Air-Cooled Through-Wall Bushing Using Pressure-Driven Ventilation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing air-cooled wall bushings struggle to maintain adequate cooling when close to current limits, particularly in high-voltage applications, due to reliance on natural convection which may not provide sufficient cooling.

Innovation Solution

A ventilation channel with openings at both ends of the bushing allows cooling air to flow through, driven by a pressure difference across the wall, eliminating the need for forced air circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If natural convection cooling is used, then the bushing structure is simple, but the cooling efficiency is insufficient when close to current limits

Engineering Contradiction:
Improvebushing structureVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The bushing utilizes the natural pressure difference across the wall to drive cooling air flow through the ventilation channel, eliminating the need for external fans or compressors. The system serves itself by leveraging the existing pressure gradient between indoor and outdoor environments to achieve forced convection cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention employs pneumatic principles by using air flow through the ventilation channel to remove heat from the conductor. The pressure difference-driven air flow creates forced convection, significantly improving heat dissipation compared to natural convection alone.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If forced air circulation is used to improve cooling, then cooling efficiency increases, but device complexity increases due to need for fans or compressors

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The bushing utilizes the natural pressure difference across the wall to drive cooling air flow through the ventilation channel, eliminating the need for external fans or compressors. The system serves itself by leveraging the existing pressure gradient between indoor and outdoor environments to achieve forced convection cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The ventilation channel acts as an intermediary structure that facilitates heat transfer from the conductor to the surrounding air. It provides a dedicated pathway for cooling air to flow through, enhancing heat dissipation without requiring active cooling devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If ventilation channel with both-end openings is used, then cooling air flow is enhanced by pressure difference, but bushing structure becomes more complex

Engineering Contradiction:
Improvecooling air flowVSAvoidbushing structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The bushing utilizes the natural pressure difference across the wall to drive cooling air flow through the ventilation channel, eliminating the need for external fans or compressors. The system serves itself by leveraging the existing pressure gradient between indoor and outdoor environments to achieve forced convection cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The ventilation channel serves multiple functions: it provides structural support for the insulating material, creates a dedicated pathway for cooling air flow, and facilitates heat dissipation from the conductor. This multi-functionality reduces the need for additional separate cooling components.

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

Effectively cools the bushing by utilizing natural pressure differences to facilitate air flow, enhancing cooling efficiency without the need for fans or compressors.

Implementation Method 1

cooling air may flow through the channel to cool the bushing driven by a pressure difference across the bushing

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

cooling air is circulated upon heating thereof

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3852123B1Air-cooled air-to-air bushing
Publication Date: 2026.03.11 HITACHI ENERGY LTD
  • EP3852123B1 patent drawingFigure 1~3

AI summary

The present disclosure relates to an air-to-air through-wall bushing (1) comprising a conductor (11), insulation (13) surrounding the conductor, a ventilation inlet at a first end (15a) of the bushing, and a ventilation outlet at a second end (15b) of the bushing. The inlet and outlet allow cooling air to pass through a ventilation channel (14) within the bushing.