RU2007232C1 - Method of pneumatic cleaning of non-ore material with fraction size up to 20 mm - Google Patents

Abstract

FIELD: non-ore material cleaning. SUBSTANCE: method comprises steps of uniform distribution of an initial material, dividing it by two flows and directing onto inclined surfaces of pouring over shelves, acting upon the material flows along their whole width by air jets, oriented one towards another at discharging the material flows off the shelves and simultaneously pushing the material flows together one to another. EFFECT: enhanced quality of cleaning process. 1 cl, 4 dwg

Description

 The invention relates to the enrichment and screening of non-metallic materials and improves the quality of the product by ensuring its effective cleaning from contaminants.

 The essence of the problem. When using aggregates with a high content of polluting particles in the production of concrete, the overspending of cement reaches 10-11%. In addition, dirty aggregates reduce the strength of concrete, lead to an increase in the mass of concrete products, and hence to excessive consumption of aggregates (crushed stone, sand). In particular, the use of dirty aggregates in road construction leads to the rapid destruction of the road surface, which leads to a large loss of roads invested in the construction and to premature wear of transport equipment.

 Existing technologies of crushing and screening plants equipped with serial equipment do not solve this problem by dry cleaning of crushed stone from adhering contaminants with a moisture content of up to 4%.

 A device of the USSR is known (a.s. N 1005898, class B 02 C 7/02, 1981) and an additional one (a.s. N 1090435, class B 02 C 7/02, 1983). A disadvantage of the known device is that it does not provide cleaning grains of crushed stone from adhering polluting particles.

 Known cleaner granular materials (and.with. N 933129, class B 07 B 7/83, 1982), including external and internal cones, loading devices, scattering plate with ring brushes, a disk with a fan wheel, ducts and drives. The disadvantage of the cleaner is the rapid wear of the brushes, and hence the low cleaning efficiency of grains of gravel.

 A known method of processing crushing waste, including dedusting and separation of the source material using an air stream in two stages, supplying exhaust air from the second stage to the first stage, moreover, in order to reduce energy consumption in the first stage, the source material is dedusted and separated at an air flow rate of 5.7 9.5 m / s, and in the second stage, the large material obtained in the first stage is separated at an air flow rate of 18-32 m / s [1].

 The disadvantage of this method is that it does not provide cleaning grains of crushed stone from adhering polluting particles.

 A known installation for the enrichment and screening of non-metallic materials, containing a feed conveyor, a crusher, a string screen and an aspiration system, which is equipped with a divider of the initial material stream located above the crusher (cleaner) in order to clean gravel grains from adhering particles, and the crusher is made in pairs parallel rotors with beats located one above the other and gable inclined distributors installed between them [2].

 The disadvantages of this device include many mechanical material-intensive drive units, independent drives, units that synchronize pairwise counter-rotation of rotors, electrical equipment that provides an independent change in the speed of rotation of pairs of rotors, a large number of replaceable bills of rotors and the complexity of replacing bills. All this significantly increases the manufacturing cost of the device and its operating costs, that is, the device has a complex structure, high material consumption and cost.

 The aim of the invention is to increase the cleaning efficiency of grains of crushed stone with a grain size of up to 20 mm in a dry way, providing high reliability of the enrichment process with an extremely simple design of the device, designed to implement the method with its minimum material consumption and cost and convenient to use.

 The goal is achieved by the fact that the air flows act on the material flows at the moment of its descent from the overflow shelves, direct towards each other and push the separated material flows.

 The impact of the air flows on the material flows at the moment of its descent from the overflow shelves, i.e. when the material is in suspension, contributes to the creation of more favorable conditions for the impact of each single grain of crushed stone from the flows and, moreover, more efficient use of the energy of the air flows directed towards to each other, which pick up gravel grains of material flows and push them together, while multiple counter tangent contact collisions of a large number of FIR grain with larger, whereby the churning occurs with large grains adhering dust particles.

 An increase in the degree of cleaning gravel grains from adhering dusty silty and clay contaminating particles occurs in the device for implementing the method, located below the distribution unit of the initial flow into two streams, made in the form of pneumatic sandblasting chambers with double-sloping inclined trays-overflow shelves and pressure pipes for supplying compressed air, located opposite each other in horizontal planes, installed in the form of whatnot, and provides for air recirculation and by connecting ducts through a fan and a device for the deposition of contaminating dust particles into a closed system.

