Solvent pumping system

摘要

A continuous-delivery fluid pumping system comprising independently-driven pump units, each pump unit having outlet valving which prevents backflow of fluid from (1) the outlet side of the pumping system back to the pump cylinder, and (2) from the cylinder back to the inlet side of the pumping system. A pressure sensor is positioned within each pump unit, permitting a pump unit which has been refilled off-line to perform compression of its cylinder contents without perturbation of the on-line process, and which further permits discrimination of the point in the compression cycle where compression has been completed and fluid delivery to the system will commence.