Flow rate sensor
US6240775A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1998 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Oct 27, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/6842
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A flow rate sensor comprises: a main fluid passage for a fluid to flow therealong; a detecting pipe conduit coaxially disposed in the main fluid passage; a temperature sensing element for sensing the temperature of the fluid; a flow rate sensing element including a flow rate detecting resistance made of a thermo-sensitive electrically resistant material, the flow rate detecting element being disposed in the main fluid passage in a manner such that the flow rate detecting resistance is exposed to the fluid flowing therethrough; and a control circuit for controlling an electric current flowing to the flow rate detecting resistance such that the temperature of the flow rate detecting resistance may be maintained at a predetermined value which is higher to some extent than a fluid temperature detected by the temperature sensing element. The main fluid passage involves a converged section whose passage cross sectional area becomes gradually smaller towards the downstream side thereof. At least one portion of an inner surface of the converged section cut by a plane containing the central axis of the main fluid passage is formed by a generally three dimensional curved surface. The inlet o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.