Device for testing dielectric property of insulating material

Abstract

The invention relates to the field of test clamps, in particular to a test device for dielectric properties of an insulating material. The testing device for the dielectric property of the insulating material comprises a first flange, a first cold conduction piece is installed on the first flange, and an elastic piece is arranged in the first cold conduction piece; the second flange is connected to the first flange in a sealing mode, a sealing cavity is defined by the second flange and the first flange, and a second cold conduction piece is installed on the second flange; the elastic piece abuts against the first electrode; the second electrode and the first electrode are oppositely arranged to form a test station; the insulating cold conduction pieces are respectively arranged between the first cold conduction piece and the first electrode and between the second cold conduction piece and the second electrode; the vacuum pipe penetrates through the first flange and communicates with the sealing cavity. According to the testing device for the dielectric property of the insulating material, the problem that a traditional testing device is low in accuracy and reliability is solved; the sample replacement and test preparation time is shortened, and the test efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of test fixtures, and more particularly to a testing device for the dielectric properties of insulating materials. Background Technology

[0002] With the rapid development of modern technology, insulating materials used in cryogenic conditions have shown enormous application potential in many key fields, such as superconducting power transmission, nuclear fusion energy, magnetic levitation trains, quantum computing, and deep space exploration. These extreme cryogenic environments require electrical systems to have extremely high reliability, and the performance of insulating materials is particularly important in such environments. The electrical parameters of insulating materials, such as their dielectric constant and dielectric loss, change significantly under cryogenic conditions; these changes are often nonlinear and difficult to predict. Therefore, evaluating the dielectric properties of insulating materials across different temperature ranges is crucial for optimizing design, developing new materials, and ensuring the normal operation of systems.

[0003] To accurately measure the dielectric properties of insulating materials, specialized test fixtures are required. However, during the cooling process from room temperature to cryogenic temperatures, the insulating material undergoes thermal shrinkage, leading to separation of the clamping contact surfaces, which introduces significant uncertainties. Furthermore, current cryogenic testing environments typically offer limited space to maintain the low temperature, further restricting the size of the test fixtures. Therefore, an ideal test fixture must not only be small and simple in structure but also ensure stable sample clamping, unaffected by changes in ambient temperature.

[0004] The dielectric properties of insulating materials are affected not only by temperature but also by the surrounding gaseous medium. In low-temperature testing, the surrounding gaseous environment, such as vacuum, nitrogen, and helium, can significantly influence the test results. Existing low-temperature testing fixtures often lack a sealing system, making it difficult to control the microscopic atmosphere surrounding the sample, thus resulting in test data that cannot accurately reflect the actual performance of the material under specific operating conditions. Summary of the Invention

[0005] This invention provides a testing device for the dielectric properties of insulating materials, which addresses the shortcomings of low accuracy and reliability in low-temperature insulating material testing in related technologies.

[0006] This invention provides a testing device for the dielectric properties of insulating materials, comprising: A first flange, on which a first cooling guide is installed, and in which an elastic element is provided; The second flange is sealed to the first flange and forms a sealed cavity with the first flange. A second cooling element is installed on the second flange. The first electrode, and the elastic element abuts against the first electrode; The second electrode is positioned opposite to the first electrode to form a test station; Insulating cooling components are respectively disposed between the first cooling component and the first electrode, and between the second cooling component and the second electrode; A vacuum tube is inserted through the first flange and communicates with the sealing cavity.

[0007] According to one embodiment of the present invention, the test station is configured with three stations arranged in parallel and symmetrically. Each test station is provided with a first electrode, a second electrode, an insulating and cooling component, and an elastic component. The leads of the three test stations are respectively connected to different interfaces of the cryogenic aviation port on the second flange.

[0008] According to one embodiment of the present invention, there are three cryogenic aviation ports, and the three cryogenic aviation ports are respectively connected to the leads of the three test stations one by one.

[0009] According to one embodiment of the present invention, the sample contact surfaces of the first electrode and the second electrode are provided with a coating, the first electrode is fitted with a protective electrode, and a gap is formed between the protective electrode and the first electrode.

[0010] According to one embodiment of the present invention, the gap is less than or equal to 0.5 mm.

[0011] According to one embodiment of the present invention, the first cooling component and the second cooling component are made of oxygen-free copper, and the first cooling component is welded to the first flange and the second cooling component is welded to the second flange.

