Hot Blast Stove Dome Segmentation for Thermal Expansion

Solution Overview

Problem

Conventional hot blast stoves suffer from premature dome failure due to differential thermal expansion between the combustion and checker chamber walls, leading to cracks and increased maintenance costs, as additional insulation and refractory walls provide limited protection against expansion variations.

Innovation Solution

A hot blast stove dome design featuring a vertical expansion joint between dome portions supported by the combustion and checker chamber walls allows independent expansion, eliminating adverse thermal effects and enabling the omission of additional insulation and refractory layers, thereby reducing cracking and construction costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional insulation and dense refractory walls are added to reduce thermal expansion, then dome cracking is reduced, but device complexity and construction costs increase

Engineering Contradiction:

Improvedome cracking resistanceVSAvoidwall structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dome is divided into two separate support zones: an inner dome portion supported by the combustion chamber wall and an outer dome portion supported by the checker chamber wall. This segmentation allows each portion to independently accommodate thermal expansion of its supporting wall, eliminating the need for additional insulation and refractory layers while preventing dome cracking.

Inventive Principle:

Principle #1Segmentation

2Reliability

If additional insulation and refractory layers are added, then thermal expansion differences are compensated, but manufacturing costs and construction time increase

Engineering Contradiction:

Improvedome structure stabilityVSAvoidconstruction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The dome is divided into two separate support zones: an inner dome portion supported by the combustion chamber wall and an outer dome portion supported by the checker chamber wall. This segmentation allows each portion to independently accommodate thermal expansion of its supporting wall, eliminating the need for additional insulation and refractory layers while preventing dome cracking.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the dome is supported by a single wall structure, then construction is simpler, but differential thermal expansion causes premature dome failure

Engineering Contradiction:

Improvesupport structure simplicityVSAvoiddome lifespan

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The dome is divided into two separate support zones: an inner dome portion supported by the combustion chamber wall and an outer dome portion supported by the checker chamber wall. This segmentation allows each portion to independently accommodate thermal expansion of its supporting wall, eliminating the need for additional insulation and refractory layers while preventing dome cracking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The expansion joint acts as an intermediary element between the inner and outer dome portions, allowing independent movement and accommodating differential thermal expansion between the combustion chamber wall and checker chamber wall, thereby preventing stress transmission that would cause cracking.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If repairs are conducted on cracked domes, then dome integrity is restored, but production downtime and maintenance costs increase

Engineering Contradiction:

Improvedome integrityVSAvoidproduction downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The expansion joint is installed during initial construction to preemptively accommodate thermal expansion differences, preventing dome cracking before it occurs and eliminating the need for future repairs and production downtime.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The expansion joint provides beforehand cushioning by accommodating differential thermal expansion before it can cause stress concentrations and cracking in the dome structure, thereby preventing premature dome failure and avoiding maintenance interruptions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 significantly reduces dome cracking and maintenance costs, extends the lifespan of the dome and refractory system, and increases heat storage capacity and combustion chamber area, minimizing downtime and vibration.

Implementation Method 1

the wall on the combustion chamber side of the blast stove expands faster and thermally cycles more, causing significant expansion and contraction during normal operating cycles

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2534269B1Hot blast stove dome and hot blast stove

Publication Date: 2016.04.20 ALLIED MINERAL PRODUCTS INC

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AI summary

A hot blast stove dome comprises a first dome portion adapted for support on a combustion chamber wall of a hot blast stove, and a second dome portion adapted for support on a checker chamber wall of a hot blast stove, wherein a vertical expansion joint is provided between the first dome portion and the second dome portion and is adapted to allow the first dome portion and the second dome portion to independently accommodate vertical expansion of their respective supporting walls. The dome is suitably provided in a hot blast stove which comprises a combustion chamber, a checker chamber, a cylindrical housing comprising a combustion chamber wall and a checker chamber wall.