RU2462319C2 - Method of separating loose mix in fluid and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to methods and device for air separation of loose materials and may be used, mainly, in agriculture for grain cleaning and sorting, food, chemical and coal industries, etc. Proposed method consists in gravity feed of separated mix particles, exposing said particles to aerodynamic continuously increasing effects at acute angle to vertical line brought about by multiple flat jets and discharge of finished fractions. Prior to said aerodynamic continuously increasing effects to mix particles, flow of every jet is changed into developed turbulence pattern by expanding said jets in vertical to their merging to feature eagre pattern or that approximating thereto, and by forming two different-size circulation zones, top and bottom zones at the beginning of every jet spacing of all adjacent jets. Prior to forming said circulation zones, jet flow direction is abruptly changed from vertical to, approximately, horizontal with subsequent contraction over vertical. Proposed method is implemented with the help of device made up of bin with vibrating tray, generator arranged there under and having stiff walls located one under another at acute angle to vertical, their spacing and width increasing from top to bottom, and fraction collectors. Said generator is communicated with compressed air feed device and confined by outer walls. End of every stiff wall is provided with additional wall arranged at angle thereto and there under, its width being smaller than distance between adjacent stiff wall above it and airflow deflection chamber at clearance entrance. Deflection chambers and clearances increase from top to bottom.

EFFECT: higher efficiency of separation, simplified design and process.

2 cl, 2 dwg

Description

The invention relates to methods and devices for air separation of bulk materials and can be used mainly in agriculture for cleaning and sorting seeds of cereal, grass and other crops, at breeding stations, in farms, in milling and animal feed production, as well as the production of building materials, in the food, chemical, coal industries for the enrichment of coal and in other sectors of the economy.

The prior art method for the separation of bulk materials, including sequential operations of feeding bulk material into the separation zone, preliminary intensive separation of the specified material in a vertical variable speed air stream into light and heavy particles with the simultaneous release of light impurities and dust from them falling into the sedimentation chamber, equipped with a periodic shutter and a suction fan. The remaining light and heavy particles, being in a vertical stream, gradually move to the bottom, where they fall under the action of an almost horizontal continuous air stream that separates these particles in a horizontal separation chamber into separate fractions that are output to the receivers of the finished fractions. This method is implemented using the known pneumatic separator of bulk materials, containing a horizontal separation chamber equipped with receivers of the finished fractions, and a vertical pipeline of variable cross section attached to it, on top of which is a hopper for the separated material. On the side of the hopper, a precipitation chamber is attached to the vertical pipeline, equipped with a suction fan, in front of which a periodic shutter is installed, kinematically connected with the cam mechanism of its rotation [see A.S. USSR No. 1407587 in class B07B 4/02, published 07/07/1988 in Bull. No. 25].

The main disadvantage of the known method of separation of bulk materials is the high complexity of the separation process and the low quality of separation of the material into separate fractions, which is caused by a pulsating change in the parameters of the vertical air flow in the pipeline and the horizontal air flow in the pneumatic chamber due to the frequency of connection of the precipitation chamber to the suction fan using flaps. When the damper is opened, the pressure of these air flows decreases, which leads to instability of the separation process and worsens the conditions for the separation of the material into fractions. The low quality of the separation process is explained by the fact that at the stage of separation of light and heavy particles in a vertical air flow, a so-called shielding effect occurs, in which heavy particles carry lighter particles along with them and pass through a horizontal air flow in the separation chamber and are inappropriate for them fractional collections. Moreover, the design of the known device is not able to eliminate the influence of this phenomenon, which confirms its imperfection and is its drawback. In addition, the disadvantage of the known pneumatic separator should be considered its high complexity due to the presence of an additional precipitation chamber, which is also equipped with additional devices and a fan, significant overall dimensions, in particular height, due to the inclusion of a vertical pipeline in the design, as well as high energy consumption due to the presence of two fans in the design, which make the separation process rather energy-consuming and, because of this, costly.

