Disc screen for separating solid materials

Abstract

To provide a disk screen having no defects caused by the twisting of a filamentous element around a disk and a rotary shaft.SOLUTION: A disk screen for separating a solid residue is provided with a plurality of rotary shafts 3 and a plurality of disks 4 fixed to the rotary shaft 3. To prevent the possibility of the tangling and interference of a subsequent material at the rotary shaft 3, thrust blades 12 having a curved section adapted so that a component of a material to be sorted (concretely, a lightweight material or a filament material) is blocked, are arranged at side surfaces 4A, 4B of the disks 4 for discharging the material to the outside of a space I between the disks 4.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The invention relates to a disc screen for separating solid materials according to the preamble of independent claim 1.

[0002] The disc screen of the present invention is intended to be employed to separate various types of solid materials such as municipal solid waste, inert matter from rivers, generation of the organic fraction during separation of waste collections, compost (for its refining), recycled wood, biomass, inert matter, demolition materials, land drainage materials as well as trash materials, glass, plastic, scrap metal, and still other materials.

[0003] It is therefore intended that in industrial sectors dealing with solid residues, a disc screen according to the invention can be inserted and advantageously installed downstream of a crushing or grinding plant for said residues. [Background technology]

[0004] Hereinafter, the term "residue" will be used to refer interchangeably to any one solid material that is required to be separated into components based on size or mass for the sake of simplicity of explanation.

[0005] Several different devices are known on the market, employing different construction and operating principles, intended to be employed for separating solid residues in several fields of application. Some examples of such devices include disc screens, mesh screens, screw screens, drum screens, acceleration separators, fluidized bed separators, electrostatic separators, magnetic separators, and even others.

[0006] In particular, the disc screen usually comprises a support structure which rotatably supports a number of successive, equally spaced shafts which are mounted on the disc screen and which are parallel to one another and rotate in the same rotational sense. To allow for the interleaving of the discs mounted on successive shafts, groups of discs separated from one another by a distance at least equal to, and preferably greater than, the thickness of a single disc are axially fixed to each shaft, so that each disc of any one shaft is interleaved between two discs of the adjacent front and rear shafts.

[0007] In the technical field of the present invention, one measurement that distinguishes the properties of disc screens is the screening surface, which is defined as the area of ​​the opening bounded between the disc and the rotating shaft, and thus indicates the size of the residue that is separated from the screen and falls by gravity below the screening surface.

[0008] A disc screen mounted on the periphery of each shaft and provided with idle sleeves interposed between the discs, the function of which is to prevent or at least limit disturbance of the screening surface, is known from EP 1 106 264 A1.

[0009] More specifically, each sleeve is mounted axially on the shaft between two discs with a gap adapted to allow the sleeve to rotate freely in an idle manner on the shaft or on a tubular body provided on the outside of the shaft.

[0010] In operation, a filamentary element which may be twisted outwards about the idle sleeve until it impinges on a disc mounted on a successive shaft will not impair the operation of the screen, nor will each sleeve idling relative to the shaft on which it is mounted interfere with the rotation of the shaft itself, without the filamentary element being able to determine the cessation of operation of the screen.

[0011] The main drawback of this solution lies in the fact that disc screens with idle sleeves of the known type allow small sized matter such as sand, dust etc. to be inserted in the gap that exists between the idle sleeve and the disc that fits on the shaft, so as to create a mechanical connection between the rotating shaft and the sleeve itself, driving the sleeve in rotation and disrupting its anti-twisting action.

[0012] In order to overcome such drawbacks, a screen of the above mentioned kind is known from EP 3 085 462 A1, in which an idle sleeve is provided with two flanges intended to be inserted into suitable grooves made on the lateral faces of the disc, so as to prevent the accumulation of such materials and, in any case, to create a gap between the sleeve and the disc, allowing the sleeve to rotate freely relative to the disc and preventing problems with twisting.

[0013] However, this type of screen also suffers from several drawbacks, including poor performance in separating plastic materials of different sizes (particularly plastic materials such as shopping bags, packages, bags, etc.).

[0014] More specifically, some types of plastic materials (e.g., the aforementioned materials of shopping bags, packages, bags), as well as any soft sheet-like plastic material, may be fitted between the discs of the screen, causing problems with the operation of the screen and increasing maintenance time and costs.

[0015] Disc screens provided with so-called "star-shaped" discs provided on their outer section with one or more projecting tips are also known from patent documents GB 2 072 049 and US 3 870 627. In particular, the screen described in GB 2 072 049 provides that some discs are provided with their projecting tips along their outer edges and with enlarged areas between the discs to prevent the ingress of stones or other objects.

[0016] Thus, the disc screens for separating solid materials known in the art have demonstrated that they are not without drawbacks. Among them, there are those that have a low ability to direct the aforementioned type of residue in the forward direction. Thus, such residue can be sorted in an undesirable way, or it can easily be inserted between the discs, or it can be twisted around the discs and the rotating shaft, causing the screen to stop for its manual removal. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] European Patent Application Publication No. 1106264 [Patent Document 2] European Patent Application Publication No. 3085462 [Patent Document 3] GB Patent Application Publication No. 2072049 [Patent Document 4] U.S. Pat. No. 3,870,627 Summary of the Invention [Problem to be solved by the invention]

[0018] In this context, the problem inherent in the present invention is therefore to eliminate the problems of the aforementioned prior art by providing a disc screen for separating solid materials, which makes it possible to eliminate or significantly reduce the drawbacks resulting from the twisting of the thread-like elements around the disc and the rotating shaft, in particular by preventing repetitive maintenance operations.

