Showing papers on "Jet mill published in 1984"

Fluidized bed jet mill

Abstract: The apparatus disclosed relates to a fluidized bed jet mill having a grinding chamber which is free of fixtures which is provided in its bottom region with a nozzle with a gas jet emerging vertically upward. The jet mill is configured such that when the grinding chamber is filled with the material to be reduced in size, material and gas emerge from the bed of material as a column of little speed. The column serves as a feeder for a classifier provided above the surface of the material bed and driven independently from the impulse of the jet emerging from the bottom nozzle. For improving the efficiency of energy utilization in grinding, a plurality of additional nozzles are provided. The additional nozzles discharge below the surface of the bed of material and into the grinding chamber. The orifices of the additional nozzles are uniformly distributed in a plane running perpendicular to the axis of the bottom nozzle. The additional nozzles are distributed about the circumference of a circle within the plane and coaxial with the axis of the bottom nozzle. The axes of the additional nozzles all intersect at a point on the axis of the bottom nozzle below the plane of the nozzle orifices.

Manufacture of permanent magnet

Abstract: PURPOSE:To produce a thin shaped magnet with good yield by a method wherein rare earth-Fe-B system alloy is refined and powdered, that is, fine grinding is performed after rough grinding, the material is subjected to compression forming in magnetic field and hot extruction process is performed after canning. CONSTITUTION:An ingot, which is the refined alloy of composition showed by the formula, is subjected to rough grinding by stamping mill and jet mill, then is subjected to fine grinding by jet mill. Thereafter, the said powder is subjected to compression forming in magnet field and canning is performed to a forming body using a can made by iron. In this formula, R means Nd only or combination of Nd and one or more than 2 of the othe rare earth element, and M means combination of one or more than 2 of Al, V, P, W, Ti, Ni, Nb, Cr, Mo, Si, Zr, Hf, Mn, Bi, and Sn and Sb. 0<=X<=0.5, 0.02<=Y<=0.3, 0<=Z<=0.03, 4<=A<=7.5. Consequently, hot extrusion process is performed at within the temperature of 600- 1,150 deg.C and extrusion ratio of 3-20. Thus, a thin shaped magnet can be produced with good yield.

Opposed type jet mill

Abstract: An opposed type jet mill, in which a discharge pipe for feeding a mixture flow of high speed gas and ground material discharged from a grinding chamber to an airflow classifying chamber is provided nearly at an equal distance from a new raw material accelerating injector and a regrinding raw material accelerating injector disposed on the left and right hands, respectively, of the grinding chamber and at right angles to a common center line of the both injectors, and a coarse grain return pipe for feeding coarse grains separated in said airflow classifying chamber to the regrinding raw material accelerating injector is disposed so that the angle formed between said return pipe and said regrinding raw material accelerating injector may become an acute angle of 60 degrees or less, which jet mill can reduce energy loss of gas flows and yet can achieve micro-fine grinding.

Fluidised bed-opposed jet mill

Abstract: The apparatus disclosed relates to a fluidized bed jet mill having a grinding chamber which is free of fixtures which is provided in its bottom region with a nozzle with a gas jet emerging vertically upward The jet mill is configured such that when the grinding chamber is filled with the material to be reduced in size, material and gas emerge from the bed of material as a column of little speed The column serves as a feeder for a classifier provided above the surface of the material bed and driven independently from the impulse of the jet emerging from the bottom nozzle For improving the efficiency of energy utilization in grinding, a plurality of additional nozzles are provided The additional nozzles discharge below the surface of the bed of material and into the grinding chamber The orifices of the additional nozzles are uniformly distributed in a plane running perpendicular to the axis of the bottom nozzle The additional nozzles are distributed about the circumference of a circle within the plane and coaxial with the axis of the bottom nozzle The axes of the additional nozzles all intersect at a point on the axis of the bottom nozzle below the plane of the nozzle orifices

Fluidised bed-counter jet mill

Abstract: The invention relates to a fluidized bed jet mill with a grinding chamber free of internals, in the bottom region of which a nozzle with a gas jet emerging vertically upward is arranged. The grinding chamber is completely filled up to such a height with the material to be shredded that material and gas emerge from the bed as low-speed fountains, these fountains being provided for feeding one above the surface of the bed, regardless of the impulse from the floor nozzle escaping jet operated sifter is used. In order to improve the energy utilization during grinding, a number of further jet nozzles are arranged, which open below the surface of the material bed into the grinding chamber and whose openings are evenly distributed in a plane running perpendicular to the axis of the floor nozzle on a circle coaxial to this axis, their axes intersect at a point on the axis of the floor nozzle below the plane of the nozzle orifices.

Effects of feed particle shapes on jet pulverization.

Abstract: On etudie les effets de la forme des particules sur la distribution granulometrique et l'aire specifique du produit, particulierement pour des particules de moins de 10 μm, a l'aide de particules de verre et de quartz de diverses formes