Shaft Deformation Measurement Using Curved Optical Patterns
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Solution Overview
Problem
Existing methods for measuring shaft deformation in gas turbines, steam turbines, or electric generators are often inaccurate due to the small nature of the deformation, leading to unreliable measurements.
Innovation Solution
A device with a curved pattern on the shaft, a radiation source, and a movable carrier with a sensor is used to detect radiation reflections before and after deformation, determining shaft deformation by calculating the distance between reference positions, allowing for precise measurement of circumferential deformation and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement of shaft deformation is used, then the measurement system is simple, but the measurement precision is insufficient due to small deformation values
Solution Approach 1:
The patent transforms the measurement from direct angular deformation detection to optical path displacement detection. By projecting a curved pattern onto the shaft surface and measuring the displacement of reflected light patterns in a different dimension (optical space), the system amplifies small deformation angles into measurable linear displacements, thereby improving measurement precision without excessively complicating the device
Solution Approach 2:
The patent introduces an intermediary curved pattern as a mediator between the shaft and the measurement system. This pattern acts as an optical interface that converts mechanical deformation into optical signal changes. The radiation source and sensor detect changes in the reflected light pattern, which indirectly measures the shaft deformation with higher precision than direct measurement methods
2Measurement precision
If a curved pattern with radiation source and sensor is used, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The carrier serves multiple functions: it holds both the radiation source and the sensor, provides movable positioning along the shaft axis, and supports the optical components. This multi-functionality reduces the number of separate components needed, thereby managing device complexity while maintaining improved measurement precision through the curved pattern method
Solution Approach 2:
The carrier is designed to be movable along the shaft axis, allowing dynamic positioning of the radiation source and sensor to optimize measurement conditions. This dynamic capability enables the system to adapt to different measurement scenarios and maintain precision while using a relatively simple movable platform rather than multiple fixed measurement stations
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 method provides accurate and reliable measurement of shaft deformation, amplifying small changes for easier detection and compensating for axial shifting, resulting in improved measurement precision.
Implementation Method 1
a radiation source for illuminating the pattern; a sensor for detecting the radiation reflected by the pattern
Data Source
AI summary
A method for measuring deformation of a shaft by a device includes illuminating a pattern applied on the shaft before the deformation is applied; and detecting a first reference position by detecting the radiation reflected by the pattern, after the deformation is applied illuminating the pattern and detecting a second reference position by detecting the radiation reflected by the pattern. Based on the distance between the first and the second reference positions, the shaft circumferential deformation and/or torque is determined.