Composite Electrical Bushing Insulation for Contamination Resistance
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Solution Overview
Problem
Existing bushings for electrical apparatuses face challenges in providing reliable and cost-effective insulation, particularly in liquid-insulated environments, with issues related to material degradation, contamination, and electrical breakdown.
Innovation Solution
A bushing design utilizing a thermoplastic main part with a silicone elastomer cover, chemically bonded together, offering enhanced hydrophobicity and creepage length, along with a thin wall structure for improved insulation and reduced material consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional insulator materials (ceramics, crosslinked polyethylene) are used, then electrical insulation is provided, but material degradation and contamination occur leading to reduced reliability
Solution Approach 1:
The insulator body combines thermoplastic material (providing structural integrity, chemical resistance, and dimensional stability) with elastomeric material coating (providing hydrophobicity and contamination resistance). This composite structure resolves the contradiction by integrating materials with complementary properties that individually address different aspects of insulation reliability and material stability.
Solution Approach 2:
The patent changes the chemical and physical parameters of the insulator surface by applying an elastomeric coating that provides hydrophobicity. This parameter change (surface energy modification) prevents contamination accumulation and water film formation, thereby maintaining insulation reliability without compromising material stability.
2Reliability
If thick insulator walls are used, then electrical insulation is improved, but material consumption and manufacturing cost increase
Solution Approach 1:
The patent applies a thin elastomeric film coating on the thermoplastic insulator body. This thin film provides hydrophobicity and contamination resistance, allowing the use of thinner overall wall structures while maintaining insulation performance. The flexible elastomeric layer compensates for reduced bulk material thickness by providing surface-level protective functions.
Solution Approach 2:
The composite structure allows optimization of wall thickness by distributing functional requirements between the two materials: thermoplastic provides bulk insulation and structural support with minimized thickness, while elastomeric coating provides surface protection and hydrophobicity, reducing total material consumption compared to traditional single-material thick-walled designs.
3Ease of manufacture
If thermoplastic material is used for the insulator body, then manufacturing cost and complexity are reduced, but adhesion of the elastomeric cover may be insufficient
Solution Approach 1:
The patent modifies the surface parameters of the thermoplastic material (surface energy, roughness, or chemical composition) to enhance adhesion of the elastomeric coating. This parameter change allows simple thermoplastic injection molding while achieving strong interfacial bonding, resolving the contradiction between manufacturing ease and bond strength.
Solution Approach 2:
The thermoplastic material surface acts as an intermediary between the injection molding process and the elastomeric coating application. By controlling surface properties of the thermoplastic, the patent enables direct bonding without complex intermediate layers or procedures, maintaining manufacturing simplicity while ensuring adequate adhesion strength.
4Ease of operation
If the insulator body is exposed to the environment, then access and installation are simplified, but contamination and water accumulation increase electrical breakdown risk
Solution Approach 1:
The elastomeric coating forms a flexible protective shell on the exposed insulator body surface. This thin film barrier prevents contamination and water from directly contacting the thermoplastic surface, maintaining installation accessibility while protecting against harmful environmental factors through the hydrophobic elastomeric layer.
Solution Approach 2:
The patent converts the harmful effect of environmental exposure by using the elastomeric coating's hydrophobicity to actively repel water and contamination. The exposure that would normally be harmful is transformed into a beneficial scenario where the insulator surface actively prevents contaminant accumulation through its hydrophobic properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a reliable, cost-effective, and efficient insulation solution with reduced material usage, minimizing contamination and electrical breakdown risks, while maintaining effective electrical insulation.
Implementation Method 1
The outer cover provides a hydrophobic surface. The outer surface of the outer cover does not easily collect contamination and is efficiently cleaned by rainwater during operation
Implementation Method 2
The outer cover is fixed to the main part. The outer cover adheres firmly to the main part. The chemical bond connects the cover and the main part together
Data Source
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AI summary
A bushing (100) for a liquid-insulated electrical apparatus (200) is disclosed. The bushing (100) comprises an electrical conductor (101) and an insulator body (110) through which the electrical conductor (101) extends, wherein the insulator body (110) comprises a main part (112) and an outer cover (150), the outer cover (150) covering the main part (112) at least in part, the main part (122) is made of thermoplastic (115) and the external cover (150) is made of elastomeric material (151), wherein the main part (112) and the outer cover (150) are fixed to each other by a chemical bond.