EP3618965A1 - Broyeur à attrition et son procédé d'utilisation - Google Patents

Broyeur à attrition et son procédé d'utilisation

Info

Publication number
EP3618965A1
EP3618965A1 EP17723749.2A EP17723749A EP3618965A1 EP 3618965 A1 EP3618965 A1 EP 3618965A1 EP 17723749 A EP17723749 A EP 17723749A EP 3618965 A1 EP3618965 A1 EP 3618965A1
Authority
EP
European Patent Office
Prior art keywords
grinding
grinding chamber
bottom wall
attritor mill
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP17723749.2A
Other languages
German (de)
English (en)
Inventor
Andrew SACCO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Attritor Mill Ltd
Original Assignee
Belmonte Investments Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Belmonte Investments Ltd filed Critical Belmonte Investments Ltd
Publication of EP3618965A1 publication Critical patent/EP3618965A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/16—Mills in which a fixed container houses stirring means tumbling the charge
    • B02C17/163—Stirring means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/16—Mills in which a fixed container houses stirring means tumbling the charge
    • B02C17/161—Arrangements for separating milling media and ground material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C2201/00—Codes relating to disintegrating devices adapted for specific materials
    • B02C2201/06—Codes relating to disintegrating devices adapted for specific materials for garbage, waste or sewage

Definitions

  • This invention relates to an attritor mill of the kind comprising a grinding container, which forms within itself a grinding chamber and a rotor arranged within said container wherein a plurality of arms extends radially from the rotor, and said arms are arranged to agitate a plurality of grinding free bodies mixed with the material to be processed.
  • the invention furthermore relates to the application of such an attritor mill to the treatment and recycling of scraps such as, for example, urban solid waste, food scraps or more generally the so- called “wet waste", remains from mowing or pruning, vegetal residues from agricultural activity, waste similar to the urban ones, FOS ("dry organic fraction") of the urban waste, scraps from mechanical selection of the urban waste, silicate or carbonate-based inorganic materials.
  • scraps such as, for example, urban solid waste, food scraps or more generally the so- called “wet waste”
  • FOS dry organic fraction
  • the drum is charged with the waste to be treated mixed with a proper quantity of steel pebbles acting as grinding bodies.
  • a second limit of this type of mills is the humidity content of the organic waste after the treatment, which remains in any way too high to allow the waste be treated in a waste to energy plant.
  • Ball or pebble-type mills often called attritor mills, are by the way known. These mills are provided with a grinding chamber wherein a rotor, by rotating about a vertical axis, randomly strikes a mass of steel pebbles mixed with other material to be treated.
  • Attritor mills having the aforementioned features are themselves already known, for example from US3131875, US3339896, US3084876, US3670970.
  • the publication WO2013/167851 further aimed to: -provide an attritor mill more efficient than the known ones, especially capable of grinding greater amounts of materials with lower power consumption compared to the known attritor mills;
  • a purpose of the present invention is to provide an attritor mill or a process to treat waste and other scrape materials that is better than that described in publication WO2013/167851 , for example because it can treat a greater amount of material in the unit of time, substantially without, however, worsening the quality of the product obtained.
  • the at least one compensation insert (200 ⁇ , 200B, 200C, 200D) forms an edge that substantially extends along the external edges of the bottom wall (29) .
  • the mill is provided with a positioning system arranged to vary the position of at least one compensation insert (200A, 200B, 200C, 200D) adjusting the width (WR) of the clearance (203) .
  • the bottom wall (29) comprises a central portion (290) and one or more external inserts (292, 294) reversibly fixed to the central portion (292) so that the external edges (2920, 2940) of these external inserts form an overall external edge of the bottom wall (29) substantially broader than the external width (291) of the central portion (290) .
  • the mill comprises a rapid fastening system that reversibly fixes the central portion (290) to one or more external inserts (292, 294) and that, in turn, comprises one or more of the following elements: one or more screws (296), other threaded connections, snap connection elements, bayonet joints or other interlocking fasteners.
  • the mill is provided with a cooling system (30) arranged to spray a coolant on the material to be treated or treated in the grinding chamber (5) .
  • the cooling system (30) is arranged to cool the material to be treated or treated contained in the grinding chamber spraying liquefied gas, such as, for example, liquid nitrogen .
