Plant and method for cleaning wood-based agglomerate material, deriving from MDF panels, chipboards or suchlike
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PAL PONTE DI PIAVE
- Filing Date
- 2026-01-30
- Publication Date
- 2026-08-06
Smart Images
Figure IT2026050019_06082026_PF_FP_ABST
Abstract
Description
[0001] “PLANT AND METHOD FOR CLEANING WOOD-BASED AGGLOMERATE MATERIAL, DERIVING FROM MDF PANELS, CHIPBOARDS OR SUCHLIKE”
[0002]
[0003] FIELD OF THE INVENTION
[0004] The present invention concerns a plant and the corresponding industrial method for cleaning wood-based material deriving from agglomerate material panels, such as for example MDF (Medium Density Fiberboard), chipboards, or suchlike.
[0005] In particular, the present invention is applied to clean the woody fibers from other materials, primarily for recycling purposes, for example, to make the woody fibers available to form new panels or other.
[0006] BACKGROUND OF THE INVENTION
[0007] Panels made of agglomerate material such as, for example, MDF panels, chipboards, or other, in which a certain component of medium-sized woody fibers and / or particles is compacted and chemically bonded by synthetic binders in order to achieve a desired density and mechanical strength of the panel, are known.
[0008] Plants for the end-of-life treatment of such panels are also known, in which machines known as decomposers are provided, which intervene on pieces of panels, for example less than approximately 100 mm x 100 mm in size, deriving from industrial waste or from discontinuation of use, in order to decompose and roughly separate the woody fibers from the synthetic binders, such as adhesives, resins or others, using mainly water or steam.
[0009] In the state of the art, machines are known that act on the materials in Ohmic form, that is, by hydrolysis, or by steam, or other purely chemical solutions, which, however, are being progressively abandoned due to the heavy environmental impact they entail.
[0010] Known solutions perform a coarse decomposition of the panel’s woody fibers, leaving different parts of fibers and aggregators, still agglomerated together, as well as impurities or mixed pieces of wood. This coarse decomposition also proves barely acceptable if the starting panel provides, as is commonplace, ennobling coatings made of polymer materials, which remain aggregated with the woody fibers, becoming substantially waste.
[0011] In other words, known solutions allow for a partial decomposition of the fibers,which is not always satisfactory and, in any case, is difficult to use for the recycling of the woody part, at least from an industrial point of view, in particular if the woody fiber is intended for the production of new panels of agglomerate material, having structural and mechanical characteristics substantially similar to the original ones.
[0012] In this sense, the solution according to patent document WO-A-2020226545 is known, in which an apparatus and a method for producing wood-based panels is described, in which there is provided a series of shaped rollers conformed to define a path along which the agglomerates of woody fibers being fed are broken down into smaller agglomerates and / or single fibers. In this solution, the rollers are conformed with a cylindrical base, with an external circular surface having a surface texture with spoon-shaped tips configured so as to crush the agglomerates, reducing them into smaller agglomerates.
[0013] This solution, also due to the specific conformation of the rollers, performs a mere reduction in size of the agglomerates, breaking the fibers and leaving different parts of fibers and aggregators, still agglomerated together, proving barely acceptable for the recycling of the woody fibers and becoming substantially waste.
[0014] From patent document JP-A-2001276643, a method is also known for crushing sheathing boards, of the type used as concrete formwork, broken into agglomerates with a granulometry from 50 to 200 pm, in which it is provided to peel or separate the concrete and other deposits that adhere to the pieces of wood, applying a friction crushing force, sizing the synthetic materials and recovering the sized granular wood materials. This known solution, like the previous one, also performs a mere reduction in size of the agglomerates, applying a friction crushing force, breaking the fibers and leaving different parts of fibers and aggregators, still agglomerated together, proving barely acceptable for the recycling of the woody fibers and becoming substantially waste.