 The location of the windows for air suction with polluting particles from the cleaning zone under the gable trays-overflow shelves at their top eliminates the ingress of sand and gravel into the suction.

 In FIG. 1 shows a general view of the installation; in FIG. 2 - node II in FIG. 1 (power unit, providing the distribution of the initial material flow in width and its division into two streams with an equal number of grains); in FIG. 3 - design of a replaceable cover; in FIG. 4 - node II in FIG. 1 (pneumatic sandblasting unit for crushed grains from adhering contaminants and pneumatic classification unit for enriched (purified) bulk material).

 The power unit provides the distribution of the initial material flow in width and the subsequent separation of the wide flow into two streams with an equal number of grains and includes a conveyor belt 1, a drum 2, a receiving shelter 3, a casing 4, side seals 5, transverse curtains 6, 7 forming a vestibule -camera in the receiving shelter 3 (curtains not shown), transverse seals 8 from the bottom of the conveyor belt 1 under the drum 2 (not shown).

 The design of the side seals 5 and the shutters 6, 7 and the transverse seal 8 are made of several layers of wear-resistant polyurethane threads in the form of brushes and curtains, of threads of the corresponding thickness and length. The power node also includes a loading tray 9, a shelter 10 with wings 11.

 The working plane of the loading tray 9 is additionally equipped with a gable adjustable visor 12, containing a bracket 13, which is provided with movement relative to the loading tray 9 and fixing in the installed positions, the supporting rib 14, fixed with the upper end to the bracket 13 by the hinge 15. At the lower end of the supporting rib 14 is made radial a window 16 with a fixing bolt 17 relative to the axis of the hinge 15, which allows you to continuously change the angle of inclination α of the bearing rib 14 with a gable visor 12 relative to the base bracket 13.

 The inclined planes 21, 22 made in the form of triangles are attached to the bearing rib 14 by means of hinges 18 and adjustable rods 19, 20. Adjustable rods 19, 20 provide the adjustment of independent angles of inclination β and γ of the planes 21, 22.

 In the inclined planes 21, 22 along the edges of the slopes, grooves 23 are made in the form of trapeziums, decreasing in size to the top of the planes, which gives the gable peak 12 in the form of a herringbone. Inclined planes 21, 22 are equipped with interchangeable linings 24 also with grooves equal to the grooves 23 of inclined planes 21, 22, which provide movement along the inclined planes 21, 22 and fixation to them, which allows you to change the live section in the gable visor (i.e. change the amount of material passed through the grooves on the working plane of the loading tray 9, in order to evenly distribute the material over the entire width of the tray). The end of the working plane of the tray 9 is equipped with estrus-grooves 25, the total width of which is equal to half the entire width of the tray 9, which ensures equal division of the wide flow of material into two streams 26, 27 with an equal number of grains in the streams (in two directions).

 Below the discharge chute 9 and leakage chutes 25, a pneumatic sandblasting unit for crushed grains of adhering dust-like polluting particles is mounted, comprising housing sections 28, 29, 30, where 28 is a receiving housing section with steeply inclined guiding tunnels 31, 32 that receive material flows 26, 27; 29 - the middle hull section, the amount of which depends on the contamination of the source material and the degree of purification of crushed stone and sand products; 30 - base case section. In the hull sections 28, 29, 30 there are fixed sloping steeply inclined trays - overflow shelves 33, 34, 35, the vertices of which are located in the vertical plane of symmetry of the hull section sections, and the lower ends over inclined planes (surfaces) are overflow shelves 36, 37, 38, 39, 40, 41, in which slotted openings 42 and nozzles 43 are made for supplying compressed (pressure) air.

 The inner surfaces of the gable steeply inclined trays-overflow shelves 33, 34, 35 and the inner surfaces of the side walls of the housing sections 28, 29, 30 form the chamber zones 44, 45, 46 for cleaning gravel grains during the oncoming vortex flight of granular granular material, i.e. sandblasting.

 In the side walls of the housing sections 28, 29, 30 under the gable steeply inclined trays-overflow shelves 33, 34, 35 in the cell zones 44, 45, 46 there are made windows with slotted openings of the Blinds 47 type, passing into the nozzles 48, for suctioning free dust particles into an aspiration system (not shown).

