Heating Device Ash Collection and Flue Gas Outlet Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heating devices suffer from ash accumulation in heat exchangers and chimney due to unburned ash particles being carried by flue gases, leading to reduced efficiency and clogging.
Innovation Solution
The flue gas outlet is positioned near the top of the secondary fire chamber, creating an ash collection space, and deflector means, such as a truncated cone-shaped metal sheet, are used to recycle ashes back into the flames for complete burning. Additionally, a coiled tube heat exchanger with counter-flow design captures any escaped ash particles through condensation, and air feed channels distribute air tangentially to ensure uniform burning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the flue gas outlet is positioned near the bottom of the secondary fire chamber to facilitate ash removal, then ash extraction is improved, but unburned ash particles are carried into the heat exchanger causing clogging and reduced efficiency
Solution Approach 1:
The flue gas outlet is repositioned from the bottom to the top of the secondary fire chamber, changing the spatial dimension of ash- flue gas separation. This vertical positioning allows gravity to naturally separate ash particles from the flue gas stream, with ash falling to the bottom while clean flue gas exits from the top, eliminating heat exchanger clogging without compromising ash removal capability
Solution Approach 2:
The secondary fire chamber is functionally segmented into an upper flue gas outlet zone and a lower ash collection zone. This segmentation creates distinct functional areas: the upper region for clean flue gas extraction and the lower region for ash accumulation, allowing simultaneous achievement of both clean flue gas flow and easy ash removal
2Reliability
If the flue gas outlet is positioned near the top of the secondary fire chamber to prevent ash exit, then heat exchanger clogging is reduced, but ash collection and recycling capability is improved
Solution Approach 1:
A feedback mechanism is implemented where ashes collected in the ash collection space are actively recycled back into the combustion zone. The system monitors ash accumulation and uses deflector means to redirect ashes back into the flame path, creating a closed-loop feedback system that ensures complete combustion while maintaining clean flue gas output
Solution Approach 2:
Instead of simply discarding ashes that fall to the bottom of the secondary fire chamber, the system recovers them by implementing an ash recycling mechanism. Deflector means redirect unburned ash particles back into the combustion zone for further burning, converting what would be waste into additional energy while preventing heat exchanger clogging
3Productivity
If deflector means are added to recycle ashes back into flames, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The deflector means are designed to utilize the natural flow dynamics and turbulence of the flue gas and flame system itself to recycle ashes. The deflectors are strategically positioned to leverage existing gas flows, eliminating the need for additional active components or complex control systems, thereby achieving ash recycling through passive, self-service mechanisms
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 configuration minimizes ash exit through the flue gas outlet, ensures complete ash burning, and maintains heat exchanger efficiency by recycling ashes and capturing stray particles, resulting in improved combustion and reduced maintenance.
Implementation Method 1
Because the flames and combustion gases will cause turbulence, ashes dropped in the collection space will be picked up and recycle into the flames
Implementation Method 2
The heat exchanger is preferably of the counter flow type. As the heatable medium, typically water, is relative cold
Implementation Method 3
condensation will occur in the flue gases on the heat exchanger. This has the advantage that small ash particles, which managed to escape the secondary fire chamber through the flue gas outlet, are captured by the condensation droplets
Implementation Method 4
the air feed inlet channels have a tangential directional component at the exit into the primary fire chamber in order to urge the air into a vortex
Implementation Method 5
the plate will direct stirred up ashes back into the flames, creating a kind of whirlpool in which the ashes are recycled and further burned
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Heating device comprising: - a primary fire chamber (2) for burning a fuel (F), such as wood, the primary chamber having an air inlet (7) and a flame outlet (14); - a secondary fire chamber (3) with a flame inlet (10) at the top of the chamber and a flue gas outlet (14); - air circulation means (18) for feeding air into the air inlet of the primary fire chamber wherein the secondary fire chamber is below the primary fire chamber with respect to the direction of gravity, wherein the flue gas outlet is arranged at a distance from the bottom (12) of the secondary fire chamber such that an ash (11) collection space is provided between the bottom of the secondary fire chamber and the flue gas outlet.