Surge Arrestor Module Curing with Variable Bladder Compaction

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Solution Overview

Problem

Existing methods for manufacturing surge arrestors using fiberglass-reinforced epoxy layers face challenges such as inability to vary compaction force and surface defects from shrink film use, leading to inefficiencies and increased operator attention for smoothing.

Innovation Solution

A method involving a flexible bladder to apply compressive force to an epoxy-fiberglass layer around a stack of MOV blocks during curing, allowing for variable pressure and reducing surface defects by using radial and axial pressure sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shrink film is used to compact the fiberglass and epoxy during curing, then compaction force is applied to eliminate air voids, but the compaction level cannot be varied and surface impressions are created requiring post-processing

Engineering Contradiction:

Improveelimination of air voidsVSAvoidvariability of compaction force

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the static shrink film with a dynamic fluid pressure system. A flexible bladder filled with liquid or gas allows the compaction force to be varied by adjusting the fluid pressure, enabling adaptation to different fiberglass layer thicknesses and curing requirements while maintaining consistent contact pressure throughout the curing process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses a fluid pressure system (pneumatic or hydraulic) to apply compaction force through a flexible bladder. This allows for controlled, variable, and uniform pressure application during curing, eliminating the fixed compaction force limitation of shrink film and preventing surface impressions that require post-processing.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Strength

If multiple layers of fiberglass wrapping are applied to increase strength, then the desired wall thickness is achieved, but the amount of compaction force needed to eliminate air voids increases

Engineering Contradiction:

Improvefiberglass wall thicknessVSAvoidcompaction force required

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The fluid pressure system provides scalable compaction force that can be increased proportionally with the number of fiberglass layers. The hydraulic or pneumatic system can generate and control the higher forces needed for thick multi-layer wraps, distributing the force uniformly through the flexible bladder without creating localized surface impressions.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Productivity

If shrink film is removed after curing, then the compaction function is complete, but surface impressions remain requiring sanding and smoothing operations

Engineering Contradiction:

Improvecuring process completionVSAvoidpost-curing surface smoothing

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The fluid pressure system maintains uniform pressure distribution throughout the curing process, preventing the formation of surface impressions that occur with shrink film. This eliminates or minimizes the need for post-curing sanding and smoothing operations, reducing manual labor and increasing production efficiency.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The flexible bladder maintains continuous contact with the curing fiberglass-epoxy composite throughout the process, distributing pressure uniformly and preventing localized impressions. Unlike shrink film that concentrates force at overlap points, the bladder's flexibility allows it to conform perfectly to the curved surface and apply even pressure distribution.

Inventive Principle:

Principle #30Flexible shells and thin films

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 method ensures consistent, void-free surfaces and variable compaction force, enhancing the reliability and efficiency of surge arrestor production without the need for post-curing smoothing.

Implementation Method 1

applying pressure to the flexible bladder to generate a compressive force to the epoxy-fiberglass layer and the stack

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

The epoxy resin, when heated, cures and solidifies to form a very high strength substrate encapsulating the MOV blocks and end contacts

Methodology Applied

Scientific EffectCuring: Phase Change

Data Source

PatentUS11894166B2Manufacturing process for surge arrestor module using compaction bladder system

Publication Date: 2024.02.06 RICHARDS MFG CO INC

AI summary

The present disclosure is directed to a method of producing a surge arrestor module, comprising the acts of (i) providing a plurality of MOV blocks arranged in a stack, (ii) applying an epoxy-reinforced structural layer to an outer surface of the stack, (iii) after the applying, inserting the stack into a flexible bladder, and (iv) curing the epoxy-reinforced structural layer with elevated temperatures while the flexible bladder applies radially aligned pressure to the stack and a tool applies axially aligned pressure to the stack. The present disclosure also includes an apparatus for performing the methods described herein. The apparatus includes an outer case structure and a flexible bladder that fits within the outer case structure. A hollow inner region of the outer case structure is pressurized to force the flexible bladder against the surge arrestor module as the surge arrestor module is curing.