Superconducting semi-rigid cable made of high purity aluminum and method for making same

Abstract

The application relates to the technical field of cable preparation, in particular to a superconducting semi-rigid cable using high-purity aluminum and a preparation method thereof. The method comprises the following steps: using high-purity aluminum as an inner conductor, and pretreating the inner conductor; using a pusher to coat a PTFE mixture on the surface of the pretreated inner conductor at normal temperature to obtain a normal-temperature pusher core wire; winding the qualified normal-temperature pusher core wire on a cable reel and then placing the cable reel in a vacuum high-temperature furnace to perform vacuum sintering, so as to obtain an inner conductor wrapped with an insulation layer; and passing the inner conductor wrapped with the insulation layer into a pure aluminum outer conductor pipe which has been processed, and coating PTFE on the outer conductor to form an outer protective sleeve. The application can improve the performance stability of the superconducting semi-rigid cable preparation.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing technology, and in particular to a superconducting semi-rigid cable made of high-purity aluminum and its manufacturing method. Background Technology

[0002] Superconducting semi-rigid coaxial cables are excellent cables with superconducting properties. However, problems such as uneven insulation layer diameter and large insulation layer roughness exist during the manufacturing process, leading to excessive signal attenuation and a high risk of insulation breakdown. Therefore, how to improve the performance stability of superconducting semi-rigid cables is an urgent problem to be solved by those skilled in the art.

[0003] Chinese Patent Publication No. CN112037973A discloses a method for preparing an environmentally friendly insulated cable and the cable thereof. The method includes: drawing a conductor core to a specified diameter; wrapping an insulation layer and a shielding layer around the outside of the conductor core to form a conductor; winding multiple conductors around a support wire to form a composite conductor; applying adhesive to the outside of the composite conductor; connecting multiple support tubes and the composite conductor; installing a pressure-resistant sheet between the support tubes; applying hot melt adhesive to the outside of the pressure-resistant sheet; and wrapping a protective layer around the hot melt adhesive. However, the above solution has the following problem: potential defects in the insulation layer covering the inner conductor surface are not sufficiently detected and eliminated, resulting in poor stability of the superconducting semi-rigid cable. Summary of the Invention

[0004] Therefore, the present invention provides a superconducting semi-rigid cable made of high-purity aluminum and its preparation method, in order to overcome the problem in the prior art that the potential defects of the inner conductor surface covering insulation layer are not fully detected and eliminated, resulting in poor stability of the superconducting semi-rigid cable.

[0005] To achieve the above objectives, the present invention provides a method for preparing a superconducting semi-rigid cable using high-purity aluminum, comprising:

[0006] High-purity aluminum is used as the inner conductor, and the inner conductor is pretreated.

[0007] At room temperature, a PTFE mixture is coated onto the surface of a pretreated inner conductor using an extrusion machine to obtain room temperature extruded core wire;

[0008] Abnormal core wire segments are determined based on diameter uniformity, diameter deviation, or roughness anomaly.

[0009] The extreme values ​​of the evaluation are determined based on the abnormal evaluation values ​​corresponding to each abnormal segment. Based on the extreme values ​​of the evaluation, it is determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency, or a secondary determination is made based on the degree of abnormal rise.

[0010] If there is an abnormal tendency in the room temperature extruded core wire produced in the current monitoring cycle, the traction speed or extrusion pressure for the next monitoring cycle will be adjusted according to the degree of abnormality.

[0011] After the qualified room temperature extruded core wire is wound onto the cable reel, it is placed in a vacuum high temperature furnace for vacuum sintering to obtain an inner conductor wrapped with an insulation layer.

[0012] An inner conductor with an insulating layer is inserted into a finished pure aluminum outer conductor tube, and PTFE is wrapped around the outer conductor to form an outer protective sleeve.

[0013] Furthermore, abnormal core wire segments are determined based on diameter uniformity, diameter deviation, or roughness anomaly, including:

[0014] If the diameter uniformity is greater than or equal to the preset diameter uniformity, then the abnormal core wire segment is determined according to the roughness anomaly.

[0015] If the diameter uniformity is less than the preset diameter uniformity, the abnormal core wire segment is determined based on the diameter deviation value.

[0016] Furthermore, the method for confirming the roughness anomaly includes:

[0017] If the profile fluctuation is greater than or equal to the preset profile fluctuation, the roughness anomaly is determined based on the profile fluctuation.