[0019] It is a further object of the present invention to provide a disc screen for separating solid materials that has high performance separation of plastic materials having different sizes.

[0020] It is a further object of the present invention to provide a disc screen for separating solid materials that is generally reliable in operation over time.

[0021] It is a further object of the present invention to provide a disc screen for separating solid materials that is inexpensive to manufacture. [Means for solving the problem]

[0022] The technical characteristics of the findings according to the above-mentioned objectives are clearly seen in the contents of the "claims" reported below, and their advantages will become more apparent in the following detailed description, with reference to the attached figures, which represent some merely illustrative and non-limiting embodiments of the present invention. [Brief description of the drawings]

[0023] [Figure 1] 1 shows a perspective schematic view of a disc screen for separating solid materials according to the present invention; [Diagram 2] 2 shows an enlarged detail of the disc screen of FIG. 1 in plan view for several rotating shafts with multiple discs mounted on the rotating shafts. [Diagram 3] FIG. 3 shows a detail of FIG. 2 in a side view. [Figure 4] FIG. 1 shows a view of a longitudinal section of one of the rotating shafts of the inventive disc screen according to a first embodiment of the invention. [Diagram 5] FIG. 2 shows a side view of one of the screen discs according to the first embodiment of the present invention. [Figure 6] FIG. 6 shows a perspective view of the disk of FIG. 5. [Figure 7] FIG. 7 shows a perspective view of a detail of the disk shown in FIG. 6 with respect to the thrust vanes of the disk itself. [Figure 8] FIG. 2 shows a perspective view of one of the discs of the screen of the invention according to the second embodiment described above of the invention; [Figure 9] FIG. 9 shows a perspective view of the blocking element of the disc shown in FIG. 8. [Figure 10]FIG. 3 shows a perspective view of the disc screen of the invention with respect to several rotating shafts according to a third embodiment of the invention. [Figure 11] 11 shows a plan view of a portion of the rotating shaft of FIG. 10. [Figure 12] 12 shows a cross-sectional view of the rotating shaft of FIG. 11 according to line XII-XII of FIG. 11 itself. [Figure 13] 13 shows an additional cross-sectional view of the rotating shaft of FIG. 11 according to line XIII-XIII of FIG. 12. [Figure 14] FIG. 13 shows a side view of one of the disks of FIG. 12. [Figure 15] FIG. 4 shows a perspective view of a disc screen of the invention with respect to several rotating shafts according to a fourth embodiment of the invention. [Figure 16] 16 shows a plan view of a portion of the rotating shaft of FIG. 15. [Figure 17] 17 shows a cross-sectional view of the rotating shaft of FIG. 16 according to line XVII-XVII of FIG. 16 itself. [Figure 18] 18 shows an additional cross-sectional view of the rotating shaft of FIG. 16 according to line XVIII-XVIII of FIG. 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] With reference to the attached figures, the reference number 1 indicates, as a whole, a disc screen for separating solid materials which is the object of the present invention.

[0025] The disc screen 1 according to the invention is adapted to be employed for separating various kinds of solid materials such as solid municipal waste, inert matter from rivers, products of the organic fraction of separated waste collections, compost (for its refining), recycled wood, biomass, inert matter, demolition materials, land drainage materials as well as garbage materials, glass, plastics, scrap metal, and further other materials.

[0026] In particular, the disc screen 1 of the invention is particularly suitable for separating plastic waste from the remaining mass of solid material.

[0027] According to the embodiment shown in the attached drawings, the disc screen 1 of the invention comprises a support structure (2) intended to abut against the ground and to extend between an entrance door and an exit door according to a forward direction A influenced by the advance of the solid material to be screened.

[0028] The disc screen 1 also comprises a number of rotating shafts 3 rotatably mounted on mutually parallel support structures 2, spaced apart from one another at a fixed interval pitch, and arranged in succession along the forward direction A.

[0029] Each of the rotating shafts 3 advantageously extends longitudinally (preferably horizontally and perpendicularly to the advancement direction A) according to its extension axis X. In particular, without departing from the scope of protection of the patent of the invention, the extension axis X of the rotating shafts 3 identifies a screening surface which is preferably horizontal (but may be inclined) according to the embodiment shown in the attached figures.

[0030] According to the invention, the disc screen 1 also comprises a number of discs 4 fixed axially in succession along the rotating shaft 3 for receiving a rotational movement from the rotating shaft 3 .

[0031] More specifically, each of the rotating shafts 3 carries a number of corresponding discs 4 (e.g. 9 or 10) arranged in succession along the extension axis X of the rotating shaft 3 itself, which are fixed (preferably fitted) to the rotating shaft 3.

[0032] The disks 4 are preferably positioned along the corresponding rotating shaft 3 spaced one from the next at a constant pitch. Each of the disks 4 is advantageously provided with an axis of rotation Y of the disks 4 which is parallel to and preferably coincides with the extension axis X of the corresponding rotating shaft 3.

[0033] In particular, as is visible, for example, in the views of Figures 2, 11 and 16, the distance between each of the discs 4 and the neighboring one is greater than the respective thickness of a single disc 4 (thickness according to the extension axis X) in order to make it possible to interpose a disc 4 mounted on a successive rotating shaft 3 according to the advancement direction A between two adjacent discs 4 mounted on the same rotating shaft 3, with at the same time a lateral gap I between each of the two discs 4 of a rotating shaft 3 and the interposed disc 4 of the successive rotating shaft 3.

