Metal Foam Cooling Filter for High-Voltage Arc Gas Management

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Solution Overview

Problem

Existing cooling devices for hot gases generated by internal arc faults in metal-enclosed high-voltage switchgear have limitations, including low reproducibility, dust generation, and limited cooling capacity, which pose risks to operators and do not adequately control gas expansion or pressure increases.

Innovation Solution

A metal foam cooling filter with a honeycomb structure, comprising cells that provide openings in all directions, is used to slow down and cool hot gases, promoting turbulence and maintaining pressure within safe limits, made from materials like aluminum or cast iron.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If pozzolan-based coolers are used, then cooling capacity is provided, but dust is generated which impacts dielectric aging and reproducibility is poor

Engineering Contradiction:
Improvegas temperatureVSAvoiddust generation
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent uses metal foam with controlled porosity (open-cell structure) as the cooling filter material. This porous metal structure provides cooling capacity through its thermal mass and surface area while avoiding dust generation, as the metal foam maintains structural integrity and does not disintegrate like pozzolan materials.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention employs metal foam, which can be considered a composite material structure combining metallic properties (strength, non-dusting) with porous characteristics (cooling capacity, gas permeability). This composite approach resolves the contradiction between providing cooling and avoiding harmful dust generation.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If simple perforated sheets or stacked metal mesh are used, then device complexity is reduced, but cooling capacity is limited

Engineering Contradiction:
Improvefilter structure complexityVSAvoidgas cooling capacity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

Metal foam provides superior cooling capacity compared to simple perforated sheets or stacked mesh while maintaining relatively simple installation. The porous structure offers large surface area and thermal mass for cooling, yet the component itself is a single integrated element, balancing complexity and performance.

Inventive Principle:
Principle #31Porous materials

3Stress or pressure

If hot gases are evacuated at high velocity, then pressure build-up in the cavity is prevented, but gas flow bounces against walls creating danger for operators

Engineering Contradiction:
Improvepressure build-up preventionVSAvoidoperator safety risk from hot gas flow
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The metal foam cooling filter acts as an intermediary element between the high-pressure arc chamber and the evacuation path. It reduces gas velocity through its porous structure and thermal mass, allowing pressure relief while preventing dangerous high-velocity hot gas flow from reaching operator areas.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal foam changes the parameters of the gas flow by reducing velocity and temperature while maintaining pressure relief. The porous structure creates flow resistance that slows the gas, and the thermal mass absorbs heat, transforming the hazardous high-velocity hot flow into a safer lower-velocity cooler flow.

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 solution effectively slows gas velocity, cools gases, contains combustion, and manages pressure peaks without increasing pressure, enhancing safety and compliance with industry standards like IEC 62271-200 and IEC 62271-202.

Implementation Method 1

The metal foam filter 32 is designed to slow down the speed of the hot gases 19 and to create turbulence inside the cell 12

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

The metal foam filter 32 is designed to slow down the speed of the hot gases 19 and to create turbulence inside the cell 12. The filter 32 must also be capable of cooling the temperature of these gases

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

The device according to the invention makes it possible to contain the combustion of flammable gases inside the metal casing 10 or the downstream volume

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 4

The filter 32 must also be capable of cooling the temperature of these gases and of creating turbulence while not increasing the pressure peaks in the cell 12 or in the downstream volume

Methodology Applied
Scientific EffectPressure absorption: Absorption (physical)

Data Source

PatentEP3182538B1Device for cooling hot gases in a high-voltage apparatus
Publication Date: 2021.02.03 SCHNEIDER ELECTRIC IND SAS
  • EP3182538B1 patent drawingFigure 1~2
  • EP3182538B1 patent drawingFigure 3~4
  • EP3182538B1 patent drawingFigure 5

AI summary

The invention relates to a device for cooling hot gases generated by an internal arc in high-voltage switchgear with a metal enclosure or a prefabricated high-voltage/low-voltage substation. This device comprises a cooling filter made of metallic foam having a honeycomb structure.