Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
  • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
  • B07B1/12—Apparatus having only parallel elements
  • B07B1/14—Roller screens
  • B07B1/15—Roller screens using corrugated, grooved or ribbed rollers
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/02—Pretreatment of the raw materials by chemical or physical means
  • D21B1/023—Cleaning wood chips or other raw materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N1/00—Pretreatment of moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/08—Moulding or pressing
  • B27N3/18—Auxiliary operations, e.g. preheating, humidifying, cutting-off

Definitions

• the present invention concerns a ring to select incoherent material and the corresponding selector machine.
• the incoherent material to be selected is preferably of the wood type, for example wood shavings, wood chips, crushed wood, wood residues or similar or comparable material.
• the invention is used in machines designed to select incoherent material in order to then be able to use fractions with differentiated granulometry and to remove polluting materials, for example, but not only, inert materials such as stones, glass, sand, etc.
• recovered wood from which chip can be obtained, can be wood coming from various sources and therefore often having a high quantity of polluting materials.
• recovered wood can come from the processing of the wood used to obtain panels or furniture; from the recovery of packaging, pallets, bins and crates; from beams, rafters or planks; from waste treatment and separate collection.
• wood chips are obtained from felled trees of various sizes that have in themselves, or are associated with, sand or small stones.
• screening machines have been known in the state of the art for some time, designed to separate and select chips and particles on the basis of their granulometry from an incoherent or fibrous mass, whether dry or wet, generally but not exclusively of wood-based material.
• Screening machines are also known which are configured to remove polluting materials, inert and not, from this incoherent mass in order to obtain better quality wood material for subsequent processing.
• These machines typically provide screens with a mesh or disc, or roll-type screens with one or more levels, or tiers, of selection elements which define a bed onto which the material to be selected is fed.
• Roll machines of this type are described, for example, in patent EP 1007227, in the name of the present Applicant, in which a progressive series of rolls is provided, in cascade, with zig-zag discharge gaps of different amplitudes, in order to obtain the subdivision of the material to be selected into different sizes.
• known types of roll machines are not able to meet the need for a more thorough cleaning of the wood material, especially of fine polluted particles such as sand, and the need to produce less wood waste.
• known roll-type machines are generally very bulky and have a large number of components to define a cascade selection of the incoherent material for different sizes thereof.
• Applicant therefore set himself the purpose of improving the selection activity of known roll-type machines for the selection of both recycled and fresh wood material.
• the purpose of the present invention is to improve the selection of chips both by improving the elimination of possible inert polluting materials and also by allowing the recovery of such inert polluting materials, for example with an energy function.
• the Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.
• the present invention concerns a ring to select incoherent material in the form of chip, in particular wood-based, and to eliminate inert materials contained in the incoherent material.
• a ring comprises a circumferential cusp and two circumferential base surfaces connected to the cusp by means of circumferential lateral surfaces.
• the base surfaces have a smaller diameter than that of the cusp.
• the ring is configured to rotate around an axis of rotation and the lateral surfaces have a plurality of circumferential teeth each defined respectively by a conical annular surface followed by a cylindrical annular surface, wherein the cylindrical annular surface is directed parallel to such axis of rotation.
• Such circumferential development substantially defines a serrated development that follows the development of the lateral surfaces.
• these circumferential teeth promote the drawing of the material to be selected, also thanks to a shape that has a cross-section with a substantially trapezoid shape.
• the ring has a cross-section, with respect to the axis of rotation itself, which is substantially triangular, reducing the diameter toward the axis of rotation.
• the ring is normally, although not necessarily, axial symmetrical with respect to the axis of rotation.
• the lateral surfaces have a symmetrical development with respect to a lying plane of the cusp. In this way, the ring is balanced during the rotation and can be easily used in series.
• the lying plane of the cusp is normally, but not necessarily, perpendicular to the axis of rotation.
