Fluid compression apparatus and method

A fluid compression apparatus with a plurality of compression stages, the fluid compression apparatus further comprising:

• a sealed enclosure configured to contain a bath of cryogenic fluid having a liquid phase, the upper part of sealed the enclosure being configured to contain a gas headspace;
• a first compression chamber;
• a second compression chamber;
• an intake system that communicates with the first compression chamber and is configured to allow fluid for compression to enter said first compression chamber;
• a transfer system that communicates with the first and second compression chambers and is configured to allow the transfer of fluid from the first compression chamber to the second compression chamber;
• and
• a movable piston configured to ensure the compression of the fluid in the first and second compression chambers;
• a discharge orifice that communicates with the second compression chamber and is configured to allow compressed fluid to leave;
• the second compression chamber being delimited by a portion of the body of the piston and fixed wall of the apparatus;
• the piston being able to translate in a first longitudinal direction,
• wherein the intake system comprises one or more valves configured to ensure that fluid for compression enters the first compression chamber during an intake phase and to prevent fluid from leaving in the compression phase;
• a second discharge orifice configured to allow communication between the first compression chamber and the bath so as to allow surplus liquid trapped in the first compression chamber to leave during a compression movement of the piston in the first compression chamber;
• and
• a discharge valve configured to control the discharge of liquid via the discharge orifice and to prevent fluid from entering the compression chamber via the discharge orifice,
• wherein the discharge orifice communicates with the enclosure via at least one discharge duct emerging in the enclosure in the bath so as to be situated in and/or above the bath of the enclosure.