Sealing device for airtightness test of corrugated aluminum sheath power cable and airtightness detection method

Abstract

The invention relates to the technical field of cable manufacturing inspection and detection, in particular to a sealing device for a corrugated aluminum sheath power cable air tightness test and an air tightness detection method. The sealing device for the air tightness test of the corrugated aluminum sheath power cable comprises an enclasping piece (2), one end of the enclasping piece (2) is detachably connected with a sealing cover (3), and one side, close to the enclasping piece (2), of the sealing cover (3) is provided with a sealing ring (4). The device is novel in structure, easy and convenient to operate, reasonable in overall layout and high in compactness, mounting and dismounting at the end of the cable are facilitated, and the stability and sealing durability of the overall structure under test pressure can be ensured through the rigidity of the metal components and a multiple bolt locking mode; the problem of sealing failure caused by a thin structure of a traditional disposable sealing device is effectively solved, and the device can be repeatedly used and run for a long service life.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing inspection and testing technology, and in particular to a sealing device and airtightness testing method for corrugated aluminum sheathed power cables. Background Technology

[0002] The power energy industry is a crucial foundational energy industry in national economic development, and the wire and cable industry is the second largest supporting industry, with demand for cables maintaining continuous growth over the long term. Corrugated aluminum-sheathed high-voltage power cables, with their excellent mechanical properties and bending ability, superior transmission capacity, and environmental resistance, are widely used in urban underground power transmission networks. The corrugated aluminum sheath not only bears the short-circuit current during power transmission system faults but also prevents water molecules from entering the cable, reducing power transmission system faults caused by moisture and extending cable lifespan. After production, the corrugated aluminum sheath should undergo an airtightness test to ensure its continuous and tight seal.

[0003] The airtightness test requirements for corrugated aluminum-sheathed power cables typically involve filling the cable with nitrogen (N2) at a pressure of 0.40±0.05MPa for 2 hours without any leakage. Currently, the cable industry only has the above-mentioned requirements for airtightness testing of corrugated aluminum-sheathed power cables, lacking a unified and standardized testing device to ensure consistent and valid test results. Most cable manufacturers use disposable testing devices such as heat-shrink caps with air nozzles or welded aluminum metal caps. This not only fails to guarantee the sealing of the testing device but also results in material waste due to the inability to reuse the device.

[0004] Therefore, those skilled in the art are dedicated to developing a novel and easy-to-operate sealing device and airtightness testing method for corrugated aluminum sheathed power cables. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a sealing device and a method for airtightness testing of corrugated aluminum sheathed power cables.

[0006] To achieve the above objectives, the present invention provides a sealing device for airtightness testing of corrugated aluminum sheathed power cables, including a clamping member, one end of which is detachably connected to a sealing cover, and a sealing ring is provided on the side of the sealing cover near the clamping member.

[0007] Preferably, the clamping member includes a first semi-circular clamping plate and a second semi-circular clamping plate hinged together by a hinge structure, the working surfaces of the first semi-circular clamping plate and the second semi-circular clamping plate forming a circular clamping channel for accommodating and clamping the cable core.

[0008] Preferably, at least one pair of clamping screw holes are provided on the free ends of the first and second semicircular clamps away from the hinge structure, and the first and second semicircular clamps are locked together by clamping bolts passing through them, thereby tightening the cable core.

[0009] Preferably, both the first semicircular clamping plate and the second semicircular clamping plate have an axial clamping section extending along the axial direction of the cable core and a radial connecting section perpendicular to the axial clamping section, wherein the radial connecting section is provided with a plurality of first locking screw holes.

[0010] Preferably, the sealing cover is provided with a plurality of second locking screw holes, the positions of the plurality of second locking screw holes corresponding one-to-one with the first locking screw holes.

[0011] Preferably, a locking bolt is provided in the first locking screw hole and the second locking screw hole, and the locking bolt fixes the sealing cover to the end of the clamping member.

[0012] Preferably, the sealing cover is provided with an air inlet, and an air inlet is installed on the air inlet.

[0013] The present invention also provides a method for testing the air tightness of corrugated aluminum sheathed power cables, which is accomplished using the sealing device for air tightness testing of corrugated aluminum sheathed power cables as described above.

