Patent ID: 8535016
Filing Date: 2013-09-17
Classification: F04B,G01N

Abstract:
1. A flow control system for delivering a fluid in a chromatography apparatus comprising: a high pressure pump including: a primary piston for intaking a fluid from a fluid source; and an accumulator piston for receiving the fluid from the primary piston and delivering the fluid in the chromatography apparatus, each piston having a velocity and pressure associated therewith, wherein during a transfer portion of a pump cycle of the high pressure pump, the primary piston refills the accumulator piston and delivers the fluid to the chromatography apparatus; and an instantaneous closed loop feedback control only on the accumulator pressure substantially only during the transfer portion for modifying the accumulator velocity to maintain a system pressure substantially equal to an expected pressure to substantially eliminate an effect created by adiabatic heating at high pressure, wherein during the transfer portion, a nominal accumulator piston velocity profile has an initial linear descending portion, a second steady state portion, and a third linear ascending portion, and the instantaneous closed loop feedback control only modifies the initial linear descending portion and the second steady state portion.