GB575210A - Improvements relating to the production of metal in the form of powder or granules - Google Patents

Abstract

575,210. Freezing spray. KING, D. S. March 6, 1944, Nos. 4132 and 19826. [Class 29] [Also in Groups II and III] In the production of materials in powdered or granular form, the molten material is projected by centrifugal force through apertures in the wall of a rotary drum between turns of one or more electrical heating elements wound round or embedded in the drum and serving to maintain the wall of the drum at a temperature high enough to prevent clogging of the apertures by premature solidification of the molten material. The material is fed into the drum at such a rate that it forms a thin layer on the inside of the drum. The rotary drum 1 is carried by the flange 2 on the end of a shaft 3 carried in bearings 5 in a frame 6 mounted to run on wheels on rails 7 and carrying a motor 8 connected by a flexible coupling 9 to the shaft 3, and supplied with current from a junction box 10 connected by a cable 11 to a control panel 12. The drum is made of ceramic material and is provided with a central opening 14, apertures 15 in its cylindrical surface between the turns of a helical groove 16 in which a resistance winding 17 is laid, the ends of the winding being taken to slip rings 18, 19 with which the brushes 20, 21 contact. The frame 6 is moved forward until the drum 1 lies centrally inside a casing 24 having an opening 25 at the bottom leading to a water tank 26 and also a perforated pipe 27. In operation the water is supplied to the pipe 27 and when the water is running down both sides of the drum 24 the frame 6 is moved into the drum and molten material fed into the latter bv the pipe 28. At the same time the motor 8 is started up and the local heat generated prevents the clogging of the apertures 15. The particles projected through the apertures strike the curtain of water produced in the casing 24 and the solid particles are carried down into the tank 26 where they are removed by an endless conveyor 29. In a modification, Fig. 5, the drum is made in two parts 45, 46 formed with flanges secured together by bolts 47, the apertures consisting of narrow slits separated from one another by the bolts, the width of the slits being fixed by spacing discs 49 of ceramic or like material. The windings 51 in the part 45 is supplied with current by rings 52 and the winding 54 on the part 46 by rings 55. The drum in either form may be mounted so as to be vertical, in a tank provided with a spray pipe similar to the pipe 27. The production of powders or granules of metal or of the materials commonly known as plastics or organic materials such as waxes or resins are referred to.