There is also known a method of separating bulk materials, including the gravitational flow of bulk material with a given speed into the zone of action of the electric field and the subsequent separation of the particles of material in a uniform counter ascending air flow and removal of separation products. A device for implementing this method comprises a hopper with a feeder, a fan, air ducts and a separation chamber made of a dielectric material in the form of a rectangular vertical pipe equipped with electrodes located on its inner opposite walls, and contains a system of air pipes entering inside it and equipped with diffusing tips and valves to control the speed of the oncoming air flow in the interelectrode space, as well as interconnected by sealed con other collections collecting fractions of the separated material [see US Pat. Russian Federation No. 2262994 for classes B07B 4/02, B03C 7/12, published October 27, 2005 in Bull. No. 30].

The use in a known technical solution of the counter ascending air flow provides a sufficiently thin and high-quality separation of particles of bulk materials. However, the disadvantage of this method is that the formation of this air flow is forced, therefore, is associated with the need to use a complex system of its settings. For high-quality separation, depending on the specific composition of the separated mixture, it is necessary to simultaneously adjust the air flow rate, electric field strength and the amount of particle feed from the hopper. Due to the lack of a single automatic process control system, energy and labor costs for implementing this separation technology are significantly increased. In addition, it should be noted that the function of separating particles in an electric field is absolutely useless, since the particles of the separated mixture are dielectrics. The main disadvantage of the known device is that it has a too complicated design, in which there are a large number of interconnected parts and assemblies, often small and high-tech, as well as the use of two types of energy resources for the separation process (for example, a hopper feeder, a control valve, fan power supply, etc.).

Also known are a method of separating a granular mixture in a fluid medium and a device for its implementation, the essence of which is as follows. A method for separating a granular mixture in a fluid includes a gravitational feed of particles, a monotonically increasing aerodynamic effect on them at an acute angle to the vertical by a cascade of flat jets and removing finished fractions, while the cascade of flat jets is exposed in a free alternating force scanning mode with increasing amplitude and scanning angle . A device for implementing this method comprises a hopper with a vibratory tray, a jet generator mounted underneath with flat nozzles located one below the other and at an acute angle to the vertical, whose cross-sectional height, pitch and installation angle increase from top to bottom, and the generator is connected to the supply source air under pressure and covered by the side walls, and fraction collectors are located under the nozzles [see US Pat. Ukraine №45881 for class B07B 4/02, published April 15, 2002 in Bull. No. 4].

The main disadvantage of the known separation method is the low quality separation of the granular mixture into fractions, especially particles with a significant difference in mass and density. This disadvantage is as follows: alternating and free operation of the cascade of jets inevitably leads to the periodic, unstable in time and space, the appearance of pressure and vacuum zones with the appearance of forward and reverse flows. In the reverse flow zone, particles (especially light ones) are drawn into motion in the opposite direction to the main flow, which leads to partial mixing of the already separated material. The instability in time of this phenomenon, ultimately, leads to the opening (rupture) of the cascade of jets in any random place, which leads to a breakdown of generation, as a result of which the quality of separation is drastically reduced. A disadvantage of the known device is the imperfection of the generator of the cascade of jets, in particular nozzles, the design of which cannot eliminate the appearance of reverse air flows in the separation chamber, which leads to a decrease in the quality of separation.