[0014] Preferably, it includes the following steps:

[0015] S1. Install clamping components at both ends of the cable core to be tested;

[0016] S2. Install sealing caps on the two clamping parts respectively, and then use locking bolts to press the sealing caps onto the ends of the clamping parts, so that the sealing ring between the mating surfaces is compressed and deformed, thereby forming an effective seal;

[0017] S3. Simultaneously fill the inside of the cable core with dry high-purity nitrogen through the air inlets on the sealing caps at both ends of the cable core until the gas pressure reaches the preset test pressure value.

[0018] S4. Stop inflation and start the pressure holding timer;

[0019] S5. During or after the specified pressure holding time, measure the gas pressure inside the cable core through the air inlet.

[0020] S6. Compare the pressure value measured in S5 with the initial test pressure value in S3, and determine whether the air tightness of the tested cable core is qualified based on the pressure drop.

[0021] The beneficial effects of this invention are: the invention has a novel structure, is easy to operate, has a reasonable overall layout, and is highly compact. It not only facilitates installation and disassembly at the cable end, but also ensures the stability and sealing durability of the overall structure under test pressure through the rigidity of the metal components themselves and the multiple bolt locking method. It effectively avoids the sealing failure problem caused by the thin structure of traditional disposable sealing devices, and realizes the reusability and long service life of the device. Attached Figure Description

[0022] Figure 1 This is a side view of the clamping component in a specific embodiment of the present invention.

[0023] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure of AA.

[0024] Figure 3 This is a side view of the sealing cap in a specific embodiment of the present invention.

[0025] Figure 4 yes Figure 3 A schematic diagram of the cross-sectional structure of BB.

[0026] Figure 5 This is an assembly diagram of a specific embodiment of the present invention.

[0027] Figure 6 This is a schematic flowchart of the airtightness testing method for wrinkled aluminum-sheathed power cables according to the present invention.

[0028] 1. Cable core; 2. Clamping component; 2a. Hinge structure; 21. First semi-circular clamping plate; 22. Second semi-circular clamping plate; 23. Clamping screw hole; 24. Clamping bolt; 25. Axial clamping section; 26. Radial connecting section; 26a. First locking screw hole; 3. Sealing cap; 31. Second locking screw hole; 32. Inflation hole; 33. Inflation nozzle; 4. Sealing ring; 5. Locking bolt. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the present invention and for simplifying the description, and 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 manner. Therefore, they should not be construed as limitations on the present invention. Terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] like Figure 1-2As shown, this invention provides a sealing device for airtightness testing of corrugated aluminum-sheathed power cables, including a clamping member 2 with an overall cylindrical structure. The cylindrical design allows the clamping member 2 to completely cover the circumferential surface of the cable core 1, providing a stable and reliable clamping foundation for subsequent sealing operations. Specifically, the clamping member 2 includes a first semi-circular clamping plate 21 and a second semi-circular clamping plate 22 hinged together by a hinge structure 2a. The first semi-circular clamping plate 21 and the second semi-circular clamping plate 22 can open and close around the hinge axis. When the first semi-circular clamping plate 21 and the second semi-circular clamping plate 22 are closed, their inner working surfaces together form a complete circular clamping channel for accommodating the cable core 1.

[0031] like Figure 2 As shown, to achieve the clamping function of the clamping member 2, at least one pair of clamping screw holes 23 are correspondingly provided on the free ends of the first semicircular clamping plate 21 and the second semicircular clamping plate 22 away from the hinge structure 2a, and clamping bolts 24 are inserted into them. The first semicircular clamping plate 21 and the second semicircular clamping plate 22 are locked together by the tightening action of the clamping bolts 24 and the matching nuts, thereby clamping the cable core 1 and effectively preventing loosening or leakage caused by the increase of internal pressure during the test. Specifically, in this embodiment, the clamping bolts 24 are set in two sets, and the two sets of clamping bolts 24 are arranged alternately. In other embodiments, other numbers of clamping bolts 24 can also be set according to actual needs.

