Triggered White Light Interferometry for Rotating Radial Clearance
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Solution Overview
Problem
Conventional measurement systems for clearance gaps between rotating and nonrotating components, particularly in nonmetallic structures, are inadequate as they rely on electric or magnetic field variations, which are ineffective for nonmetallic components.
Innovation Solution
Employing white light interferometry with a high-speed camera and beam splitter to measure clearance between rotating and fixed structures by projecting a white light beam and capturing interference patterns to determine radial growth and clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional measurement instrumentations using electric or magnetic field variations are employed, then measurement capability is provided for metallic components, but measurement is impossible for nonmetallic components
Solution Approach 1:
The patent replaces electric and magnetic field-based measurement systems with an optical measurement system using white light interferometry. This substitution enables measurement of nonmetallic components by using light reflection and interference patterns instead of electromagnetic field interactions, which do not work with nonconductive materials.
Solution Approach 2:
The patent changes the measurement parameter from electromagnetic field variations to optical path length differences. By using white light interferometry, the system measures clearance gaps through changes in optical path length as light reflects off the rotating component surface, a parameter that works independently of material conductivity.
2Measurement precision
If white light interferometer circuitry continuously measures clearance, then accurate clearance data is obtained, but system complexity and energy consumption increase
Solution Approach 1:
The patent uses periodic actuation of the white light interferometer synchronized with the rotation period of the component. The position detector triggers the interferometer to measure clearance only when specific portions of the rotating structure pass predetermined positions, converting continuous measurement into periodic discrete measurements that reduce system complexity while maintaining accuracy.
Solution Approach 2:
The patent implements preliminary detection of rotational position using a position detector before activating the white light interferometer. This preliminary action triggers the main measurement system only when needed, avoiding continuous operation and reducing overall system complexity while ensuring measurements are taken at the correct moments.
3Loss of information
If clearance measurement is performed during rotation, then operational clearance data is obtained, but measurement difficulty increases for nonmetallic rotating components
Solution Approach 1:
The patent introduces an intermediary optical system (white light interferometer with beam splitter and reference mirror) that mediates between the rotating nonmetallic component and the measurement device. This intermediary system captures optical reflections from the rotating surface and converts them into measurable interference patterns, making it possible to measure clearance on nonmetallic rotating components without direct contact.
Solution Approach 2:
The patent replaces mechanical contact-based measurement methods with optical non-contact measurement. By using white light interferometry, the system can measure clearance on rotating nonmetallic components without physical contact, eliminating the difficulties associated with mounting sensors on rotating parts and avoiding interference with the rotation itself.
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
Enables accurate measurement of clearance gaps in nonmetallic components experiencing rotating stresses, preventing damage by detecting radial growth and maintaining operational safety.
Implementation Method 1
A white light interferometer circuitry reflects a white light beam off of at least one portion of the rotating structure responsive to the actuation signal to determine a clearance between the at least one portion of the rotating structure and an inner surface of the fixed structure
Implementation Method 2
A laser projects a laser beam toward the rotating structure in a fixed position. A detector detects a reflection of the laser beam from the reflector when the reflector reflects the laser beam responsive to rotation of the reflector past the fixed position of the laser beam
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus measures clearances between a rotating structure (102) within a fixed surrounding structure (106). A position detector (234) determines when at least one portion of the rotating structure (102) rotates past a hole (216) defined in the fixed surrounding structure (106) and generates an actuation signal responsive to rotation of the at least one portion of the rotating structure (102) past the hole (216) defined in the fixed surrounding structure (106). White light interferometer circuitry reflects a white light beam (208) off of at least one portion of the rotating structure (102) responsive to the actuation signal to determine a clearance between the at least one portion of the rotating structure (102) and an inner surface (112) of the fixed structure (106). The actuation signal actuates the white light interferometer circuitry to reflect the white light beam (208) off of the at least one portion of the rotating structure (102) through the hole (216) defined in the fixed surrounding structure (102).