V-Shaped NMR Magnet System for Homogeneous and Gradient Fields
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Solution Overview
Problem
Existing NMR technologies face challenges in generating a homogeneous magnetic field with regions of strong static magnetic field gradients, which are necessary for characterizing complex mixtures like oils in quality control environments, particularly in low-field settings, and require complex sample preparation and equipment that is not suitable for in-line measurements.
Innovation Solution
A V-shaped magnet system with permanent magnet elements and pole pieces arranged at an angle to create a homogeneous magnetic field in one volume and a gradient field in another, allowing for spectroscopic measurements and in-line analysis without additional sample preparation, using a compact and robust design with adjustable pole pieces and RF coils for different sample sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional yoke-based magnet designs with rectangular frames are used, then a magnetic field can be generated, but the structure is bulky and affected by stray fields extending far beyond the outer contours
Solution Approach 1:
The patent applies asymmetry by transitioning from traditional symmetric rectangular yoke designs to an asymmetric V-shaped magnet arrangement. The V-shape with a defined opening angle creates a more compact structure that inherently contains magnetic flux more effectively, reducing stray field extension beyond the outer contours while maintaining the necessary magnetic field strength for NMR measurements.
Solution Approach 2:
The patent introduces a spatial dimensionality change by arranging magnet elements and pole pieces in a V-shaped configuration rather than a planar rectangular arrangement. This three-dimensional optimization allows the magnetic flux to be contained more efficiently within a smaller volume, reducing the footprint and stray field extent while maintaining measurement capability.
2Volume of moving object
If permanent magnets are used instead of resistive or superconductive coils, then a compact structure is achieved, but flux densities above 2T cannot be generated
Solution Approach 1:
The patent employs composite material principles by combining permanent magnets with soft-magnetic pole pieces made of different materials with complementary properties. The permanent magnets provide the base magnetic field, while the high-permeability soft-magnetic pole pieces concentrate and shape the flux to achieve higher effective field strengths in the measurement region without requiring the permanent magnets themselves to generate fields above 2T.
Solution Approach 2:
The patent applies local quality by designing pole pieces with specific geometric features (such as curved surfaces or varying thickness) that concentrate magnetic flux locally at the air gap where measurements are performed. This allows the magnetic field to be enhanced precisely where needed for NMR measurements while the overall magnet structure remains compact and uses permanent magnets operating below their maximum flux density capability.
3Measurement precision
If a homogeneous magnetic field is generated for NMR measurements, then measurement precision is improved, but device complexity increases due to additional gradient field requirements
Solution Approach 1:
The patent merges the functions of homogeneous field generation and gradient field generation into a single integrated V-shaped magnet system. By strategically positioning permanent magnets and shaping pole pieces, the system simultaneously creates a homogeneous magnetic field region for high-precision NMR spectroscopy and gradient field regions for diffusion and relaxation measurements, eliminating the need for separate gradient coil assemblies and reducing overall device complexity.
Solution Approach 2:
The patent implements multi-functionality by designing the V-shaped magnet arrangement to provide multiple magnetic field configurations (homogeneous and gradient) within a single device structure. This universal design enables the system to perform various NMR measurement types (spectroscopy, diffusion, relaxation) without requiring additional components or complex reconfiguration, thereby improving measurement precision across multiple parameters while controlling device complexity.
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, efficient characterization of liquids by measuring diffusion and relaxation properties in a compact, portable, and robust NMR sensor arrangement, suitable for quality control of oils and other materials, with the ability to perform in-line measurements without complex rearrangements or sample preparation, and is insensitive to temperature drifts.
Implementation Method 1
a magnet system comprising at least two permanent magnet elements (11'; 11'') and pole pieces (12'; 12'') attached to the magnet elements
Implementation Method 2
Nuclear magnetic resonance (NMR) is a commercially widespread method in MR for analyzing and characterizing the chemical composition of substances
Implementation Method 3
a generally V-shaped yoke support structure made of soft magnetic material and configured to resist attracting forces of the magnets and to provide a return path for the magnetic flux
Data Source
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AI summary
An NMR fluid sensor arrangement (1) with a magnet system comprising at least two permanent magnet elements (11'; 11") and pole pieces (12'; 12") attached thereto is characterized in that the magnet elements are disposed at an angle of 20° to 120° to each other providing a V-shaped air gap, are attached to a generally V-shaped yoke support structure made of soft magnetic material and configured to resist attracting forces of the magnets and to provide a return path for the magnetic flux, and that the magnet system is constructed for generating a homogeneous magnetic B0 field in a first volume (V1) and a gradient magnetic field in a second volume (V2) located at a distance from the first volume, both volumes being located inside the V-shaped air gap between the magnet elements. This dedicated, compact NMR-based sensor is suitable for characterization of complex mixtures including oils using a special low field NMR-magnet with regions of homogeneous magnetic field and with regions with strong static magnetic field gradients, where relaxation and diffusion can be measured.