Patent ID: 7398934

Claim:
A deep-chamber, stepped, fluid-energy mill, for comminuting particulate material, said fluid-energy mill comprising: (a) a cover, comprising a first circular-shaped axial wall; (b) a base, comprising a second circular-shaped axial wall opposing said first circular-shaped axial wall, and a peripheral wall extending from said second circular-shaped axial wall; wherein said first circular-shaped axial wall, said second circular-shaped axial wall, and said peripheral wall define a disc-shaped chamber of a radius R; (c) a multiplicity of inlets extending through said peripheral wall of said base and aligned for directing grinding fluids into said disc-shaped chamber; (d) a feed-inlet integral, attached to said first circular-shaped axial wall of said cover, on the side opposite to that side of said first circular-shaped axial wall of said cover, which forms said disc-shaped chamber, (e) a discharge tube for withdrawing said particulate material and grinding fluid along the axis of said disc-shaped chamber; wherein at least one of said first circular-shaped axial wall and said second circular-shaped axial wall, on their respective sides that form said disc-shaped chamber, have at least one ring-shaped discontinuity concentric to the disc-shaped grinding chamber extending from said first circular-shaped axial wall and/or said second circular-shaped axial wall into said disc-shaped chamber; wherein said at least one ring-shaped discontinuity is located concentrically to said disc-shaped chamber at a distance of from about 0.59 R to about 0.62 R from the axis of said disc-shaped grinding chamber; wherein said disc-shaped chamber is lined with a first ceramic liner; wherein said first ceramic liner extends from the inside of said disc-shaped chamber to the inside of said feed-inlet integral thereby defining the feed-inlet tube; wherein said feed-inlet integral has a packing gland that floats between said feed-inlet tube and said inside wall of said feed-inlet integral; wherein said feed-inlet tube is optionally tapered in the direction opposite of the grinding fluid flow; wherein, optionally, said feed-inlet integral and said cover form a single unit; and wherein said discharge tube is lined with a second ceramic liner and wherein said first ceramic liner and said second ceramic liner form a joint there between, the joint being shaped such that the direction of said grinding fluids and said particulate material, exiting said disc-shaped chamber, is opposite to the direction of said grinding fluids and said particulate material required to impinge and penetrate said joint of said ceramic liner and said second ceramic liner.