Aerodynamic recirculating bulk material separator

Abstract

An aerodynamic recirculating separator of bulk materials that includes an air blower capable of forming an air stream, an outlet stream directing means, a separation chamber including two inlets and two outlets, a loading hopper, at least one discharge channel, a return air duct including a plurality of turning portions, and at least one residue collection chamber. An outlet of the air blower connects to the first inlet of the separation chamber, an outlet of the loading hopper connects to the second inlet of the separation chamber, the first outlet of the separation chamber connects to the return air duct, and the second outlet of the separation chamber connects to the at least one discharge channel. The air blower, the separation chamber, and the return air duct are consecutively connected so as to form a recirculation channel. The separator forms a material particle flow from the loading hopper to the separation chamber, to distribute commercial particles by their aerodynamic parameters in the separation chamber as the commercial particles fall from the loading hopper and are blown by the air stream formed by the air blower, and to remove the commercial particles through the at least one discharge channel. The separator forces remaining material particles into the at least one horizontally flared portion, directs at least a part of the remaining material particles into a residue collection chamber by way of gravity, and injects air into the separation chamber via the discharge channels. The first downstream horizontally flared portion includes a downwardly curved bottom wall and an opening in communication with said flared portion and the external environment. The opening is disposed in a smooth turn zone from said flared portion to the first of the plurality of turning portions, which has an upward turn.

Claims

1. An aerodynamic recirculating separator of bulk materials, comprising: an air blower capable of forming an air stream and including an outlet stream directing means; a separation chamber including a first inlet, a second inlet, a first outlet and a second outlet; a loading hopper; at least one discharge channel; a return air duct including a plurality of turning portions; and at least one residue collection chamber; wherein an outlet of the air blower is mated to the first inlet of the separation chamber; an outlet of the loading hopper is mated to the second inlet of the separation chamber; the first outlet of the separation chamber is mated to the return air duct; the second outlet of the separation chamber is mated to the at least one discharge channel; the air blower, the separation chamber, and the return air duct are consecutively mated so as to form a recirculation channel; the separator is capable of forming a material particle flow from the loading hopper to the separation chamber, distributing commercial particles by their aerodynamic parameters in the separation chamber as the commercial particles fall from the loading hopper and are blown by the air stream formed by the air blower, and removing the commercial particles through the at least one discharge channel; the return air duct includes at least one horizontally flared portion, in communication with at least one residue collection chamber via an opening in a bottom wall of the return air duct; the separator is capable of forcing remaining material particles into the horizontally flared portion and directing at least a part of the remaining material particles into the at least one residue collection chamber by way of gravity; wherein the separator is capable of injecting air into the separation chamber via the at least one discharge channel; the first downstream horizontally flared portion includes a downwardly curved bottom wall between the beginning of the first downstream horizontally flared portion and the opening of the first downstream horizontally flared portion; the opening of the first downstream horizontally flared portion is disposed in a smooth turn zone from the first downstream horizontally flared portion to the first of the plurality of turning portions, the first of the plurality of turning portions having an upward turn; and the opening of the first downstream horizontally flared portion is the only opening of the return air duct that is in permanent communication with the external environment.

2. The separator of claim 1, wherein the outlet stream directing means is capable of setting a direction having a component directed away from the at least one discharge channel.

3. The separator of claim 1, wherein the outlet stream directing means comprises a louver screen.

4. The separator of claim 1, wherein the opening of the first downstream horizontally flared portion is covered by a plurality of vanes directed opposite to the air stream.

5. The separator of claim 1, further comprising: at least two residue collection chambers; and at least two horizontally flared portions; wherein a second downstream residue collection chamber lies in the zone of a second downstream horizontally flared portion; and the residue collection chambers, with the exception of the first of the at least two residue collection chambers, include a dumping means adapted for temporary opening.

6. The separator of claim 5, wherein the dumping means comprises valves capable of opening under the effect of the weight of the bulk material accumulated in the corresponding residue collection chamber.

7. The separator of claim 1, further comprising: a top air splitter, the top air splitter being disposed at the inlet part of the first downstream horizontally flared portion, at the opposite side from the first downstream residue collection chamber, the top air splitter being directed co-current with the air stream and capable of deflecting the air stream to the inside zone of the first downstream horizontally flared portion; and a bottom air splitter, the bottom air splitter being disposed at the first of the plurality of turning portions, the first of the plurality of turning portions having an upward turn, the bottom air splitter being disposed at the side of an opening into a subsequent downstream residue collection chamber, the bottom air splitter being directed against the air stream, and capable of retarding the air stream at the zone between the splitter and the surface of the air duct.

