Getter Welding on Copper Vacuum Interrupters

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Solution Overview

Problem

Existing methods for attaching getters to structural components in vacuum interrupters, particularly those made of copper, face challenges due to copper's high thermal conductivity, which prevents effective welding by dissipating energy quickly, making mechanical deformation necessary and limiting direct welded connections.

Innovation Solution

Applying an intermediate layer of electrically and thermally poorly conductive metal, such as CrNi, to the structural component surface allows for successful welding of getters by methods like spot welding, laser welding, or ultrasonic welding, even on copper components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If copper structural components are used in vacuum interrupters, then electrical conductivity is improved, but welding capability deteriorates due to high thermal conductivity dissipating energy quickly

Engineering Contradiction:
Improveelectrical conductivityVSAvoidwelding capability
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

An intermediate layer made of electrically and thermally poorly conductive metal is applied to the copper structural component surface. This intermediate layer serves as a mediator that enables welding by retaining thermal energy during the welding process, while the copper substrate maintains its high electrical conductivity. The intermediate layer prevents excessive heat dissipation into the copper, allowing the welding zone to reach sufficient temperatures for proper welding.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If mechanical deformation is used to attach getters to copper components, then welding capability is improved, but manufacturing time increases

Engineering Contradiction:
Improveattachment capabilityVSAvoidmanufacturing time
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The intermediate layer enables direct welded connections between the getter carrier and copper structural components, replacing the need for mechanical deformation methods. This intermediary layer allows for faster, more efficient welding processes compared to time-consuming mechanical attachment methods, thereby improving productivity while maintaining attachment capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If an intermediate layer is applied to enable welding, then welding capability is improved, but device complexity increases

Engineering Contradiction:
Improvewelding capabilityVSAvoidstructure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The intermediate layer changes the thermal and electrical conductivity parameters of the structural component surface. By modifying these physical parameters locally at the attachment area, the copper component gains welding capability without fundamentally changing its overall structure or composition. This parameter change approach adds minimal complexity while enabling the desired welding function.

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

Enables reliable attachment of getters to copper-based structural components without mechanical deformation, expanding the possibilities for welded connections beyond stainless steel materials and improving the vacuum integrity within vacuum interrupters.

Implementation Method 1

the surface of the structural component of a vacuum interrupter intended for fastening the getter is provided as a base for the getter with an intermediate layer made of an electrically and thermally poorly conductive metal

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

an intermediate layer made of an electrically and thermally poorly conductive metal

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

This getter is used to absorb gases that are produced during operation of the vacuum interrupter and can degrade the quality of the vacuum

Methodology Applied
Scientific EffectGas absorption: Absorption (physical)

Data Source

PatentEP2140468B1Method for securing a getter for a vacuum switching tube and vacuum switching tube
Publication Date: 2015.08.26 SIEMENS AG
  • EP2140468B1 patent drawingFigure 1~2

AI summary

The invention relates to a vacuum switching tube in which construction components (13) consisting of copper can be welded to a getter (33) if the copper material (13) is provided at least in the region of the getter having an intermediate layer (35) that is made of a metal that is a poor electric and thermal conductor.