[0015] Patent document EP-A- 1442855 discloses a roller screening system in which adjacent opening discs are provided, which have opening elements that extend radially outward and on the terminal surfaces of which there are recesses that define corresponding tips. The direct mechanical action of the deliberately defined tips performs a crushing of the agglomerates by impact, breaking both the fibersand also the aggregators together, but also in this case leaving different parts of fibers and aggregators still agglomerated together, obtaining materials not suitable for recycling, which substantially become waste.
[0016] A process for producing wood fiber panels is also known from patent document US-A-2024375313, in which the refined material deriving from recycled wood fiber panels is wetted, heated and pressurized with steam.
[0017] In this type of known solution, the indispensable operational need for material pressurization, which can even reach 3 bar and beyond, requires the production investment in pressurization systems and their management, increasing the costs of design, installation and management of the plant, costs that affect the material obtained.
[0018] However, this type of known solution produces a wood fiber material possibly with a fraction of wood fiber clumps and other impurities, limiting, if not sectoring, its possible destinations of use as recycled material.
[0019] There are also known solutions, such as for example described in patent document US-A-5725102, in which the separation of heavy particles from a particulate material containing the heavy particles provides the combined use of a sieve with a single-curve convex surface facing downward, and a sieve with vertical zigzag walls, which define between them channels extending upward.
[0020] This solution provides that the particles are transported through the channels with the aid of a transport air flow regulated in such a way that the heavy particles are separated in the sieve, thus only performing a size screening of the agglomerates, without any separation of the fibers from the synthetic aggregators present.
[0021] There is therefore the need to perfect a plant and develop a method that can overcome at least one of the disadvantages of the state of the art.
[0022] To do this, it is necessary to solve the technical problem of cleaning the woody fibers deriving from agglomerate material panels, even coated ones, making them almost entirely available for a recycled use, including intended for the production of a new agglomerate material panel.
[0023] In particular, one purpose of the present invention is to provide a plant and perfect a method for effectively and substantially completely cleaning the woody fibers of an agglomerate material panel, so as to separate almost all of the woodyfibers from other materials present in the panel itself.
[0024] Another purpose of the present invention is to provide a plant that allows to clean the woody fibers of agglomerate material panels without causing the woody fibers themselves to break.
[0025] 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.
[0026] SUMMARY OF THE INVENTION
[0027] The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.
[0028] In accordance with the above purposes and to solve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a plant and a method according to the present invention are applied for cleaning wood-based agglomerate material, which derives from portions of a desired size obtained from MDF (Medium Density Fiberboard) panels, chipboards, or a mixture of chipboard and MDF, and substantially consisting of a plurality of woody fibers bound together by synthetic binders.
[0029] The plant according to the present invention comprises at least one decomposition machine, which is configured to intervene on the chemical bonds of the synthetic binders, for example in Ohmic form by hydrolysis, determining a “plasticizing” effect on the agglomerate material and promoting the separation of the woody fibers.
[0030] In accordance with one aspect of the present invention, the plant also comprises at least one cleaning unit, which is operationally disposed downstream of the decomposition machine and is configured to intervene mechanically through contact on the agglomerate material and optimize the separation of the woody fibers from the synthetic binders, without causing the woody fibers to break. According to the invention, the Ohmic treatment allows to pre-hydrate the agglomerate material, and in particular the synthetic binders, so as to increase the moisture content present in the agglomerates by up to 400%, promoting the action of decomposition of the fibers, even at atmospheric pressure, without them directlybreaking. In fact, this humidification of the synthetic binders allows to exploit the heat exerted by the mechanical action of the cleaning unit in order to perform a chemical decomposition of the synthetic molecules of the binders, thus promoting the separation of the fibers from the binders without breaking the woody fibers. In fact, the action performed by the cleaning unit intervenes mechanically, and primarily, on the synthetic binders, precisely as a consequence of their hydration, inducing a sort of decomposition of the synthetic binders that leads to the separation of the woody fibers. This mechanical process of separation occurs by exploiting the “plasticized” state of the synthetic binders at exit from the decomposition machine, essentially allowing the woody fibers to free themselves from the synthetic binders, thus being cleaned of them and more available for future reuse, for the production of new panels made of agglomerate material or other.
