Integrated Varistor and Spark Gap with Thermal Disconnector

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Solution Overview

Problem

Existing overvoltage protection devices combining varistors and gas spark gaps are bulky and cumbersome, with components reaching the end of their life leading to potential explosions or short-circuits, and lack efficient thermal disconnection mechanisms.

Innovation Solution

An integrated component that combines varistor, thermal protection, and spark gap functions into a single discrete unit, utilizing a hot-melt solder thermal disconnector and a heat-shrinkable metal connector to ensure reliable thermal disconnection, with a heat-active material for enhanced temperature management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate varistor, thermal protection, and spark gap components are used, then each component can be optimized independently, but the overall device becomes bulky and cumbersome

Engineering Contradiction:
Improvecomponent optimizationVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the varistor, thermal protection element, and spark gap into a single integrated component where the thermal protection element is positioned between the varistor and spark gap, sharing common electrodes and housing, thereby reducing overall device size while maintaining independent optimization of each protective function

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated component performs multiple protective functions simultaneously: overvoltage protection via the varistor, arc suppression via the spark gap, and thermal disconnection via the thermal protection element, with each element contributing to a unified surge protection system that protects against multiple failure modes

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If traditional thermal disconnecting mechanisms are used, then thermal protection is provided, but temperature distribution becomes non-uniform reducing reliability

Engineering Contradiction:
Improvethermal disconnection reliabilityVSAvoidtemperature distribution
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The thermal protection element is strategically positioned between the varistor and spark gap with specific thermal coupling to the varistor, creating localized thermal management that ensures uniform temperature distribution across the thermal disconnecting mechanism while maintaining independent thermal response characteristics

Inventive Principle:
Principle #3Local quality

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 integrated component provides a compact, reliable, and homogeneous temperature rise for improved thermal disconnection, effectively protecting electrical equipment from overvoltages while preventing component failure and fires.

Implementation Method 1

a hot-melt solder thermal disconnector

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

a heat-shrinkable metal connector

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

the thermoactive material being capable of melting at a temperature rise below the melting temperature of the metal connector

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3316431B1Embedding of a component integrating a thermally protected varistor and a spark gap in series
Publication Date: 2021.04.07 CITEL SA
  • EP3316431B1 patent drawingFigure 1~10

AI summary

The invention relates to an integrated component for transient overvoltage protection, comprising: • a first and a second conductive lead, each of which is suitable for mounting on an electrical circuit; • a gas discharge tube; • a thermally protected varistor comprising: - a varistor body, - a first varistor electrode and a second varistor electrode placed on either side of the varistor body, the varistor body being suitable for heating up when the voltage applied between the first and second varistor electrodes exceeds a voltage threshold; • a thermal disconnector, an electrical connection being made via the thermal disconnector;