CH674475A5 - - Google Patents

Description

DESCRIPTION

The present invention relates to a method for treating a heterogeneous product, that is to say any product formed from at least two components, such as household waste, said treatment involving the separation of one of the other of said components.

As we know, household waste is generally made up of two main categories of materials.

There are first of all inert or not very fermentable materials, that is to say materials which do not evolve at all or little over time, such as textiles, synthetic organic materials said below more simply plastics, glass and metals.

Then there are non-synthetic or fermentable organic materials, that is to say materials which, according to a more or less slow degradation process, evolve over time.

These include paper, cardboard, plant materials and animal materials.

Thanks to this second category of materials, household waste presents a significant interest in agriculture, as organic amendment products, and that is why they are now more and more systematically subject to a certain recovery.

However, in order to best meet the requirements in terms of agriculture, treatment must first be applied to them, on the one hand, to favor a development towards a certain stabilization of the fermentable fraction and, on the other hand, to remove the inert fraction.

Usually, the stabilization of the fermentable fraction is done by composting, for example by arranging in swaths, that is to say in elongated heaps, the material; suitably moistened, to be treated, and turning these swaths at regular intervals alternating with their resting phases.

Also usually, the elimination of inert materials is done by sorting.

In practice, the sorting techniques usually used exploit the physical characteristics which distinguish the materials to be sorted from one another.

In the case of heavy materials, such as glass and metals, their density is taken into account for this purpose.

As regards light materials, such as plastics, these are their dimensions, these materials most often being in the form of more or less large bags or more or less large bottles or sheets.

The corresponding operation is therefore a simple screening operation specific to the separation of such components.

The present invention generally relates to a provision making it possible to optimize this screening operation by exploiting another physical characteristic, namely the mechanical resistance, of the materials treated.

It is in fact based on the observation that, while inert materials, such as synthetic materials, usually have a non-negligible mechanical resistance which is normally preserved over time, it is not the same for fermentable materials, either that these have a relatively poor mechanical resistance from the start, or that, by reason of their humidification and their evolution by fermentation, this mechanical resistance gradually degrades over time.

The present invention firstly relates to a method for treating a heterogeneous product defined by claim 1.

It also relates to a shredder suitable for the implementation of such a method, this shredder being characterized in that it comprises a drum which, rotatably mounted on a frame, being arranged transversely at the downstream end of a conveyor, has a diameter at least equal to 1 m and carries projecting fingers.

Applied to household waste, the shredding thus characteristic of the invention is selective, because, in practice, taking into account their own mechanical resistance, it essentially only affects the fermentable materials which they contain.

In practice, and experience confirms, synthetic materials only slightly moistening during composting and, on the contrary, essentially retaining their mechanical strength, shredding carried out according to the conditions of the invention does not affect them. that little and their size remains important, while the fermentable materials, them, shred quickly and therefore quickly see their size decrease significantly, their humidification, which is strong, given their great absorption power, quickly leading to degradation of their own mechanical strength.

Thus, the selective shredding according to the invention, which is in fact similar to a simple crushing, is already distinguished, by itself, from a grinding which would indifferently affect all of the materials treated.

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A fortiori, it is distinguished from a grinding which would systematically reduce these in debris without distinction of the same dimensions for all.

As indicated, the shredder drum used for this purpose has a diameter at least equal to 1 m, or even greater than such a dimension.

The diameter of this drum is therefore, according to the invention, relatively large.

Preferably, as regards the treatment of household waste, the speed of rotation applied to it remains, on the contrary, moderate.

In practice, this speed of rotation is less than 500 rpm, for example being of the order of 200 to 300 rpm, so that the inert materials to be eliminated are not effectively affected by the operation of corresponding shredding.

In any case, it is much lower than the usual rotational speeds of the crushers, which themselves are always greater than 500 rpm, for example being of the order of 1000 to 1500 rpm.

Thus, as sought after, only the fermentable materials are concerned by the shredding operation, and the particle size thereof is thus progressively reduced to a relatively small value, such as to facilitate selection during the screening operation. later.

The organic matter content of the compost finally obtained is therefore advantageously raised.

At the same time, the implementation, according to the invention, for the shredder, of a drum of relatively large diameter avoids that, by winding around this drum, the synthetic materials in sheet or in bag gradually come to obscure all or part this, at the expense of its effectiveness.

Experience shows, in fact, that the presence in household waste of such synthetic material having a length greater than the development of a circumference of diameter greater than 1 m is almost excluded.

With regard to the composting of household waste, the shredding operation according to the invention is advantageously associated with an operation for taking up such a material, such as that necessary for turning over a swath, or that intervening between a hopper feed and a refining chain.

Indeed, in both cases, the corresponding shredder fits perfectly into the logic of the corresponding processing process.

