Thermally-sensitive type flow meter having a high accuracy
US5703288A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 17, 1996 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | Jul 17, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P5/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A thermally-sensitive type flow meter measures a flow rate with a high accuracy by eliminating a noise generated in a source voltage. The flow meter includes a sensor chip comprising a substrate carrying sensing elements. First and second resistors are provided on first and second bridges formed over a depression formed on the substrate. The first bridge is positioned on an upstream side and the second bridge is positioned on a downstream side. The first and second resistors generate a heat by the same voltage source. First and second temperature measuring resistors are provided adjacent to the first and second resistors, respectively, to measure a temperature of the first and second resistors. Third and fourth temperature measuring resistors are provided for measuring the temperature of the fluid. A temperature control unit, including the first, second, third and fourth temperature measuring resistors, controls a temperature of each of the first and second resistors to be constant. A flow rate of the fluid is determined based on a voltage difference between a first voltage applied to the first resistor and a second voltage applied to the second resistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.