8. The separator of claim 1, wherein the first of the plurality of turning portions is narrowing upwards.

9. The separator of claim 1, wherein: the at least one discharge channel comprises two pipelines interconnected at their inlets; and the outlets of the pipelines terminate at opposite sides of the separator, and are equipped with gates capable of blocking the outlets.

10. The separator of claim 1, wherein the residue collection chamber in communication with the opening of the first downstream horizontally flared portion comprises a container disposed under the opening.

11. The separator of claim 1, further comprising at least two discharge channels.

12. The separator of claim 11, wherein a last discharge channel of the at least two discharge channels serves to remove pollutant particles that are lighter than commercial particles.

13. The separator of claim 11, wherein a first discharge channel of the at least two discharge channels serves to remove pollutant particles that are heavier than commercial particles.

14. The separator of claim 1, further comprising more than three discharge channels.

15. The separator of claim 1, wherein the air blower comprises an axial fan.

16. The separator of claim 1, wherein a fan rotation frequency controller comprises a frequency converter.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The FIGURE is a schematic depiction of the front view of the aerodynamic recirculating separator of bulk materials according to the invention, with the air duct front wall being removed.

DETAILED DESCRIPTION

(2) The aerodynamic recirculating separator of bulk materials according to the invention, as presented in the FIGURE, comprises the air blower 1 outlined with a dash line and including the drive motor 2, the impeller 3 installed in the tube which together form the axial impeller-type fan, and the stream directing means at the outlet in the form of the louver screen 4, the separation chamber 5 with two inlets and two outlets, the loading hopper 6, three discharge channels 7, the return air duct 8 with a number of turning portions and, finally, the first 9 and the second 10 residue collection chambers. The air blower 1 outlet is mated with the separation chamber 5 first inlet, an outlet of loading hopper 6 is mated to the separation chamber 5 second inlet, the separation chamber 5 first outlet is mated with the return air duct 8, whereas its second outlet is mated with each of the discharge channels 7. Consecutively mated the air blower 1, the separation chamber 5 and the return air duct 8 together form a channel where the air stream circulates (recirculation channel). The return air duct 8 is divided into several portions, their boundaries being defined by projections of planes in the form of dash-dotted lines specified with Latin letters. So, the return air duct 8 comprises at least one horizontally flared portion A-B, which is connected with the first residue collection chamber 9 via the opening 11 in the bottom wall of the air duct 8. To ensure the air stream recirculation flow, the part of the turning portions has turns in the vertical plane. Such portions in the FIGURE are, for instance, portions B-C, C-D, E-F. The separation chamber 5 is capable for the air injection via the discharge channels at the expense of the air stream being directed upwards, away from the discharge channels. The downstream first horizontally flared portion A-B has the downwardly curved bottom wall 12, whereas the opening 11 to the residue collection chamber lies in a smooth turn zone from this portion up to the first of the said turning portions having an upward turn B-C, and it is the only opening in the return air duct 8 which has the permanent communication with the external environment. The opening 11 is covered with several vanes 13 directed opposite to the air stream flow. The opening 14 to the second residue collection chamber 10 is covered by several vanes 15. At the bottom of the second residue collection chamber the dumping means is made as the valve 16. At the inlet part of the first horizontally flared portion A-B at the side opposite to the residue collection chamber 9 the top air splitter 18 is installed directed along the stream flow, whereas at the first turning portion having an upward turn B-C, at the side of opening to the first residue collection chamber 9, directly downstream after this opening the second air splitter 19 is installed which is directed against stream flow.

(3) The device operates as follows. The air blower 1 forms the air stream in the return air duct 8 which central part is depicted in the FIGURE with a heavy dot short-dashed line, the said air stream being directed by the lip screen inclined to the horizontal plane, away from the discharge channels 7. The bulk material to be cleaned and separated comes from the bottom outlet of the loading hopper 6 to the separation chamber 5, where it is blown with the said air stream, so that the heavy particles of the bulk material fall down effected by gravity and, depending on their aerodynamic characteristics, deflect under different angles from the vertical trajectory and correspondingly get to the different discharge channels as different commercial or heavy non-commercial fractions. As the air stream is directed to the opposite side from the discharge channels, the air is injected via the latter to the main air stream, and these streams are depicted with the thin short-dash lines. The velocity of these streams is insufficient to cause the soaring of the heavy particles directed to the discharge channels 7, but it is sufficient to enable soar the light particles entrained by them. In this way the high cleaning degree of the material commercial fractions is attained.

