FR2604924A1 - PROCESS FOR TREATING A HETEROGENEOUS PRODUCT, IN PARTICULAR HOUSEHOLD GARBAGE, AND A CLEANER SPECIFIC TO THE IMPLEMENTATION OF SUCH A METHOD - Google Patents

Abstract

THIS IS THE TREATMENT OF ANY HETEROGENEOUS MATERIAL INVOLVING THE APPLICATION TO IT OF A SCREENING OPERATION WITH A VIEW TO SEPARATING IT INTO TWO COMPONENTS. FOLLOWING THE INVENTION, THE SAID SCREENING OPERATION IS PRECEDED BY ONE OR MORE PASSES OF THE MATERIAL TO BE TREATED IN A SHREDDER 10 CLEAN TO INTERVENE SELECTIVELY ON THE COMPONENTS OF THE LATTER. APPLICATION, ESPECIALLY, TO COMPOSTING HOUSEHOLD GARBAGE.

Description

"Process for treating a heterogeneous product, in particular garbage

  The present invention relates generally to the treatment of any heterogeneous product, that is to say of any product formed from the same process. least two components, said treatment involving the separation of the said components from one another, and more particularly, but not necessarily exclusively, the case where the product to be treated

  consists of household waste.

  As we know, garbage is generally composed of two major categories of materials. First of all there are inert or little fermentable materials, that is to say materials that do not evolve at all or little over time, such as, for example, textiles, so-called synthetic organic materials. hereinafter more simply synthetic materials, glass, and

metals.

  Then there are non-synthetic or fermentable organic materials, that is to say materials which, following 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, garbage is of considerable importance in agriculture as organic products of amendment, and that is why they are now more and more

  systematically the object of some recovery.

  But, in order to best meet the requirements in this field of agriculture, it is first necessary to apply a treatment to them, on the one hand to promote a development towards a certain stabilization of the fermentable fraction, and on the other hand to withdraw the inert fraction. Usually, the stabilization of the fermentable fraction is done by composting, for example by arranging in windrows, that is to say in elongated heaps, the material, suitably moistened, to be treated, and returning these swaths in regular time. alternating with

rest phases of these.

  Also common, the elimination of

  inert materials is done by sorting.

  In practice, the sorting techniques usually used exploit the physical characteristics that

  distinguish between the materials to be sorted.

  With regard to heavy materials, such as for example glass and metals, it is their density which is

effect taken into account.

  As regards light materials, such as for example plastics, it is their dimensions, these materials being most often in the form of more or less significant bags or bottles or more leaves or

less big.

  The corresponding operation is therefore a simple screening operation specific to the separation of such components. The present invention generally relates to an arrangement for optimizing this screening operation, exploiting another physical characteristic, namely the mechanical strength, of the treated materials. It is indeed based on the observation that, if inert materials, such as synthetic materials, usually have a significant mechanical resistance that is normally preserved over time, it is not the same for fermentable materials, either that these have from the beginning a relatively poor mechanical strength, or that, because of their humidification and their evolution by fermentation, this mechanical resistance deteriorates progressively in

the weather.

  More specifically, the subject of the present invention is firstly a method of treating a heterogeneous product, of the kind involving the application to this product of a screening operation with a view to separating it into two components. method being generally characterized in that said screening operation is preceded by a shredding operation conducted so as to selectively affect said components; it also has for object a shredder suitable for the implementation of a

such a method.

  Applied to household waste, shredding thus characteristic of the invention is selective, because, in practice, given their own strength, it essentially affects only materials

  fermentable that these contain.

  In practice, and the experiment confirms it, the materials of synthetic material only wet slightly during the composting and maintaining on the contrary for the most part their mechanical resistance, a shredding practiced according to the conditions of the invention does not affect them that small and their size remains important, while the fermentable materials, they, shred quickly and therefore quickly see their size decrease significantly, their humidification, which is strong, given their high absorption capacity, leading quickly to a degradation of their own mechanical resistance. Thus, the selective shredding according to the invention is already distinguished, by itself, from a grinding which

  would affect indifferently all the treated materials.

  A fortiori, it differs from a grinding that would systematically reduce them into debris

  indistinctly of the same dimensions for all.

  In practice, the shredder used for this purpose comprises a drum, which is rotatably mounted on a frame, whose diameter is at least equal to 1 m, or even greater than such a dimension, and which projects fingers. The diameter of this drum is, therefore, following

the invention, relatively large.

