A method for detecting the sealing property of a cable

Abstract

The application discloses a cable sealing detection method in the field of cable sealing detection, and comprises the following steps: S101, sealing detection, S1011, installing a leak detection joint connected with a leak detector on one end of the cable and performing sealing treatment, vacuumizing the inside of the cable through the leak detector, peeling off the cable shielding layer about 20cm±0.5cm on the other end of the cable, wrapping a helium cover outside the cable insulation layer and the cable shielding layer respectively, and detecting the cable shielding layer and the cable insulation layer of all types of cables; S10111, vacuumizing the whole cable by using the leak detector, wrapping the cable insulation layer with an aluminum-coated film after the background is stable, and filling in a helium source; the application can detect the sealing performance between each layer of the cable, and can detect the sealing performance of each sealing channel of the cable compared with the prior leak detection method.

Description

Technical Field

[0001] This invention relates to the field of cable sealing performance testing, specifically a method for testing the sealing performance of cables. Background Technology

[0002] Cables consist of a conductor (usually a copper core), an insulation layer, a shielding layer, etc. In the manufacturing process of cables, the sealing performance is generally not considered. There are gaps between the conductor and the insulation layer, and between the shielding layer and the protective / insulation layer, which form leakage channels.

[0003] To achieve leak detection of cables or fiber optic channels, commonly used methods such as bubble detection, differential pressure detection, and ultrasonic leak detection are insufficient for accurately detecting and assessing the leakiness of cable channels. Only highly sensitive helium mass spectrometry leak detection methods can be employed. However, existing methods for cable leak detection cannot accurately detect the sealing performance between different layers of the cable, resulting in poor accuracy. Furthermore, during the testing process, uneven stress on the sealing areas during equipment installation often leads to errors in the test results. Therefore, those skilled in the art provide a cable leak detection method to address the problems mentioned in the background section. Summary of the Invention

[0004] The purpose of this invention is to provide a method for testing the sealing performance of cables, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for testing the sealing performance of a cable, the equipment used in the method including a leak detection connector installed at one end of the cable, the cable further including a conductor, a cable insulation layer, a cable shielding layer, and a cable protective layer, comprising the following steps:

[0007] S101, Sealing Inspection

[0008] S1011. Install a leak detection connector connected to the leak detector at one end of the cable and seal it. Vacuum the inside of the cable using the leak detector. Peel 20cm±0.5cm of the cable shield at the other end of the cable. Wrap helium covers around the cable insulation layer and the cable shield, respectively. Test the cable shield and cable insulation layers of all types of cables.

[0009] S10111. Vacuum the entire cable using a leak detector. After the base is stable, wrap the cable insulation layer with an aluminum-plated film and fill it with a helium source. The aluminum-plated film constitutes a helium shroud II.

[0010] S10112. After the cable insulation layer test is completed and the background signal is basically stable, install the helium cover at the end of the cable shielding layer and fill it with helium to check for leaks in the cable shielding layer.

[0011] S102. Acquisition of Experimental Data

[0012] The leak detector's detection range is 10. -13 Pa·m 3 / s~10 -2 Pa·m 3 / s, When the cable's leak detection rate exceeds the leak detector's upper limit, this experiment obtains detection data by reducing the helium concentration.

[0013] S103, Experimental Data Processing

[0014] The actual leak rate of the test piece is calculated by comparing the increase in the leak detector's output signal caused by the standard leak with the measured signal of the test piece, as shown in the following formula:

[0015] ·

[0016] Where: Q - leak rate of the inspected part, Pa·m 3 / s;

[0017] I - The increase in the leak detector output signal caused by the tested component, Pa·m 3 / s;

[0018] I0 - Leak detector background signal value, Pa·m 3 / s;

[0019] I sp - The increase in the leak detector output signal caused by a standard leak, in Pa·m 3 / s;

[0020] Q sp -Standard leak nominal value, Pa·m 3 / s;

[0021] γ - Volume concentration of He in the tested sample.

[0022] Furthermore, the concentration of the helium source introduced in step S10111 is approximately 100%.

[0023] As a further aspect of the present invention: a method for testing the sealing performance of a cable, wherein a sealant is provided between the leak detection connector and the cable, a helium cover one is provided around the junction of the cable protective layer and the cable insulation layer, and a helium cover two is provided around the junction of the cable insulation layer and the conductor. Both the helium cover one and the helium cover two are connected to a helium source bottle through gas guide pipes, and both gas guide pipes are equipped with shut-off valves through pipe joints.

