Turbine Wheel Restraint Fixture with Dovetail Interlock
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Solution Overview
Problem
Current methods for restraining a turbine wheel during blade removal or installation are unsafe and prone to hardware damage due to the use of straps, which can break and cause the rotor to roll, posing safety risks and requiring frequent replacement parts.
Innovation Solution
A fixture with a dovetail section that interlocks with the wheel's dovetail slot, featuring a mounting section with coupling rings secured to a stationary anchoring point via a restraint, utilizing a come-along or ratcheting mechanism to prevent wheel rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a strap is used to restrain the rotor, then the restraint method is simple to implement, but the reliability is poor due to strap breakage risk
Solution Approach 1:
The patent introduces a fixture as an intermediary device between the blade and the restraint system. The fixture includes a mounting section that attaches to the blade and a coupling section that connects to the restraint, eliminating the need to directly strap the blade while maintaining restraint functionality and improving reliability through a more secure connection interface
Solution Approach 2:
The patent replaces the simple strap-based mechanical restraint system with a more complex fixture-based system that includes threaded fasteners, coupling rings, and standardized connection interfaces, substituting the inadequate strap mechanism with a robust mechanical assembly designed to prevent breakage
2Device complexity
If a strap is used to restrain the rotor, then the device complexity is low, but the strength is insufficient leading to hardware damage
Solution Approach 1:
The patent divides the restraint system into separate functional components: a mounting section for blade attachment, a coupling section for restraint connection, and the restraint element itself. This segmentation allows each component to be optimized for its specific function while distributing the mechanical loads across multiple elements rather than relying on a single strap
Solution Approach 2:
The fixture is constructed from high-strength materials including steel or titanium for the mounting and coupling sections, combining materials with superior mechanical properties to withstand the high forces involved in rotor restraint while maintaining structural integrity under extreme loading conditions
3Loss of time
If a strap is used to restrain the rotor, then the installation is quick, but the precision of blade positioning is poor causing safety risks
Solution Approach 1:
The fixture is pre-assembled with the mounting section attached to the blade before the restraint operation begins. This preliminary attachment ensures proper positioning and alignment is established in advance, allowing the restraint to be applied immediately without compromising safety while maintaining efficient installation timing
Data Source
AI summary
A fixture for restraining a wheel of a turbomachine has a dovetail section adapted for insertion into a dovetail slot of the wheel. A mounting section is located adjacent to, or formed integrally with, the dovetail section. At least one coupling ring is attached to the mounting section, and the coupling ring is adapted to be secured to a stationary anchoring point via a restraint. The stationary anchoring point includes at least one counterbore assembly having a coupling ring attached thereto. The counterbore assembly is adapted to be secured to a stationary structure. The stationary structure may be a shell, a flange or a casing of the turbomachine.