The closest in their essence and the achieved effect, taken as a prototype, is a method for separating a granular mixture in a fluid medium and a device for its implementation, the process and structural essence of which is as follows. A method for separating a granular mixture in a fluid includes a gravitational feed of particles, a monotonically increasing aerodynamic effect on them at an acute angle to the vertical by a cascade of flat jets and removing the finished fractions, while before each aerodynamic action on the mixture particles, the flow of each jet is transferred to the developed turbulence mode by expanding the jets vertically until they merge with each other with a faulty or close to it form of flow and formation at the beginning of each inter-jet space of all adjacent jets at least the two circulation zones, different in magnitude. A device for implementing the proposed method for separating a granular mixture in a fluid medium contains a hopper with a vibratory tray for gravitational feeding of the mixture into the separation zone, under which a jet generator is installed, with nozzles with rigid walls located one below the other and at an acute angle to the vertical, adjacent to them from above along the entire width, as well as the pitch and width of the nozzle arrangement, increases from top to bottom, and the generator is connected to a source of pressurized air and is surrounded by side walls that simultaneously form separa a baking chamber with fraction collectors located under it. In addition, the width of the rigid wall is at least three sizes of the cross-sectional height of the adjacent nozzle, and the ratio of the nozzle installation step to the cross-sectional height of the upper nozzle relative to it is at least four [see International application No. W02010056220 for classes B07B 11/00, B07B 4/02, B07B 4/00, published on 05/20/2010].

The main disadvantage of the known method of separating a granular mixture in a fluid is its low productivity, predetermined by the insufficient intensity of the separation process. This is due, first of all, to technological limitations regarding the provision of turbulence, namely: only by bilateral expansion of the jets with their subsequent merging into one faulty flow. In this case, it is impossible to stably maintain sufficiently powerful turbulence, since only two circulation zones arise and function (according to the stated proposal, no less than two, but, as practice shows, no more, for confirmation of which see Fig. 1 in indicated international application, where circulation zones are depicted by the author). The lack of technological ability to increase the number of circulation zones without the risk of disrupting the generation and destruction of the faulty form of the jet stream, as well as creating additional aerodynamic effects to enhance the turbulence phenomenon, for example, by creating microvortices, makes it impossible to increase the intensity and quality of the separation process, in particular, increase the layer thickness mixture during its gravitational flow. That is, this scheme of forming a cascade of jets and turbulence zones has exhausted its capabilities, since it does not seem possible to achieve more developed turbulence in the separation chamber, therefore, it is impossible to improve the quality of the process of separating a granular mixture into separate fractions.

The main disadvantage of the known device for separating granular mixture in a fluid is the presence in its design of a flat horizontal nozzle of the generator. It is known that the nozzle, as a technological device, is designed to accelerate liquids or gases to a given speed and give the flow a certain direction. As a result of the use of plane-horizontal nozzles in the design of the known device, the cascade of air jets is too powerful and fast, therefore, the zone of developed turbulence shifts to the middle of the separating chamber and has a short width, therefore, in it the complete separation of the mixture into fractions does not have time to completely occur. Consequently, part of the granular mixture, first near the nozzles, is accelerated by continuous jets to a high speed and then partially slips right through the developed turbulence zone, remaining unseparated - they are simply demolished by powerful air currents, and they randomly settle in different collectors. This leads to uncontrolled formation of mixed fractions. Therefore, the presence of these nozzles with rigid walls in no way contributes to improving the quality of separation, even, on the contrary, worsens and unjustifiably complicates the design of the separator.

Another significant drawback of the known device is that the entire set of nozzles with rigid walls of the generator is located in one vertical plane. Given the fact that rigid walls are installed at an acute angle to the vertical, their pitch and angle increase from top to bottom, “pockets” are formed between the vertical wall of the generator and each of the above rectangular rigid walls, where particles of the granular mixture, heavy impurities, etc. d. Over time, this leads to the filling of these "pockets" with these substances. In view of the perceptible size of such accumulations (the width of the rigid walls increases from top to bottom), it becomes necessary to periodically stop the separator and clean it in order to avoid overloading and worsening conditions for the formation of a cascade of jets. This procedure is inconvenient and quite lengthy, since the device needs to be disassembled, as well as economically unjustified, because the forced "idle time" negatively affects the overall performance of the device. In addition, the design of the nozzles themselves with rigid walls, which are quite difficult to manufacture and fix in parallel in the generator, is generally imperfect.