  Preferably, with regard to the treatment of household waste, the speed of rotation applied to it remains it, on the contrary, moderate. In practice, this rotational speed is less than 500 rpm, being for example of the order of 200 to 300 rpm, so that the inert materials to be eliminated are effectively not significantly affected by

  the corresponding shredding operation.

  In any case, it is well below the usual rotational speeds of the mills, which, they are always greater than 500 rpm, being for example of the order of

1000 to 1500 rpm.

  Thus, as desired, only the fermentable materials are involved in the shredding operation, and the particle size thereof is thus progressively reduced to a relatively low value, such as to facilitate selection during the operation of

subsequent screening.

  The organic matter content of the compost finally

  obtained is therefore advantageously raised.

  Together with the implementation, according to the invention, for the shredder, of a drum of relatively large diameter, prevents that, by winding around this drum, the synthetic materials in sheet or bag do not come gradually to obscure in all or

  part of it, to the detriment of its efficiency.

  Experience shows, in fact, that the presence in the household waste of such synthetic materials 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 refuse, the shredding operation according to the invention is advantageously associated with a recovery operation of such a material, such as that required for the reversal of a swath, or that taking place between a hopper power

and a ripening chain.

  Indeed, in either case, the corresponding shredder fits perfectly in the logic of the corresponding processing process. As a household garbage swath (s), it facilitates the turnaround, its drum is then preferably disposed transversely to the downstream end of a conveyor forming the floor of a vehicle whose frame carries the frame of this drum and whose mobility allows the

  reconstitution to the progress of such windrow.

  And, in the case of household waste in a hopper,

  facilitates crumbling 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, associated

  each respectively to a cycle of their composting.

  In all cases, that the densimetric sorting necessary for the removal of heavy materials takes place before such passages, after these passages, or between two of these, 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 rejects to be removed, and a component constituting quality compost

  particularly rich in organic matter.

  In practice, the organic matter content of this compost can, thanks to the invention, be usually

  advantageously greater than at least 65%.

  The characteristics and advantages of the invention

  will emerge from the description which follows,

  by way of example, with reference to the appended diagrammatic drawings in which: FIG. 1 is a perspective view of a shredder according to the invention, shown installed on a vehicle; Figure 2 is a side view along the arrow II of Figure 1; Figure 3 is a partial elevational view along the arrow III of Figure 2; FIG. 4 shows, on a larger scale, the detail of FIG. 3 indicated by an inset IV thereon; Figure 5 is a partial cross-sectional view along the line V-V of Figure 4; Figure 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 form of implementation illustrated in these figures, the shredder 10 according to the invention equips

remains a vehicle 11.

  This vehicle 11 is for example constituted by a trailer with moving floor, that is to say a trailer whose

  floor is constituted by a conveyor.

  This vehicle 11 is not 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 disposed at the end

rear of the vehicle 11 concerned.

  Overall, the shredder 10 according to the invention comprises, rotatably mounted on a frame 12 itself carried by the frame 13 of such a vehicle 11, a drum 14, whose diameter D is at least 1 m, and which door protruding

fingers 15.

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

crosses 17.

  The lateral uprights 16 and the crossmember 17 may for example be made using sections of profiled section.

box, as shown.

  Alternatively, it may as well be irons U. Anyway, the side uprights 16 each carry respectively the bearings 18 necessary for the support of the drum 14, and the implementation of all on the chassis 13 of the vehicle 11 is such that, with its fingers 15, this drum 14 is situated above the conveyor forming the moving floor of this vehicle 11, at a distance for example of the order of 10 cm from this ci, being well

  heard arranged transversely with respect to this conveyor.

  In the embodiment more specifically shown in FIGS. 1 to 5, two lateral deflectors 20, of metal for example, are provided, each of which, respectively, is secured to the corresponding lateral uprights 16, an upper cowling 21 which, secured to the cross member 17, is, in practice in the image thereof, inclined to the horizontal, approaching the moving floor of the vehicle 11 in the direction of the front thereof, and a bottom plate of protection 22, which, suspended on the lower part of the assembly, is intended to protect any

  projections the rear axle of such a vehicle 11.

  The assembly of the assembly, which can for example be done by welding, is within the skill of the art, and it will not

so not described in detail here.

  Similarly, according to the provisions of the art, the side baffles 20 and / or the upper cowl 21 may, 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 baffles is removable, to facilitate access to the tree

  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 on which is passed a chain 26 also passed in endless loop on a drive gear 27 secured to it,

of any motor shaft 28.

