Blade Tip Clearance Probe Holder With Spring Rod Assembly
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Solution Overview
Problem
Current methods for measuring blade tip clearance in rotary machines, such as gas turbines, are inadequate due to issues like rod breakage, measurement errors, and the inability of existing probe holders to effectively measure through multiple independently moving features, leading to inefficiencies and potential damage.
Innovation Solution
A blade tip clearance probe holder with a spring rod assembly and electrical capacitance clearance meter that maintains a constant spatial relationship with multiple features of the casing, using a preload mechanism and a ball-and-socket joint to accommodate thermal expansion and radial growth, ensuring accurate gap measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin metal rod is used to measure blade tip clearance, then the measurement method is simple, but the rod often bends or breaks and causes damage to the engine
Solution Approach 1:
The patent replaces the mechanical thin metal rod with an electrical capacitance probe system. The capacitance probe measures blade tip clearance through electrical field interaction without physical contact, eliminating the mechanical rod that bends or breaks. This substitution maintains measurement simplicity while dramatically improving reliability and eliminating damage to the engine.
Solution Approach 2:
The patent introduces an intermediary electrical field between the probe and blade tip for measurement. Instead of direct mechanical contact with a thin rod, the capacitance measurement occurs through an electrical intermediary field, allowing non-contact measurement that avoids the mechanical failures of traditional rods.
2Measurement precision
If custom thin metal rods are made for each measurement, then the measurement can be tailored to specific distances, but the process is difficult and time consuming
Solution Approach 1:
The patent employs a universal capacitance probe holder assembly that can measure various blade tip clearance distances without requiring custom rods for each measurement. The adjustable spring rod mechanism within the holder allows the same device to adapt to different measurement requirements, eliminating the time-consuming process of custom rod fabrication while maintaining measurement precision.
Solution Approach 2:
The patent incorporates an adjustable spring rod assembly that can dynamically adapt to different measurement distances. The spring mechanism allows the probe to adjust its position and maintain optimal measurement geometry for various blade tip clearance conditions, replacing the need for static custom-made rods with a dynamic adjustable system.
3Device complexity
If the probe holder is designed to mount on a single feature, then the structure is simple, but it cannot measure through two or more independently moving features
Solution Approach 1:
The patent divides the probe holder into multiple independent mounting components: a first housing that mounts to a first feature and a second housing that mounts to a second feature. This segmentation allows the probe holder to be configured for multiple independently moving features while maintaining relatively simple individual mounting structures for each feature.
Solution Approach 2:
The patent employs a nested configuration where the second housing is positioned within or adjacent to the first housing, with the capacitance probe extending through both housings to reach the blade tip. This nested arrangement enables measurement through multiple features while keeping the overall structure compact and manageable.
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
The solution provides reliable and accurate measurement of blade tip clearance, reducing air leakage and enabling efficient operation across varying engine conditions, while minimizing the risk of damage and improving measurement precision.
Implementation Method 1
a spring rod assembly in operable communication with the first housing
Implementation Method 2
accommodate thermal expansion and radial growth
Implementation Method 3
an electrical capacitance clearance meter in operable communication with the spring rod assembly
Data Source
AI summary
A blade tip clearance probe holder including: a first housing in operable communication with a first feature of a casing for a rotary machine; a spring rod assembly in operable communication with the first housing; an electrical capacitance clearance meter in operable communication with the spring rod assembly; and a second housing in operable communication with the first housing wherein the second housing initiates a preload on the spring rod assembly and wherein the electrical capacitance clearance meter maintains a constant spatial relationship with a second feature of the casing for the rotary machine.