Control arrangement for controlling a piston pump unit for liquid chromatography

摘要

A control arrangement for controlling a piston pump unit for liquid chromatography, in particular high-performance liquid chromatography, is described. The piston pump unit has at least two piston-cylinder units which operate cyclically in a phase-offset manner and generate, at an outlet port, a predetermined flow of a liquid medium to be delivered. A system pressure is established at the outlet port, irrespective of an associated fluid load resistance. The control arrangement is configured to record the pressure in the cylinder volume of at least a first of the at least two piston-cylinder units. During a measurement phase of the compression phase of the first piston-cylinder unit or during a measurement phase of the decompression phase of the first piston-cylinder unit, the control arrangement stops the drive device for the first piston-cylinder unit for a predetermined time period and in the process records measurement data which characterize the time profile of the pressure.

主权项

1. A piston pump unit for liquid chromatography comprising:
(a) at least two piston-cylinder units configured to generate, at an outlet port, a predetermined flow of a liquid medium at a system pressure, in which each piston-cylinder unit has an independent drive device, (b) a control device configured to
(i) control the independent drive devices for the at least two piston-cylinder units,(ii) compress the liquid medium in a first cylinder of the at least two piston-cylinder units in a compression phase from a starting pressure to the system pressure,(iii) decompress the first cylinder of the at least two piston-cylinder units in a decompression phase,(iv) record pressure values as a function of time in a cylinder volume of at least a first of the at least two piston-cylinder units during a measurement phase,(v) stop the independent drive device for the first piston-cylinder unit for a predetermined time period during the measurement phase, the measurement phase being either a measurement phase of the compression phase of the first piston-cylinder unit or a measurement phase of the decompression phase of the first piston-cylinder unit;(vi) determine a correction dependence to correct a piston movement of at least one of the at least two piston-cylinder units during a compensation phase based on the recorded pressure values as a function of time, and(vii) control the at least one of the at least two piston-cylinder units using the correction dependence during the compensation phase.