JMX type jet mill

JMX type jet mill

Jet mill – precision, efficiency, convenience

From the moment we started work on our jet mill, we had an ambitious goal in mind. We wanted to create a device that responds to the most important challenges related to the production of high-quality materials. We were particularly interested in launching a mill that would be perfect for the production of friction materials and grinding processes requiring high purity.

The jet mill offered by Comex is characterized by low energy requirements. Thanks to the use of the highest quality components for its production, the mill is characterized by a low degree of wear of parts. The combination of the grinding chamber with the ACX classifier guarantees high precision of the process and significantly contributes to improving its productivity. The mill gives the possibility of changing the shape of the grain composition curve and allows the production of fine grain up to 2 microns (at d97).

How does the Comex jet mill work?

The principle of jet milling in a dynamic slurry is illustrated in the figure below. It shows a stream of compressed air entering the grinding chamber and accelerating the particles.

The initial velocities of the particles are very small. After acceleration, they reach supersonic speed in the axis of the chamber. Optimum optimal conditions occur when the air pressure in the nozzle area is both high enough to entrain enough particles and not too high so that the amount of mass does not inhibit the stream velocity. The highest speed of the maximum number of particles at the point of collision determines the optimal productivity of the mill.

The feed material enters the mill by gravity through the diagonal inlet pipe (feed). As a consequence, the particles fall into the grinding chamber, in which compressed air nozzles are placed alternately. Air nozzles deliver directed, clean compressed air. The grains of the material are subjected to a force accelerating them to high speeds.

The accelerated particles collide in the axis of the chamber and are ground to a small size. The decompression of the air stream lifts the particles to the top of the mill equipped with an aerodynamic size classifier. The fine grains are sucked out of the device, while the coarse fraction falls into the grinding chamber for reprocessing. The fine grains flow with the air between the impeller blades and then are ejected through the spiral outlet together with the main stream (product). They are separated from the air by means of a cyclone or filter.

Jet mill parameters

Taking into account the market needs for the production of high-grade materials, Comex engineers have created three models of the jet mill. In the table below, we have detailed the exact technical specification of each of the mills available in our offer.

Key benefits:

High precision of nozzles and therefore highly effective particle collision
Ultra-fine and high-efficiency classifier build in the grinding chamber
Low energy requirement when compared to other jet mill types
Fine cut size down to D97=2 microns
Possibilities of changes of the particle size distribution curve shape
Compact mechanical design
Easy inspection and removal of the rotor through the inspection window
Exchangeable blade rotor with quick replacement procedure
Low cost of maintenance for the complete unit
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