Liquid Hydrogen Compression With Controlled Excess-Liquid Evacuation

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Solution Overview

Problem

Existing fluid compression systems face inefficiencies due to cavitation and vaporization issues during the compression of cryogenic fluids, particularly hydrogen, due to the evacuation of excess liquid from the first compression stage, which leads to pressure loss and thermal input.

Innovation Solution

Incorporation of an evacuation valve and flow retarder system to control the discharge of excess liquid from the first compression chamber, preventing re-entry and minimizing pressure loss through a non-abrupt flow mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If excess liquid is evacuated from the first compression chamber using a simple orifice, then the chamber can be prepared for the next compression cycle, but vaporization gas is generated in the bath due to pressure loss and thermal input

Engineering Contradiction:
Improvecompression cycle efficiencyVSAvoidvaporization gas generation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

An evacuation valve is introduced as an intermediary component between the first compression chamber and the bath. This valve controls the evacuation process, allowing excess liquid to be removed while preventing uncontrolled pressure loss that would cause vaporization. The valve acts as a mediator that enables necessary fluid removal without generating harmful vaporization effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The evacuation valve allows control over the evacuation parameters (timing, rate, and extent of liquid removal). By adjusting these parameters, the system can evacuate excess liquid efficiently while maintaining pressure conditions that prevent vaporization. The valve enables precise parameter control to avoid the harmful effects of uncontrolled evacuation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the evacuation orifice allows free communication between the first compression chamber and the bath, then excess liquid can exit, but fluid may re-enter the compression chamber during compression phase

Engineering Contradiction:
Improveexcess liquid evacuationVSAvoidcompression phase integrity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The evacuation valve serves as an intermediary that selectively controls fluid communication. During the evacuation phase, it opens to allow excess liquid to exit the first compression chamber. During the compression phase, it closes to prevent fluid re-entry, thus maintaining compression integrity. The valve mediates between the need for liquid removal and the need for compression reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The evacuation valve operates periodically, opening during evacuation phases and closing during compression phases. This periodic action ensures that excess liquid is removed when needed while preventing fluid re-entry during compression. The timing-controlled operation maintains both evacuation effectiveness and compression reliability.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a non-return valve is used for evacuation, then fluid re-entry is prevented, but pressure loss occurs during the discharge process

Engineering Contradiction:
Improveprevention of fluid re-entryVSAvoidpressure loss during discharge
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The evacuation valve acts as a controlled intermediary that manages the discharge process. Unlike a simple non-return valve that causes uncontrolled pressure loss, the evacuation valve regulates the discharge rate and timing, minimizing pressure loss while still preventing fluid re-entry. It mediates between the need for reliable one-way flow and the need to conserve pressure energy.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances the performance and volumetric efficiency of liquid hydrogen pumps by maintaining thermodynamic quality and preventing vaporization, ensuring efficient compression without flash vaporization.

Implementation Method 1

a flow retarder configured to attenuate the speed and/or the intensity of the flow of liquid discharged by limiting its pressure drop

Methodology Applied
Scientific EffectFlow retarder mechanism:

Implementation Method 2

a movable piston for compressing the fluid in the first and second compression chambers, the piston being movable in translation in a longitudinal direction

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 3

a sealed enclosure intended to contain a bath of cryogenic fluid comprising a liquid phase, the upper part of the enclosure being intended to contain a gaseous atmosphere

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP4589145A1Apparatus and method for compressing fluid
Publication Date: 2025.07.23 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP4589145A1 patent drawingFigure 1~2
  • EP4589145A1 patent drawingFigure 3~4
  • EP4589145A1 patent drawingFigure 5~6

AI summary

The invention relates to an apparatus (1) and a method for compressing fluid comprising a first (3) and a second compression chamber (3), an intake system (2) in the first chamber (3), a transfer system (6) from the first chamber (3) to the second (4) chamber, a piston (5) for compressing the fluid in the first (3) and second (4) chambers, an orifice (7) for discharging the compressed fluid, the intake system (2) comprising one or more configured valves (2), the apparatus further comprising an evacuation orifice (8) allowing communication between the first compression chamber (3) and the bath (16) to let out excess liquid trapped in the first compression chamber (3) during a compression movement of the piston (5) in the first compression chamber (3),the apparatus comprising a discharge valve (9) configured to control the discharge of liquid via the discharge orifice (8) and to prevent the entry of fluid into the compression chamber (3) via the discharge orifice (8).,