Cable insulation wire core external diameter monitoring device and method

Abstract

The invention discloses a cable insulation wire core external diameter monitoring device and method, and relates to the technical field of cable detection. The cable insulation wire core outer diameter monitoring device is composed of a first fixing device, a second fixing device, a take-up and pay-off device and a position sensor, and the take-up and pay-off device comprises a measuring wire used for measuring the outer circumference of a cable; the first fixing device and the second fixing device are arranged in the axial direction of the cable, the cable is located between the first fixing device and the second fixing device, the position sensor is located between the first fixing device and the cable, and the take-up and pay-off device is installed on the second fixing device. By arranging the cable insulation core outer diameter monitoring device and combining the monitoring method, the coverage is wider compared with an existing sampling detection mode, and the outer diameter data change condition in the whole production process can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable detection, and particularly relates to a cable insulation core outer diameter monitoring device and method. BACKGROUND

[0002] The insulation core is a basic unit of power cable, which is composed of a conductor, an insulation layer and an inner and outer shielding layer. The commonly used structure of the power cable currently includes a three-core cable and a single-core cable. The three-core cable contains three groups of insulation cores, and the single-core cable contains one group of insulation cores. The insulation core is the core conductive structure of the cable, and its structure and material directly affect the performance of the cable. During the production and quality detection of the insulation core, the key parameters of the cable product need to be tested to confirm whether they meet the standard requirements.

[0003] In recent years, the state has vigorously promoted the green and low-carbonization of new power equipment industry. At present, the power cable mainly adopts cross-linked polyethylene insulation, which requires a long time and high energy consumption for cross-linking and degassing. Moreover, cross-linked polyethylene is a thermosetting material, which is difficult to recycle after retirement. The insulation layer of the non-cross-linked cable adopts a thermoplastic material, which does not need to be cross-linked and degassed, and has advantages in energy saving and environmental protection, becoming an important development direction of the cable industry at present.

[0004] Based on the domestic cable material research foundation and the application demand of the power grid unit, many cable manufacturing enterprises have carried out trial production of non-cross-linked polypropylene cables. By modifying the existing cross-linked polyethylene cable production line, the non-cross-linked polypropylene cable is produced. Due to the obvious difference between the non-cross-linked polypropylene material and the cross-linked polyethylene material, and the unstable performance of the polypropylene insulation material and the shielding material of different modification routes and batches, the cable insulation core size fluctuation is prone to occur when the glue output and the production speed are not matched during the production process, mainly reflected in the change of the insulation core outer diameter. The cable insulation core outer diameter directly affects the insulation material used in the production process, and the size cooperation with the water-blocking buffer layer and the metal sheath outside the cable insulation core. The size fluctuation of the insulation core outer diameter also has an impact on the interference fit when the cable accessories are installed. Therefore, for the non-cross-linked polypropylene cable whose manufacturing process is still being standardized, it is particularly necessary to strengthen the monitoring of the outer diameter data in the production process of the insulation core, and adjust the production speed according to the outer diameter change to make the outer diameter fluctuation within a certain range, so as to ensure the quality of the non-cross-linked polypropylene insulation cable product.

[0005] For the existing cross-linked polyethylene cable, the insulation core adopts a three-layer co-extrusion process, and the outer diameter is measured mainly through X-ray detection and sampling measurement. The non-cross-linked polypropylene cable also adopts the three-layer co-extrusion process, but the screw structure of the corresponding production line, the extrusion temperature of the head and the cooling method are changed. At present, the X-ray detection and sampling detection can also be used for the non-cross-linked polypropylene cable, but there are still the following shortcomings:

[0006] 1. Traditional sampling inspection methods involve taking a sample from any end of the cable reel and measuring its outer diameter. However, this method only provides the outer diameter at the sampling location and cannot fully represent the performance of the entire cable reel. When the outer diameter fluctuates, it is easy to miss some samples due to the limitations of the sampling location. Furthermore, this method involves inspection after production is completed. Even if a non-compliant result is found, the product must be scrapped, and no measures can be taken during the production process.

[0007] 2. Regarding sampling inspection methods, there are two existing methods for measuring the outer diameter: For small-section cables, a vernier caliper is used to measure the diameter in two mutually perpendicular directions, and the average value is taken to obtain the cable's outer diameter. However, this method obtains the diameter at two positions in the circumferential direction, which may contain errors. For large-section cables, a measuring tape is used to wrap around the cable to obtain the circumference, which is then converted into the outer diameter. This method is affected by the tightness of the wrapping and the tension, and may contain errors.