[0031] For example, the mechanical action of the cleaning unit disposed downstream of the decomposition machine allows a substantially complete cleaning of the fibers, with recovery rates thereof that can even reach approximately 90% of the agglomerate material initially treated.
[0032] With the solution according to the present invention it is therefore possible to clean the woody fibers deriving from agglomerate material panels, even coated ones, making them almost entirely available for a recycled use, even intended for the production of a new panel of agglomerate material.
[0033] One advantage of the solution according to the present invention is being able to clean the woody fibers of an agglomerate material panel effectively and substantially completely, thus separating almost all of the woody fibers from other materials present in the panel itself.
[0034] Another advantage of the present invention is that it allows to clean the woody fibers of agglomerate material panels without causing the woody fibers themselves to break.
[0035] It is within the scope of the present invention to provide that the cleaning unit can comprise at least one screening device, which is provided with a plurality of rotating screening members disposed, for example, substantially parallel and in sequence to each other. The rotating screening members are thus configured, in turn, to transport and mechanically stress the agglomerate material, causing at leastthe reciprocal separation of the woody fibers with respect to the synthetic binders. In some advantageous embodiments, each rotating screening member can comprise a plurality of rotating elements disposed substantially coaxial and separated from each other by a specific screening distance, which are configured to progressively transport the agglomerate material to a following rotating screening member. Each rotating element also comprises a plurality of radial protuberances, which are configured to mechanically stress the agglomerate material, causing at least the reciprocal separation of the woody fibers with respect to the synthetic binders.
[0036] In this way, each rotating screening member, by rotating, simultaneously performs both an action of transporting the agglomerate material and also a mechanical action of breaking the synthetic binders between the woody fibers, cleaning them. The screening distance provided between the rotating elements allows the clean fibers to pass, thus performing a dimensional screening of the clean fibers from those that instead still need to be treated mechanically by the rotating screening members, before falling between one rotating element and the other.
[0037] It is within the scope of the present invention to provide that the cleaning unit can comprise at least one scraping device, which is provided with a centrifugal element inside which there is disposed at least one rotating radial element. The latter is configured to mechanically scrape the agglomerate material, causing at least the separation of the woody fibers from the synthetic binders.
[0038] Advantageously, the centrifugal element is disposed downstream of the rotating screening members, so as to intervene on the part of agglomerate material that has not passed the screening through the rotating elements and thus optimize the percentage amounts of clean woody fiber at the end of the cycle. However, it is not excluded that the scraping device could operate effectively on the agglomerate material even without providing, upstream, the mechanical action of the rotating screening rollers.
[0039] In some advantageous embodiments, the centrifugal element can comprise a screening chamber, which is configured to accommodate the agglomerate material and is provided with at least one screening wall, the latter having a plurality of passage perforations for the woody fibers. Advantageously, the radial element cancomprise at least one scraping member, which is disposed rotating inside the screening chamber and is configured to operate rotatably in cooperation with at least the screening wall and perform a mechanical action of separation of the woody fibers from the synthetic binders.
[0040] In this way, the woody fibers mechanically separated by the scraping member and, therefore, clean of the synthetic binders, pass through the passage perforations in the screening wall, leaving inside the screening chamber the residues of synthetic binders and the parts of agglomerate material that require further scraping passes by the radial element.
[0041] It is within the scope of the present invention to provide that the cleaning unit can comprise at least one finishing device, which is provided with one or more ducts with a serpentine, that is, substantially zigzagged, development, inside which the passage of the agglomerate material is induced. Each duct is configured to define specific mechanical impact surfaces, for example alternating according to the width of the zigzagged path, such as to cause at least the detachment of the synthetic binders from the woody fibers by mechanical impact.
[0042] Advantageously, the zigzagged development duct is disposed downstream of the centrifugal element and, possibly, of the rotating screening members, so as to intervene for a finishing cleaning on the woody fibers already separated from the synthetic binders and previously screened, further optimizing the percentage amounts of clean woody fiber at the end of the cycle. However, it is not excluded that the finishing device could operate effectively on the agglomerate material even without providing, upstream, the mechanical action of the scraping device and / or, possibly, of the rotating screening rollers.