• the lateral surfaces have an asymmetrical development with respect to the lying plane of the cusp. In this way, a single ring can perform different types of selections on the two lateral surfaces.
• the ring can be asymmetrical both in terms of position of the lying plane of the cusp, and also in terms of number and size of the circumferential teeth.
• a machine to select incoherent material in the form of chip, in particular wood-based, and to eliminate inert materials contained in the incoherent material comprises a plurality of rolls disposed adjacent and distanced laterally in a direction of feed of the material to be selected, in order to define a selection plane thereof.
• the rolls are each provided with a drive shaft configured to rotate around an axis of rotation and a plurality of rings as above adjacent to each other along the drive shaft to form a plurality of circumferential cusps alternated with a plurality of circumferential grooves.
• the circumferential grooves of the roll are defined by two circumferential base surfaces of two respective adjacent rings alternated and located substantially on the same selection plane.
• the rolls are adjacent so that the cusps of one roll co-penetrate into the grooves of the adjacent roll, defining a discharge gap with a substantially zig-zag development.
• the adjacent rolls produce a serrated or jagged discharge gap with a zig-zag development allowing to obtain a selection according to shape, as well as size.
• the machine has discharge gaps with increasing amplitude in the direction of feed, generating a progressive selection of the incoherent material in terms of size and shape.
• the machine comprises two or more groups of adjacent rolls wherein the groups of rolls are substantially the same.
• each group of rolls has rings that have lateral surfaces with circumferential teeth different, in number and size, from the group of rolls provided in succession in the direction of feed. Furthermore, there is provided a variation of the amplitude of the discharge gap between one roll and the subsequent one in the direction of feed of the material to be selected and according to the selection provided.
• the discharge gap has a minimum amplitude comprised between 0.5 mm and 1.5 mm and a maximum amplitude comprised between 4 mm and 16 mm, advantageously between 8 mm and 12 mm, preferably between 4 mm and 6 mm.
• the minimum amplitude is, advantageously but not necessarily, correlated to the number of circumferential teeth present on each lateral surface.
• the minimum amplitude is correlated to a number of circumferential teeth greater than those connected to the maximum amplitude.
• the invention allows to obtain a continuous selection plane passing from one degree of selection to the next.
• the invention therefore allows to obtain a more compact and efficient machine and a more thorough selection of the material, at the same time also recovering fine fractions which cannot be selected with current technologies.
• - fig. 1 is a lateral view of a ring to select incoherent wood-based material and to eliminate the inert materials in accordance with the present invention
• - fig. 2 is a view along section line II - II of the ring of fig. 1;
• - fig. 3 is a front view of the ring of fig. 1;
• - fig. 4 is a top view of a machine to select incoherent wood-based material and to eliminate the inert materials in accordance with the present invention
• - fig. 5 is a view of an enlarged detail of fig. 4;
• - fig. 6 is a view of another enlarged detail of fig. 4;
• - fig. 7 is a view of another enlarged detail of fig. 4.
• a ring 10 to select incoherent material in the form of chips, in particular, but not exclusively, wood-based, and to eliminate the inert materials contained in the incoherent material is shown by way of example in figs. 1-3.
• incoherent material here and hereafter in the description we generally mean a loose material with homogeneous or non-homogeneous sizes, preferably, but not necessarily, wood-based and possibly also containing polluting material, for example, but not only, inert material such as sand, stones, glass and suchlike.
• chips here and hereafter in the description we generally mean any type of recycled or fresh wood-type incoherent material suitable to be selected by means of roller screens, that is, for example wood flakes, wood fragments, forest residues, wood chips, sawdust or sawmill scraps, or suchlike.
• the ring 10 comprises a circumferential cusp 14 and two circumferential base surfaces 15 connected to the cusp 14 by means of circumferential lateral surfaces 17.
• the base surfaces 15 have a smaller diameter than that of the cusp 14.
