Converting a pump for use in supercritical fluid chromatography
First Claim
1. A method for converting a pump for use in a combined flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid;
- and a relatively incompressible liquid, comprising;
controlling pressure of a first flow stream containing a highly compressed gas, compressible liquid, or supercritical fluid, by maintaining an elevated pressure rate after said outlet of said pump but prior to joining a second flow stream of a relatively incompressible liquid;
pumping of said first flow stream consisting of a pure fluid resulting in delivery of a controllable flow rate of said first flow stream at a constant compressibility compensation without the need for dynamically compensating said pump for compressibility changes in said first flow stream.
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0 Petitions
Accused Products
Abstract
A method and apparatus for converting a pump for use in a flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid wherein the pump delivers a compressible fluid against a back-pressure regulator which in turn delivers a controllable flow rate downstream of the regulator without performing variable compressibility compensation adjustments on the pump. By using a pressurized source of compressible fluid combined with isocratic conditions, the delivery pressure from the pump is controlled at a rate higher than the downstream gradient with the back-pressure regulator, and an inexpensive pump may be used in place of specialized, expensive pumps and compressibility compensation systems for use in stems operating at or near supercritical fluid levels of compressible fluids. Significant capital and operating laboratory costs are saved through a simpler and cheaper system for accurately delivering compressible fluids into mobile phase flow streams.
9 Citations
24 Claims
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1. A method for converting a pump for use in a combined flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid;
- and a relatively incompressible liquid, comprising;
controlling pressure of a first flow stream containing a highly compressed gas, compressible liquid, or supercritical fluid, by maintaining an elevated pressure rate after said outlet of said pump but prior to joining a second flow stream of a relatively incompressible liquid;
pumping of said first flow stream consisting of a pure fluid resulting in delivery of a controllable flow rate of said first flow stream at a constant compressibility compensation without the need for dynamically compensating said pump for compressibility changes in said first flow stream. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- and a relatively incompressible liquid, comprising;
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8. A method for converting a pump for use in a combined flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid;
- and a relatively incompressible liquid, comprising;
controlling inlet pressure to a pump of a first flow stream of a highly compressed gas, compressible liquid or supercritical fluid;
controlling temperature of said first flow stream;
pumping of said first flow stream, consisting of a pure fluid, against an elevated pressure rate resulting in delivery of a controllable flow rate of said first flow stream at a constant compressibility compensation without the need for dynamically compensating said pump for compressibility changes in said first flow stream. - View Dependent Claims (9, 10, 11, 12, 13, 14)
- and a relatively incompressible liquid, comprising;
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15. An apparatus for converting a pump for use in a combined flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid;
- and a relatively incompressible liquid, comprising;
means for controlling pressure of a first flow stream containing a highly compressed gas, compressible liquid, or supercritical fluid, by maintaining an elevated pressure rate after said outlet of said pump but prior to joining a second flow stream of a relatively incompressible liquid;
means for pumping of said first flow stream consisting of a pure fluid resulting in delivery of a controllable flow rate of said first flow stream at a constant compressibility compensation without the need for dynamically compensating said pump for compressibility changes in said first flow stream. - View Dependent Claims (16, 17, 18, 19)
- and a relatively incompressible liquid, comprising;
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20. An apparatus for converting a pump for use in a combined flow stream containing a mixture of highly compressed gas, compressible liquid or supercritical fluid;
- and a relatively incompressible liquid, comprising;
a pressurized first flow stream source of a pure fluid of compressed gas, compressible liquid or supercritical fluid; and
a pump to deliver said flow stream to a column after mixing with a second flow stream containing a relatively incompressible liquid; and
a back-pressure regulator device installed downstream of said pump and set to deliver said first flow stream at a pressure above any point in the gradient downstream of said back-pressure device; and
wherein the flow rate of said pump is controllable while delivers said first flow stream at a fixed pressure through said back-pressure regulator without performing dynamic compressibility compensation adjustments to said pump. - View Dependent Claims (21, 22, 23, 24)
- and a relatively incompressible liquid, comprising;
Specification