The proposed invention is aimed at achieving a technical result, which consists in increasing the productivity of the process of air separation of a granular mixture in a fluid, in simplifying the design of the device while improving the quality of separation by obtaining a more powerful turbulence mode by increasing the size of the zones of developed turbulence due to the formation of additional circulation zones, capable of inducing microvortices, and improving the aerodynamic parameters of the device by changing to Designs of the cascade jet generator.

The specified technical result is achieved by the fact that in the method of separating a granular mixture in a fluid, which consists in the gravitational supply of particles, aerodynamic monotonically growing exposure to them at an acute angle to the vertical by a cascade of plane jets and the withdrawal of finished fractions, and each flow before aerodynamic exposure to particles the jets are transferred to the regime of developed turbulence by expanding them vertically to merge with each other with a faulty or close to it flow pattern and the formation at the beginning of each inter-jet space of all adjacent jets of two circulation zones - upper and lower - of different sizes, according to the proposal, before the formation of circulation zones, a sharp change in the direction of the stream of jets from vertical to almost horizontal, followed by their compression vertically, is carried out.

The specified technical result is also achieved by the fact that in the known device for separating granular mixture in a fluid containing a hopper with a vibratory tray, a generator installed under it with rigid walls located one below the other and at an acute angle to the vertical, the pitch and width of which increases from above to bottom connected with the air supply source under pressure and covered by the side walls, as well as fraction collectors, according to the invention, the end of each rigid wall along its entire length is provided with at an angle with an additional wall, the width of which is less than the distance between the horizontal wall adjacent to the top, which are mounted horizontally offset to form a gap relative to the lower rigid wall, and an air flow rotation chamber at the entrance to the gap, while the rotation chambers and gaps increase from top to bottom .

The proposed technical solution provides for separation in a more powerful, compared with the prototype, turbulent mode, which is characterized by an increased common turbulization zone formed by dividing one of the circulation zones into two, almost sequential, as well as due to the emergence of many zones of microvortices. Technologically, this ensures a sharp change in the direction of the air jets when they exit the generator, and structurally as a result of the formation of rotation chambers of these jets in the cavity of the generator before they exit and the formation of gap gaps directly for their passage. The achievement of the specified technical result was made possible, first of all, thanks to a complex of aerodynamic improvements of the separation device. In the proposed device for separation, the outlet openings of the generator are connected to rigid walls located horizontally offset and, accordingly, equipped with additional walls located at an angle to them in such a way that they allow the aforementioned cameras to rotate (abrupt change of direction) of the air flow, as well as slotted gaps for the passage of the resulting air jets. In this case, the division of each upper (adjacent to the outgoing jet) circulation zone occurs due to the reflection of the specified jet from the rigid wall located at an angle to the trajectory of its movement and, accordingly, its collision with the circulation zone, under the influence of which the latter is divided into two consecutive ones in the direction stream flows are circulation zones, the total length of which increases and a zone of countercurrent flows arises between them, performing the function of the zone of induction of numerous microvortices. As a result, the overall size, in particular the width, of the turbulization zones increases and they are close to the generator, the range of the turbulent flow increases, which allows several times to increase the intensity of the separation process, to thicken the layer of the separated mixture without risk of deterioration of the quality of the finished product. The presence of rotation chambers also solves the “external” problem in the design of the separator: due to the mutual placement of rigid walls that are horizontally offset and additional walls that almost completely (except for slotted gaps) cover inter-jet spaces, separated particles do not accumulate on the outer working surfaces of the separator. In addition, the rejection of the use of nozzles significantly simplifies the design of the proposed device for separation, and also eliminates the possibility of mixing different fractions - mainly due to the absence of an accelerated rectilinearly directed air flow from the nozzle - and ensures the stability of the turbulent mode.

Thus, the entire set of essential features of the proposed technical solution regarding the proposed method for separating a granular mixture in a fluid and a device for its implementation ensures the achievement of a technical result.

