High Voltage Seal Triple Junction Field Reduction

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Solution Overview

Problem

High voltage structures with ceramic insulators experience high electric fields at triple junctions, leading to electron arcing and punctures, which are not effectively mitigated by existing technologies.

Innovation Solution

The placement of seals on the inside diameter of the insulator reduces electric fields at both inner and outer triple junctions, with a coronal shield extending over the inner triple junction to further minimize electric field magnitude, thereby reducing electron movement and arcing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metallic seal ring is brazed on the outer surface of the ceramic insulator to attach the body, then the attachment strength and sealing are improved, but the electric field at the triple junction becomes high causing arcing and punctures

Engineering Contradiction:
Improveattachment strengthVSAvoidelectric field intensity
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A conductive structure is introduced as an intermediary element between the ceramic insulator and the seal ring. This conductive structure is brazed to the outer surface of the ceramic insulator, creating a controlled interface that manages the electric field distribution at the triple junction, thereby preventing arcing while maintaining the sealing function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductive structure is specifically positioned at the triple junction region where the ceramic insulator, seal ring, and surrounding media meet. This localized placement addresses the high electric field problem at this critical interface without affecting other regions of the insulator, allowing the rest of the structure to maintain its original design and function.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a coronal shield is added to reduce the electric field at the triple junction, then the arcing and puncture risk is reduced, but the device complexity increases

Engineering Contradiction:
Improveelectric field intensityVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The coronal shield function is merged with the existing conductive structure that is already brazed to the ceramic insulator. By integrating the electric field management function into the existing seal assembly, the patent avoids adding separate coronal shield components, thereby reducing device complexity while still achieving the desired reduction in electric field intensity at the triple junction.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration significantly decreases the electric field at the triple junctions, reducing the likelihood of arcing and punctures, while also improving manufacturability and reducing the need for external coronal shields.

Implementation Method 1

An electric field at this triple junction may be relatively high, resulting in electrons that may become the source of arcing and/or punctures

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP3544043B1High voltage seals and structures having reduced electric fields
Publication Date: 2022.02.09 VAREX IMAGING CORP
  • EP3544043B1 patent drawingFigure 1~3
  • EP3544043B1 patent drawingFigure 4~5
  • EP3544043B1 patent drawingFigure 6~7

AI summary

Some embodiments include a structure , comprising: an insulator (102, 402, 502) forming at least a part of a wall of a vacuum chamber, the insulator having a first end (102a, 402a, 502a) and a second end (102b, 402b, 502b) wider than the first end; a first conductive structure (106, 406, 506) disposed at the first end of the insulator; and a second conductive structure (104, 404, or 504) disposed at the second end of the insulator, contacting the insulator, and including at least a portion surrounded by the insulator; wherein: a portion of an outer surface of the insulator extends radially outward from a triple junction (110-1, 410-1, 510-1) between the insulator, the second conductive structure, and a medium (150) contacting the outer surface of the insulator.