A metal layer embedded high gradient insulator and a preparation method thereof

Abstract

This invention relates to an insulating device and its manufacturing method. To address the problem that existing high-gradient insulator manufacturing methods often result in insufficient withstand voltage stability and potential safety hazards, this invention provides a metal-layer embedded high-gradient insulator and its manufacturing method. The metal-layer embedded high-gradient insulator provided by this invention comprises X insulating sheets and (X-1) metal sheets arranged coaxially alternately from bottom to top, where X ≥ 3; the peripheral outer edge dimension of each metal sheet is smaller than the peripheral outer edge dimension of the insulating sheet; the thickness δ of each insulating sheet... p With respect to the thickness δ of the metal sheet m The ratio δ r Satisfy: 1 ​​< δ r ≤10; the horizontal projected distance d between the outer perimeter of the metal sheet and the outer perimeter of the insulating sheet. h Satisfies: 0.1mm≤d h ≤10mm. This invention also provides two methods for preparing the above-mentioned high-gradient insulators with embedded metal layers, both of which can further improve the flashover voltage and withstand voltage stability of the insulators.

Description

Technical Field

[0001] This invention relates to an insulating device and its preparation method, specifically to a high-gradient insulator with an embedded metal layer and its preparation method. Background Technology

[0002] In the field of vacuum insulation, both vacuum and the vacuum insulating medium can withstand high voltages. However, at their interface, applying an extremely low voltage can trigger surface breakdown discharge, a phenomenon known as vacuum surface flashover. The presence of vacuum surface flashover significantly reduces the overall withstand voltage level of the vacuum insulation system, severely impacting its operating efficiency and stability. Current technologies typically use increasing insulator size to improve withstand voltage, but this increases the volume and complexity of the vacuum insulation system. As devices evolve towards miniaturization and integration, only by improving the flashover withstand voltage per unit distance between insulators can current development requirements be met.

[0003] Traditional high-gradient insulator manufacturing methods generally involve two steps: hot pressing of the metal and insulation layers and machining to form the insulator. During machining, gaps easily form between the metal and insulation layers due to their different coefficients of thermal expansion. Furthermore, metal particles broken during machining can easily embed into the insulation layer, which are difficult to remove during subsequent polishing. These particles remain in the insulation layer, forming electric field enhancement points that increase electron emission intensity and induce flashover. Additionally, exposed metal edges on the insulator surface, being sharp, also easily form electric field enhancement points, inducing flashover and reducing flashover voltage. These adverse factors, especially the random dispersion and uneven particle size of the metal particles generated during machining, result in significant differences in the surface condition of the manufactured insulators, severely reducing their withstand voltage stability and posing a significant safety hazard during use. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing high-gradient insulator preparation methods easily lead to insufficient withstand voltage stability and safety hazards, and to provide a metal-layer embedded high-gradient insulator and its preparation method.

[0005] To achieve the above objectives, the technical solution provided by this invention is:

[0006] A high-gradient insulator with an embedded metal layer, characterized by the following features:

[0007] It comprises X insulating sheets and (X-1) metal sheets arranged coaxially alternately from bottom to top, where X ≥ 3; the outer perimeter of each metal sheet is smaller than the outer perimeter of each insulating sheet; the thickness of each insulating sheet is δ. p With respect to the thickness δ of the metal sheet m The ratio δr Satisfy: 1 ​​< δ r ≤10; the horizontal projected distance d between the outer perimeter of the metal sheet and the outer perimeter of the insulating sheet. h Satisfy: 0.1mm≤d h ≤10mm.

[0008] Furthermore, the outer edges of the X insulating sheets are circular and have the same outer diameter, and the outer edges of the (X-1) metal sheets are also circular and have the same outer diameter.

[0009] Furthermore, each of the insulating sheets is made of plexiglass, cross-linked polystyrene, epoxy resin, nylon, or polyimide, and each of the metal sheets is made of copper, aluminum, or stainless steel.

[0010] Furthermore, the thickness δ of the insulating sheet p With respect to the thickness δ of the metal sheet m The ratio δ r Satisfy: 6 < δ r ≤10; the horizontal projected distance d between the outer perimeter of the metal sheet and the outer perimeter of the insulating sheet. h Satisfy: 2mm≤d h ≤6mm.

