Frangible Net Fire Protection for Composite Pressure Vessels
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Solution Overview
Problem
Current thermally-activated pressure relief devices (TPRDs) are not optimally designed to mitigate localized fires on longer fuel tanks, leading to potential tank ruptures, as they require excessive heat for activation and may not function if a fire occurs remotely, resulting in inadequate protection and increased costs due to the need for additional TPRDs and high-pressure piping.
Innovation Solution
A fire-activated frangible net system is proposed, comprising stretchable netting sections linked by fuse wires anchored to a TPRD, which initiates the relief valve when a localized fire triggers the system, allowing for immediate release of pressurized gas by releasing tension and activating the TPRD spool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If TPRDs are spaced far apart on longer tanks, then device complexity and cost are reduced, but fire protection reliability deteriorates because localized fires remote from TPRDs cannot activate the devices
Solution Approach 1:
The tank surface is segmented into multiple zones by positioning TPRDs at different locations, with each TPRD responsible for protecting its local zone. The frangible net system divides the protection function across multiple TPRD units, where each unit independently protects its sector through the frangible net mechanism.
Solution Approach 2:
The protection system transitions from one-dimensional linear spacing of TPRDs along the tank length to a three-dimensional coverage system using frangible nets that extend radially outward from the tank surface. This creates volumetric fire protection zones that capture localized fires in three-dimensional space rather than relying solely on linear TPRD spacing.
2Reliability
If additional TPRDs and high-pressure piping are added to ensure coverage, then fire protection reliability improves, but device complexity and cost increase
Solution Approach 1:
Multiple TPRD units are merged into a coordinated system where each TPRD is equipped with a frangible net. The frangible nets of adjacent TPRDs overlap to create continuous three-dimensional protection coverage, eliminating the need for additional high-pressure piping while maintaining reliable fire protection through the combined effect of multiple TPRD-net units.
Solution Approach 2:
The system uses frangible nets to extend protection into the three-dimensional space surrounding the tank, rather than relying solely on increasing the number of TPRDs along the tank surface. This volumetric approach provides comprehensive coverage with fewer TPRD units by creating overlapping protection zones in space.
3Reliability
If TPRDs are positioned to cover the entire tank length, then fire protection reliability improves, but weight and cost increase due to additional components
Solution Approach 1:
The frangible net structure provides three-dimensional fire protection coverage that extends radially from the tank surface, allowing TPRDs to be spaced farther apart while maintaining comprehensive protection. This spatial extension of protection zones reduces the number of TPRD units needed, thereby reducing the total weight of the fire protection system.
Solution Approach 2:
The tank protection is divided into multiple overlapping zones, each protected by a single TPRD with its frangible net. This segmentation allows TPRDs to be strategically positioned at intervals rather than continuously distributed, reducing the total number of TPRD units and their associated weight while maintaining full coverage through the extended frangible net protection zones.
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
This solution provides reliable, cost-effective, lightweight, and fast-acting three-dimensional fire protection for composite overwrapped pressure vessels, minimizing the risk of tank rupture from localized fires without the need for extensive additional TPRD placement, thereby enhancing safety and reducing costs.
Implementation Method 1
a localized fire triggers the system... when a localized fire burns it, the thermally-activated pressure relief device (TPRD) spool slides to the open position
Implementation Method 2
stretchable netting sections... The netting sections are slid over the tank like a sock or sleeve and/or wrapped around the tank
Implementation Method 3
fire-activated frangible net system... which initiates the relief valve when a localized fire triggers the system, allowing for immediate release of pressurized gas
Data Source
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AI summary
A localized fire protection system for composite overvvrapped pressure vessels which uses net or mesh which stretches in at least one direction. They can he elastomeric or polymeric or any material and/or weave that provides said function. Wrapping sections held together via a flammable fuse connected to a relief valve under pressure from the net wrappings to block a relief valve pathway to replace stored gas in case of a localized fire.