Oxygen Pressure Relief And Ventilation For Regulator Failure
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Solution Overview
Problem
Aircraft oxygen systems face risks of damage and fire due to unregulated high-pressure oxygen release from failed pressure regulators, with minimal safety mechanisms to mitigate these risks.
Innovation Solution
A backup system comprising flow fuses and pressure relief valves, coupled with a ventilation pathway, to isolate and vent high-pressure oxygen and dilute concentrated oxygen in unpressurized compartments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure regulator is used to control oxygen flow, then oxygen pressure is regulated, but the system becomes vulnerable to regulator failure causing unregulated high-pressure release
Solution Approach 1:
The flow fuse is pre-installed in the oxygen line upstream of the regulator outlet. Upon regulator failure, the excessive pressure automatically triggers the flow fuse to close, preventing unregulated high-pressure oxygen from reaching downstream components. This preliminary protective mechanism activates automatically without requiring additional control systems.
Solution Approach 2:
The flow fuse acts as an intermediary safety device between the pressure regulator and downstream components. It monitors pressure conditions and intervenes by closing the oxygen flow when regulator failure causes excessive pressure, thereby protecting downstream equipment from damage while maintaining normal operation under regulated conditions.
2Reliability
If pressure relief valves are added to vent excess pressure, then pressure is relieved, but concentrated oxygen in the unpressurized compartment creates fire risk
Solution Approach 1:
The ventilation pathway serves as an intermediary system that connects the unpressurized compartment to the pressurized compartment. When the pressure relief valve vents excess oxygen into the unpressurized compartment, the ventilation pathway automatically activates to dilute the concentrated oxygen by introducing air from the pressurized compartment, thereby eliminating fire risk while maintaining pressure relief functionality.
Solution Approach 2:
The harmful concentrated oxygen is extracted from the unpressurized compartment through the ventilation pathway and replaced with diluted air mixture from the pressurized compartment. This separation and replacement process removes the fire hazard while preserving the pressure relief function.
3Reliability
If flow fuses are used to block downstream flow on regulator failure, then downstream components are protected, but the system complexity increases
Solution Approach 1:
The flow fuse is designed as a self-actuating device that automatically closes in response to excessive pressure from regulator failure without requiring external control signals or additional complexity. The system protects downstream components through this single, simple, self-service mechanism that fails safely by default.
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
Prevents damage to downstream components and reduces fire risk by isolating high-pressure oxygen and ventilating to safe oxygen concentrations, enhancing safety and reliability of aircraft oxygen systems.
Implementation Method 1
ventilating the unpressurized compartment with air from an occupied compartment via a pathway for diluting an oxygen concentration in the unpressurized compartment
Implementation Method 2
ventilating the unpressurized compartment with air from an occupied compartment via a pathway for diluting an oxygen concentration
Data Source
AI summary
An oxygen pressure relief and ventilation system includes a flow fuse fluidly coupled downstream of a pressure regulator. The pressure regulator is operatively coupled to an oxygen tank, and the oxygen tank is located in an unpressurized compartment of an aircraft. A pressure relief valve is fluidly coupled downstream of the flow fuse. A ventilation pathway fluidly couples the unpressurized compartment with a pressurized compartment. The flow fuse and the pressure relief valve are configured to cooperatively mitigate downstream flow of pressurized oxygen if the pressure regulator fails. The ventilation pathway is configured to allow air from the pressurized compartment to pass through to the unpressurized compartment for diluting a concentrated oxygen in the unpressurized compartment.