Hydraulic fluid-driven, multicylinder, modular reciprocating piston pump

A hydraulic fluid-driven, multicylinder, modular, reciprocating piston pumping machine, of non-pulsating flow, comprising a plurality of like pumping modules (A,B . . . E) each having one primary cylinder (A1,B1 . . . E1) and one secondary cylinder (A2,B2, . . . E2) coaxially joined to each other by interposition of a bushing (100) through which slides a piston rod (A3,B3 . . . E3) with a piston (A4,B4 . . . E4;

• A5,B5 . . . E5) attached to each of its ends, wherein:
• each secondary cylinder (A2,B2 . . . E2) is provided, at the end opposed to the bushing (100) with suction and delivery valves that connect the individual modules to a suction distributor conduit (3) and to a delivery collector conduit (4) respectively, both of these latter conduits being connected to their respective individual modules via shut-off valves (A17,B17 . . . E17;
• A16,B16 . . . E16);
• each primary cylinder (A1,B1 . . . E1) has the end opposed to the bushing closed by a valve manifold (A11, B11 . . . E11), all of the individual module's valve manifolds being interconnected through a pressurized hydraulic fluid distributor conduit (5) through which pressurized hydraulic fluid is supplied by at least one hydraulic pump (1,2), the pressurized hydraulic fluid being supplied to the primary cylinder of each module for advancing the pistons through a forward stroke;
• and
• a hydraulic fluid chamber (A18,B18 . . . E18) formed in each primary cylinder by a back side of the piston, said bushing (100), the rod's surface and the cylinder's interior wall, communicates by means of a distributor-collector conduit (11) with all such chambers (A18,R18 . . . E18) of the rest of the modules for returning the pistons through a return stroke, said distributor collector conduit (11) being provided with at least one hydro-pneumatic accumulator (12),
• characterized in that said hydro-pneumatic accumulator (12) is connected via the distributor-collector conduit (11) to a relatively large, supplementary gas reservoir (23) constituting a volumetric compensator for all the hydraulic fluid contained in all said chambers (A18,B18 . . . E18), and at the same time providing pressure for the return stroke of the pistons (A4,B4 . . . E4) at a return stroke speed which is variable independently of the forward stroke speed.