Sympatec laser measuring device

Heuer and Schweehten [15] designed a sampler for installation with a fluidized bed jet mill where the entire classifier product passed through a Sympatec laser measuring device. This system is suitable for use with... 

Laser diffraction is a fast alternative for analysis of the size distribution of particles in an aerosol cloud. The theory of laser diffraction is well understood [124,125]) but this technique requires special measures to test inhalation devices and to interpret the results correctly. One of the major problems is that flow adjustment through the inhaler is not possible. Furthermore, the presence of carrier particles from adhesive mixtures may disturb the measurement of the fine drug particles and the size distribution obtained is of an unknown dehvered mass fraction of the dose. These practical problems and limitations have been solved by the design of a new modular inhaler adapter for the Sympatec laser diffraction apparatus (Figure 3.6). 

Characteristics of the spray are measured by laser diffraction and analyzed with Fraunhofer diffraction equation, so that the optical properties of the spray are not necessary for the analysis. The device is called HELOS by Sympatec with a measuring range from 0.5 to 175 pm at that lens configuration. The analysis of the diffraction patterns of several drops with different size is mathematically complex and done by the Software of Sympatec, WINDOX . Thus a cumulative volume distribution of the spray, or drop size distribution (DSD), is measured. 

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See also in sourсe #XX -- [ ]

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