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:
Jun. 04, 1996
Filed:
Dec. 30, 1994
Tak K Wang, Havertown, PA (US);
Edwin E Wikfors, Landenberg, PA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
In the preferred embodiment, the invention is embodied in the pneumatic manifold of a gas chromatograph to provide current operating temperature and pressure compensation of inlet fluid flow. The pneumatic manifold comprises a plurality of thermally coupled mass flow, pressure and temperature sensors which generate signals related to mass flow of the fluid, fluid pressure and sensor temperature prior to the introduction of the fluid into the column. A plurality of firmware models which characterize the effects of current operating temperature and pressure variations on the mass flow and pressure sensors are stored in computer memory. Compensation is provided by determining the desired flow into the inlet, determining the control signal required to achieve this values at current operating conditions, determine the current operating conditions, implementation of firmware models to determine the effects on flow due to changes in current operating conditions and finally, generation of an adjustment to the control signal that nullifies the effects caused by changes in current operating conditions. These steps are repeated continuously to provide closed loop control of the desired detector conditions.