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. 18, 1998
Filed:
Jan. 23, 1997
Shingo Gomi, Tokyo, JP;
Hirokazu Kitami, Tokyo, JP;
Takashi Endo, Tokyo, JP;
Kenichi Matsuoka, Tokyo, JP;
Kimihiro Ichinose, Tokyo, JP;
Osamu Futagawa, Tokyo, JP;
Seiji Kobayashi, Tokyo, JP;
Kazuhide Kobayashi, Tokyo, JP;
Oval Corporation, Tokyo, JP;
Abstract
A resonantly drivable straight tube type Coriolis flowmeter which is capable of correcting instrumental errors caused by a change in density and temperature of measurable fluid. A coaxial double tube body that is composed of an inner tube wherein fluid to be measured flows and an outer tube with a balance weight attached thereto for equalizing natural frequencies of the inner and outer tubes is driven at a resonant frequency having a constant amplitude. A change of fluid density causes a change of amplitude ratio of the inner tube and the outer tube, resulting in shifting of an instrumental error. At this time, a resonant frequency detecting circuit detects a resonant frequency without detecting the amplitude ratio. An instrumental error detecting circuit stores a relation between resonant frequencies and fluid densities and a relation between fluid densities and instrument errors and conducts correction of an instrumental error according to the detected resonant frequency. An instrumental error caused by thermal deformation of the inner tube and the outer tube which are different from each other in material and shape can be also corrected by using similar correcting means.