Downhole Spectrometer Filter Wheel Segmentation and Hypocycloidal Drive
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Solution Overview
Problem
Existing downhole spectrometers have limited measurement capabilities due to spatial constraints on the filter wheel, restricting the number of filters that can be used in the optical path.
Innovation Solution
The implementation of multiple filter wheels in a common plane with omitted segments to allow interference-free rotation and a hypocycloidal filter wheel drive mechanism to increase the number of filters that can intercept the optical path, enabling more filters to be used without reducing light intensity or tool reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single filter wheel is used in the spectrometer, then the device complexity is low and ease of operation is maintained, but the number of filters per optical path is limited due to spatial constraints
Solution Approach 1:
The single filter wheel is divided into multiple separate filter wheels, each containing a subset of filters. This segmentation allows each wheel to be smaller and simpler while collectively providing a larger number of filters. The filters are distributed across multiple wheels rather than crowded into one, resolving the spatial constraint while maintaining operational simplicity through coordinated rotation of the segmented wheels.
Solution Approach 2:
The patent transitions from a single-plane filter wheel to a multi-plane configuration where filter wheels are positioned at different locations along the optical path. By adding the dimensional aspect of multiple planes or positions, the system accommodates more filters without increasing the complexity of individual wheel components, thus resolving the contradiction between quantity and complexity.
2Quantity of substance
If beam splitters or optical switches are used to increase the number of filters, then the measurement capabilities are enhanced, but the tool reliability is reduced in the downhole environment
Solution Approach 1:
The patent extracts and removes the problematic beam splitters and optical switches from the downhole spectrometer system. Instead of using these unreliable components, the invention employs a mechanical filter wheel configuration where filters are physically rotated into the optical path. This extraction of unreliable components directly addresses the reliability concern while maintaining the capability to select multiple filters through the robust mechanical wheel system.
3Quantity of substance
If the filter wheel size is increased to accommodate more filters, then the number of filters increases, but the light intensity is reduced
Solution Approach 1:
By segmenting the filters across multiple smaller wheels rather than one large wheel, each individual filter can be optimally sized to maintain light intensity. The segmentation allows filters to be positioned at optimal locations where they can intercept the optical path effectively without requiring an oversized wheel that would dilute light intensity across a larger area.
Data Source
AI summary
Downhole spectrometer tools are provided with two ways to increase the number of filters on an optical path. A first approach employs multiple filter wheels that rotate alternately in a common plane to intersect the optical path. Portions of the wheels are cut out to avoid mechanical interference between the wheels. A second approach drives the one or more filter wheels with a wobble that causes the filters to trace one or more hypocycloidal curves that each intersect the optical path.