Fluid circulation device, installation and method using such a device

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Solution Overview

Problem

Existing methods for cooling electrical junction boxes in refrigerators or cryogenic liquefiers are inefficient, leading to increased size, weight, manufacturing costs, and leakage risks due to reliance on natural convection and conduction, which are limited by wall thickness and pressure resistance.

Innovation Solution

A fluid circulation device with pressurized cycle gas supply and return lines that circulate a fraction of the cycle gas through the junction box to cool it, using a flow control device and heat exchanger to manage thermal management efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the junction box is cooled by natural convection and conduction through walls, then the cooling method is simple, but the junction box size increases and weight increases

Engineering Contradiction:
Improvecooling system complexityVSAvoidjunction box weight
Core Design Contradiction:
Device complexityVSWeight of stationary object

Solution Approach 1:

The patent applies pneumatic cooling by circulating pressurized cycle gas through the junction box. The cooling system uses the refrigerant gas already present in the cryogenic device to flow through channels in the junction box, removing heat efficiently without requiring large thermal mass or complex external cooling infrastructure.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The cycle gas serves multiple functions: it cools the compression element, maintains pressure in the cryogenic system, and now also cools the junction box. By using the same refrigerant for multiple cooling purposes, the system avoids additional weight from separate cooling systems while maintaining effectiveness.

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

2Device complexity

If the junction box is cooled by natural convection and conduction through walls, then the cooling method is simple, but manufacturing cost increases

Engineering Contradiction:
Improvecooling system complexityVSAvoidmanufacturing cost
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent integrates pneumatic cooling channels directly into the junction box structure, allowing the pressurized cycle gas to flow through internal passages. This approach eliminates the need for separate external cooling systems and reduces manufacturing complexity while improving cooling efficiency.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The cooling function is merged with the existing cycle gas circulation system. The same pressurized refrigerant that cools the compression element is also directed through the junction box, combining multiple cooling functions into a single integrated system that reduces overall manufacturing cost.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If the wall thickness is increased to withstand pressure, then pressure resistance improves, but cooling by conduction is limited

Engineering Contradiction:
Improvepressure resistanceVSAvoidcooling efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent overcomes the conduction limitation by introducing pneumatic cooling through internal channels. The pressurized cycle gas flows directly through the junction box, providing efficient convective cooling that works effectively even with thicker pressure-resistant walls, thus decoupling structural strength from thermal conduction requirements.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The junction box is segmented with internal cooling channels that allow the cycle gas to flow through multiple paths. This segmentation creates direct thermal contact between the cooling gas and the junction box walls, enabling efficient heat removal without relying on conduction through thick pressure-resistant walls.

Inventive Principle:
Principle #1Segmentation

4Temperature

If the junction box size is increased to improve heat management, then cooling capacity improves, but the overall size of the device increases

Engineering Contradiction:
Improveheat management capacityVSAvoiddevice size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent uses pneumatic cooling with pressurized cycle gas flowing through internal channels to achieve efficient heat management within a compact volume. The high-velocity gas flow provides superior heat transfer coefficients that allow effective cooling without increasing the junction box size or overall device volume.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the cooling parameter from passive conduction to active convective cooling with pressurized gas. This parameter change dramatically improves heat transfer efficiency, allowing the same cooling capacity to be achieved in a much smaller volume compared to natural convection or conduction-based systems.

Inventive Principle:
Principle #35Parameter changes

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 provides compact and efficiently cooled junction boxes with reduced size and weight, lower manufacturing costs, and enhanced thermal behavior while maintaining pressure resistance.

Implementation Method 1

a pressurized cycle gas supply line having a first end connected to a portion of the circuit in which the cycle gas is at a pressure greater than the minimum pressure and a second end communicating with the inside of the junction box... configured to take a fraction of the cycle gas flowing in the circuit to circulate it in the junction box in order to cool the latter

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Data Source

PatentEP4490453B1Fluid circulation device, installation and method using such a device
Publication Date: 2025.11.12 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP4490453B1 patent drawingFigure 1~2
  • EP4490453B1 patent drawingFigure 3~4
  • EP4490453B1 patent drawingFigure 5

AI summary

The invention relates to a fluid circulation device comprising a casing (2) containing an electric machine (3), a cycle-gas circuit (5) subjecting the cycle gas to a change between a minimum pressure and a maximum pressure, a cycle-gas drive member (4) rotationally coupled to the electric machine (3), an electrical junction box (6) through which there passes electric circuitry (8) having one end connected to the electric machine (3) and one end connected to an electrical coupling (7) open to the outside, the device (1) comprising a cycle-gas conveying pipe (15) connected to a portion of the circuit (5) in which the cycle gas is at a pressure higher than the minimum pressure and to the inside of the junction box (6), the junction box (6) comprising a passage (9) for communicating with the inside of the casing (2), the conveying pipe (15), the passage (9) and the return pipe (25) being configured to bleed a fraction of the cycle gas from the circuit (5) and pass it through the junction box (6) with a view to cooling same before returning to the circuit (5).