Abstract: A "fluid energy" mill comprising a generally arcuate or torroidal housing in which a centrifugally-whirled circulating stream of high pressure gaseous fluid is used as a grinding medium for particulate material having relatively large particle sizes; the mill having a by-pass duct leading from a classification zone where lighter particles are separated from heavier particles to a grinding chamber; the by-pass duct acting as a passage for the heavier particles back to the grinding chamber where they are mixed with newly entering particulate material fed to the grinding chamber; and a passage in the median portion of the by-pass duct connecting with a separator for removing the heaviest particles from the by-pass duct.

Abstract: A centrifugal type drying mill for wet particles in which hot gases are propelled into the mill to entrain and disperse the wet particles and carry them through an arcuate centrifugal path wherein the lighter, drier particles are centrifugally separated from the heavier, wetter particles and centripetally exhausted from the mill, the mill being formed of square or rectangular cross-sectional shape throughout the major portion thereof, with the inlet or drying chamber being of trapezoidal cross-sectional shape, with the narrower wall thereof at the bottom wherein gaseous inlet nozzles are located, the gaseous inlet nozzles being of rectangular shape to extend across the width of the inlet chamber and being provided with valve means therein to permit adjustment of the angles of entry of the gases into the inlet chamber.

Abstract: A centrifugal drying mill for wet particles comprising an arcuate housing that includes an inlet chamber having a feed inlet and nozzles for propelling hot gaseous fluid into the inlet chamber to dry and propel the fed particles in a centrifugal path through the housing, there being means to concentrate dry particles of varying sizes in the inner portion of the centrifugal path from which they may be centrifugally exhausted from the mill, such means comprising either a baffle plate in opposed relationship to the exhaust means or a rectangular housing section at the area of the exhaust means.

Abstract: A centrifugal drying mill for wet particles comprising an inlet chamber, an upstack leading from one end of the inlet chamber, a classification section connected to the upstack and a downstack leading from the classification section to the opposite end of the inlet chamber to form a generally arcuate centrifugal path, and an exhaust port between the classification section and downstack. The inlet chamber which has tangential nozzles leading into it from a source of hot gaseous fluid is enlarged relative to the remainder of the mill to effect a deceleration and circulation of the incoming particles in the inlet chamber simultaneously with movement of the circulating mass through the inlet chamber toward the upstack.