[0012] According to one embodiment of the present invention, the elastic element is in a pre-compressed state, and the elastic force of the elastic element makes the first electrode and the test sample, and the test sample and the second electrode in close contact.

[0013] According to one embodiment of the present invention, the second flange is provided with a raised rib, and the second flange is sealed to the first flange by an indium wire, the indium wire being arranged around the raised rib.

[0014] According to one embodiment of the present invention, the insulating cooling element comprises an aluminum nitride ceramic sheet.

[0015] According to one embodiment of the present invention, both sides of the insulating cold-conducting component are coated with a thermally conductive layer, and the thermally conductive layer fills the gaps between the insulating cold-conducting component and the first cold-conducting component, and between the insulating cold-conducting component and the second cold-conducting component, respectively.

[0016] The testing device for the dielectric properties of insulating materials provided in this embodiment of the invention features symmetrically arranged first and second cooling components that work in conjunction with the insulating cooling component to form a highly efficient solid cooling path. This path rapidly transfers the cold energy from an external cold source to the test sample, enabling the sample to cool quickly and maintain stable temperature across a wide temperature range from room temperature to deep cryogenics. The symmetrical structural design ensures uniform temperature on the upper and lower surfaces of the sample, avoiding the influence of temperature gradients on the dielectric property test results and solving the problem of uneven temperature distribution in traditional testing devices. The combination of a sealed cavity and a vacuum tube allows for flexible switching between vacuum environments and specific gas atmospheres, realistically simulating the actual operating conditions of insulating materials. This overcomes the limitations of traditional open or semi-open testing fixtures in controlling the microscopic atmosphere, making the test data more reflective of the material's actual performance. The reliability of the sealed structure ensures the stability of testing under different atmospheres, preventing gas leakage or pressure fluctuations. The pre-compressed elastic component continuously applies pre-tightening force to the electrodes. In low-temperature environments, this automatically compensates for the thermal shrinkage of the test sample and electrodes, maintaining stable contact pressure and preventing signal interruption or distortion caused by contact surface separation. This solves the problem of poor contact caused by thermal shrinkage at low temperatures, improving the reliability of the test results. The integrated design of all components, with a compact layout of flanges, cooling components, and electrodes, results in a small overall size, making it suitable for installation in confined spaces such as low-temperature Dewars and low-temperature sample chambers. This solves the problem of traditional test clamps being too large to fit low-temperature testing environments, thus enhancing the applicability of the device. Elastic elements replace traditional fastening nuts for electrode pre-tightening, simplifying the clamping structure and eliminating the need for complex locking operations. The detachable design of the sealed cavity facilitates rapid installation and replacement of test samples. Combined with the pre-tightening function of the elastic elements, this significantly reduces sample replacement and test preparation time, improving testing efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic perspective view of one angle of the testing device for the dielectric properties of insulating materials provided by the present invention.

[0019] Figure 2 This is a schematic perspective view of another angle of the testing device for the dielectric properties of insulating materials provided by the present invention.

[0020] Figure 3 This is a schematic perspective view of the internal structure of the testing device for the dielectric properties of insulating materials provided by the present invention.

[0021] Figure 4 This is a schematic cross-sectional view of the internal structure of the testing device for the dielectric properties of insulating materials provided by the present invention.

[0022] Figure 5 This is a schematic perspective view of the first cooling component provided by the present invention.

[0023] Figure label: 100, First flange; 102, First cooling component; 104, Elastic component; 106, Second flange; 108, Second cooling component; 110, First electrode; 112, Second electrode; 114, Insulating cooling component; 116, Vacuum tube; 118, Cryogenic aviation connector. Detailed Implementation

[0024] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0025] like Figures 1 to 5 As shown, the present invention provides a testing device for the dielectric properties of insulating materials, comprising: A first flange 100 is provided, and a first cooling guide 102 is installed on the first flange 100. An elastic element 104 is provided in the first cooling guide 102. The second flange 106 is sealed to the first flange 100 and forms a sealed cavity with the first flange 100. A second cooling element 108 is installed on the second flange 106. The first electrode 110, and the elastic member 104 abuts against the first electrode 110; The second electrode 112 is arranged opposite to the first electrode 110 to form a test station; Insulating cooling elements 114 are respectively disposed between the first cooling element 102 and the first electrode 110, and between the second cooling element 108 and the second electrode 112; A vacuum tube 116 is installed through the first flange 100 and communicates with the sealing cavity.

