Malvern particle size measurements in media with time varying index of refraction gradients

The capability of the Malvern spray analyzer is extended to include particle size measurements in systems containing time varying index of refraction gradients. This is accomplished by adding conditional sampling optical hardware and electronic circuitry to determine when the Malvern laser beam is aligned and to allow particle size data to be collected only when alignment occurs. The accuracy of the extended instrument is demonstrated by comparing particle size distribution measurements made in the presence of time varying index of refraction gradients with measurements made under static conditions. The limitations of the extended instrument are also discussed.