[0043] In some advantageous embodiments, the finishing device can comprise at least one selective obstruction member, for example a blade or suchlike, which is disposed in cooperation with the duct so as to selectively vary the passage crosssection thereof and, consequently, the passage speed of the agglomerate material.
[0044] In accordance with another aspect of the present invention, the plant comprises at least one de-watering member, also known as a de-watering member, which is disposed in cooperation with both the decomposition machine and also the cleaning unit, and is configured to remove process water residues from the agglomerate material. In some embodiments, the de-watering member can beprovided immediately downstream of the decomposition machine, that is, at exit from one or more cleaning processes of the cleaning unit, for example immediately downstream of the screening device, or of the scraping device, or in other operating conditions.
[0045] DESCRIPTION OF THE DRAWINGS
[0046] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:
[0047] - fig. 1 is a schematic lateral view of a plant for cleaning wood-based agglomerate material, originating from MDF panels, chipboard or suchlike, according to the present invention;
[0048] - fig. 2 is a schematic cross-section of a piece of panel made of agglomerate material, at entry to the plant of fig. 1 ;
[0049] - fig. 3 is a schematic cross-section of the piece of panel made of agglomerate material of fig. 2, at exit from a first step of decomposition of the plant of fig. 1; - fig. 4a is a detailed view of a screening device for cleaning wood-based agglomerate material, according to the present invention;
[0050] - fig. 4b shows a plan view of fig. 4a;
[0051] - fig. 4c shows an enlarged detail of fig. 4a;
[0052] - fig. 5 is a schematic cross-section of the piece of panel made of agglomerate material of fig. 2, at exit from the screening device of figs. 4a and 4b;
[0053] - fig. 6 is an enlarged schematic view of a scraping device for cleaning wood-based agglomerate material, according to the present invention;
[0054] - fig. 7 is a schematic cross-section of the piece of panel made of agglomerate material of fig. 5, at exit from the scraping device of fig. 4;
[0055] - fig. 8 is an enlarged schematic view of a finishing device for cleaning woodbased agglomerate material, according to the present invention; and
[0056] - fig. 9 is a schematic cross-section of the piece of panel made of agglomerate material of fig. 7, at exit from the scraping device of fig. 4.
[0057] We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of theinv ention itself, since the scope of protection is defined by the claims.
[0058] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION
[0059] With reference to the attached drawings, a plant 10 according to the present invention is shown, as a whole, for cleaning wood-based agglomerate material 100 deriving from MDF (Medium Density Fiberboard) panels, chipboards or combinations thereof, of a known type and not schematized in the attached drawings, in order to clean the agglomerate material 100 until it is substantially recovered to recycle its use.
[0060] By way of example only, and with reference to the schematization of fig. 2, the agglomerate material 100 is understood as a piece, or a portion, for example with measurements of approximately 80x80 mm for the thickness of the panel, and composed mainly of woody fibers 110 of medium size compacted and chemically bonded together by synthetic binders 120, for example resins, glues or other, in order to obtain a desired density and mechanical resistance of the panel. For completeness of application, the present description will consider pieces of agglomerate material 100 deriving from panels coated with an ennobling coating 130 made of plastic, paper or other material.
[0061] However, the possibility that the plant 10 according to the present invention can operate on the agglomerate material 100 deriving from raw panels, that is, without ennobling coating 130, is not excluded.
[0062] The plant 10 according to the present invention substantially comprises a decomposition machine 11, a cleaning unit 12, and a drying device 13. A dewatering member 14 is also part of the plant 10 according to the present invention, the functions of which will be described below in relation to the different possible dispositions thereof within the operating sequence of the plant 10.