[0032] In addition, both the first semi-circular clamping plate 21 and the second semi-circular clamping plate 22 have an axial clamping section 25 extending along the axial direction of the cable core 1 and a radial connecting section 26 perpendicular to the axial clamping section 25. The axial clamping section 25 directly performs the radial clamping function of the cable core 1, while the radial connecting section 26 provides an installation base for subsequent components. Several first locking screw holes 26a are provided circumferentially on the radial connecting section 26. In this embodiment, four sets of first locking screw holes 26a are provided, and the four sets of first locking screw holes 26a are evenly distributed circumferentially along the end face of the radial connecting section 26, aiming to achieve stable and reliable clamping of the sealing cover 3 through multiple connection points. In other embodiments, the specific number of locking screw holes can be adaptively adjusted according to the sealing diameter and connection strength requirements.

[0033] like Figure 3-4 As shown, a sealing cap 3 is detachably connected to one end of the clamping member 2. This sealing cap 3 is disc-shaped and made of aluminum, possessing lightweight and corrosion-resistant properties. A sealing ring 4 is provided on the side of the sealing cap 3 near the clamping member 2. When the sealing cap 3 is pressed against the clamping member 2, the sealing ring 4 is compressed and deformed, forming an axial end face static seal. The sealing cap 3 also has an inflation hole 32 for installing an inflation nozzle 33. The inflation nozzle 33 serves as the interface between the external air source and the internal cavity of the cable core 1. During the test, it is used to inject high-pressure nitrogen into the cable core 1 and plays a sealing and pressure monitoring role during the pressure holding phase.

[0034] like Figure 5 As shown, the detachable connection between the sealing cap 3 and the clamping member 2 is a bolted connection. Specifically, the sealing cap 3 has several second locking screw holes 31 arranged circumferentially, and the positions of these second locking screw holes 31 correspond one-to-one with several first locking screw holes 26a provided on the radial connecting section 26 of the clamping member 2. Locking bolts 5 are matched between the first locking screw holes 26a and the second locking screw holes 31. Through the tightening action of the locking bolts 5 and matching nuts passing through the first locking screw holes 26a and the second locking screw holes 31, the sealing cap 3 is firmly pressed against the end of the clamping member 2. This connection structure not only achieves reliable fixation of the sealing cap 3, but more importantly, through the uniform clamping force provided by the bolts, it ensures that the sealing ring 4 obtains a stable and sufficient compression, thereby maintaining a durable and effective sealing state throughout the test. At the same time, this bolted design also facilitates the disassembly and reuse of the device after the test. In other embodiments, the sealing cap 3 and the clamping member 2 can also adopt other similar connection methods, such as snap-fit, adhesive, or magnetic connection.

[0035] This invention features a novel structure, simple operation, reasonable overall layout, and strong compactness. It not only facilitates installation and disassembly at the cable end, but also ensures the stability and sealing durability of the overall structure under test pressure through the rigidity of the metal components and multiple bolt locking methods. It effectively avoids the sealing failure problem caused by the thin structure of traditional disposable sealing devices, and realizes the reusability and long service life of the device.

[0036] like Figure 6 As shown, the present invention also provides a method for testing the airtightness of corrugated aluminum-sheathed power cables, which is accomplished using the sealing device for airtightness testing of corrugated aluminum-sheathed power cables as described above, and specifically includes the following steps:

[0037] S1. Wrap the first semi-circular clamp 21 and the second semi-circular clamp 22 around the outer surface of the corrugated aluminum sleeve of the cable core 1 and close them together. After closing, insert clamping bolts 24 into the clamping edges of the first semi-circular clamp 21 and the second semi-circular clamp 22 and tighten them, so that the clamping member 2 is firmly clamped to the end of the cable core 1. The other end of the cable core to be tested is installed with another clamping member 2 using the same operation.

[0038] S2. Align the sealing cap 3 with the end of the clamping member 2, so that the second locking screw hole 31 on the sealing cap 3 is aligned with the first locking screw hole 26a on the clamping member 2. Insert the locking bolt 5 and tighten it, so that the sealing ring 4 between the mating surfaces of the sealing cap 3 and the clamping member 2 is compressed and deformed, forming an effective end face seal.

[0039] S3. Simultaneously fill the cable core 1 with dry nitrogen gas of ≥99.99% purity through the air inlets 33 on the sealing caps 3 at both ends of the cable core 1, and slowly pressurize it to the specified test pressure. In this embodiment, the specified test pressure is 0.40±0.05MPa. Other embodiments may set other standard pressure values ​​according to the actual conditions of the cable core 1.