[0018] If the profile fluctuation is less than the preset profile fluctuation, the roughness anomaly is determined based on the axial offset.

[0019] Furthermore, if the evaluation extreme value is greater than or equal to the preset evaluation extreme value, it is directly determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency.

[0020] If the evaluation extreme value is less than the preset evaluation extreme value, a second judgment is made based on the abnormal rise rate.

[0021] In the secondary judgment, if the abnormal rise comparison degree is greater than or equal to the preset abnormal rise comparison degree, it is determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency.

[0022] If the abnormal rise comparison degree is less than the preset abnormal rise comparison degree, it is determined that there is no abnormal tendency in the room temperature extruded core wire produced in the current monitoring cycle.

[0023] Furthermore, the method for confirming the abnormal increase in comparison degree includes:

[0024] The rising core line segment is determined based on the abnormal increase, the abnormal rise degree is determined based on the ratio of the number of rising core line segments to the number of abnormal core line segments, and the abnormal rise comparison degree is determined based on the difference between the abnormal rise degree of the current monitoring period and the adjacent monitoring period.

[0025] The adjacent monitoring period is the monitoring period that is adjacent to the current monitoring period and earlier than the current monitoring period.

[0026] Furthermore, if the abnormality regularity is less than the preset abnormality regularity, the pushing pressure for the next monitoring cycle will be increased.

[0027] The increase in the pushing pressure is positively correlated with the abnormal characterization value.

[0028] Furthermore, if the abnormality regularity is greater than or equal to the preset abnormality regularity, the traction speed for the next monitoring cycle will be reduced.

[0029] The decrease in traction speed is positively correlated with the abnormal characterization value.

[0030] Furthermore, the degree of abnormal regularity is determined based on the degree of distribution regularity and the degree of abnormal fluctuation;

[0031] The degree of abnormal regularity is positively correlated with the degree of distribution regularity, and the degree of abnormal regularity is negatively correlated with the degree of abnormal volatility.

[0032] The present invention also provides a superconducting semi-rigid cable using high-purity aluminum, comprising:

[0033] The device comprises an inner conductor, an insulating layer, an outer conductor, and a protective layer, wherein the insulating layer is wrapped around the outside of the inner conductor, the outer conductor is wrapped around the outside of the insulating layer, and the protective layer is wrapped around the outside of the outer conductor.

[0034] Furthermore, both the inner conductor and the outer conductor are made of high-purity aluminum, and both the insulating layer and the protective layer are made of PTFE.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: In the technical solution of the present invention, the diameter uniformity effectively reflects the overall consistency and stability of the diameter size of each segment of the room temperature extruded core wire. Then, based on the diameter uniformity, abnormal core wire segments are determined according to the diameter deviation value or roughness anomaly. This makes the confirmation of abnormal core wire segments more in line with actual application scenarios, which is conducive to accurately locating the core dimension of core wire quality problems, avoiding the waste of ineffective detection costs, reducing abnormal misjudgment and missed judgment, thereby improving the monitoring efficiency and control accuracy of room temperature extruded core wire production quality, and improving the reliability of core wire.

[0036] Furthermore, this invention effectively reflects the highest level of defect severity of all abnormal core wire segments in room temperature extruded core wire by evaluating extreme values. A primary judgment is then made based on the evaluation extreme values, which is beneficial for quickly identifying global and high-severity quality problems. The abnormal rise rate effectively reflects the deterioration trend of abnormal core wire segments in the current monitoring cycle compared to the adjacent previous cycle. A secondary judgment is then made based on the abnormal rise rate, which is beneficial for accurately capturing the potential risk of continued defect spread even if the evaluation extreme values ​​have not reached the severity threshold, thereby improving the accuracy of quality inspection.

[0037] Furthermore, this invention effectively reflects the distribution regularity and defect stability of abnormal core wire segments in room temperature push-extruded core wire production through anomaly regularity. Based on this anomaly regularity, the traction speed or pushing pressure can be adaptively adjusted, making the adjustment method more suitable for actual application scenarios. This facilitates precise matching of process parameter adjustments and the root causes of quality problems, avoiding production efficiency losses or new defects caused by blind adjustments. It also helps improve the stability and controllability of the room temperature push-extruded core wire production process and reduces the yield rate. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the method for preparing a superconducting semi-rigid cable using high-purity aluminum according to the present invention;

[0039] Figure 2 This is a flowchart of the present invention for determining whether the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency based on the evaluation extreme value, or for making a secondary determination based on the abnormal rise rate.

