Optical Measuring Cell with Cylindrical Geometry for Robust Spectroscopy
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Solution Overview
Problem
Conventional multipass optical measuring cells are fragile and sensitive to thermal changes and mechanical shocks, making them unsuitable for robust and precise absorption spectroscopic analysis of chemical and physical parameters in fluids.
Innovation Solution
An optical measuring cell with a housing containing a tube, cover, and base, where a light beam is coupled in parallel to the optical main axis and deflected by roof prisms, plano-convex lenses, or concave mirrors, allowing multiple passes through the fluid for precise and robust analysis, with a design that includes a gas-tight housing and robust deflecting elements to minimize interference and ensure reliable measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multipass cells (White cell, Herriott cell) are used to increase optical path length, then detection sensitivity is improved, but the cells become fragile and sensitive to thermal changes and mechanical shocks
Solution Approach 1:
The patent replaces traditional mechanical mirror-based multipass cell designs with a cylindrical measuring cell that uses the cylindrical geometry itself to guide and reflect the light beam multiple times. This substitution of mechanical components with a geometric structure eliminates the fragility associated with mirrors while maintaining the extended optical path length for improved detection sensitivity.
Solution Approach 2:
The patent changes the geometric parameters of the measuring cell by采用 a cylindrical shape with specific radius and length dimensions. This geometric parameter change enables the light beam to undergo multiple reflections along the cylindrical path, extending the optical path length without requiring fragile mechanical components, thus improving both sensitivity and robustness.
2Measurement precision
If the optical path length is extended through multiple passes, then detection sensitivity is improved, but the device complexity increases
Solution Approach 1:
The patent segments the optical path into multiple discrete reflection segments within the cylindrical geometry. The light beam traverses the cylinder length multiple times with each pass, creating segmented optical paths that extend the total path length without requiring complex external optical components, thus improving sensitivity while keeping the device simple.
Solution Approach 2:
The cylindrical measuring cell serves multiple functions simultaneously: it contains the sample fluid, guides the light beam through multiple passes, and provides the reflective surfaces for the optical path. This multi-functionality eliminates the need for separate optical components, reducing device complexity while achieving extended optical path length for improved detection sensitivity.
3Measurement precision
If traditional multipass cell designs are used, then absorption spectroscopic analysis can be performed, but the cells are not robust enough for precise measurements
Solution Approach 1:
The patent replaces fragile mechanical mirror assemblies with a robust cylindrical structure that inherently guides and reflects light. This substitution maintains the precision required for absorption spectroscopy while providing the mechanical robustness needed for reliable measurements, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent employs a composite design combining the cylindrical geometry with appropriate materials for the housing and optical elements. This composite approach creates a measurement cell that is both optically precise for accurate spectroscopic analysis and mechanically robust for reliable operation, simultaneously achieving high measurement precision and reliability.
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 design enables precise and robust determination of chemical and physical parameters, such as gas concentration and dew point, with improved tolerance to external influences and reduced sensitivity to light coherence, focusing on a defined light path for accurate absorption spectroscopy.
Implementation Method 1
the optical path length is deflected by optical reflecting elements in such a way that the measuring cell is passed through multiple times
Implementation Method 2
two prisms are arranged symmetrically in the measuring chamber in such a way that they are slightly offset from each other, and the laser beam enters the measuring cell and exits the measuring cell after it has made multiple passes through the total reflection of the prisms
Implementation Method 3
A light beam for the absorption spectroscopic analysis is coupled into the interior of the housing, together with the fluid to be analyzed, via a coupling-in element connected to the housing, in such a way that the coupled-in light beam runs in the interior of the housing in parallel to the optical main axis
Implementation Method 4
the output of the cell is the input of an optical detector, which detects specific changes in the properties of the beam due to the pass through the measuring cell, so that the desired statements on the components to be analyzed may be derived therefrom
Implementation Method 5
Optical measuring cells of this type are frequently used in spectroscopy to observe components of low concentration
Data Source
AI summary
An optical measuring cell designed and provided for the absorption spectroscopic determination of at least one chemical and/or physical parameter of a fluid. A light beam for the absorption spectroscopic analysis is coupled into an interior of a housing, together with the fluid to be analyzed, via a coupling-in element connected to the housing such that the coupled-in light beam runs in the interior of the housing in parallel to the optical main axis of the measuring cell or the housing. A coupling-out element connected to the housing couples a light beam striking the coupling-out element out of the housing in order to supply the light beam, after multiple passes through the interior, to a detector for the absorption spectroscopic determination of a chemical and/or physical parameter of the irradiated fluid.