Appliance for the decantation and recovery of powdery products in pneumatic conveyors

Abstract: Appliance to decant and recover powdery products in pneumatic conveyors, where air is tangentially driven (20) into an annular passage (14) inside a body (10), where it is subject to an expansion and cyclonic motion causing the separation of the product and which it leaves through a conduit and an outlet pipe (19), while the separated product is collected in a conical bottom part (11) of said body for its recovery.

Description: This invention relates to a cyclone allowing the decantation and also a selective recovery of powdery products in pneumatic conveyors. In the document GB-A-960342 a selector in the form of a cyclone is disclosed, and constitutes the preamble of claim 1, for the separation of powdery products or solid particles held in suspension in a gaseous fluid, e.g. air. Such a selector essentially comprises: a cylindrical body with a tapered bottom hopper-like part, a liner concentrically positioned within the cylindrical body for delimiting with said body a first annular passage closed an top and open downward, an inlet conduit to supply the air to be treated in the cylindrical body, at least one port to supply an additional rising-air flow in said cylindrical body, and a vertically movable flow regulator. But, in this known arrangement the inlet conduit for the air to be treated is located above said liner and first annular passage, at the level of an inner wall provided in a fore-body which forms an upward extension of the cylindrical body and defines an outlet passage for treated air. On the other hand, the port for additional air is located at the height of said first annular passage, and the vertically movable flaw regulator operates concentrically within said liner and it is designed to regulate the additional rising-air flow. This arrangement is rather complicated, it does not allow the control of the air flow to be treated and always compel the presence of a rising-air flow for its operation. It is instead an object of the present invention to provide a more simple and efficient cyclone apparatus to be inserted along a pipeline where an air flow is transporting powders, floury substances and the like in order to ease the decantation and separation of said powdery products before the air passes into a cyclofilterventilator. Another object of the invention is to make available a decanting appliance to be connected with other appliances of the same kind but having different dimensions in order to precipitate powdery products of different consistence and/or properties for a more rational removal of the particles in suspension in the air flow to be treated, through a regulation of this air flow. These purposes are achieved by a cyclone according to the characterizing part of claim 1. One embodiment of this invention will however be described with more details in the following specification referring to the enclosed drawings wherein: Fig. 1 is a partially sectional view of the appliance; and Fig. 2 is a sectional view taken along the line defined by arrows II-II in Fig. 1. The proposed appliance comprises a cylindrical hollow body 10, which may consist of several superimposed and flanged sections, completed by a tapered and hopper like bottom part 11 fitted with a leakproof star type discharge valve 12. Inside body 10 a concentrically fixed liner 13 extending along the top section of said body is delimiting an annular passage 14 enclosed between its outer wall and the inside wall of the body, which is closed on top and open towards the bottom and featuring a variable section. Still inside body 10 and under liner 13 a stationary vessel 15 is mounted. Between the rim of vessel 15 and the liner 13 a passage 16 connects the annular passage 14 with the vessel itself. On the other hand, the outer wall of vessel 15 is detached from body 10 thus enclosing an annular passage 14a communicating with passage 14 between body 10 and liner 13. The bottom 15a of vessel 15 is substantially conical and inside said vessel a concentric flow regulator 17 is delimiting an outlet conduit 18 extending from the rim of said vessel to its bottom. The flow regulator 17 is fitted with a pipe 19 with a preferably flared bottom outlet 19a, while its upper end is extending towards another (not shown) appliance or towards a cyclofilterventilator. The flow regulator 17 with its pipe 19, 19a is vertically adjustable so as to modify the section of the outlet conduit. At the height of liner 13 a conduit 20 is tangentially fitted on body 10, to take the air flow in a tangential direction into the decanting appliance. Its inlet port 21 is however fitted with a gate 22 to be operated either manually or automatically to adjust inlet section and angle of the air flow and its expansion inside the appliance. Finally, a rotating ring 23 or any other suitable means to vary the opening of the lateral ports 24 letting in some more air when it is required and necessary, may be mounted on said cylindrical body 10. In practice, the air transporting the powdery product tangentially enters the top section of the cylindrical body 10 and circulates inside the annular passage 14. The expanxion and cyclonic behaviour of the air inside said passage cause the descent of the heavier particles which thus pass through passage 14a and are collected in the tapered bottom body 11, from where they can be discharged through the star type valve 12. The air itself, passing through channel 16, flows through conduit 18 entraining any product residues or dust eventually deposited in the container to pass, through pipe 19 and by aspiration, into a conventional cyclofilterventilator. The expansion of the entering air may be adjusted, in order to modify the decanting conditions of the product, by means of gate 22, while by vertically adjusting the flow regulator 17 the section of the outlet conduit 18 can by changed according to the product to be recovered. Finally, by acting on ring 23 some additional air may be fed through ports 24, as may be necessary in some cases to increase the quantity of product to take to the cyclofilter or to any following equipment, said air being in any case recovered through a not shown conduit from the dome of the cyclofilter.

Claims: A cyclone for the decantation and recovery of powdery products in pneumatic conveyors, cyclone comprising: a cylindrical body (10) with a tapered bottom hopper-like part (11); a liner (13) concentrically positioned within the cylindrical body (10) for delimiting with said body a first annular passage (14) closed on top and open downward; an inlet conduit (20) to supply the air to be trated in the cylindrical body; at least one port (24) to supply an additional rising-air flow in said cylindrical body; and a vertically movable flow regulator (17); characterized in that a vessel (15) is concentrically mounted in said cylindrical body, below said liner, and has an outer wall detached from said body so as to form a second annular passage (14a) communicating with the first annular passage between said liner (13) and said body and a conical bottom (15a), in that said inlet conduit (20) is tangentially fitted to said cylindrical body (10) at the height of said first annular passage (14), in that said movable flaw regulator (17) is concentrically mounted within said vessel (15) so as to delimit with said vessel an outlet conduit (18) extending from the rim to the conical bottom (15a) of said vessel and communicating with said first annular passage (14) through a passage (16) enclosed between said liner (13) and the rim of said vessel, and in that an air outlet pipe (19) is fixed to said movable flow regulator (17) and is open towards the bottom of vessel (15) and connected with a cyclofilterventilator or any other equipment. The cyclone according to claim 1, wherein said liner (13) is extending along an upper section of said cylindrical body (10), and said first annular passage (14) has a variable cross-section. The cyclone according to claims 1 and 2, wherein said movable flow regulator (17) with said outlet pipe (19) is vertically adjustable in order to very cross-sectional area of said outlet conduit (18). The cyclone according to claims 1 and 2, wherein a manually or automatically operated gate (22) is coordinated to said air inlet conduit (20) to vary the inlet angle and cross-section of air entering the cyclone. The cyclone according to the preceding claims, wherein ports or slots (24) are provided in said cylindrical body for admission of additional air and a movable closing element (23) is provided to open and close said ports or slots. The cyclone according to the preceding claims, wherein air flow entering through inlet conduit (20) is directed to into first annular passage (14) allowing expansion and cyclonic motion promoting the separation of the transported product from the air flow, whereby the air flow then passes to the outlet conduit (18) and the discharge pipe (19) while the separated product is collected in the tapered bottom part (11) to be removed by opening a discharge valve fitted to said tapered bottom part.

Inventors: PIANEGONDA FRANCESCO, PIANEGONDA, FRANCESCO
Applicants: SKYWAY DEV LIMITED, SKYWAY DEVELOPMENT LIMITED
Application year: 1990
Main classification: B04C5
IPC codes: B04C5, B04C11, B65G53