Fluid flow detector
US4909078A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1987 |
| Grant date | Mar 20, 1990 |
| Priority date | — |
| Expiry date | Oct 14, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2030/025
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A thermal effect sensing device comprises a semiconductor substrate supporting an insulating layer which has a thin film of platinum deposited on it. Holes are etched through the semiconductor substrate and the insulating layer. The platinum film is shaped to provide a serpentine resistive element suspended over one of the holes. The serpentine element is suspended from the rim of the hole, but is otherwise unsupported. The resistive element has a low thermal mass and there is a low thermal resistance between the element and fluid in the sensor. The sensor senses thermal properties of the fluid in the sensor, such as mass flow or thermal conductivity. A second conductive film is insulatingly deposited on the first film to provide a resistive sensor electrically isolated from a resistive heating element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.