Thermoplastic Insulating Plug for Recyclable Medium-Voltage Sealing

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Solution Overview

Problem

Existing insulating plugs for high-voltage systems are difficult to recycle, have complex molding processes, and do not meet the requirements for medium voltage separable connectors, such as IP 56 rating, electrical stability up to 20.8/36 (42) kV, and a 40-year service life.

Innovation Solution

A thermoplastic insulating plug with a fully recyclable design, made from thermoplastic materials such as polyoxymethylene (POM), polyamide (PA), or polyphenylene sulfide (PPS), which reduces raw material and energy usage by 25% compared to traditional solutions, and features a simpler molding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional insulating plugs with brass or aluminum inserts and epoxy resin bodies are used, then electrical stability and sealing performance are achieved, but manufacturing complexity increases and recyclability decreases

Engineering Contradiction:
Improveelectrical stabilityVSAvoidmolding process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameters from traditional brass/aluminum inserts with epoxy resin to fully thermoplastic materials (POM, PA, or PPS). This parameter change simplifies the molding process while maintaining electrical stability through proper material selection and composition, resolving the contradiction between reliability and manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite thermoplastic materials, specifically combining base thermoplastic polymers (POM, PA, or PPS) with carbon black to create semiconductive parts. This composite approach maintains the electrical stability required for high-voltage applications while enabling simpler single-material molding processes that improve manufacturability

Inventive Principle:
Principle #40Composite materials

2Reliability

If traditional insulating plugs with epoxy resin and metal inserts are used, then electrical stability is maintained, but recyclability and environmental impact worsen

Engineering Contradiction:
Improveelectrical stabilityVSAvoidcarbon footprint
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material composition parameters to use fully thermoplastic materials instead of thermosetting epoxy resin and metal inserts. Thermoplastic materials can be melted and remolded, enabling recyclability and reducing carbon footprint while maintaining electrical stability through appropriate material selection and carbon black addition for semiconductive properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent enables discarding and recovering of insulating plugs by using fully thermoplastic materials that can be ground into granulates and remolded into new products. This recovering process reduces waste and carbon footprint while the maintained electrical stability ensures continued suitability for high-voltage applications

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If traditional insulating plugs are used, then sealing performance is achieved, but production cost and energy consumption increase

Engineering Contradiction:
Improvesealing performanceVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple components (insulation body, semiconductive parts, and sealing elements) into a single integrated thermoplastic molded part. This consolidation eliminates the need for separate metal inserts and complex assembly steps, reducing production time and energy consumption while maintaining sealing performance through integrated design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the material parameter from epoxy resin to thermoplastic materials, which have shorter processing cycles and lower energy requirements for molding. This parameter change improves productivity and reduces production costs while the material properties are selected to maintain adequate sealing performance for IP 56 rating

Inventive Principle:
Principle #35Parameter changes

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 thermoplastic insulating plug achieves a 30% cost reduction and improved carbon footprint due to reduced production waste and the use of recyclable materials, while meeting the demanding requirements for medium voltage applications, including IP 56 rating and 40-year service life.

Implementation Method 1

injection molding both first and second semiconductive parts respectively with the mixture composition

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 2

injection molding both first and second semiconductive parts respectively with the mixture composition, overmolding the insulation body over the first and second semiconductive parts

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP4509288A1Thermoplastic insulating plug and fabrication process thereof
Publication Date: 2025.02.19 NEXANS SA
  • EP4509288A1 patent drawingFigure 1~2
  • EP4509288A1 patent drawingFigure 3~5
  • EP4509288A1 patent drawing

AI summary

An insulating plug is suitable to bolt a connector system comprising a connector, wherein the insulating plug comprises - an insulation body to seal an insulation bushing of the connector, - a first semiconductive part provided with a threaded screw base to engage an end of a connecting bolt of the connector, and - a second semiconductive part opposite to the first semiconductive part, the insulation body comprising a transverse plate between both first and second semiconductive parts, such that both first and second semiconductive parts comprise a base plate and a flange, the transverse plate being adjacent to both base plates, wherein the insulation body, first semiconductive part and second semiconductive part are all made of thermoplastic materials.