Flowmeter for pressure-driven chromatography systems
AssigneeSandia National Laboratories
InventorsPhillip H. Paul, Don W. Arnold
Life of this patent
Estimating the term…
Abstract
A flowmeter for accurately measuring the flowrate of fluids in high pressure chromatography systems. The flowmeter is 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 μm, disposed between a high pressure pumping means and a chromatography column. The flowmeter is provided with pressure measuring means at both the inlet and outlet of the porous bed for measuring the pressure drop through the porous bed. This flowmeter system provides not only the ability to measure accurately flowrates in the range of μL/min to nL/min but also to provide a signal that can be used for a servo loop or feedback control system for high pressure pumping systems.
Claims18
An improved chromatography apparatus in which high pressure pumping means forces a fluid through a chromatography column, wherein the improvement comprises:
- a flowmeter capable of measuring flowrates in the range of μL/min to nL/min interposed between the high pressure pumping means and the chromatography column, said flowmeter comprising a porous bed of a material, wherein the porous bed has a porosity in the range of about 0.1 to 0.6 and pore sizes in the range of about 50 nm to 1 μm, and pressure measuring means disposed at the inlet and outlet of the bed of porous material for measuring the pressure drop through the bed of porous material.
A flowmeter for controlling precisely the delivery of a liquid at flowrates in the range of μL/min to nL/min in a high pressure system, comprising:
- a porous bed of a material, wherein the bed has a porosity in the range of about 0.1 to 0.6 and pore sizes in the range of about 50 nm to 1 μm;
- and
- pressure measuring means disposed at the inlet and outlet of said bed of porous material for measuring the pressure drop through the bed of porous material.
A method for accurately measuring the flowrate of a fluid in a high pressure chromatography system, comprising:
- disposing a flowmeter between the outlet of a high pressure pumping means and the inlet of a chromatography column, wherein the flowmeter comprises 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 μm, and pressure measuring means disposed at the inlet and outlet of the porous bed for measuring the pressure drop through the porous bed.
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 μm, 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.
An apparatus for high pressure chromatography, comprising:
- a substrate fabricated to define a microchannel system disposed thereon, the microchannel system comprising an electrokinetic pump and a chromatography column and disposed therebetween a 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 μm, and pressure measuring means disposed at the inlet and outlet of the porous bed for measuring the pressure drop through the porous bed.
Dependencies are inferred from the claim text.