Particle Size Reduction - Air Micronisers
Air Micronisers - or Jet Mills - are applied to the superfine grinding of a wide range of specialist materials where other forms of grinders are unsuitable, particularly in cases where the feed material is already relatively fine and where high purity products, without contamination, are required.
British Rema offer 3 types of jet mill, each with their own specific characteristics
• Spiral Flow Jet Mills are appropriate for grinding softer materials producing products generally in the range of 1 to 20 microns and containing significant quantities of ultrafine particles. The principal applications lie in the field of pharmaceuticals and allied products as well as speciality chemicals where sterile and contamination-free operation is essential.
• Opposed Jet Mills are appropriate for the superfine size reduction of a wide range of both soft and hard materials providing product sizes typically in the range of 1 to 80 microns. Combining the principles of Opposed Jet Fluid Energy Milling with the well proven high performance Aerosplit Classifier within a single unit, enables accurate and controllable product sizes to be achieved with sharp cut off and a typically narrow size distribution.
• AJ100 Aerojet Mill/ Minisplit Classifier is supplied as a complete package system suitable for research, development or small scale production purposes. The system incorporates feeder, microniser, product collection system, induced draught fan and integrated control system.
Particle Size Reduction - Air Micronisers, Spiral Flow Jet Mill
Features
• Products range from 1 - 20 microns with wide size distribution
• Low operating temperatures enable heat sensitive and low melting point materials to be processed
• Suitable for sterile operations
• Contamination-free processing
• Coating and blending during grinding operation
• Simple construction allows easy clean down
• No moving parts
• Alternative top or bottom discharge arrangement
• Manufactured in mild steel or stainless steel
• Replaceable internal jet rings and liners in PTFE, ceramics or other specialised material
Operating Principals
• Compressed air is discharged into the shallow cylindrical grinding chamber from nozzles regularly spaced around the chamber (1).
• Air emerges in the form of high energy jets generating a high speed free vortex within the grinding chamber
• Material is fed into the grinding chamber through a Venturi feeder (2) and is introduced by aid of compressed air (3) into the vortex formed by the air jets
• High velocity gradients are set up on the particles within the vortex at the periphery of the chamber resulting in intense impact / attrition grinding
• The free vortex directed inwardly towards the centre outlet results in classification of the material
• Fine particles below the vortex cut size are drawn to the central discharge for collection in the external product collection system (4)
• Particles above cut size are retained in the grinding area until size reduction is complete.