[0040] S4. Once the internal pressure of cable core 1 reaches the preset value, the air supply is turned off, the initial pressure value is recorded, and a timer is started simultaneously to begin the pressure holding test. In this embodiment, the pressure holding test lasts for 2 hours. In other embodiments, other pressure holding times can be set according to the length and thickness of cable core 1. During the pressure holding period, the internal pressure value of cable core 1 can be measured at intervals to refine the measurement data.

[0041] S5. After the specified pressure holding time is reached, the gas pressure inside the cable core 1 is measured by connecting a pressure gauge through the same air inlet 33.

[0042] S6. Compare the pressure value measured in S5 with the initial test pressure value recorded in S3. If the pressure drop is within the allowable range (e.g., ≤0.01MPa), the cable is deemed to be airtight; otherwise, it is deemed to be unqualified.

[0043] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A sealing device for airtightness testing of corrugated aluminum-sheathed power cables, characterized in that: It includes a clamping component (2), one end of which is detachably connected to a sealing cap (3), and a sealing ring (4) is provided on the side of the sealing cap (3) near the clamping component (2).

2. The sealing device for airtightness testing of corrugated aluminum sheathed power cables as described in claim 1, characterized in that: The clamping member (2) includes a first semi-circular clamping plate (21) and a second semi-circular clamping plate (22) hinged together by a hinge structure (2a). The working surfaces of the first semi-circular clamping plate (21) and the second semi-circular clamping plate (22) enclose a circular clamping channel for accommodating and clamping the cable core (1).

3. The sealing device for airtightness testing of corrugated aluminum sheathed power cables as described in claim 2, characterized in that: At least one pair of clamping bolt (24) holes are provided on the free end side of the first semicircular clamp (21) and the second semicircular clamp (22) away from the hinge structure (2a), and the first semicircular clamp (21) and the second semicircular clamp (22) are locked together by the clamping bolts (24) inserted therein, thereby tightening the cable core (1).

4. The sealing device for airtightness testing of corrugated aluminum-sheathed power cables as described in claim 2 or 3, characterized in that: The first semicircular clamp (21) and the second semicircular clamp (22) each have an axial clamping section extending along the axial direction of the cable core (1) and a radial connecting section (26) perpendicular to the axial clamping section. The radial connecting section (26) is provided with a plurality of first locking screw holes (26a).

5. The sealing device for airtightness testing of corrugated aluminum sheathed power cables as described in claim 4, characterized in that: The sealing cover (3) is provided with a plurality of second locking screw holes (31), and the positions of the plurality of second locking screw holes (31) correspond one-to-one with the first locking screw holes (26a).

6. The sealing device for airtightness testing of corrugated aluminum sheathed power cables as described in claim 5, characterized in that: Locking bolts (5) are provided in the first locking screw hole (26a) and the second locking screw hole (31), and the locking bolts (5) fix the sealing cover (3) to the end of the clamping member (2).

7. The sealing device for airtightness testing of corrugated aluminum-sheathed power cables as described in claim 1, characterized in that: The sealing cover (3) is provided with an air inlet (32), and an air inlet (33) is installed on the air inlet (32).

8. A method for testing the airtightness of corrugated aluminum-sheathed power cables, characterized in that: The airtightness test of corrugated aluminum sheathed power cables as described in any one of claims 1-7 is performed using a sealing device.

9. The method for testing the airtightness of corrugated aluminum-sheathed power cables as described in claim 8, characterized in that, Specifically, the following steps are included: S1. Install clamping parts (2) at both ends of the cable core (1) to be tested. S2. Install sealing caps (3) on the two clamping parts (2) respectively, and then use locking bolts (5) to press the sealing caps (3) onto the ends of the clamping parts (2), so that the sealing rings (4) between their mating surfaces are compressed and deformed, thereby forming an effective seal; S3. Through the air inlet (33) on the sealing cap (3) at both ends of the cable core (1), dry high-purity nitrogen gas is simultaneously injected into the interior of the cable core (1) until the gas pressure reaches the preset test pressure value. S4. Stop inflation and start the pressure holding timer; S5. During or after the specified pressure holding time, measure the gas pressure inside the cable core (1) through the air inlet (33). S6. Compare the pressure value measured in S5 with the initial test pressure value in S3, and determine whether the air tightness of the tested cable core (1) is qualified based on the pressure drop.

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