[0040] Figure 3 This is a flowchart illustrating how the present invention determines the adjustment of traction speed or pushing pressure for the next monitoring cycle based on the degree of abnormal regularity.

[0041] Figure 4 This is a schematic diagram of the structure of the superconducting semi-rigid cable using high-purity aluminum in this invention;

[0042] In the diagram: Inner conductor 1, Insulation layer 2, Outer conductor 3, Protective layer 4. Detailed Implementation

[0043] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0044] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0045] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0046] Furthermore, it should be noted that, in the description of this invention, 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 diametrical 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 invention according to the specific circumstances.

[0047] Please see Figures 1 to 3 As shown, this invention provides a method for preparing a superconducting semi-rigid cable using high-purity aluminum, comprising:

[0048] High-purity aluminum is used as the inner conductor, and the inner conductor is pretreated.

[0049] At room temperature, a PTFE mixture is coated onto the surface of a pretreated inner conductor using an extrusion machine to obtain room temperature extruded core wire;

[0050] Abnormal core wire segments are determined based on diameter uniformity, diameter deviation, or roughness anomaly.

[0051] The extreme values ​​of the evaluation are determined based on the abnormal evaluation values ​​corresponding to each abnormal segment. Based on the extreme values ​​of the evaluation, it is determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency, or a secondary determination is made based on the degree of abnormal rise.

[0052] If there is an abnormal tendency in the room temperature extruded core wire produced in the current monitoring cycle, the traction speed or extrusion pressure for the next monitoring cycle will be adjusted according to the degree of abnormality.

[0053] After the qualified room temperature extruded core wire is wound onto the cable reel, it is placed in a vacuum high temperature furnace for vacuum sintering to obtain an inner conductor wrapped with an insulation layer.

[0054] An inner conductor with an insulating layer is inserted into a finished pure aluminum outer conductor tube, and PTFE is wrapped around the outer conductor to form an outer protective sleeve.

[0055] This invention includes several historical records, each recording at least one instance of the superconducting semi-rigid cable manufacturing process, including diameter uniformity, diameter reference value, roughness anomaly, and diameter deviation. Each historical record also has a corresponding pass / fail mark, indicating whether the superconducting semi-rigid cable manufacturing process meets user requirements. The pass / fail mark can be manually recorded. It is understood that users can determine whether the superconducting semi-rigid cable manufacturing process meets their requirements based on self-defined indicators. These self-defined indicators can be, but are not limited to, the dielectric loss factor of the superconducting semi-rigid cable, which will not be elaborated here. The dielectric loss factor of the superconducting semi-rigid cable is tested using a dielectric loss tester.

[0056] Specifically, the inner conductor has a diameter of 5mm. The pretreatment includes straightening the high-purity aluminum rod using a multi-roll precision straightener, removing residual rolling oil, cutting fluid, and trace metal debris from the surface using ultrasonic cleaning, removing dust and impurities from the inner conductor surface using high-pressure air blowing, and coating the conductor surface with an antioxidant to prevent oxidation. The antioxidant includes, but is not limited to, rosin solution and silane coupling agent. Users can choose according to their actual needs, and there are no specific limitations.

[0057] PTFE particles and extrusion aid are mixed in a low-speed mixer at 60 r / min for 30 minutes to obtain a PTFE mixture. The mass ratio of PTFE particles to extrusion aid in the PTFE mixture is 9:1. The particle size of the PTFE particles is 50-100 μm and the purity is ≥99.9%. The extrusion aid is selected from paraffin oil or white oil with a boiling point of 300-350℃, and the specific selection is not limited.

[0058] The initial parameters of the extruder include: extrusion pressure set to 70 MPa, traction speed set to 2 m / min, screw speed set to 12 rpm, and extrusion speed set to 15 m / min. However, the above values ​​are not limited to these, and those skilled in the art can adjust the above values ​​according to actual needs.

[0059] It is understandable that since the boiling point of the extrusion aid is 300-350℃, and the temperature in the vacuum high-temperature furnace is set to 350℃, the extrusion aid will be fully heated in the vacuum high-temperature furnace, and its temperature will reach its own boiling point range, so that the extrusion aid will vaporize and volatilize from the PTFE mixture.

[0060] The cable reel is made of 304 / 316L stainless steel. The room temperature extruded core wire wound around the cable reel is then placed into a vacuum high temperature furnace, with the temperature set at 350℃ and the heating time set at 30min.

