Chromatographic pumping system
To provide smooth constant flow from a pump, a chromatographic system comprises: a chromatographic column having an inlet; a pump for supplying fluid to the inlet of the chromatographic column; a power means for the pump motor; positive and negative feedback loop means for controlling said power means; means for energizing and said positive and negative feedback control means; said negative feedback control means receiving a signal from said means for measuring flow rate and including means for comparing said signal with said corrected flow rate reference signal while said second feedback loop is energized to generate an error signal controlling said power means; and said positive feedback control means applying an acceleration voltage to said motor from a time a preset period after the initiation of a return stroke of said piston until after a timed duration.