[0011] Furthermore, the thickness δ of the insulating sheet p With respect to the thickness δ of the metal sheet m The ratio δ r Satisfy: δ r =10; the horizontal projected distance d between the outer perimeter of the metal sheet and the outer perimeter of the insulating sheet. h Satisfy: d h =2mm.

[0012] Meanwhile, the present invention also provides a method for preparing the above-mentioned metal-layer embedded high-gradient insulator, which is characterized by including the following steps:

[0013] Step 1: Prepare X insulating sheets and (X-1) metal sheets. Prepare a mold that matches the outer edge size of the largest insulating sheet among the X insulating sheets. The mold is cylindrical.

[0014] Step 2: Using a laser, contour lines matching the outer edge dimensions of the metal sheet are machined at the center of the upper and lower surfaces of (X-2) insulating sheets, the lower surface of one insulating sheet and the upper surface of the other insulating sheet, respectively;

[0015] Step 3: Alternately paste X insulating sheets and (X-1) metal sheets in sequence, ensuring that the outer edges of the metal sheets are positioned on the outline, and then place them into the mold;

[0016] Step 4: Apply an axial pressure F1 to the mold for a duration of t1 to ensure that the X insulating sheets are fully bonded to the (X-1) metal sheets;

[0017] Step 5: Disassemble the mold to obtain a metal-layer embedded high-gradient insulator, thus completing the preparation.

[0018] Furthermore, step two specifically involves:

[0019] Using a CO2 laser, ultraviolet laser, or fiber laser, contour lines matching the outer edge dimensions of the metal sheet are machined at the center of the upper and lower surfaces of (X-2) insulating sheets, the lower surface of one insulating sheet, and the upper surface of the other insulating sheet. The depth of the contour lines does not exceed 0.02 mm.

[0020] Furthermore, the present invention also provides another method for preparing the above-mentioned metal layer embedded high gradient insulator, which is characterized by including the following steps:

[0021] Step 1: Preparation of insulator blanks

[0022] Prepare X thin layers of insulating material and (X-1) thin layers of metal, process them into square pieces of the same size, and use a glass plate as a base to alternately paste the X thin layers of insulating material and (X-1) thin layers of metal in sequence, with the outer edges of the edges being consistent, and hold them under the action of axial pressure F2 for a time t2, and then obtain the insulator blank.

[0023] Step 2: Process the insulator blank into an insulator matrix.

[0024] The insulator blank obtained in step one is processed into a columnar body of the required shape, and then its sides are sanded clean with sandpaper.

[0025] Step 3: Select a suitable etchant capable of corroding the metal material used in the metal thin layer in Step 1, and perform an etching operation for a duration of t4 to remove metal shavings from the surface of the insulator substrate obtained in Step 2. Ensure that the outer edge of the metal thin layer is lower than the outer edge of the insulating material thin layer, and the horizontal projection distance d between the outer edges of the metal thin layer and the outer edges of the insulating material thin layer is... h Satisfy: 0.1mm≤d h The thickness is ≤10mm, thus obtaining a metal-layer embedded high-gradient insulator consisting of X insulating sheets and (X-1) metal sheets arranged coaxially from bottom to top; then it is dried to complete the preparation.

[0026] Furthermore, step three specifically involves:

[0027] A 5wt%~60wt% nitric acid, hydrochloric acid, or sulfuric acid solution capable of corroding the metal material used in step one is selected. Under ultrasonic assistance, a corrosion operation is performed for t4 to remove metal shavings from the surface of the insulator substrate obtained in step two. The outer edge of the metal thin layer is lower than the outer edge of the insulating material thin layer. The horizontal projection distance d between the outer edges of the metal thin layer and the outer edges of the insulating material thin layer is... h Satisfy: 0.1mm≤d h ≤10mm, thus obtaining a metal-layer embedded high-gradient insulator consisting of X insulating sheets and (X-1) metal sheets arranged coaxially from bottom to top; clean it thoroughly, and then dry it for t3 time to complete the preparation.