• the base surfaces 15 can be cylindrical or sub-cylindrical.
• the diameter of the base surfaces 15 can be comprised between 50 mm and 80 mm, and the diameter of the cusp 14 can be comprised between 100 mm and 130 mm.
• the ring 10 is configured to rotate around an axis of rotation X.
• the axis of rotation X can be perpendicular to a lying plane of the circumferential cusp 14.
• the lateral surfaces 17 have a plurality of circumferential teeth 20 defined respectively by a conical annular surface 19 alternating with a cylindrical annular surface 18.
• This cylindrical annular surface 18 is directed parallel to the axis of rotation X of the ring 10.
• a ring 10 can be keyed onto a drive shaft 12 by means of connection means 25, for example of the key type.
• the ring 10 can be made in a single body with the drive shaft 12.
• the ring 10 has a substantially triangular or V-shaped cross- section with the vertex, defining the cusp 14, facing toward the outside with respect to the drive shaft 12 and the two circumferential base surfaces 15 defining the base points of the triangular section.
• the ring 10 can have a section with an isosceles triangle shape with an angle at the vertex, defining the cusp 14, comprised between 45° and 75°, preferably between 60° and 70°.
• the circumferential teeth 20 have a cross-section, with respect to the axis of rotation X, with a substantially trapezoid shape.
• the circumferential teeth 20 have a cross-section with a substantially rectangular trapezoid shape.
• the cross-section with a trapezoid shape is defined, on the lateral surface 17, by a straight segment 21, substantially parallel to the axis of rotation X, and by an oblique segment 22 connected to the straight segment 21 and inclined with respect to the latter in the direction of the cusp 14.
• the ring 10 is axial symmetrical around the axis of rotation.
• the straight segments 21 and the oblique segments 22, in an axial symmetrical development of the ring 10 around the axis X respectively define the cylindrical annular surfaces 18 and the conical annular surfaces 19.
• the lateral surface 17, in an axial symmetrical development of the ring 10 around the axis of rotation X defines a cone.
• the sides of the triangular cross-section of the ring 10, defining the lateral surfaces 17 in axial symmetry, have a saw tooth-type development, in particular with trapezoidal teeth, given by the alternation of straight segments 21 and oblique segments 22.
• the lateral surfaces 17 of one ring 10 have the same number of circumferential teeth 20.
• the lateral surfaces 17 of one ring 10 have a symmetrical disposition of the circumferential teeth 20 with respect to the lying plane of the cusp 14.
• the lateral surfaces 17 of one ring 10 have circumferential teeth 20 that have the same sizes.
• the lateral surfaces 17 of one ring 10 can have circumferential teeth 20 with increasing or decreasing sizes from the base surfaces 15 to the cusp 14.
• the straight segments 21 can have small inclinations, positive or negative, comprised between 0° and 15° with respect to the axis of rotation X.
• the straight segments 21 have a width, in the direction parallel to the axis of rotation X, which varies according to the number of circumferential teeth 20 provided for each lateral surface 17.
• the width of the straight segments 21 can be comprised between about 0.6 mm and about 4 mm, preferably between 1 mm and 2 mm, advantageously around 1 mm.
• the straight segments 21 can have a variable width, increasing or decreasing, along the lateral surface 17 of the ring 10.
• the cusp 14 also has a variable width according to the type of selection to be obtained.
• the width of the cusp 14 can be comprised between 0.8 and 1.2 mm, advantageously around 1 mm.
• the width of the oblique segment 22 can be variable according to the number of circumferential teeth 20.
• the width of the oblique segment 22, parallel to the axis of rotation X can be comprised between 1 and 5 mm, preferably between 2 mm and 3 mm, advantageously around 2 mm.
• the oblique segments 22 can have a variable width, increasing or decreasing, along the lateral surface 17 of the ring 10.