[0008] 3. X-ray inspection can be used in the production process. An X-ray transmitter and receiver are installed on both sides of the cable at the extruder head. The X-ray beam emitted by the transmitter is perpendicular to the cable, and the receiver receives the signal. The thickness of the cable insulation layer is obtained by calculating the intensity of the X-ray beam on the receiver. Currently, this method mainly outputs the insulation thickness. The obtained thickness data is affected by the X-ray emission and reception directions, resulting in inherent errors. Furthermore, due to installation location limitations, it cannot obtain the outer diameter data of the core after cooling and shaping.

[0009] Due to the above-mentioned deficiencies, there is currently no applicable method or device for monitoring the outer diameter during the production process of insulated wire cores, nor is there a method for adjusting the production speed based on the measured outer diameter data. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a device and method for monitoring the outer diameter of cable insulation cores. This invention proposes a method for monitoring the outer diameter of cable insulation cores during the production process and designs a corresponding monitoring device, which can be used for speed adjustment and quality control during the production process of non-crosslinked polypropylene cable insulation cores.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] This invention provides a cable insulation core outer diameter monitoring device, which consists of a first fixing device, a second fixing device, a take-up and release device, and a position sensor. The take-up and release device includes a measuring line for measuring the outer circumference of the cable. The first fixing device and the second fixing device are arranged along the cable axis, the cable is located between the first fixing device and the second fixing device, the position sensor is located between the first fixing device and the cable, and the take-up and release device is mounted on the second fixing device.

[0013] Preferably, the position sensor is cylindrical and has a circular hole for a cable to pass through.

[0014] Preferably, the position sensor is positioned axially near the first fixing device along the cable.

[0015] Preferably, the vertical distance between the first fixing device and the cable is equal to the vertical distance between the second fixing device and the cable.

[0016] Preferably, the position sensor is located directly below the circular cross-section of the cable.

[0017] This invention also provides a method for monitoring the outer diameter of cable insulation cores, comprising the following steps:

[0018] (1) Obtain the cable insulation core production speed V t ;

[0019] (2) Install the above-mentioned cable insulation core outer diameter monitoring device on the moving path of the cable insulation core;

[0020] (3) Obtain the outer circumference C0 of the cable insulation core before monitoring, and calculate the corresponding outer diameter R0 = C0 / π of the cable insulation core before monitoring; then obtain the spatial coordinates (X, π) of point A at the connection between the measuring line and the first fixing device. A Y A Z A The spatial coordinates of the position sensor (X0, Y0, Z0), and the spatial coordinates of point B at the connection point between the measuring line and the take-up / reel-out device (X...). B Y B Z B Obtain the total measurement line length L0 at this point, and then calculate the length error caused by the cable insulation core perforation.

[0021]

[0022] (4) Obtain the spatial coordinates (X, T) of the position sensor at time t. t Y t Z t ) and the total length L of the measuring line t Calculate the outer circumference of the cable insulation core at this time.

[0023]

[0024] (5) The outer circumference C of the cable insulation core at time t is obtained by calculation. t The outer diameter R of the cable insulation core at time t can then be calculated. t =C t / π.

[0025] Preferably, in the step (5), the pre-designed cable outer diameter R 设计 is obtained t , and the deviation of R 设计 is compared in real time, and when the deviation exceeds a preset range, the production speed Vt' = V t ×(R t 2 -R d 2 ) / (R 设计 2 -R d 2 ), R d is the diameter of the cable conductor.

[0026] Preferably, the preset range of the deviation is 4-6mm.

[0027] Preferably, in the step (2), the specific steps of installing the cable insulation core outer diameter monitoring device on the cable insulation core moving path are as follows:

[0028] S1: horizontally pull out the measuring line from the winding and unwinding device, pass through the round hole on the position sensor, and wrap around the cable insulation core;

[0029] S2: pass the measuring line through the round hole on the position sensor again and continue to pull in the horizontal direction to be fixed with the first fixing device, at this time the position sensor is located directly below the cable circular cross section, and the position sensor is kept rolling on the outer surface of the cable during the cable production process.

[0030] Preferably, in the S1, the measuring line is wrapped around the cable insulation core in a clockwise direction.

[0031] Compared with the prior art, the beneficial effects of the present application are as follows:

[0032] 1. The present application provides a method for measuring the outer diameter in real time during the production of the cable insulation core, which has a wider coverage than the existing sampling detection method and can obtain the outer diameter data changes during the entire production process.

[0033] 2. The monitoring method and the outer diameter monitoring device provided by the present application can be applied to various positions of the cable insulation core production line, and the data obtained by the present application is more accurate than the existing X-ray test at the machine head position, which solves the problem of real-time measurement of the outer diameter change of the non-crosslinked polypropylene cable after cooling.