[0026] According to the embodiments of the present invention, the testing device for the dielectric properties of insulating materials comprises symmetrically arranged first and second cooling elements 108 and insulating cooling element 114, which work together to form an efficient solid cooling path. This path rapidly transfers the cold energy from an external cold source to the test sample, enabling the sample to cool quickly and maintain a stable temperature across a wide temperature range from room temperature to deep cryogenic temperatures. The symmetrical structural design ensures uniform temperature on the upper and lower surfaces of the sample, avoiding the influence of temperature gradients on the dielectric property test results and solving the problem of uneven temperature distribution in traditional testing devices. The combination of the sealed cavity and the vacuum tube 116 allows for flexible switching between vacuum environments and specific gas atmospheres, realistically simulating the actual operating conditions of insulating materials. This overcomes the shortcomings of traditional open or semi-open test fixtures that cannot control the microscopic atmosphere, making the test data more reflective of the actual performance of the material. The reliability of the sealed structure ensures the stability of testing under different atmospheres, preventing gas leakage or pressure fluctuations. The pre-compressed elastic element 104 continuously applies pre-tightening force to the electrode. In low-temperature environments, it can automatically compensate for the thermal shrinkage of the test sample and the electrode, maintaining stable contact pressure and avoiding test signal interruption or distortion caused by contact surface separation. This solves the problem of poor contact caused by thermal shrinkage at low temperatures, improving the reliability of test results. The integrated design of each component, with a compact layout of flanges, cooling components, and electrodes, results in a small overall size, adaptable to the installation requirements of low-temperature Dewars, low-temperature sample chambers, and other confined spaces. This solves the problem of traditional test clamps being too large to fit low-temperature testing environments, enhancing the applicability of the device. The elastic element 104 replaces the traditional fastening nut for electrode pre-tightening, simplifying the clamping structure and eliminating the need for complex locking operations. The detachable design of the sealed cavity facilitates quick installation and replacement of test samples. Combined with the pre-tightening function of the elastic element 104, this significantly shortens sample replacement and test preparation time, improving testing efficiency.

[0027] Please continue reading Figures 1 to 5 The device for testing the dielectric properties of insulating materials provided by this invention achieves accurate testing of the dielectric properties of insulating materials in low-temperature environments through the coordinated design of cooling, sealing, and electrode clamping.

[0028] The first flange 100 is a rigid structure made of material suitable for low-temperature environments, and has mounting holes on its surface for fixing the first cooling conductor 102. The first cooling conductor 102 is made of a high thermal conductivity material and is fixedly connected to the first flange 100. The connection is sealed to prevent cold leakage or gas infiltration. The first cooling conductor 102 has an axial cavity inside, and the elastic element 104 is placed in the cavity. The cavity size is adapted to the elastic element 104 to ensure that the elastic element 104 can expand and contract axially without radial displacement. One end of the elastic element 104 abuts against the bottom of the cooling conductor cavity, and the other end extends out of the cavity and abuts tightly against the first electrode 110, forming a stable preload transmission path.

[0029] The second flange 106 is structurally compatible with the first flange 100, and together they form a sealed cavity, providing a closed testing environment for the test sample. The second cooling conductor 108 is fixedly connected to the second flange 106, and its position corresponds vertically to that of the first cooling conductor 102, forming a symmetrical cooling structure. The structure of the second cooling conductor 108 is identical to that of the first cooling conductor 102, ensuring uniform heat transfer and making the upper and lower surfaces of the test sample have consistent temperatures, thus improving temperature uniformity.

[0030] The first electrode 110 and the second electrode 112 are positioned opposite each other to form a test station, and the test sample is placed between the two electrodes. Insulating heat-conducting components 114 are respectively sandwiched between the first heat-conducting component 102 and the first electrode 110, and between the second heat-conducting component 108 and the second electrode 112. Made of a material with high thermal conductivity and high insulation properties, these components both block electrical conduction between the heat-conducting components and the electrodes and efficiently transfer heat. The contact surfaces of the insulating heat-conducting component 114 with the heat-conducting components and electrodes are flat and smooth, ensuring a tight fit and reducing contact thermal resistance.

[0031] A vacuum tube 116 passes through the first flange 100 and connects to the sealing cavity. A valve can be fitted onto the tube to control its on / off state. The vacuum tube 116 allows for evacuation of the sealing cavity, creating a vacuum testing environment; it can also allow the introduction of specific gases such as nitrogen or helium into the sealing cavity to simulate the actual operating atmosphere of the insulating material. The connection between the vacuum tube 116 and the first flange 100 employs a sealed structure to ensure the sealing performance of the cavity and to maintain the stability of the internal pressure or gas atmosphere.