[0061] When coating the outer conductor with PTFE to form an outer protective sleeve, a PTFE mixture is coated onto the surface of the outer conductor using an extruder at room temperature. After coating, the mixture is placed in a vacuum high-temperature furnace for vacuum sintering to form the protective sleeve. The parameters of the extruder are as follows: extrusion pressure is set to 65 MPa, traction speed is 2 m / min, screw speed is set to 14 rpm, extrusion speed is set to 15 m / min, and during vacuum sintering, the temperature is set to 350℃ and the heating time is set to 30 min. However, the above values ​​are not limited to these, and those skilled in the art can adjust the above values ​​according to actual needs.

[0062] The present invention has a continuous cyclic monitoring cycle. The duration of the monitoring cycle can be set according to the user's needs. The greater the user's need for anomaly detection accuracy, the shorter the duration of the monitoring cycle. One possible value for the monitoring cycle is 5 minutes.

[0063] The current monitoring period is recorded as the current monitoring period, and the monitoring period that is adjacent to the current monitoring period but later than the current monitoring period is recorded as the next monitoring period;

[0064] A qualified room temperature extruded core wire is a room temperature extruded core wire whose maximum value among the abnormal assessment values ​​of each core wire segment in each monitoring cycle is less than the preset maximum abnormal assessment value.

[0065] The preset maximum anomaly evaluation value is greater than the preset evaluation extreme value. The user can determine the value of the preset maximum anomaly evaluation value according to the actual application scenario. The greater the user's need for improving the accuracy of the preparation stability of the abnormal core wire segment, the smaller the value of the preset maximum anomaly evaluation value. One preset maximum anomaly evaluation value is provided, which is 0.4.

[0066] Specifically, abnormal core wire segments are determined based on diameter uniformity, diameter deviation, or roughness anomaly, including:

[0067] If the diameter uniformity is greater than or equal to the preset diameter uniformity, then the abnormal core wire segment is determined according to the roughness anomaly.

[0068] If the diameter uniformity is less than the preset diameter uniformity, the abnormal core wire segment is determined based on the diameter deviation value.

[0069] Specifically, the segment of room temperature extruded core wire produced in the current monitoring cycle is evenly divided into n core wire segments of the same length, and a value of n is provided, where n is 20;

[0070] Diameter uniformity = 1 / (standard deviation of the diameter reference value corresponding to each core wire segment + 1). The diameter of a single core wire segment is the diameter of each reference point of that core wire segment. A method for setting reference points is provided, which divides a single core wire segment into n0 equal parts and records each division point as a reference point. A value of n0 is provided, where n0 is 10. The diameter of a single reference point is measured by a laser diameter gauge.

[0071] The preset diameter uniformity value can be determined by the user according to the actual application scenario. The greater the user's demand for improving the accuracy of anomaly monitoring, the larger the preset diameter uniformity value should be. A method for determining the preset diameter uniformity value is provided. The user determines the historical records of abnormal core wire segments based on the diameter deviation value, and the average value of the diameter uniformity corresponding to the historical records that meet the user's needs is recorded as the preset diameter uniformity.

[0072] When determining abnormal core wire segments based on roughness anomaly, core wire segments with roughness anomaly greater than or equal to the preset roughness anomaly are recorded as abnormal core wire segments.

[0073] When determining abnormal core wire segments based on diameter deviation values, core wire segments with diameter deviations greater than or equal to preset diameter deviations are recorded as abnormal core wire segments.

[0074] The diameter deviation of a single core wire segment = the diameter reference value corresponding to that core wire segment - the average diameter reference value of each core wire segment corresponding to the qualified room temperature extruded core wire in the historical records that can meet the user's needs;

[0075] The user can determine the preset roughness anomaly and preset diameter deviation values ​​according to the actual application scenario. The greater the user's need to improve the monitoring accuracy of abnormal core wire segments, the smaller the preset roughness anomaly and preset diameter deviation values ​​should be. A method for determining the preset roughness anomaly and preset diameter deviation values ​​is provided. The average roughness anomaly and the average diameter deviation of each core wire segment corresponding to qualified room temperature extruded core wires in the historical records that meet the user's needs are detected and recorded as the preset roughness anomaly and preset diameter deviation values, respectively.

[0076] Specifically, the methods for confirming the roughness anomaly include:

[0077] If the profile fluctuation is greater than or equal to the preset profile fluctuation, the roughness anomaly is determined based on the profile fluctuation.

