Passive ductwork intumescent fire damper
Solution Overview
Problem
Existing fire dampers are complex, expensive, and unsuitable for small ductwork applications due to obstructions in the air stream, requiring access doors and periodic testing, which can lead to blockages and impaired operation.
Innovation Solution
A passive intumescent fire damper with a metal ductwork housing, a meltable plastic liner, and a metal-intumescent laminate assembly surrounded by heat shrink bands, which expands to close the duct when exposed to heat, eliminating the need for access doors and ensuring a smooth air stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fire dampers with access doors are used, then fire safety is ensured, but device complexity and installation cost increase
Solution Approach 1:
The invention removes the access door component from the fire damper system entirely. The fire damper is designed as a self-contained unit that can be installed in concealed locations without requiring maintenance access, thereby eliminating the complexity and cost associated with access doors while maintaining fire safety through the intumescent sealing mechanism
Solution Approach 2:
The fire damper is designed to be self-monitoring and self-actuating through the intumescent material that automatically expands when exposed to fire conditions, eliminating the need for manual access or external control systems. The device serves itself by using the fire heat to trigger the sealing action without requiring human intervention or access doors
2Reliability
If fusible link fire dampers are used, then fire protection is provided, but manufacturing cost and complexity increase
Solution Approach 1:
The invention replaces expensive fusible link mechanisms with a simpler intumescent material-based system. The intumescent material provides fire protection through a chemical expansion reaction that is more cost-effective to manufacture than mechanical fusible link systems, while achieving the same fire containment goal
Solution Approach 2:
The invention substitutes the mechanical fusible link system with a chemical-based intumescent material system. Instead of using mechanical components that melt and release blades, the patent uses intumescent material that expands chemically when heated to seal the duct, resulting in lower manufacturing costs and simpler construction
3Reliability
If conventional fire dampers with blades are used, then fire containment is achieved, but material buildup and blockage hazards occur
Solution Approach 1:
The invention removes the blade component from the fire damper design. By eliminating the physical blade that protrudes into the air stream, the patent prevents material buildup and blockage hazards while maintaining fire containment through the intumescent material that seals when expanded, creating a smooth duct interior
Solution Approach 2:
Instead of using a blade that moves to open or close the duct, the invention inverts the approach by using a material that expands to seal the duct when exposed to fire. The normal state is open with no obstruction, and the fire state triggers the sealing action, reversing the conventional approach where a blade is normally closed and must be forced open
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 simple, cost-effective, and efficient fire damper for small ductwork applications, preventing material buildup and ensuring superior airflow, while eliminating the need for annual inspections and access doors, making it suitable for concealed locations.
Implementation Method 1
The heat shrink tubing is then exposed to heat and as it shrinks it pulls the metal of the laminate assembly in radially, thereby creating a cone shape
Implementation Method 2
The intumescent material is then exposed to the inside of the ductwork and when exposed to the heat will expand and close off the duct passage
Implementation Method 3
The metal of the laminate assembly accelerates this process by conduction and ensures that the intumescent continues expansion
Implementation Method 4
the liner will melt. The heat shrink tubing is then exposed to heat
Data Source
AI summary
There is disclosed a passive intumescent fire damper having a metal housing, an inner meltable liner and having a metal and intumescent laminate assembly surrounding the inner liner.