The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 19, 1995
Filed:
Mar. 31, 1994
Robert Henderson, Avondale, PA (US);
Edwin Wikfors, Landenberg, PA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
The effect of barometric pressure variation on the retention time stability of a chromatographic analytical system is compensated by active control of the amount of fluid flow by way of a fluid flow controller, preferably in the form of an electronic pressure control system. Control signals are derived by: receiving data representative of a desired operating condition parameter, such as column inlet pressure; sensing actual operating condition parameters such as inlet pressure p.sub.i and barometric pressure p.sub.atm ; determining a desired average linear velocity of the fluid flow according to the desired operating system parameter; determining an actual average linear velocity of the fluid flow according to the sensed plurality of actual operating condition parameters; and controlling, as a function of a predetermined relationship of the desired average linear velocity to the actual average linear velocity, the amount of fluid flow to cause the actual average linear velocity to substantially equal the desired average linear velocity.