Spherical-Ball Back Draft Damper for Airtight Ventilation Sealing
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Solution Overview
Problem
Existing self-sealing back draft dampers for ventilation systems, such as exhaust fans and extractor hoods, often suffer from gaps due to complex designs and precise dimension requirements, leading to unwanted backflow of air and odors into ventilated rooms.
Innovation Solution
A self-sealing back draft damper featuring a conical tapered tube with a spherical closing member that self-positions at the narrow end to create an airtight seal, eliminating the need for precise part adjustments and allowing for easy mounting and increased airflow without additional parts or extensive dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional butterfly valves, throttle valves, or slats are used as back draft dampers, then the device structure is simple, but gaps appear between movable parts and nonmoving sections leading to air backflow
Solution Approach 1:
The patent employs a spherical closing member (ball) that rolls within a curved duct to seal against a ring-shaped seat. The spherical geometry enables the ball to conform to the curved duct walls and create an airtight seal without requiring precise dimensional adjustments or complex gasket systems. The curvature of the duct and the spherical shape of the closing member work together to eliminate gaps that plague conventional flat-valve designs.
Solution Approach 2:
The ball closing member is designed to self-seal by rolling to a specific position where it contacts the ring-shaped seat. The system uses the natural movement of the ball within the curved duct to achieve sealing without requiring additional adjustment mechanisms, gaskets, or complex assembly procedures. The ball automatically finds its sealing position based on the duct geometry and airflow conditions.
2Reliability
If a ball is used as a closing member in a curved duct with a ring-shaped seat, then sealing is improved, but the ball movement may be obstructed if the duct is deformed or impurities are present
Solution Approach 1:
The spherical closing member is specifically designed to roll smoothly within the curved duct geometry. The spherical shape naturally accommodates minor duct deformations and allows the ball to navigate around impurities by rolling over or around them rather than getting stuck. The curved duct design guides the ball's movement path, ensuring it reaches the sealing position even when the duct is not perfectly formed.
3Reliability
If the ball fits tight into the duct to provide a tight seal, then sealing is improved, but the movement of the ball could be obstructed or fully blocked
Solution Approach 1:
The duct is designed with different dimensional characteristics at different locations: the duct diameter is larger than the ball diameter at the inlet and along the movement path to ensure free ball movement, while a ring-shaped seat is positioned at the sealing location to provide the necessary contact for airtight sealing. This local variation in geometry allows the ball to move freely during operation while still achieving a tight seal when needed.
4Reliability
If additional parts with complicated shapes or specially formed edges and gaskets are used, then sealing is improved, but the dimensions of the ball and duct have to be precisely adjusted and production and mounting become more demanding
Solution Approach 1:
The invention eliminates the need for complicated shaped parts, specially formed edges, and multiple gaskets by using a simple spherical closing member that rolls within a curved duct. The sealing is achieved through the geometric relationship between the spherical ball and the curved duct with its ring-shaped seat, requiring no precise dimensional adjustments or complex assembly procedures. This dramatically simplifies both production and mounting while maintaining effective sealing.
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 solution effectively prevents backflow of odors and humidity while allowing self-initiated ventilation, ensuring a reliable and cost-effective airtight seal for extended periods without complex mounting requirements.
Implementation Method 1
The weight of the spherical closing member and the slope of the tapered tube are such that in absence of airflow in the direction to the exit opening of the valve, the closing member is self-positioned at the conical tapered inlet
Implementation Method 2
the spherical closing member can overcome the inclination on its path and is away from the inlet under force directed to the vent resulting from a pressure difference appearing between the exit openings and the inlet
Implementation Method 3
The continuous increase of the diameter of the conical tapered tube along its axis enables the free movement of the spherical closing member within the tube's entire volume
Data Source
AI summary
A self-sealing back draft damper for fully stopping backflow air through exhaust fans and extractor hoods. Contains a housing (1), with exit openings (2) and can have at least one mounting hole (10). Inside the housing (1) at least one inclined relative to the horizontal plane conical tapered tube (3) is airtightly fixed at its lower positioned narrow end to the hole (10), forming the conical tapered inlet (6) of the damper. Apertures are available on the tube part inside the housing. The tube (3) contains a spherical closing member (5) freely movable inside it, which closes the conical tapered inlet (6) and opens it when pushed away by airflow in direction to the vent. The axis of the tapered tube (3) can be also vertically oriented. The damper is airtightly attached preferably to the entrance of a fan, to the exhaust of an extractor hood or a vent.