Error correcting Coriolis flowmeter
US5796012A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 1997 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Jan 23, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/849
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.