[0024] As a further aspect of the present invention: both the helium shield one and the helium shield two are fixedly provided with sealing connectors at the connection points with the cables. The sealing connectors include a fixed sleeve, two locking studs threaded to opposite positions on the outer wall of the fixed sleeve, a locking handle integrally formed on one end of the locking studs, a locking block rotatably disposed on the other end of the locking studs, a locking protective pad disposed on the inner wall of the locking block, an annular inflatable rubber sealing sleeve disposed on the inner wall of the fixed sleeve on one side of the locking studs, an air inlet pipe integrally formed on the outer wall of the annular inflatable rubber sealing sleeve and penetrating the fixed sleeve, and an air inlet valve disposed on the air inlet pipe.

[0025] As a further embodiment of the present invention: the air intake pipe is connected to the air intake valve by a pipe clamp, the locking block has a U-shaped structure, and the locking block is bonded to the locking protective pad, and the locking stud is connected to the fixing sleeve by a thread.

[0026] As a further embodiment of the present invention: the two sealing connectors on the first helium shield respectively mate with the outer circular surfaces of the cable protection layer and the cable insulation layer, and the sealing connector on the second helium shield mates with the outer circular surface of the cable insulation layer.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention can detect the sealing performance between different layers of a cable, and compared with existing leak detection methods, it can accurately detect the sealing performance of each sealing channel of the cable.

[0029] 2. This invention allows for the installation of helium shield one and helium shield two. By rotating the locking stud, the locking block can be moved to the opposite direction, clamping the installation part. Then, air is injected into the annular rubber sealing sleeve through the inflation tube, forming high pressure, which firmly adheres to the cable for sealing. The pressure at the sealing part is uniform, which can greatly improve the sealing effect. This solves the problem of air leakage caused by uneven pressure in some areas when using clamps for clamping, making it safer and more reliable, and ensuring the accuracy of measurement data. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a cross-sectional view of the sealing connector in this invention;

[0032] Figure 3 This is a left view of the locking stud and locking block after they are connected in this invention.

[0033] In the diagram: 1. Leak detector; 2. Leak detection connector; 3. Sealant; 4. Cable protection layer; 5. Helium shroud one; 6. Cable insulation layer; 7. Helium shroud two; 8. Helium source bottle; 9. Sealing connector; 901. Fixing sleeve; 902. Locking stud; 903. Locking handle; 904. Locking block; 905. Annular inflatable rubber sealing sleeve; 906. Air inlet pipe; 907. Air inlet valve; 908. Locking protective pad. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figures 1-3 In this embodiment of the invention, a method for testing the sealing performance of a cable includes the following steps:

[0036] S101, Sealing Inspection

[0037] S1011. Install a leak detection connector 2 connected to the leak detector 1 at one end of the cable and seal it. Use the leak detector to evacuate the inside of the cable. Peel off 20cm±0.5cm of the cable shielding layer at the other end of the cable. Wrap helium covers around the cable insulation layer and the cable shielding layer respectively. Test the cable shielding layer and the cable insulation layer of all types of cables.

[0038] S10111. Use a leak detector 1 to evacuate the entire cable. After the background is stable, use an aluminum-plated film to wrap the cable insulation layer and fill it with a helium source. The aluminum-plated film forms a helium shroud 2 (7).

[0039] S10112. After the cable insulation layer test is completed and the background signal is basically stable, install the helium cover-5 at the end of the cable shielding layer and fill it with helium source to check for leaks in the cable shielding layer.

[0040] S102. Acquisition of Experimental Data

[0041] The detection range of leak detector 1 is 10. -13 Pa·m 3 / s~10 -2 Pa·m 3 / s, When the detection leakage rate of the cable exceeds the upper limit of the range of the leak detector 1, this experiment obtains detection data by reducing the helium concentration;

[0042] S103, Experimental Data Processing

[0043] The actual leakage rate of the test piece is calculated by the increase in the output signal of the leak detector 1 caused by the standard leak. The measured signal of the test piece is compared with the standard leak signal.

[0044] ·

[0045] Where: Q - leak rate of the inspected part, Pa·m 3 / s;

[0046] I - The increase in the output signal of leak detector 1 caused by the tested component, Pa·m 3 / s;

[0047] I0 - Leak detector 1 background signal value, Pa·m 3 / s;

[0048] I sp - The increase in the output signal of leak detector 1 caused by a standard leak, in Pa·m 3 / s;

[0049] Q sp -Standard leak nominal value, Pa·m 3 / s;

[0050] γ - Volume concentration of He in the tested sample.