• the oblique segment 22 is inclined by an angle a comprised between 40° and 75°, advantageously comprised between 50° and 70°, with respect to the straight segment 21 in the direction of the cusp 14. In this way, a sequence of oblique 22 and straight segments 21 can be easily obtained on the lateral surface 17, following the development of the latter starting from the base surface 15 until reaching the cusp 14.
• each ring 10 can have a number of circumferential teeth 20 comprised between two and ten, preferably between four and six. This choice depends on the type of selection to be carried out.
• the last circumferential tooth 20 ending in the cusp 14 is also counted. Consequently, the number of circumferential teeth 20 is equal to the number of the repetitions of conical annular surfaces 19 along a lateral surface 17 of one ring 10.
• Each ring 10 can be made in a single piece.
• each ring 10 can be made of at least two distinct annular elements 24.
• the cross-section, with respect to the axis of rotation X, of such annular elements 24 can be in the shape of a right-angled triangle so as to form a substantially isosceles triangle when installed adjacent to form a ring 10.
• a roll 11 is provided with a respective drive shaft 12 rotating around the axis of rotation X.
• a roll 11 comprises a plurality of rings 10 disposed adjacent and in sequence along a drive shaft 12 in order to define a selection profile of the roll 11 given by the alternation of cusps 14 and grooves 16.
• the base surface 15 of one ring 10 adjacent to the base surface 15 of the adjacent ring 10 defines the groove 16 of the roll 11.
• the plurality of rings 10 defines a selection profile of the roll 11 with respectively positive and negative V shapes which follow one another.
• the roll 11 can be made in a single body providing a plurality of rings 10 integrally constrained to each other.
• a machine 13 to select incoherent material in the form of chips and to eliminate inert materials comprises a plurality of rolls 11 disposed adjacent so that the cusps 14 of one roll 11 co-penetrate into the grooves 16 of the adjacent roll 11, defining a discharge gap 26 with a substantially zig-zag development.
• discharge gap 26 we mean the passage gap obtained from the distance between the lateral surfaces 17 of two adjacent rolls 11. Even more particularly, by discharge gap 26 we mean the passage gap obtained from the distance between the oblique segments 22 of the lateral surfaces 17 of two adjacent rolls 11.
• the machine 13 comprises a plurality of rolls 11 rotating in the same direction and disposed adjacent to each other, in order to define a progressive succession of discharge gaps 26 of desired and adjustable value.
• the discharge gap 26 has a serrated or jagged pattern given by the contrapositioning of respective conical annular surfaces 19 and cylindrical annular surfaces 18 of adjacent rolls 11.
• the adjacent rolls 11, rotating in the same direction, define a selection plane on which the material to be selected is fed.
• the material to be selected advances on said rolls 11 in a direction of feed F.
• the machine 13 comprises a plurality of adjacent drive shafts 12, or at least two adjacent drive shafts 12.
• Each drive shaft 12 is configured to rotate around its own axis of rotation X coaxial to the drive shaft 12 itself.
• each drive shaft 12 can be configured to rotate at different rotation speeds in a manner correlated to the subsequent drive shafts 12.
• the rolls 11 of the machine 13 can be disposed adjacent horizontally so that the respective axes of rotation X are parallel and aligned with each other.
• the rolls 11 of the machine 13 can be disposed adjacent horizontally so that the respective axes of rotation X are parallel and offset with respect to each other.
• the discharge gap 26 can be defined by a series of discharge areas A1 with a substantially parallelogram shape provided consecutive, adjacent and offset with respect to each other.
• the discharge gap 26 since it has a serrated development, can provide, in the direction of feed F of the material to be selected, at least two different amplitudes, a first amplitude G1 and a second amplitude G2. Each of these amplitudes G1 and G2 identifies a respective discharge area, indicated by way of example and respectively with A1 and A2. Such discharge areas A1 and A2 are repeated cyclically along the discharge gap 26. The discharge areas A1 and A2 therefore have different sizes, since they are defined by different amplitudes G1 and G2.