  • the invention relates to an attritor mill (1) comprising:
  • a rotor (7) housed within such container (3) and provided with a bottom wall (29) that delimits the bottom part of the grinding chamber (5) , substantially extends across the rotating axis (Al) of the rotor and on substantially at least half of the cross-section surface of the grinding chamber (5) in correspondence with the bottom wall (29) ;
  • a plurality of arms (9, 9', 9") extends radially from the rotor (7) and is arranged on one or more levels with reference to the distance from the bottom wall (29) , and the attritor mill (1) is arranged to grind, reduce, mince or micronize a material to be treated such as, for example, solid urban waste, food waste, mowing or pruning scraps, vegetable waste from agricultural activity, waste similar to urban waste, FOS ("dry organic fraction”) of urban waste carrying out the following steps:
  • the attritor mill 1 is provided with at least one compensation insert (200A, 200B f 200C, 200D) inserted in a wall (13) of the grinding chamber (5) in such a way that it can reversibly and radially extend out of it and re-enter it by forming, in cooperation with the external edge of the bottom wall (29) , a variable width clearance (203) (WR) through which air and at least part of the particulate can exit from the grinding chamber (5) .
  • WR variable width clearance
  • the invention relates to an attritor mill (1) comprising:
  • a rotor (7) housed within said container (3) and provided with a bottom wall (29) that delimits the bottom part of the grinding chamber (5) , substantially extends transversally to the rotation axis (Al) of the rotor itself and substantially over at least half of the surface of the cross-section of the grinding chamber (5) in correspondence to the bottom wall (29) itself;
  • a plurality of arms (9, 9', 9") extends radially from the rotor (7) and is arranged on one or more levels with reference to the distance from the bottom wall (29) , and the attritor mill (1) is arranged to grind, reduce, mince or micronize a material to be treated such as, for example, solid urban waste, food waste, mowing or pruning scraps, vegetable waste from agricultural activity, waste similar to urban waste, FOS ("dry organic fraction”) of urban waste carrying out the following steps:
  • the bottom wall (29) comprises a central portion (290) and one or more external inserts (292, 294) fixed reversibly to the central portion (292) so that the external edges (2920, 2940) of these external inserts form an overall external edge of the bottom wall (29) that is substantially broader than the external edge (291) of the central portion (290) .
  • the process according to the invention comprises the step of spraying a coolant on the material treated or to be treated contained in the grinding chamber (5) , in order to cool such material.
  • the organic solid waste to be treated have a humidity content equal to or greater than 60 % by weight.
  • the organic solid waste to be treated are fed in continuous into the grinding chamber (5) and after having been treated they are extracted in continuous from the grinding chamber (5) , for example in the form of powder, granules, shavings, flakes, sticks, small cylinders, pellets.
  • the process according to the invention comprises the step of turning the rotor (7) during grinding at a speed of between 500 and 1500 revolutions/minute.
  • the invention relates to a procedure to disassemble an attritor mill, comprising the following operations in order:
  • Figure 1 shows a perspective view of an attritor mill according to a first particular embodiment of the invention ;
  • Figure 2 shows a first side view, partially sectioned according to plane II-II, of the attritor mill of Figure 1;
  • Figure 3 shows a top view, partially sectioned according to plane III-III, of the attritor mill of Figure 1;
  • Figure 4 shows a perspective view of the bottom wall of the rotor of an attritor mill according to a second particular embodiment of the invention
  • Figure 5 shows a second side view, partially sectioned according to plane II-II, of the attritor mill of Figure 1;
  • Figure 6 shows a perspective view of the dirt scraping protrusions present at the bottom of the grinding chamber of the attritor mills of Figures 1, 4, 7-12;
  • Figure 7 shows a side view, partially sectioned according to plane VII-VII of an attritor mill according to a third particular embodiment of the invention.
  • Figure 8 shows a section detail according to a section plane passing through the rotation axis Al of the clearance between the edge of the bottom wall and the wall of the grinding chamber of the attritor mills of the Figure 7 or 12;
  • Figure 9 shows a partially sectioned view according to an observation direction parallel to the rotation axis Al , of the grinding chamber and the compensation inserts of the mill of Figure 7;
  • Figure 10 shows a partially sectioned view according to an observation direction parallel to the rotation axis Al , of the central portion and external inserts of the bottom wall of the mill of Figure 7;
  • Figure 11 shows a section view according to a section plane passing through the rotation axis Al of the central portion and of the external inserts of the bottom wall of the mill of Figure 10;
  • Figure 12 shows a first side view, partially sectioned according to a section plane XII-XII passing through the rotation axis Al of a fourth embodiment of an attritor mill according to the invention.
  • Figures 1-6 relate to an attritor mill, indicated with the overall reference 1, according to a first particular embodiment of the invention.
