Drive Shaft Disconnector with Meltable Trigger for Catastrophic Failure Isolation
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Solution Overview
Problem
In systems where a driving mechanism, such as a gas turbine engine, is coupled with rotating equipment, there is a need to safely decouple the drive shaft in case of failure to prevent catastrophic damage and reduce maintenance costs.
Innovation Solution
A disconnector system comprising a housing, an arm, a parting tool, a biasing element, and a meltable element that repositions the arm to contact the drive shaft upon failure, causing a controlled failure to decouple the drive mechanism from the rotating equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the drive mechanism is rigidly coupled to the rotating equipment, then power transmission efficiency is improved, but catastrophic damage spreads to other systems upon failure
Solution Approach 1:
The drive shaft is segmented into a first portion (connected to drive mechanism) and a second portion (connected to rotating equipment), with a predetermined failure zone between them. This segmentation allows the shaft to be divided into separable sections that can fail independently at the predetermined zone, preventing catastrophic damage spread while maintaining power transmission efficiency during normal operation.
Solution Approach 2:
The disconnector device acts as an intermediary between the drive mechanism and rotating equipment. It includes a parting tool that can contact the drive shaft at the predetermined failure zone, serving as a mediator that enables controlled separation when failure occurs, thus protecting both the drive mechanism and rotating equipment from catastrophic damage.
2Reliability
If a disconnector device is added to enable controlled decoupling, then protection from catastrophic failure is improved, but device complexity increases
Solution Approach 1:
The disconnector device utilizes the heat generated by the failure itself to trigger the decoupling action. The meltable element melts due to heat from the failed drive mechanism or rotating equipment, automatically releasing the arm to contact the drive shaft. This self-service mechanism eliminates the need for external sensors, controllers, or power sources, thereby reducing device complexity while maintaining high reliability.
Solution Approach 2:
The meltable element undergoes a phase transition from solid to liquid when exposed to heat from a failure. This phase transition automatically triggers the disconnector mechanism, causing the arm to move from the retracted position to the active position where it contacts the drive shaft. The phase transition provides a simple, reliable, and complexity-free way to detect failure and initiate protective decoupling.
3Reliability
If the arm is constantly positioned to contact the drive shaft, then immediate decoupling upon failure is achieved, but the drive shaft is subjected to continuous stress
Solution Approach 1:
The disconnector device is pre-positioned and pre-loaded by the biasing element during normal operation, but the arm remains retracted away from the drive shaft. The preliminary action is prepared (arm positioned, biasing element loaded) without actually contacting the shaft, thus avoiding continuous stress. Upon failure, the pre-positioned arm immediately contacts the drive shaft to achieve rapid decoupling.
Solution Approach 2:
The biasing element applies a preliminary force in the opposite direction to the desired arm movement, keeping the arm retracted during normal operation. This preliminary anti-action prevents the arm from contacting the drive shaft under normal conditions, avoiding unnecessary stress. When the meltable element fails, the preliminary anti-action is removed, allowing the arm to move to the contact position under the stored biasing force.
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
Effectively prevents damage to other systems by ensuring a controlled decoupling of the drive mechanism from the rotating equipment upon failure, reducing maintenance and repair costs by limiting cascading failures.
Implementation Method 1
a meltable element disposed in the housing in a position to restrain the arm in the first position against the bias of the biasing element. When the housing is mounted to at least one of the drive mechanism or rotating equipment, radially spaced from a drive shaft such that the parting tool will contact the drive shaft when the arm is in the second position, a failure in the at least one of the drive mechanism or rotating equipment will cause the meltable element to melt and release the arm for movement to the second position
Data Source
AI summary
A method and disconnector for disconnecting a drive shaft of a drive mechanism from rotating equipment, upon a failure of the drive mechanism or rotating equipment, includes a housing, an arm extending from the housing and movable relative to the housing between a first position and a second position, and a parting tool on a distal end of the arm.