An insulating shield for high arc environments and a method of making the same

Abstract

The application discloses an insulating shielding cover for high electric arc environment and a preparation method thereof, and relates to the technical field of electric arc protection. The insulating shielding cover comprises a long strip-shaped body, a groove matched with a target clamp is arranged on the inner surface of the body, and the body is composed of high electric arc resistant multi-layer functional materials; a shape memory alloy wire is embedded in a deformation memory layer, the shape memory alloy wire generates bending resilience at a set use environment temperature, and can self-adaptively wrap the target clamp; and a locking mechanism is arranged at both ends of the body. The multi-layer functional materials are stacked from outside to inside as follows: an electric arc dissipation layer of a ceramicizable flame-retardant polymer material, a tear-resistant flame-retardant material reinforcing layer, an elastomer material deformation memory layer, and an insulating rubber material inner lining contact layer. The application has good deformation fitting property, high high electric arc resistance, and effectively solves the safety protection problem of low-voltage wire connection operation.

Description

Technical Field

[0001] This invention relates to the field of arc protection technology, and in particular to an insulating shield for high arc environments and its preparation method. Background Technology

[0002] In the operation and maintenance of low-voltage power distribution networks, conductor connections (clamps) are high-risk points for arcing faults. Accidental arcing can pose a serious threat to the safety of workers. Therefore, providing reliable insulation and shielding for workers is a crucial measure to ensure the safety of live-line work.

[0003] Existing protective equipment (such as insulating blankets or ordinary shielding covers) has two intractable problems: First, when using general insulating blankets to cover irregular wire clamps, they do not fit tightly, leaving gaps and making them unstable; second, ordinary shielding covers are difficult to adapt to the shape of wire connections, resulting in poor shielding effect. Even if there are shielding covers with special shapes, their materials are basically ordinary rubber, which is not good at protecting against high electric arcs. When encountering an accidental electric arc, they are easily burned and perforated, and cannot provide effective protection for workers. Summary of the Invention

[0004] To address the problems of insufficient adhesion and inadequate protection against high electric arcs when using insulating blankets to cover irregular wire clamps in existing technologies, this invention provides an insulating shielding cover for high electric arc environments and its preparation method. This cover possesses excellent deformation-fitting capability and strong resistance to high electric arcs, effectively solving the safety protection problem at low-voltage conductor connection points. The specific technical solution is as follows: This application provides an insulating shield for use in high-arc environments, comprising: The shield body is a long strip-shaped shield body, which is made of multi-layer functional material that is resistant to high electric arc, and the inner surface is provided with a groove that matches the shape of the target wire clamp. Shape memory alloy wire, embedded in the multilayer functional material, is pre-programmed to generate bending resilience at a set operating temperature to adaptively wrap around the target wire clamp; and Locking mechanisms are provided at both ends of the shield body; The multilayer functional material is composed of the following layers stacked sequentially: An arc dissipation layer is formed on the outer surface of the shield body and is made of a flame-retardant polymer material that can be ceramicized when exposed to an electric arc. The reinforcing layer, composited on the inner side of the arc dissipation layer, is made of a tear-resistant, flame-retardant material; A deformation memory layer, composited on the inner side of the reinforcing layer, is made of an elastomeric material, and the shape memory alloy wire is embedded in the deformation memory layer; The inner lining contact layer, composited on the inside of the deformation memory layer, is made of insulating rubber material.

[0005] Preferably, the arc dissipation layer is made by mixing silicone rubber and ceramicized silicone rubber microspheres in a certain proportion, wherein the mass percentage of the ceramicized silicone rubber microspheres in the arc dissipation layer is 15%-30%.

[0006] Preferably, the reinforcing layer is formed by impregnating a fiber fabric with flame-retardant silicone; the fiber fabric is aramid cloth or glass fiber cloth.

[0007] Preferably, the shape memory alloy wire is a nickel-titanium alloy wire, and the austenitic phase transformation end temperature Af of the nickel-titanium alloy wire is below 20°C.

[0008] Preferably, the shape memory alloy wires are arranged in a grid-like topology in the deformation memory layer, with a grid spacing of 5mm-15mm.

[0009] Preferably, the diameter of the shape memory alloy wire is 0.2mm-0.5mm.

[0010] Preferably, the depth of the groove is 3mm-5mm, and the thickness of the shield body outside the groove is at least 1.5mm greater than the depth of the groove.

[0011] Preferably, the outer surface of the shield body is provided with reflective strips and laser marking marks for indicating voltage level and arc protection level.

