DE8713688U1 - Shredders for treating non-uniformly composed products, especially household waste - Google Patents

Description

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Shredder for handling non-uniformly composed

Products/ especially household waste 5

The innovation generally concerns a shredder for the treatment of any non-uniformly composed products*, i.e. products that consist of at least two components. The shredder provides for the separation of the said components from one another.

The innovation is particularly, but not necessarily exclusively, directed at the case where the product to be treated is household waste.

As is well known, household waste, generally speaking, consists of two large groups of substances.

First of all, these are the non-attackable, inert or poorly decomposable materials, i.e. materials that do not change or change only slightly over time, for example textiles, synthetic organic materials, which for the sake of simplicity are referred to as plastics below, glass and metals.

There are also non-synthetic organic or decomposable substances, i.e. substances that change over time during a more or less lengthy decomposition process.

These include in particular paper, cardboard, plant and animal substances.

Because of this second type of material, domestic waste has a not insignificant value for agriculture as an organic fertilizer, and for this reason a certain amount of recycling is now being systematically carried out on an ever-increasing scale. However, in order to best meet the needs of agriculture, domestic waste must be subjected to treatment, on the one hand to encourage a development towards a certain stabilization of the decomposable part, and on the other hand to separate out the non-decomposable part.

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Usually, the decomposable part is stabilized by composting, for example by depositing the sufficiently moist material in swaths, i.e. in elongated piles, by treating and by shifting the swaths at regular intervals, alternating with letting the swaths rest.

In a manner also known per se, the non-degradable material is removed by sorting.

The sorting methods commonly used exploit the physical properties in which the materials to be sorted differ.

When it comes to heavy materials, such as glass and metal, the different densities of the materials are used for sorting.
When it comes to light materials, such as plastic, the dimensions make the difference, since these materials usually come in the form of more or less large bags or bottles or large or small films.

The appropriate method here is a simple sieving process that is suitable for separating out these components. The subject of the innovation is generally an arrangement for optimizing this sieving process, whereby another physical property is exploited, namely the mechanical strength of the treated materials.

The innovation takes advantage of the observation that, while inert materials, such as plastics, generally have a non-negligible strength that normally remains constant over time, this is not the case for non-decomposable materials, either because they have a relatively low strength from the outset or because the strength gradually decreases over time due to the moisture in the materials and their changes as a result of decomposition.

The subject of the innovation is therefore a shredder for treating products of non-uniform composition, in particular household waste; the shredder is characterized overall by a drum which is arranged rotatably on a frame transversely to the end of a conveyor, has a diameter of at least 1 m and carries projecting fingers.

When treating household waste, the innovative shredder ensures separation, because in practical operation it mainly attacks these substances due to the special strength properties of the decomposable material contained in the household waste.

In practical use, it has been confirmed that plastic materials absorb little moisture during composting and therefore, conversely, their mechanical strength remains essentially unchanged, so that passage through the innovative shredder has little effect on them and they retain their considerable dimensions, while the decomposable materials are quickly shredded and therefore quickly reduce in size considerably, since their strong increase in moisture, thanks to their high absorption capacity, quickly leads to a reduction in their strength.

The innovative selective shredding _, which is actually comparable to a simple crushing, differs fundamentally from a grinding process, which would affect all treated materials indiscriminately.

It differs even more from a grinding process, in which the treated materials were systematically broken down into pieces of the same size.

As mentioned, the drum of the shredder used has a diameter of at least 1 m or more.

The diameter of this drum is therefore relatively large.

In contrast, the speed at which it rotates for treating household waste is relatively low.

In practical operation, the speed is less than 500 rpm and is, for example, in the range of 200 to 300 rpm, so that the non-degradable materials to be separated are not actually significantly damaged in the respective shredding process.

In any case, the speed is significantly lower than in conventional grinders, where it is always above 500 min" and reaches, for example, 1000 to 1500 min" ¹ .

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As explained above, only the decomposable materials are affected by the shredder process and the size of these materials is reduced to a fairly small value, making sorting out during subsequent screening easier. The content of organic materials in the compost finally obtained is therefore advantageously high.

In connection with this, the use of a relatively large drum in the new shredder prevents the foil-like or bag-like plastics from covering the drum and impairing its effectiveness. In practical operation, it has been shown that plastic objects with a length longer than the drum circumference and a diameter of more than 1 m do not occur in household waste.

When treating household waste, the shredding of the waste can be combined with the process of collecting the waste*, e.g. when moving swaths or when feeding &igr; household waste from the bunker to an interim storage facility. In both cases, the innovative shredder is fully integrated into the process of the respective treatment process.

In the case of household waste deposited in windrows, the movement of the waste is made easier by the fact that a conveyor, at the end of which the shredder drum is arranged transversely, forms the base of a vehicle, the chassis of which carries the frame of the drum and the mobility of which enables the re-creation of such a windrow as it advances.

When household waste is stored, it is easier to shred the waste before sorting it.

In practical use, several passes of the household waste through such a shredder are planned, with a first pass serving, for example, to prepare the household waste, while several further passes, as mentioned, are each connected to a phase of waste composting.

