Novartis NNM nano sand mill adopts double end face mechanical seal and grinding medium. The material enters the grinding chamber from the top of the feed pump. In the strong grinding process, the rod pin and stator continuously and violently impact the grinding medium. The grinding medium acts on the material again, and the material is fully ground. At the discharge port, due to different density, the grinding medium returns to the grinding chamber, but the material flows out of the grinding chamber through the gap separator under the pressure of the feed pump. The large flow and cyclic operation mode ensures the short residence time of the material in the grinding chamber and passes through for many times, so as to obtain the particle size distribution of nanometer products.