In the case of household swath (s), it facilitates the reversal, the conveyor at the downstream end of which is disposed transversely its drum then forming the floor of a vehicle whose chassis carries the frame of this drum and whose mobility allows the reconstruction to the advancement of such a swath.

And, in the case of household refuse in the hopper, it facilitates the rotting before ripening.

In practice, several passages of household waste in such a shredder are provided, a first passage ensuring for example the preparation thereof, while several subsequent passages are, as indicated, each associated respectively with a cycle of their composting.

In all cases, whether the densimetric sorting necessary for the elimination of heavy materials occurs before such passages, after these passages, or between two of them, the final sorting by screening makes it possible to obtain the separation into two components of the treated household waste, namely a component consisting of inert refuse to be eliminated and a component constituting a quality compost particularly rich in organic matter.

In practice, the organic matter content of this compost can, thanks to the invention, usually be advantageously greater than at least 65%.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:

Figure 1 is a perspective view of a shredder according to the invention, shown installed on a vehicle;

Figure 2 is a side view, along arrow II of Figure 1; Figure 3 is a partial elevational view, along arrow 5 III of Figure 2;

Figure 4 shows, on a larger scale, the detail of Figure 3 identified by an insert IV thereon;

Figure 5 is a partial view in cross section along the line V-V of Figure 4;

FIG. 6 is a diagram illustrating the results obtained with the shredder according to the invention;

Figure 7 is a side view, which, similar to that of Figure 2, relates to an alternative embodiment.

In the embodiment illustrated in these figures, the shredder 10 according to the invention permanently equips a vehicle 11.

This vehicle 11 is for example constituted by a moving floor trailer, that is to say a trailer whose floor consists of a conveyor.

This vehicle 11 not being in itself part of the present invention, it will not be described here.

It will suffice to indicate that the shredder 10 according to the invention is disposed at the downstream end of the conveyor forming the corresponding moving floor.

In practice, it is therefore arranged at the rear end of the vehicle 11 concerned.

Overall, the shredder 10 according to the invention comprises, rotatably mounted on a frame 12 itself carried by the chassis 13 of such a vehicle 11, a drum 14, whose diameter D is at least equal to 30 1 m, and which carries projecting fingers 15.

In the embodiment shown, the frame 12 comprises two lateral uprights 16, which are suitably secured, at their lower part, to the chassis 13 of the vehicle 11, for example by buttoning, and which, at their upper part, are connected to the one to the other 35 by a crosspiece 17.

The lateral uprights 16 and the crosspiece 17 can for example be produced using sections of box profile, as shown.

Alternatively, it may as well be U-shaped irons.

40 Anyway, the lateral uprights 16 each carry the bearings 18 necessary for supporting the drum 14, and the installation of the assembly on the chassis 13 of the vehicle 11 is such that, with its fingers 15 , this drum 14 is situated largely above the conveyor forming the moving floor of this vehicle 11, at a distance of for example of the order of 10 cm from it, being of course arranged transversely to this conveyor.

In the embodiment more specifically represented in FIGS. 1 to 5, two lateral deflectors 20, for example of metal, are provided, which, each respectively, are integral with the 50 corresponding lateral uprights 16, an upper cowling 21, which , integral with the crosspiece 17, is, in practice like the latter, inclined to the horizontal, approaching the moving floor of the vehicle 11 towards the front thereof, and a lower sheet protection 22, which, suspended from the lower part of the assembly, is designed to protect the rear axle of such a vehicle 11 from possible projections.

The assembly of the assembly, which can for example be done by welding, is within the skill of the art, and it will therefore not be written in detail here.

60 Similarly, according to provisions relating to those skilled in the art, the side deflectors 20 and / or the upper cover 21 can, if desired, be reinforced by stiffeners.

Preferably, and as shown schematically by a broken line in Figures 1 and 2, the lower part of the deflectors is removable, 65 to facilitate access to the shaft 24 of the drum 14, for example for cleaning.

Externally, the shaft 24 of the drum 14 carries, laterally, at one of its ends, a pinion 25 over which a chain has passed

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26 also passed in an endless loop on a drive pinion

27 integral with it, any motor shaft 28.

Internally, each of the side deflectors 20 carries, projecting around the corresponding end of the drum 14, a mudguard 30, which, for example formed from a simple flat iron suitably attached by welding to such a side deflector 20, is intended to protect the shaft 24 of said drum 14 from any winding of product.

If the diameter D of the drum 14 is, according to the invention, at least equal to 1 m, for example being precisely equal to 1 m, its length L is indifferent.

In practice, it is obviously adapted to the width of the vehicle 11 concerned.

It is therefore for example of the order of 2 m.

Of course, these numerical values are given here only by way of example, and they are not necessarily limiting of the invention.

It is the same for the other numerical values which will be given later.

