FROM SHEET MATERIAL

The invention relates to a method and plant (1) for the treatment of trimmings (R) from sheet material, comprising a pipe (2) of transporting air defined by perimetric walls (21), in which rotating paddles (3) are assembled, destined for generating a flow of air for transporting said trimmings (R) in the pipe (2), wherein the plant comprises:

- a first rotating blade (41)

- a second fixed blade (42)

a third blade (43) alternatively rotating or fixed

suitable for effecting a shredding of the trimmings (R) by shearing and wherein the rotating blades are positioned integrally with the rotor of the paddles and the fixed blades are fixed integrally with the perimetric walls. PLANT AND METHOD FOR THE TREATMENT OF TRIMMINGS OBTAINED FROM SHEET MATERIAL.

DESCRIPTION TECHNICAL FIELD

The present invention relates to the general field of plants and methods for the treatment of trimmings cut from sheet material, in particularly, but not exclusively, extremely thin sheets with thicknesses < 10 microns made of plastic, thermoplastic materials used in numerous industries including the textile sector, therefore also comprising, among the materials that can be treated with the invention object of the present description, woven or non-woven fabrics.

In the following description and enclosed claims, the term "sheet material" refers to all materials deriving from end-products having two dimensions much larger than the third, such as, for example, sheets, foils, plates, pieces of fabric and the like.

These trimmings form a discard to be treated and managed for disposal or possible production recycling. STATE OF THE ART

During the processing of sheet material, such as paper, cardboard or plastic films (typically - but not exclusively - for packaging or the like) a cutting operating of trimmings is normally effected.

1 Said trimmings generally consist of pieces of material that prevalently extend in a longitudinal direction, thus appearing in the form of extremely long, but thin and narrow, strips.

These trimmings may or may not be wound onto spools/bobbins, depending on the processing.

It is known that it is relatively complex to move, store and dispose of trimmings, due to their form, material and dimensions (they are light but extremely voluminous) and cannot be adequately managed without appropriate instruments.

Systems with paddle fans are often used for moving them, which generate a flow of transporting air that entrains the trimmings towards the fragmentation mills or compacting machines.

Although they are functional in principle, the Applicant has observed that these known systems have various drawbacks.

First of all, systems with crushing mills have considerable dimensions, a definitely high cost, and significant energy consumptions, proportional to the dimensions and weight of the dynamic elements and functioning principles.

Furthermore, especially when the trimmings consist of an extremely thin plastic material, the fans used

2 for generating the transporting air flow tend to jam: the trimmings, in fact, especially if long, become intertwined with each other forming an actual cord which often becomes twisted between the paddles of the fans, blocking their rotation; alternative methods for generating the transporting air flow are sometimes used (for example, methods that exploit the Venturi effect to avoid installing the paddles of the fan in the passage area of the trimmings) , but these have proved to be unsatisfactory for the reasons indicated above. OBJECTIVES AND SUMMARY OF THE INVENTION

The objective of the present invention is to overcome the drawbacks and limits of the known art, in particular to provide a plant and method for the treatment of trimmings from sheet material, which is simple to install, inexpensive, not bulky, with low energy consumptions and not subject to jamming (therefore extremely reliable) .

A first object of the present invention relates to a plant according to the enclosed claim 1.

A second object of the invention is a method for the treatment of trimmings cut from sheet material according to the relative enclosed independent claim.

The sub-claims, which should be considered as being an integral part of the description, have optional and

3 advantageous characteristics of the present invention.

The general idea at the basis of the invention is to effect a shredding of the trimmings by shearing, close to the paddles of the fan, so that there is no risk of the trimmings becoming twisted around them or around the shaft of the fan.

More specifically, in a preferred embodiment:

1) Effecting a shredding operation using a suitably designed group of blades that are reciprocally engaged so as to guarantee cutting by shearing in all situations

2) Preferably applying the blades on a blower that creates a flow of transporting air so as to:

• prevent the trimmings from becoming intertwined with each other and with the blower conveyed by the blower itself. In addition to creating a transporting flow, in fact, it also becomes a cutting instrument.

• combine the "fan" components and "blades" into a single component which reduces the spaces and encumbrances and consequently consumptions.

In this way, the shredding avoids jamming the paddles of the fan or, if the transporting air source is different from a fan, it avoids hindering the chopping operation.

