In fluid-jet micronizers, the principle of operation is based on the collision of particles of the substance under test. Particles are fed into the grinding chamber through a Venturi injector and are induced to collide along a circular trajectory produced by tangential nozzles placed on the perimeter of the chamber, until kinetic energy drops and motion slows down dramatically. In fact, the particles are dragged by the fluid at very high speed and, as they collide with each other, undergo changes in speed and direction due to the shape of the chamber. In this way, their size is reduced to preset values by the operating conditions of the process. The end result is a granularity that can be smaller than 5 µm.