[0028] Furthermore, in step three, the concentration of the nitric acid, hydrochloric acid, or sulfuric acid is 5wt% to 60wt%.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The metal-layer embedded high-gradient insulator provided by this invention has multiple metal sheets embedded inside multiple insulating sheets, forming a metal layer. The embedded metal sheets transform a single thick insulator into a series structure of multiple thin insulators. It possesses the function of a uniform electric field in the metal layer of a traditional high-gradient insulation structure, and can prevent flashover discharge from ablating the metal layer and forming metal debris, thereby eliminating electric field distortion caused by metal debris and improving the withstand voltage stability of the insulator. The size of the metal sheets is smaller than the size of the insulating sheets, and the edges of the embedded metal sheets are inside the insulating matrix, which can effectively suppress the electric field enhancement effect caused by the edge of the metal layer on the surface of the insulator; at the same time, it can effectively block the metal layer from emitting electrons to the surface of the insulator.

[0031] 2. The metal-layer embedded high-gradient insulator provided by the present invention has a groove structure formed by the metal layer embedded between the insulation layers. This groove structure can hinder the secondary electron multiplication on the surface of the insulation material, suppress the development of flashover, and is more conducive to improving the flashover voltage of the insulator.

[0032] 3. This invention provides two methods for preparing high-gradient insulators with embedded metal layers. The first method does not generate metal shavings, and the second method can effectively eliminate the generated metal shavings. Both methods prevent metal shavings from enhancing the electric field on the surface of the insulator, thereby further improving the flashover voltage and withstand voltage stability of the insulator. The first method prepares the high-gradient insulator by bonding with a laminating adhesive, which is different from the traditional hot-press bonding of polymer insulating materials and metal layers. This method can utilize inorganic insulating materials such as ceramics. If a high-temperature resistant adhesive is used, the operating temperature of the high-gradient insulator can be significantly increased. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a first embodiment of the metal-layer embedded high-gradient insulator of the present invention;

[0034] Figure 2 for Figure 1 View from direction A;

[0035] Figure 3 This is a flowchart illustrating the preparation method of the metal-layer embedded high-gradient insulator of the present invention, Example 1.

[0036] Figure 4 This is a flowchart illustrating the preparation method of the metal-layer embedded high-gradient insulator of the present invention, Example 2.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1-Insulating sheet, 2-Metal sheet, 3-Mold. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1:

[0041] A type of high-gradient insulator with embedded metal layer, see [link to relevant documentation]. Figure 1 and Figure 2 It includes five circular organic glass insulating sheets 1 and four circular metal sheets 2 arranged coaxially alternately from bottom to top. The metal sheets 2 are copper sheets. The outer diameter of each insulating sheet 1 is the same, and the outer diameter of each metal sheet 2 is the same. The outer perimeter of the metal sheet 2 is smaller than that of the outer perimeter of the insulating sheet 1.

[0042] Embodiment 1 of the present invention also provides a method for preparing the above-mentioned metal-layer embedded high-gradient insulator, see [link to documentation]. Figure 3 This includes the following steps:

[0043] Step 1: Prepare five insulating sheets 1 and four metal sheets 2 of the same size, and prepare the base radius d. M A cylindrical mold 3 with a thickness of 30mm; wherein the thickness of each insulating sheet 1 is δ p =1mm, all are circular in shape, diameter d p =30mm, all made of acrylic glass; each metal sheet has a thickness of δ. m =0.1mm, all are circular in shape, diameter d m =28mm, all materials are copper;

[0044] Step 2: Using a CO2 laser, contour lines matching the outer edge dimensions of the metal sheet are machined at the center of the upper and lower surfaces of the three insulating sheets, the lower surface of one insulating sheet, and the upper surface of the other insulating sheet. The contour diameter dg =28mm, contour line depth h=0.02mm;

[0045] Step 3: Use adhesive to alternately stick five insulating sheets 1 and four metal sheets 2, positioning the outer edges of the metal sheets 2 on the outline, and then place them into the mold 3;

[0046] Step 4: Apply an axial pressure F1=50N to the mold 3 for a duration of t1=24h to ensure that the five insulating sheets 1 and the four metal sheets 2 are fully bonded together.

[0047] Step 5: Disassemble mold 3 to obtain a metal-layer embedded high-gradient insulator, marked as "1# New Insulator", and complete the preparation.

