Intumescent Duct Fire Damper for Small Horizontal Wall Vents
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Solution Overview
Problem
Existing fire dampers are complex, expensive, and unsuitable for small ductwork applications due to blockage hazards and material buildup, requiring periodic testing and access issues, especially in environments like kitchen exhaust and bathroom ventilation.
Innovation Solution
A passive intumescent fire damper with a simple design comprising a sheet metal box, ceramic sheet lining, L-shaped intumescent, sheet metal comb, plastic liner, sheet metal comb catch, and escutcheon, which is easy to install and use, and effective in small ductwork applications like kitchen range hood installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dynamic or standard fire dampers are used, then fire protection function is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and removes the complex mechanical testing and actuation mechanisms from traditional fire dampers. Instead of using dynamic blades, springs, and testing mechanisms, the invention uses a simple passive intumescent strip that automatically expands when exposed to fire heat, eliminating the need for periodic testing and complex mechanical components while maintaining fire protection function.
Solution Approach 2:
The patent employs an inexpensive intumescent strip as a single-use, non-reusable component. Once the strip expands during a fire event, it permanently blocks the duct opening. This disposable approach eliminates the need for expensive mechanical dampers that require periodic testing, maintenance, and potential replacement of mechanical components.
2Reliability
If traditional fire dampers with access doors are used, then fire protection is achieved, but ease of installation and access is reduced
Solution Approach 1:
The patent segments the fire damper into a modular insert that fits within an existing duct opening. The intumescent strip is installed as a separate component within the duct, allowing easy installation without requiring fire-rated access doors or complex integration into wall assemblies. This modular approach simplifies both installation and potential future access.
3Extent of automation
If fusible link fire dampers are used, then automatic fire response is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical fusible link system with a chemical-intumescent response mechanism. Instead of using metal links that melt at specific temperatures to release mechanical blades, the invention uses an intumescent strip that chemically expands when exposed to fire heat, automatically blocking the duct. This substitution eliminates complex mechanical linkages while maintaining automatic fire response.
4Reliability
If complex intumescent fire dampers are used, then fire protection is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent uses a thin, flexible intumescent strip that can be easily manufactured and installed. The strip is a simple flat component with intumescent coating on one side, eliminating the need for complex molded or formed intumescent structures. This thin-film approach significantly simplifies manufacturing while maintaining effective fire protection through the intumescent expansion property.
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 provides a cost-effective, easy-to-install fire damper that effectively contains fires in small ductwork systems by expanding intumescent materials to block airflow while allowing smoke and fumes to escape, addressing the limitations of existing fire dampers in small ductwork applications.
Implementation Method 1
L-shaped intumescent
Implementation Method 2
expanding intumescent materials to block airflow
Data Source
AI summary
A passive ductwork intumescent fire damper is disclosed having a sheet metal box; an intumescent; a sheet metal comb; a plastic liner; a sheet metal comb catch; and a sheet metal escutcheon. The fire damper is particularly useful in a structural wall ducted horizontally such as a side wall range hood installation.