[0063] The decomposition machine 11 is of a substantially known type and is generically indicated with a rectangle in the attached drawings. Specifically, the decomposition machine 11 is fed with the pieces of agglomerate material and is configured to intervene on the synthetic binders 120 in order to decompose theagglomerate material 100 and separate, at least coarsely, the woody fibers 110 from the synthetic binders 120, using predominantly water, for example in Ohmic form, that is, by hydrolysis, or by steam, thereby defining a “plasticizing” effect on the synthetic binders 120 that lose, at least for the most part, their binding characteristics, allowing a separation of the woody fibers 110 and, therefore, a substantial decomposition of the agglomerate material 100.
[0064] In particular, the decomposition machine 11 , by performing the treatment in Ohmic form, allows to hydrate the agglomerate material, and in particular the synthetic binders 120, in advance, so as to increase, up to 200%, but even to 400%, the moisture present in the agglomerates themselves.
[0065] This considerable increase in moisture promotes the chemical decomposition of the synthetic binder molecules, even at atmospheric pressure, in particular due to the heat exerted, as we will see, by the mechanical actions of the cleaning unit 12, promoting the separation of the woody fibers 110 from the synthetic binders 120, without the breakage of the woody fibers 110.
[0066] Fig. 3 schematically represents a possible decomposed conformation of the agglomerate material 100 at exit from the decomposition machine 11.
[0067] Specifically, the cleaning unit 12 substantially comprises a screening device 15, a scraping device 16 and a finishing device 17, operatively disposed in sequence to each other.
[0068] In general, the cleaning unit 12 intervenes mechanically through contact on the agglomerate material 100 decomposed by the decomposition machine 11 , optimizing the separation of the woody fibers 110 from the synthetic binders 120, without causing the woody fibers 110 to break.
[0069] The screening device 15 comprises a support frame 18 on which there is mounted in sequence a plurality of rotating screening members, or screening rollers 19, in this specific case eleven. The number of screening rollers 19 on the support frame 18 can vary between approximately five and approximately twenty, preferably between five and fifteen, between ten and fifteen, etc.
[0070] The support frame 18 is conformed so as to guarantee that the last screening roller 19, with respect to the direction of feed of the agglomerate material 100, has its longitudinal axis of rotation at an absolute operating height higher than the first screening roller 19 provided. In this way, the sequence of the screening rollers 19defines an upward inclination, with respect to the direction of feed of the agglomerate material 100.
[0071] The inclination defined by the mounting of the screening rollers 19 has an amplitude of a certain angle a, which can advantageously be comprised between approximately 0° and approximately 25°.
[0072] In some advantageous embodiments, the angle a can be selectively modified to deliberately vary the falling conditions of the clean fibers 110.
[0073] The screening rollers 19 thus disposed in sequence allow to transport and mechanically stress the agglomerate material 100, causing at least the reciprocal separation of the woody fibers 110, with respect to the synthetic binders 120. In particular, each screening roller 19 is substantially defined by a plurality of rotating elements, or star elements 20, disposed substantially coaxial and separated from each other by a specific screening distance D.
[0074] According to some embodiments, the number of rotating elements 20 in a screening roller 19 can range from approximately twenty to approximately one hundred, preferably between thirty and one hundred, between thirty and eighty, between forty and sixty, between thirty and fifty, etc.
[0075] In an advantageous embodiment, each screening roller 19 can comprise approximately forty individual star elements 20, disposed at a screening distance D of a dozen millimeters from each other.
[0076] Each star element 20 comprises a plurality of radial protuberances 21, in this specific case in a number comprised between five and fifteen, preferably between five and twelve, for example between five and ten, which extend radially by a magnitude R that is comprised between approximately 0.2 times and approximately 0.6 times the overall diameter De of the entire star element 20 (fig.
[0077] 4c), and have a rounded radial end to prevent the woody fibers 120 from accidentally braking during the mechanical action of purification from the synthetic binders 120. The radial protuberances 21 are, in fact, configured to mechanically stress the agglomerate material 100, and in particular intervene on the synthetic binders 120 plasticized by hydration by the action of the decomposition machine 11 , generating the desired amount of heat on the chemical bonds of the synthetic binders 120 and promoting the decomposition thereof, with the consequent separation of the woody fibers 110 with respect to the syntheticbinders 120 themselves.
