The invention relates to processes for measuring and controlling particle sizes in micro- and nanoemulsions, colloidal solutions and suspensions of particles in liquids and gases. The invention is applicable in chemical processes, in particular, in
petrochemistry, transportation of
petroleum products, oil and gas, in food and medical industries,
medical research, for producing nanoparticles for electronic and electrical industry, controlling the state of operating fluids in mechanical and
power engineering, i.e. for controlling the processes for producing or using colloidal solutions, emulsions and suspensions of
solid or liquid particles.A new method of measuring sizes of particles suspended in a liquid using optical mixing
spectroscopy of
scattered light and an apparatus for implementing the method are disclosed. The method consists in making measurements by a
fiber optic probe introduced into a medium under investigation, the probe comprising several multiple or single mode optical fibers. One of the optical fibers transmits light into the medium, while the other optical fibers transmit
scattered light to a device for providing
spatial coherence of the light and then to a
light detector. Auxiliary optical fibers are used to determine the relationship between
spectral line widths of multiple and single
light scattering when measurements are conducted in very turbid media and for determining particle sizes from multiple rather than single scattering spectrum. The attained technical result is that the method does not require the use of single mode optical fibers and
integrated optics, and placing a suspension sample into an optical
cell as it is common in conventional methods. The method exhibits an enhanced
immunity to interference caused by dust in the sample. Therefore the invented method enables particle size measurements both in laboratory cells and test tubers, and directly in pipelines of production units, barrels, tanks and other reservoirs with finished product, chemical reactors, canisters and trays of
machining tools, etc. The method can be used both invasively and noninvasively, i.e. for studying a medium through a transparent window.