 At the bottom of the base case section 30, a casing 49 is fixed for collecting cleaned grains of material and transferring them to a subsequent pneumatic classification (sorting into classes 20-10; 10-5; 5-0.14 mm and associated final enrichment, - dust removal of cleaned grains). Below the casing 49, a pneumatic classification and final dedusting unit for the cleaned grains of crushed stone is mounted, including a receiving closed tray 50, a pneumatic chamber 51 made in the form of a pipe having a cross-section in the form of a rectangle with a pressure port 52 for supplying compressed air in which the guide plates 53 are placed, forming slotted holes 54 for separating the flow of compressed air into pressure jets. In the lower plane of the pneumatic chamber 51, hoppers 55, 56, 57 are fixed for collecting and outputting material classes 20-10; 10-5; 5-0.14 mm. At the second end of the pneumatic chamber 51, a window 58 is made with a flange 59 for connecting the suction system (the suction system is not shown).

 A device for enrichment and screening of non-metallic materials works as follows.

 Crushed stone mass with a grain size of 0-20 mm (or sand-gravel mixture), transported by conveyor belt 1, bends the threads of the transverse curtain 6, at the same time it is evened out along the width of the conveyor belt and introduced into the vestibule chamber of the receiving shelter, then passes under the second transverse curtain 7, where it is additionally distributed over the width of the tape 1 and enters the unloading zone (in the bending zone of the tape 1 on the drum 2). Transverse curtains 6, 7, side seals 5, transverse seal 8 of the receiving shelter 3 and the casing 4 prevent dust emission into the atmosphere.

 The preliminary equalized initial material flow falls on a two-roll visor 12 and is divided into two substreams along the intersection edge of the planes 21, 22. Each substream spreads over the entire area of its slope, while part of the grains from the substream flies directly through the grooves 23 to the working plane of the loading tray 9, and part of the grains rolls into the same grooves from the slope and, together with the grains that flew directly, move under a gable wide a visor 12 down the working plane of the tray 9. Another part of the grains rolls off the slopes, bypassing the grooves 23, also on the working plane of the tray 9, but much further from the vertical plane of symmetry of the tray 9, compared with the grains that passed through ABC 23.

 Some of the grains after hitting the surface of the gable visor 12 ricochets off even further from the middle of the tray 9 (since the angle of incidence of the grain on the inclined plane 21, 22 is approximately equal to the angle of reflection, the grains are scattered away from the gable visor 12).

 Thus, the additional supply of the working plane of the loading tray 9 with an adjustable gable visor 12, its installation in the optimal zone of material flow, the setting of the optimal angles β and γ of the ramps 21, 22 and the angle of the visor 12 itself, the implementation of the ramps 21, 22 of a triangular shape with grooves 23, the ability to change the live section of the grooves 23 due to the displacement of interchangeable linings 24 and the entire gable visor 12, which has a fir-tree shape in plan, ensures uniform distribution of the initial material flow over the entire width beyond load tray 9 (several times wider than the material flow on the belt 1 of the supply conveyor, which can significantly increase the width below the located node cleaning gravel grains from adhering contaminants, that is, increase productivity), and equipping the end of the working plane with chutes 25, the total width of which is equal to half the entire width of the tray 9, ensures equal separation of the wide flow of material into two streams 26, 27 with an equal number of grains (in two directions), which determines and ensures subsequent cleaning of the grains ebnya dusts from adhering to the downstream node sandblasting method during oncoming vortical flight two equal flows of bulk particulate material in the jets of compressed air.

 The method of pneumatic cleaning of grains of crushed stone is carried out in the following order. Two streams of granular material 26, 27, equal in width, density and number of grains, enter the steeply inclined guide tunnels 31, 32, where along the outer upper working surfaces of the first gable steeply inclined tray-overflow shelf 33, the grains of material roll onto the lower inclined surfaces - bulk shelves 36, 37, change their direction of movement at this moment, affect the flow of material jet streams of compressed air in the opposite direction, coming through slotted openings 42 from the discharge pipe 43.

 The grains of the material are picked up by jets of compressed air, instantly gain more energy and fly towards each other in the area bounded by the inner (lower) surfaces of the first gable steeply inclined tray-overflow shelf 33 and the inner surfaces of the side walls of the housing section 28, forming a cleaning chamber zone 44, where due to multiple counter tangent contact collisions, a large number of small grains of grains of sand with larger ones (since there are a majority of small grains), knocking down from large grains occurs on ipshih dust particles (m. e. practically it occurs sandblasting process gravel grains from adhering dust particles, like sand blasting process of cast metal parts from molding ground).