In practice, the fingers 15 of the drum 14 are arranged in rows, according to generatrices thereof.

In the embodiments shown, eight rows of fingers 15 are thus provided, being regularly distributed circularly around the axis of the drum 14, and, from one row to another, the fingers 15 are alternated.

In practice also, the fingers 15 of the same row are carried by a bar 32, which is common to them and which is removably attached to the drum 14.

For example, and as shown, a bar 32 thus carrying a row of fingers 15 is slidably engaged with slides 33, which, formed in practice of simple jumpers, are integral with the drum 14 by being staggered from place to place. along the corresponding generatrix thereof, and, for its longitudinal retention on the drum 14, there is provided, at at least one of the ends of such a bar 32 and, preferably, at one and the 'other of its ends, suitable stop means, for example bolts with locknuts.

In the embodiment shown, each bar 32 thus implemented thus carries seventeen fingers 15, and the space between the latter is of the order of 10 cm.

Preferably, and as shown, the fingers 15 are each inclined in the same direction relative to the radial direction R of the drum 14 passing through their root, away from this radial direction R on the upstream side thereof. relative to the direction of rotation of this drum 14.

This direction of rotation has been identified by an arrow F in FIGS. 2 and 5.

In practice, this is clockwise.

The angle of inclination of the fingers 15 relative to the corresponding radial direction R is between 0 and 90 °.

For example, it is close to 45 °, as shown.

Either way, it's the same for all 15 fingers.

In the embodiment shown, each of these fingers 15 is in the form of a plate with a parallelepiped contour whose plane extends transversely relative to the axis of the drum 14.

In practice, this is a metal plate.

Its thickness is for example of the order of 1 cm.

Anyway, these fingers 15 are suitably attached to the bar 32 which carries them, for example by welding, and the height of the projection which they form on the surface of the drum 14, and which is the same for all , is, of course, lower, support bar 32 and slide 33 included, at the distance separating this drum 14 from the moving floor of the vehicle 11.

This height, therefore, is in this case less than 10 cm.

Finally, in the embodiment more specifically shown in FIGS. 1 to 5, the drum 14 still carries, along a generatrix, between two bars 32, a U-shaped iron 35 suitable for guiding a cutting blade, if the setting implementation of such a cutting blade is necessary because of a partial winding of any material around the drum 14.

In service, and with regard for example to the reversal of a swath, any recovery machine attacks this swath and pours the material onto the moving floor of the vehicle 11, which, according to arrow F 'in FIG. 2, the then systematically directs, for its discharge, towards the rear of the latter.

In passing, this material is worked by the fingers 15 of the drum 14 of the shredder 10 according to the invention.

As will be noted, it follows from the direction of clockwise rotation of this drum 14 that these fingers 15 work against the current.

In practice, they essentially ensure the shredding of only the fermentable materials of the material worked, without appreciably affecting the synthetic materials contained therein.

It also results from the proper inclination of the fingers 15, which are in some way "leaky" in relation to the material through which they pass, that the tendency that they may have to inadvertently entrain plastic materials from this, at the risk of favoring their winding around the drum 14, is minimized, these synthetic materials falling more easily, by gravity, thanks to this obliquity, before reaching the som-mital part of said drum 14.

Due to the advance of the vehicle 11, the swath worked reconstitutes itself upon leaving it.

In practice, it is preferably applied several passages of the shredder according to the invention to the mass of such a swath.

For example, the sequence of steps in the overall treatment of household waste constituting such a swath can be as follows:

- A first passage, of preparation, in the shredder 10 according to the invention;

- the elimination, by densimetric sorting, of the heavy materials initially present;

- Three new successive passages in the shredder 10 according to the invention, alternating with rest phases, of the order for example of a week;

- the elimination, by a screening operation, of bulky synthetic materials still present.

However, as a variant, the densimetric sorting can also take place from the outset, or, on the contrary, be carried out after screening.

It turns out, in the latter case, that, among the heavy materials concerned, the glass retains in any case a particle size sufficient for such a densimetric sorting to remain effective.

The results obtained are illustrated by the diagram in FIG. 6.

On this one, which relates to the particle size analysis of a compost, the treatment process of which involved three successive passages in a shredder according to the invention, are plotted on the abscissa the dimension, in millimeters for example, of the mesh of the sieve used for the screening operation of this treatment process and, on the ordinate, the percentage, by dry weight, of the products retained on such a sieve.

Curves I and Y relate to light and bulky synthetic materials, curve I for an average circumferential speed at the tips of the fingers 15 of the drum 14 equal to 375 m / min, and the curve I for an average circumferential speed at the tip of these fingers 15 equal to 750 m / min.

Curves II and II 'relate, under the same conditions, to the desired organic materials, that is to say non-synthetic or fermentable organic materials, and curves III, III' to heavy materials, ie, for the essential, by the glass.

