GB187381A - Method of and apparatus for separating fine material - Google Patents

Abstract

187,381. Roth, G. Aug. 15, 1921. Pneumatic separating.-Pneumatic separating apparatus consists of a number of concentric receivers extending one within another, with spreading plates and a centrifugal blower at the lower end of the receiver supplying air for separating purposes, the separation being effected in several separate currents of which the main current is blown through the material while a weaker current is blown through, or induced currents are drawn through the coarse material already treated by the main current. As shown in Fig. 1, the apparatus consists of a number of concentric chambers formed by casings a, b, x, c, d, the inner one a being formed as a cone shaped hopper a<1> at the top having a flange a <2> extending downwardly into the outer chamber. A tube a<3>, to the bottom of which is attached a blower e, is provided with side plates i and a spreader plate f and is fixed to the shaft g by means of which it is rotated. The material is fed by the tube k on to the plates i which distribute it over the surface of the spreader plate f, the plate f spreading the material out as a horizontal layer in the space A between the casings c, x. Air is drawn down the tube a<3> to the blower e, the main current of air issuing at e<2> through a sieve, and passing through the material, a weaker current issuing at e<1> and carrying to the main current any fine material not already separated out. The coarse material drops out at the opening m while the fine material is carried past plates n which separate out any coarse particles mixed with the fine material. The fine material drops between the casings c, d, and is collected at o, the air passing down the hopper a<1> to the blower e. Parts q are turned up on the sides of the hopper a<1> to deflect any fine material carried over into the hopper through openings w into the space between the casings b, x from which it is removed by means of a sloping bottom j and doors y, z<1>, z<2>. In the arrangement shown in Fig. 2, the space A is closed at the bottom by a plate r and dished portion s with a space v between. Blades t are formed on the underside of the blower e and produce an auxiliary current of air. Induced currents pass from a chamber B to the space A through the spaces between the blower e and casings s, v and assist the separating action in a similar manner to that described for the weaker current in the arrangement shown in Fig. 1.