Elastic Upper Shell Flameproof Gap Design

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Solution Overview

Problem

Existing explosion-proof pressure-tight housings for electrical operating devices in the industrial field are complex, expensive, and require large volumes and thick walls, making them unsuitable for efficient protection of potential ignition sources like electronic modules.

Innovation Solution

A compact explosion-proof housing design featuring a rigid lower shell with inclined outer surfaces and an elastic upper shell that forms a flameproof gap, allowing for a press-fit connection without the need for casting resin, optimizing volume usage and reducing material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional explosion-proof housing designs are used with thick walls and complex structures, then explosion protection reliability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveexplosion protection reliabilityVSAvoidhousing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The housing is divided into two distinct segments: a rigid lower shell providing structural stability and an elastic upper shell providing explosion protection through deformation. This segmentation allows each part to be optimized for its specific function, reducing overall complexity while maintaining reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the mechanical parameter of the upper shell from rigid to elastic, allowing it to deform under explosion pressure. This parameter change enables thinner walls while maintaining protection reliability, as the elastic material absorbs explosion energy through deformation rather than requiring thick rigid walls.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional explosion-proof housings with large volumes and thick walls are used, then explosion protection is improved, but weight and material usage increase

Engineering Contradiction:

Improveexplosion protectionVSAvoidhousing weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The upper shell is designed with elastic properties instead of rigid construction, fundamentally changing the mechanical parameter. This allows the shell to be thinner and lighter while still providing adequate explosion protection through controlled deformation that prevents flame transmission.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastic upper shell functions as a flexible protective barrier that can deform under explosion pressure. This flexible shell approach replaces traditional thick rigid walls, significantly reducing weight and material usage while maintaining the flameproof enclosure function.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If rigid housing structures with flameproof gaps are used, then explosion protection is maintained, but the housing cannot accommodate dimensional tolerances and assembly variations

Engineering Contradiction:

Improveflameproof gap integrityVSAvoidassembly tolerance accommodation

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The upper shell transitions from a static rigid structure to a dynamic elastic structure that can adapt its shape. This dynamic property allows the shell to accommodate assembly tolerances and dimensional variations while maintaining the critical flameproof gap integrity under normal and explosion conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The elastic upper shell acts as a flexible component that can deform to accommodate manufacturing tolerances and assembly variations. This flexibility ensures that the flameproof gap dimensions remain within required limits despite variations in rigid lower shell dimensions or assembly precision.

Inventive Principle:

Principle #30Flexible shells and thin films

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 design provides effective explosion protection with smaller wall thicknesses and reduced weight, simplifying configuration while ensuring the housing remains secure and resistant to abnormal gaps during explosions.

Implementation Method 1

the cover has an elastic zone in the transition region between the cylindrical fitting portion and the cover base

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the side walls of the elastic upper shell and the side walls of the rigid lower shell, such that a flameproof gap is formed

Methodology Applied

Scientific EffectGeometric containment: Geometry

Data Source

PatentUS11706880B2Explosion-proof pressure-tight housing for electrical operating devices

Publication Date: 2023.07.18 SIEMENS AG

AI summary

An explosion-proof pressure-tight housing for electrical operating device has a rigid lower shell and an elastic upper shell terminating the lower shell in the manner of a cover, wherein the lower shell includes a base, preferably formed as a rounded rectangle, and also includes side walls, the outer surfaces of which are inclined inwardly by an acute angle, where the elastic upper shell has a cover base and side walls, which are splayed outwardly at the angle, the inside width of the upper shell is smaller than the outside width of the lower shell, and the upper shell is pressed with the lower shell such that a flameproof gap is formed between the side walls of the upper shell and the side walls of the lower shell.