Capillary Sample Presentation Device for X-ray Diffraction
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Solution Overview
Problem
Current radiation-based analytical equipment, such as X-ray diffraction chambers, face limitations in rapidly changing gas compositions, temperature, and pressure ranges, particularly due to bulky designs and the inability to handle liquids or corrosive gases, which restricts the determination of kinetic information and real-life application conditions.
Innovation Solution
A sample presentation device featuring a capillary reaction chamber made of thermally conductive materials with adjustable positioning, infrared heating, and compression fittings for secure capillary placement, allowing operation up to 500°C and 10 bars, and accommodating liquids and vapors, with a thermocouple for precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large volume reaction chamber with plate-like sample holder is used, then the sample can be accommodated, but the gas changeover time increases and dead volumes are created
Solution Approach 1:
The reaction chamber is segmented into a capillary tube format, dividing the sample into a long narrow channel rather than a bulk volume. This segmentation reduces dead volumes and allows rapid gas changeover while maintaining sufficient sample quantity for analysis.
Solution Approach 2:
The sample presentation transitions from a two-dimensional plate-like holder to a three-dimensional capillary tube structure. This dimensional change enables rapid gas flow through the sample while maintaining sample integrity, eliminating dead volumes associated with plate geometries.
2Reliability
If beryllium or similar X-ray invisible windows are used, then the chamber can be sealed, but the temperature and pressure ranges are limited
Solution Approach 1:
The window material is changed from beryllium to quartz glass, which allows the operating parameters (temperature and pressure) to be extended to higher ranges while maintaining X-ray transparency and chamber sealing integrity.
Solution Approach 2:
The capillary tube is made of quartz glass, a composite material that combines X-ray transparency with high temperature and pressure resistance, eliminating the limitations imposed by beryllium windows.
3Loss of time
If a capillary tube is used for the reaction chamber, then rapid gas changeover is enabled, but the sample presentation to radiation may be suboptimal
Solution Approach 1:
The capillary tube is made rotatable about its own axis, allowing dynamic adjustment of the sample orientation relative to the radiation source. This enables optimal sample presentation for X-ray diffraction while maintaining the rapid gas changeover capability inherent in the capillary design.
Solution Approach 2:
The periodic rotation of the capillary tube allows the sample to be presented in different orientations during the X-ray measurement cycle, improving measurement precision while the rapid rotation capability maintains fast gas changeover during catalytic studies.
4Stability of the object's composition
If a bulky reactor chamber design is used, then the sample holder can be stable, but dead volumes are created and plug flow pattern is compromised
Solution Approach 1:
The sample is segmented into a capillary tube format, creating a long narrow channel that eliminates dead volumes and establishes a true plug flow pattern. This segmentation maintains sample stability while improving kinetic data accuracy by removing volume-related artifacts.
Solution Approach 2:
The mechanical stability provided by bulky plate holders is replaced by the inherent structural stability of the capillary tube geometry itself. The capillary's narrow dimensions and length provide sufficient mechanical support and flow control without requiring large volume chambers.
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 rapid gas changes, precise temperature control, and efficient handling of liquids and vapors, facilitating accurate kinetic data collection and reducing turn-over time in materials screening, while minimizing dead volumes and radiation losses, thus providing a cost-effective and practical solution for laboratory X-ray diffraction and synchrotron applications.
Implementation Method 1
a radiant infrared heater (12) that is radially offset from an installed capillary tube (7) for heating it
Implementation Method 2
a thermocouple (23) associated with the mounting base (1) for measuring the temperature of the capillary tube (7)
Implementation Method 3
the connector (11) being of a compression seal type
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A sample presentation device for radiation-based analytical equipment comprises a mounting base (1), a carrier (3) carried by and adjustable in position relative to the mounting base (1), and an arm (9) extending from the carrier (3) and having at its opposite end a terminal member (10). The carrier (3) and terminal member (10) each have coaxial connectors (11) for receiving two opposite end regions of a capillary tube (7) that forms, in use, a reaction cell. A radiant heater (12) is radially offset from the axis of the coaxial connectors (11) for heating, in use, a capillary tube (7) mounted by way of the coaxial connectors. The carrier (3) and terminal member (10) each have a flow path (15) passing therethrough and communicating with the central bore of the coaxial connectors (11), the flow paths (15) having associated with them heating means (18,19) whereby the flow paths can be heated, in use.