Multi-Chamber DRIFT Measuring Cell for Window Condensation Control
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Solution Overview
Problem
Existing measuring cells for DRIFT spectroscopy are not suitable for isopotential studies of heterogeneously catalyzed reactions due to issues such as condensation of substances at spectral windows, large dead volumes, unwanted bypass flows, and inability to perform quantitative analysis under identical conditions, limiting the evaluation of spectra and kinetic studies.
Innovation Solution
A measuring cell designed for DRIFT spectroscopy with features like a housing made of anodized aluminum, purge gas connections, a locking mechanism, and three spectroscopy chambers, allowing for precise alignment and temperature control, and gas-tight seals to maintain identical conditions, enabling simultaneous measurement of multiple samples under identical process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a measuring cell is designed for DRIFT spectroscopy with spectral windows, then electromagnetic radiation can pass through, but substances condense at the spectral windows causing interference
Solution Approach 1:
The patent introduces a gas-tight seal system with O-rings and sealing surfaces that act as intermediaries between the sample chamber and the spectral windows. This seal system prevents direct contact between reactants and the windows while maintaining gas-tight isolation, thereby preventing condensation on the windows and ensuring reliable spectroscopic measurements.
Solution Approach 2:
The measuring cell is designed with a controlled inert environment inside the sample chamber, isolated from the external atmosphere by gas-tight seals. This inert environment prevents unwanted reactions and condensation on the spectral windows, allowing reliable DRIFT spectroscopy to be performed without interference from moisture or reactive gases.
2Quantity of substance
If the measuring cell has large dead volumes, then it can accommodate more sample, but unwanted bypass flows occur interfering with the reaction conditions
Solution Approach 1:
The measuring cell is segmented into multiple functional zones with defined gas flow paths. The sample chamber is divided into regions with controlled flow, and the gas-tight seal system creates isolated zones that prevent bypass flows. This segmentation allows precise control of reactant flow through the catalyst bed while maintaining accurate reaction conditions.
Solution Approach 2:
The measuring cell incorporates temperature control systems and pressure monitoring that provide feedback to maintain optimal reaction conditions. By monitoring temperature and pressure changes, the system can adjust flow rates and heating parameters to prevent bypass flows and ensure uniform reaction conditions throughout the catalyst bed.
3Productivity
If multiple samples are measured simultaneously, then productivity increases, but maintaining identical conditions becomes difficult
Solution Approach 1:
The measuring cell is designed as a multi-functional system that can simultaneously measure multiple samples while maintaining identical conditions. The gas-tight seal system and controlled environment allow multiple sample chambers to operate in parallel with uniform temperature, pressure, and gas flow conditions, enabling both high productivity and precise measurements.
Solution Approach 2:
The measuring cell employs independent temperature and pressure control systems for each sample chamber, allowing precise adjustment of reaction parameters. By controlling temperature, pressure, and gas flow rates independently in each chamber, the system maintains identical conditions across multiple samples while measuring them simultaneously, thus achieving both high throughput and measurement precision.
4Strength
If the measuring cell is made with steel reactor material, then structural strength is improved, but electromagnetic radiation cannot pass through
Solution Approach 1:
The measuring cell uses different materials for different parts based on local requirements. The structural components are made of strong steel or metal alloys, while the spectral windows and gas-tight seal surfaces are made of radiation-transparent materials such as quartz or specialized polymers. This local differentiation allows the cell to achieve both structural strength and radiation transmission capability.
Solution Approach 2:
The measuring cell employs composite material construction combining metal structural components with radiation-transparent materials. The housing uses strong metal alloys for structural integrity, while the spectral windows and sealing surfaces use quartz, glass, or specialized polymers that are transparent to infrared radiation. This composite approach resolves the contradiction between strength and radiation transmission.
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 reliable determination of gas-phase and surface species spectra without significant background contributions, allowing for quantitative analysis and understanding of heterogeneously catalyzed reactions by ensuring identical conditions and minimizing interference.
Implementation Method 1
a measuring cell for examining samples using electromagnetic radiation, in particular for isopotential spectroscopy, and more preferably for DRIFT spectroscopy
Implementation Method 2
The so-called DRIFTS method (Diffuse Reflection Infrared Fourier Transform Spectroscopy)
Implementation Method 3
a heating cartridge (26) located in the base, thus enabling temperature measurement and control directly within the sample material
Implementation Method 4
a thermocouple (25) can be inserted into the sample material
Implementation Method 5
The use of O-rings (18b, c) creates gas-tight seals between the interior of the spectroscopy chamber and the exterior, or between the individual components
Implementation Method 6
Since the heterogeneously catalyzed reactions take place or are catalyzed on the catalyst surface
Data Source
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AI summary
The invention relates to a measuring cell (100) for examining samples using electromagnetic radiation, preferably with DRIFT spectroscopy, which has beam entry and exit windows (30), an optical mirror system (5a-c) and a sample plate (8), characterized in that the measuring cell (100) comprises purge gas connections (1a-c), a mirror system for recording DRIFT spectra (5a-c), a sample plate (8) with at least 3 spectroscopy chambers (10) mounted on the sample plate, which is connected via a receptacle (39) to a rotary and lifting motor (9), whereby the chambers (10) can be moved horizontally and rotated into the beam path and aligned under the mirror optics (5a-c), and wherein each of the chambers (10) has a base (11), a sample crucible (12) and a lid (13), wherein these 3 components are connected to each other gas-tight by means (14, 15, 19) and are closed off from the surroundingsThe sample crucible (12) is provided with a bore (20) through which reaction gas from an external reactor connected to the measuring cell is passed through the sample material and out of the chamber (10), and each chamber (10) has a lid (13) with two cones (28) into which windows (30) transparent to electromagnetic radiation, in particular IR radiation, are inserted and arranged so that radiation entering and leaving the measuring cell can pass through these windows (30), the lid (13) having a channel (34) with a gas connection (35a) for introducing reaction gases from an external reactor (42) into the chamber (10), and the chamber (10) having a reaction gas outlet (43) in the base (11) of the chamber (10).