High-Shear Mixing for Electrical Insulator Production

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Solution Overview

Problem

The existing manufacturing process for high or medium voltage electrical insulators is time-consuming due to the lengthy mixing of highly filled insulation materials, typically taking over 1 hour, and results in incomplete dispersion of fillers, leading to potential degradation under high electric fields.

Innovation Solution

A method utilizing a fast rotating conveying screw to mix all liquid components of the insulating material with fillers through a static mixer, followed by curing in a mould, optimizing filler distribution according to a Fuller sieve curve, significantly reducing mixing time and enhancing filler dispersion and content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional impeller mixing systems are used for highly filled insulation material, then complete filler dispersion is achieved, but mixing time exceeds 1 hour

Engineering Contradiction:

Improvefiller dispersion qualityVSAvoidmixing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the conventional impeller mixing system with a high-shear mixer that uses a rotor-stator mechanism. This mechanical substitution creates intense shear forces that rapidly disperse fillers throughout the resin and hardener mixture, achieving complete filler dispersion in approximately 1 minute compared to over 1 hour with traditional impeller mixers, thus resolving the contradiction between mixing time and dispersion quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If higher filler content is used in insulation material, then mechanical properties and thermal conductivity improve, but mixing time increases significantly

Engineering Contradiction:

Improvemechanical propertiesVSAvoidmixing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The high-shear rotor-stator mixing system generates intense shear forces that efficiently distribute high volumes of filler particles throughout the resin matrix. This mechanical approach enables the production of highly filled insulation materials (with improved mechanical properties and thermal conductivity) while maintaining a mixing time of approximately 1 minute, whereas conventional systems would require excessively long mixing times for such high filler loads.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional mixing systems are used, then equipment complexity is low, but productivity is reduced due to lengthy mixing process

Engineering Contradiction:

Improvemixing system complexityVSAvoidproduction throughput

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent employs a high-shear rotor-stator mixing system that, while more complex than conventional impeller mixers, dramatically reduces mixing time from over 1 hour to approximately 1 minute. This substitution increases production throughput by a factor of more than 30, far compensating for the additional equipment complexity through the rapid production cycle enabled by the high-shear mixing mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach reduces mixing time by a factor of 10, increases throughput, allows for higher filler content, minimizes material losses, and improves mechanical properties and thermal conductivity, resulting in more reliable and cost-effective electrical insulators.

Implementation Method 1

forcing the components with the at least one filler through a tube comprising a fast-turning screw mixing device mixing the components with the at least one filler to a final mixture

Methodology Applied

Scientific EffectShear mixing: Shear Stress

Implementation Method 2

forcing all liquid components of an insulating material of the electrical insulator through a static mixer

Methodology Applied

Scientific EffectStatic mixing:

Implementation Method 3

forming an electrical insulator by at least partially curing the final mixture

Methodology Applied

Scientific EffectCuring:

Implementation Method 4

automatic pressure gelation; a process which can also be vacuum assisted

Methodology Applied

Scientific EffectGelation:

Implementation Method 5

the mould being located in a vacuum chamber the inlet of the vacuum chamber connected to an outlet of the mixing device

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentEP2372725B1Production of electrical insulation and insulated products

Publication Date: 2013.09.11 ABB RES LTD

Figure 1~2
Figure 3~4
Figure 5~6B

AI summary

This invention relates to a method (100) for manufacturing an electrical insulator for medium or high voltage equipment. The method (100) comprises the steps of forcing all liquid components of an insulating material of the electric insulator through a static mixture (101); adding at least one filler to the components (102); forcing the components with the at least one filler through a tube comprising a fast-turning screw mixing device mixing the components with the at least one filler to a final mixture of the insulating material (103); leading the final mixture to a mould, for example of a hot press, or a mould for vacuum casting, the mould being located in a vacuum chamber the inlet of the vacuum chamber connected to an outlet of the mixing device that is fluidly connected to the mould (104a, 104b); forming an electrical insulator by at least partly curing the final mixture (105); and moulding the electrical insulator (106). The curing may be part of the moulding.