  Internally, each of the lateral deflectors 20 protrudes around the corresponding end of the drum 14, a mudguard 30, which, for example, is formed of a simple flat iron suitably attached by welding on such a lateral deflector 20, is meant to protect from everything

  product winding the shaft 24 of said drum 14.

  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 for example of the order of 2 m.

  Of course, these numerical values are only given here as examples, 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, following 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 simple jumpers, are integral with the drum 14 being staggered from place to place on the along the corresponding generatrix thereof, and, for its longitudinal retention on the drum 14, is provided at at least one end of such a bar 32 and, preferably, to one and the other of its ends, appropriate stop means, for example bolts with locknuts. In the embodiment shown, each bar 32 thus implemented thus carries seventeen fingers

  , and the space between them 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 of

  it with respect to the direction of rotation of this drum 14.

  This direction of rotation was marked by an arrow F on

Figures 2 and 5.

  This is in practice the clockwise direction.

  The angle of inclination of the fingers 15 with respect to the corresponding radial direction R is between 0 and 90. For example, it is close to 45 ', as shown. Anyway, it's the same for all

fingers 15.

  In the embodiment shown, each of these fingers 15 is in the form of a wafer with a parallelepipedal outline whose plane extends

  transversely to the axis of the drum 14.

  This is in practice a metal plate.

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

  Anyway, these fingers 15 are properly reported on the bar 32 which carries them, for example by welding, and the height of the projection they form on the surface of the drum 14 is, of course, lower, bar support 32 and slide 33 included, at a distance

  separating this drum 14 from the moving floor of the vehicle 11.

  This height, therefore, is, in this case, less than cm. Finally, in the embodiment more specifically shown in FIGS. 1 to 5, the drum 14 still carries, according to a generatrix, between two bars 32, a U-shaped iron 35 capable of guiding a cutting blade if the setting of such a cutting blade is necessary because of a partial winding of any

materials around the drum 14.

  In use, and for example involving the overturning of a windrow, any machine engages this windrow and pours the material on the moving floor of the vehicle 11, which, following the arrow F 'of Figure 2 , then directs it systematically, for its spill, towards

the back 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 are working to

against current.

  In practice, they essentially ensure the shredding of the only fermentable materials of the material worked, without substantially affecting the materials

  in synthetic material contained therein.

  It also results from the proper inclination of the fingers 15, which are in a way "elusive" with respect to the material they pass through, that the tendency they may have to cause the materials of synthetic material to be inadvertently -ci, at the risk of promoting their winding around the drum 14, is minimized, these materials in synthetic material falling more easily, by gravity, thanks to this obliquity, before

  reaching the summit portion of said drum 14.

  Due to the advance of the vehicle 11, the windrow worked is reconstituted by itself at the exit of

this one.

  In practice, it is preferentially applied several passages of the shredder according to the invention to the

mass of such windrow.

  For example, the sequence of steps of the overall treatment of garbage constituting such windrow may be the following: - a first pass, of preparation, in the shredder 10 according to the invention; - 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 one week; the elimination, by a screening operation, of the

  bulky synthetic materials still present.

  But, alternatively, the densimetric sorting can be done from the beginning, or, on the contrary, be

practiced after the screening.

  It turns out, in the latter case, that among the heavy materials concerned, the glass retains in any case a sufficient size for such sorting

Density remains effective.

  The results obtained are illustrated by the diagram

of Figure 6.

  On the latter, which concerns the particle size analysis of a compost whose treatment process has involved three successive passes in a shredder according to the invention, are given, on the abscissa, the dimension, in mm for example, of the mesh. sieve used for the screening operation of this treatment process, and on the ordinate the percentage, by dry weight, of the products retained on a

such sieve.

  Curves I and I 'refer to light and bulky synthetic materials, curve I to average circumferential speed at the tip of fingers 15 of drum 14 equal to 375 m / min, and curve I' to average circumferential speed at the tip of these fingers

equal to 750 m / min.

  The 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 the curves III, III' to the materials

  heavy, or, for the most part, glass.

  For a square mesh of 20 mm for example, almost all, or more than 95%, of synthetic materials is retained, regardless of the speed of rotation of the drum 14, while spend 45% of the fermentable materials when this speed is rpm, 325 m / min at the tip of the fingers 15, and 60% when it is 200 rpm, or 750 m / min at the tip of the fingers 15, and that, jointly, passes, in one and

  the other case, almost all, or 90%, of the glass.