[0078] This mechanical action of the star elements 20 on the synthetic binders 120, together with the inclination of the defined screening rollers 19, facilitates a fall by gravity of the woody fibers 110, already previously cleaned or just cleaned by the screening device 15, through the screening distances D defined between the star elements 20 of one screening roller 19 and the other. The clean woody fibers 110 continue toward the finishing device 17 and the drying device 13, while the agglomerate material 100 arriving at the end of the sequence of the screening rollers 19 is fed, for example by a screw feeder or other known feeding system, toward the scraping device 16 and is repositioned, for example by means of a belt or other known conveying system, at entry into the screening device 15, so as to be subjected to a new cycle of transport and mechanical stress by the rollers 19 and their star elements 20, and so on.
[0079] Fig. 5 schematically represents a possible clean conformation of the agglomerate material 100 at exit from the screening device 15.
[0080] The scraping device 16 comprises a centrifugal element, or more simply centrifuge 22, having a screening chamber 23 configured to accommodate the agglomerate material 100 and defined substantially by a screening wall 24, in this specific case with a cylindrical conformation. The cylindrical wall 24 advantageously comprises, in a lower portion thereof, a plurality of passage perforations 25, having a desired width such as to allow the passage of the woody fibers 120 of desired sizes.
[0081] In the embodiment shown, the centrifuge 22 is mounted on the same support frame 18 as the screening device 15, so as to be substantially integrated therewith. Inside the centrifuge 22 there is axially disposed a rotating radial element 26, which is configured to mechanically scrape the agglomerate material 100, causing a further separation of the woody fibers 110 from the synthetic binders 120.
[0082] The radial element 26 comprises one or more scraping members, or more simply scrapers 27, disposed inside the screening chamber 23 and operatively disposed in cooperation with the screening wall 24, so as to perform a mechanical action of separation, like a sort of comb, of the woody fibers 110 from the synthetic binders 120, and facilitate the fall of the separated woody fibers 110 through the passage perforations 25.This particular mechanical scraping action performed by the scrapers 27, always as a result of the hydration given to the agglomerate material 100 by the action of the decomposition machine 11 , generates the desired amount of heat on the chemical bonds of the synthetic binders 120 and promotes the decomposition thereof, resulting in an effective separation of the woody fibers 110, even from possible ennobling coatings 130.
[0083] In addition, the hydration of the agglomerate 100 allows the scrapers 27 to act effectively even on agglomerates with sizes that can be of the order of millimeters, even up to 5mm and above.
[0084] The woody fibers 110 thus cleaned join those previously cleaned by the screening device 15 and continue toward the finishing device 17, and continue toward the drying device 13, while the agglomerate material 100 that does not pass through the passage perforations 25 is once again subjected to the mechanical action of the scrapers 27, until the desired cleaning of the woody fibers 110 is achieved.
[0085] We do not exclude solutions of the plant 10 according to the present invention, for example in the case of specific treatment of only agglomerate 100 deriving from MDF panels alone, in which the use of the screening device 15 can be excluded, feeding the agglomerates 100 treated in Ohmic form by the decomposition machine 11 directly into the scraping device 16. In fact, with this type of MDF agglomerates 100, humidified even up to 400%, the mechanical action of the scrapers 27 alone is sufficient to generate the heat necessary to decompose the chemical bonds of the synthetic binders 120, separating the woody fibers 110 without breaking them.
[0086] Fig. 7 schematically represents a possible clean conformation of the agglomerate material 100 at exit from the scraping device 16.
[0087] The de-watering member 14 is, in the solution schematized in fig. 1, disposed downstream of the decomposition machine 11, and in particular at exit from the scraping device 16, and is configured in a known manner to extract the water from the woody fibers 110 cleaned to this point mechanically, for example by pressing.
[0088] It is not excluded, in other embodiments and as schematized with a dashed line in fig. 1, that the de-watering member 14 can be disposed downstream of the decomposition machine 11 but upstream of the cleaning unit 12, in order to obtaindifferent cleaning conditions of the agglomerate material 100 being fed.