[0034] For such purpose, the disks 4 mounted on each of the rotating shafts 3 are mounted offset with respect to the disks 4 mounted on successive rotating shafts 3, so that the rotating shafts can be interposed between each of the disks 4.

[0035] Specifically, the distance between the rotating shafts 3 along the forward direction A and the distance between the discs 4 along the rotation axis Y (specifically the aforementioned lateral gap I) define the screening section of the disc screen 1 and determine the maximum size (dimension) of material that will be sifted out (passing under the rotating shafts 3), while oversized material will be conveyed towards the exit door of the disc screen 1.

[0036] According to the invention, the disc screen 1 comprises drive means 5 mechanically connected to the rotating shaft 3 for actuating each of the discs 4 to rotate about their rotation axis Y in a particular rotational orientation R (represented, for example, in Figures 1, 3 and 5).

[0037] More specifically, drive means 5 are arranged for rotating each of the rotating shafts 3 about its extension axis X in the aforementioned rotational direction R in a manner such that each of the rotating shafts 3 rotates and supports a disc 4 mounted on the rotating shaft 3.

[0038] For such purpose, in particular, the disks 4 are mechanically rigidly coupled to the corresponding rotating shaft 3 in order to receive the rotational movement of the rotating shaft 3. For example, the rotating shaft 3 has a pre-formed male contour 3', in particular a polygonal shape (defined by the shape of its outer surface, in particular by its cross section), and each of the disks 4 has a pre-formed female contour 4' joined to said pre-formed male contour 3' and in particular defined by a through hole 6 adapted to receive the rotating shaft 3.

[0039] In particular, the rotation of the disc 4 in the aforementioned rotational orientation R is thus intended to determine the forward orientation of the residual material along the forward direction A from the inlet door to the outlet door of the support structure 2 of the disc screen 1, essentially in a totally conventional manner (which for this reason will not be described in detail).

[0040] For example, with reference to the particular embodiment shown in Figures 2 and 3, the drive means 5 comprises an electric motor 7 and a motion transmission means 8 mechanically connected to the electric motor 7. Such motion transmission means 8 in turn comprises a chain 9, which is preferably wound in a closed loop and engages with a pinion 10 fixed to a gear 11 fitted on the shaft of the electric motor 7 and on the rotating shaft 3, respectively.

[0041] The drive means 5 are adapted to move all of the rotating shafts 3 in the same rotational sense R in order to move the solid material to be screened from the inlet door to the outlet door of the disc screen 1, simultaneously with the rotation of the discs 4, as described above.

[0042] In particular, the disc 4 is provided with an outer section (e.g. polygonal) which is suitably shaped to facilitate advancement of the solid material along the screening surface along an advancement direction A, as will be better described herein below.

[0043] With reference to Figures 4 to 18, each of the discs 4 extends (according to the axis of rotation Y) between two opposing external lateral faces 4A and 4B which delimit the thickness of the disc 4 itself between them.

[0044] In particular, the two lateral faces 4A, 4B of each of the discs 4 are substantially perpendicular to the axis of rotation Y (preferably parallel to each other) and face oppositely relative to each other (towards the exterior of the disc 4).

[0045] Each of the lateral faces 4A, 4B is provided with an outer edge 4D, which extends around the axis of rotation Y and delimits said lateral faces 4A, 4B and advantageously surrounds said lateral faces 4A, 4B inside the outer edge 4D. The outer edge 4D preferably has a convex shape (e.g. polygonal). Each of the lateral faces 4A, 4B is advantageously provided with an inner edge 4E, which is located inside the outer edge 4D and in particular defines a through hole 6 through which the rotating shaft 3 is inserted.

[0046] According to the embodiment shown in the attached figures, each of the disks 4 is advantageously provided with a peripheral surface 4C arranged to connect the outer ends 4D of the two lateral faces 4A, 4B, preferably provided with a plurality of planes in such a manner that the disk 4 has the shape of a polygonal prism (for example with a hexagonal base). Such a shape of the disk 4 (specifically the shape of the peripheral surface 4C of the disk 4) facilitates the advancement of the solid material to be sorted during the rotation of the rotating shaft 3. In other embodiments of the invention, the disk 4 may also have an outer section with a different shape, advantageously adapted to facilitate the advancement of the residue from the entrance door to the exit door along the advancement direction A.

[0047] Suitably, each of the discs 4 is formed by a number of metal walls joined together and positioned to define the aforementioned faces / surfaces 4A, 4B, 4C of the disc 4 itself.

[0048] As is visible in the examples of Figures 2 to 4 and 11 to 18, the disc screen 1 of the invention is advantageously provided with a number of sleeves 20, interposed between a pair of continuous discs 4 (along the extension axis X of the corresponding rotating shaft 3), externally and loosely mounted on the rotating shaft 3.

[0049] Specifically, each of the sleeves 20 has a tubular body 21 extending (according to the extension axis X of the corresponding rotating shaft 3) between two opposing end edges 21', and the sleeves 20 are installed on corresponding lateral faces 4A, 4B of the two discs 4, with the sleeve 20 interposed between the end edges 21'.

[0050] Suitably, the screening section of the disc screen 1 is defined by the aforementioned lateral gap I and the distance between the peripheral surface 4C of each disc 4 of the rotating shaft 3 and the tubular body 21 of the sleeve 20 of the adjacent rotating shaft 3.