(4) After that the light soaring particles getting to the air stream from both the loading hopper and from the discharge channels get to the horizontally flared portion A-B where the velocity of the stream and, thus, of the particles is so reduced that the most particles stop soaring. As the portion A-B bottom wall 12 is downwardly curved, the adjacent parts of the portions A-B and B-C form the indentation 17 wherein the non-commercial particles fall; they are pushed by the air, change the motion direction from quasi-vertical to quasi-horizontal and partly due to their inertia, as in the cyclone, get under the vanes 13 to the opening 11 and are removed from the air duct to the first residue collection chamber 9. The said indentation 17 with the vanes 13, the opening 11 and the residue collection chamber 9 will be hereinafter described as a cyclone-residue collection chamber.

(5) The top air splitter 18 presses the air stream in the direction of the cyclone-residue collection chamber, whereas the bottom air splitter 19 brakes the air stream at the zone between it and the air duct wall, thus slowing the particles velocity so that they stop soaring and return to the opening 11. The shape and the location of the air splitters 18 and 19 should be selected by the experimental way or calculated so that the conditional border line between the pressurization zone and the exhaustion zone pass nearby, preferably through the splitters. In this case second and downstream subsequent (if any) residue collection chambers would lie just in the exhaustion zone.

(6) The necessary condition for a reduced pollution outcome from the cyclone-residue collection chamber to the environment is a relatively low velocity of the air stream and the particles in the opening 11. Practice shows that said velocity should not exceed 2 m/s, what is quite attainable in the proposed design of the cyclone-residue collection chamber for all kinds of bulk grain materials and the other bulk materials of the similar density.

(7) Then the air stream moves along the turning portion having an upward turn B-C where due to its narrowing stream velocity increases and the particles are injected forced in into the horizontally flared portion C-D. Being effected by the gravity force the non-commercial particles still remaining in this stream fall down under the vanes 15 and get to the second residue collection chamber 10. When the mass of accumulated particles at the second residue collection chamber 10 exceeds the prescribed value, a valve 16 under the pressure of this mass opens downwards, and accumulated particles are removed from the second residue collection chamber, after what the valve 16 quickly closes.

(8) Actually cleaned from the pollution the air stream continues further along the return air duct 8 and arrives in the air blower 1 inlet, and then the cycle is repeated.

(9) If necessary, the additional residue collection chambers may be installed downstream in the return air duct 8, for instance, after the portion D-E.

(10) For the treatment of some special bulk material the downstream first discharge channels 7 may be assigned for the separation of the non-commercial fractions which are heavier than the commercial fractions. In another case the downstream last discharge channels 7 may be assigned for the separation of the non-commercial fractions which are lighter than the commercial fractions but have the soaring velocity substantially higher than the air stream velocity in this zone.

(11) The number of the discharge channels depends on the type of the bulk material to be treated. But to ensure the separator universality their number must be at least three to enable the separation of the commercial fractions by their quality depending on dynamic characteristics of the particles.

(12) Instead of the louver screen 4 the guiding nozzles may be applied as the stream directing means.

(13) The discharge channels serve, particularly, to direct the extracted fractions to their collecting grounds. For this purpose each channel is equipped with two pipelines mated in their inlets (not shown), whereas their outlets end in the opposite parts of the separator and are equipped with the gates capable for closing. Thus, for instance, the commercial fractions may be directed to one side of the separator and the non-commercial fractions to the opposite side. If the separator is fixed, these fractions may be picked up by the corresponding means, for example, the conveyors. In case of movable, e.g., a wheeled separator the fractions may be collected into stacks and then picked up. Preferably the separator according to the invention may be equipped with a discharge conveyor which inlet is mated with the outlets of at least some discharge channels to enable the commercial fractions being collected at the necessary place, e.g. truck body. Such conveyor may be capable for rotation around the vertical axis in its inlet part and/or capable for changing angle of the incline relative to the horizontal plane, thus enabling the loading the commercial fractions to the different heights and in different directions, what substantially increases the universality of the separator according to the invention.

(14) The separator according to the invention may be also equipped with means for supply of the bulk material to the loading hopper, e.g. an inclined conveyor with the horizontal pickup of the bulk material disposed, e.g. on the ground.

(15) The first residue collection chamber 9 may be made as a removable container installed under the opening 11 in the air duct, preferably at the minimum distance from it, but sufficient for unhindered the air outcome therefrom.

(16) The air blower 1 in the form of an axial fan ensures the motor rotation frequency control with a frequency converter (not shown) which would be difficult in case of the centrifugal fan, considering first of all the motor cooling conditions. Such control is necessary in the case of the separator setup according to characteristics of the special bulk material.

(17) Thus, the aerodynamic recirculating separator of the bulk materials have been developed wherein due to described improvements the quality of cleaning of the extracted material fractions is increased, due to the deeper air cleaning within the separator its operational parameters are improved, e.g. service life and time between maintenance checks, separator control is simplified and better conditions appear for the deeper cleaning of the air exhausted to the environment, thus expanding the separator application opportunities.