Propeller Feathering via Frangible Retainer Tabs and Beta Tube
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Solution Overview
Problem
Existing propeller feathering systems during or following an undesired shutdown of turbines are often complex and prone to failure, necessitating a simpler and more reliable failsafe method to reduce drag and maintain safety.
Innovation Solution
A feathering system comprising a sleeve and retainer with frangible tabs that decouple under critical torque, allowing axial movement of a beta tube assembly to automatically feather propeller blades, reducing the complexity and redundancy of existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex or redundant systems are used for feathering during undesired shutdown, then reliability may be improved, but device complexity increases and risk of system failure increases
Solution Approach 1:
The patent extracts the essential feathering function from complex redundant systems by using a simple beta tube assembly that directly converts hydraulic pressure into mechanical motion. The beta tube expands axially under pressure to rotate the propeller blades, eliminating the need for complex linkages, multiple valves, and redundant components while maintaining reliability through the inherent simplicity and directness of the mechanism.
Solution Approach 2:
The feathering system operates autonomously during undesired shutdown conditions. The beta tube assembly automatically expands when hydraulic fluid is introduced, directly driving the propeller blades to the feathered position without requiring external control systems, sensors, or complex actuation mechanisms. This self-service operation eliminates points of failure associated with complex control systems.
2Ease of operation
If traditional feathering systems are used, then propeller feathering can be achieved, but the number of components increases and system simplicity decreases
Solution Approach 1:
The patent merges multiple functions into the single beta tube assembly. The beta tube simultaneously serves as the hydraulic actuator, the mechanical linkage, and the direct driver of propeller rotation. By combining these previously separate components into one integrated element, the system achieves feathering operation with minimal components, enhancing simplicity and ease of operation.
Solution Approach 2:
The system uses hydraulic fluid introduced into the beta tube to generate the expanding force needed for feathering. This hydraulic approach replaces complex mechanical linkages and multiple actuators with a single fluid-powered expansion mechanism, reducing component count while maintaining operational simplicity and reliability.
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 simplifies the feathering process, reduces the number of components, and enhances propeller assembly and turbine safety by enabling automatic feathering during overtorque conditions, thereby preventing damage and ensuring operational safety.
Implementation Method 1
at least the retainer tabs of the retainer are defined by a frangible material configured to detach from the retainer at a force corresponding to a critical torque value applied by the beta tube assembly onto the sleeve
Implementation Method 2
a beta tube assembly extended through the sleeve along the axial direction, wherein the beta tube assembly defines one or more internal walls, wherein the one or more internal walls defines a hydraulic fluid transfer cavity in fluid communication with one or more hydraulic fluid transfer orifices
Data Source
AI summary
A system for feathering a propeller assembly disposed within a housing of the propeller assembly has a sleeve defining an outer wall and one or more sleeve tabs extended outward in a radial direction along at least a circumferential portion of the sleeve, wherein the one or more sleeve tabs is separated from the outer wall in an axial direction, a retainer defining one or more retainer tabs extended inward in the radial direction, wherein the one or more retainer tabs is disposed between the outer wall and the one or more sleeve tabs of the sleeve along the axial direction, and a beta tube assembly extended through the sleeve along the axial direction. The beta tube assembly defines one or more internal walls. The one or more internal walls defines a hydraulic fluid transfer cavity in fluid communication with one or more hydraulic fluid transfer orifices.