[0051] The disc screen 1 preferably comprises a plurality of spacer tubular bodies 25, each of which is mounted externally on the rotating shaft 3 and is successively interposed and abutted between the lateral faces 4A, 4B of two discs 4. Thus, specifically, the discs 4 are successively installed along the rotating shaft 3, alternating with the spacer tubular bodies 25 being pressed between successive discs 4 rotating together with the rotating shaft 3.

[0052] Suitably, the spacer tubular body 25 has a length slightly greater than the length of the sleeve 20 to allow idle rotation of the sleeve 20 .

[0053] According to the idea underlying the invention, the disk 4 comprises at least one thrust vane 12 fixed to corresponding lateral faces 4A, 4B of the disk 4 itself.

[0054] As reported in the examples described below, one or both of the lateral faces 4A, 4B of the disks 4 can be provided with one or more thrust vanes 12. In addition, the thrust vanes 12 can be suitably pre-positioned on all disks 4 of the screen 1 or only on some subset of the disks 4 (for example on the disks 4 of only a part of the rotating shaft 3). As described in detail herein below, the aforementioned thrust vanes 12 according to the invention are adapted to intercept components of solid material (particularly light material components such as filamentous plastic components) penetrating between the lateral gaps I of the disks 4 and to push the said components out of the lateral gaps I following the corresponding rotation of the disks 4, specifically pushing the material in the forward direction A towards the exit door of the disk screen 1 in a manner that prevents interference or entanglement that may hinder the normal operation of the disk screen 1.

[0055] Suitably, following the rotation of the corresponding disc 4, the thrust vanes 12 are subjected to the generation of centrifugal air vortices which help to maintain the light material components lifted from the rotating shaft 3 and further reduce the risk of jamming or entanglement.

[0056] In particular, the required thrust vane 12 arrangement makes it possible to counter the drawbacks presented by the prior art, preventing residues with sizes different from those to be screened and filamentous residues, which may potentially be twisted around the rotating shaft 3, from moving away from the lateral gaps I between the discs 4 and being made to proceed in the forward direction A, thus reducing the maintenance required by the disc screen 1 and increasing the screening efficiency.

[0057] More specifically, referring to the examples of Figures 5 to 18, the thrust vanes 12 protrude from the corresponding side surfaces 4A, 4B and extend (in the direction of the rotation axis Y) through a lateral gap I between the side surfaces 4A, 4B and the discs 4 facing the corresponding side surfaces 4A, 4B.

[0058] In particular, the thrust vanes 12 extend beyond the lateral edges of the shaped plate of the peripheral surface 4C of the disc 4 and protrude from the corresponding lateral faces 4A, 4B.

[0059] According to the invention, the thrust vanes 12 are provided with front faces 13 which are oriented according to the rotational orientation R of the disc 4 when the disc 4 is actuated in rotation by the drive means 5 in such a manner as to block components of solid material penetrating into the corresponding lateral gaps I.

[0060] More specifically, the front face 13 of the thrust vane 12 extends between an inner portion 14 (preferably the front face) and an outer portion 15 (preferably the rear face) which is further away from the rotation axis Y of the disc 4 relative to the inner portion 14.

[0061] Suitably, the thrust vanes 12 (specifically the front faces 13 thereof) extend at least partially (and preferably completely) inside the corresponding lateral faces 4A, 4B inside the outer edges 4D of the lateral faces 4A, 4B themselves. Thus, the thrust vanes 12 (specifically the front faces 13 thereof) extend into the lateral gaps I delimited between the corresponding and adjacent disks 4.

[0062] Such a shape of the front face 13 of the thrust vane 12 enables the front face 13 to intercept components of solid material which, following the rotation of the discs 4, enter the lateral gap I and convey said solid material towards its own outer part 15, thus pushing said components of solid material away from the axis of rotation Y of the discs 4 and thus forcing said solid material out of the lateral gap I between the discs 4.

[0063] Suitably, the thrust vanes 12 (which extend inside the corresponding lateral faces 4A, 4B of the discs 4 and are thus permanently inserted inside the lateral gap I between the discs 4) are also able, following the rotation of the discs 4, to intercept solid material that may have already penetrated inside the lateral gap I itself and expel said solid material from the lateral gap I.

[0064] In particular, the inner portions 14 of the thrust vanes 12 are located in a first zone of the corresponding lateral faces 4A, 4B of the disc 4 that are radially closer to the rotation axis Y, while the outer portions 15 of the thrust vanes 12 are located in a second zone of the corresponding lateral faces 4A, 4B (preferably on the outer section of the disc 4) that are located radially further away from the rotation axis Y.

[0065] The front face 13 of the thrust vane 12 advantageously has a longitudinal section which extends, in said rotational direction R, from the outer part 15 to the inner part 14 when moving close to the axis of rotation Y. In particular, said longitudinal section is defined by a cut-off of the front face 13 with a surface perpendicular to the axis of rotation Y of the disc 4. Suitably, said longitudinal section of the front face 13 of the thrust vane 12 extends in a certain circular sector around the axis of rotation Y of the disc 4 and is preferably substantially parallel to the corresponding lateral faces 4A, 4B of the disc 4 itself.

[0066] A longitudinal section of the front surface 13 of the thrust vane 12 extends inside the corresponding lateral surface 4A, 4B of the disk 4. More precisely, said longitudinal section is located at least partially inside the outer edge 4D of the corresponding lateral surface 4A, 4B. In particular, said longitudinal section is entirely located inside the outer edge 4D of the corresponding lateral surface 4A, 4B, and at most an outer portion 15 of the thrust vane 12 may be located at (e.g. substantially flush with) said outer edge 4D.

