Fluid-energy mill

#Fluid energy mills incorporating a vortex propelled by supersonic jet nozzles, referred to as a Micronizer™, are used to reduce the particle size of materials by particle-on-particle impact without the use of moving parts. The mill generally has a grinding chamber with nozzles arranged peripherally tangent to an imaginary circle within the grinding chamber. Compressed gas such as air, steam, nitrogen, etc. is introduced through the nozzles and creates a swirling vortex of gas which travels at high speed around the chamber, at decreasing radii, until the gas exits at an outlet located at the center of the grinding chamber. Feed material is introduced to the grinding chamber as far outside of the grinding nozzle tangent circle as possible to maximize grinding time. The material becomes entrained in the vortex where the rotation generates high-speed particle-on-particle collisions and collisions with the grinding chamber walls creating increasingly smaller particles. Heavier particles stay in the vortex the longest, held there by centrifugal force, until they are light enough to move with the vortex around the chamber and exit with the stream at the outlet. Such mills are capable of producing particle sizes down to the sub-micron range without the introduction of heat common to other forms of particle size reduction.

#According to the invention, a fluid-energy mill includes a one-piece manifold defining a grinding chamber, a gas inlet, a feed inlet, and a feed outlet.

#Embodiments of this aspect of the invention may include one or more of the following features.

#FIG. 1 is a diagrammatic representation of a fluid-energy mill according to the invention;

#FIG. 2 is a rear perspective view of the fluid-energy mill;

#FIG. 3 shows the fluid-energy mill with a cover of the mill opened;

#Referring to FIGS. 1 and 2, a fluid-energy mill 10 includes a manifold 12 and a cover 14. Cover 14 is removably attached to manifold 12 with four sets of thumb screws 16. Manifold 12 defines one or more gas inlet nozzles 18 for the introduction of compressed gas into the mill to create a vortex inside the mill. Manifold 12 includes a particle feed 20 defining a funnel 22 for the introduction of particles to the mill. Coupled to feed 20 is a gas nozzle 24 used to introduce compressed gas into feed 20 to propel the particles into mill 10. Mill 10 can be stabilized on a stand 30 by clamp 32 using a thumb screw 34.

#Referring to FIG. 3, manifold 12 defines a cycloid-shaped grinding chamber 40 with a feed pocket 42. At the center of chamber 40, manifold 12 defines a particle outlet tube 46 and an opening 44 leading to tube 46. Particles from funnel 22 enter chamber 40 at feed pocket 42, are entrained in the vortex where the rotation generates high-speed particle-on-particle collisions and collisions with the grinding chamber walls creating increasingly smaller particles. The particles travel around chamber 40 at decreasing radii, and exit the chamber at outlet 44.

#Manifold 12 has a front face 50 defining a non-circular groove 52 around grinding chamber 40 in which an o-ring seal 54 (FIG. 7) is received. When cover 14 is attached to manifold 12, the o-ring acts to seal chamber 40. In addition, a tensile force is created in thumbscrews 16 by the compression of the o-ring elastomer that limits loosening of thumbscrews 16 during operation.