Aerated Foam Nozzle Layout for Large Tank Surface Fire Coverage
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Solution Overview
Problem
Existing fixed systems for fighting fires in large industrial tanks are costly, unreliable, and ineffective in extinguishing full surface liquid tank fires, especially in tanks over 100 feet in diameter, due to limitations in foam expansion and projection capabilities.
Innovation Solution
Development of a fixed system using aerated foam nozzles with a stream shaper that projects foam in a focused stream, capable of expanding between 2-to-1 to 8-to-1, allowing for efficient coverage of larger tank surfaces with fewer units, and incorporating a third nozzle to project foam towards the center of the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional foam chambers or foam pourers are used around the tank perimeter, then rim seal fires can be addressed, but the system is costly and requires many units spaced every 40-80 feet
Solution Approach 1:
The system divides the tank protection into two functional segments: perimeter foam chambers for rim seal fires and central nozzles for full surface fires. This segmentation allows each component to be optimized for its specific purpose, reducing the overall number of units needed while maintaining comprehensive coverage
Solution Approach 2:
The invention adds a vertical dimension by projecting foam upward and inward from central nozzles mounted on the tank roof, rather than only horizontal discharge from perimeter chambers. This three-dimensional foam projection covers the central tank surface area that would otherwise require additional perimeter units
2Speed
If foam is highly aerated for rapid spread, then foam run distance increases, but foam losses due to wind and thermal updraft increase
Solution Approach 1:
The system applies different foam aeration levels to different tank zones: highly aerated foam (6:1 to 12:1 expansion) is used for perimeter application where rapid spread along the rim seal is needed, while less aerated foam (3:1 to 6:1 expansion) is used for central projection where wind and thermal updraft losses are more significant
Solution Approach 2:
The system dynamically adjusts foam expansion ratio based on application location and fire type, changing the aeration parameter to optimize performance for each specific condition rather than using a single fixed aeration level throughout
3Area of stationary object
If more foam chambers are installed to cover larger tank surfaces, then coverage area increases, but system cost and complexity increase
Solution Approach 1:
The invention merges the functions of multiple perimeter foam chambers with central roof-mounted nozzles into a coordinated system. The central nozzles project foam inward to cover the central tank surface, replacing the need for additional perimeter chambers that would otherwise be required to achieve the same coverage area
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 system effectively extinguishes larger tank fires with fewer units, achieving a wider and more rapid foam run, reducing the number of installations required and enhancing safety by minimizing personnel risk.
Implementation Method 1
at least one aerated foam nozzle in fluid communication with and located proximate to and downstream of an ambient air aeration chamber. The nozzle and aeration chamber are structured together for producing aerated foam
Implementation Method 2
The nozzle preferably has a stream shaper in its tip and is affixed to the tank so as to discharge a substantially focused stream roughly horizontally along an upper inner tank wall portion
Data Source
AI summary
Fixed systems and method for extinguishing large scale industrial tank fires, with and without fixed roofs, and featuring aerated foam projecting nozzles and including fixed center directed nozzles.