[0067] Preferably, the thrust vanes 12 (specifically the longitudinal section of their front faces 13) do not protrude outside the outer edges 4D of the corresponding lateral faces 4A, 4B.

[0068] In operation, when the disk 4 rotates in the direction of rotation R, the inner portion 14 of the front face 13 of the thrust vane 12 comes in front of the outer portion 15. Thus, the solid material is blocked by the inner portion 14 of the thrust vane 12 and is pushed by a certain extension of the longitudinal section of the front face 13 outwards of the lateral gap I and in the forward direction.

[0069] The centrifugal vortex generated by the thrust vanes 12 of the rotating discs 4 further provides the advantage of facilitating the maintenance of light material outside the lateral gaps I between the discs 4 .

[0070] The longitudinal section of the front surface 13 has a convex shape, preferably a curved shape. Such a particular shape of the longitudinal section of the front surface 13 further facilitates a thrust action of the front surface 13 on the component of the remaining material, carrying said component of the remaining material towards its outer portion 15 and thus outside the lateral gap I, without such material remaining blocked on the front surface 13 itself.

[0071] Preferably, referring to the examples of Figures 5 and 14, a longitudinal section of the front surface 13 of the thrust vane 12 is bounded by a dotted line at an inclination angle α (preferably an obtuse angle) greater than 90° with respect to a circumference C, the circumference C having the centre of the axis of rotation Y of the disc 4 and passing through said point of the longitudinal section.

[0072] Specifically, said angle α extends from a circumferential tangent C to a point incident on the longitudinal section towards the outer portion 15 of the front surface 13 to a tangent to the longitudinal section at said point of incidence.

[0073] Such an inclination angle α of the longitudinal section makes it possible that during rotation of the discs 4 in the direction of rotation R, the thrust vanes 12 move the material component outside the lateral gap I between the discs 4 so as to penetrate into the lateral gap I and at the same time advance the material component in a forward direction along the forward direction A.

[0074] Preferably, the thrust vanes 12 are provided with a rear face 17 (eg with a concave shape) facing away relative to the front face 13 .

[0075] Specifically, when the disk 4 rotates in the rotational direction R, the leading surface 13 of the thrust vane 12 comes in front of the trailing surface 17 .

[0076] Suitably, the leading surface 13 and the trailing surface 17 delimit a thickness S of the thrust vane 12 therebetween.

[0077] The thrust vane 12 is also advantageously provided with an inner side 18 facing towards and fixed to the corresponding lateral side 4A, 4B of the disc 4, and an outer side 19 facing oppositely to the inner side 18 and facing the lateral gap I between the discs 4. Suitably, the inner side 18 and the outer side 19 delimit between them a width H of the thrust vane 12 (along the axis of rotation Y of the discs 4), which width H in particular defines the distance by which the thrust vane 12 projects beyond the corresponding lateral side 4A, 4B of the discs 4.

[0078] The front faces 13 of the thrust vanes 12 are advantageously substantially perpendicular to the corresponding lateral faces 4A, 4B of the disc 4, in a preferred manner in which the thrust vanes 12 protrude from the corresponding lateral faces 4A, 4B of the disc 4 perpendicular to the aforementioned lateral faces 4A, 4B with the above-mentioned width H.

[0079] The thrust vanes 12 advantageously extend in an elongated (particularly curved) shape from an inner portion 14 to an outer portion 15 of the forward facing surface 13 .

[0080] The thrust vanes 12 preferably extend longitudinally between a forward end 16' (located on the inner portion 14 of the forward surface 13) towards the front with respect to the direction of rotation R of the disk 4, and an opposite aft end 16'' (located on the outer portion 15 of the forward surface 13).

[0081] At least a portion of the front surface 13 of the thrust vane 12 is preferably located separate from the outer edge 4D of the lateral surface 4A, 4B on the inside of said outer edge 4D. In particular, an inner portion 14 of the front surface 13 of the thrust vane 12 is located on the lateral surface 4A, 4B, spaced apart from the outer edge 4D of the corresponding lateral surface 4A, 4B.

[0082] Suitably, the thrust vanes 12 have a rigid shape and are made, for example, from a metal material, a plastic material, PVC, or another material.

[0083] In particular, the thrust vanes 12 are fixed to the corresponding lateral faces 4A, 4B of the disc 4, for example by welding or screw means, or the thrust vanes 12 can be made of a single body with the corresponding lateral faces 4A, 4B of the disc 4, for example by casting.

[0084] According to the embodiment shown in the accompanying drawings, the thrust vane 12 is made of a single body. Otherwise, the thrust vane 12 can be made of a number of separate parts which are continuous with respect to each other, interconnected and / or fixed to corresponding lateral faces 4A, 4B of the disk 4.

[0085] According to the exemplary embodiment shown in Figures 4 to 9, the longitudinal extension of the thrust vane 12 terminates at its free forward end 16'.

[0086] Specifically, the thrust vane 12 has a thickness S (defined between the leading face 13 and the trailing face 17) that tapers toward an inner portion 14 of the leading face 13 (i.e., toward a leading end 16' of the thrust vane 12).

[0087] The leading ends 16 ′ of the thrust vanes 12 have a pointed shape, which advantageously faces forward with respect to the direction of rotation R of the disk 4 .