[0012] This application also provides a method for preparing an insulating shield for high arc environments as described above, comprising the following steps: S1: Fix the shape memory alloy wire into the mold according to the predetermined coil shape; S2: Preforms for forming an inner lining contact layer, a deformation memory layer, a reinforcing layer and an arc dissipation layer are sequentially laid or injected into the mold, wherein the preforms for the deformation memory layer cover the shape memory alloy wire; S3: Closed mold, one-time vulcanization molding under temperature of 140℃-180℃ and pressure of 5MPa-15MPa; S4: Open the mold, remove the molded shield body, and install the locking mechanism.

[0013] Preferably, before laying the fiber fabric prepreg of the reinforcing layer, a layer of silane coupling agent modified silicone rubber adhesive slurry is uniformly coated on both sides of the prepreg.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides an insulating shield for high-arc environments. By embedding shape memory alloy wires within the shield body and pre-setting them to maintain a bent shape at room temperature, the shield utilizes the continuous elastic force generated by the alloy wires to automatically and tightly wrap various irregularly shaped wire clamps, significantly reducing the gap between the shield and the clamps. This solves the problems of poor adhesion and easy detachment of traditional insulating blankets. Furthermore, it is composed of four functional materials: the outermost arc dissipation layer uses a material that can be ceramicized upon contact with an electric arc, rapidly forming a hard ceramicized protective layer under the high temperature of the arc, effectively dissipating arc energy and blocking heat conduction; the middle reinforcing layer is made of tear-resistant and flame-retardant material, providing excellent mechanical strength and arc breakdown resistance; the inner contact layer is made of highly insulating rubber, ensuring electrical safety when in contact with live parts. The synergistic effect of these four materials gives the shield excellent arc erosion resistance, tear resistance, and insulation properties.

[0015] 2. An insulating shield for high arc environments according to the present invention achieves rapid positioning and interlocking with the wire clamp by setting a groove on the inner surface of the shield that matches the shape of the wire clamp, and by ensuring sufficient thickness at the bottom of the groove in the thickness design. This ensures that the shield has sufficient electrical insulation strength as a whole, and avoids the problem of sacrificing safety for the sake of fit.

[0016] 3. The method for preparing an insulating shield for high electric arc environments according to the present invention adopts a one-time vulcanization molding process, which molds shape memory alloy wire and multi-layer functional materials in a mold in one step, simplifying the process and ensuring strong interlayer bonding. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0018] Figure 1 This is a schematic diagram of an insulating shield for use in high arc environments, provided in Embodiment 1 of the present invention.

[0019] Figure 2 This is a logical diagram showing the three operating modes of the insulating shield for high arc environments provided in Embodiment 2 of the present invention.

[0020] Figure 3 This is a simplified flowchart illustrating the preparation method of the insulating shield for high arc environments provided in Embodiments 3 and 4 of the present invention.

[0021] The attached diagram is labeled as follows: 100. Insulating shield; 110. Shield body; 111. Arc dissipation layer; 112. Reinforcing layer; 113. Deformation memory layer; 114. Inner lining contact layer; 120. Groove; 130. Shape memory alloy wire; 140. Locking mechanism; 200. Wire clamp. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be understood that, when used in this specification, terms include and encompass the presence of the described feature, integral, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0024] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms "one," "an," and "this" are intended to include the plural forms unless the context clearly indicates otherwise.

[0025] It should also be further understood that the terms used in this specification refer to and include any combination of one or more of the associated listed items, as well as all possible combinations.

[0026] Please refer to the following examples. Figures 1 to 3 .

[0027] Example 1: refer to Figure 1This invention provides an insulating shield 100 for high-arc environments, comprising: a shield body 110, a shape memory alloy wire 130, and a locking mechanism 140. The shield body 110 is elongated and strip-shaped, with quick-locking locking mechanisms 140 at both ends, such as snap-on or Velcro latches, for easy one-handed operation. The inner surface of the shield body 110 has grooves 120 that match the shape of common wire clamps 200 (such as piercing clamps and parallel groove clamps). The depth of the grooves 120 is designed to be within the range of 3-5mm, ensuring a good fit with the clamps 200 while avoiding excessive depth that could affect the overall bending adaptability of the shield 100. The shield body 110 is made of multi-layer functional material composite material that is resistant to high electric arc. Shape memory alloy wire 130 is embedded in the functional material of the shield body 110. The shape memory alloy wire 130 is preset to maintain a bent shape at room temperature to provide continuous radial wrapping force or adhesion force facing the charged body.

[0028] In an embodiment of the present invention, the shield body 110 is composed of four layers of functional materials, mainly including: an arc dissipation layer 111, a reinforcement layer 112, a deformation memory layer 113, and an inner lining contact layer 114. The structure of these four functional materials in the shield body 110 is a system technology solution designed to meet the two core requirements of high arc protection and adaptive bonding. Each functional layer has a clear division of labor and works synergistically.

