Patent GB-944376-A (GB)
Title: Improvements in or relating to apparatus and a process for moving material
IPC: B01D45/12
Filed: 1959-12-31
Abstract: 944,376. Pneumatic conveyers. SIEMENS-SCHUCKERTWERKE A.G. Dec. 31, 1959 [Dec. 31, 1958], No. 39874/59. Addition to 933,225. Heading B8A. [Also in Division B2] In an apparatus for conveying dust and comprising a duct 1, Fig. 1, and a set of vanes 3, Fig. 2, rotatably mounted about the axis of the duct, reduction of pressure in the duct below the level of the pressure existing at that side of the vanes remote from the axis of the duct induces a flow 6 of fluid medium, e.g. air, towards the axis, the shape and disposition of the vanes 3 being such that upon rotation they impart to the flow a spiral form comprising outer and inner portions respectively of logarithmic and arithmetic form whereby dust, dispersed in the fluid medium or, as shown, disposed as at 5 on the side of the vanes remote from the mouth of the duct, is conveyed by the spiral flow 18, Fig. 4, or a portion thereof into the duct. The duct may be fixed or rotatable. The air is first drawn through a set of fixed straight vanes 4 which are disposed tangentially to a logarithmic spiral to assist in the formation of the spiral flow; alternatively, the vanes 4 may have the form of a logarithmic spiral. The vanes 3 rotate in a counter-clockwise direction and are either straight or are provided with curved inward edges. A member 2 spaced from the mouth of the duet has a concave surface which has the effect of retarding the particles of air in that portion of the spiral flow into contact with it thereby increasing the pressure in that region and giving additional acceleration to the particles of dust in an upward direction. In Fig. 6, rotor vanes 22 are secured to a conical member 21 rotatable about a vertical axis over a member 23. A dust-conveying spiral 26 is formed in the duct 25 and dust which lies or trickles on the member 21 is conveyed by its inclination to fall between the vanes. Additional air is injected through a nozzle 27 to assist in the formation of the logarithmic spiral flow. To convey the dust from the duct 1 or 25, the spiral flow is maintained or re-initiated by a conveying apparatus, Fig. 7, comprising a duct 30 communicating with the duct 1 or 25 and followed by a rotatable duct 31 around the inner surface of which are disposed vanes 38 through which compressed air is injected while suction is created in the duct. In another arrangement, the spiral flow is maintained in a vertically disposed duct in the form of a bend and from the inner surface of which are spaced rotatable vanes. In a further arrangement, the dustladen spiral flow of air passes through curved vanes in a nozzle which is surrounded by further vanes through which compressed air is injected. In Fig. 14, the dust transporting spiral is maintained in a duct 93 by a vortex tube of air entering the duct tangentially and obliquely and produced by air which is caused to flow in a bent duct 95 around a sharp edge 96 and rotatable vanes 97. In a modification, Fig. 15, the vortex tube or air 103 is produced in a nozzle 101 in which the air is acted upon by rotating vanes 98, 99 and asperities 102, 104. The dust-laden air from the conveying arrangements may be directed to a centrifugal separator (see Division B2).