing entire circuit breakers is extremely wasteful. The cost of a single pin is only about 1,000 yuan, while replacing an entire circuit breaker costs hundreds of thousands of yuan. The replacement of numerous unnecessary parts undoubtedly consumes a significant amount of valuable financial resources from nuclear power plants.

[0006] In conclusion, it is urgent to develop a dedicated tool for replacing the secondary pins of the control circuit of the 10kV medium-voltage circuit breaker in the AP1000 nuclear power plant. Utility Model Content

[0007] The purpose of this invention is to solve the problems of difficult pin replacement, easy damage to the retaining spring, and low efficiency in existing technologies, thereby providing a special tool for replacing secondary pins of medium-voltage circuit breakers in nuclear power plants. The syringe of this special tool has various inner diameters to cover common secondary pin diameters, ensuring accurate fit to different pins. This special tool is simple to operate, has few parts, is quick to disassemble, highly reliable, and does not damage the retaining spring, thus improving the efficiency of nuclear power plant equipment maintenance, reducing operation and maintenance costs, and ensuring the safe and stable operation of nuclear power plants.

[0008] The objective of this utility model can be achieved through the following technical solutions:

[0009] A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant includes a handle, a connecting tube, and a toothed support tube. One end of the connecting tube is connected to the handle, and the other end of the connecting tube is connected to the toothed support tube. The toothed support tube is used to replace the secondary pins.

[0010] The toothed tube consists of a sleeve and a syringe. One end of the sleeve is fitted with the syringe, and the other end is connected to a connecting tube. The outer diameter φ1 of the syringe ranges from 3 to 5 mm, and the inner diameter φ2 of the syringe ranges from 2.5 to 4.5 mm.

[0011] The toothed tube has a multi-size adaptability function to accommodate secondary insertion pins of different diameters.

[0012] In one embodiment of this utility model, both the upper and lower ends of the connecting pipe are provided with lead screws, and the upper and lower ends of the connecting pipe are respectively connected to the handle and the toothed tube through a lead screw.

[0013] In one embodiment of this utility model, the outer surface of the lead screw is provided with threads.

[0014] In one embodiment of this utility model, the handle and the sleeve are each provided with a screw hole on the side adjacent to the lead screw, and the lead screw is threadedly connected to the screw hole.

[0015] As a preferred technical solution, the length h4 of the screw hole is 6mm and the diameter M4 of the screw hole is 5mm.

[0016] As a preferred technical solution, the length h5 of the lead screw is 6mm and the diameter M5 of the lead screw is 5mm.

[0017] In one embodiment of this utility model, the length h1 of the handle is 55-65mm, preferably 60mm.

[0018] The handle adopts an ergonomic arc design with a diameter φ3 of 10mm.

[0019] The handle surface is covered with a non-slip texture for the operator to grip and apply force. This design fully considers the operator's grip comfort and ease of application during actual operation, and can effectively improve the accuracy and stability of operation.

[0020] In one embodiment of this utility model, the length h2 of the connecting pipe is 45-55mm, preferably 50mm.

[0021] In one embodiment of this utility model, the total length h3 of the toothed tube is 33-47 mm, preferably 40 mm.

[0022] In one embodiment of this utility model, the length h6 of the sleeve is 8-12mm, preferably 10mm;

[0023] The diameter M6 of the sleeve is 8-12 mm, preferably 10 mm.

[0024] In one embodiment of this utility model, the length h7 of the syringe is 25-35mm, preferably 30mm.

[0025] In one embodiment of this utility model, the handle and the connecting tube are made of steel.

[0026] As a preferred technical solution, the handle is made of high-strength engineering special steel, which has corrosion resistance to extend its service life.

[0027] As a preferred technical solution, the connecting tube is made of corrosion-resistant special steel. This steel has high strength and high toughness, and can withstand long-term corrosion in different environments, ensuring the long-term reliable use of the tool in the special environment of a nuclear power plant. At the same time, it can effectively transmit and rationally distribute the external force applied by the operator, and work closely with the handle and the support tube to form a stable mechanical support system, ensuring a smooth and stable pin removal process.

[0028] As a preferred technical solution, the inner surface of the needle tube of the toothed tube is subjected to surface strengthening treatment to form a wear-resistant layer with high hardness and low friction coefficient, so as to extend the service life of the tool.

[0029] As a preferred technical solution, the outer diameter φ1 of the syringe is 5mm and the inner diameter φ2 of the syringe is 4.5mm. This size is based on the precise adaptation of the secondary insertion pin size of the AP1000 nuclear power plant. While ensuring a tight fit with the insertion pin, an appropriate operating gap is reserved so that the disassembly force is evenly applied to the insertion pin surface, avoiding damage to the retaining spring.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The special tool for replacing the secondary pins of medium-voltage circuit breakers in nuclear power plants provided by this utility model can be quickly operated by a single person, with a low rate of damage to the retaining springs, greatly improving maintenance efficiency and reducing operation and maintenance costs. It has significant economic and social benefits and is widely applicable to the maintenance of 10kV medium-voltage circuit breakers in AP1000 nuclear power plants.

