Pellet Stove Burner Airflow Layout for Ash-Free Combustion
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Solution Overview
Problem
The use of solid fuels like pellets and alternative fuels in stoves leads to ash and combustion product accumulation, obstructing air passage holes and causing irregular combustion, reduced thermal efficiency, and increased emissions of CO, NOx, and unburnt products due to suboptimal air distribution.
Innovation Solution
A burner design with a motor-driven spatula for removing burnt products, combined with 'V' or 'U' shaped secondary air distributor elements that optimize the ratio of primary to secondary air, ensuring efficient combustion by directing secondary air through curved metal or ceramic elements, while primary air enters centrally through the brazier surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a square or rectangular fuel collection tank with vertical walls is used, then the construction is simple and manufacturing is easy, but ash and combustion products become stagnant at the base edges, obstructing air passage holes and causing irregular combustion
Solution Approach 1:
The patent applies asymmetry by providing a spheroidal portion at the bottom of the fuel collection tank. This spherical element creates asymmetric airflow patterns and turbulence that prevent ash stagnation at the base edges, while the overall tank structure remains simple and easy to manufacture. The spherical portion acts as a flow disruptor that maintains combustion regularity without complicating the basic tank construction.
Solution Approach 2:
The patent introduces a spheroidal portion at the bottom of the tank to replace the traditional flat or angular bottom design. This curved surface promotes better airflow distribution and prevents ash accumulation in corners and edges, thereby maintaining air passage hole openness and ensuring regular combustion while keeping the construction relatively simple.
2Ease of manufacture
If alternative fuels such as processing residues, cereals and vegetal waste are used, then production costs are reduced and fuel availability is improved, but these fuels produce melting substances that form solid layers on the brazier base, obstructing air passage holes and extinguishing the flame
Solution Approach 1:
The spheroidal portion at the tank bottom creates continuous airflow turbulence that prevents melting substances from forming continuous solid layers. The curved geometry promotes ash and residue movement, preventing them from blocking air passage holes, thereby maintaining combustion continuity when using alternative fuels that produce melting byproducts.
Solution Approach 2:
The spheroidal portion induces mechanical turbulence and vibration in the airflow and ash movement. This continuous agitation prevents the formation of stable solid layers on the brazier base, keeping air passage holes open and ensuring uninterrupted combustion when using alternative fuels that tend to produce melting residues.
3Reliability
If primary air is distributed through the entire burner surface, then combustion is maintained across the whole area, but the ratio between secondary air and primary air is suboptimal, increasing emissions of CO, NOx and unburnt products
Solution Approach 1:
The patent applies local quality by concentrating primary air supply at the central spheroidal portion rather than distributing it uniformly across the entire burner surface. This localized air injection creates optimal primary air-to-fuel mixing at the combustion zone, while secondary air is introduced separately to achieve the correct overall air ratio, thereby reducing harmful emissions while maintaining combustion stability.
Solution Approach 2:
The patent segments the air supply system into distinct primary and secondary air pathways. Primary air is introduced through the central spheroidal portion, while secondary air is supplied through separate channels. This segmentation allows independent optimization of each air stream, achieving both stable combustion and low emissions by controlling the precise ratio between primary and secondary air.
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
This design significantly reduces combustion emissions and unburnt products, improves thermal efficiency, and maintains the simplicity of construction and functionality.
Implementation Method 1
the turbulence action caused by the blown air is weaker
Implementation Method 2
it is taken, generally by a screw, to be gradually laid in the burner
Implementation Method 3
a burner (1) for a stove fuelled with solid fuels... provided with a fuel collection tank (27) having a pierced bottom wherethrough the comburent air enters the combustion chamber (2)
Data Source
Figure 1~2
Figure 3~6
Figure 7~9
AI summary
This is a burner for a stove fuelled with solid fuels, in particular pellet, wherein there is provided a brazier (1) with a substantially rectangular shape whereon a device acts for removing the burnt product consisting of a motor-driven spatula (6) provided with a pivoting movement, which has the function of keeping, the brazier holes free from burnt product. Such burner is characterised in that it exhibits, at the centre line thereof in longitudinal direction, a portion thereof provided with upwards facing concavity and subject to the action of the spatula, Such portion is provided with through holes wherethrough the primary air required for combustion flows outwards. On the other hand, the secondary air flows through the holes (12) obtained in a pair of elements (11) obtained by a metal sheet, which are curved substantially as a V, with upward facing apex, or as an upturned "U", according to the combustion power of the burner.