Zero point compensating circuit
US5076099A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1990 |
| Grant date | Dec 31, 1991 |
| Priority date | — |
| Expiry date | Aug 7, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P21/025
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A zero point compensating circuit for a microbridge flow meter including an upstream thermal sensor means, a downstream thermal sensor means and a heater means located between said upstream and downstream thermal sensor is provided which comprises a first switch coupled to said heater for turning on and off the same and a current supply circuit coupled to said upstream and downstream thermal sensors for selectively supplying the same with a first current when said first switch is closed and a second current larger than said first current when said first switch is opened such that said upstream and downstream thermal sensors reach a temperature to which they are heated when said heater is on in no flow condition. Thus, an offset caused by discrepancy in the resistance value and thermal coefficients of resistance (TCR) of the upstream and downstream temperature sensors can be removed by the above circuit, thereby making it possible to achieve a precise measurement of small flow rates of a fluid of interest.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.