Reciprocating piston pump for conveying a medium

A reciprocating piston pump for conveying a medium, comprising:

• at least one pump module;
• a drive;
• and
• an auxiliary reciprocating piston;
• wherein the at least one pump module includes a cylinder head, a cylinder and a reciprocating piston;
• wherein the reciprocating piston has a reciprocating piston head with a reciprocating piston head surface;
• wherein the cylinder head, the cylinder and the reciprocating piston head form a conveying chamber;
• wherein the reciprocating piston is designed for converting a drive movement of the drive into a conveying stroke movement and into a suctioning stroke movement of the reciprocating piston in the cylinder along a longitudinal axis;
• wherein the cylinder head, the cylinder and the reciprocating piston are designed for converting the conveying stroke movement into a conveying of a medium out of the conveying chamber by making the conveying chamber smaller;
• wherein the auxiliary reciprocating piston is arranged between the drive and the reciprocating piston and has an auxiliary reciprocating piston head with an auxiliary reciprocating piston head surface;
• wherein the cylinder, the reciprocating piston and the auxiliary reciprocating piston head form a lubricating chamber for a lubricating medium for lubricating contact surfaces between the cylinder and the reciprocating piston and contact surfaces between the cylinder and the auxiliary reciprocating piston;
• wherein the cylinder, the reciprocating piston and the auxiliary reciprocating piston are designed for converting the drive movement into an auxiliary conveying stroke movement and into an auxiliary suctioning stroke movement of the auxiliary reciprocating piston in the cylinder along the longitudinal axis and for converting the auxiliary conveying stroke movement of the auxiliary reciprocating piston into the conveying stroke movement of the reciprocating piston via the lubricating medium in the lubricating chamber;
• and
• wherein the auxiliary reciprocating piston head surface is smaller than the reciprocating piston head surface, so that, during the auxiliary conveying stroke movement, a pressure of the lubricating medium in the lubricating chamber is greater than a pressure of a medium in the conveying chamber.