Staged Burner Combustion Chamber with Tangential Air Injection

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Solution Overview

Problem

Existing solid fuel fireplaces with staged burners face challenges in optimizing combustion while maintaining aesthetic qualities of the flame, as previous designs often compromise flame aesthetics for efficient combustion, leading to unsightly small flames and increased polluting gas emissions.

Innovation Solution

A staged burner design with a first hollow body of conical shape and a secondary air supply duct that injects air tangentially, featuring a sinusoidal or sawtooth cutout at the upper end to enhance mixing of pyrolysis gases with secondary air, combined with oblique guide fins to induce circular movement, ensuring complete combustion and a wide, calm flame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If secondary air is introduced through numerous holes in a truncated cone configuration, then combustion efficiency is improved, but flame aesthetics deteriorate due to small unsightly flames

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidflame aesthetics
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The secondary air supply is segmented into multiple injection zones along the conical body, with air introduced through carefully positioned openings rather than numerous holes. This segmentation allows controlled air distribution that maintains combustion efficiency while avoiding the creation of multiple small flames that would degrade aesthetics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the conical body have different air injection characteristics. The secondary air is introduced at specific locations and angles to create localized mixing zones that promote complete combustion without generating unsightly small flames throughout the combustion chamber.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If air distribution is staged to optimize combustion and limit polluting emissions, then environmental performance is improved, but device complexity increases

Engineering Contradiction:
Improvepolluting gas emissionsVSAvoidair distribution system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The primary and secondary air supply systems are merged into an integrated staged combustion design. The conical body serves dual functions as both a structural element and a secondary air distribution mechanism, reducing the need for separate complex air distribution components while maintaining effective pollution control.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conical body structure itself serves as the secondary air distribution mechanism, with air injection features integrated directly into the conical geometry. This self-service approach eliminates the need for additional complex air distribution devices while achieving the required staged combustion for pollution reduction.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the upper end of the first hollow body is smooth without cutouts, then manufacturing is simplified, but mixing of pyrolysis gases with secondary air is insufficient leading to incomplete combustion

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcombustion completeness
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The upper end of the conical body incorporates curved cutouts with sinusoidal or sawtooth patterns rather than straight geometric shapes. These curved configurations enhance gas mixing through improved flow dynamics while remaining manufacturable using standard forming and cutting processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cutout geometry parameters (shape, size, distribution) are optimized to balance manufacturing complexity with mixing performance. The sinusoidal and sawtooth patterns provide sufficient turbulence for complete combustion while being achievable through conventional manufacturing methods, representing an optimal parameter selection.

Inventive Principle:
Principle #35Parameter changes

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 achieves optimized combustion efficiency with reduced polluting gas emissions and enhances flame aesthetics by producing a large, calm, and dancing orange-yellow flame, addressing the need for both efficient combustion and aesthetic appeal.

Implementation Method 1

the upper end of the first hollow body where the secondary air supply duct opens has a cutout in the form of a succession of projections and recesses

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

oblique guide fins to induce circular movement

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Implementation Method 3

secondary combustion of the gases from primary combustion

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

A first phase takes place at the level of the fuel bed which, brought to high temperature, decomposes into combustible gas

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentEP3108180B1Solid-fuel combustion chamber
Publication Date: 2019.10.16 STUV
  • EP3108180B1 patent drawingFigure 1~2
  • EP3108180B1 patent drawingFigure 3~4
  • EP3108180B1 patent drawingFigure 5~6

AI summary

The present invention relates to a solid-fuel combustion chamber comprising a staged burner with a lower stage in which, during use, primary combustion of the solid fuel takes place and with an upper stage in which, during use, secondary combustion of the gases (12) derived from the primary combustion takes place, said burner comprising in the upper stage: a first hollow body (4) intended to accommodate, within its interior volume, the gases (12) derived from the primary combustion, said first hollow body (4) comprising a conical part, and a secondary-air duct (8) arranged around said first hollow body (4) and opening at the upper end thereof, said duct (8) being delimited, on the one hand, by the first hollow body (4) and, on the other hand, by a wall of a shape that substantially complements that of the first hollow body (4) so as to ensure parallel injection of the secondary air along the first hollow body (4).