4 Furthermore, this allows small and relatively inexpensive machines to be produced, so that they can be efficient with both large volumes and with reduced volumes of material to be treated.

According to a particularly interesting optional characteristic, downstream of the shredding operation of the trimmings, the same can be compacted into blocks having the dimensions of a tile, for example by melting (also partially) the same, when they are made of plastic material, preferably a suitable thermoplastic material .

Other advantageous optional characteristics of the invention are contained in the enclosed claims, which should be considered as being an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereunder with reference to non-limiting examples, provided for purely illustrative purposes in the enclosed drawings. Said drawings illustrate some views of embodiment solutions of the present invention and, when appropriate, reference numbers are used for univocally indicating structures, components and materials.

Homologous elements in different figures are indicated by the same reference number.

5 Figure 1 illustrates a view from above of a simplified example of a plant according to the invention;

Figure 2 illustrates a side view of a simplified example of a plant according to the invention;

Figure 3 illustrates a front view of part of the plant of the previous figures;

Figure 4 illustrates a partially sectional view from above of the part of the plant of the previous figure;

Figures 5 and 6 are details shown from the front and from above respectively, of the part of the plant of figures 3 and 4 ;

Figure 7 illustrates a side view of a blade of the plant of the previous figures;

Figure 8 illustrates a section of a tile of trimmings treated with the plant of the previous figures and subsequently compacted.

DETAILED DESCRIPTION OF THE INVENTION

Whereas the invention can undergo various modifications and alternative constructions, some embodiment solutions are shown in the drawings and are described in detail hereunder.

It should be understood however that there is no intention of limiting the invention to the specific

6 embodiment illustrated, but, on the contrary, the invention intends to cover all modifications, alternative constructions, and equivalents that fall within the scope of the invention as defined in the claims.

The use of "for example", "etc", "or" indicates non-exclusive alternatives without limitations, unless otherwise specified. The use of "comprises" means "comprises, but not limited to", unless otherwise specified.

The terms "horizontal", "vertical" and similar terms refer to current terminology, wherein "vertical" indicates a direction parallel to that of the force of gravity vector g.

Generally speaking, the idea at the basis of the invention is to provide a plant for the treatment of trimmings from sheet material, comprising a pipe of transporting air defined by perimetric walls, a source of transporting air for generating a flow of transporting air in the pipe for transporting said trimmings in the pipe, wherein: a first rotating blade, a second fixed blade and a third blade which, depending on the application, can be rotating or fixed, are envisaged and active inside the pipe.

In this way, there are solutions with at least two

7 fixed blades and one rotating blade, others with two rotating blades and one fixed blade or yet others with a plurality of fixed blades and rotating blades.

The rotating blades rotate around a rotation axis, preferably the same barycentric axis as the pipe in which they are assembled, and are engaged between the fixed blades, to effect an actual shearing, which chops the trimmings, transported to the cutting area by means of the transporting air flow, with an actual shearing operation.

As far as the transporting air sources are concerned, these can be of various types: paddle fans, turbines, systems that exploit compressed air (for example, by means of the Venturi effect or the like) ; a preferred solution in which the source is a fan is described hereunder.

With reference to figures 1 and 2, these, in fact, show a preferred example of a plant 1 for the treatment of trimmings (R) from sheet material.

The plant 1 according to the invention comprises at least one transporting air pipe 2 defined by perimetric walls 21, in which rotating paddles 3 are assembled, destined for generating a flow of air.

Upstream of the pipe 2, there is a feeding device of the trimmings R to be treated: said device is not

8 illustrated as it is not an object of the present invention and is of a type known per se.

It is capable of unwinding one or more trimmings R from a spool, which are typically in the form of elongated filaments.

The flow of transporting air generated by the paddles 3 entrains the trimmings R into the pipe 2, conveying them.

The paddles 3 are motorized, for example by means of an electric motor M (figure 4) or the like, and in the example, are part of a common rotor of a centrifugal machine, in particular a suction and pressing fan; alternatively, the fan can also be of the pressing type alone or of the suction type alone.

The dimensions, type and conformation of the paddles 3 are within the reach of the detailed design of a skilled person in the field, when the operative functioning parameters are known.

