Combi Stove Airflow Layout for Cleaner Granular Fuel Combustion

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Solution Overview

Problem

Conventional combi stoves that burn both wood logs and granular materials face challenges in maintenance and cleaning due to the buildup of ash and slag, and they often produce polluted emissions due to inefficient airflow.

Innovation Solution

A combi stove design with a common combustion chamber featuring a granular material combustion area surrounded by a releasable sidewall with airflow apertures, a grate-separated log combustion area, and ash collecting means, which allows for controlled airflow and easy cleaning by enabling airflow through both bottom and sidewall apertures, and includes a granular material feeding system and flue means for efficient combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a large and fast airflow is used to ensure complete combustion of granular material, then combustion efficiency is improved, but ash and slag are drawn out with flue gas causing polluted emissions

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidpolluted emissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The airflow system is segmented into multiple independent airflow paths: bottom airflow apertures for primary combustion air, sidewall airflow apertures for secondary combustion air, and separate flue gas extraction. This segmentation allows controlled airflow distribution that maintains complete combustion while preventing excessive airflow from drawing ash particles into emissions.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the granular material combustion area is designed with fixed sidewalls for structural integrity, then manufacturing simplicity is improved, but cleaning and maintenance become difficult due to ash and slag buildup

Engineering Contradiction:
Improvestructural integrityVSAvoidcleaning accessibility
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The sidewall transitions from a fixed structure to a movable one. The rear sidewall portion is designed to be movable between a first position (for normal operation) and a second position (for cleaning access). This dynamic design allows the structure to adapt between maintaining structural integrity during combustion and providing cleaning accessibility when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sidewall is segmented into a fixed front portion and a movable rear portion. This segmentation allows the front portion to maintain structural integrity while the rear portion can move to provide cleaning access, resolving the contradiction between structural strength and maintenance accessibility.

Inventive Principle:
Principle #1Segmentation

3Productivity

If bottom airflow apertures are increased for efficient granular material combustion, then combustion completeness is improved, but ash particles are drawn out with flue gas increasing pollution

Engineering Contradiction:
Improvecombustion completenessVSAvoidash particle emission
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Different regions of the combustion chamber are given different airflow characteristics. The bottom airflow apertures provide controlled primary air for combustion, while sidewall airflow apertures provide secondary air. This local differentiation allows efficient combustion in the granular material area while preventing excessive airflow from drawing ash particles into the flue gas stream.

Inventive Principle:
Principle #3Local quality

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 ensures complete combustion with reduced ash and slag buildup, easy maintenance, and cleaner emissions by allowing controlled airflow and easy access for cleaning, while maintaining the functionality of burning both logs and granular materials efficiently.

Implementation Method 1

bottom airflow apertures arranged to enable an airflow to the granular material during a combustion of the granular material

Methodology Applied
Scientific EffectAirflow: Convection

Implementation Method 2

sidewall airflow apertures arranged to enable an airflow to flue gasses generated during a combustion of the granular material

Methodology Applied
Scientific EffectAirflow: Convection

Implementation Method 3

both the logs and the granular material may be combusted in the common combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3559553B1A combi stove and use of a combi stove
Publication Date: 2020.07.15 ADURO
  • EP3559553B1 patent drawingFigure 1~2
  • EP3559553B1 patent drawingFigure 3~4
  • EP3559553B1 patent drawingFigure 5~6

AI summary

Disclosed is a combi stove (1)arranged for combusting both logs and granular material. The combi stove (1)comprises a common combustion chamber (2)arranged so that both the logs and the granular material may be combusted in the common combustion chamber (2). The combi stove (1)further comprises ash collecting means (3)arranged under the combustion chamber (2)and a front aperture (4)through which logs may be placed in the combustion chamber (2). Also the combi stove (1)includes a granular material combustion area (5)arranged in the combustion chamber (2), wherein the granular material combustion area (5)comprises a bottom combustion surface (6)including bottom airflow apertures (7)arranged to enable an airflow to the granular material during a combustion of the granular material in the granular material combustion area (5), wherein the granular material combustion area (5)is at least partly surrounded by a granular material area sidewall (8)comprising sidewall airflow apertures (9)arranged to enable an airflow to flue gasses generated during a combustion of the granular material in the granular material combustion area (5), and wherein at least a part of the granular material area sidewall (8)is releasable from the granular material combustion area (5). Furthermore, a use of a combi stove (1) is disclosed.