NMR Probe Cryogenic Cooling via Brayton Cycle Turbine

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Solution Overview

Problem

Current NMR devices face challenges in maintaining very low temperatures efficiently while minimizing heat energy consumption and reducing the size of the heat exchanger, as existing thermal insulation techniques are insufficient.

Innovation Solution

The NMR analysis device incorporates a probe with a turbine for isentropic expansion of a fluid, a cryorefrigerator, and counter-current heat exchangers to implement a BRAYTON thermodynamic cycle, optimizing fluid flow and heat exchange to achieve low temperatures with reduced energy consumption and smaller heat exchanger size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal insulation techniques are used to maintain very low temperatures, then temperature stability is improved, but energy consumption increases and heat exchanger size must be large

Engineering Contradiction:
Improvetemperature stabilityVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent changes the thermodynamic parameters of the system by implementing a closed-loop cryogenic circuit with a Brayton cycle, using gas compression and expansion to actively control temperature rather than relying solely on passive insulation. This allows maintaining very low temperatures with reduced energy consumption and smaller heat exchangers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite approach combining thermal insulation techniques with an active cryogenic cooling system featuring counter-current heat exchangers and a Brayton cycle. This hybrid system achieves superior temperature stability while minimizing energy consumption and heat exchanger size compared to insulation alone.

Inventive Principle:
Principle #40Composite materials

2Temperature

If thermal insulation techniques are used to maintain very low temperatures, then temperature stability is improved, but heat exchanger size increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidheat exchanger size
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The patent transforms the temperature control approach from passive insulation to active thermodynamic cycling, using gas compression and expansion processes. This enables achieving the same temperature stability with a significantly reduced heat exchanger volume by utilizing the refrigeration effect of expanding gas.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines thermal insulation with a compact active cooling system using counter-current heat exchangers and a Brayton cycle. This composite approach achieves superior temperature stability while minimizing heat exchanger size through efficient heat transfer and refrigeration effects.

Inventive Principle:
Principle #40Composite materials

3Temperature

If conventional cooling systems are used, then temperature control is achieved, but device complexity increases

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

Solution Approach 1:

The patent implements a multi-functional closed-loop system where the same cryogenic circuit serves multiple purposes: cooling the NMR probe, driving the rotor via turbine expansion, and providing thermal shielding. This integration reduces overall device complexity compared to separate conventional cooling, rotation, and insulation systems.

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

Solution Approach 2:

The patent creates a composite system integrating thermal management, rotation drive, and thermal shielding functions into a unified cryogenic circuit using a Brayton cycle. This multi-functional approach simplifies the overall device architecture compared to conventional separate systems.

Inventive Principle:
Principle #40Composite materials

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 configuration allows for efficient operation at very low temperatures with minimal energy consumption, simplifying the device configuration and reducing the size of the heat exchanger, thereby improving the overall performance of the NMR analysis device.

Implementation Method 1

the turbine having a geometry such that it allows an isentropic expansion of a third fluid M3 which passes through it

Methodology Applied
Scientific EffectIsentropic expansion: Brayton Cycle

Implementation Method 2

first and second exchangers are counter-current exchangers between the first, second and third high-pressure gas streams M1, M2, M3 and the fourth, sixth and seventh gas streams M4, M6, M7

Methodology Applied
Scientific EffectCounter-current heat exchange: Heat Exchanger

Implementation Method 3

The invention also relates to a method for operating an NMR analysis device comprising a circuit including an NMR analysis probe and a cryostat connected by a cryogenic line

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 4

NMR analysis device comprising a probe, a compression module and a second heat exchanger

Methodology Applied
Scientific EffectGas compression: Gas Compressor

Data Source

PatentEP2939041B1Probe, device and method for nuclear magnetic resonance analysis with magic-angle spinning
Publication Date: 2020.02.19 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2939041B1 patent drawingFigure 1
  • EP2939041B1 patent drawingFigure 2A
  • EP2939041B1 patent drawingFigure 2B

AI summary

The invention relates to an NMR analysis device (7) comprising an NMR analysis probe (9) and a cryostat (8) which are connected by a cryogenic line (16), the probe (9) comprising: a frame; a sample holder (12) which includes a rotor (31) and can receive a sample of material (15) to be analysed; a bearing (13) for guiding the rotation of the sample holder (12) in relation to the frame. The device also comprises a compression module (10) and a cryocooler (11), both disposed in the cryostat (8), said cryocooler being upstream of the compression module. In addition, the analysis device (7) comprises a first element (22) for channeling a third gas flow (M3) of fluid towards a turbine (14) and a second element (21) for channeling a second gas flow of fluid (M2) towards the bearing (13), said bearing (13) being of the aerostatic or aerodynamic type.