Flow Limiting Duct Vent Valve Overpressure Shutoff
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Solution Overview
Problem
Conventional duct vent valves in gas turbine engine bleed air systems are easily overpowered by elevated bleed air leakage, leading to inefficient energy use, increased heat exposure of components, and reduced fault detection reliability due to their lack of overpressure shutoff functionality.
Innovation Solution
A flow limiting duct vent valve with an overpressure shutoff function that automatically opens to vent pressurized air at lower duct pressures and closes at higher pressures to prevent excessive airflow extraction, reducing heat exposure and aiding fault detection by creating a detectable pressure spike.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional duct vent valve is used to vent bleed air from the Y-duct, then pressure relief is provided to prevent undesirable pressure build-up, but the valve is easily overpowered by elevated bleed air leakage leading to inefficient energy use and increased heat exposure of components
Solution Approach 1:
The patent changes the operational parameters of the duct vent valve by introducing a flow limiting mechanism that modifies the valve's opening characteristics. The valve now operates with a controlled opening degree rather than fully open, changing the flow parameters to limit excessive airflow while maintaining pressure relief functionality. This resolves the contradiction by allowing pressure relief while preventing energy waste from excessive venting.
Solution Approach 2:
The patent implements a feedback mechanism where the duct vent valve's operation is continuously adjusted based on the pressure differential across it. The valve monitors the pressure conditions and automatically modulates its opening degree to maintain optimal pressure relief while preventing over-venting. This feedback control resolves the contradiction by dynamically balancing pressure relief needs against energy conservation.
2Reliability
If a conventional duct vent valve remains open to vent bleed air, then pressure build-up is prevented, but components experience increased heat exposure
Solution Approach 1:
The patent applies partial action by having the duct vent valve open only to the extent necessary for pressure relief rather than remaining fully open. The flow limiting mechanism ensures the valve opens partially to provide sufficient pressure relief while limiting the excessive airflow that causes heat exposure. This resolves the contradiction by providing just enough venting to prevent pressure build-up without the excessive action that causes thermal damage.
3Reliability
If a conventional duct vent valve is equipped with overpressure shutoff functionality, then fault detection reliability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the overpressure shutoff functionality with the existing duct vent valve structure. The flow limiting mechanism and overpressure shutoff feature are integrated into a single valve assembly rather than being separate components. This merging resolves the contradiction by providing enhanced fault detection reliability while minimizing the increase in device complexity through integrated design.
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
Improves gas turbine engine efficiency by reducing parasitic air extraction, prolongs component lifespan, and enhances fault detection by generating a distinct pressure signal for maintenance.
Implementation Method 1
the valve element moves from: (i) the closed position to an open vent position when the pressure differential across the valve element exceeds a first threshold
Implementation Method 2
the valve element moves from: (ii) from the open vent position to an overpressure shutoff position when the pressure differential across the valve element exceeds a second threshold greater than the first threshold
Data Source
AI summary
Embodiments of a flow limiting duct vent valve (DVV) are provided, as are embodiments of a bleed air system including a flow limiting DVV. In one embodiment, the bleed air system a flow limiting DVV and a first valved device, such as a high pressure regulator. The DVV includes, in turn, a housing assembly having an inlet and an outlet. The inlet is fluidly coupled to the valved device when the bleed air system is installed on a gas turbine engine. A valve element is mounted in the housing assembly and, during operation of the DVV, moves from: (i) the closed position to an open vent position when the pressure differential across the valve element exceeds a first threshold, and (ii) from the open vent position to an overpressure shutoff position when the pressure differential across the valve element exceeds a second threshold greater than the first threshold.