[0078] If the profile fluctuation is less than the preset profile fluctuation, the roughness anomaly is determined based on the axial offset.

[0079] Specifically, by using a stylus-type surface roughness tester to scan a core wire segment along its axial direction at a scanning speed of 0.5 mm / s, the axial distance and profile height corresponding to several contour points in the core wire segment can be obtained. The axial distance refers to the distance between the stylus and the initial contact point of the stylus at the start of the core wire segment scanning during the stylus's movement along the core wire's axial direction; the axial movement is the movement in a direction parallel to the central axis of the core wire; the stylus-type surface roughness tester will automatically fit a profile reference line, and the profile height is the height from the contact position between the stylus and the surface being measured to the reference line;

[0080] The standard deviation of the profile height corresponding to each profile point of a single core wire segment is denoted as the profile fluctuation.

[0081] The user can determine the value of the preset profile fluctuation degree according to the actual application scenario. The smaller the value of the preset profile fluctuation degree, the greater the user's need to determine the roughness anomaly degree based on the profile fluctuation degree. A method for determining the value of the preset profile fluctuation degree is provided, which detects the historical records of roughness anomaly degree determined based on the profile fluctuation degree, and records the average value of the profile fluctuation degree corresponding to the historical records that can meet the user's needs as the preset profile fluctuation degree.

[0082] When determining the roughness anomaly based on the profile fluctuation, the roughness anomaly = profile fluctuation / preset profile fluctuation.

[0083] When determining the roughness anomaly based on the axial offset, the roughness anomaly = axial offset / preset axial offset;

[0084] The formula for calculating the axial offset S is: S is in square millimeters, where L is the length of a single core wire segment in mm, z(x) is the profile height corresponding to an axial distance of x in mm, and R is the root mean square deviation of the profile, calculated using the following formula: The unit of R is mm;

[0085] The user can determine the value of the preset axial offset according to the actual application scenario. The greater the user's need for anomaly detection accuracy, the smaller the value of the preset axial offset. One preset axial offset value is provided, which is 0.1 square millimeters.

[0086] Specifically, the profile fluctuation effectively reflects the dispersion of the profile height of the core wire surface. When the profile fluctuation is greater than or equal to the preset profile fluctuation, it indicates that the local undulation of the core wire surface has reached or exceeded the preset judgment standard. Local roughness anomaly is the main factor affecting surface quality. Therefore, the roughness anomaly is determined based on the profile fluctuation.

[0087] When the profile fluctuation is less than the preset profile fluctuation, it means that the local undulation of the core wire surface is within an acceptable range and the local roughness does not constitute a major quality problem. However, it is necessary to further evaluate the overall profile deviation anomaly through axial offset. Therefore, the roughness anomaly is determined based on the axial offset.

[0088] Specifically, if the evaluation extreme value is greater than or equal to the preset evaluation extreme value, it is directly determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency.

[0089] If the evaluation extreme value is less than the preset evaluation extreme value, a second judgment is made based on the abnormal rise rate.

[0090] In the secondary judgment, if the abnormal rise comparison degree is greater than or equal to the preset abnormal rise comparison degree, it is determined that the room temperature extruded core wire produced in the current monitoring cycle has an abnormal tendency.

[0091] If the abnormal rise comparison degree is less than the preset abnormal rise comparison degree, it is determined that there is no abnormal tendency in the room temperature extruded core wire produced in the current monitoring cycle.

[0092] Specifically, the evaluation extreme value is the maximum value among the abnormal evaluation values ​​corresponding to each abnormal paragraph;

[0093] The anomaly assessment value corresponding to a single abnormal segment = roughness anomaly degree / preset roughness anomaly degree × roughness coefficient + diameter deviation degree / preset diameter deviation degree × diameter weight coefficient, where both the roughness weight coefficient and the diameter weight coefficient are 0.5;

[0094] Users can determine the preset evaluation extreme value and preset anomaly rise comparison degree based on the actual application scenario. The greater the user's need to improve the monitoring accuracy of abnormal core wire segments, the smaller the preset evaluation extreme value and preset anomaly rise comparison degree should be. One preset evaluation extreme value and preset anomaly rise comparison degree is provided. The preset evaluation extreme value is 0.3, and the preset anomaly rise comparison degree is the average value of the anomaly rise comparison degree corresponding to each monitoring period in the historical records that can meet the user's needs.

