Reciprocating piston pump comprising a housing defining a first chamber and a second chamber cooperating with a first piston and a second piston to define a third chamber and a fourth chamber

A pump system comprising:

• a housing defining a first internal volume and a second internal volume;
• a first piston positioned to separate the first internal volume into a first chamber and a second chamber;
• a second piston positioned to separate the second internal volume into a third chamber and a fourth chamber, wherein the first chamber and the third chamber are configured to selectively receive a first fluid from a first fluid source, and wherein the second chamber and the fourth chamber are configured to selectively receive a second fluid from a second fluid source;
• a directional control valve (DCV) fluidly coupled to the second chamber and the fourth chamber, the DCV repositionable between (a) a first position where the DCV is configured to fluidly couple the second chamber to the second fluid source and (b) a second position where the DCV is configured to fluidly couple the fourth chamber to the second fluid source;
• and
• a relief valve fluidly coupled to the second chamber through a sensing line, the relief valve configured to supply the second fluid to the DCV through an orifice in response to a pressure within the sensing line exceeding a shift pressure to move the DCV from the first position to the second position.

A pump system comprising:

• a housing defining a first internal volume and a second internal volume;
• a first piston positioned to separate the first internal volume into a first chamber and a second chamber;
• a second piston positioned to separate the second internal volume into a third chamber and a fourth chamber;
• a directional control valve (DCV) fluidly coupled to the second chamber and the fourth chamber;
• a first relief valve fluidly coupled to the DCV via a first control line and the second chamber via a first sensing line;
• a first orifice positioned along the first sensing line;
• a second relief valve fluidly coupled to the DCV via a second control line and the fourth chamber via a second sensing line;
• and
• a second orifice positioned along the second sensing line;
• wherein the DCV is repositionable between (a) a first position where a fluid flows to the DCV from the fourth chamber and (b) a second position where the fluid flows to the DCV from the second chamber;
• and wherein the first relief valve is configured to move the DCV from the first position to the second position in response to a pressure within the first sensing line exceeding a shift pressure.