Frame for fluid machines

Reciprocating compressor for compressible fluids, comprising a frame (10) bearing one or more cylinders (12) moving inside each of which, with a reciprocating movement, is a piston operated by a crankshaft (14), the fluid to be compressed by said compressor being introduced into each cylinder (12) through one or more suctioning pipes (18), while the fluid compressed by said compressor being ejected from said cylinder (12) towards one or more discharge pipes (18′), characterised in that said frame (10) is made up of one or more modules (20) of the same size and shape, within each one of said modules (20) being provided a single chamber (16) adapted to accommodate the crank mechanisms of each of said cylinders (12), each of said modules (20) being further provided with a pair of opposite side walls (22, 24) and with one or more fixing means (26) which allow rigid coupling to each other, adjacently arranging their respective side walls (22, 24), of two or more of said identical modules (20) for providing a frame (10) for reciprocating compressors provided with two or more cylinders (12).