GB1156520A - Scatter Type Sifters - Google Patents

Abstract

1,156,520. Pneumatic separators. ESCHER WYSS A.G. 6 Sept., 1966 [13 Sept., 1965: 9 June, 1966 (2)], No. 39858/66. Heading B2H. A scatter type sifter for separating a mixture of coarse and fine particles of material, such as cement, comprises a scatter space 17 enclosed by an inner housing 3 and containing a scatter plate 12, a selector blade wheel 15 arranged above the scatter plate, a separating chamber 18 surrounding the scatter space 17, enclosed externally by an outer housing 1 and connected by a channel 21 to the lower region of the scatter space 17, a fan wheel with blades 16 situated in an annular zone 19 connecting the scatter space 17 to the separating chamber 18, and a ring of guide blades 26 arranged below the selector blade wheel 15, each guide blade being pivotable about an axis substantially radial to the sifter axis in order to regulate the degree of fineness of the separated fine particles. The guide blades 26 are secured to pivots 27 which, as shown, project into the separating chamber 18 and are each connected to a lever 30 to which is fixed a ball 31 which is guided in a slot 32 of an adjusting ring 33 which can be rotated from outside the sifter by means not shown to pivot the guide blades. The parts 30, 31, 33 are protected from dust by a hood 39, which is connected by a pipe 41 to a source of filtered compressed air. Alternatively, the pivots 27 may extend to the outside of the wall of the housing 1. Each pivot may be associated with a servomotor, all the servomotors being operable in synchronism by means of a common control device. A disc 14' limits the extent of the scattering jet upwardly and carries on its outer edge a conical guide wall 14" which is spaced from the correspondingly shaped inner end faces of the guide blades 26. In an alternative construction, the guide blades miay be arranged directly under the scatter plate 12. Additional regulation of the degree of fineness is provided by means of slides 35 adjustable by rods 36. The channels 21 are provided with adjustable guide plates 20 which direct the air current, freed from the fine particles in the separating chamber, upwardly into the scatter space 17.