[0089] The finishing device 17 is operatively disposed in cooperation with a ventilation member, of a substantially known type and not shown in the attached drawings, which is configured to generate an air flow that causes the woody fibers 110 to be carried through the finishing device 17 itself, and other parts of the plant 10 according to the present invention, at a certain speed.
[0090] In particular, the finishing device 17 is defined by a plurality of ducts 28 with a serpentine, that is, zigzagged development, which are disposed substantially horizontally and within which the passage of the agglomerate material 100 is forcibly induced, as an effect of the air flow generated by the ventilation member. Each duct 28 internally defines specific mechanical impact surfaces 29 which the woody fibers 110 impact against, causing the detachment of the residual synthetic binders 120, the separation between the woody fibers 110, and performing a finishing cleaning that allows to recover a percentage that can reach as much as 90% of the woody fibers 110 contained in the agglomerate material 100 initially fed into the plant 10. Also due to the Ohmic hydration initially given by the decomposition machine 11, a greater resistance to breakage of the woody fiber 110 is determined.
[0091] The woody fibers 110, so finely prepared for the final cleaning step, continue toward the drying device 13, in which a substantial drying of the woody fibers 110 is operated, and a further cleaning by means of a wind sifter, of a substantially traditional type, and subsequently into a dryer or directly to the resin plant, other combinations being possible depending on the specific process needs and the product to be obtained.
[0092] Fig. 9 schematically represents a possible clean conformation of the agglomerate material 100 at exit from the finishing device 17.
[0093] In the embodiment schematized in the attached drawings, the finishing device 17 comprises at least one selective obstruction member, or movable blade 30, disposed in cooperation with a corresponding duct 28. The movable blade 30 can selectively take different transverse positions relative to the passage cross-section of the corresponding duct 28, so as to vary both the air passage gap through the cross-section itself and also, consequently, the passage speed of the air flow and, therefore, the mechanical impact intensities of the agglomerate material 100 andthe functionalities for cleaning the woody fibers 110 from the synthetic binders 120. This adjustment of the air flow actuated by each movable blade 30 also allows to avoid the risk of accumulation of the woody fiber 110 on the impact surfaces 29, increasing the overall volumetric capacity for recycling the woody fiber 110. It is clear that modifications and / or additions of parts may be made to the plant 10 and to the method as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.
[0094] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of plant and method for cleaning wood-based agglomerate material, deriving from MDF or chipboard panels, or suchlike, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
[0095] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.
Claims
CLAIMS1. Plant (10) for cleaning wood-based agglomerate material (100) substantially consisting of a plurality of woody fibers (110) bound together by means of synthetic binders (120), said plant (10) comprising at least one decomposition machine (11) configured to intervene on the chemical bonds of said synthetic binders (120), characterized in that it comprises at least one cleaning unit (12) operationally disposed downstream of said decomposition machine (11) and configured to intervene mechanically through contact on said agglomerate material (100), optimizing the separation of the woody fibers (110) from said synthetic binders (120), without causing said woody fibers (110) to break.
2. Plant (10) as in claim 1, characterized in that said cleaning unit (12) comprises at least one screening device (15) provided with a plurality of rotating screening members (19) configured to transport and mechanically stress said agglomerate material (100), causing at least the reciprocal separation of said woody fibers (110) with respect to said synthetic binders (120).
3. Plant (10) as in claim 1 or 2, characterized in that said cleaning unit (12) comprises at least one scraping device (16) provided with a centrifugal element (22) inside which there is disposed at least one rotating radial element (26) configured to mechanically scrape said agglomerate material (100), causing at least the separation of said woody fibers (110) both from said synthetic binders (120) and from possible ennobling coating parts (130).
4. Plant (10) as in claim 1, 2 or 3, characterized in that said cleaning unit (12) comprises at least one finishing device (17) provided with one or more ducts (28) with a zigzagged development, inside which the passage of said agglomerate material (100) is induced and each being configured to define specific mechanical impact surfaces (29) such as to cause at least the detachment of said synthetic binders (120) from said woody fibers (110).
