Patent References 3917531 3922957 Liquid chromatography pumping system with compensation means for liquid compressibility Method and apparatus for reducing the transient effects of liquid compressibility in a liquid chromatography system Fluid pump mechanism Programmable solvent delivery system and process Liquid composition control Fluid composition and volumetric delivery control Pumping apparatus for delivering liquid at high pressure Chromatographic system with mixer InventorAssigneeApplicationNo. 233555 filed on 01/20/1999US Classes:210/198.2, Chromatography210/101, Proportionate feed means210/656ChromatographyExaminersPrimary: Therkorn, Ernest G.Attorney, Agent or FirmInternational ClassB10D 015/08AbstractA fluid delivery method and apparatus implementing active phasing to actively restore the substantially exact mechanical positions of driven components in a delivery system in order to precisely reproduce the mechanical signature and hydraulic characteristics of the system from run to run without perturbing output flow. The delivery system is configured to intelligently drive pump pistons to a known position and to delivery fluid(s) at a known pressure, and includes a plurality of pump modules each including motor driven syringes having respective pistons configured to reciprocate under control of a control mechanism. Pump phasing is accomplished through a mechanism of compensation delivery of the syringes. An independent, motor-driven syringe of any given pump in a plurality of pumps in a system has the ability to act as a delivering syringe to maintain a prescribed output flow while one other syringe of each of the plurality of pumps is repositioned under load. With the delivering syringe maintaining output flow, the syringe which is repositioning, i.e. being phased, can substantially simultaneously arrive at a destination position and at a destination pressure.Field of SearchChromatographyIncluding liquid flow diversion Fluid pressure responsive Proportionate feed means Chromatography Plural pumps having separate drive motors, supply sources, or delivery destinations Pumps in parallel flow paths with common inflow or outflow Having means sensing condition in common inflow or outflow line With control of plural pump drive motors With additional means sensing condition of one pump or path Sequential starting or stopping of pumps Alternating sequences With condition responsive control of pump fluid valve Responsive to change in rate of pump fluid flow Responsive to pump fluid pressure PROCESSES | |