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. 20, 1978
Filed:
Jun. 13, 1977
Edwin L Karas, Sharon, MA (US);
Raymond Annino, Coldon, NY (US);
Richard W Kalinoski, East Providence, RI (US);
The Foxboro Company, Foxboro, MA (US);
Abstract
A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration. The orifice and capillary pressure signals are combined subtractively by means of a balanceable force-bar arrangement to which the pressure signals are applied by bellows of predetermined relative sizes, and which is automatically maintained in balanced condition by a rebalance bellows operated by a pneumatic nozzle-flapper feedback device producing the detector output signal.