[0088] In operation, the pointed leading edge 16' located on the inner portion of the front face 13 first blocks components of the residual material penetrating into the lateral gap I and facilitates the penetration of the thrust vane between the residual material in order to more easily remove the residual material.

[0089] The rear face 17 of the thrust vane 12 is advantageously joined to the forward face 13 at the forward end 16 ′ in such a manner that the thickness S of the thrust vane 12 at the forward end 16 ′ tapers towards the inner portion 14 of the forward face 13 .

[0090] In accordance with a first embodiment of the present invention shown in Figures 6 and 7, the thrust vane 12 extends from an inner portion 14 to an outer portion 15 with a substantially constant width H (defined between an inner side 18 and an outer side 19).

[0091] In particular, according to said first embodiment, the pointed leading end 16 ′ of the thrust vane 12 is preferably straight, in particular having a straight cutter parallel to the axis of rotation Y of the disc 4 .

[0092] According to a second embodiment of the invention shown in Figures 8 and 9, the thrust vane 12 has a width H that tapers towards the inner portion 14 of the forward face 13 (specifically at the forward end 16').

[0093] More specifically, the outer side 19 of the thrust vane 12 is joined to the inner side 18 at the forward end 16 ′ in a manner such that at the forward end 16 ′, the thrust vane 12 has a width H that tapers toward the inner portion 14 of the forward face 13 .

[0094] Specifically, according to this second embodiment, the leading end 16' of the thrust vane 12 has a point-shaped cutter.

[0095] According to the embodiment shown in FIG. 4, each of the idle sleeves 20 of the disc screen is provided with two annular flanges 22, each of which is fixed to a corresponding end edge 21' of the tubular body 21 of the sleeve 20 itself and faces a corresponding lateral face 4A, 4B of the disc 4.

[0096] Each of the lateral faces 4A, 4B of the disc 4 preferably has a circular (coaxial with the axis of rotation Y) central recess 23 within which the corresponding annular flange 22 of the sleeve 20 is advantageously inserted substantially sized with a minimum clearance allowing rotation of the annular flange 22 within the corresponding central recess 23. In particular, the central recess 23 is surrounded by an annular shoulder 24 extending around the outer edge of the corresponding annular flange 22, substantially perpendicular to the lateral faces 4A, 4B of the disc 4.

[0097] An inner portion 14 of the forward face 13 of each of the thrust vanes 12 (preferably the forward end 16 ′ of the thrust vane 12 ) is advantageously located in (and more particularly in close proximity to) the sleeve 20 .

[0098] With reference to the embodiment shown in FIG. 4, the inner portion 14 of each of the forward faces 13 of the thrust vanes 12 is mounted to an annular flange 22 of the sleeve 20, preferably adjacent to an annular shoulder 24 of a central recess 23 in the corresponding lateral face 4A, 4B of the disc 4.

[0099] Naturally, the thrust vanes 12 according to the first and second embodiments described above can also be pre-arranged in the disc screen 1 in which the sleeve 20 does not have an annular flange 22 and / or the lateral faces 4A, 4B of the disc 4 do not have a central recess 23. For example, in a variant of the embodiment in which the sleeve 20 does not have an annular flange 22, the inner portion 14 of the front face 13 of each of the thrust vanes 12 is placed in the tubular body 21 of the sleeve 20 (specifically adjacent to the terminal edge 21' of the tubular body 21 itself).

[0100] According to a further embodiment variant, the disc screen 1 is not provided with the aforementioned sleeve 20 and the front end 16 ′ of the thrust vanes 12 is positioned on a corresponding rotating shaft 3 or spacer tubular body 25 .

[0101] According to the invention, the outer portion 15 of the front face 13 of the thrust vane 12 is advantageously positioned at the outer edge 4D of the corresponding lateral face 4A, 4B in a manner that facilitates the discharge of residual material outside the lateral gap I between the disks 4.

[0102] The outer portion 15 of the front surface 13 of the thrust vane 12 advantageously substantially abuts the outer edges 4D of the lateral surfaces 4A, 4B, in particular to avoid the formation of cavities in which the material to be sorted may accumulate.

[0103] According to the embodiment shown in figures 10 to 18, the disc 4 advantageously comprises at least one central ring 26 fixed to at least one of the two lateral faces 4A, 4B of the disc 4 itself.

[0104] Such a central ring 26 extends protruding from the corresponding lateral face 4A, 4B and is mounted around the corresponding rotating shaft 3 (on which the corresponding disc 4 is mounted).

[0105] In particular, each of the central rings 26 is provided with an inner section 27 (preferably with a circular shape) defining a through opening 28 through which the rotating shaft 3 intersects, and an outer section 29 which defines, relative to the inner section 27, the thickness of the central ring 26.

[0106] Suitably, the central ring 26 is made from a rigid material (such as metal, plastic material, PVC or other material) and is fixed to the lateral faces 4A, 4B of the disc 4 (or even made of a single body with the lateral faces 4a, 4B), for example by welding or screw means.

[0107] The terminal edge 21' of the tubular body 21 of the idle sleeve 20 is advantageously inserted inside a through opening 28 of a central ring 26 fixed to the corresponding lateral faces 4A, 4B of the corresponding disc 4.

[0108] Specifically, the terminal edge 21' of the sleeve 20 is inserted into a through opening 28 of the central ring 26 that is substantially sized to fit the inner section 27 of the central ring 26, with a certain gap (e.g., 2-3 mm) between the inner section 27 of the central ring 26 and the terminal edge 21' of the sleeve 20 that allows idle rotation of the sleeve 20.

