Patent ID: 6532802
Filing Date: 2003-03-18
Classification: B01D,G01F,G01N

Abstract:
An apparatus for providing a liquid whose composition varies with time to a chromatography column, comprising:a) at least two high pressure pumping means, each having an inlet and an outlet, wherein the inlet of each pump is connected to a liquid reservoir; b) a flowmeter disposed at the outlet of each high pressure pumping means, each flowmeter comprising a porous bed of a material, the porous bed having a porosity in the range of about 0.1 to 0.6 and a pore size in the range of about 50 nm to 1 &mgr;m, and pressure measuring means disposed at the inlet and outlet of the porous bed for measuring the pressure drop through the porous bed; c) a feedback control means for measuring the pressure drop through each flowmeter and providing an error signal to said high pressure pumping means to adjust the pressure therefrom and thereby adjust the flow rate of the liquid from each high pressure pumping means, the error signal derived from the difference between the measured pressure through each flowmeter and a programmed pressure; d) a sample mixing means having an inlet and an outlet, the outlet of each flowmeter is connected to the inlet of the sample mixing means; and e) a chromatography column connected to the outlet of the said sample mixing means.