NMR Probe Cryogenic Circuit with Multi-Stream Gas Cooling

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Solution Overview

Problem

Current NMR devices face challenges in maintaining very low temperatures while minimizing energy consumption and reducing the size of heat exchangers, and are inefficient in cooling mechanisms.

Innovation Solution

The NMR analysis device employs a BRAYTON thermodynamic cycle with a turbine that allows isentropic expansion, using multiple gas streams to rotate and cool the sample holder, and includes a cryorefrigerator and heat exchangers to manage temperature effectively, minimizing the size of the heat exchanger and simplifying the device configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal insulation techniques are used to protect components from surrounding thermal radiation and avoid losses by convection or radiation, then temperature stability is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines multiple gas stream functions into a single integrated system. The first gas stream provides cooling, the second creates the aerostatic bearing, and the third drives the turbine for rotation. This merging of functions into one fluid system reduces the need for separate insulation systems and complex thermal management components, thereby reducing device complexity while maintaining temperature stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The third gas stream driving the turbine creates a self-powered rotation system that also contributes to cooling through its expansion. The system uses the cryogenically cooled gas itself to drive the rotation mechanism, eliminating the need for separate motor systems and reducing overall device complexity while maintaining the required rotation function.

Inventive Principle:
Principle #25Self-service

2Use of energy by moving object

If a turbine with isentropic expansion geometry is used to rotate the sample holder, then energy efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidmanufacturing precision
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent optimizes the turbine blade geometry parameters to achieve isentropic expansion. By carefully designing the blade angles, curvature, and spacing, the turbine efficiently converts the thermal energy of the expanding cryogenic gas into rotational mechanical energy. This parameter optimization allows the system to achieve high energy efficiency while maintaining manufacturability through precise but achievable geometric specifications.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If multiple gas streams are used to cool and rotate the sample holder, then cooling capacity is improved, but device complexity increases

Engineering Contradiction:
Improvecooling capacityVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent implements a multi-functional gas distribution system where a single cryogenic fluid source branches into three distinct gas streams, each serving multiple functions. The first stream cools the sample holder, the second creates the aerostatic bearing for frictionless rotation, and the third drives the turbine for rotation. This universal approach using one fluid system for multiple functions reduces device complexity compared to using separate systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the single cryogenic fluid flow into three separate gas streams with distinct functions. This segmentation allows each stream to be optimized for its specific purpose (cooling, bearing, rotation) while still being part of an integrated system. The segmentation enables independent optimization of each function without requiring completely separate systems, thereby improving cooling capacity while managing device complexity.

Inventive Principle:
Principle #1Segmentation

4Volume of stationary object

If the size of the heat exchanger is minimized, then device compactness is improved, but heat transfer efficiency decreases

Engineering Contradiction:
Improveheat exchanger sizeVSAvoidheat transfer efficiency
Core Design Contradiction:
Volume of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality optimization to the heat exchanger design by focusing heat transfer enhancement at critical locations rather than uniformly across the entire heat exchanger. The counter-current flow arrangement concentrates heat transfer activity where temperature gradients are most effective, allowing for a more compact design that maintains adequate heat transfer efficiency through localized optimization rather than requiring a large uniform heat exchanger volume.

Inventive Principle:
Principle #3Local quality

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

This approach enables efficient operation at very low temperatures with reduced energy consumption, improving the cooling capacity and minimizing the size of the heat exchanger, thus enhancing the overall performance of the NMR analysis device.

Implementation Method 1

a turbine (14), in kinematic connection with the rotor (31), having a geometry such that it allows an isentropic expansion of a third fluid M3 which passes through it

Methodology Applied
Scientific EffectIsentropic expansion: Adiabatic Cooling

Implementation Method 2

a first gaseous flow M1 towards the sample holder (12), this flow having the function of cooling the sample holder (12) and/or the sample (15)

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 3

a second gaseous flow M2 towards the bearing (13), the bearing (13) being of the aerostatic or aerodynamic type

Methodology Applied
Scientific EffectAerostatic or aerodynamic bearing: Air Lubrication

Implementation Method 4

a second heat exchanger (19) in which the first and second gaseous flows M1, M2 transfer, respectively upstream of the bearing (13) and the sample holder (12), heat to a fourth M4 or sixth M6 gaseous flow

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP2939043B1Probe, device and method for nuclear magnetic resonance analysis
Publication Date: 2023.02.01 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2939043B1 patent drawingFigure 1
  • EP2939043B1 patent drawingFigure 2A
  • EP2939043B1 patent drawingFigure 2B

AI summary

The invention relates to an NMR analysis device and an operating method for an NMR analysis device (7) comprising a circuit including an NMR analysis probe (9) and a cryostat (8) which are connected by a cryogenic line (16), characterised in that the method comprises a step for the configuration of the aforementioned circuit through which fluids (MO to M9) flow, said configuration step comprising the use of different operating modes for the device (7) according to the activation/deactivation of redirection elements (VC1, VC2, VC3, VC4) and/or the closed/open mode configuration of looping elements (A1 to A11) of the circuit.