Fiber laser sensor for measuring differential pressures and flow velocities
US6597821B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2001 |
| Grant date | Jul 22, 2003 |
| Priority date | — |
| Expiry date | Jun 25, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L11/025
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a fiber laser pressure sensor 1 which is suitable in particular for measuring differential pressures and flow velocities v1 in oil boreholes. The fiber laser 2 according to the invention comprises two sensor fiber segments 5a, 5b subjected to different pressure loading, in which segments a birefringence proportional to the differential pressure &Dgr;p=p1−p2, and consequently a beat frequency, is induced between the polarization modes or spatial modes in the fiber laser 2. Exemplary embodiments with polarimetric monomode fibers 5a, 5b and/or with elliptical two-mode fibers 5a, 5b are specified. Furthermore, pressure-resistant multichamber sensor housings 25 and wavelength division multiplex arrangements are disclosed for the fiber laser pressure sensor 1. One advantage is that the pressure signal is wavelength-coded and thus highly insensitive to interference. It can be read out directly fiber-optically over large distances between the passively optical sensor head 1 and the optoelectronic measuring device 12, 17. One application concerns the measurement of a flow velocity v1 with the aid of a Venturi tube 23.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.