  • the attritor mill 1 comprises a grinding container 3 which forms in its inside a grinding chamber 5 and a rotor 7 housed inside said chamber ( Figure 2) .
  • the grinding container 3 can be made up of, or any way can comprise a metal sheet shell, preferably in a cylindrical shape.
  • the grinding chamber 5 has a substantially cylindrical shape.
  • the ratio between the height HC and the diameter DC of the cylindrical grinding chamber 5 is preferably greater than 0.8, more preferably greater than 1 and for example comprised between 0.8 and 1.3.
  • the rotor 7 preferably comprises a pivot or central shaft 70 and can be fixed to the rest of the mill 1 through a bearing inserted on the rotor itself ( Figure 2, 5) .
  • the rotor 7 is provided with a bottom wall 29 that delimits and closes the bottom part of the grinding chamber 5 and is arranged to protect the bearing from dust, granules or other particles coming from the grinding chamber itself.
  • the bottom wall 29 can be obtained, for example, from a more or less planar disk ( Figure 2, 3, 5) .
  • the bottom wall 29 preferably lies in a plane substantially perpendicular to the rotation axis Al of the rotor itself, is integrally fixed to the rest of the rotor 7 and rotates together with it.
  • the bottom wall 29 substantially covers at least half of the bottom surface or of the cross section of the grinding chamber.
  • a plurality of arms 9, 9', 9" extends radially; such arms are arranged above the plate 29 and on one or more determined levels with reference to their distance from the plate 29 itself according to the direction of the rotation axis Al of the rotor.
  • the attritor mill is arranged to grind, crush, mince or micronize a material to be treated, such as for example urban solid waste, food scraps, waste with a high content of animal or vegetal tissues, remains from mowing or pruning, vegetal residues from agricultural activity, waste similar to the urban ones, FOS ("dry organic fraction") of the urban waste, by actuating the following steps:
  • the grinding free bodies 11 can be for example spheres, pebbles, pellets, balls, cobbles, granules of materials such as steel, copper or other metals, metal materials, stones.
  • the grinding free bodies 11 can also be other bodies having various and more sharp-cornered shape, such as for example waste and metal scraps, nails, screws and bolts; however, these grinding free bodies as well, after a certain permanence in the grinding chamber, assume shapes even and even more rounded and more similar to pebble, cobbles or bullets.
  • the mill 1 is arranged to rotate the rotor 7 on itself, during the normal operation, about a substantially vertical axis Al, or at least having an inclination with respect to the vertical not greater than about 45° .
  • the mill 1 is also provided with one or more first extraction openings 10 each arranged to allow the exit of material treated in the chamber itself and possibly withholding the grinding free bodies 11 within the grinding chamber 5.
  • the one or more extraction openings 10 are located at least in the lower portion of the grinding chamber 5, this expression meaning the lower half of the chamber 5.
  • each first extraction opening 10 is preferably located at a height HI equal to or lower than:
  • the height HI is measured with reference to the lower zones of the bottom surface 29.
  • the height HI of the upper edge of the topmost first extraction opening 10 is preferably less than or equal to 0.2 times the internal average or maximum diameter DC of the grinding chamber; more preferably, less than or equal to 0.1 times the diameter DC and even more preferably equal to the height HP described further below.
  • the bottom wall 29 can extend radially at least so as to reach the one or more lateral walls 13.
  • the bottom wall 29 extends radially beyond the one or more lateral walls 13 and even outside of them ( Figures 2, 5) .
  • the bottom wall 29 extends radially beyond the one or more lateral walls 13 for a length greater than or equal to 2 millimetres and/or 0.002 times the DC diameter of the chamber 5.
  • the bottom wall 29 extends radially beyond the one or more lateral walls 13 for a length greater than or equal to 0.003 times the diameter DC and even more preferably greater than or equal to 0.01 times the diameter DC.
  • one or more of the first extraction openings 10 can have the form of a perimeter slit that extends around the lateral walls 13 of the grinding chamber 5.
  • the mill 1 can be provided with just one first extraction opening 10 located substantially in correspondence or in proximity to the external edge of the disk that forms the bottom wall 29; the first extraction opening 10 is in practice a slit formed by the bottom wall 29 and by the lower edge of the lateral wall 13 that ends slightly above the bottom wall 29.
  • Each of the first openings 10 has a height HP clearly shorter than the diameter or the minimum linear dimension of the grinding masses.