[0029] The arc dissipation layer 111, located on the outermost layer, is made of a flame-retardant and heat-resistant polymer material that can be ceramicized upon contact with an electric arc, forming a flame-retardant and heat-resistant protective layer. As the first line of defense against electric arc attacks, the core function of the arc dissipation layer 111 is active dissipation rather than direct resistance. More specifically, the arc dissipation layer 111 is made by mixing silicone rubber and ceramicized silicone rubber microspheres in a specific ratio. The ceramicized silicone rubber microspheres have an average particle size of 50μm-150μm, and when exposed to a high-temperature electric arc of 300℃-500℃, they can rapidly sinter into a hard ceramicized shell, effectively isolating heat conduction and arc erosion. In this embodiment, the mass percentage of ceramicized silicone rubber microspheres in the arc dissipation layer is 15%-30%. Preferably, the arc dissipation layer 111 is made by mixing silicone rubber with 25% ceramicized silicone rubber microspheres by mass, and the thickness is designed to be not less than 1.5mm. This layer rapidly ceramizes upon contact with an electric arc, forming a heat-insulating and flame-retardant protective layer. The designed thickness is sufficient to ensure that the surface material undergoes a full and rapid ceramization phase transition upon contact with an electric arc, forming a hard, porous, and heat-insulating ceramic protective layer. This arc dissipation layer 111 effectively dissipates arc energy and blocks heat conduction, thereby protecting the inner layer material. Therefore, an excessively thick arc dissipation layer 111 could lead to internal heat accumulation and material decomposition. In this embodiment, the layer is prepared by mixing 100 parts of methyl vinyl silicone rubber with 30 parts of ceramized silicone rubber microspheres with an average particle size of 80 μm. The ceramization initiation temperature of the ceramized silicone rubber microspheres is 350°C. The final thickness of this layer is approximately 1.5 mm. Upon contact with an electric arc, the microspheres rapidly ceramize, forming a dense heat-insulating barrier.

[0030] A reinforcing layer 112, disposed inside the arc dissipation layer 111, is made of a tear-resistant, flame-retardant material to resist tearing and prevent arc breakdown. The flame-retardant material is formed by impregnating a fiber fabric (e.g., aramid or fiberglass cloth) with flame-retardant silicone. Preferably, the reinforcing layer 112 is made of aramid cloth impregnated with flame-retardant silicone and has a thickness of not less than 1 mm, providing tear resistance and arc breakdown resistance. Aramid cloth itself has extremely high tensile strength and dielectric strength, providing excellent tear resistance to prevent accidental tearing of the shield during installation or use. Even in extreme cases where the outermost layer is ablated, the dense aramid fiber fabric layer impregnated with flame-retardant silicone forms a reliable physical and electrical barrier, effectively preventing arc breakdown. In this embodiment, the reinforcing layer 112 is made of 0.3 mm thick aramid cloth impregnated with flame-retardant silicone to form a prepreg. This layer is approximately 1 mm thick and provides excellent tear resistance and arc breakdown protection.

[0031] The deformation memory layer 113, located inside the reinforcement layer 112, is the core functional layer that gives the shielding cover adaptive fitting performance. This layer is made of a highly elastic material and embeds shape memory alloy wires 130. The shape memory alloy wires 130 are made of nitinol alloy wires, and the austenitic phase transformation end temperature (Af point) of the nitinol alloy wires is below 20°C. The diameter of the shape memory alloy wires 130 is 0.2mm-0.5mm, and they are arranged in a grid-like topological structure in the deformation memory layer, with a grid spacing of 5mm-15mm. Preferably, the deformation memory layer 113 is made of highly elastic silicone rubber with a thickness of not less than 2mm, and the nitinol (NiTi) shape memory alloy wires 130 are pre-embedded therein. The austenitic phase transformation end temperature (Af point) of the alloy wires 130 is set to 15°C (below 20°C). In the deformation memory layer 113, a highly elastic material provides support and cushioning for the alloy wire 130. The alloy wire 130, with its pre-set bent shape, generates a stable rebound force at room temperature, allowing the shielding cover to automatically and tightly wrap around wire clips of different sizes. This solves the problem of poor fit caused by fixed shapes or material creep in traditional shielding covers. In this embodiment, the deformation memory layer 113 is made of highly elastic silicone rubber (Shore A40-50 hardness) with a thickness of approximately 2.5 mm. Multiple 0.3 mm diameter nickel-titanium alloy wires are embedded in this layer in a mesh-like topology (mesh spacing 10 mm). The austenitic phase transformation end temperature Af of the alloy wires is set to 15°C.