For a square mesh of 20 mm side for example, almost all, more than 95%, of synthetic materials is retained, whatever the speed of rotation of the drum 14, while 45% of fermentable materials pass when this speed is 100 rpm, i.e. 325 m / min at the tip of the fingers 15, and 60% when it is 200 rpm, or 750 m / min at the tips of the fingers 15, and that passes jointly in both cases almost all, or 90%, of the glass.

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These results, which relate only to a particular case given here by way of example, show that the shredding according to the invention facilitates the selection of the fermentable materials sought, because while reducing their particle size, it leaves that of synthetic materials almost unchanged. to eliminate, and that, from a certain point of view, it is advantageous to increase the working speed of the drum of the shredder used.

However, in practice, an increase in this working speed risks inadvertently extending the effects of the corresponding shredding to light and bulky synthetic materials.

This is why, according to the invention, it is preferably limited to at most 1800 m / min at the tip of the fingers 15, being preferably of the order of 750 to 110 m / min, and, for example, close to 1000 m / min.

In the variant of implementation illustrated by FIG. 7, the drum 14 of the shredder 10 according to the invention is arranged in the shelter of a cover more developed than previously.

In practice, in this embodiment, this cover comprises a rigid part 38 which, at the rear of the upper cover 21 and the side deflectors 20, is attached to the canopy.

The cover further comprises, laterally, suspended alongside this rigid part 38 as well as from the side deflectors 20 to which it follows, flaps 39, made of flexible material.

Flaps 40 are provided, similarly at the rear, along the upper end edge of the rigid part 38.

To facilitate access, if desired, to the drum 14, at least some of these flaps 39, 40, or even all of these, can be removable.

For example, their suspension is very simple using screw-nut assemblies.

In addition, in the embodiment shown, a flap 42 is also provided at the front, along the corresponding edge of the upper cover 21.

Finally, in this embodiment, a cover is also provided around the transmission ensuring the connection between the shaft of the drum 14 and the corresponding drive shaft.

Of course, the present invention is not limited to the embodiments described and shown, but encompasses any variant.

In particular, although preferably implemented on a vehicle or other mobile machine, when it comes to the treatment of household waste whose composting is done in windrows, the shredder according to the invention can just as easily equip a fixed installation, and this can be more particularly the case when it comes to household waste to be passed from a storage hopper to a processing line.

Of course also, the field of application of the invention is not necessarily limited to that of household waste only, but it extends more generally to that of any other heterogeneous material formed from a mixture products whose stiffness is not likely to hinder the operation of the shredder to be used.

2 sheets of drawings

Claims (13)

674475 2 1. A method of treating a heterogeneous product involving the application to it of a screening operation with a view to separating it into two components, characterized in that said screening operation is preceded by an operation of shredding carried out so as to selectively affect said components, the shredding being carried out along a circular path exceeding 3 m using protruding fingers carried by a rotary drum. 2. Method according to claim 1, characterized in that, with regard to the composting of household waste, the method comprises an operation for taking up the heterogeneous product such as that necessary for turning over a swath, or that intervening between a hopper feed and a refining chain. 3. Shredder suitable for implementing the method according to any one of claims 1 and 2, characterized in that it comprises the drum (14) which, rotatably mounted on a frame (12) being arranged transversely to the the downstream end of a conveyor has a diameter at least equal to 1 m and carries projecting fingers (15). 4. Shredder according to claim 3, characterized in that the fingers (15) all have the same length. 5. A shredder according to any one of claims 3 and 4, characterized in that the fingers (15) are arranged in rows along generatrices of said drum (14). 6. A shredder according to claim 5, characterized in that, from one row to another, the fingers (15) are alternated. 7. A shredder according to any one of claims 5 and 6, characterized in that the fingers (15) of the same row are carried by a bar (32) which is common to them and which is removably attached to said drum (14). 8. Shredder according to claim 7, characterized in that a bar (32) carrying a row of fingers (15) is slidably engaged with slides (33) integral with the drum (14). 9. A shredder according to any one of claims 3 to 8, characterized in that the fingers (15) are each inclined in the same direction relative to the radius (R) of the drum (14) and on the upstream side relative to the direction of rotation of said drum (14). 10. A shredder according to any one of claims 3 to 9, characterized in that each of the fingers is in the form of a wafer with a parallelepiped outline. 11. A shredder according to any one of claims 3 to 10, characterized in that the conveyor at the downstream end of which is disposed the drum (14) is intended to form the floor of a vehicle (11). 12. A shredder according to any one of claims 3 to 11, characterized in that the drum (14) is protected by a cover. 13. A shredder according to any one of claims 3 to 12, characterized in that the average circumferential speed of the tip of the fingers (15) is limited to at most 1800 m / min and is preferably of the order of 750 at 1100 m / min.