Non-bypassable catalyst assisted appliances

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Solution Overview

Problem

Conventional catalytic wood stoves often require a bypass mechanism to prevent air flow restriction during startup or loading, leading to potential 'dirty burn' modes that can result in increased emissions and operational inefficiencies.

Innovation Solution

A non-bypassable catalyst assisted appliance design featuring a catalytic combustor optimized in size and configuration to maintain a clean burn mode without restricting air flow, eliminating the need for a bypass mechanism by ensuring gas and ambient air pass through the combustor regardless of the loading door position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bypass mechanism is added to allow air flow during loading, then ease of operation is improved, but device complexity increases and reliability of clean burn mode deteriorates

Engineering Contradiction:
Improveease of operationVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The bypass mechanism is completely removed from the system. The patent eliminates the bypass door and associated handle that were present in conventional catalytic wood stoves, simplifying the device structure while maintaining ease of operation through a single door design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of providing a bypass path around the catalyst combustor when the door is open, this invention inverts the approach by designing the combustor itself to accommodate open-door operation. The combustor is sized and configured to handle the increased air flow directly, reversing the conventional wisdom that required bypassing the catalyst during loading.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If a bypass mechanism is added to allow air flow during loading, then ease of operation is improved, but reliability of clean burn mode deteriorates

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bypass mechanism is completely removed from the system. The patent eliminates the bypass door and associated handle that were present in conventional catalytic wood stoves, simplifying the device structure while maintaining ease of operation through a single door design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The catalyst combustor continuously processes all air flow and combustion gases regardless of door position. By eliminating the bypass, the system ensures continuous catalytic action on all exhaust gases, maintaining reliable clean burn mode operation whether the door is open or closed.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If catalyst combustor size is reduced to improve heat output, then productivity is improved, but air flow restriction increases causing dirty burn mode

Engineering Contradiction:
ImproveproductivityVSAvoidemissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the key parameters of the catalyst combustor including its size, cell density, and flow velocity characteristics. By optimizing these parameters, the combustor maintains high productivity while preventing air flow restriction that would lead to dirty burn mode and increased emissions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The combustor design accommodates dynamic air flow conditions that occur when the door is open during loading. The system is designed to handle variable flow rates and velocities, adjusting to maintain efficient combustion and low emissions regardless of operational state.

Inventive Principle:
Principle #15Dynamics

4Object-generated harmful factors

If higher flow velocities are achieved through optimized combustor design, then emissions are reduced, but particulate accumulation increases

Engineering Contradiction:
ImproveemissionsVSAvoidparticulate accumulation
Core Design Contradiction:
Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The patent optimizes the combustor parameters including cell density, flow velocity, and residence time to achieve a balance where emissions are reduced through efficient catalytic conversion while particulate accumulation is minimized through controlled flow characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system operates with periodic variations in flow velocity and temperature that prevent excessive particulate buildup. The natural cycling of combustion intensity and air flow creates conditions that periodically clear accumulated particulates, extending maintenance intervals.

Inventive Principle:
Principle #19Periodic action

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 maintains a clean burn mode passively, reducing emissions and operational inefficiencies, and allows for higher flow velocities through the combustor, minimizing particulate accumulation and extending maintenance intervals.

Implementation Method 1

A catalyst combustor is disposed between the combustion chamber and the exit opening

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3535522B1Non-bypassable catalyst assisted appliances
Publication Date: 2023.05.31 JOETUL
  • EP3535522B1 patent drawingFigure 1~2
  • EP3535522B1 patent drawingFigure 3~4
  • EP3535522B1 patent drawingFigure 5

AI summary

A non-bypassable catalyst assisted appliance (100, 1000) includes, for example, a housing (112, 1112) having a combustion chamber (300, 1300) therein. The housing has a loading door opening (117, 1117) coverable by a door (116, 1116) for loading fuel into the combustion chamber, an air inlet opening (111, 1113, 1115) for receiving an air supply to the combustion chamber, and an exit opening (118, 1118) connectable to a flue (119, 1119). A catalyst combustor (200, 1200) is disposed between the combustion chamber and the exit opening. When the door of the non-bypassable catalyst assisted appliance is disposed in a closed position covering the loading door opening, gas from the combustion chamber is directed through the catalyst combustor, and out the flue. When the door of the non-bypassable catalyst assisted appliance is disposed in an open position allowing loading of fuel through the loading door opening to the combustion chamber, ambient air entering the loading door opening and gas from the combustion chamber are directed through the catalyst combustor, and out the flue.