[0032] The inner contact layer 114, located inside the deformation memory layer 113, is the ultimate guarantee of electrical safety for the shield. This layer is made of highly insulating, high-purity flame-retardant silicone rubber, with a thickness of approximately 1 mm. As the interface in direct contact with live parts, the inner contact layer 114 must ensure the highest insulation reliability (high dielectric strength) and chemical stability. The approximately 1 mm thick highly insulating flame-retardant rubber meets the relevant safety standards for contact insulation thickness under compression, while maintaining overall flexibility.

[0033] To address the issue that one-time vulcanization (at temperatures as high as 140-180℃) might disrupt the pre-defined memory effect of the nickel-titanium alloy wire, the following key measures were taken during the preparation process in this embodiment: 1) Pre-coating treatment: After fixing the alloy wire in the mold according to the preset bending shape, a layer of polytetrafluoroethylene (PTFE) insulating emulsion with a temperature resistance of over 200℃ is applied to its surface. After drying, an insulating layer of about 5μm thickness is formed. This coating can temporarily block the rapid transfer of heat to the alloy wire in the early stage of vulcanization.

[0034] 2) Secondary aging treatment: After vulcanization is completed and the shielding cover body 110 is removed from the mold, it is placed in an oven at 80°C for 20 minutes and then allowed to cool naturally to room temperature with the furnace. This step aims to eliminate the residual stress generated inside the alloy wire during the high-temperature forming process and to re-stabilize its two-way memory effect at room temperature, ensuring that it can generate a continuous and stable springback wrapping force at room temperature.

[0035] After the above treatment, tests showed that the alloy wire inside the finished shield could generate a radial rebound force of about 0.8 N / cm at 25°C.

[0036] The locking mechanism 140 includes an injection-molded polyoxymethylene (POM) snap-fit ​​head, which is fixed to one end of the shield body 110 by rivets; and a flexible silicone buckle strap, which is fixed to the other end of the body 110. The buckle strap has multiple positioning holes at equal intervals that mate with the snap-fit ​​head. Operators can select appropriate positioning holes to lock the snap-fit ​​head according to the size of the wire clamp.

[0037] Furthermore, the depth of the groove 120 is preferably designed to be approximately 4 mm (within the range of 3 mm to 5 mm). This depth is intended to create a geometric interlock with the protruding parts of the wire clamp (such as bolt heads), enabling rapid positioning and preventing lateral slippage. The total thickness (sum of four layers) of the shield body 110 in the flat area is designed to be no less than 5.5 mm, which means that there is a localized compression thinning zone at the bottom of the groove 120. This design is a carefully calculated trade-off; the groove 120 area prioritizes geometric positioning and stress guidance, and its thinner portion (with a remaining thickness of no less than 1.5 mm) increases material density and creates a tighter interface contact after being compressed by the wire clamp, thus improving local insulation performance. Simultaneously, the reinforcing layer 112 in this area constitutes a crucial protection against breakdown.

[0038] The insulating shield 100 provided in this embodiment of the invention has its main insulation safety bearing area in the large area around the groove 120. These areas maintain a complete standard thickness and constitute the main electrical creepage path and insulation barrier. This design maximizes the fit and ease of installation of the shield while ensuring the overall insulation safety of the shield, thereby avoiding the rigidity and bulkiness caused by excessive thickness.

[0039] In addition, the outer surface of the shield body 110 is also provided with reflective strips and markings formed by laser marking, which are used to indicate the voltage level (such as 0.4kV) and arc protection level, improving visibility and safety in the working environment.

[0040] Example 2: Based on Embodiment 1, this embodiment provides another specific implementation method for material combination and structural optimization to demonstrate the versatility and scalability of the technical solution of the present invention.

[0041] refer to Figure 1 and Figure 2 This embodiment provides an insulating shield 100' for high-arc environments, whose overall structure is the same as that of Embodiment 1, including a long strip-shaped shield body 110, grooves 120 on the inner surface, embedded shape memory alloy wires 130, and locking mechanisms 140 at both ends. The main difference from Embodiment 1 lies in the material selection and specific parameters of each functional layer.

[0042] The arc dissipation layer 111 in this embodiment also uses a material that can be ceramicized by an electric arc, but a different combination of matrix and filler is selected. The matrix is ​​addition-cured liquid silicone rubber (100 parts). The filler consists of 20% by mass of nano-sized ceramic powder (average particle size 500 nm) and 10% by mass of chopped ceramic fibers (0.5-1 mm in length). The functions and effects of this layer include: the synergistic effect of the nano-ceramic powder and chopped fibers, which can more quickly form a three-dimensional ceramic skeleton structure under the action of an electric arc, further improving the structural strength and ablation resistance of the arc dissipation layer. The thickness of this layer is approximately 1.2 mm.