  • the height HP is preferably comprised between 0.05-50 millimetres and more preferably comprised between 1-10 millimetres or between 2-5 millimetres .
  • the ratio HP/DC between the height HP of the first opening 10, and the diameter DC of the chamber 5 is preferably comprised between 0.002-0.07 times, more preferably between 0.005-0.02 times or between 0.002-0.006 times.
  • the ratio SA1/SPL between area SA1, that is the total area of the all the first openings 10, and the SPL area of the wall or of the lateral walls 13 of the chamber 5 is preferably comprised between 0.001-0.08 times, more preferably between 0.001-0.02 times and, for example, between 0.003-0.008 times.
  • the slit 10 or the other first extraction opening 10 contributes to increasing the capacity of ground material up to 30-40% and significantly reducing the wear and tear both of the grinding bodies and the grinding chamber 5 and the risks of jamming of rotor 7 caused by the grinding bodies or other extraneous bodies, so that the author of the present invention was able to extract up to about 70% of the total capacity of ground material from the hole 10 or the other first extraction opening 10 located at the height of the bottom wall 29, probably aided by the fact that the ground material is generally more rarefied in the upper part of chamber 5 and denser and more concentrated in the lower part of chamber 5.
  • Each supporting protrusion 19, 19' preferably has a shape selected from the following group: semi- spherical, spherical cap ( Figures 2, 3, 5), stud-like or other round protrusion, in the shape of a smooth crest or rib such as, for example, a cylinder-shaped surface portion ( Figure 4) .
  • Protrusions 19, 19' having a substantially rounded plan such as semispherical-, spherical cap- or stud ⁇ like protrusions can be fixed more easily to the bottom wall 29.
  • the supporting protrusions 19 can extend radially relative to the rotation axis Al of the rotor ( Figure 4) .
  • the supporting protrusions 19 can extend from the centre outwards of the grinding chamber, even though not in radial directions and extend, for example, in a spiral manner.
  • the protrusions 19, 19' are much less worn and wear much less the grinding bodies 11 compared, for example, to the supporting protrusions 19 with sharper edges described in the publication WO2013/167851A1.
  • the supporting protrusions 19 have a height HB preferably comprised between 1-8 centimetres, and more preferably between 3-6 centimetres ( Figure 2) .
  • the ratio HB/DC is preferably comprised between 0.01-0.07 times and more preferably between 0.02-0.04 times and, for example, equal to 0.03 times wherein HB is the height by which each supporting protrusion 19 extends beyond and above the rest of the bottom wall 29.
  • the supporting protrusions 19 are placed close one to another and in groups of three and substantially placed at the vertexes of an equilateral triangle ( Figure 2) .
  • the supporting protrusions 19 have semi- spherical, spherical cap- or smooth stud-like shape, they have a maximum diameter or width in a plan view preferably comprised between 5-15 centimetres, and even more preferably between 7-13 centimetres and, for example, equal to 10 centimetres.
  • the ratio DB/DC is preferably comprised between 0.05-0.2 times and more preferably comprised between 0.08-1.4 times, where DB is the maximum diameter or length of a stud in a plan view and DC is the internal average or maximum diameter of the grinding chamber 5.
  • the four groupings are preferably and substantially located at the ends of a cross having substantially orthogonal arms ( Figure 3) .
  • Said rounded shapes of the supporting protrusions 19 allow the mill 1 to grind predominantly by impact or by friction depending on the rotation speed of the rotor 7.
  • the mill 1 can be provided with at least a second extraction opening 17 arranged at least in the upper part of the grinding chamber 5 and arranged to allow for the material treated into the chamber itself to exit and/or retain the grinding free bodies 11 inside the grinding chamber 5, wherein the lower edge 170 of the at least a second extraction opening 17 is located at a height H3 same as or lower than:
  • the lower edge 170 of the at least one second extraction opening 17 is located at a height H3 lower than or equal to 0.5 times the average or maximum internal diameter DC of the grinding chamber 5.
  • the at least one second extraction opening 17 extends for a height H2 greater than or equal to 0.5 times, more preferably greater than or equal to 0.6 times or even more preferably greater than or equal to 0.75 times the average or maximum internal diameter DC of the grinding chamber 5.
  • the grids or other second extraction openings 17 extend over at least one third of the perimeter of the cross-section of the walls 13 of the grinding chamber 5, wherein these cross sections are the ones wherein the openings 17 are present and are considered perpendicular to the rotation axis Al of the rotor 7.
  • the grids or other extraction openings 17 extend over at least half and, more preferably, over at least one three fourths of the perimeter of the cross-section of the walls 13 of the grinding chamber 5.
