Frangible Cable Fuse for Gas Turbine Emergency Fuel Shut-off
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Solution Overview
Problem
Existing emergency fuel shut-off systems for gas turbine engines suffer from significant time delays and high costs due to the need for cooling or heat shielding of sensors and electrical connections in the hot zone, as well as mechanical systems that require lengthy design and assembly processes.
Innovation Solution
An emergency fuel shut-off system that uses a fuse apparatus and cable assembly to transmit a mechanical actuation force from an actuator to a fuel shut-off device, which disables the force transmission when it exceeds a pre-selected level to prevent damage and ensure rapid shutdown without overstressing the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical shut-off system using a reference shaft co-axially associated with a turbine shaft is employed, then the fuel supply can be mechanically interrupted, but the system requires a relatively long time delay and results in more difficulties in the design and assembly of the engine
Solution Approach 1:
The patent extracts the actuator from the rotating reference shaft system and positions it on the stationary engine case. The actuator detects rotor shaft failure through vibration sensors and directly activates the fuel shut-off valve via a cable, eliminating the need for mechanical coupling through rotating reference shafts and thereby reducing time delay and design complexity
Solution Approach 2:
The patent introduces a cable as an intermediary element that transmits the mechanical actuation force from the actuator to the fuel shut-off valve. This cable-based transmission system replaces the complex mechanical linkage of co-axial reference shafts, achieving both rapid response and simplified design
2Measurement precision
If sensors and electrical connections are situated in the hot zone of the rotor shafts for electronic detection, then shaft failure can be detected, but high costs are incurred by the required cooling or heat shielding
Solution Approach 1:
The patent replaces the electronic sensor-based detection system with a mechanical actuator that responds to rotor shaft failure through mechanical means. The actuator is positioned outside the hot zone and transmits mechanical actuation force through a cable to the fuel shut-off valve, eliminating the need for expensive cooling or heat shielding of electronic components
Solution Approach 2:
The patent employs a simple cable-based transmission system that can be easily replaced if needed, rather than investing in expensive heat-resistant electronic components and cooling systems. The mechanical actuator and cable assembly provides a cost-effective alternative to electronic sensing in high-temperature zones
3Ease of manufacture
If a cable assembly is used to transmit mechanical actuation force, then the system becomes cost-effective and easier to manufacture, but the cable may transmit excessive force that could damage the fuel shut-off device
Solution Approach 1:
The patent incorporates a fuse apparatus as a pre-designed sacrificial element in the cable assembly. This fuse is positioned to break under excessive force, thereby protecting the fuel shut-off valve from damage while still allowing normal operation. The fuse acts as a predetermined weak point that sacrifices itself to prevent more serious damage to critical components
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 enables a rapid and cost-effective emergency fuel shut-off in gas turbine engines by allowing the system to actuate the fuel shut-off valve in response to rotor shaft failure while preventing damage to the valve and reducing manufacturing costs through a cable assembly that can be easily replaced.
Implementation Method 1
a cable linking the actuator with the fuel shut-off valve to transmit the mechanical actuation force from the actuator to the fuel shut-off valve
Implementation Method 2
the fuse apparatus being adapted to disable transmission of the mechanical actuation force in order to prevent damage to the fuel shut-off device when the transmitted mechanical actuation force exceeds a pre-selected level
Data Source
AI summary
An emergency fuel shut-off system for a gas turbine engine comprises a fuel shut-off device to be actuated for terminating a fuel supply to the engine in response to a mechanical actuation force and an actuator adapted for creating the mechanical actuation force when a rotor shaft of the engine fails. A fuse apparatus is provided to link the actuator with the shut-off device in order to transmit the mechanical actuation force. The fuse apparatus disables transmission of the mechanical actuation force when the transmitted mechanical actuation force exceeds a pre-selected level.