[0043] In another preferred embodiment, the arc dissipation layer is made of methyl vinyl silicone rubber as the matrix, and is compounded with ceramicized silicone rubber microspheres, a reinforcing system, a flame retardant system, and a vulcanization system, with a thickness ≥1.5mm. The raw materials, by weight, are: Base rubber: 100 parts of methyl vinyl silicone rubber, using conventional electrical grade silicone rubber with a vinyl content of 0.16~0.22mol% and a Mooney viscosity of ML(1+4) 25℃ of 40~60, to ensure flexibility and weather resistance after vulcanization; Ceramicized silicone rubber microspheres: 15~30 parts (corresponding to 15%~30% by mass). The core parameters of the microspheres are: particle size D50=5~20μm, ceramicization transition temperature ≥350℃, flexural strength after ceramicization ≥8MPa, oxygen index ≥45%. Commercially available finished products can use hollow ceramicized silicone rubber microspheres coated with organosilicon resin to improve dispersibility and impact resistance. Reinforcing filler: 20-30 parts of fumed silica, with a specific surface area of ​​150-200 m² / g, to ensure the mechanical strength of the matrix; Structure control agent: 2-4 parts hydroxy silicone oil, to prevent structure reversion during the mixing process; Composite flame retardant: 10-15 parts aluminum hydroxide, particle size D50=3-5μm, which synergistically enhances flame retardancy and smoke barrier effects with ceramic microspheres; Vulcanizing agent: 0.8~1.2 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis2,5), with excellent vulcanization temperature matching, suitable for one-time vulcanization molding process.

[0044] Preparation process of arc dissipation layer compound: The compound is prepared by internal mixer. First, methyl vinyl silicone rubber raw rubber is added and plasticized for 3 minutes. Then, hydroxyl silicone oil and fumed silica are added and mixed for 5 minutes to ensure uniform dispersion of fillers. Ceramicized silicone rubber microspheres and aluminum hydroxide are added in sequence and mixed for 8 minutes. Finally, bis(2,5) vulcanizing agent is added and mixed for 2 minutes before discharge. After discharge, the material is passed through a two-roll mill 3 times to produce a sheet with a thickness of 2 mm. The sheet is then left to stand at room temperature for 24 hours to ensure stable performance before vulcanization.

[0045] In this embodiment, the reinforcing layer 112 uses a different fiber fabric. For example, it is formed by impregnating a high-strength, high-modulus polyethylene fiber fabric (e.g., ultra-high molecular weight polyethylene fiber fabric) with flame-retardant polyurethane adhesive. Ultra-high molecular weight polyethylene fiber fabric has a higher specific strength and better flexibility than aramid fabric, providing reliable tear and puncture resistance while further reducing the overall weight and stiffness of the shield, resulting in a more snug fit. The thickness of this layer is approximately 0.8 mm.

[0046] In another preferred embodiment, the reinforcing layer is made of aramid cloth / glass fiber cloth impregnated with flame-retardant silicone, with a thickness ≥1mm. The specific preparation process is as follows: Substrate selection: Aramid cloth is made of plain weave aramid 1414 woven fabric with a basis weight of 100~120g / ㎡ and a tensile strength of ≥2000N / 5cm, ensuring tear resistance and puncture resistance; glass fiber cloth is made of alkali-free electronic grade glass fiber cloth with a basis weight of 80~100g / ㎡, with better insulation performance. Preparation of impregnation solution: Take 100 parts of methyl vinyl silicone rubber, 25 parts of fumed silica, 3 parts of hydroxyl silicone oil, and 1 part of bis 2,5 vulcanizing agent, add them to No. 120 gasoline and stir to dissolve, so as to prepare a flame-retardant silicone impregnation solution with a solid content of 30%. Impregnation and drying process: The aramid / glass fiber cloth is completely immersed in the impregnation solution for 5 minutes to ensure that the adhesive completely wets the fiber gaps; after impregnation, it is removed and dried in two stages in a vertical oven. The first stage is drying at 80°C for 10 minutes to remove the solvent, and the second stage is pre-curing at 120°C for 5 minutes to make a semi-cured prepreg. It is then sealed and stored at room temperature for later use. The gel time of the prepreg is matched with that of the upper and lower rubber layers to ensure a tight interface bond during one-time vulcanization molding.

