Fire Extinguishing Valve Control for Enclosed Space Rekindling Prevention
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Solution Overview
Problem
Fire extinguishing systems in enclosed spaces, such as aircraft, face shutdown due to super-cooling of pressure reducers and contamination accumulation, which can lead to rekindling of fires, and rely on potentially environmentally harmful halon agents.
Innovation Solution
A system with a controllable flow control valve, connected to a control unit monitoring temperature and pressure, allows unthrottled initial discharge of fire extinguishing agent to suppress fires and intermittent discharge to maintain minimal concentrations, avoiding the use of pressure reducers and preventing rekindling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure reducer is used to throttle the extinguishing agent flow, then the extinguishing agent concentration can be maintained to prevent rekindling, but the system shuts down due to super-cooling and contamination accumulation
Solution Approach 1:
The patent removes the pressure reducer component from the system entirely. Instead of using a pressure reducer to throttle flow, the system uses a controllable valve (3) that can be opened or closed based on sensor feedback, eliminating the source of super-cooling and contamination accumulation while maintaining reliable operation
Solution Approach 2:
The patent implements a feedback control system using temperature sensor (20) and pressure sensor (21) that monitor conditions and signal the control unit (4) to operate the controllable valve (3). This feedback mechanism maintains extinguishing agent concentration without requiring a pressure reducer, preventing the harmful effects of super-cooling and contamination
2Reliability
If halon fire extinguishing agents are used, then fire suppression effectiveness is achieved, but environmental harm increases due to ozone layer damage
Solution Approach 1:
The patent changes the chemical composition parameter of the fire extinguishing agent from halon to alternative agents such as nitrogen, carbon dioxide, or clean agent formulations. This parameter change maintains fire suppression effectiveness while eliminating the environmental harm associated with ozone depletion
3Speed
If unthrottled discharge is used to rapidly suppress fire, then initial concentration is achieved quickly, but system complexity increases with control requirements
Solution Approach 1:
The patent segments the discharge process into two distinct phases: an initial unthrottled discharge phase for rapid fire suppression, and a subsequent controlled phase using the controllable valve for maintaining concentration. This segmentation allows quick response while managing system complexity through clear operational stages
Solution Approach 2:
The system performs preliminary unthrottled discharge to quickly achieve the required extinguishing agent concentration and suppress the fire. This preliminary action occurs before the controllable valve is activated, allowing rapid response while the control system prepares for the maintenance phase
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
Ensures reliable fire suppression and prevention of rekindling without system shutdown, using environmentally friendly fire extinguishing agents and reducing contamination issues, thereby enhancing the safety and efficiency of firefighting in enclosed spaces.
Implementation Method 1
Due to the high pressure drop of the extinguishing agent downstream of the pressure reducer, the extinguishing agent changes from its liquid phase into its gaseous phase.
Data Source
AI summary
A system for fighting a fire in an enclosed space has at least one container (3) for holding a fire extinguishing agent under pressure. A pipe system connects a container outlet to a discharge in the enclosed space. A controllable flow control valve (5) in the pipe system is responsive to a flow control signal generated by a control unit (4) in response to sensed characteristics (pressure and/or temperature) of the agent. A trigger action initially opens the container to the pipe system. The valve is initially held open until concentration (A) of fire extinguishing agent in the enclosed space is sufficient to suffocate a started fire. Thereafter, the valve is opened intermittently to maintain a lower concentration of fire extinguishing agent in the space sufficient to prevent rekindling. More than one container may be used but only one is equipped with a valve controllable by a control unit.