In the example, the pipe 2 can be ideally divided into various sections as illustrated hereunder:

a feeding pipe 2a, positioned upstream of the paddles 3 in the advance direction of the air flow,

a casing pipe 2b, immediately downstream of the paddles 3,

an outlet pipe 2c, downstream of the casing pipe

9 2b,

a discharge pipe 2d, downstream of the outlet pipe

2c.

All the pipes 2a, 2b, 2c, 2d are in fluid (or flow) communication with each other and if the paddles 3 are those of a fan, the pipe 2b corresponds to that of the casing of the fan itself and is at least partly defined by the walls of the fan casing, as illustrated in the example of the figures.

According to the invention, the plant has a total of at least three blades: in the example, there is a first blade 41 rotatingly integral with the paddles 3 and two blades 42 and 43, fixed with respect to the pipe 2; more generically, the fixed blades are integral with a wall of the plant which is fixed with respect to the paddles; for example integral with a wall of the fan casing.

Generally speaking, the rotating blade 41 (or rotating blades if there are more than one) , can be motorized with a specific motor, or, as in the case of the example, it can be advantageously positioned on the paddles 3, so as to be rotated by the same motor that activates the paddles themselves.

Both the rotating blade 41 and the fixed blades 42 and 43 are situated inside the pipe 2, in a passage

10 area for the flow of transporting air and, in particular, in the area in which the paddles intercept the trimmings R which are carried by the air in a functioning condition.

If the actuating motor M of the paddles is housed in the pipe 2, as in the example illustrated, it is preferably positioned downstream (again in the advance direction of the air flow) of the blades 41, 42, so that the transmission shaft AT of the motor M (connected to the hub of the paddles 3) is positioned in an area that the trimmings R can only reach after having been chopped by shearing on the part of the blades 41, 42 and 43 themselves.

The rotating blade 41 and the fixed blades 42 and 43 are reciprocally engaged with each other in order to shred the trimmings R by means of a shearing action.

The rotating blade 41 is advantageously positioned on the paddles 3 or, as in the example, at the hub from which the paddles themselves 3 branch out.

In the example (figure 4), a rotating blade 41 is shown, but two or three or more can also be envisaged.

Furthermore, in the example illustrated, with particular reference to figures 3 to 6, there are two fixed blades (coupled) , the first fixed blade 42 and a second fixed blade 43.

11 The second fixed blade 43 is adjacent to the first blade 42 and spaced from the latter; the distance between the two fixed blades 42 and 43 is slightly greater than the thickness of the rotating blade 41, so that, during the rotation of the rotating blade 41, the latter passes between the fixed blades 42 and 43 and guarantees an optimum shearing of the trimmings R.

It should be understood that the trimmings R are also cut if they reach the blades 41, 42 and 43 in areas far from the shearing area (that can be considered as coinciding with the position of the fixed blades 42, 43) : as the trimmings are flexible, in fact, they are first engaged and then entrained by the rotating blade 41 towards the fixed blades 42 and 43 and thereby cut.

In any case, the shearing operation, in conjunction with the rotation of the paddles, absolutely prevents the trimmings R from becoming intertwined and forming cords that could block the plant as, in any case, the principle ensures that intertwined trimmings are cut into a length that cannot create problems for the functioning of the plant.

A further advantage is of particular importance and occurs when the rotating blade 41 is integral with the paddles 3 (as in the example): in this case, in fact,

12 even when the plant must be stopped for technical pauses or stoppages, when it is re-started, the trimmings R remaining in the pipe (upstream of the rotating blade 41) are correctly re-taken by the air flow and cut.

As a result of a further particularly advantageous and optional characteristic, the blades 41, 42, 43 - at least one, preferably all - have at least a serrated cutting edge 45, as in figure 7.

This figure shows, for clarity, a fixed blade 42, which has two opposite serrated cutting edges; the rotating blade 41 is produced analogously, with one or two serrated edges and is not shown for the sake of brevity.

It should be noted that the presence of the serration 45 offers various advantages:

firstly, serrated blades do not easily lose their sharpness as in the case of straight blades,

secondly, they effect a shearing of the trimmings which takes place thanks to the tearing of the same (as a result of the grip caused by the serration and reciprocal engagement between fixed and movable blades) , so that even in the case of reduced sharpening, the correct functioning is guaranteed and the replacement intervals and/or sharpening of the

13 blades 41, 42, 43, are reduced,

thirdly, the fact that at least the rotating blade is serrated, ensures that it is able to entrain the trimmings R more accurately and safely (grip of the serrated teeth) towards the shearing area (where it encounters the fixed blades 42, 43 which act in an opposite direction) ; in the case of non-serrated blades and trimmings R made of a particularly smooth material, the gripping and entrainment (grip) effect may in fact be partially lost, with the result that the pieces of cut trimmings may have a greater length.

