Electromagnetic flow meter removing influence of fluctuation in direct-current offset voltage
US5677496A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 7, 1996 |
| Grant date | Oct 14, 1997 |
| Priority date | — |
| Expiry date | Oct 7, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/60
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electromagnetic flow meter which calculates the electric conductivity of a fluid based on the ratio of an output signal generated when electrodes are grounded through short-circuit resistors Rs.sub.1, Rs.sub.2 to an output signal generated when the electrodes are not grounded, and more accurately corrects a flow measurement using the electric conductivity, characterized in that, for reducing measurement errors due to fluctuation in DC offset voltage accompanied by an on/off operation of the short-circuit switch S1, outputs are measured when the short-circuit switch S1 is on and off in a magnetization state, the output are next measured when the short-circuit switch S1 is on and off in a non-magnetization stage, and the outputs in the non-magnetization state are subtracted from the outputs in the magnetization state, thereby removing the influence of "DC offset voltage fluctuation" occurring accompanied by the on/off operation of the short-circuit switch S1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.