  • the second opening 17 or the second extraction openings 17 resulted to be particularly efficient to increase flow rate of the air and particulate removed from the chamber 5 during the grinding, increasing accordingly the efficiency of the mill 1.
  • the first 10 and the second evacuation openings 17 contribute to lowering the temperature within the chamber 5.
  • the first extraction openings 10 can also be provided with grids or can form the grids themselves or other filtering barriers having analogous function as of the grids or other second extraction openings 17.
  • the arms of the rotor 9 which are more distant from the bottom of the grinding chamber 5 are substantially shorter than the arms 9', 9" which are closer to the bottom of the grinding chamber (5) ; in this way the rotating arms 9, 9', 9" tend to rise, and to maintain more raised, the bulk of the grinding free bodies 11, thus increasing the efficiency of the grinding .
  • the length LB of the arms 9, 9', 9" of the rotor progressively reduces by moving away ideally from the bottom of the grinding chamber 5 ( Figure 2); thus the ability of the mill 1 of rising and of maintaining raised the bukl of the grinding free bodies 11 increases .
  • the various arms 9, 9', 9" can be fixed to the rotor so as to substantially lie in two ideal mutually orthogonal planes.
  • the rotor 7 can be driven for example by a proper electric motor, not shown, arranged below the grinding chamber 5.
  • the attritor mill 1 is arranged to make the rotor 7 rotate on itself, for example through the aforementioned electric motor, at a speed preferably comprised between 500 and 1500 rev/min, and more preferably comprised between 800 and 1200 rev/min.
  • the length LB of the arms 9, 9', 9" of the rotor progressively reduces according to a linear law by moving away ideally from the bottom of the grinding chamber 5.
  • the waste or other material to be treated are introduced into the grinding chamber from the top, for example through the supplying duct 15 which preferably is substantially vertical ( Figure 1) .
  • the attritor mill 1 is advantageously provided with a feeder (not shown) arranged to push the material to be treated into the grinding chamber 5.
  • Such a feeder can comprise or consist of a screw or Archimedean screw feeder, a piston, a hydraulic or mechanical pusher, a volumetric pump.
  • Such a screw, Archimedean screw or hydraulic pusher can be housed for example in the same supplying duct 15.
  • Each arm 9, 9' , 9" can have for example substantially circular cross sections, and more in particular can be in the shape of a cylindrical rod.
  • the second extraction openings 17 are preferably closed by appropriate grids, sieves, filters in general or other filtering elements that can be crossed by the outgoing air flow from the grinding chamber but hold the solid particles larger than a pre-determined granulometry .
  • the extraction grid or grids 17 have holes or meshes of dimensions such as to let the particles of treated material of the desired dimensions pass, and on the other hand to retain the grinding free bodies 11 inside the grinding chamber 5; preferably the holes or meshes of each of the extraction grids 17 have a diameter, or anyway a maximum length or width, equal to or less than 2 cm, more preferably comprised between 3 mm and 9 mm and even more preferably equal to about 6 mm .
  • Adopting holes or meshes of the extraction grids of about 6 mm treating organic waste and/or urban solid waste the particle size of the extracted waste ranges from 100 microns to 5 mm.
  • the attritor mill 1 comprises a suction system arranged to suction and extract the powders or other particles of treated material from the grinding chamber 5, and the suction system comprises a fan or other aspirator 21 located outside the grinding chamber itself ( Figure 5) .
  • the grinding container 3 can be enclosed in an external casing 23 capable of assuring a proper pneumatic seal, and the inside of the casing 23 can be fluidically connected to the fan or other suction 21 through a collecting duct 25 in order to create a pneumatic depression in the internal space 22 of casing 23 and outside of the mill 1.
  • the fan or other suction 21 is preferably motorized, for example driven by an electric motor.
  • the attritor mill 1 is provided with a grid cleaning system arranged to keep clean the at least one extraction grid 17 or at least to reduce its clogging.
  • the grid cleaning system comprises at least one nozzle 27 arranged to emit air jets towards the at least one extraction grid.
  • the grid cleaning system comprises a plurality of nozzles 27.
  • the attritor mill 1 is furthermore provided with a logic unit programmed or anyway arranged to activate in sequence, for example one at a time, the nozzles 27; the fewer nozzles are simultaneously activated, the less the flow set between the grinding free bodies 11 and the material to be treated breaks .
