| 摘要 |
PURPOSE:To increase the quantity of detection light and to enhance S/N so that the flow rate of fluid contg. fine particles flowing in a pipe can be measured with high accuracy by projecting laser light to the above-mentioned fluid and positively detecting the boiling movement of image plane speckles. CONSTITUTION:The laser beam 2 emitted from a laser light source 1 irradiates the fluid in a glass tube 5 converged by a lens 4. The fine particles of a relatively high concn. to be measured are incorporated into the fluid. A flow cell 18 consisting of thin transparent glass plates 18a, 18b is provided and water is filled therein in order to decrease the unnecessary light scattered from the wall of the glass tube 5. The light scattered by the fine particles in the fluid in the glass tube 5 is imaged through a lens 7, an aperture 8 and a lens 9 onto the 1st conjugate image plane having an aperture mask 10. Further, the magnified image of the irradiated section is formed through a macroimaging lens 11 and a half mirror 12 onto the 2nd conjugate macroimage plane disposed with an aperture mask 10' and plural detecting port patterns 14. The light transmitted through the aperture patterns 14 is detected by a photodetector 15 and is subjected to the analysis and evaluation of the flow rate in a signal processing circuit 30. |