[0109] Such an arrangement of the terminal edge 21' of the sleeve 20 in the central ring 26 makes it possible to protect the zone in which material (e.g., granular or filamentary) may be inserted between the sleeve 20 and the disc 4, resulting in an undesirable connection between these two elements that would interfere with the idle rotation of the sleeve 20 relative to the rotating shaft 3.

[0110] The central ring 26 advantageously connects to the thrust vanes 12 at least at the forward ends 16 of the thrust vanes 12 themselves.

[0111] The inner portions 14 of the forward faces 13 of the thrust vanes 12 are preferably connected to the outer sections 29 of the central ring 26 without forming corners or grooves that could potentially accumulate material, and specifically, are connected to each other continuously (e.g., uninterrupted).

[0112] The outer section 29 of the center ring 26 preferably extends from a point of contact with the leading end 16' of the thrust vane 12 such that the inner portion 14 of the leading surface 13 of the thrust vane 12 (specifically, with a curved shape) is continuous.

[0113] In operation, the configuration of the thrust vanes 12 connected to the central ring 26 allows such elements to act synergistically to prevent material entering the lateral gap I between the discs 4 from penetrating deeper into the gap I, thus preventing such material from affecting the rotating shaft 3 (which benefits the sleeve 20) and facilitating the ejection of that material.

[0114] The central ring 26 offers the advantage of having a width H' which is smaller than the width H of the thrust vanes 12, so that the lateral gap I between the discs 4, and therefore the screening section of the disc screen 1, does not vary significantly.

[0115] More specifically, the central ring 26 extends from the corresponding lateral faces 4A, 4B of the disc 4 with a width H' (following a direction parallel to the elongation axis X) that is smaller than the width H with which the thrust vanes 12 extend from the corresponding lateral faces 4A, 4B.

[0116] According to the example shown in Figures 10 to 18, two thrust vanes 12 are provided which are advantageously connected to a corresponding central ring 26. Naturally, without departing from the scope of protection of the patent of the invention, also only one thrust vane 12 or more than two thrust vanes 12 (for example three or six) can be provided and associated with a corresponding central ring 26.

[0117] The central ring 26 offers the advantage that it is made from several parts (for example two) separate from each other, preferably connected and joined to each other, in particular such an arrangement makes it possible to mount the central ring 26 without having to remove the disc 4 from the rotating shaft 3, in particular making the operation of replacing the central ring 26 or its mounting on an existing screen simple and fast.

[0118] The outer section 29 of the central ring 26 is advantageously provided with a positioning seat (e.g. a concave surface) for mounting at least the forward ends 16' of the thrust vanes 12. Such a positioning seat has a cross-sectional counter shape to the section of the rear face 17 of the thrust vanes 12 which is mounted on it, so as to easily identify the correct position of the thrust vanes 12 with respect to the central ring 26.

[0119] In particular, the arrangement of the thrust vanes 12 connected to the central ring 26 makes it possible to simply and quickly determine the correct position of the thrust vanes 12 on the lateral faces 4A, 4B of the disc 4 during the assembly step, since the radial distance of the thrust vanes 12 from the rotating shaft 3 is determined by the central ring 26, while the angular position of the thrust vanes 12 around the rotating shaft 3 can be easily identified, for example by placing the rear end 16' of the thrust vane 12 at one of the vertices of the outer edge 4D of the disc 4.

[0120] 11 and 16, the lateral gaps I between the disks 4 are delimited by a lateral face 4A of the disks 4 with thrust vanes 12 (which benefit the central ring 26) and a lateral face 4B of the disks 4 without such elements mounted on a continuous rotating shaft 3. In particular, such an arrangement limits the variation of the screening section of the disk screen 1.

[0121] According to a third embodiment of the invention shown in figures 10 to 13, the thrust vanes 12 (which take advantage of the central ring 26) are arranged only on one of the lateral faces 4A, 4B of the disks 4 (specifically on all disks 4) in such a way that the thrust vanes 12 are arranged on the face 4A of the disks 4 facing in the same direction. Suitably, as is visible, for example, in the view of figure 12, the thrust vanes 12 of a disk 4 of a rotating shaft 12 are arranged angularly offset (for example by 180°) with respect to the thrust vanes 12 of a disk 4 of a successive rotating shaft 3.

[0122] According to a fourth embodiment of the invention shown in figures 15 to 18, the thrust vanes 12 (which benefit the central ring 26) are arranged on a subset of the discs 4. In particular, the rotating shafts 3 are provided with discs 4 provided with thrust vanes 12 alternating with rotating shafts 3 with discs 4 without thrust vanes 12. In particular, the discs 4 with thrust vanes 12 (which benefit the central ring 26) are provided with elements relating to both lateral faces 4A, 4B.

[0123] In operation, during such advancement of solid material on the screening surface, residues with a size smaller than the opening defined between the respective discs 4 of the rotating shafts 3 and the sleeves 20 of the successive rotating shafts 3 fall by gravity below the screening surface and, depending on their size, obtain a selection of material.

[0124] During screening, the presence of the sleeve 20 prevents, or at least limits, the entrainment of thread-like residue around the rotating shaft 3 .

[0125] According to the invention, the thrust vanes 12 of the discs 4 make it possible to expel, outside the lateral gap I between the discs 4, undesirable intervening material (fibrous plastic material, etc.) which may lead to connecting the sleeve 20 to the discs 4 and to the rotating shaft 3, thus also causing the sleeve 20 to rotate and leading to twisting of the thread-like material.