  • the attritor mill 1 is provided with a temperature control and adjusting system arranged to detect the temperature in the grinding chamber 5 during the functioning of the mill and to control it, preferably in real time, keeping it within a desired range of values, for example between 50-90 degrees C.
  • control and adjusting system of the temperature can comprise one or more of the following subsystems:
  • a cooling system of the grinding chamber that can be for example a water-, air- or other thermovector liquids or aeriforms ;
  • a logic unit arranged to control and vary the rotation speed of the rotor 7, the aforementioned measuring device and/or cooling system.
  • the cooling system can comprise one or more conduits lapping the walls of the grinding chamber 5 and crossed by suitable cooling liquid.
  • the cooling system comprises one or more cooling nozzles 30 ( Figure 1) , each of which are arranged to sprinkle for the materials contained in grinding chamber 5 with the appropriate coolant ( Figure 1) .
  • the nozzle or nozzles 30 can be arranged to give out liquid nitrogen jets that, becoming gaseous, cool the contents of the grinding chamber, both the waste yet to be ground or partially ground and the waste already ground.
  • the attritor mill 1 can be advantageously provided with one or more heating elements 33 that provide additional heat to the material to ground contained in chamber 5 ( Figure 5) .
  • the heating elements 33 can comprise one or more of the following elements: Joule effect heating resistors, infrared ray lamps, heat exchangers internally crossed by a gas or a thermovector liquid that transfers heat to the material to be ground, and electrical resistance with a ceramic band.
  • the heating elements 33 are preferably arranged on the lateral walls 13 of the grinding chamber 5 ( Figure 5) , even if they can clearly be arranged even on or at the bottom 29 of the chamber 5, in arms 9, 9', 9" or in other parts of the rotor 7.
  • one or more dirt scraping protrusions 31 are present that serve to clean off any build-up of materials to be ground, ground materials or other dirt, if any, that is deposited on the lower side of the bottom wall 29, thus reducing the maintenance needs of the mill and lengthening its operative life ( Figure 6) .
  • the protrusions 31 can be shaped, for example, as ribs or studs, the top of which forms a crest that preferably has a sharp edge.
  • one or more of the first extraction openings 10 are located below the bottom wall 29.
  • the first openings 10 can also be on the sub- floor 8, if any, of the grinding chamber below the bottom wall 29, such as, for example, in the embodiment of Figure 12.
  • the sub-floor 8 can also be completely absent ( Figure 7) ; in this case, the mill 1 is provided with the only opening 10 delimited by the simple extension of the walls 13 of the grinding chamber below the bottom wall 29.
  • one or more first extraction openings 10 can advantageously form an overall pass-through section -wherein such expression means the flow area of the opening 10 if just one of such opening is present, or the sum of the pass-through sections of all the first openings 10 if more than one opening is present - greater than or equal to 0.2 times and even more preferably greater than or equal to 0.8 times, the cross-section area of the grinding chamber 5 at the height of the bottom wall 29.
  • the mill 1' , 1" is advantageously provided with a suction conduit 110 arranged to suck air from the grinding chamber 5 toward an area located below the bottom wall 29 ( Figure 7) .
  • this suction conduit 110 extends for at least 10 cm, more preferably for at least 20 centimetres, more preferably for at least 30 centimetres, and even more preferably for 100 centimetres downwards with reference to a direction parallel direction to the rotation axis Al .
  • this suction conduit 110 preferably extends advantageously downward for a height of at least 0.2 times, 0.5 times, once, 2 times the average or maximum diameter DC of the grinding chamber 5.
  • the conduit 110 can be in fluidic communication with the pneumatic depression ambient 22, with a vacuum pump or any other pneumatic depression generators.
  • the bottom wall 29 can have advantageously such an extension that the radial clearance WR between its peripheral edge and the grinding chamber walls 5 has a width WR of between one and five times the diameter or however maximum width or length of the aforementioned holes or meshes of each of the extraction grids 17.
  • the distance between its peripheral edge of the bottom wall 29 and the walls of the grinding chamber 5 are comprised between 3 and 3.5 times the diameter, or anyway a maximum length or width, of the aforementioned holes or meshes of each of the extraction grids 17.
  • the radial clearance 203 WR is preferably between 0.1-1 millimetres, or between 0.2-0.8 millimetres or between 0.3-0.6 millimetres.
  • the peripheral edge of the bottom wall 29 is flared so that the distance between the edge of the plate and the walls of the grinding chamber 5, according to a radial direction with respect to the rotation axis Al of the rotor, increases by ideally moving towards the bottom of the grinding chamber, preventing the particles coming from the grinding chamber 5 from getting stuck between the edge of the bottom wall 19 and the walls of the grinding chamber 5 and permitting instead their outflow through proper drains downstream of the bottom wall 29 itself.