A component 46 engaged with the hub AT and easily interchangeable, can be used for coupling the rotating blade 41 with the rotating paddles 3.

With reference to figures 1 and 2, a heated chamber

10 for the accumulation and solidification of the chopped trimmings, into tile-shaped blocks, can be envisaged downstream of the paddles 3; this expedient forms an independent aspect of the invention and can be used when the trimmings R are made of a plastic, or more appropriately thermoplastic, material.

In the example, the chamber 10 is situated downstream of the discharge pipe 2d; it is reached by the chopped trimmings R, which are sent there by the transporting air generated by the paddles 3.

14 Once the chopped trimmings R have reached the chamber 10, they accumulate and the temperature of the chamber 10 is raised (for example by means of electric resistances, blown hot air or similar heating means).

In a particularly advantageous and optional embodiment, it is the walls of the chamber 10 that are heated and, in turn, heat the chopped trimmings housed in the chamber 10.

The heating temperature reaches levels close to the melting point or at least a softening temperature of the material of the trimmings R or, more generally, a temperature at which the chopped trimmings R thicken together, reducing the overall volume.

In this way, the trimmings R present in the chamber 10 begin a gradual melting process forming a single mass and, after being suitably pressed, at the outlet of the chamber 10, at room temperature, they resolidify to be evacuated in the form of semisolid tiles and subsequently transported and moved in an extremely simple and rapid way.

They would otherwise have to be treated as loose materials which tend to become dispersed in the environment, occupying a greater volume and difficult to manage.

In the advantageous embodiment in which the walls

15 of the chamber are heated, and with reference to figure 8, the tiles MR of trimmings R treated in the chamber 10 have an outer shell G of solidified material and an internal core N in which the trimmings are not solidified .

This allows the tiles MR to be moved as a solid and compact body with the advantages indicated above.

The heating of the outer surfaces alone of the tile-shaped blocks, allows a reduction in the residence time in the chamber 10 or, equivalently, the energy necessary for obtaining the minimum heat in the chamber 10 for reaching the desired softening state.

Finally, it should be noted that the formation operation of tiles MR of chopped trimmings R can be effected either in continuous or batchwise.

In the former case, the trimmings R reach the chamber 10 which has an inlet mouth and an outlet mouth which are always open and heated perimetric walls which connect the open mouths, and the trimmings pass continuously through the chamber, solidifying the outer shell G, so that they leave the chamber 10 as a continuous semisolid that can be subsequently cut into parts. '

In the latter case, the chamber 10 has a re- closable outlet mouth: when the outlet mouth is closed,

16 the chopped trimmings R are introduced into the chamber 10 through the open inlet mouth; the inlet mouth is closed and the trimmings are optionally pressed (for example by means of a piston or similar device) ; the chamber 10 is heated to cause the adhesion of the trimmings R, which form the shell G described above; the outlet mouth of the chamber 10 is then opened and the. tile MR of trimmings (having pre-established dimensions) is expelled, for example by gravity or by means of the same piston.

To summarize the method object of the invention, which is implemented in the plant 1 described above, in order to establish the concepts, this comprises the step of sending at least one trimming R by means of a flow of air, towards a shearing area of the same; said shearing is effected with the use of at least three blades: at least one rotating blade and one fixed blade or two rotating blades and one fixed blade.

Independently of or combined with the previous step, the method also advantageously comprises the step of shearing the trimmings, the step of hot compacting the chopped trimmings into tiles (if envisaged) .

The latter step comprises the following phases:

storing a plurality of chopped trimmings in a heating chamber,

17 heating the chopped trimmings to a temperature at which the chopped trimmings adhere to each other, and optionally:

pressing the chopped and heated trimmings to produce one or more compact tiles.

or alternatively - creating a continuous tube of compacted trimmings at the outlet, of the heating chamber and subsequently cutting it into sections having the desired size.

The objectives indicated above have therefore been achieved .

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