[0095] Specifically, the methods for confirming the abnormal increase in comparison degree include:

[0096] The rising core line segment is determined based on the abnormal increase, the abnormal rise degree is determined based on the ratio of the number of rising core line segments to the number of abnormal core line segments, and the abnormal rise comparison degree is determined based on the difference between the abnormal rise degree of the current monitoring period and the adjacent monitoring period.

[0097] The adjacent monitoring period is the monitoring period that is adjacent to the current monitoring period and earlier than the current monitoring period.

[0098] Specifically, the end of the room temperature extruded core wire produced in the current monitoring cycle that was coated with PTFE earlier is recorded as the initial end. The abnormal core wire segments in the current monitoring cycle are sorted in order of distance from the initial end from near to far. The sorted sequence is recorded as the reference sequence. For a single abnormal core wire segment, if the abnormal increase corresponding to the abnormal core wire segment is greater than 0, the abnormal core wire segment is recorded as the rising core wire segment.

[0099] The abnormal increase corresponding to a single abnormal core line segment = (the abnormal evaluation value corresponding to the abnormal core line segment - the maximum value of the abnormal evaluation values ​​of all abnormal core line segments preceding the abnormal core line segment in the reference sequence) / the average value of the abnormal evaluation values ​​of all abnormal core line segments preceding the abnormal core line segment in the reference sequence; if the abnormal core line segment is the first in the reference sequence, then the abnormal increase of the abnormal core line segment is 0.

[0100] The abnormal rise rate in the current monitoring period = the number of rising core wire segments / the number of abnormal core wire segments;

[0101] Abnormal rise comparison degree = Abnormal rise degree of the current monitoring period - Abnormal rise degree of the monitoring period that is adjacent to and earlier than the current monitoring period. If there is no monitoring period before the current monitoring period, the abnormal rise degree of the current monitoring period is recorded as 0.

[0102] Specifically, if the abnormality regularity is less than the preset abnormality regularity, the pushing pressure for the next monitoring cycle will be increased.

[0103] The increase in the pushing pressure is positively correlated with the abnormal characterization value.

[0104] Specifically, the value of the preset abnormality regularity can be determined by the user according to the actual application scenario. The smaller the value of the preset abnormality regularity, the less the user needs to increase the pushing pressure. A method for determining the value of the preset abnormality regularity is provided, which detects the historical records of increasing the pushing pressure and records the average value of the abnormality regularity corresponding to the historical records that can meet the user's needs as the preset abnormality regularity.

[0105] The increase in extrusion pressure = (abnormal value - preset abnormal value) / preset abnormal value × extrusion pressure threshold; the extrusion pressure threshold is 20 MPa;

[0106] Anomaly characterization value = Evaluation extreme value / Preset evaluation extreme value × Mean coefficient + Anomaly rise comparison degree / Preset anomaly rise comparison degree × Comparison coefficient; The mean coefficient is 0.6, and the comparison coefficient is 0.4;

[0107] The user can determine the value of the preset anomaly characterization value according to the actual application scenario. The greater the user's need for improving the accuracy of cable manufacturing qualification, the smaller the preset anomaly characterization value should be. One preset anomaly characterization value is provided, which is 0.4.

[0108] Specifically, if the abnormality regularity is greater than or equal to the preset abnormality regularity, the traction speed for the next monitoring cycle will be reduced.

[0109] The decrease in traction speed is positively correlated with the abnormal characterization value.

[0110] The decrease in traction speed = (abnormal value - preset abnormal value) / preset abnormal value × traction speed threshold; the traction speed threshold is 0.5 m / min;

[0111] It is understandable that when the abnormality regularity is less than the preset abnormality regularity, due to the poor fluidity of PTFE at room temperature, if the extrusion pressure is too low, it is difficult to form a uniform pressure field throughout the mold cavity. The small protrusions, depressions or pre-treatment defects on the surface of the inner conductor will not be fully filled by PTFE due to insufficient pressure, resulting in defects such as an excessively thin coating layer and local voids. Ultimately, the abnormal core wire segments exhibit low regularity. Therefore, it is necessary to increase and adjust the extrusion pressure to increase the plastic flow capacity of PTFE and improve the preparation effect.

