Method and apparatus for measuring the properties of a liquid
AssigneeF-Lab S.R.L.
InventorsMichele NORGIA, Diego ANDREIS, Fabrizio TESSICINI
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Abstract
The present invention relates to a method and an apparatus for measuring the properties of a liquid that exploit the power modulation a laser light beam undergoes due to the retro-reflection of the laser light beam itself towards the laser cavity from which the laser is generated when this laser light is directed towards a transparent conduit through which the liquid for which the properties are to be measured flows. According to the invention this power modulation is detected by at least one photodiode arranged downstream of the transparent conduit.
Claims16
Method for measuring the properties of a liquid comprising the steps of:
- generating a laser light beam (30) from a semiconductor laser source (3) comprising a laser cavity (32);
- directing said laser light beam (30) towards a conduit (5) transparent to said laser light beam (30) through which a liquid (7) flows, inside said transparent conduit (5) the power of said laser light beam (30) being modulated due to retro-reflection of said laser light beam (30) towards said laser cavity (32) operated by suspended particles moving inside said liquid (7) according to an effect of self-mixing interferometry,
- characterised in that it comprises the steps of:
- detecting, through a first photodiode (9) arranged downstream of said transparent conduit (5), the power of said laser light beam (30) modulated due to said retro-reflection;
- processing said detected modulated power, through a processing and control unit (11), in order to obtain one or more of the following properties of said liquid (7):
- average flowing speed of said liquid (7) in said conduit (5),
- flow rate of said liquid (7) in said conduit (5);
- presence of said suspended particles in said liquid (7),
- average size of said suspended particles in said liquid (7),
- average number of said suspended particles in a volume of said liquid (7)
- type of said suspended particles in said liquid (7).
Apparatus for measuring the properties of a liquid comprising:
- a semiconductor laser source (3) comprising a laser cavity (32) and adapted to generate a laser light beam (30) directed towards a conduit (5) transparent to said laser light beam (30) through which a liquid (7) flows, inside said transparent conduit (5) the power of said laser light beam (30) being modulated due to retro-reflection of said laser light beam (30) towards said laser cavity (32) operated by suspended particles moving inside said liquid (7), according to a self-mixing interferometry effect,
- characterised in that it comprises:
- a first photodiode (9) arranged downstream of said transparent conduit (5), adapted to detect the power of said laser light beam (30) modulated due to said retro-reflection;
- a processing and control unit (11) adapted to process said modulated power detected in order to obtain one or more of the following properties of said liquid (7):
- average flowing speed of said liquid (7) in said conduit (5),
- flow rate of said liquid (7) in said conduit (5);
- presence of said suspended particles in said liquid (7),
- average size of said suspended particles in said liquid (7),
- average number of said suspended particles in a volume of said liquid (7)
- type of said suspended particles in said liquid (7).
Dependencies are inferred from the claim text.