[0051] In this embodiment, the concentration of the helium source filled in step S10111 is approximately 100%.

[0052] By adopting the above technical solution, the leak detection using helium mass spectrometry, which has high sensitivity, is better than 10. -11 Pa·m 3 The / s method is used to detect the sealing performance of cables. By measuring the magnitude of the helium leakage signal detected by the helium mass spectrometer leak detector 1, the leakage rate of the cable leakage channel is determined, and the sealing performance of the cable is interpreted. During the test, a vacuum is drawn at one end of the cable using the leak detector 1, and a helium source is applied to the cable insulation layer and the cable shielding layer respectively. Under the action of pressure difference and concentration difference, helium molecules enter the leakage channel inside the cable insulation layer and the cable shielding layer, and are thus detected by the leak detector 1. This method can detect the sealing performance between each layer of the cable, and compared with existing leak detection methods, it can accurately detect the sealing performance of each sealing channel of the cable.

[0053] In this embodiment, since the leakage rate of the cable shielding layer is too high, which exceeds the mass production range of the leak detector 1, the present invention uses a 1% helium concentration leak detection method to test the sealing performance of the 27 cables. The test results are shown in the table below.

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] Analysis of the table above shows that when the cable length is 10m to 50m and the cable cross-sectional diameter is 5mm to 29.5mm, the leakage signal of the cable shielding layer is relatively large, with a leakage rate range of 10%. -1 Pa·m 3 / s~10 -3 Pa·m 3 / s. The leakage rate is 10. -2 Pa·m 3 The largest proportion (64%) were in the / s range, and 10 -3 Pa·m 3 / s-level quantities account for 16%, 10 -1 Pa·m 3 The leakage rate in the / s range accounts for 20%. It can be assumed that the leakage rate of the shielding layer in a 10m-50m cable is around 10%. -2 Pa·m 3 The leakage rate is around the level of / s. However, the leakage rate of the insulation layer varies significantly compared to that of the cable shielding layer, with a difference of 10%. -1 Pa·m 3 / s~<10 -7 Pa·m 3 / s.

[0060] In this embodiment, the equipment used in this detection method includes a leak detection connector 2 installed at one end of the cable. The cable further includes a conductor, a cable insulation layer 6, a cable shielding layer, and a cable protective layer. A sealant 3 is provided between the leak detection connector 2 and the cable. A helium cover 5 is provided around the junction of the cable protective layer 4 and the cable insulation layer 6. A helium cover 7 is provided around the junction of the cable insulation layer 6 and the conductor. Both helium cover 5 and helium cover 7 are connected to a helium source bottle 8 through gas guide pipes, and both gas guide pipes are equipped with shut-off valves through pipe joints.

[0061] Among them, the junction of helium shield 1 5 and helium shield 2 7 with the cable is fixedly provided with sealing connectors 9. The sealing connectors 9 include a fixed sleeve 901, two locking studs 902 threaded to the outer wall of the fixed sleeve 901 at opposite positions, a locking handle 903 integrally formed at one end of the locking studs 902, a locking block 904 rotatably set at the other end of the locking studs 902, a locking protective pad 908 set on the inner wall of the locking block 904, an annular inflatable rubber sealing sleeve 905 set on the inner wall of the fixed sleeve 901 on one side of the locking studs 902, an air inlet pipe 906 integrally formed on the outer wall of the annular inflatable rubber sealing sleeve 905 and penetrating the fixed sleeve 901, and an air inlet valve 907 set on the air inlet pipe 906.

[0062] By adopting the above technical solution, when installing helium shroud 1-5 and helium shroud 2-7, rotating the locking stud 902 can drive the locking block 904 to move in the opposite direction, clamping the installation part tightly. Then, air is injected into the annular inflatable rubber sealing sleeve 905 through the air inflator tube, forming high pressure, which makes it firmly stick to the cable for sealing. The pressure at the sealing part is even, which can greatly improve the sealing effect and solve the problem of air leakage caused by uneven pressure in some areas when using clamps for clamping. It is safer and more reliable, ensuring the accuracy of measurement data.

[0063] The intake pipe 906 and the intake valve 907 are connected by a pipe clamp. The locking block 904 has a U-shaped structure and is bonded to the locking protective pad 908. The locking stud 902 and the fixing sleeve 901 are connected by threads. The locking protective pad 908 can play a protective role.