[0032] The elastic element 104 is in a pre-compressed state, using its own elastic force to push the first electrode 110 towards the second electrode 112, ensuring tight contact between the first electrode 110 and the test sample, and between the test sample and the second electrode 112, without gaps. The elastic force of the elastic element 104 is adapted to the clamping requirements of the test sample, ensuring tight contact without damaging the sample due to excessive pressure. In low-temperature environments, the elastic element 104 can compensate for the thermal contraction of the sample and electrode through its own expansion and contraction, maintaining stable contact pressure and avoiding poor contact caused by thermal contraction.

[0033] According to one embodiment of the present invention, three test stations are provided, which are arranged in parallel and symmetrically. Each test station is provided with a first electrode 110, a second electrode 112, an insulating and cooling conductive component 114, and an elastic component 104. The leads of the three test stations are respectively connected to different interfaces of the cryogenic aviation connector 118 on the second flange 106.

[0034] In one embodiment of the invention, three test stations are arranged symmetrically in parallel along the transverse or longitudinal direction of the device, with uniform spacing and identical structure, ensuring no interference between them. Each test station is independently equipped with a complete set of test components, including a first electrode 110, a second electrode 112, an insulating and cooling conductive component 114, and an elastic component 104, ensuring that each station can independently complete the dielectric property test of the insulating material. The symmetrical layout of the stations ensures that the temperature environment and stress state of each station remain consistent, guaranteeing the uniformity of multi-sample test conditions.

[0035] The first electrode 110 of each test station abuts against the elastic element 104 in the corresponding first cooling conductive element 102. The second electrode 112 is positioned opposite the first electrode 110, forming an independent clamping space for placing the test sample. Insulating cooling conductive elements 114 are respectively disposed between the first cooling conductive element 102 and the first electrode 110, and between the second cooling conductive element 108 and the second electrode 112, achieving both cooling conduction and electrical insulation. The elastic elements 104 at each station are in a pre-compressed state, using elasticity to ensure close contact between the first electrode 110, the test sample, and the second electrode 112, avoiding poor contact caused by thermal shrinkage at low temperatures.

[0036] Each test station's first electrode 110 and second electrode 112 are connected to independent leads. These leads extend along a pre-defined channel inside the second flange 106 and connect to different interfaces of the cryogenic aviation connector 118 on the second flange 106. The lead arrangement avoids tangling and ensures stable signal transmission without affecting the independent operation of each station. The interfaces of the cryogenic aviation connector 118 correspond one-to-one with the leads, facilitating quick connection to external dielectric testing equipment and enabling separate testing or simultaneous monitoring of samples from different stations.

[0037] All three testing stations are located within a sealed cavity formed by the first flange 100 and the second flange 106. A vacuum tube 116 passes through the first flange 100 and communicates with the sealed cavity, allowing for evacuation or the introduction of a specific gas into the entire sealed cavity. This ensures that the samples at all three stations are in the same atmospheric environment, meeting the testing requirements under different atmospheres. The spatial design of the sealed cavity is adapted to the layout of the three stations, ensuring that the samples at each station are cooled uniformly and that the environment remains consistent.

[0038] According to one embodiment of the present invention, three cryogenic aviation connectors 118 are provided, and the three cryogenic aviation connectors 118 are respectively connected to the leads of three test stations one by one.

[0039] In one embodiment of the present invention, three cryogenic aviation connectors 118 are fixedly installed on the second flange 106, evenly distributed along the edge of the flange or a preset installation area, with their positions corresponding one-to-one with the three test stations. The installation method of the aviation connectors is firm and reliable, with good sealing performance, avoiding leakage of vacuum or gas atmosphere in the sealed cavity, while adapting to the usage requirements of the low-temperature testing environment and preventing performance failure at low temperatures.

[0040] Each cryogenic aerospace connector 118 has its internal interface individually connected to the electrode leads of the corresponding test station, forming three independent signal transmission channels. The connection between the leads and the aerospace connector interface is tight with low contact resistance, ensuring stable transmission of dielectric characteristic test signals without signal interference or attenuation. The independent connection method allows testing at each station to be performed individually or simultaneously, improving testing flexibility.

