Sealed Switchgear Door with Internal Sealing Elements

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Solution Overview

Problem

Conventional switch cabinet doors with revolving or lifting mechanisms suffer from incomplete sealing in closed positions, leading to fluid leakage during arc faults, which poses safety risks due to the inability to prevent hot gas and plasma from escaping, and existing labyrinth seals are complex, costly, and have short service lives.

Innovation Solution

The implementation of additional sealing elements on the door leaf and frame that form an extended flow path for fluid flows, reducing velocity and providing a dynamic sealing effect, which protects locking elements from fluid flows and reduces the risk of hot gas and plasma escape, while being simpler and more cost-effective to produce and retrofit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional labyrinth seals are used to prevent fluid flow spread, then sealing effect is improved, but device complexity and production costs increase significantly

Engineering Contradiction:
Improvesealing effectVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The door edge is divided into multiple sealing zones with first and second sealing elements positioned at different locations. Each sealing element addresses specific leakage paths, creating a segmented defense against fluid flow without requiring a complex labyrinth structure throughout the entire door assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Sealing elements are applied locally at critical gap regions between the door leaf and frame rather than using a comprehensive labyrinth seal across the entire door. This localized approach provides effective sealing where fluid flow is most likely to occur while maintaining simplicity in non-critical areas.

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional labyrinth seals are used to prevent fluid flow spread, then sealing effect is improved, but production costs increase due to complex structure

Engineering Contradiction:
Improvesealing effectVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing elements are designed as simple, replaceable components that can be easily manufactured and installed. Rather than investing in expensive, complex labyrinth seal structures, the patent uses affordable sealing elements that provide effective protection and can be replaced if needed, reducing overall production costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If conventional labyrinth seals are used to prevent fluid flow spread, then sealing effect is improved, but service life is reduced due to degradation from hot gas and plasma

Engineering Contradiction:
Improvesealing effectVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The first and second sealing elements are positioned to create a protective barrier before hot gas and plasma can reach the locking elements. This preliminary sealing layer absorbs and deflects the harmful fluid flow, protecting the locking mechanism from thermal and chemical degradation, thereby extending service life.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of operation

If door gap is allowed for revolving/lifting mechanism operation, then door functionality is improved, but sealing performance deteriorates due to gap allowing fluid flow

Engineering Contradiction:
Improvedoor operationVSAvoidsealing performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The sealing elements function as flexible barriers that can accommodate the movement and positioning variations inherent in revolving and lifting door mechanisms. These thin film-like sealing components maintain contact with the door edge throughout the range of motion, providing continuous sealing despite the gap required for mechanical operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2555357B1Electrical cabinet with sealed door
Publication Date: 2017.10.11 SCHNEIDER ELECTRIC SACHSENWERK
  • EP2555357B1 patent drawingFigure 1
  • EP2555357B1 patent drawingFigure 2
  • EP2555357B1 patent drawingFigure 3

AI summary

The invention relates to a control cabinet, in particular for a medium-voltage switchgear, with at least one door (10), wherein the door (10) comprises a door leaf (12) and a frame (14), and wherein the door leaf (12) is locked in a closed position on the frame (14) by means of locking elements. At least two sealing elements (16a, 16b) are provided on the door leaf (12) and on the frame (14). The two sealing elements (16a, 16b) are arranged on the inside of the locking elements.