[0064] In this embodiment, the two sealing connectors 9 on the helium cover 5 respectively mate with the outer circular surfaces of the cable protection layer 4 and the cable insulation layer 6, and the sealing connectors 9 on the helium cover 7 mate with the outer circular surface of the cable insulation layer 6.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for testing the sealing performance of a cable, the equipment used in the method including a leak detection connector (2) installed at one end of the cable, the cable further including a conductor, a cable insulation layer (6), a cable shielding layer and a cable protective layer (4), a sealant (3) being provided between the leak detection connector (2) and the cable, a helium shield one (5) being provided around the junction of the end of the cable protective layer (4) and the cable insulation layer (6), and a helium shield two (7) being provided around the junction of the end of the cable insulation layer (6) and the conductor, both helium shield one (5) and helium shield two (7) being connected to a helium source bottle (8) via gas guide pipes, and both gas guide pipes being equipped with shut-off valves via pipe joints, characterized in that: Includes the following steps: S101, Sealing Inspection S1011. Install a leak detection connector (2) connected to the leak detector (1) at one end of the cable and seal it. Vacuum the inside of the cable using the leak detector. Peel off the cable shielding layer by 20cm ± 0.5cm at the other end of the cable. Wrap helium covers on the cable insulation layer (6) and the cable shielding layer respectively. Test the cable shielding layer and the cable insulation layer (6) of the cable. S10111. Use a leak detector (1) to evacuate the entire cable. After the base is stable, use an aluminum-plated film to wrap the cable insulation layer (6) and fill it with a helium source. The aluminum-plated film forms a helium shroud (7). S10112. After the cable insulation layer (6) is tested, once the background signal is basically stable, install the helium cover (5) at the end of the cable shielding layer and fill it with helium source to check for leaks in the cable shielding layer. S102. Acquisition of Experimental Data When the detection leakage rate of the cable exceeds the upper limit of the range of the leak detector (1), this experiment obtains detection data by reducing the helium concentration. S103, Experimental Data Processing The increase in the output signal of the leak detector (1) caused by the standard leak hole is calculated, and the measured signal of the tested part is compared with the standard leak hole signal. The resulting data is the actual leak rate of the tested part, as shown in the following formula: · ； Where: Q - leak rate of the inspected part, Pa·m 3 / s; I - Increase in the output signal of the leak detector (1) caused by the tested component, Pa·m 3 / s; I0-Leak Detector (1) Background signal value, Pa·m 3 / s; I sp - The increase in the output signal of the leak detector (1) caused by a standard leak, Pa·m 3 / s; Q sp -Standard leak nominal value, Pa·m 3 / s; γ - Volume concentration of He in the tested sample.

2. The method for testing the sealing performance of a cable according to claim 1, characterized in that: In step S10111, the concentration of the helium source is approximately 100%, and the detection range of the leak detector (1) is 10. -13 Pa·m 3 / s~10 -2 Pa·m 3 / s.

3. The method for testing the sealing performance of a cable according to claim 1, characterized in that: Both the helium shield 1 (5) and the helium shield 2 (7) are fixedly provided with sealing connectors (9) at the connection points with the cables. The sealing connectors (9) include a fixed sleeve (901), two locking studs (902) threaded to the outer wall of the fixed sleeve (901) at opposite positions, a locking handle (903) integrally formed at one end of the locking studs (902), a locking block (904) rotatably set at the other end of the locking studs (902), a locking protective pad (908) set on the inner wall of the locking block (904), an annular inflatable rubber sealing sleeve (905) set on the inner wall of the fixed sleeve (901) on one side of the locking studs (902), an air inlet pipe (906) integrally formed on the outer wall of the annular inflatable rubber sealing sleeve (905) and penetrating the fixed sleeve (901), and an air inlet valve (907) set on the air inlet pipe (906).

4. The method for testing the sealing performance of a cable according to claim 3, characterized in that: The intake pipe (906) and intake valve (907) are connected by a pipe clamp. The locking block (904) has a U-shaped structure and is bonded to the locking protective pad (908). The locking stud (902) and the fixing sleeve (901) are connected by a thread.

5. The method for testing the sealing performance of a cable according to claim 3, characterized in that: The two sealing connectors (9) on the first helium cover (5) respectively mate with the outer circular surfaces of the cable protection layer (4) and the cable insulation layer (6), and the sealing connectors (9) on the second helium cover (7) mate with the outer circular surface of the cable insulation layer (6).

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