[0041] The external interface specifications of the cryogenic aviation connector 118 are compatible with the connection cables of external dielectric testing equipment, facilitating quick plug-and-play connections and simplifying the testing process. The aviation connector possesses excellent electrical insulation and low-temperature resistance, maintaining stable operation across a wide temperature range from room temperature to deep cryogenics without affecting the accuracy of test signals. The three aviation connectors are clearly labeled, allowing operators to easily distinguish the connection channels for different testing stations and avoid confusion.

[0042] The mounting points of the cryogenic connector 118 and the second flange 106 employ a sealed structure design to ensure the overall sealing performance of the cavity and to avoid affecting the vacuum level or gas atmosphere within the cavity. The installation of the connector does not disrupt the sealed connection between the second flange 106 and the first flange 100, and works in conjunction with the indium wire sealing structure to ensure the sealing reliability of the device under low temperatures and different atmospheres.

[0043] According to one embodiment of the present invention, the sample contact surfaces of the first electrode 110 and the second electrode 112 are provided with a coating, the first electrode 110 is fitted with a protective electrode, and a gap is formed between the protective electrode and the first electrode 110.

[0044] In one embodiment of the present invention, both the surfaces of the first electrode 110 and the second electrode 112 that contact the test sample are coated with a layer. The coating material is a metal material with excellent conductivity and strong chemical stability, which can effectively reduce the contact resistance between the electrode and the sample and reduce the influence of the contact resistance on the dielectric property test results. The coating has a uniform thickness, a smooth surface, and is firmly bonded to the electrode substrate. It is not easily peeled off or oxidized in low-temperature environments or after repeated use.

[0045] A protective electrode is sleeved around the first electrode 110, and the protective electrode is coaxially arranged with the first electrode 110, forming an annular gap between them. The protective electrode is made of the same material as the first electrode 110 or has the same conductivity, and its length is adapted to the first electrode 110, not exceeding the contact range between the first electrode 110 and the sample, and not affecting the contact between the second electrode 112 and the sample. The protective electrode is fixedly installed on the fixed structure of the device, with a stable position, and maintains a fixed gap distance from the first electrode 110.

[0046] The protective electrode is connected to external testing equipment via leads, forming a three-electrode testing structure. This structure effectively shields against external electromagnetic interference, reduces edge effects during testing, and improves the accuracy of dielectric parameter measurements. The annular gap design creates a uniform electric field distribution between the protective electrode and the first electrode 110, ensuring a stable electric field environment for the test sample and meeting the standard requirements for dielectric property testing.

[0047] The installation of the protective electrode does not affect the pressure applied by the elastic element 104 to the first electrode 110, nor does it interfere with the cooling function of the insulating and heat-conducting element 114. The electrode plating and the protective electrode work together to reduce contact resistance and optimize the electric field distribution, making the test results more accurately reflect the dielectric properties of the insulating material, especially suitable for high-precision testing in low-temperature environments.

[0048] According to one embodiment of the present invention, the gap is less than or equal to 0.5 mm.

[0049] In one embodiment of the present invention, the width of the annular gap formed between the protective electrode and the first electrode 110 is less than or equal to 0.5 mm, and the gap size is uniform with no significant deviation along the axial and circumferential directions of the first electrode 110. The size of the gap is ensured through precision machining and assembly. During the overall assembly of the device, the coaxiality of the protective electrode and the first electrode 110 is ensured by the positioning structure, thereby ensuring the uniformity of the gap.

[0050] The outer diameter of the first electrode 110 and the inner diameter of the protective electrode are precisely matched and machined, naturally forming a gap of a preset width after assembly. Positioning steps or limiting structures are provided at both ends of the protective electrode to prevent misalignment during assembly, which could lead to uneven gaps. The interior of the gap is kept clean, free of impurities, burrs, and other factors that could affect the electric field distribution, ensuring the stability of the electric field during testing.

[0051] This gap size effectively suppresses edge effects during testing, concentrating the electric field between the first electrode 110 and the second electrode 112 onto the test sample area, thus reducing the impact of electrode edge electric field distortion on the test results. Simultaneously, the appropriate gap width ensures both the shielding effect of the protective electrodes and prevents short-circuit risks due to excessively small gaps, ensuring the safety and reliability of the testing process.

