NMR Sample Holding Device Against Temperature-Gas Lift
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Solution Overview
Problem
The challenge in NMR benchtop spectrometers with permanent magnets is the limited space for automation, leading to dynamic pressure issues due to temperature control gas, which causes NMR samples to be lifted from their measuring position, affecting resonance frequency and magnetic field stability.
Innovation Solution
A movable holding device is installed in the NMR spectrometer to secure the NMR sample in place using a force-fitting or positive fit, ensuring Ff > Fdynamic - Fweight, where Fdynamic is the buoyancy force and Fweight is the sample weight, allowing for precise temperature control without displacing the sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If temperature control gas is passed through the annular air gap to control sample temperature, then temperature control of the NMR sample is achieved, but dynamic pressure lifts the sample from its measuring position
Solution Approach 1:
The holding device applies a downward force to counterbalance the upward dynamic pressure force generated by the temperature control gas flow. This counteracting force prevents the sample tube from being lifted, maintaining its position stability while temperature control continues to function effectively.
Solution Approach 2:
The holding device acts as an intermediary mechanical element between the sample tube and the temperature control gas flow. It provides a physical constraint that mediates the conflict between gas flow (for temperature control) and sample position stability, allowing both functions to coexist without interference.
2Measurement precision
If a holding device is added to secure the sample tube, then sample position stability is improved, but device complexity increases
Solution Approach 1:
The holding device is designed as a separate, extractable component that can be independently added to the NMR spectrometer system. This modular approach allows the holding function to be taken out as a distinct element, simplifying the overall system architecture and making it easier to implement without redesigning the entire device.
Solution Approach 2:
The holding device is designed to work universally with standard NMR sample tubes and can be integrated into various NMR spectrometer configurations. Its multi-functional design allows it to serve both as a positioning device and as a component that works in conjunction with the existing temperature control system, reducing the need for additional specialized components.
3Temperature
If the air gap between temperature control pipe and sample tube is reduced, then temperature control efficiency is improved, but space for automation and supply lines is reduced
Solution Approach 1:
The solution addresses the spatial conflict by utilizing the vertical dimension for the holding device's clamping action, while the radial dimension maintains the necessary air gap for both temperature control and automation access. This dimensional separation allows temperature control efficiency to be improved through optimized gap geometry without compromising the horizontal space needed for automated sample handling and supply line routing.
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 solution ensures secure spatial fixation of the NMR sample during measurement, enabling optimal temperature control and maintaining magnetic field stability, allowing for automated operation and improved measurement reproducibility.
Implementation Method 1
a force or static friction Ff acting axially on the sample tube
Implementation Method 2
dynamic pressure issues due to temperature control gas, which causes NMR samples to be lifted from their measuring position
Implementation Method 3
temperature control gas for temperature control of the NMR measurement sample in the sample tube can be passed from a temperature control system through a gas inlet
Implementation Method 4
a permanent magnet device for generating a B0 field in a measurement volume
Data Source
AI summary
An NMR spectrometer (10) with a permanent magnet device (11) with measurement volume (12) and bore (13) for inserting an NMR measurement sample contained in a sample tube (14), and with an RF coil (15) outside a cylindrical temperature control pipe (16) with a continuous annular air gap (17) through which temperature control gas can be conducted through a gas inlet (18), is characterized in that on the end opposite the gas inlet, a movable holding device (19) is installed which, in a first operating position, does not touch the sample tube, in a second operating position, holds the sample tube in its measuring position at its outer circumference in a force-fitting and/or form-fitting manner with an axially acting force or static friction Ff, and, in a third operating position, releases the sample tube for removal, and that in the second operating position Ff>Fdynamic−Fweight, where Fdynamic is the buoyancy force generated by the dynamic pressure of the temperature control gas flowing onto the sample tube and Fweight is the weight force of the sample tube. This enables the problems of known arrangements of the type in question with the dynamic pressure caused by the temperature control gas to be avoided.