[0047] This embodiment optimizes the arrangement of the shape memory alloy wire 130 and the elastomer matrix. The elastomer matrix uses thermoplastic polyurethane elastomer (TPU), which has excellent elasticity and processing properties. During the wire arrangement, the shape memory alloy wire 130 (also made of Nitino, Af point 18°C, wire diameter 0.4mm) is arranged with a non-uniform density within the layer. Specifically, in the edge area of ​​the groove 120 expected to correspond to the protruding parts of the wire clamp (such as bolt heads), the alloy wire arrangement density is higher (5mm spacing), while in flat areas it is more sparse (15mm spacing). Compared with silicone rubber, the thermoplastic polyurethane elastomer matrix can provide different support feel for the alloy wire. The non-uniform arrangement of the alloy wire achieves differentiated adaptive wrapping of the wire clamp 200, providing stronger local wrapping force in stress concentration areas to ensure a tight fit; while maintaining flexibility in non-critical areas, resulting in more uniform overall stress and easier installation. The layer thickness is approximately 2.0mm.

[0048] In another preferred embodiment, the deformation memory layer uses high-elasticity methyl vinyl silicone rubber as the matrix, with a thickness ≥2mm. The raw materials, by weight, are: 100 parts of high-elasticity methyl vinyl silicone rubber (vinyl content 0.08~0.12mol%, Mooney viscosity 30~40, elongation at break ≥800%), 15~20 parts of fumed silica, 1~2 parts of hydroxyl silicone oil, and 0.8~1.0 parts of bis(2,5) vulcanizing agent. The mixing process is the same as that of the arc dissipation layer. After the mixed rubber is made, the sheet thickness is 2.5mm, and it is left to stand at room temperature for later use.

[0049] In this embodiment, the inner lining contact layer 114 is made of a composite material. It uses ethylene propylene diene monomer (EPDM) rubber as the matrix and incorporates a small amount (5% by mass) of hexagonal boron nitride micropowder (a thermally conductive filler). EPDM rubber possesses excellent electrical insulation and weather resistance. The addition of hexagonal boron nitride micropowder significantly improves the thermal conductivity of the inner lining contact layer 114 while maintaining high insulation (boron nitride is an excellent insulator). This helps to more quickly conduct and disperse heat from localized hot spots, further enhancing the overall thermal management capability and safety of the shield. The thickness of this layer is approximately 1.0 mm.

[0050] In another preferred embodiment, the inner lining contact layer is made of high-insulation, high-purity flame-retardant silicone rubber with a thickness of 1mm ± 0.2mm. The raw materials, by weight, are: 100 parts of power-grade high-purity methyl vinyl silicone rubber (vinyl content 0.18mol%, volatile matter ≤0.5%, no conductive impurities), 20 parts of fumed silica, 2 parts of hydroxyl silicone oil, 0.5 parts of platinum-based flame retardant, and 1.0 part of bis(2,5) vulcanizing agent. After mixing, the sheet thickness is 1.2mm to ensure that the thickness after vulcanization meets the insulation requirements, and the power frequency breakdown strength is ≥28kV / mm.

[0051] In its fabrication, the shielding cover of this embodiment can be prepared using a one-time vulcanization molding process similar to that of Embodiment 3. The difference lies in the fact that, since the deformation memory layer 113 uses TPU thermoplastic material, it requires compression molding instead of vulcanization molding. That is, the TPU is melted and flowed under heat and pressure to cover the alloy wire, and then cooled and shaped. The specific process parameters are: temperature 180°C, pressure 10MPa, and pressure holding and cooling time 15 minutes.

[0052] Example 3: refer to Figure 3 Embodiment 3 of the present invention discloses a method for preparing an insulating shield as described in Embodiment 1 above, the method comprising the following steps: S1: The pre-coated (PTFE) nickel-titanium alloy shape memory wire 130 is fixed in the mold cavity by positioning pins in the mold according to the predetermined mesh topology and bending shape.

[0053] S2: Lay the preformed material into the mold in sequence: a) First, inject or lay a layer of silicone rubber compound with an inner lining contact layer 114 of about 1 mm thickness into the mold cavity. b) Then, a layer of highly elastic silicone rubber compound with a thickness of about 2.5 mm is laid on the inner lining contact layer 114 to form the deformation memory layer 113, and the shape memory alloy wire 130 fixed in step S1 is completely wrapped therein. c) Next, take a piece of aramid fabric (prepreg of reinforcing layer 112) impregnated with flame-retardant silicone and about 0.3 mm thick, coat both sides of it with a layer of silicone rubber adhesive slurry modified with silane coupling agent, and then lay it flat on the premix of deformation memory layer 113. d) Finally, a layer of silicone rubber compound containing ceramicized silicone rubber microspheres, with a thickness of about 1.5 mm, is laid on the reinforcing layer 112 to form the arc dissipation layer 111.

[0054] S3: Close the mold and perform one-time vulcanization molding under the conditions of temperature 140℃~180℃ and pressure 5MPa~15MPa, with a molding time of 10~30 minutes; In practice, the core process parameters for vulcanization molding can be divided into three adaptable levels, which can be flexibly adjusted according to the material formula and mold size, as follows: S4: After the mold is opened, the shield body 110 is taken out and subjected to secondary aging treatment (80°C, heat preservation for 20 minutes, and cooling with the furnace) according to the method described in Example 1. Then, the buckle head, buckle strap and marking of the locking mechanism 140 are installed.

