Terminal Bushing Sealing Element for Sound Attenuation

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Solution Overview

Problem

Existing terminal bushing seals for power capacitors fail to effectively reduce noise while maintaining the necessary creepage distance, leading to moisture and water ingress into sound attenuation enclosures.

Innovation Solution

An elastic terminal bushing sealing element with an annular shape and inclined wall portion, featuring a radially inwardly extending circumferential protrusion and spherical sealing protrusion, is designed to fit between the terminal bushing and barrier element, ensuring effective sealing against moisture and water while maintaining the creepage distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a sealing element is arranged in the opening of the sound attenuation enclosure and in abutment with sheds of the terminal bushing, then noise isolation and moisture protection are improved, but the creepage distance of the terminal bushing is reduced

Engineering Contradiction:
Improvenoise isolation and moisture protectionVSAvoidcreepage distance
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The sealing element is divided into functionally distinct parts: a first sealing portion that contacts the terminal bushing base to provide environmental sealing, and a second sealing portion that contacts the sheds to provide noise isolation. This segmentation allows each portion to perform its specific function without compromising the overall creepage distance requirement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the sealing element have different properties and functions. The first sealing portion is designed for environmental sealing with specific dimensional characteristics, while the second sealing portion is designed for noise isolation with different dimensional characteristics. This local differentiation optimizes performance while maintaining creepage distance.

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If longer cable bushings are used to compensate for creepage distance loss, then creepage distance is maintained, but cost increases

Engineering Contradiction:
Improvecreepage distanceVSAvoidcost
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

By segmenting the sealing function into two distinct portions, the patent eliminates the need for longer cable bushings. The first sealing portion protects the terminal bushing base while the second sealing portion handles noise isolation, allowing the use of standard-length bushings and reducing overall system cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element acts as an intermediary component that provides both environmental sealing and noise isolation functions. This mediator eliminates the need to extend the terminal bushing length, thereby avoiding the increased cost associated with longer cable bushings.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the sealing element provides comprehensive sealing against moisture and water, then protection against environmental impacts is improved, but the design complexity increases

Engineering Contradiction:
Improveprotection against environmental impactsVSAvoidsealing element design
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges two sealing functions into a single integrated sealing element. The first sealing portion provides environmental sealing at the terminal bushing base, while the second sealing portion provides noise isolation at the sheds. This consolidation simplifies the overall design compared to using separate components for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing element is designed as a multi-functional component that simultaneously provides environmental sealing and noise isolation. This universal design approach reduces the number of separate components needed, thereby reducing design complexity while maintaining comprehensive protection.

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

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 provides improved sound attenuation and protection against environmental factors while preserving the creepage distance, allowing for longer service life and compatibility with various sound attenuation arrangements.

Implementation Method 1

any water that might exist inside the sealing element, between the sealing element and the terminal bushing, will flow outwards from the barrier element instead of inwards

Methodology Applied
Scientific EffectGravity-driven flow: Gravitation

Implementation Method 2

sealing element which is elastic, has an annular shape

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3008736B1Terminal bushing sealing element
Publication Date: 2017.08.09 ABB (SCHWEIZ) AG
  • EP3008736B1 patent drawingFigure 1~7
  • EP3008736B1 patent drawingFigure 2~3
  • EP3008736B1 patent drawingFigure 4

AI summary

The present invention relates to a terminal bushing sealing element (201, 401, 501', 501'', 601, 701), adapted to be fitted between a terminal bushing (402, 502, 602, 702) and a barrier element (403, 503, 603, 703), The sealing element (201, 401, 501', 501'', 601, 701) is elastic, has an annular shape, and comprises a wall (204, 404, 504, 704) with an inner surface and an outer surface. A first opening (206, 406, 506) is provided at a first end (207, 407, 507) of the sealing element and a second opening (208, 408, 508) is provided at a second end (209, 409, 509) of the sealing element, which is opposite to the first end and the wall (204, 404, 504, 704) extends between the first end (207, 407, 507) and the second end (209, 409, 509). The wall (204, 404, 504, 704) comprises a first wall portion (205, 405, 505) that is inclined such that a diameter of the sealing element (201, 401, 501', 501'', 601, 701) increases from the first end (207, 407, 507) in the direction towards the second end (209, 409, 509). The sealing element provides for improved sound attenuation while maintaining a long creepage distance and may be used in sound attenuation casings that are included in power capacitor arrangements.