An apparatus for dispensing accurate volumes of liquid drawn from a reservoir to which the apparatus is attachable comprises a plunger for drawing the liquid past a non-return inlet valve into a barrel on a forward stroke of the plunger in the barrel and for expelling the liquid past a non-return delivery...http://www.google.de/patents/US4074831?utm_source=gb-gplus-sharePatent US4074831 - Liquid metering device with adjustable stops