A further summary of the invention is illustrated by illustrative material, which shows the following: FIG. 1 is a diagram of a device for implementing the inventive method; figure 2 - cross section of the generator to explain the process of formation of the circulation zones (black circles show the zone of formation of microvortices). In figures 1 and 2, the arrows show the direction of movement of the air flow. Figure 2 dashed-dotted line shows the change in the direction of flow of the jet.

A device for implementing the proposed method for separating a granular mixture in a fluid medium consists of a hopper 1 with a vibratory tray 2 for gravitational feeding of particles into the separation zone. Under the vibratory tray 2, a jet generator 3 is installed, which is a closed volume with a set of exit slotted holes 4 of predominantly rectangular cross-section. The height of the cross section of the exit slit holes 4 and the interval between them increase from top to bottom. Rectangular rigid walls 5 are attached to the edges of the exit slit openings 4 under the fragility to the vertical and with a horizontal shift. The ends of the hard walls 5 are provided with additional walls 6, which are located at an angle to them and together with them form chambers for turning the air flow 7 and slit openings 4 for the passage of the formed air stream. The dimensions of the rotation chambers 7 and the slotted holes 4, respectively, increase from top to bottom. Fraction collectors 8 are adjacent to the generator 3 from the side of the slit openings 4. The generator 3 is connected to the air supply source under pressure P, and its side edges are covered by the side walls 9.

The proposed separation method is implemented as follows.

The mixture to be separated from the hopper 1 using a vibrating tray 2 is gravitationally fed into the separation zone. Particles of this mixture, which are in free fall, are affected at an acute angle to the vertical by a cascade of jets (shown by dashed curved lines) in the regime of developed deep turbulence, which is ensured by the faulty flow of jets and the functioning of the circulation zones. These jets are formed from the generated air flows, previously changing the direction of movement of the latter with the help of rotation chambers 7 and outputting the formed jets through the slot holes 4. When leaving the slot hole 4, each jet is vertically compressed, as a result of which it collides with the nearest circulation zone and, accordingly, the division of the latter into two circulation zones consecutive in the direction of the jet stream with the formation of the countercurrent zone - the zone of induction of numerous microvortices her. After the particles pass through a mixture of a cascade of jets and a zone of developed turbulence, the finished fractions are withdrawn.

A device for implementing the proposed method works as follows.

In the cavity of the generator 3 under the action of the air supply source, an air flow occurs. When it enters the rotation chambers 7, air jets are formed with a sharply changed direction of movement that exit through the slotted holes 4. The bulk mixture from the hopper 1 with the help of a vibrating tray 2 under the influence of gravity passes through the formed cascade of jets, during which the mixture is cleaned of extraneous impurities and the separation of its particles into fractions, after which the separated particles are lowered into the respective collectors of fractions 8.

A significant difference between the proposed method for separating a granular mixture in a fluid and, accordingly, a device for its implementation from other known solutions in this industry is the formation in the turbulization zone, as a result of a sharp change in the direction of the air jets, an additional circulation zone, which, in turn, can to induce microvortex zones, and thus increase the power and increase the stability of the turbulent mode of operation of the cascade of air jets. This difference provides a high quality separation process and, at the same time, a significant simplification of the design of the device. None of the known methods for separating a granular mixture in a fluid can simultaneously possess all of the above properties, since they generally do not provide for mechanical influence on the direction of movement of air jets, increase the turbulence zone, in particular, by forming an additional circulation zone and the automatic occurrence of microvortex induction zones.

Thus, the principle of separation of a granular mixture in a fluid and the design ensuring its implementation, proposed in this invention, lead to a qualitatively new technical result, in comparison with known analogues.

The proposed method and device does not contain any elements or processes that could not be reproduced at the present stage of development of science and technology, in particular, in the manufacture of air separators, and, therefore, are considered such that meet the criterion of "industrial applicability".

In the known sources of scientific, technical and other information, not a single method for separating a granular mixture in a fluid and a device for its implementation with the set of essential features indicated in the proposal has been found, therefore, the proposed technical solution is considered such that meets the criterion of "novelty."

