Ellipsoidal-Mirror Optical Arrangement for Two-Chamber DRIFT Interchange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing measuring cells for DRIFT spectroscopy are not suitable for iso-potential spectroscopy due to issues such as sample condensation, large dead volume, undesired bypass flows, and difficulty in obtaining quantitative results under varying conditions, which hinder the application of the Kubelka-Munk equation for accurate spectral analysis.
Innovation Solution
An optical assembly for a measuring cell with two sample crucibles or chambers, featuring a base plate assembly, optical unit, and a rotary stroke actuator, which allows for precise positioning of samples within the beam path, minimizes heat transfer, and maintains consistent chemical potential, enabling reproducible DRIFT spectroscopy measurements under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sample crucible is used in conventional measuring cells, then the device complexity is reduced, but the measurement precision and reliability are insufficient for quantitative DRIFT spectroscopy under varying conditions
Solution Approach 1:
The measuring cell is divided into multiple independent sample crucibles (at least two) that can be independently positioned in the optical beam path. This segmentation allows separate measurement of samples under identical conditions, enabling quantitative analysis through comparison while maintaining a relatively simple overall cell structure.
Solution Approach 2:
Multiple sample crucibles are prepared in advance with different samples or reference materials, and the system is designed to rapidly interchange them in the beam path. This preliminary preparation eliminates the need for repeated sample loading during measurement, ensuring consistent conditions for quantitative comparison.
2Reliability
If the measuring cell is heated to high temperatures for catalyst studies, then the reliability of reaction condition simulation is improved, but sample condensation occurs on spectral windows
Solution Approach 1:
The measuring cell employs differentiated thermal zones: the sample crucible region is heated to high temperatures for reliable catalyst reaction simulation, while the spectral window regions are maintained at lower temperatures or equipped with heating elements to prevent condensation. This local quality differentiation resolves the contradiction between high-temperature reliability and condensation prevention.
Solution Approach 2:
Heating elements positioned near the spectral windows act as intermediary components that prevent condensation by creating a thermal gradient. These intermediaries protect the optical windows from direct exposure to cold sample vapor while allowing the main sample zone to maintain high reaction temperatures.
3Measurement precision
If the optical assembly is designed for high-precision sample positioning, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The optical assembly incorporates movable components such as motorized positioning stages or rotatable sample holders that enable dynamic interchange of sample crucibles in the beam path. This dynamic capability allows precise positioning of multiple samples without requiring complex fixed mechanical structures, balancing measurement precision with manageable device complexity.
4Adaptability or versatility
If the measuring cell volume is increased to accommodate multiple sample crucibles, then the adaptability for comprehensive analysis is improved, but the dead volume increases causing undesired bypass flows
Solution Approach 1:
The measuring cell divides the gas flow path into separate, isolated channels for each sample crucible. This segmentation allows multiple samples to be measured under identical flow conditions without creating bypass flows between samples, maintaining low dead volume while accommodating comprehensive analysis requirements.
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 assembly enables fast, reproducible, and accurate DRIFT spectroscopy measurements at high temperatures and pressures, allowing for the application of the Kubelka-Munk equation, thereby improving the quantification of IR spectra and facilitating comprehensive analysis of catalyst surfaces.
Implementation Method 1
diffusely scattered infrared light can be collected thereby in the largest possible solid angle range and can be bundled onto a detector
Implementation Method 2
an optical unit or optical assembly, with which incident infrared light can be bundled onto a sample located in its focus
Implementation Method 3
The mirrors may be mounted with mirror mounts on kinematic mounts. The mirror mounts may be cooled via a cooling plate connected to the mirror mounts or the kinetic mounts.
Implementation Method 4
The cooling plate contains a cooling channel and two ports
Implementation Method 5
each spectroscopy chamber comprises a casing comprising a gas port, a first port for an electrical connection, a second port for an electrical connection, a crucible, a heating element
Implementation Method 6
the chamber plate is connected to the base plate assembly via a rotary stroke actuator, wherein the rotary stroke actuator is configured to move the chambers vertically and rotate the chambers horizontally into the beam path
Implementation Method 7
measuring at one or more temperatures, T, an intensity of infrared radiation diffusely reflected by a catalyst-containing material
Implementation Method 8
DRIFTS method (diffuse reflection infrared Fourier transform spectroscopy)
Data Source
Figure 1
Figure 2a)~2c)
Figure 3a)~3e)
AI summary
An assembly for studying a sample comprising: a base plate assembly (100), an optical unit (200) comprising a cooling plate (203), an entrance and exit flat mirror (903, 904), an entrance ellipsoidal mirror (901), an exit ellipsoidal mirror (902), and a focussing lens (905) configured to bundle the rays received from the exit flat mirror (904), wherein ellipsoidal mirror mounts (206, 207) are connected to the cooling plate (203), the assembly further comprising a chamber plate (300) having two spectroscopy chambers (400), wherein the chamber plate (300) is connected to the base plate assembly (100) via a rotary stroke actuator (500), wherein the rotary stroke actuator (500) is configured to move the chambers (400) horizontally and rotate the chambers (400) vertically into the beam path under the optical unit (200), wherein the chamber plate (300) comprises a cooling channel (305) and two ports (302), wherein the first port is connected to an inlet of the cooling channel (305) and the second port is connected to an outlet of the cooling channel (305).