Exhaust Flue Cap Filter Device for Gas Appliances
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Solution Overview
Problem
Gas fired appliances emit carbon monoxide and particulate emissions, which existing venting systems fail to adequately reduce while maintaining efficient exhaust flow.
Innovation Solution
An exhaust flue cap and filter device with a catalytic filter insert that treats exhaust gases, allowing atmospheric air to assist in conversion of carbon monoxide and particulates, and includes a bypass mechanism for filter blockages, minimizing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a filter device is installed in the exhaust flue, then carbon monoxide and particulate emissions are reduced, but exhaust flow efficiency is reduced
Solution Approach 1:
The filter device utilizes a porous ceramic foam structure that allows exhaust gases to pass through while capturing particulates and enabling catalytic conversion of carbon monoxide. The porous nature maintains flow efficiency by providing numerous pathways for gas passage rather than a single restrictive filter medium.
Solution Approach 2:
The system changes the chemical parameters of exhaust gases by introducing atmospheric air to facilitate catalytic oxidation of carbon monoxide to carbon dioxide. This parameter change occurs within the filter structure without significantly impeding the physical flow of exhaust gases.
2Object-generated harmful factors
If a catalytic filter insert is used, then carbon monoxide conversion is improved, but device complexity increases
Solution Approach 1:
The filter device combines multiple functions into a single integrated component: mechanical filtration of particulates, catalytic conversion of carbon monoxide, and mixing with atmospheric air. This merging reduces overall system complexity compared to having separate devices for each function.
Solution Approach 2:
The filter insert serves multiple purposes simultaneously: it acts as a physical filter for particulates, a catalytic converter for carbon monoxide, and a mixing chamber for atmospheric air introduction. This multi-functionality eliminates the need for separate components for each emission control function.
3Object-generated harmful factors
If the filter component is blocked, then emission reduction is maintained, but exhaust flow is blocked
Solution Approach 1:
The system dynamically adapts to filter blockage conditions by automatically drawing in atmospheric air through side openings. This dynamic response ensures that even when the filter becomes blocked, exhaust gases can still pass through the device with reduced emission control efficiency but maintained flow capability.
Solution Approach 2:
The device incorporates atmospheric air intake openings that provide a backup pathway for exhaust flow in advance of complete filter blockage. This pre-configured alternative pathway cushions against total flow cessation by allowing gases to bypass a blocked filter media.
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
Reduces carbon monoxide emissions by 20-40% to 70% while maintaining flow efficiency and preventing rain ingress, with a minimal pressure drop observed during testing.
Implementation Method 1
The filter insert is catalytically active
Implementation Method 2
atmospheric air to assist in conversion of carbon monoxide
Data Source
Figure 1~3
Figure 4
AI summary
An exhaust flue cap and filter device (10) for a gas fired appliance in communication with an exhaust flue opening having an outer pipe (13) and a coaxial liner (14). The device includes a tubular cap (16) with an open lower end (18), an opposed open upper end (20), and a plurality of ventilation holes (22) wherein the cap is receivable over the flue opening. A removable top (24) is attached to and closes the open upper end of the tubular cap. A filter tray (40) having a smaller diameter than the tubular cap includes a ledge (44) extending radially inward from the tray. A removable catalytic converter filter insert (50) within the tubular cap is supported on the ledge.