[0034] 3. The present application uses the unwinding length and spatial coordinates obtained by the measuring line and the position sensor to calculate, and even if the test line has relative movement on the cable insulation core body, it will not affect the acquisition of the outer circumference length, and the corresponding calculation method has eliminated the error of the test system itself, and the outer circumference length of the measured cable can be accurately obtained.

[0035] 4. This invention calculates the cable outer diameter based on the outer circumference data. Compared with the direct diameter test method in the horizontal and vertical directions, it can better characterize the overall situation of large cross-section cables, laying the foundation for subsequent production speed adjustment.

[0036] 5. Based on real-time outer diameter data and production speed, this invention proposes an adjustment algorithm corresponding to the three-layer co-extrusion process of cable insulation core, avoiding the blindness of process adjustment when the outer diameter exceeds the standard. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the cable insulation core outer diameter monitoring device according to the present invention along the radial direction of the cable.

[0038] Figure 2 This is a schematic diagram of the cable insulation core outer diameter monitoring device according to the present invention along the cable axis.

[0039] Figure 3 This is a schematic diagram of the measuring line passing through the circular hole in the position sensor as described in this invention.

[0040] Figures 1-3 In the diagram: 1 is the first fixing device; 2 is the second fixing device; 3 is the wire take-up and release device; 4 is the measuring wire; 5 is the position sensor; 6 is the cable. Detailed Implementation

[0041] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the scope of protection and implementation of the present invention are not limited thereto.

[0042] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0043] Example 1

[0044] This embodiment discloses a device for monitoring the outer diameter of cable insulation cores, such as... Figures 1-2 As shown, the outer diameter monitoring device consists of a first fixing device 1, a second fixing device 2, a cable winding and unwinding device 3, and a position sensor 5. The cable winding and unwinding device 3 includes a measuring line 4 for measuring the outer circumference of the cable.

[0045] like Figure 2 As shown, the first fixing device 1 and the second fixing device 2 are arranged along the cable axis, the cable 6 is located between the first fixing device 1 and the second fixing device 2, the position sensor 5 is located between the first fixing device 1 and the cable 6, and the cable take-up and release device 3 is installed on the second fixing device 2.

[0046] like Figure 2As shown, the vertical distance between the first fixing device 1 and the cable 6 is equal to the vertical distance between the second fixing device 2 and the cable 6.

[0047] like Figure 2 As shown, the position sensor 5 adopts a smooth, rounded cylindrical design, and has a circular hole for the cable 6 to pass through. The position sensor 5 is positioned axially along the cable, close to the first fixing device 1. The position sensor 5 is located directly below the circular cross-section of the cable 6.

[0048] This embodiment also discloses a method for monitoring the outer diameter of cable insulation cores, including the following steps:

[0049] (1) Start the production of cable insulation cores and obtain the production speed V of cable insulation cores in real time. t This refers to the speed at which the conductor moves when three layers of co-extruded insulation and shielding are applied to the cable conductor.

[0050] (2) Install the cable insulation core outer diameter monitoring device at a selected location on the cable core movement path. Pull the measuring line horizontally from the take-up and release device, pass it through the circular hole on the position sensor, and wind it clockwise around the cable insulation core once. Then, pass the measuring line through the circular hole on the position sensor again and continue pulling it horizontally until it is fixed to the first fixing device. At this point, the position sensor, supported by the measuring line passing through the circular hole and its own weight, can remain directly below the circular cross-section of the cable. During cable production, the position sensor can always roll on the outer surface of the cable, preventing displacement with the cable body. The position sensor can obtain its spatial coordinate data in real time and transmit it wirelessly to the backend.

[0051] When the wire take-up and release device is under tension, it can release the measuring line and keep the measuring line in a straight line. When the wire take-up and release device is not under tension, it can retract the measuring line and keep the measuring line in a straight line, and obtain the total length of the released measuring line.

[0052] (3) Before starting monitoring, the original outer circumference C0 of the cable insulation core was measured and obtained. The corresponding outer diameter R0 of the cable insulation core before monitoring was calculated as C0 / π. The spatial coordinates (X, Y, π) of point A at the connection between the measuring line and the first fixing device were obtained. A Y A Z A The spatial coordinates of the position sensor (X0, Y0, Z0), and the spatial coordinates of point B at the connection point between the measuring line and the take-up / reel-out device (X...). B Y B Z B Obtain the total measurement line length L0 at this point, and then calculate the length error caused by the spatial coordinate deviation and the measurement line passing through the position sensor hole.

[0053]

[0054] (4) Real-time acquisition of the space coordinates (X t , Y t , Z t ) of the position sensor at time t during the monitoring process, and measurement of the total length L t of the measuring line, calculation of the outer circumference length C

[0055]

[0056] (5) According to the calculation, the outer circumference length C t of the insulated wire core at time t is obtained, and the outer diameter R t of the cable insulated wire core at time t is calculated as R t =C 设计 / π.