 At the same time, free (crushed grains) dust particles up to 0.14 mm in size are sucked out from the chamber zone 44 through slotted openings such as shutters 47 made in the side walls of the chamber zone under the gable steeply inclined tray-overflow shelf 33 into the nozzle 48 in the air stream which recirculates through a particle deposition apparatus and a fan (not shown in the drawing).

 Having extinguished the flight speed in the chamber zone 44 (due to the many collisions and ricochet from the inner surfaces of the chamber zone), the grains of material fall onto the second gable steeply inclined tray-overflow shelf 34 of the middle case-section 29 and follow downward on its outer working surfaces to the lower inclined surfaces overflow shelves 38, 39 into the zones of the following air flows, chamber zones 45.

 That is, the cycle repeats. The number of middle section housings with cleaning chambers depends on the contamination of the grains of crushed stone of the source material and the degree of cleaning that meets the requirements of GOST for crushed stone and sand.

 Having passed the last cleaning chamber-zone 46 (base case-section 30), the grains of the purified material with a size of 0.14-20 mm are collected in the downstream casing 49 and should be down to the pneumatic classification (sorting) assembly into classes 20-10; 10-5; 5-0.14 mm and associated additional enrichment - dedusting, i.e., suction of the remaining dust-like parts with a size of 0-0.14 mm into the suction system.

 Classification (sorting) of enriched grain material into crushed stone and sand occurs in the following order.

 From the casing 49, the grain material falls into the receiving closed tray 50, follows along it and falls into the zone of the jet of compressed air escaping from the slotted holes 54 between the guide plates 53 of the pressure pipe 52. Grains of material are picked up by jets of compressed air and fly along the pneumatic chamber 51, having a rectangle in cross section, where grains larger 20-10 mm in size, having greater drag, quench flight speed earlier and, therefore, earlier fall out of a horizontally flying material stream, i.e. change the trajectory and fall down into the hopper 55, from where they follow for unloading. Grains 10-5 mm in size, having lower drag, fly further and fall into the next hopper 56 and then for unloading. Grains of sand with a size of 5-0.14 mm fly even further (which helps with the associated suction of air from the pneumatic chamber 51 to the aspiration system located (fixed) at the end of the shelter box) and descend into the hopper 57 followed by unloading.

 At the same time, a passing, final re-enrichment of the material takes place, dust removal of products by suction of dust particles 0.14-0 mm in size from the pneumatic chamber 51 through the window 58 to the aspiration system, docked to the flange 59 in the air stream, which recirculates through the device of polluting particles, fan, vertical air chamber flows between bins (not shown in the drawing).

 Thus, the separation of the initial flow of crushed material with a particle size, for example, 0–20 mm, into two equal in width and number of grain flow, their direction along the gable steeply inclined trays into the zones of jet vortex countercurrent flows of compressed air provides a counter vortex flight of wide material flows, where grains of sand and gravel picked up by air jets fly towards each other and, upon contact encounters, knock down grain from the grain, adhering dust-like polluting particles, and the simultaneous suction is free dust particles of 0-0.14 mm in size, from chambers enclosing sandblasting zones of crushed stone, through slotted openings such as blinds made in the walls of the chambers, and subsequent classification of the purified material in the underlying shelter box with a stream of compressed air, as well as with simultaneous suction of dusty particles, increases the degree of purification of the grains of the material from adhering polluting particles and the efficiency of the classification of the material, which leads to an increase in the technical and economic indicators of the installation.

 Since the end result of the work is to obtain concrete aggregates that meet the requirements of GOST in terms of cleanliness, from here, in the production of concrete products, cement overrun will be reduced, which will make the economic effect of this method.

 In addition, the device for implementing the method does not contain moving parts and mechanisms, which ensures its greater reliability and ease of operation.

It should also be noted the small metal consumption of the device, the simplicity of its design and low manufacturing cost.
(56) Copyright certificate of the USSR N 1233962, cl. B 07 B 4/04, 1987.

 USSR author's certificate N 1605345, cl. B 07 B 3/02, 1987.

Claims (1)

 METHOD OF PNEUMATIC CLEANING OF NON-METAL MATERIALS WITH A LARGE OF UP TO 20 MM, including supply of the source material, subsequent uniform distribution and separation of the source material into two streams, which are moved along inclined overflow shelves, the impact of air flows on the material flows, characterized in that, in order to increase the cleaning efficiency, the impact of air streams on the material flows is carried out over the entire width of the material flows at the moment of their descent from the overflow shelves towards each other and simultaneously push currents material.

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