[0032] 2. The toothed tube design of this utility model features multi-size adaptability. The inner diameter can be adjusted by changing the toothed tube to accommodate secondary insertion pins of different diameters. The needle tube has at least three different inner diameters, covering common secondary insertion pin diameter specifications and ensuring precise adaptation to different pins. This unique multi-size adaptability design allows the tool to be compatible with the specifications of secondary insertion pins produced by most manufacturers on the market. Nuclear power plants no longer need to stock large quantities of complex specialized tools; they only need a small number of the general-purpose specialized tools of this utility model to handle various maintenance scenarios. Tool management costs are drastically reduced, inventory space is effectively freed up, and great convenience is brought to nuclear power plant operation and maintenance work.

[0033] 3. The specialized tool provided by this utility model can accurately and quickly remove secondary plug-in pins. Field test data shows that pin replacement can be completed by a single person using this tool, with the average removal time shortened to less than 0.5 days, improving efficiency by at least 100% compared to traditional methods. Furthermore, in multiple simulation and actual field operation tests, the damage rate of the pin fixing spring clips is low, almost achieving zero damage, effectively ensuring the stability of the circuit breaker control circuit and greatly reducing the risk of equipment failure due to maintenance.

[0034] 4. The specialized tool provided by this utility model features an ergonomic handle design, easy-to-understand size adjustment operation, and a concise and clear usage process, enabling operators to master its use without extensive and complex training. Even newly hired maintenance personnel can quickly get started after simple guidance, effectively shortening the training cycle for maintenance personnel and improving the overall operation and maintenance efficiency of nuclear power plants.

[0035] 5. Considering the diversity of pin specifications in practical applications, the toothed tube design of this utility model is scalable. By adopting a nested structure, operators can easily replace pins with a simple rotation or push-pull sleeve, ensuring precise fit, depending on the pin diameter. This greatly improves the tool's versatility; one set of tools can meet the vast majority of pin replacement needs in nuclear power plants.

[0036] 6. To ensure the long-term reliable operation of the specialized tool in the harsh environment of a nuclear power plant, special materials were selected for each component. The corrosion-resistant special steel of the main structure not only possesses high strength and high toughness, enabling it to withstand long-term erosion in various environments, but also exhibits excellent thermal stability, preventing performance degradation under high or low temperature conditions. To address the issue of easy wear on the support tube, surface strengthening treatment technology was employed to form a high-hardness, low-friction coefficient wear-resistant layer on the inner surface of the syringe, effectively extending the tool's service life. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the special tool in this utility model;

[0038] Figure 2 An exploded view of the special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant, as described in this utility model.

[0039] Figure 3 This is a schematic diagram of the handle in the nuclear power plant of this utility model;

[0040] Figure 4 This is a schematic diagram of the connecting pipe in this utility model;

[0041] Figure 5 This is a schematic diagram of the toothed tube structure in this utility model;

[0042] Figure 6 This is a schematic diagram of the structure in this utility model where the support tooth tube is connected to the secondary insertion pin.

[0043] Explanation of the attached diagram numbers: 1. Handle, 2. Connecting tube, 3. Support tooth tube, 4. Screw hole, 5. Lead screw, 6. Sleeve, 7. Syringe, 8. Secondary insertion pin. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0048] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0049] Example 1

[0050] See Figures 1 to 3 This embodiment provides a special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant, including a handle 1, a connecting tube 2, and a toothed tube 3. One end of the connecting tube 2 is connected to the handle 1, and the other end of the connecting tube 2 is connected to the toothed tube 3. The toothed tube 3 is used to replace the secondary pins 8.

[0051] The toothed tube 3 is composed of a sleeve 6 and a syringe 7. One end of the sleeve 6 is provided with the syringe 7, and the other end of the sleeve 6 is connected to the connecting tube 2. The outer diameter φ1 of the syringe 7 is 5mm, and the inner diameter φ2 of the syringe 7 is 4.5mm.

[0052] In this embodiment, both the upper and lower ends of the connecting pipe 2 are provided with lead screws 5, and the upper and lower ends of the connecting pipe 2 are respectively connected to the handle 1 and the toothed pipe 3 through a lead screw 5.

[0053] In this embodiment, the outer surface of the lead screw 5 is provided with threads.

[0054] In this embodiment, the handle 1 and the sleeve 6 are both provided with screw holes 4 on the side adjacent to the lead screw 5, and the lead screw 5 is threadedly connected to the screw holes 4.

[0055] In this embodiment, the length h1 of the handle 1 is 60mm. The handle 1 adopts an ergonomic arc design and has a non-slip textured surface for the operator to grip and apply force. This design fully considers the operator's grip comfort and ease of application during actual operation, and can effectively improve the accuracy and stability of operation.

