Patent ID: 8840377

Claim:
A fluid compressor comprising: a first compression chamber of a first volume; a compressed fluid outlet conduit coupled to the first compression chamber; a second compression chamber of a second, larger volume extending concentrically around the first compression chamber; a third compression chamber of a third volume, larger than each of the first volume and the second volume, the third compression chamber extending concentrically around the first compression chamber and being part co-linear with the second compression chamber; a piston mounted for linearly reciprocating movement, the piston comprising a piston sleeve extending concentrically around a central piston rod, a first piston head at a distal end of the piston sleeve movable to compress fluid within the first compression chamber, and a second piston head at a distal end of the piston sleeve separating the second and third compression chambers, the second piston head being movable to compress fluid within the second compression chamber and the third compression chamber; actuation means operable to drive the piston, whereby as the piston is driven in a first linear direction fluid in the first and third compression chambers is compressed and compressed fluid from the third compression chamber is delivered to the second compression chamber, and, simultaneously, any gas in the first compression chamber is forced out of the first compression chamber and through the compressed fluid outlet conduit into an external gas storage vessel, and whereby as the piston is driven in the opposite direction fluid enters the third compression chamber, and any fluid in the second compression chamber is compressed and any fluid from the second compression chamber is forced out of the second compression chamber, and delivered into the first compression chamber; and a stator defining a second stator chamber extending concentrically around a first stator chamber, the piston and the stator together defining the fluid compression chambers, the first stator chamber forming the first fluid compression chamber and the second and third compression chambers comprise parts of the second stator chamber defined by the piston and one or more walls of the second stator chamber, wherein the second fluid compression chamber comprises the volume of the second stator chamber between an outermost surface of the piston sleeve, an external wall of the second stator chamber and part of one side of the second piston head, the third fluid compression chamber comprising the volume of the second stator chamber between the other side of the second piston head and the walls of the second stator chamber.