[0052] The gap size design takes into account the thermal shrinkage characteristics of materials at low temperatures. Within the temperature range from room temperature to deep cryogenics, the difference in thermal shrinkage between the protective electrode and the first electrode 110 will not cause the gap size to exceed the preset range, always remaining within ≤0.5 mm, ensuring measurement accuracy. According to one embodiment of the present invention, the first cooling element 102 and the second cooling element 108 are made of oxygen-free copper, and the first cooling element 102 is welded and fixed to the first flange 100 and the second cooling element 108 is welded and fixed to the second flange 106.

[0053] In one embodiment of the present invention, both the first cooling element 102 and the second cooling element 108 are made of oxygen-free copper. Oxygen-free copper has an extremely high thermal conductivity, which can quickly transfer the cold energy from the external cold source to the electrodes and the test sample, thereby achieving rapid cooling and temperature homogenization of the sample. Oxygen-free copper has stable low-temperature performance and will not become embrittled or experience performance degradation in deep cryogenic environments, ensuring the long-term reliability of the cooling function.

[0054] The first cooling component 102 and the first flange 100, and the second cooling component 108 and the second flange 106 are all fixedly connected by welding. The welded parts are firm and tight, without defects such as pores or cracks, ensuring smooth heat conduction between the cooling components and the flanges without contact thermal resistance. The welding process is adapted to the characteristics of oxygen-free copper and flange materials, avoiding the formation of oxide layers or stress concentrations during welding, which could affect the sealing performance and structural stability of the device.

[0055] The first cooling element 102 has a cavity for mounting the elastic element 104. The cavity size is adapted to the elastic element 104 to ensure that the elastic element 104 can be stably installed and perform its pre-tightening function normally. The structure of the second cooling element 108 corresponds to that of the first cooling element 102. It is connected to the second electrode 112 through an insulating cooling element 114. The contact surface of the cooling element is flat and smooth, which facilitates its fit with the insulating cooling element 114 and improves the cooling efficiency.

[0056] The welding and fixing of the heat-conducting component does not affect the sealing performance of the sealing cavity. The welded part is compatible with the sealing structure of the flange, avoiding cold leakage and gas leakage. The oxygen-free copper heat-conducting component and the insulating heat-conducting component 114 are tightly fitted together. With the use of the heat-conducting layer, the contact thermal resistance is further reduced, enabling the test sample to quickly reach the set temperature and maintain uniformity, ensuring the accuracy of testing in low-temperature environments.

[0057] According to one embodiment of the present invention, the elastic member 104 is in a pre-compressed state, and the elastic force of the elastic member 104 makes the first electrode 110 and the test sample, and the test sample and the second electrode 112 in close contact.

[0058] In one embodiment of the present invention, the elastic element 104 is disposed in the internal cavity of the first cooling element 102. During installation, a preset pressure is applied to the elastic element 104 to put it in a pre-compressed state. The amount of pre-compression is determined according to the thickness of the test sample and the amount of thermal shrinkage at low temperature. One end of the elastic element 104 abuts against the bottom of the cavity of the first cooling element 102, and the other end abuts against the first electrode 110, thereby acting on the first electrode 110 through continuous elastic force.

[0059] The elastic element 104 is made of a material with good elasticity and low-temperature resistance, and can maintain stable elastic properties in a wide temperature range from room temperature to deep low temperature without becoming brittle or permanently deformed. The structural design of the elastic element 104 is adapted to the cavity of the first cooling element 102 and the shape of the first electrode 110, ensuring that the elastic force is uniformly applied to the end face of the first electrode 110, so that the contact pressure between the first electrode 110 and the test sample is evenly distributed.

[0060] After the test sample is placed between the first electrode 110 and the second electrode 112, the pre-compressed elastic element 104 releases its elastic force, pushing the first electrode 110 towards the second electrode 112 until the first electrode 110 and the test sample, and the test sample and the second electrode 112, are in close contact without gaps. When the temperature decreases, the test sample and the electrodes undergo thermal contraction. The elastic element 104 continuously compensates for the contraction through its own elastic deformation, maintaining stable contact pressure and avoiding poor contact.

[0061] The elastic element 104 does not affect the cooling function of the first cooling element 102. The contact between the elastic element 104, the first cooling element 102, and the first electrode 110 does not produce electrical conductivity, ensuring insulation performance. The pre-compression force of the elastic element 104 is moderate, ensuring close contact without causing damage to the test sample or deformation of the electrode due to excessive pressure, thus achieving a balance between contact reliability and sample protection.