5. Plant (10) as in claim 2, characterized in that each of said rotating screening members (19) comprises a plurality of rotating elements (20) disposed substantially coaxial, separated from each other by a specific screening distance (D) and configured to mechanically transport said agglomerate material (100), each of said rotating elements (20) comprising a plurality of radial protuberances (21) configured to mechanically stress said agglomerate material (100), causing atleast the reciprocal separation of said woody fibers (110) with respect to said synthetic binders (120).
6. Plant (10) as in claim 5, characterized in that each of said rotating screening members (19) comprises a number of said rotating elements (20) of between approximately thirty and approximately one hundred.
7. Plant (10) as in one or the other of the previous claims from 2 onward, characterized in that said screening device (15) comprises a support frame (18) on which said rotating screening members (19) are mounted in sequence.
8. Plant (10) as in claim 7, characterized in that said rotating screening members (19) are in a number comprised between approximately five and approximately twenty.
9. Plant (10) as in claim 7 or 8, characterized in that said support frame (18) is conformed in such a way as to operatively dispose said rotating screening members (19) inclined upward, with respect to a direction of feed of said agglomerate material (100).
10. Plant (10) as in claim 9, characterized in that said inclination has an amplitude of a specific angle (a) comprised between approximately 0° and approximately 25°.
11. Plant (10) as in claim 10, characterized in that said specific angle (a) is selectively variable in order to modify the inclination conditions of said rotating screening members (19).
12. Plant (10) as in claim 6, characterized in that each of said rotating elements (20) comprises a plurality of radial protuberances (21) configured to mechanically stress said agglomerate material (100), causing the separation of said woody fibers (110) with respect to said synthetic binders (120).
13. Plant (10) as in claim 12, characterized in that said radial protuberances (21) are in a number comprised between approximately five and approximately fifteen.
14. Plant (10) as in claim 12, characterized in that said radial protuberances (21) extend radially by a magnitude (R) comprised between approximately 0.2 times and approximately 0.6 times the overall diameter (De) of the corresponding one of said rotating elements (20).
15. Plant (10) as in claim 3, characterized in that said centrifugal element (22) comprises a screening chamber (23) configured to accommodate said agglomeratematerial (100) and provided with at least one screening wall (24) having a plurality of passage perforations (25) for said woody fibers (110).
16. Plant (10) as in claim 15, characterized in that said screening wall (24) has a substantially cylindrical conformation.
17. Plant (10) as in claim 15 or 16, characterized in that said passage perforations (25) are made in an operatively lower part of said screening wall (24) in a surface percentage comprised between approximately 40% and approximately 70%, relative to the total surface.
18. Plant (10) as in claims 3 and 15, characterized in that said radial element (26) comprises at least one scraping member (27) disposed rotating inside said screening chamber (23) and configured to operate rotatably in cooperation with at least said screening wall (24) and perform a mechanical action of separation of said woody fibers (110) from said synthetic binders (120).
19. Plant (10) as in claim 4, characterized in that said finishing device (17) comprises at least one selective obstruction member (30) disposed in cooperation with a corresponding one of said ducts (28) and configured to selectively vary the passage cross-section of the corresponding one of said ducts (28), so as to consequently vary the passage speed of said agglomerate material (100).
20. Plant (10) as in one or the other of the previous claims, characterized in that it comprises at least one dehydration member (14) disposed in cooperation with both said decomposition machine (11) and also said cleaning unit (12), and configured to remove water residues from said agglomerate material (100).
21. Method for cleaning wood-based agglomerate material (100) substantially consisting of a plurality of woody fibers (110) bound together by means of synthetic binders (120), comprising at least a first step of decomposition in which, by means of a decomposition machine (11), an intervention is performed on the chemical bonds of said synthetic binders (120) so as to promote the separation of said woody fibers (110), characterized in that it comprises at least a second step of cleaning, downstream of said first step of decomposition, in which, by means of a cleaning unit (12), a mechanical action through contact is performed on said agglomerate material (100), optimizing the separation of the woody fibers (110) from said synthetic binders (120), without causing said woody fibers (HO) to break.