[0056] In this embodiment, the length h2 of the connecting pipe 2 is 50mm.

[0057] In this embodiment, the total length h3 of the toothed tube 3 is 40mm.

[0058] In this embodiment, the length h6 of the sleeve 6 is 10mm and the diameter M6 of the sleeve 6 is 10mm.

[0059] In this embodiment, the length h7 of the syringe 7 is 30mm.

[0060] In this embodiment, the handle 1 and the connecting tube 2 are made of steel.

[0061] In this embodiment, the handle 1 is made of high-strength engineering special steel, which has corrosion resistance to extend its service life.

[0062] In this embodiment, the connecting tube 2 is made of corrosion-resistant special steel. This steel has high strength and high toughness, and can withstand long-term corrosion in different environments, ensuring the long-term reliable use of the tool in the special environment of a nuclear power plant. At the same time, it can effectively transmit and rationally distribute the external force applied by the operator, and work closely with the handle 1 and the support tube 3 to form a stable mechanical support system, ensuring the smooth and stable removal of the insertion pin.

[0063] In this embodiment, the inner surface of the syringe 7 of the toothed tube 3 is subjected to surface strengthening treatment to form a wear-resistant layer with high hardness and low friction coefficient, so as to extend the service life of the tool.

[0064] In addition, this embodiment also provides a method for using a special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant. The specific steps are as follows:

[0065] S1. The operator selects the size of the support tube 3 according to the diameter and length specifications of the secondary insertion pin 8 to be replaced, and selects the appropriate size of the inner diameter of the support tube 3 according to the diameter specification. The appropriate support tube 3 is then replaced to achieve accurate and reliable pin retraction.

[0066] S2. Hold handle 1, align the support tube 3 with the secondary insertion pin 8, and slowly apply axial force to make the insertion pin smoothly exit under the action of the support tube 3. During this process, pay attention to the status of the retaining spring. If the retaining spring is found to be deformed, stop applying force immediately and adjust the operating angle or force to ensure that no damage is caused.

[0067] S3. After the pin is removed, insert the new pin into the original position, reverse the operation of the support tube 3, that is, push the pin to insert it into place, and at the same time check the pin fixing status and circuit connection status again. After confirming that there are no errors, the pin replacement operation is completed.

[0068] Throughout the entire process of use, operators must strictly abide by the operating procedures and regularly maintain the tools, such as cleaning and lubrication, to ensure the long-term stable use of the tools.

[0069] Example 2

[0070] See Figures 1 to 3 This embodiment provides a special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant. Except that the outer diameter φ1 of the syringe 7 is 4mm and the inner diameter φ2 of the syringe 7 is 3.5mm, the rest is the same as in Embodiment 1.

[0071] Example 3

[0072] See Figures 1 to 3 This embodiment provides a special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant. Except that the outer diameter φ1 of the syringe 7 is 3mm and the inner diameter φ2 of the syringe 7 is 2.5mm, the rest is the same as in Embodiment 1.

[0073] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant, characterized in that, It includes a handle (1), a connecting tube (2) and a toothed tube (3). One end of the connecting tube (2) is connected to the handle (1), and the other end of the connecting tube (2) is connected to the toothed tube (3). The toothed tube (3) is used to replace the secondary insertion pin (8). The toothed tube (3) consists of a sleeve (6) and a syringe (7). One end of the sleeve (6) is provided with the syringe (7), and the other end of the sleeve (6) is connected to the connecting tube (2). The outer diameter φ1 of the syringe (7) is in the range of 3 to 5 mm, and the inner diameter φ2 of the syringe (7) is in the range of 2.5 to 4.5 mm.

2. The special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, Both ends of the connecting pipe (2) are provided with lead screws (5), and the upper and lower ends of the connecting pipe (2) are respectively connected to the handle (1) and the toothed pipe (3) through a lead screw (5).

3. The special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 2, characterized in that, The outer surface of the lead screw (5) is provided with threads.

4. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 3, characterized in that, The handle (1) and sleeve (6) are each provided with a screw hole (4) on the side adjacent to the lead screw (5), and the lead screw (5) is threadedly connected to the screw hole (4).

5. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The length h1 of the handle (1) is 55-65 mm.

6. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The length h2 of the connecting pipe (2) is 45-55 mm.

7. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The total length h3 of the toothed tube (3) is 33-47 mm.

8. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The length h6 of the sleeve (6) is 8-12 mm, and the diameter M6 of the sleeve (6) is 8-12 mm.

9. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The length h7 of the syringe (7) is 25-35 mm.

10. A special tool for replacing the secondary pins of a medium-voltage circuit breaker in a nuclear power plant according to claim 1, characterized in that, The handle (1) and the connecting tube (2) are made of steel.

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