• these discharge areas Al, A2 also allow a selection according to shape as well as size.
• a first discharge area Al can be in the shape of an elongated parallelogram defined by the contrapositioning of two oblique segments 22 facing each other and belonging respectively to two opposite rolls 11.
• the distance between the two oblique segments 22, facing each other and belonging respectively to two opposite rolls 11, identifies the first amplitude G1 of the discharge gap 26.
• a second selection area A2 can have a square, rectangular or parallelogram shape of smaller sizes than the first discharge area Al.
• the second area A2 can be defined by the contrapositioning of two oblique segments 22 facing each other and offset consecutively with respect to each other and belonging respectively to two opposite rolls 11.
• the distance between the two oblique segments 22, facing each other and offset consecutively with respect to each other and belonging respectively to two opposite rolls 11, identifies the second amplitude G2 of the discharge gap 26.
• the ratio between the second amplitude G2 and the first amplitude G1 can be comprised between 1.5 and 2, preferably between 1.6 and 1.8.
• the second selection area A2 is favorable to the passage of small-sized inert polluting material with a generally round or square shape, while the parallelogram-shaped selection area A1 is more favorable to the passage of wood material with a generally elongated shape.
• one or more of the conical annular surfaces 19 can be knurled so as to better direct and accompany the incoherent material to be selected toward the discharge gap 26.
• the cusp 14 can have a plurality of hollows 23 disposed circumferentially to define an indentation that facilitates the drawing and removal of the material in the zone of cooperation between the grooves 16 of one roll 11 and the cusps 14 of the adjacent roll 11.
• such rolls 11 can all be identical to each other or progressively differentiated continuously or in groups in the direction of feed F according to the selection level to be reached.
• the machine 13 comprises two or more groups of adjacent rolls 11 wherein one group of rolls 11 comprises at least two rolls 11 adjacent and identical to each other.
• the machine 13 can comprise groups of rolls 11 all identical to each other.
• the machine 13 can provide groups of rolls 11 with different rotation speeds to each other.
• the machine 13 can provide groups of rolls 11 each of which have rings 10 that have lateral surfaces 17 with a number of circumferential teeth 20 different from the subsequent group of adjacent rolls. In this way, it is possible to vary the amplitude Gl, G2 of the discharge gap 26, as well as by possibly acting on the distance between one roll 11 and the next, also by varying the number of circumferential teeth 20 provided in the direction of feed F of the material to be selected.
• the amplitude Gl, G2 of the discharge gap 26 is gradually increased in the sense of the direction of feed F of the material to be selected, so as to select particles of material with gradually increasing sizes.
• a discharge gap 26 which is gradually increasing starting from a discharge gap with minimum amplitude Gl comprised between 0.5 and 1.5 mm up to a discharge gap with maximum amplitude G1 comprised between 4 mm and 12 mm, or as an extreme case also 16 mm.
• the minimum amplitude G2 can be comprised between 0.75 mm and 3 mm and the maximum amplitude G2 can be comprised between about 6 mm and about 24 mm.
• rings 10 are shown with six circumferential teeth 20 and, in fig. 7, rings 10 are shown with four circumferential teeth 20.
• the rolls 11 with lateral surfaces 17 with six circumferential teeth 20 can, advantageously, select materials with sizes comprised between 0.5 mm and 1.5 mm allowing to eliminate inert materials such as pebbles and sand which, with the current technology, are difficult to identify and, at the same time, reducing the losses of wood material in an attempt to eliminate these inert materials.
• the invention therefore allows to obtain a high degree of cleanliness of the incoherent wood material eliminating fractions of inert materials even below the order of a millimeter.
• wood material mixed with inert materials discarded in said selection can undergo another cleaning or screening, for example by means of flotation, in order to recover as much wood material as possible and/or it can be re-used with an energy function, that is, for example, it can be burned in special burners.
