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:
Aug. 16, 1988
Filed:
Feb. 12, 1987
Francis Cuny, Mezy-sur-Seine, FR;
Hugues Vermeille, Meylan, FR;
Jean Arnault, Saint-Nazaire-les-Eymes, FR;
L'Air Liquide, Paris, FR;
Abstract
Process for controlling the flow of a fluid through a valve having a given section and a movable valve member, in which the pressures of the fluid which are upstream P.sub.upstream and downstream P.sub.downstream of the valve and the position d of the valve member are measured, then the real flow Q.sub.real of the fluid is calculated and compared with a set value Q.sub.0, the difference signal Q.sub.real -Q.sub.0 commanding the displacement of the valve member in the desired direction, said process comprising effecting the real flow calculation by measuring the ratio R=P.sub.upstream /P.sub.downstream which is compared with a predetermined value R and calculating the product Q.sub.sonic =k.times.P.sub.upstream .times.d so that when R>R.sub.0, the product Q.sub.sonic is directly compared with a set value Q.sub.0, the difference signal Q.sub.sonic -Q.sub.0 commanding the displacement of the valve member in the desired direction whereas, when R<R.sub.0, the ratio R is converted into a digital signal whose value corresponds to the address of a memory whose content is converted into an analog correction signal which, after multiplication by Q.sub.sonic, represents a value proportional to the flow Q.sub.subsonic of the fluid at the subsonic rate, this value Q.sub.subsonic being then compared with the set value Q.sub.0, the signal Q.sub.subsonic -Q.sub.0 commanding the displacement of the valve member in the desired direction.