[0048] Figure 3 The symbols “S1”, “S2”, “S3”, “S4” and “S5” in the diagram represent the operation diagrams for steps one, two, three, four and five, respectively.

[0049] Example 2:

[0050] A metal-layer embedded high-gradient insulator includes nine circular polyimide insulating sheets 1 and eight circular metal sheets 2 arranged alternately from bottom to top. The metal sheets 2 are aluminum sheets. The nine insulating sheets 1 are of the same size, and the eight metal sheets 2 are of the same size. The size of the metal sheets 2 is smaller than the size of the insulating sheets 1. The centroid line connecting the nine insulating sheets 1 and the eight metal sheets 2 is perpendicular to the bottom surface of any insulating sheet 1.

[0051] Embodiment 2 of the present invention also provides a method for preparing the above-mentioned metal-layer embedded high-gradient insulator, see [link to embodiment]. Figure 4 This includes the following steps:

[0052] Step 1: Preparation of insulator blanks

[0053] Prepare nine thin layers of insulating material and eight thin layers of metal, X≥2. Process them into square sheets of the same size. Using a glass plate as a substrate, alternately paste the nine thin layers of insulating material and the eight thin layers of metal with an adhesive film. The thickness of the adhesive film is δ. j =10μm, and held for t2=24h under axial pressure F2=200N, and then the insulator blank is obtained;

[0054] Step 2: Process the insulator blank into an insulator matrix.

[0055] The insulator blank obtained in step one is processed into a cylindrical shape, and then its sides are cleaned with sandpaper.

[0056] Step 3: Select 10wt% hydrochloric acid and perform an ultrasonic-assisted etching process for 30 minutes (t4 = 30 minutes) to remove metal shavings from the surface of the insulator obtained in Step 2. Ensure that the outer edge of the metal thin layer is lower than the outer edge of the insulating material thin layer. The horizontal projection distance d between the outer edges of the metal thin layer and the insulating material thin layer is... h =1.5mm; thus, a metal layer embedded high gradient insulator is obtained, which consists of nine insulating sheets 1 and eight metal sheets 2 arranged coaxially from bottom to top; it is cleaned with deionized water and then placed in an oven to dry for t3=12h, and marked as "2# new insulator" to complete the preparation.

[0057] The corrosive agent in step three can also be a strong acid such as nitric acid or sulfuric acid. When the material of metal sheet 2 is copper or stainless steel, nitric acid can be used for corrosion; when the material of metal sheet 2 is aluminum, hydrochloric acid or sulfuric acid can be used for corrosion.

[0058] Figure 4 The symbols “S1”, “S2”, and “S3” in the diagram represent the operation diagrams for steps one, two, and three, respectively.

[0059] The "1# new insulator" and "2# new insulator" prepared in Examples 1 and 2, along with existing insulators of the same geometric dimensions and insulating matrix material, were subjected to vacuum flashover voltage tests using a vacuum surface flashover characteristic test bench with a pulse voltage width of 500 ns. The flashover voltage test results are shown in Table 1.

[0060] Table 1. Insulator flashover voltage test results

[0061]

[0062] As shown in Table 1, the vacuum flashover voltage of the new insulator is 60-80% higher than that of the existing insulator.

Claims

1. A method for preparing a high-gradient insulator with an embedded metal layer, wherein the high-gradient insulator with an embedded metal layer comprises X insulating sheets (1) and (X-1) metal sheets (2) arranged coaxially alternately from bottom to top, where X ≥ 3; the outer perimeter of the metal sheet (2) is smaller than the outer perimeter of the insulating sheet (1); the thickness δ of the insulating sheet (1) is... p The thickness δ of the metal sheet (2) m The ratio δ r Satisfy: δ r =10; the horizontal projection distance d between the outer periphery of the metal sheet (2) and the outer periphery of the insulating sheet (1) is 10. h Satisfy: d h =2mm; the outer periphery of the X insulating sheets (1) is circular and their outer diameter is the same; the outer periphery of the (X-1) metal sheets (2) is circular and their outer diameter is the same; each insulating sheet (1) is made of plexiglass, cross-linked polystyrene, epoxy resin, nylon or polyimide, and each metal sheet (2) is made of copper, aluminum or stainless steel; characterized in that, Includes the following steps: Step 1: Prepare X insulating sheets (1) and (X-1) metal sheets (2), and prepare a mold (3) that matches the outer perimeter dimensions of the X insulating sheets (1). The mold (3) is cylindrical. Step 2: Using a laser, contour lines matching the outer edge dimensions of the metal sheet (2) are machined on the upper and lower surfaces of (X-2) insulating sheets (1), the lower surface of one insulating sheet (1) and the upper surface of the other insulating sheet (1) to be used for positioning. Step 3: Paste X insulating sheets (1) and (X-1) metal sheets (2) alternately in sequence, and position the outer edge of the metal sheet (2) on the outline line, and then put it into the mold (3); Step 4: Apply an axial pressure F1 to the mold (3) for a duration of t1 to ensure that the X insulating sheets (1) and (X-1) metal sheets (2) are fully bonded together; Step 5: Disassemble the mold (3) to obtain a metal-layer embedded high-gradient insulator, thus completing the preparation.