  These results, which only concern a particular case given here by way of example, show that the shredding according to the invention facilitates the selection of the desired fermentable materials, because while reducing their ganulometry, it leaves almost unchanged that of synthetic materials. to eliminate, and that, from a certain point of view, there is interest in increasing the speed of

  work of the shredder drum implemented.

  But, in practice, an increase in this speed of work may inadvertently extend the effects of the corresponding shredding to light and bulky synthetic materials. Therefore, according to the invention, it is preferably limited to at most 1800 m / min at the tip of the fingers 15, preferably being of the order of 750

  at 1100 m / min, and, for example, close to 1000 m / min.

  In the variant embodiment illustrated in FIG. 7, the drum 14 of the shredder 10 according to the invention is arranged in the shelter of a cowling more

developed only previously.

  In practice, in this embodiment, this cowling comprises a rigid portion 38, which, at the rear of the upper cowling 21 and the lateral baffles 20, is

reported in awning on these.

  The cowling furthermore comprises, laterally, suspended at the sides of this rigid part 38, as well as at the lateral deflectors 20 to which it follows,

bibs 39, of flexible material.

  Mud flaps 40 are similarly provided at the rear along the upper end edge of

the rigid part 38.

  To facilitate access, if desired, the drum 14, at least some of these flaps 39, 40, or even the

  all of them, can be removable.

  For example, their suspension is very simply

using screw-nut sets.

  Furthermore, in the embodiment shown, there is also provided a flap 42 at the front, along

  the corresponding slice of the upper cowling 21.

  Finally, in this embodiment, a cowling is also provided around the transmission ensuring the connection between the shaft of the drum 14 and the motor shaft

corresponding.

  Of course, the present invention is not limited to the embodiments described and shown, but

  encompasses any variant of execution.

  In particular, although preferably implemented on a vehicle or other mobile machine, when it comes to the treatment of household waste composting is in windrows, the shredder according to the invention can equally well equip an installation this is particularly the case when it comes to household waste to transit from a storage hopper to a

processing chain.

  Of course, also, the field of application of the invention is not necessarily limited to that of household garbage alone, but it extends more generally to that of any other heterogeneous material formed of a mixture of products whose rigidity is not likely to impede the functioning of the

shredder & implement.

Claims (14)

  A method of treating a heterogeneous product involving the application thereof to a screening operation for the purpose of separating it into two components, characterized in that said screening operation is preceded by an operation of shredding driving way   selectively assigning said components.   2. Method according to claim 1, characterized in that, in the case of composting household waste, the shredding operation is associated with a recovery operation of such a material, such as for example that necessary for the reversal of 'a swath, or intervening between   a feed hopper and a ripening chain.   3. Process according to any one of   Claims 1, 2, characterized in that one drives   the shredding operation using a shredder (10) having a rotating drum (14) whose diameter is at   less than 1 m and projecting fingers (15).   4. Shredder specific to the implementation of the process   according to any one of claims 1 to 3,   characterized in that it comprises, rotatably mounted on a frame (12), a drum (14) whose diameter is at least equal to   1 m and projecting fingers (15).   5. Shredder according to claim 4, characterized in that the fingers (15) of its drum (14) are arranged in rows along generatrices of said drum (14).   6. Shredder according to claim 5, characterized in that, from one row to another, the fingers   (15) of its drum (14) are alternated.   7. Shredder according to any one of   Claims 5, 6, characterized in that the fingers (15)   the same row of its drum (14) are carried by a rod (32) which is common to them and which is reported from   removably on said drum (14).   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. Shredder according to any one of   Claims 4 to 8, characterized in that the fingers (15)   of the drum (14) are each inclined in the same direction relative to the radial direction (R) of such a drum (14) passing through their roots, away from this radial direction (R) on the upstream side of that in relation to the meaning of rotating said drum (14).   10. Shredder according to any one of   Claims 4 to 9, characterized in that each of   fingers of the drum (14) is in the form of a   wafer with parallelepipedic contour.   11. Shredder according to any one of   Claims 4 to 10, characterized in that the drum (14)   is disposed transversely at the downstream end of a conveyor. 12. Shredder according to claim 11, characterized in that the conveyor forms the floor of a vehicle (11) whose frame (13) carries the frame (12) of its drum (14).   13. Shredder according to any one of   Claims 4 to 12, characterized in that its drum   (14) is disposed away from a cowling.   14. Shredder according to any one of   Claims 4 to 13, characterized in that the speed   circumferential circumference of the tip of the fingers (15) of its drum (14) is limited to at most 1000 m / min by being   preferably of the order of 750 to 1100 m / min.