Reduced size fluid transfer and depressurization apparatus, control, and associated methods

An apparatus to compress a fluid, the apparatus comprising:

• a first casing to define an actuation cylinder;
• a second casing to define a compression cylinder;
• first threaded rods to removably couple the first casing between a first inner end plate and a first outer end plate;
• second threaded rods to removably couple the second casing between a second inner end plate and a second outer end plate;
• a ring coupled between the first and second inner end plates, the ring including one or more cutouts;
• a rod slidably coupled between the actuation cylinder and the compression cylinder;
• and
• a piston coupled to the rod at an end of the rod, the end of the rod in the compression cylinder, the piston slidable relative to the compression cylinder to compress the fluid therein.

A method comprising:

• coupling a first inner end plate and a first outer end plate to a first casing via first threaded rods, the first casing to define an actuation cylinder;
• coupling a second inner end plate and a second outer end plate to a second casing via second threaded rods, the second casing to define a compression cylinder;
• coupling a ring between the first inner end plate and the second inner end plate, the ring including one or more cutouts;
• slidably coupling a rod in the actuation cylinder and the compression cylinder;
• coupling a first piston at a first end of the rod, the first end in the actuation cylinder;
• and
• coupling a second piston at a second end of the rod, the second end in the compression cylinder.