[0112] When the abnormality regularity is greater than or equal to the preset abnormality regularity, the traction speed determines the rhythm of the core wire passing through the mold. If the traction speed is too fast, after PTFE enters the mold, it has not yet fully overcome the flow resistance to evenly adhere to the surface of the inner conductor and fill the mold gap before being pulled out of the mold to complete the shaping. This results in the defects exhibiting periodic characteristics, and the severity of each defect varies very little due to the stability of the equipment parameters. Ultimately, this manifests as a high degree of regularity in the abnormal core wire segments. Therefore, it is necessary to reduce and adjust the traction speed to extend the residence time of PTFE in the mold, providing a sufficient window for its flow and filling, eliminating the periodic defects caused by insufficient molding time, and improving the concentricity and thickness uniformity of the coating layer.

[0113] Specifically, the degree of abnormal regularity is determined based on the degree of distribution regularity and the degree of abnormal fluctuation;

[0114] The degree of abnormal regularity is positively correlated with the degree of distribution regularity, and the degree of abnormal regularity is negatively correlated with the degree of abnormal volatility.

[0115] Specifically, the abnormal regularity is calculated as follows: (distribution regularity / preset distribution regularity) × distribution weight coefficient + (1 - abnormal volatility / preset abnormal volatility) × volatility weight coefficient, where the distribution weight coefficient is 0.7 and the volatility weight coefficient is 0.3.

[0116] Distribution regularity = 1 / (standard deviation of the interval reference value corresponding to each reference anomaly core line segment + 1).

[0117] The reference abnormal core wire segment is the abnormal core wire segment before the last abnormal core wire segment in the reference sequence. For a single abnormal core wire segment, this abnormal core wire segment is recorded as the target abnormal core wire segment. The abnormal core wire segments in the reference sequence that are adjacent to the target abnormal core wire segment and located after the target abnormal core wire segment are recorded as the neighboring abnormal core wire segments. The interval reference value corresponding to the target abnormal core wire segment is the number of core wire segments between the target abnormal core wire segment and the neighboring abnormal core wire segments in the room temperature extruded core wire segments produced in the current monitoring cycle. If the number of abnormal core wire segments in the reference sequence is less than or equal to 2, the distribution regularity is recorded as 0.

[0118] Abnormal volatility is the standard deviation of the abnormal assessment value corresponding to each abnormal core segment. If the number of abnormal core segments is less than or equal to 1, then the abnormal volatility is 0.

[0119] Users can determine the values ​​of preset distribution regularity and preset abnormal fluctuation based on the actual application scenario. The greater the user's need for improving the accuracy of abnormal regularity judgment, the smaller the values ​​of preset distribution regularity and preset abnormal fluctuation. One set of preset distribution regularity and preset abnormal fluctuation is provided, which is the average value of distribution regularity and the average value of abnormal fluctuation corresponding to each monitoring period in the historical records that can meet the user's needs, respectively denoted as preset distribution regularity and preset abnormal fluctuation.

[0120] It should be noted that if abnormal tendencies still exist in the core wire extruded at room temperature after adjusting the traction speed or extrusion pressure, the machine should be stopped for testing.

[0121] Please see Figure 4 As shown, the present invention also provides a superconducting semi-rigid cable made of high-purity aluminum, comprising:

[0122] The inner conductor 1, the insulating layer 2, the outer conductor 3, and the protective layer 4 are provided. The insulating layer 2 is wrapped around the outside of the inner conductor 1, the outer conductor 3 is wrapped around the outside of the insulating layer 2, and the protective layer 4 is wrapped around the outside of the outer conductor 3.

[0123] Specifically, the inner conductor 1 and the outer conductor 3 are both made of high-purity aluminum, and the insulating layer 2 and the protective layer 4 are both made of PTFE.

[0124] High-purity aluminum is aluminum material with a purity of ≥99.99%.

