Low-Profile Termination Cap with Air Wash for Direct Vent Appliances
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Solution Overview
Problem
Current termination caps for direct vent appliances are large, bulky, and aesthetically unpleasing, often extending beyond the exterior wall and violating local regulations due to their size and appearance, while also failing to effectively protect the surrounding structure from damage caused by recirculated exhaust gases.
Innovation Solution
A termination cap design featuring a flared outer housing with an offset exhaust body and a trim plate that includes combustion air openings and an exhaust gas opening, allowing heated combustion air to rise and create an air wash along the wall surface, deflecting exhaust gases away from the structure and reducing the cap's exterior profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional termination cap is used, then exhaust gases are discharged and protected from recirculation, but the cap becomes large and bulky extending beyond the wall
Solution Approach 1:
The exhaust body is nested within the outer housing, with the exhaust body having an outer surface offset from the inner housing inner surface to form a combustion air passageway. This nested configuration allows the termination cap to maintain protective functions while reducing its overall external dimensions and extending less beyond the wall.
Solution Approach 2:
The invention utilizes the radial dimension by offsetting the exhaust body outer surface from the inner housing inner surface, creating a three-dimensional combustion air passageway. This dimensional approach allows combustion air to flow around the exhaust body, enabling a more compact overall structure that protects against exhaust recirculation without requiring excessive extension beyond the wall.
2Reliability
If a larger termination cap is used, then exhaust gas discharge is more effective, but the cap becomes aesthetically unpleasing and may violate local regulations
Solution Approach 1:
The nested configuration of the exhaust body within the outer housing creates a compact, streamlined appearance. The offset surfaces form a combustion air passageway that is integrated into the overall structure, eliminating the need for bulky external components while maintaining effective exhaust gas discharge through the concentrated exhaust opening.
Solution Approach 2:
The invention concentrates the exhaust gas discharge function into a specific localized opening in the trim plate, while the surrounding structure provides aesthetic coverage. The combustion air openings are strategically positioned in the trim plate sides, allowing functional requirements to be met with a visually pleasing, compact exterior profile.
3Shape
If the termination cap is mounted flush with the wall, then aesthetics improve, but exhaust gases may contact and damage the wall surface
Solution Approach 1:
The combustion air passageway acts as an intermediary barrier between the exhaust body and the outer housing. Combustion air flows through this passageway, creating a protective air layer that prevents direct contact between hot exhaust gases and the wall surface, enabling a flush-mounted configuration that protects both aesthetics and wall integrity.
Solution Approach 2:
The invention converts the potentially harmful hot exhaust gases into a beneficial heating function. The exhaust body heats the combustion air that flows through the combustion air passageway, and this heated air rises and exits through combustion air openings in the trim plate, creating a protective air wash that prevents exhaust gas contact with the wall while utilizing the thermal energy constructively.
4Object-affected harmful factors
If combustion air is drawn through side openings, then air wash protection is created, but heating of the air is required to make it rise
Solution Approach 1:
The invention converts the thermal energy of the exhaust gases, which would otherwise be wasted heat, into a useful function by using it to heat the combustion air in the combustion air passageway. This heated air becomes less dense and rises, creating a protective air wash that flows over the wall surface and prevents exhaust gas recirculation and wall damage.
Solution Approach 2:
The exhaust body serves a dual function: it discharges exhaust gases through the exhaust opening while simultaneously heating the combustion air that flows through its surrounding passageway. The system is self-sufficient, using its own thermal output to create the protective air wash effect without requiring external energy input.
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 provides a slimmer, more aesthetically pleasing termination cap that effectively protects the building surface from exhaust gases, reducing the risk of damage and compliance with local regulations by creating an air wash that insulates the wall from high-temperature exhaust gases, while maintaining efficient exhaust gas discharge.
Implementation Method 1
combustion air passing through the combustion air openings contacts the exterior surface of the exhaust body, wherein combustion air drawn through the combustion air openings in the one or more side portions of the trim plate is heated by the exhaust body causing a portion said air to rise within the combustion air passageway
Implementation Method 2
air exiting the said one or more combustion air openings creating an air wash along a surface of a wall of a structure within which the termination cap is mounted to help protect the surface from damage from contact with exhaust gases
Data Source
AI summary
A termination cap for a direct vent appliance. The termination cap comprises an outer housing, an exhaust housing nested within the outer housing and a trim plate. The trim plate has an exhaust gas opening and combustion air openings and is securable to the exhaust body to allow exhaust gas to flow through the exhaust gas opening. At least a portion of the combustion air drawn through the combustion air openings is heated and exits through the top or upper portion of the trim plate to form an air wash along the wall surface within which the cap is mounted.