2. The method for preparing a high-gradient insulator with an embedded metal layer according to claim 1, characterized in that, Step two is as follows: Using a CO2 laser, ultraviolet laser, or fiber laser, contour lines matching the outer edge dimensions of the metal sheet (2) are machined at the center of the upper and lower surfaces of the (X-2) insulating sheets (1), the lower surface of one insulating sheet (1), and the upper surface of the other insulating sheet (1). The depth of the contour lines does not exceed 0.02 mm.

3. A method for preparing a high-gradient insulator with an embedded metal layer, wherein the high-gradient insulator with an embedded metal layer comprises X insulating sheets (1) and (X-1) metal sheets (2) arranged coaxially alternately from bottom to top, where X ≥ 3; the outer perimeter of the metal sheet (2) is smaller than the outer perimeter of the insulating sheet (1); the thickness δ of the insulating sheet (1) is... p The thickness δ of the metal sheet (2) m The ratio δ r Satisfy: δ r =10; the horizontal projection distance d between the outer periphery of the metal sheet (2) and the outer periphery of the insulating sheet (1) is 10. h Satisfy: d h =2mm; the outer periphery of the X insulating sheets (1) is circular and their outer diameter is the same; the outer periphery of the (X-1) metal sheets (2) is circular and their outer diameter is the same; each insulating sheet (1) is made of plexiglass, cross-linked polystyrene, epoxy resin, nylon or polyimide, and each metal sheet (2) is made of copper, aluminum or stainless steel; characterized in that, Includes the following steps: Step 1: Preparation of insulator blanks Prepare X thin layers of insulating material and (X-1) thin layers of metal, process them into square pieces of the same size, and use a glass plate as a base to alternately paste the X thin layers of insulating material and (X-1) thin layers of metal in sequence, with the outer edges of the edges being consistent, and hold them under the action of axial pressure F2 for a time t2, and then obtain the insulator blank. Step 2: Process the insulator blank into an insulator matrix. The insulator blank obtained in step one is processed into a columnar body of the required shape, and then its sides are sanded clean with sandpaper. Step 3: Select a suitable etchant that can etch the metal material used in the metal thin layer in Step 1, and perform an etching operation for a duration of t4 to remove the metal shavings on the surface of the insulator substrate obtained in Step 2, and make the outer edge of the metal thin layer lower than the outer edge of the insulating material thin layer, thereby obtaining a metal layer embedded high gradient insulator with X insulating sheets (1) and (X-1) metal sheets (2) arranged coaxially from bottom to top; then dry it to complete the preparation.

4. The method for preparing a high-gradient insulator with an embedded metal layer according to claim 3, characterized in that, Step three specifically involves: Select nitric acid, hydrochloric acid or sulfuric acid with a concentration of 5wt%~60wt% that can corrode the metal material used in the metal thin layer in step one. Under ultrasonic assistance, perform a corrosion operation for a duration of t4 to remove metal shavings from the surface of the insulator substrate obtained in step two, and make the outer edge of the metal thin layer lower than the outer edge of the insulating material thin layer, thereby obtaining a metal layer embedded high gradient insulator with X insulating sheets (1) and (X-1) metal sheets (2) arranged coaxially from bottom to top; clean it, and then dry it for a duration of t3 to complete the preparation.

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