[0125] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for producing a superconducting semi-rigid cable with high purity aluminum, characterized by, The application relates to a high-purity aluminum inner conductor and a method for manufacturing a high-purity aluminum inner conductor. The method comprises the following steps: using high-purity aluminum as the inner conductor and pre-treating the inner conductor; A PTFE mixture is coated on the surface of the pre-treated inner conductor at room temperature by using a pusher to obtain a room-temperature push-pull core wire; The diameter uniformity is used as a judgment criterion, the diameter deviation value or the rough abnormality degree is selected as a judgment parameter, and an abnormal core wire section is identified; if the diameter uniformity is greater than or equal to a preset diameter uniformity, the rough abnormality degree is used to determine the abnormal core wire section; If the diameter uniformity is less than the preset diameter uniformity, the diameter deviation value is used to determine the abnormal core wire section; According to the evaluation extreme value, it is determined that the room-temperature push-pull core wire produced in the current monitoring period has an abnormal tendency, or secondary determination is performed according to the abnormal rising degree; the evaluation extreme value is the maximum value in the abnormal evaluation values corresponding to each abnormal section; According to the abnormal increment, the rising core wire section is determined, and the abnormal rising degree is determined according to the ratio of the number of the rising core wire section to the number of the abnormal core wire section; The abnormal increment corresponding to a single abnormal core wire section = (the abnormal evaluation value corresponding to the abnormal core wire section - the maximum value of the abnormal evaluation values corresponding to each abnormal core wire section located before the abnormal core wire section in the reference sequence) / the average value of the abnormal evaluation values corresponding to each abnormal core wire section located before the abnormal core wire section in the reference sequence; If the room-temperature push-pull core wire produced in the current monitoring period has an abnormal tendency, the traction speed or the push-pull pressure for the next monitoring period is adjusted according to the abnormal regularity degree; The abnormal regularity degree is determined according to the distribution regularity degree and the abnormal fluctuation degree; the distribution regularity degree = 1 / (the standard deviation of the interval reference values corresponding to each reference abnormal core wire section + 1), the reference abnormal core wire section is the abnormal core wire section before the last abnormal core wire section in the reference sequence, for a single abnormal core wire section, the abnormal core wire section is recorded as a target abnormal core wire section, the abnormal core wire section adjacent to the target abnormal core wire section and located after the target abnormal core wire section in the reference sequence is recorded as a neighboring abnormal core wire section, and the interval reference value corresponding to the target abnormal core wire section is the number of the core wire sections between the target abnormal core wire section and the neighboring abnormal core wire section in the room-temperature push-pull core wire section produced in the current monitoring period; The abnormal fluctuation degree is the standard deviation of the abnormal evaluation values corresponding to each abnormal core wire section; The qualified room-temperature push-pull core wire is wound on a cable drum and then placed in a vacuum high-temperature furnace for vacuum sintering to obtain an inner conductor wrapped with an insulation layer; The inner conductor wrapped with the insulation layer is inserted into a pure aluminum outer conductor pipe which has been processed, and PTFE is coated outside the outer conductor to form an outer protective sleeve.

2. The method for manufacturing a superconducting semi-rigid cable with high purity aluminum according to claim 1, characterized in that, The confirmation method of the rough abnormality degree comprises the following steps: If the profile fluctuation degree is greater than or equal to a preset profile fluctuation degree, the rough abnormality degree is determined according to the profile fluctuation degree; If the profile fluctuation degree is less than the preset profile fluctuation degree, the rough abnormality degree is determined according to the axial offset degree.

3. The method of manufacturing a superconducting semi-rigid cable with high purity aluminum according to claim 1, characterized in that, If the evaluation extreme value is greater than or equal to a preset evaluation extreme value, it is directly determined that the room-temperature push-pull core wire produced in the current monitoring period has an abnormal tendency; If the evaluation extreme value is less than the preset evaluation extreme value, secondary determination is performed according to the abnormal rising degree.

4. The method of manufacturing a superconducting semi-rigid cable with high purity aluminum according to claim 1, characterized in that, Abnormal rising ratio degree = abnormal rising degree of current monitoring period - abnormal rising degree corresponding to monitoring period adjacent to and earlier than current monitoring period.

5. The method of manufacturing a superconducting semi-rigid cable with high purity aluminum according to claim 1, characterized in that, Abnormal regularity degree = (distribution regularity degree / preset distribution regularity degree) * distribution weight coefficient + (1 - abnormal fluctuation degree / preset abnormal fluctuation degree) * fluctuation weight coefficient.

6. A superconducting semi-rigid cable using high-purity aluminum, which is applied to the production method of a superconducting semi-rigid cable using high-purity aluminum according to any one of claims 1 to 5, characterized by Comprise: The inner conductor, the insulating layer, the outer conductor and the protective layer, the insulating layer is wrapped in the outer side of the inner conductor, the outer conductor is wrapped in the outer side of the insulating layer, the protective layer is wrapped in the outer side of the outer conductor.

7. The superconducting semi-rigid cable with high purity aluminum of claim 6, wherein, The material of the inner conductor and the outer conductor is high-purity aluminum, and the material of the insulating layer and the protective layer is PTFE.

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