[0055] When the shielding cover is retrieved, the operator takes it out of storage. Because the embedded shape memory alloy wire 130 maintains a pre-bent shape at room temperature, the shielding cover body 110 naturally bends to match the target clamp 200. The groove 120 of the shielding cover 100 is aligned with the clamp 200 and wrapped around it. Under the continuous elastic force of the shape memory alloy wire 130, the shielding cover body 110 adaptively conforms to the irregular surface of the clamp 200. Finally, the locking mechanisms 140 at both ends are tightened, completing the installation of the shielding cover 100 and putting it into a protective state, providing safety protection for subsequent live-line work.

[0056] Example 4: refer to Figure 3 This embodiment discloses another method for preparing an insulating shield as described in Embodiment 1 or Embodiment 2, aiming to demonstrate the feasibility of different material systems and process parameters. This embodiment takes the preparation of the shield with the structure described in Embodiment 1 as an example, but uses different compound rubber formulations and vulcanization conditions.

[0057] The preparation method includes the following steps: S1: Alloy wire pretreatment and fixing. 0.25mm diameter nickel-titanium alloy wire (Af point 12℃) is woven into a mesh structure with an 8mm spacing, and then subjected to vacuum shaping heat treatment at 500℃ for 30 minutes according to a preset bending shape to memorize the bending shape. The shaped alloy wire mesh is then fixed in the mold cavity using positioning pins within the mold.

[0058] S2: Preparation and laying of preforms for each layer.

[0059] Preparation of Arc Dissipation Layer 111 Compound: Take 100 parts of methyl vinyl silicone rubber, add 35 parts of ceramicized silicone rubber microspheres with an average particle size of 120 μm, 10 parts of fumed silica, and 1.5 parts of vulcanizing agent bis(2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), mix evenly on a two-roll mill, and sheet for later use.

[0060] Preparation of 114 compound for inner lining contact layer: Take 100 parts of high-purity methyl vinyl silicone rubber, add 15 parts of fumed silica and 1.2 parts of vulcanizing agent bis(2,5)5, ​​mix evenly, and sheet for later use.

[0061] The laying sequence includes: a) First lay the inner lining contact layer 114 compound rubber sheet inside the mold; b) Lay a high-elasticity silicone rubber compound sheet on it to form the deformation memory layer 113, and press the alloy wire mesh fixed in step S1 into the layer to ensure that it is completely covered. c) Take a piece of glass fiber cloth (reinforcing layer prepreg) impregnated with flame-retardant silicone and lay it directly on the deformation memory layer 113. In this embodiment, no additional interface adhesive is used. Instead, the flowability of the upper arc dissipation layer 111 compound during vulcanization is utilized to penetrate into the glass fiber cloth to achieve interlayer bonding. d) Finally, lay the arc dissipation layer 111 compounded sheet on the fiberglass cloth.

[0062] S3: Vulcanization molding. Close the mold and feed it into a flat vulcanizing machine. Vulcanization conditions are: temperature 150℃, pressure 8MPa, molding time 30 minutes.

[0063] S4: Post-processing and assembly. Remove the molded shield body 110 from the mold and allow it to cool naturally to room temperature. Because the alloy wire used in this embodiment has a lower Af point (12℃) and has undergone sufficient shaping heat treatment, its memory effect is well maintained after vulcanization at 150℃, thus eliminating the need for secondary aging treatment. Finally, install the locking mechanism 140 and markings.

[0064] Performance Comparison Examples Finally, to fully verify the significant advancements of this invention compared to existing technologies, we conducted a systematic comparative test. The test samples included: Sample A (shielding cover 100 prepared in Example 1 of the present invention): adopts the standard scheme of uniformly arranged alloy wires and ceramic microsphere arc dissipation layer in a grid pattern.

[0065] Sample A2 (the shield 100 prepared in Example 2 of this invention): adopts an optimized scheme of non-uniform alloy wire arrangement and nano-ceramic powder + fiber arc dissipation layer.

[0066] Sample B (Comparative Example 1): Commercially available general-purpose insulating blanket (silicone rubber material, without reinforcement layer and shape memory function).

[0067] Sample C (Comparative Example 2): Commercially available dedicated wire clip shield (made of ordinary rubber, with grooves for the shape of the wire clip, but without multi-layer composite structure and shape memory function).

