Positive displacement pump as well as a the positive displacement pump for the metering device having at least one free-flowing component

摘要

The invention relates to a positive-displacement pump (1), comprising a cylinder (1a, 1b), inside of which a piston (4) can be moved in a reciprocating manner by means of a drive (3, 7, 8). A seal surrounds the piston (4) and tightly rests against the outer wall of the piston (4) and against the inner wall of the cylinder (1a, 1b), and the seal subdivides the cylinder into a first and a second space (5, 6). The first space (5) filled with a medium is connected to a connecting line (10) via which the medium can be forced out of or delivered into this space (5) of the cylinder by the movement of the piston (4). Said seal is a rolling diaphragm (9, 30).