Abstract: A jet-type grinding system for grinding relatively large particles, such as coal and the like, wherein the particles to be ground are entrained in a circulating gaseous vortex in which the particles are caused to pulverize each other, the system including a mill having a grinding chamber succeeded by a classifier section in which smaller ground particles are initially separated from larger ground particles, this classifier section constituting a primary separator, the primary separator being in operative connection with a secondary separator into which ground particles pass from the first separator for additional classification and separation into smaller and larger particles, and a tertiary separator inoperative connection wtih the secondary separator to provide passage from the secondary to the tertiary separator of ground particles for additional classification and separation of smaller from larger particles, the passage of all of the particles from one separator to the other being by centrifugal force, an

Abstract: A jet-type grinding mill wherein particles are entrained in a circulating gaseous vortex and caused to pulverize each other during their passage through the mill, the mill having a classifier or separator section wherein there are a pair of coaxial tubular nozzles, one within and radially spaced from the other, the two nozzles forming an auxiliary cyclone-type separator means whereby the lightest of the ground particles pass through the inner nozzle as final product while the heavier ground particles are recycled back for further processing.

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 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.

Abstract: A system for making black powder comprising a jet mill into which potassium nitrate, carbon and sulfur, plus any other desired additive, are inserted, the particles being mixed, pulverized and ground in a vortex of gaseous fluid while the vortex is moved through a curvilinear path in the mill, the smaller, lighter particles being centrifugally separated from the larger heavier particles and then exhausted from the mill, the mill being constructed to decelerate the particles during initial mixture and to thereafter accelerate them through the curvilinear path, the system also including a second jet mill into which are introduced the particles exhausted from the first mill plus an additional coating material, the entire mixture being caused to tumble and roll slowly in the second mill to effect improved smoothing and coating.