[0068] The test results are as follows: A 3D optical scanner was used to acquire the 3D contour of the inner surface of each sample after wrapping it with a standard puncture clamp, and the contour was compared with the 3D model of the clamp itself to calculate the average and maximum gaps between the two. The smaller the gap, the tighter the fit.

[0069] Conclusion: The arc resistance time of the sample of this invention far exceeds that of existing products. The ceramic arc dissipation layer plays a key role, verifying its superior performance in resisting high arcs.

[0070] Arc resistance tests were conducted under clean, dry laboratory conditions according to ASTM D495-22 standard. A high-voltage, low-current arc was applied to the sample, and the time from the start of arc application to sample breakdown or the formation of a stable conductive path was recorded. The macroscopic state of the sample after ablation was also observed and recorded. This test was used for preliminary screening and performance comparison of the material of this invention with comparative materials.

[0071] Conclusion: The arc resistance time of the sample of this invention far exceeds that of existing products. The ceramic arc dissipation layer 111 and the reinforcing layer 112 played a key role, verifying its superior performance in resisting high arcs.

[0072] Finally, the overall performance comparison is as follows: In conclusion, the test data above clearly demonstrates that, compared with existing technologies, the insulating shield provided by this invention achieves tight and uniform wrapping of irregular wire clamps by embedding shape memory alloy wires 130, solving the problem of poor fit in traditional tools; through a multi-layer composite structure, particularly the ceramicizable arc dissipation layer 111 and the high-strength reinforcement layer 112, it effectively dissipates and resists high arc energy, significantly improving the safety protection level. Therefore, this invention successfully solves the technical problems raised in the background art and achieves unexpected technical effects, demonstrating significant progress.

[0073] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0074] In particular, the device embodiments are basically similar to the method embodiments, so they are described in a simpler way. For relevant details, please refer to the description of the method embodiments.

[0075] 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 or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the specification of the present invention.

Claims

1. An insulating shield for use in high-arc environments, characterized in that, include: The shield body is a long strip-shaped shield body, which is made of multi-layer functional material that is resistant to high electric arc, and the inner surface is provided with a groove that matches the shape of the target wire clamp. Shape memory alloy wire, embedded in the multilayer functional material, is pre-programmed to generate bending resilience at a set operating temperature to adaptively wrap around the target wire clamp; and Locking mechanisms are provided at both ends of the shield body; The multilayer functional material is composed of the following layers stacked sequentially: An arc dissipation layer is formed on the outer surface of the shield body and is made of a flame-retardant polymer material that can be ceramicized when exposed to an electric arc. The reinforcing layer, composited on the inner side of the arc dissipation layer, is made of a tear-resistant, flame-retardant material; A deformation memory layer, composited on the inner side of the reinforcing layer, is made of an elastomeric material, and the shape memory alloy wire is embedded in the deformation memory layer; The inner lining contact layer, composited on the inside of the deformation memory layer, is made of insulating rubber material.

2. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The arc dissipation layer is made by mixing silicone rubber and ceramicized silicone rubber microspheres in a certain proportion, wherein the mass percentage of the ceramicized silicone rubber microspheres in the arc dissipation layer is 15%-30%.

3. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The reinforcing layer is formed by impregnating a fiber fabric with flame-retardant silicone; the fiber fabric is made of aramid or glass fiber.

4. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The shape memory alloy wire is a nickel-titanium alloy wire, and the austenitic phase transformation end temperature Af of the nickel-titanium alloy wire is below 20°C.

5. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The shape memory alloy wires are arranged in a grid-like topology in the deformation memory layer, with a grid spacing of 5mm-15mm.

6. The insulating shielding cover for high arc environments according to claim 5, characterized in that, The diameter of the shape memory alloy wire is 0.2mm-0.5mm.

7. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The depth of the groove is 3mm-5mm, and the thickness of the shield body outside the groove is at least 1.5mm greater than the depth of the groove.

8. The insulating shielding cover for high arc environments according to claim 1, characterized in that, The outer surface of the shield body is provided with reflective strips and laser markings for indicating voltage level and arc protection level.

9. A method for preparing an insulating shield for a high-arc environment as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Fix the shape memory alloy wire into the mold according to the predetermined coil shape; S2: Preforms for forming an inner lining contact layer, a deformation memory layer, a reinforcing layer and an arc dissipation layer are sequentially laid or injected into the mold, wherein the preforms for the deformation memory layer cover the shape memory alloy wire; S3: Closed mold, one-time vulcanization molding under temperature of 140℃-180℃ and pressure of 5MPa-15MPa; S4: Open the mold, remove the molded shield body, and install the locking mechanism.

10. The preparation method according to claim 9, characterized in that, Before laying the fiber fabric prepreg of the reinforcing layer, a layer of silane coupling agent modified silicone rubber adhesive slurry is uniformly coated on both sides.

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