GB877917A - Method and apparatus for pulverizing and/or decomposing solid or molten materials - Google Patents

Abstract

877,917. Pulverizing apparatus. KOHISWA JERNVERKS A. B. Jan. 15, 1959 [Jan. 17, 1958], No. 1538/59. Class 59 A method of pulverizing or disintegrating solid materials or molten materials which are solid at normal temperatures is characterized in that the material is subjected to shock waves travelling at supersonic speed with a movable wave front and with ultrasonic frequency above 20,000 vibrations per second, the shock waves being directed to converge, or be concentrated, on a point or small spot or zone on the material. The frequency of the shock waves is preferably between 40,000 and 100,000 vibrations per second. The shock waves are preferably generated in an inert or reducing gas or in a preheated gas such as air. A device for -carrying out the method comprises an electrically-heated crucible 1, Fig. 1, for melting a metal 3 e.g. zinc or lead, the crucible having a hole in the bottom thereof through which flows a jet 5 of molten metal which falls into the central channel 6 of a shock wave generator 7. The pulverized material is collected in a container 7a. The shock wave generator, Fig. 2, comprises an annular row of cavities 13 on each -side of which are resonance chambers formed by cavities 14, 16 and 15, 17. A gap 18 extends to the central chamber 6. Coaxially with each cavity 13 is a jet hole 19 which connects with a presure chamber 20 to which gas at supersonic speed is suppled through a pipe 21. Shock waves formed in the gap 18 are partially deviated by the walls of the cavities 14, 16 and are directed towards the centre line of the channel 6 in the form of a cone the apex of which is directed downwardly and pendulates axially along the centre line of the channel 6. In a modification, Fig. 3, compressed gas is supplied through one or more pipes 24 to the chamber 23 of an annular element 22 and flows out through holes 25 towards a rotating body 26 having holes 27. A rod 28 of metal or other solid material is fed into a central channel 29 in the body 26. Shock waves are produced which are concentrated on the rod 28 to pulverize it. In another modification, compressed air may be blown through an annualr slit against an edge of a toroidshaped resonator chamber opposite to which is another toroid-shaped resonator chamber. These chambers also act as reflectors and in the gap between them are produced shock waves which are concentrated on a small spot of the solid material. The shock waves may be generated electrically or magnetically.