  • the attritor mill 1', 1" is advantageously provided with one or more compensation inserts 200A-200D inserted in corresponding slots provided in the walls that delimit the grinding chamber 5 ( Figures 8, 9), so as to be able to radially slide into said slots.
  • Inserts 200A-200D can be present, for example, in the number four and can be arranged so that their internal edge is at the height of the external edge of the bottom wall 29 and is substantially facing and overlapping it .
  • the inserts 200A-200D can be moved radially (Arrows F1-F4) in order to move the internal edge closer to the edge of the bottom wall 29 and restore the original value of the width WR of the radial clearance 203 as the edge gets worn.
  • Each compensation insert can have the form of a simple flat plate in an arch-shape.
  • each compensation insert 200A- 200D is made of a relatively hard material, such as an appropriately treated steel.
  • the bottom wall 29 advantageously comprises a central portion 290 and one or more external inserts 292, 294 reversibly fastened to the central portion 292 so that their external edges 2920, 2940 form an overall external edge of the bottom wall 29 that is broader than the external edge 291 of the central portion 290 ( Figures 10, 11) .
  • edges 2920, 2940 contains the external edge 291 of the central portion 290.
  • edges 2920, 2940 is substantially circular.
  • Each external insert 292, 294 can substantially have the form of a substantially flat plate, even if it has a variable thickness and a curved overall shape.
  • Each external insert 292, 294 is fastened to the central portion 292 through appropriate quick fastening systems 296 in order to be easily and quickly disassembled and, for example, they are screwed, hooked or somehow fastened to the lower side of the central portion 292 ( Figure 11) .
  • the aforementioned quick fastening systems can clearly comprise systems different from the screws 296 or snap systems, and can comprise, for example, other threaded, bajonet or eccentric connections.
  • the central portion 290 lacking external inserts 292, 294 has coupling clearances with walls 13 of chamber 5 that are much greater and looser than the bottom wall 29 provided with the external inserts 292, 294.
  • the external inserts 292, 294 allowed the author of the present invention to also reduce the mill maintenance time by 2-3 hours, disassembling and reassembling the rotor 7.
  • the invention relates to a process for treating organic solid waste such as for example urban solid waste, food scraps, remains from mowing or pruning, vegetal residues from agricultural activity, waste materials similar to the urban ones, FOS ("dry organic fraction") of the urban waste, comprising the following steps:
  • an attritor mill 1, 1' , 1" in its turn comprising a grinding container 3 which forms a grinding chamber 5 in its inside and a rotor 7 housed inside said container 3, wherein a plurality of arms 9, 9', 9" radially protrudes from the rotor 7;
  • Attritor mill 1, 1' , 1" particularly suitable for making plants for treating waste or other materials, relatively small-sized, hence particularly suitable for being installed on islands, mountain zones or other places difficult to be reached or with scarce energetic availability, or again particularly suitable for being supplied with solar, aeolic energy or with other alternative energies.
  • the organic solid waste to be treated are introduced in continuous into the grinding chamber 5 and after being treated they are extracted in continuous from the same grinding chamber 5.
  • the urban organic solid waste, or other material to be treated are introduced into the grinding chamber 5 through the supplying duct 15, for example through the aforementioned Archimedean screw or pusher and mixed with the grinding free bodies 11 and with the mass of waste - or other material to be treated - already present in the chamber 5 and already partially ground .
  • a good part of the mechanical energy provided by the rotor 7 directly or through the grinding bodies is converted into thermal energy that heats the chamber 5 and its content, in particular the grinding free bodies 11 and the waste - or other material to be treated - ground or semi-ground.
  • Another part of the ground particles flows down to the bottom wall 29 and therefore exits radially through one or more of the first extraction openings 10 in the lower part of the grinding chamber 5, for example sucked thanks to the pneumatic depression present in the space 22 and/or launched by centrifugal force.
  • the edge of the bottom surface 29 protruding from the slit - or the first opening- 10 facilitates the downward exit of the ground material and increases the quantity of the material that can be ground for the unit of time.
  • the attritor mill 1 can be stopped and a user, for example through the door 28 can reach the grinding chamber 5, clean it from possible encrustations or dirt and extract the grinding free bodies (Figure 1) .
  • the grinding free bodies 11 can thus be sieved eliminating those that became too small due to wear and tear, afterwards they can be re-introduced into the chamber 5 possibly together with fresh grinding free bodies 11.