[0126] Thus, the disc screen for separating solid materials thus conceived achieves a predetermined objective.

Claims

1. A disc screen (1) for separating solid materials, comprising: A support structure (2); A plurality of rotating shafts (3) rotatably mounted on the support structure (2) and positioned parallel to one another; a plurality of discs (4) fixed to the corresponding rotating shafts (3), positioned in succession and spaced apart from one another along the corresponding rotating shafts (3), each of said discs (4) being provided with a rotation axis (Y) parallel to the corresponding rotating shafts (3) and extending according to said rotation axis (Y) between two lateral faces (4A, 4B) facing in opposite directions, each of said lateral faces (4A, 4B) of each of said discs (4) being provided with an outer edge (4D) extending around said rotation axis (Y), the outer edges (4D) of said lateral faces (4A, 4B) having a convex and polygonal shape; a drive means (5) mechanically connected to the rotating shaft (3) for actuating the disc (4) to rotate about the axis of rotation (Y) in a rotational sense (R), The disk (4) comprises at least one thrust vane (12) fixed to at least one of the two lateral faces (4A, 4B) and extending protruding from said lateral face (4A, 4B), each of said thrust vanes (12) is provided with a front surface (13) oriented according to said sense of rotation (R) and extending between an inner portion (14) and an outer portion (15) further away from said axis of rotation (Y) with respect to said inner portion (14); The front face (13) of the thrust vane (12) has a longitudinal section, the longitudinal section comprising: extending inside the lateral faces (4A, 4B) of the disc (4), with at least the internal portion (14) being located inside the external edges (4D) of the lateral faces (4A, 4B); when moving close to the axis of rotation (Y), it extends according to the direction of rotation (R) from the outer part (15) to the inner part (14), the outer portion (15) of the front face (13) of said thrust vane (12) being substantially in contact with the outer edges (4D) of said lateral faces (4A, 4B); said disc (4) comprises at least one central ring (26) fixed to at least one of said two lateral faces (4A, 4B) and extending outwardly from said lateral faces (4A, 4B) and mounted around the periphery of the corresponding rotating shaft (3); each of said central rings (26) is provided with an inner section (27) defining a through opening (28) intersected by a rotating shaft (3) and with an outer section (29) defining, relative to said inner section (27), the thickness of said central ring (26); the thrust vanes (12) extend between a forward end (16') located on the inner portion (14) of the forward face (13) and an aft end (16'') located on the outer portion (15) of the forward face (13), the thrust vanes (12) being connected at least at the forward end (16') to the central ring (26); the inner portion (14) of the forward face (13) of the thrust vane (12) is connected substantially uninterruptedly to the outer section (29) of the central ring (26); The circular screen (1), characterized in that the outer section (29) of the central ring (26) extends from a point of contact with the front end (16') of the thrust vane (12) so as to be continuous with the inner portion (14) of the front face (13) of the thrust vane (12).

2. 2. The disc screen (1) according to claim 1, characterized in that the outer edges (4D) of the lateral faces (4A, 4B) have a convex shape and the longitudinal section of the front face (13) of the thrust vane (12) is positioned inside the outer edges (4D).

3. 3. The disc screen (1) according to claim 1 or 2, characterized in that at least the inner part (14) of the front face (13) of the thrust vane (12) is placed on the lateral faces (4A, 4B) at a distance from the outer edges (4D) of the lateral faces (4A, 4B).

4. The circular screen (1) according to any one of claims 1 to 3, characterized in that the longitudinal section of the front surface (13) is delimited by dotted lines at an inclination angle (α) greater than 90° relative to a circumference, the circumference having a centre of the axis of rotation (Y) and passing through a point.

5. The disc screen (1) according to any one of claims 1 to 4, characterized in that the longitudinal section of the front surface (13) has a convex shape.

6. 6. The disc screen (1) according to any one of claims 1 to 5, characterized in that the longitudinal section of the front surface (13) has a curved shape.

7. The disc screen (1) according to any one of claims 1 to 6, characterized in that the outer part (15) of the front face (13) of the thrust vane (12) is located at the outer edge (4D) of the lateral face (4A, 4B).

8. 8. The disc screen (1) according to any one of claims 1 to 7, characterized in that the inner parts (14) of the thrust vanes (12) are located in a first zone of the lateral faces (4A, 4B) radially close to the axis of rotation (Y) and the outer parts (15) of the thrust vanes (12) are located in a second zone of the lateral faces (4A, 4B) which is located further radially away from the axis of rotation (Y) with respect to the first zone.

9. A disc screen (1) as claimed in any one of claims 1 to 8, further comprising a plurality of sleeves (20), each of which is loosely mounted externally on the rotating shaft (3) corresponding to a position between two successive discs (4) and comprises a tubular body (21) extending parallel to the rotation axis (Y) between two opposing end edges (21') positioned on corresponding side faces (4A, 4B) of the subsequent disc (4), the central ring (26) being provided with an internal section (27) defining a through opening (28) into which the corresponding end edges (21') of the tubular bodies (21) of the sleeves (20) are inserted, with a gap relative to the internal section (27).

10. 10. The disc screen (1) according to any one of claims 1 to 9, characterized in that the central ring (26) extends from the corresponding lateral face (4A, 4B) of the disc (4) with a width (H') smaller than the width (H) with which the thrust vanes (12) extend from the corresponding lateral face (4A, 4B) according to a direction parallel to the axis of rotation (Y).

Images