摘要 |
The device uses the Doppler effect principle of laser velocity measurement. It comprises optical emission and reception guides formed by optical integration techniques on a single substrate (12), preferably glass. The emission guides, connected to a light source (3) produce two mutually coherent beams (1, 2) whose inclination from one another (A) is such as to constitute interference fringes in a measurement region (P) external to the substrate. The reception guides transmit to a detection and processing circuit (11, 9) the light refracted by the passage of particles across the measurement region. The substrate (12) is mounted on a support (15) installed in the orifice of a wall (16) along which flows the fluid transporting the particles to be examined. The substrate (12) comprises a plane (17) that is in contact with the fluid. This device facilitates determining the speed, size and/or number of moving particles in a fluid being displaced along a wall (16).
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