A method for metering two or more liquids in controlled proportions

摘要

A method for metering two or more liquids in a liquid supply system comprising a plurality of solvent supply lines (104, 105, 106, 107, fig 1), each connected with a reservoir 800, 801, 802, 803, and a proportioning valve 804 interposed between the solvent supply lines and a pumping unit. A first liquid is drawn into the pumping unit via a first solvent supply line, and one or more switching points of time are determined, for switching between different solvent supply lines. The switching points are determined so that the liquid supplied to the pumping unit is in a predefined pressure range. Pressure transducers 807, 826 may be provided, which may be connected to a controller (806, fig 8) for determining suitable switching points. A mixture of liquids in the pumping unit may be transferred to an auxiliary chamber (911, fig 9), and from the auxiliary chamber back to the pumping unit before the blended liquid is delivered to the pump outlet. The method may be used for supplying liquid to a liquid chromatography system.