A comparative analysis of the proposed invention with a well-known technical solution, taken as a prototype, showed that a sharp change in the direction of movement of air jets during the formation of their cascade leads to the appearance of new technical advantages, in particular:

- an increase in the number of circulation zones without the risk of disrupting the generation and destruction of the faulty form of the flow of jets due to the division of one of the functioning zones into two under the influence of the same jet with a changed trajectory of movement;

- the occurrence for the same reason of additional aerodynamic effects in the form of zones of microvortices that can further increase the power and size of the turbulent flow;

- avoiding the possibility of mixing treated particles of different fractions, as well as simplifying the design of the device due to the absence of nozzles with rigid walls;

- simplification of separation technology for the same reason;

- a significant improvement in the aerodynamic parameters of the device and the automatic elimination of the problem of accumulation of particles on its external working surfaces due to the presence of rotation chambers.

Since for specialists in this field of knowledge these properties are not obvious and do not follow from the existing level of technology, we can conclude that the proposed technical solution meets the criterion of "inventive step".

The economic effect of the introduction of the invention into production, in comparison with the use of the prototype, is obtained by increasing the yield of a quality product and reducing the cost of the device.

After describing the proposed method for separating a granular mixture in a fluid and a device for its implementation, specialists in this field of knowledge should be obvious that all of the above is only illustrative and not restrictive, as presented by this example. Numerous possible implementations of the proposed method and device may vary depending on the characteristics of the initial bulk material, the field of application and the desired production volumes, and, of course, are within the scope of one of the usual and natural approaches in this field of knowledge and are considered such that are the scope of the proposed technical solution.

The quintessence of the proposed technical solution is that during the separation process during the formation of the circulation zones, the jets are vertically compressed and divided into two upper circulation zones with the formation of an additional circulation zone inducing the microvortex zones, while the generator outlet openings are connected to the rigid walls of different widths installed at an acute angle with a horizontal shift, and the end of each rigid wall for its entire length is equipped with an additional with the formation of a gap for the passage of the air flow and the rotation chamber of the air flow at the entrance to the specified gap, moreover, the dimensions of the formed gaps and rotation chambers, respectively, increase from top to bottom, which together can significantly increase the separation intensity with higher quality and without involving any additional energy resources, and it is precisely this circumstance that made it possible to acquire the above-mentioned and other advantages of the proposed method and device. The use of only certain elements of the proposed technological and structural improvements, of course, limits the range of advantages listed above, and cannot be considered a new technical solution in this field of knowledge, since a different method, similar to that described, no longer requires any creative approach from designers and engineers and does not can be considered the result of their creative activity or a new intellectual property subject to protection by title documents.

Claims (2)

1. A method of separating a granular mixture in a fluid, which consists in the gravitational supply of particles, aerodynamic monotonically increasing exposure to them at an acute angle to the vertical by a cascade of flat jets and the withdrawal of finished fractions, and before the aerodynamic effects on the particles of the mixture, the flow of each jet is transferred to the developed turbulence mode by expanding them vertically to merge with each other with a faulty or close to it flow pattern and forming at the beginning of each inter-jet space all adjacent jets of two circuits the storage zones - upper and lower - of different sizes, characterized in that before the formation of the circulation zones carry out a sharp change in the direction of the flow of jets from vertical to almost horizontal, followed by their vertical compression. 2. A device for separating granular mixture in a fluid medium, comprising a hopper with a vibratory tray, a generator mounted under it, with rigid walls located one below the other and at an acute angle to the vertical, the pitch and width of which increases from top to bottom, and is connected with the air supply source under pressure and covered by side walls, as well as fraction collectors, characterized in that the end of each rigid wall along its entire length is provided with an additional wall located to it at an angle, the width of which is less than the distance between adjacent top rigid walls, which are arranged offset horizontally to define a gap relative to the lower rigid wall of the air flow and rotation chamber at the inlet to the gap, wherein the rotation chamber and the clearances increase from top to bottom.

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