[0062] According to one embodiment of the present invention, the second flange 106 is provided with a raised rib, and the second flange 106 is sealed to the first flange 100 by an indium wire, which is arranged around the raised rib.

[0063] In one embodiment of the present invention, the second flange 106 has an annular protrusion on the side facing the first flange 100. The protrusion is arranged along the edge of the second flange 106, and its height and width are precisely designed to form a matching sealing groove structure with the corresponding contact surface of the first flange 100. The surface of the protrusion is flat and smooth, without burrs or unevenness, to ensure a tight fit with the indium wire.

[0064] An indium wire is wound around the raised rib of the second flange 106 to form an annular sealing ring. The diameter of the indium wire is matched with the size of the raised rib and the contact surface gap of the first flange 100. When the first flange 100 and the second flange 106 are sealed together, the indium wire is compressed and deformed, filling the gap between the first flange 100 and the raised rib, forming a reliable sealing structure. The indium wire has good ductility and low-temperature sealing performance, and can maintain its elasticity in low-temperature environments, ensuring that the sealing performance does not degrade.

[0065] The first flange 100 and the second flange 106 are connected and fixed by bolts and other fasteners. The tightening force is applied evenly to cause uniform deformation of the indium wire, ensuring consistent sealing pressure at all points on the sealing surface. The number and distribution of fasteners are adapted to the flange size to ensure a firm flange connection, prevent deformation, and maintain the sealing state of the indium wire.

[0066] The indium wire sealing structure facilitates the assembly and disassembly of the device. When it is necessary to change the test sample, the first flange 100 and the second flange 106 can be separated by loosening the fasteners. After replacing the indium wire or adjusting the sealing condition, it can be quickly resealed, making the operation convenient. The material properties of the indium wire make it reusable, reducing maintenance costs. At the same time, the sealing effect is stable, which can effectively ensure the vacuum environment or specific gas atmosphere in the sealed cavity, meeting the needs of different testing conditions.

[0067] According to one embodiment of the present invention, the insulating cooling element 114 comprises an aluminum nitride ceramic sheet.

[0068] In one embodiment of the present invention, the insulating cooling element 114 is made of aluminum nitride ceramic sheet. This material has a high thermal conductivity and excellent electrical insulation properties, which can rapidly transfer cold energy while blocking the electrical conduction between the first cooling element 102 and the first electrode 110, and between the second cooling element 108 and the second electrode 112. The size of the aluminum nitride ceramic sheet is adapted to the contact surfaces of the first cooling element 102, the second cooling element 108, and the electrodes. It has a uniform thickness and a smooth surface to ensure a tight fit.

[0069] Aluminum nitride ceramic sheets are respectively disposed between the first cooling component 102 and the first electrode 110, and between the second cooling component 108 and the second electrode 112. During installation, it is ensured that the contact surfaces of the ceramic sheets with the cooling components and electrodes are completely in contact without any obvious gaps. The edges of the ceramic sheets do not extend beyond the contact surface of the cooling components or electrodes to avoid affecting the assembly and functionality of other components.

[0070] The cooling energy of the first cooling element 102 and the second cooling element 108 is rapidly transferred to the first electrode 110 and the second electrode 112 through the aluminum nitride ceramic sheet, and then to the test sample, allowing the sample to cool down rapidly and maintain a uniform temperature. At the same time, the electrical insulation properties of the aluminum nitride ceramic sheet prevent short circuits between the cooling elements and the electrodes, ensuring the electrical safety of the testing device and the accuracy of the test signals.

[0071] Aluminum nitride ceramic sheets possess excellent low-temperature performance, exhibiting no embrittlement, cracking, or performance degradation in deep cryogenic environments. They can withstand long-term temperature changes and assembly pressures stably. The ceramic sheets maintain a close fit with the cooling components and electrodes during low-temperature thermal shrinkage, without affecting cooling efficiency or insulation performance, ensuring reliable operation of the testing device across a wide temperature range.

[0072] According to one embodiment of the present invention, both sides of the insulating cold conductive component 114 are coated with a heat conductive layer, and the heat conductive layer fills the gaps between the insulating cold conductive component 114 and the first cold conductive component 102, and between the insulating cold conductive component 114 and the second cold conductive component 108, respectively.

