What is a spiral jet mill?
Spiral jet mills are often used in the pharmaceutical industry and for the production of fine chemicals. The spiral jet mill from Ebbecke Verfahrenstechnik AG in Bruchköbel works in a relatively simple way: the grinding air is blown in tangentially at the nozzle ring via Laval nozzles. This creates the spiral flow in the grinding chamber from which the mill takes its name. The spiral flow builds up high pressure in the mill. The attached injector, which is powered by compressed air, ensures that the ground material is fed into the machine against the excess pressure. The ground material circles near the nozzle ring and is repeatedly caught by the air jets.
Shredding is achieved by particle-particle impacts due to different particle velocities in the nozzle jet. Crushed material is drawn to the outlet orifice with the air. The particles are subject to a visual effect due to the spiral movement: only fine particles are discharged, coarse particles remain in the grinder.
The features of a spiral jet mill at a glance:
- Vertical grinder housing for easy handling
- Special grinding chamber geometry for grain-free products
- Grinding chamber without rotating internals
- Material feed via injector
- Replaceable nozzle ring
Spiral jet mills are mainly used for high-quality pharmaceutical substances, e.g. antibiotics or fine chemicals, where high demands are placed on the purity and fineness of the products.