  • Both the first extraction openings 10 and the new sizes of the extraction grids 17, determined by the heights HI and H2 increase the overall flow area through which the ground product is extracted from the grinding chamber, increasing the quantity of materials that the mill 1 is able to treat in comparison with the known mills.
  • the first extraction openings 10 located by the bottom wall 29 also allow the heavier and less volatile ground particles to be extracted more quickly, reducing the formation of particle deposits and crusts at the same time in the space between any sub-floor 8 and the bottom wall 29.
  • a part of the ground particles - mdicatively up to about 70% - basically their less volatile fraction flows down to the bottom wall 29 through the radial gap present between the external edge of the wall and the walls of the grinding chamber 5 and then possibly through one or more of the first extraction openings 10' , 10" in the lower part of the grinding chamber 5, for example sucked by the pneumatic depression present in space 22 or in any case downwards through the suction conduit 110.
  • the first extraction openings 10' , 10" located in below the bottom wall 29 and/or the suction conduit 110 allow the heavier and less volatile ground particles to be extracted quicker, reducing the formation of particle deposits and crusts at the same time in the space between the sub-floor 8 and the bottom wall 29.
  • a mill 1, 1' , 1" according to the invention is particularly suitable for operating in continuous, with a continuous inflow of waste or other materials to be treated into the grinding chamber 5 and a continuous outflow of desiccated particles from the grids 17, requiring technologies relatively simple in order to automate the process.
  • an attritor mill according to the invention can also operate discontinuously, for example by supplying the material to be treated and extracting the treated material according to the batch modality.
  • the supporting protrusions 19 can be shaped of not only as rectilinear oblong ribs, but for example have also curved shapes.
  • the supporting protrusions 19 can be clearly placed at the vertexes even of a non-equilateral triangle or other types of geometric figures or be arranged for example in a star-like, spiral-, staggered arrangements or concentric circles .
  • the used materials, as well as their dimensions, can be any according to the technical needs .

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)

Abstract

L'invention concerne un broyeur à attrition (1) comprenant un récipient de broyage (3) et un rotor (7). Une pluralité de bras (9, 9', 9") s'étendent radialement à partir du rotor (7). Le broyeur à attrition (1) est conçu pour broyer, hacher ou triturer un matériau à traiter, par exemple des déchets solides urbains, des déchets alimentaires, des déchets de fauchage ou de taille et des résidus végétaux de l'agriculture, au moyen des étapes suivantes : C.1) le mélange du matériau à traiter avec une pluralité de corps libres de broyage (11) dans la chambre de broyage ; C.2) la rotation du rotor sur lui-même de sorte que ses bras frappent les corps libres de broyage et que ces derniers frappent le matériau à traiter. Le matériau traité peut sortir de la chambre à travers les ouvertures d'extraction (10) situées au moins dans la partie inférieure de la chambre de broyage (5).
EP17723749.2A 2017-05-05 2017-05-05 Broyeur à attrition et son procédé d'utilisation Pending EP3618965A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB2017/051268 WO2018203022A1 (fr) 2017-05-05 2017-05-05 Broyeur à attrition et son procédé d'utilisation

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EP3618965A1 true EP3618965A1 (fr) 2020-03-11

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WO (1) WO2018203022A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3081732B1 (fr) * 2018-05-29 2020-09-11 Deasyl Sa Broyeur tridimensionnel, son procede de mise en œuvre et ses utilisations
CN110280373B (zh) * 2019-05-21 2020-11-17 管炜 一种选矿自动阶层式分目磨碎装置及使用方法
CN110201782A (zh) * 2019-06-17 2019-09-06 苏州楠涵纺织后整理科技有限公司 一种自动化纺织机械用染料研磨装置
EP3981513B1 (fr) * 2020-10-12 2023-07-05 Comec Srl Dispositif de broyage à immersion
CN112934381B (zh) * 2021-02-08 2022-12-16 深圳市宏源茂实业有限公司 一种新型墙体材料加工用球磨机
CN113210083B (zh) * 2021-05-12 2022-06-10 威海职业学院(威海市技术学院) 一种精细研磨设备
GB2617564A (en) * 2022-04-11 2023-10-18 Attritor Mill Ltd Attritor mill and process for processing a material therewith

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
WO2013167851A1 (fr) * 2012-05-10 2013-11-14 Belmonte Investments Limited Broyeur par frottement et son procédé d'utilisation

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