[0073] In one embodiment of the present invention, both sides of the insulating cooling component 114, namely the aluminum nitride ceramic sheet, are uniformly coated with a thermally conductive layer. The thermally conductive layer is made of a material with excellent thermal conductivity, electrical insulation, and low-temperature resistance, such as thermal grease. The coating thickness is uniform to ensure that the tiny gaps between the ceramic sheet and the first cooling component 102, and between the ceramic sheet and the second cooling component 108, are fully filled without any omissions or accumulation.

[0074] The thermally conductive layer fills the gap between the ceramic plate and the cooling component, eliminating the air layer in the gap and significantly reducing the contact thermal resistance. This allows the cooling capacity of the cooling component to be transferred to the ceramic plate more efficiently, and then from the ceramic plate to the electrodes and test samples, improving the cooling rate and temperature uniformity. Simultaneously, the thermally conductive layer possesses electrical insulation properties, not affecting the insulation function of the ceramic plate and preventing electrical continuity between the cooling component and the electrodes.

[0075] The coating process of the thermally conductive layer ensures a strong bond between it and the surface of the ceramic sheet and the cooling component, preventing it from peeling off, curing, or cracking during assembly, disassembly, and in low-temperature environments. The material of the thermally conductive layer is highly compatible with the aluminum nitride ceramic sheet and oxygen-free copper cooling component, does not undergo chemical reactions, and maintains stable thermal conductivity and insulation properties even after long-term use.

[0076] The presence of the thermally conductive layer does not affect the transmission of the preload force of the elastic element 104, nor does it interfere with the sealing performance of the sealing cavity. In low-temperature environments, the thermally conductive layer can adapt to the thermal shrinkage of the material and still maintain the filling state of the gap, continuously playing a role in reducing contact thermal resistance, ensuring that the test sample is in a uniform and stable temperature environment throughout the entire test process, and improving the accuracy and repeatability of the test results.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A testing device for the dielectric properties of insulating materials, characterized in that, include: A first flange, on which a first cooling guide is installed, and in which an elastic element is provided; The second flange is sealed to the first flange and forms a sealed cavity with the first flange. A second cooling element is installed on the second flange. The first electrode, and the elastic element abuts against the first electrode; The second electrode is positioned opposite to the first electrode to form a test station; Insulating cooling components are respectively disposed between the first cooling component and the first electrode, and between the second cooling component and the second electrode; A vacuum tube is inserted through the first flange and communicates with the sealing cavity.

2. The testing apparatus for the dielectric properties of insulating materials according to claim 1, characterized in that, The test station is configured with three stations, which are arranged in parallel and symmetrically. Each test station is equipped with the first electrode, the second electrode, the insulating and cooling component, and the elastic component. The leads of the three test stations are respectively connected to different interfaces of the cryogenic aviation port on the second flange.

3. The testing apparatus for the dielectric properties of insulating materials according to claim 2, characterized in that, The cryogenic aviation connector is configured with three ports, and each of the three cryogenic aviation connectors is connected to a lead wire of one of the three test stations.

4. The testing apparatus for the dielectric properties of insulating materials according to claim 1, characterized in that, The sample contact surfaces of the first electrode and the second electrode are coated with a layer, and a protective electrode is sleeved on the first electrode, with a gap formed between the protective electrode and the first electrode.

5. The testing apparatus for the dielectric properties of insulating materials according to claim 4, characterized in that, The gap is less than or equal to 0.5 mm.

6. The apparatus for testing the dielectric properties of insulating materials according to any one of claims 1 to 5, characterized in that, The first and second cooling components are made of oxygen-free copper. The first cooling component is welded to the first flange and the second cooling component is welded to the second flange.

7. The apparatus for testing the dielectric properties of insulating materials according to any one of claims 1 to 5, characterized in that, The elastic element is in a pre-compressed state, and the elastic force of the elastic element makes the first electrode and the test sample, and the test sample and the second electrode in close contact.

8. The apparatus for testing the dielectric properties of insulating materials according to any one of claims 1 to 5, characterized in that, The second flange is provided with a raised ridge, and the second flange is sealed to the first flange by an indium wire, which is arranged around the raised ridge.

9. The apparatus for testing the dielectric properties of insulating materials according to any one of claims 1 to 5, characterized in that, The insulating and cooling component includes an aluminum nitride ceramic sheet.

10. The apparatus for testing the dielectric properties of insulating materials according to claim 9, characterized in that, Both sides of the insulating cold-conducting component are coated with a thermally conductive layer, which fills the gaps between the insulating cold-conducting component and the first cold-conducting component, and between the insulating cold-conducting component and the second cold-conducting component, respectively.

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