• This solution allows to make the most of the incoherent material to be selected, also re-using the discarded material so as to optimize the screening of the chips and reduce waste of energy and material.
• the rolls 11 with rings 10 that have lateral surfaces 17 with four circumferential teeth 20 can select materials with sizes comprised between 1.6 mm and 3 mm, preferably between 1.6 mm and 2.8 mm.
• such rolls 11 with lateral surfaces 17 with four circumferential teeth 20 located in sequence, in the direction of feed F, with rolls 11 with rings 10 with lateral surfaces 17 with six circumferential teeth 20, allow to obtain a more thorough selection of the wood material.
• the discharge gap 26 between adjacent rolls 11 can be adjusted by further acting on the distance between the rolls 11 themselves, bringing them closer or further away from each other.
• discharge gap 26 can be adjusted by acting on the distance between the rolls 11 in cooperation with the choice of the number and size of the circumferential teeth 20 to be provided on each lateral surface 17.
• the zig-zag profile of the rolls 11 with a serrated or jagged surface development also allows cooperation between rolls 11 with rings 10 that have different numbers of circumferential teeth 20, allowing to obtain a continuous and gradual selection of the incoherent material in the form of chips, without adding additional components, limiting the bulk of the machine 13 and reducing the respective energy consumption.
• the invention compared to the state of the art also allows to use fewer rolls 11 to process the same amount of incoherent material, guaranteeing high efficiency of the machine 13 and a consequent lower operating cost thereof.
• fig. 6 shows the cooperation between one roll 11 with rings 10 having lateral surfaces 17 with six circumferential teeth 20 and one roll 11 with rings 10 having lateral surfaces 17 with four circumferential teeth 20 in the passage, in the direction of feed F, from the selection of material with size 0.5 mm - 1.5 mm to the selection of material with size 1.6 - 3 mm.
• one or more intermediate selections could be provided in the machine 13 to improve the selection of incoherent material by acting on the number of circumferential teeth 20 and on their disposition.
• the choice of the number of circumferential teeth 20 on a lateral surface 17 of the rings 10 of each roll 11, and the choice of the number of different types of consecutive selections to be obtained depends on the final use of the wood. For example, in the case of MDF panels it is necessary to obtain chips with a high degree of cleanliness from inert materials, or polluting materials in general, in order to obtain a superior quality panel.
• the machine 13 in accordance with some embodiments described here, can be used both to select virgin or fresh incoherent wood material and also to select recycled incoherent wood material coming from production waste and/or post-production recovered material.
• machine 13 in accordance with some embodiments described here, can be used downstream and/or upstream of further screening steps.
• the machine 13, in accordance with some embodiments described here can be used in combination with known screening techniques and technologies, for example with blowing devices (not shown) in order to improve the selection.
• the machine 13, in accordance with some embodiments described here, can be preferentially used to select wood in its wet phase, that is, with a high percentage of moisture, for example even up to 100% moisture.
• this machine 10 can also be used in the dry phase, that is, with wood with a low percentage of moisture even lower than 10%.

Landscapes

• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Mechanical Engineering (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Orthopedics, Nursing, And Contraception (AREA)
• Adornments (AREA)
• Supplying Of Containers To The Packaging Station (AREA)
• Combined Means For Separation Of Solids (AREA)
• Crushing And Grinding (AREA)

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Citations (6)

• 2019
  • 2019-08-09 IT IT102019000014487A patent/IT201900014487A1/it unknown
• 2020
  • 2020-08-04 PT PT207719287T patent/PT4010128T/pt unknown
  • 2020-08-04 EP EP20771928.7A patent/EP4010128B1/en active Active
  • 2020-08-04 WO PCT/IT2020/050199 patent/WO2021028955A1/en active Search and Examination
  • 2020-08-04 ES ES20771928T patent/ES2961410T3/es active Active

Patent Citations (6)

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