[0057] (6) The pre-designed outer diameter R t of the cable is obtained, and then the deviation between R 设计 and R t is compared in real time, and when the deviation exceeds the preset range (such as more than 4 mm), the production speed at this time is adjusted.

[0058] In the case that the extrusion amount of the insulation and shielding material is relatively fixed, and the cable conductor diameter is R d , the production speed is adjusted as Vt' = V t ×(R t 2 -R d 2 ) / (R 设计 2 -R d 2 ).

[0059] In summary, the real-time monitoring device for the outer diameter of the cable insulated wire core provided by the application has a structure design, including the arrangement mode, position sensor type and installation mode of the test line, and then combined with the monitoring method described in the application, it can be applied to each position of the cable insulated wire core production line. Compared with the existing X-ray test data obtained at the machine head position, the data is more accurate, and the problem of real-time measurement of the outer diameter change of the non-crosslinked polypropylene cable after cooling is solved.

[0060] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application and not to limit the protection scope of the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the application.

Claims

1. A device for monitoring the outer diameter of cable insulation cores, characterized in that, The outer diameter monitoring device consists of a first fixing device, a second fixing device, a cable winding and unwinding device, and a position sensor. The cable winding and unwinding device includes a measuring line for measuring the outer circumference of the cable. The first fixing device and the second fixing device are arranged along the cable axis, the cable is located between the first fixing device and the second fixing device, the position sensor is located between the first fixing device and the cable, and the cable winding and unwinding device is mounted on the second fixing device.

2. The cable insulation core outer diameter monitoring device as described in claim 1, characterized in that, The position sensor is cylindrical and has a circular hole for a cable to pass through.

3. The cable insulation core outer diameter monitoring device as described in claim 1, characterized in that, The position sensor is positioned axially along the cable near the first fixing device.

4. The cable insulation core outer diameter monitoring device as described in claim 1, characterized in that, The vertical distance between the first fixing device and the cable is equal to the vertical distance between the second fixing device and the cable.

5. The cable insulation core outer diameter monitoring device as described in claim 1, characterized in that, The position sensor is located directly below the circular cross-section of the cable.

6. A method for monitoring the outer diameter of cable insulation cores, characterized in that, Includes the following steps: (1) Obtain the production speed V of cable insulation core t ; (2) Install the cable insulation core outer diameter monitoring device as described in any one of claims 1-5 on the cable insulation core movement path; (3) Obtain the outer circumference C0 of the cable insulation core before monitoring, and calculate the corresponding outer diameter R0 = C0 / π of the cable insulation core before monitoring; then obtain the spatial coordinates (X, π) of point A at the connection between the measuring line and the first fixing device. A Y A Z A The spatial coordinates of the position sensor (X0, Y0, Z0), and the spatial coordinates of point B at the connection point between the measuring line and the take-up / reel-out device (X...). B Y B Z B Obtain the total measurement line length L0 at this point, and then calculate the length error caused by the cable insulation core perforation. (4) Obtain the spatial coordinates (X, T) of the position sensor at time t. t Y t Z t ) and the total length L of the measuring line t Calculate the outer circumference of the cable insulation core at this time. (5) The outer circumference C of the cable insulation core at time t is obtained by calculation. t The outer diameter R of the cable insulation core at time t can then be calculated. t =C t / π.

7. The method for monitoring the outer diameter of cable insulation cores as described in claim 6, characterized in that, In step (5), the pre-designed cable outer diameter R is obtained. 设计 Then compare R in real time t and R 设计 When the deviation exceeds the preset range, the production speed Vt' = V t ×(R t 2 -R d 2 ) / (R 设计 2 -R d 2 ), R d This refers to the diameter of the cable conductor.

8. The method for monitoring the outer diameter of cable insulation cores as described in claim 7, characterized in that, The preset range for the deviation is 4-6 mm.

9. The method for monitoring the outer diameter of cable insulation cores as described in claim 6, characterized in that, The specific steps for installing the cable insulation core outer diameter monitoring device on the cable insulation core moving path in step (2) are as follows: S1: Pull the measuring line horizontally out of the take-up and release device, pass it through the round hole on the position sensor and wrap it around the cable insulation core once; S2: Pass the measuring line through the circular hole on the position sensor again and continue to pull it horizontally until it is fixed to the first fixing device. At this time, the position sensor is located directly below the circular cross-section of the cable, and the position sensor is kept rolling on the outer surface of the cable during the cable production process.

10. The method for monitoring the outer diameter of cable insulation cores as described in claim 9, characterized in that, In step S1, the measuring wire is wound clockwise around the cable insulation core once.

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