EP0489474A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Laser apparatus for measuring the velocity of a fluid
Assignee: CISE Centro Informazioni Studi e Esperienze SpA
•
Filing: 1991-12-03
•
Granted: —
•
Expires: 2011-12-03
Abstract
Abstract In a laser apparatus for measuring the velocity of a fluid, a measurement laser light beam (M) fed into the fluid and scattered by a particle within the fluid is made to interfere with a reference laser light beam (R) to generate an interference signal based on the velocity of the particle; the apparatus comprises a low-coherence laser source (10) and interferometric means (11, 12) which split the light beam of the laser source (10) into the stated reference light beam (R) and measurement light beam (M), and cause the reference light beam (R) derived from the laser source (10) to interfere with the backscattered component resulting from the scattering of the measurement light beam (M).
Inventors
- 👤 Mario Martinelli
- 👤 Valeria Gusmeroli
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 23:06
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/66; G01F1/661; G01P; G01P5/00; G01P5/26
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
106 words
A laser apparatus for measuring the velocity of a fluid, in which a measurement laser light beam fed into the fluid and scattered by a particle within the fluid is made to interfere with a reference laser light beam to generate an interference signal based on the velocity of the particle, characterised by comprising a low-coherence laser source and interferometric means which split the light beam of said laser source into said reference light beam and said measurement light beam, and cause the reference light beam derived from the laser source to interfere with the backscattered component resulting from the scattering of the measurement light beam.
Claim 2
Dependent Claim
51 words
A laser apparatus as claimed in claim 1, wherein the interferometric means comprise an optical component able to vary the optical path of the reference light beam, to measure the velocity of a plurality of particles encountered within the fluid by the measurement light beam at a series of measurement points.
Claim 3
Dependent Claim
18 words
A laser apparatus as claimed in claim 2, wherein said optical component consists of a movable reflecting element.
Claim 4
Dependent Claim
41 words
A laser apparatus as claimed in claim 2, wherein said optical component comprises a plurality of reflecting elements, each of which determines an optical path for the reference light beam which is different from that determined by the other reflecting elements.
Claim 5
Dependent Claim
110 words
A laser apparatus as claimed in claim 3, wherein the interferometric means comprise a first directional coupler which splits the light beam emitted by the source into said reference light beam and said measurement light beam, the reference light beam being fed to said reflecting element, the measurement light beam being fed to a probe which projects it into the fluid and collects said backscattered component, the reference light beam reflected by the reflecting element and the backscattered component being fed to a second directional coupler to generate the interference signal, the connection between the laser source, the first and second directional coupler and the probe being via optical fibres.
Claim 6
Dependent Claim
43 words
A laser apparatus as claimed in claim 5, wherein the probe comprises a beam splitter which feeds the measurement light beam into the fluid and collects said backscattered component, feeding it to a deflection prism which directs it to the second directional coupler.
Claim 7
Dependent Claim
66 words
A laser apparatus as claimed in claim 5, wherein the probe comprises a collimation and collection element which feeds the measurement light beam into the fluid and collects said backscattered component and directs it to said first directional coupler which directs it to the second directional coupler, the connection between the first directional coupler and the collimation and collection element being via a single optical fibre.
Claim 8
Dependent Claim
36 words
A laser apparatus as claimed in claim 5, wherein the reference light beam is fed to the reflecting element via a beam splitter which also feeds the reflected reference light beam to the second directional coupler.
Claim 9
Dependent Claim
21 words
A laser apparatus as claimed in claim 8, wherein a modulator is interposed between the beam splitter and the reflecting element.
Claim 10
Dependent Claim
16 words
A laser apparatus as claimed in claim 8, wherein the movable reflecting element is a mirror.
Claim 11
Dependent Claim
33 words
A laser apparatus as claimed in claim 5, wherein the movable reflecting element is a right prism which deviates the reference light beam from the first directional coupler towards the second directional coupler.
Claim 12
Dependent Claim
22 words
A laser apparatus as claimed in claim 11, wherein a modulator is interposed between the right prism and the second directional coupler.
Claim 13
Dependent Claim
142 words
A laser apparatus as claimed in claim 4, wherein the interferometric means comprise a directional coupler which splits the light beam emitted by the laser source into said reference light beam and said measurement light beam, the reference light beam being fed to a first optical element which produces at its exit a wide light beam directed to a first beam splitter which feeds it to said plurality of reflecting elements, the measurement light beam being fed to a probe which projects it into the fluid and collects said backscattered component, feeding it to a second optical element which produces at its exit a wide light beam and directs it to a second beam splitter, the first beam splitter feeding the wide reference light beam reflected by the reflecting elements to the second beam splitter to generate a plurality of interference signals.
Claim 14
Dependent Claim
43 words
A laser apparatus as claimed in claim 13, wherein the probe comprises a beam splitter which feeds the measurement light beam into the fluid and collects said backscattered component, feeding it to a deflection prism which directs it to said second optical element.
Claim 15
Dependent Claim
63 words
A laser apparatus as claimed in claim 13, wherein the probe comprises a collimation and collection element which feeds the measurement light beam into the fluid and collects said backscattered component, feeding it to the directional coupler which directs it to said second optical element, the connection between the directional coupler and the collimation and collection element being via a single optical fibre.
Claim 16
Dependent Claim
20 words
A laser apparatus as claimed in claim 13, wherein said plurality of reflecting elements form part of a multiple mirror.
Claim 17
Dependent Claim
33 words
A laser apparatus as claimed in claim 1, wherein the interference light signal is decomposed into two identical interference signals out of phase by 180° to effect a differential measurement of the interference.
Claim 18
Dependent Claim
29 words
A laser apparatus as claimed in one of claims 1, 2 and 17, wherein the interference light signal is detected by photoelectric transducers connected to an electronic processor unit.
Claim 19
Dependent Claim
68 words
A laser apparatus as claimed in claim 3, wherein the reflecting element is connected to a translator moved by a motor, the interference signal being detected by photoelectric transducers, an electronic processor unit being provided connected to the motor and transducers, to determine from the interference signal and the position of the reflecting element the velocity of each particle encountered within the fluid by the measurement light beam.
Claim 20
Dependent Claim
36 words
A laser apparatus as claimed in claim 1, for measuring the velocity of the fluid within a pipe, wherein the measurement laser beam is fed into the pipe via a window consisting of a deflection prism.
Claim 21
Dependent Claim
29 words
A laser apparatus as claimed in claim 5 or 13, for measuring the velocity of the fluid within a pipe, wherein said probe is inserted into the pipe wall.
Claim 22
Dependent Claim
28 words
A laser apparatus as claimed in claim 5 or 13, for measuring the velocity of the fluid within a pipe, wherein said probe is inserted into the pipe.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.