In all cases, regardless of whether the sorting by density required to separate heavy materials is carried out before these passes, after the passes or between two passes, the final sorting

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Process 4by sieving a separation of the treated household waste into two components, namely a component that is made up of non-rotting coarse residues that are to be separated out and a component that is a compost with a particularly high proportion of organic matter.

In practical use, the organic matter content of the compost can advantageously generally reach at least 65% when the innovation is applied.

The features and advantages of the innovation will become apparent from the following description of embodiments based on the schematic drawings, which show the following:
Fig.l: a perspective view of a shredder according to the invention mounted on a vehicle? Fig.2: a side view in the direction of arrow II in Fig.l;

Fig.3: a partial view in the direction of arrow III in Fig.2; Fig.4: a section indicated by a mark IV in Fig.3

Detail from this figure on a larger scale; Fig.5: a partial cross-section along the line V-V in Fig.4; Fig.6: a graph showing the results that can be achieved with the shredder according to the innovation; Fig.7: a side view of a modified version of the arrangement according to Fig.2.

In the embodiment shown in the figures, the shredder 10 according to the innovation is permanently mounted on a vehicle 11.

This vehicle 11 is, for example, a trailer with a movable floor, i.e. a trailer whose floor is designed as a conveyor.

Since the vehicle is not part of the innovation, it will not be described in detail here.

It is only intended to show that the new shredder 1Ö is mounted at the discharge end of the conveyor, which represents the moving floor of the vehicle,

Overall, the shredder 10 according to the invention has a frame 12/ which in turn is connected to the chassis 13 of a

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such a vehicle 11, has a rotatably mounted drum 14, the diameter D of which is at least 1 m and which is equipped with projecting fingers 15.

In the embodiment shown, the frame 12 has two side supports 16, which are fastened by their lower part in a suitable manner to the chassis 13 of the vehicle 11, e.g. screwed to it by means of screw connections, and which are connected to one another at their upper ends by a cross member 17.

The side supports 16 and the cross member 17 can, for example, be made from square profile pieces as shown.

Instead, U-irons can also be provided. Independently of this, the side supports 16 each carry a bearing 18 for receiving the drum 14, and the whole is mounted on the chassis 13 of the vehicle 11 in such a way that the drum 14 with its fingers 15 is located well above the conveyor forming the movable floor of the vehicle 11 at a distance of, for example, about 10 cm from the vehicle floor, the drum naturally being arranged transversely to the conveyor.

In the embodiment shown in detail in Figures 1 to 5, two lateral deflection plates 20, made of metal for example, are also provided, which are attached to the respective lateral support 16, an upper cover 21, which is firmly connected to the cross member 17, is inclined to the horizontal practically in the same way as the latter, approaching the movable floor of the vehicle 11 in the direction of the front end, and a lower protective

3Ö plate 22, which is attached to the lower part of the arrangement and is intended to protect the rear axle of the vehicle 11 against any parts thrown in this direction.

The individual parts of the overall arrangement can be welded together or connected in other ways known _to the person skilled in the art.

■#5 'Wisely connected; this will not be described in detail here.

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If necessary, the lateral deflection plates 20 and/or the upper cover 21 can also be reinforced by stiffeners in a manner known per se to those skilled in the art.

As indicated by dashed lines in Figures 1 and 2, the lower portion of the baffles is preferably removable in order to facilitate access to the shaft 24 of the drum 14 when, for example, cleaning work has to be carried out.

The shaft 24 of the drum 14 carries at one end on the outside a pinion 25 over which a chain 26 runs, which also leads as an endless chain over a drive pinion 27 which is firmly connected to any drive shaft 28.

Each side deflector plate 20 carries a protective plate 30 projecting inwardly around the corresponding end of the drum 14, which can consist, for example, of a simple flat plate suitably welded to such a side deflector plate 20; it serves as protection against objects winding up around the shaft 24 of said drum 14.

While the diameter D of the drum is at least 1 m and, for example, exactly 1 m, its length L is of no particular importance.

In practice, of course, it depends on the width of the vehicle in question 11.

The length is therefore approximately 2 m.

Of course, these numbers are given only as examples and do not limit the innovation.

The same applies to the other numerical values listed below.

In practical implementation, the fingers 15 of the drum 14 are arranged in rows on the drum's surface lines. In the embodiment shown, eight rows of fingers 15 are provided in this way; the rows are evenly spaced on a circle around the axis of the drum 14, and the fingers 15 are spaced apart in successive rows.

In practical implementation, the fingers 15 of one and the same row are also supported by a rod 32 which

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1 is common to them and which is detachably attached to the drum 14.

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I For example, a rod 32 carries, as shown, a row of

.- he finger 15 and is sliding in guides 33,

=; 5 which in practice are designed as simple brackets and

the drum 14, being moved from one point to another along the corresponding surface line of the drum

I, and for holding the rods 32 on the

f Drum 14 in the longitudinal direction is at least one end of each

f 10 rod, but preferably at both ends, a levelled

1 impact device provided, for example screw bolts

I with lock nuts.

I In the illustrated embodiment, each

I set stick 32 seventeen fingers 15, and the distance between

t 15 this is on the order of 10 cm.

I Preferably and as shown all fingers are 15 in

I same direction opposite to the direction of the root

i of the finger extending radius R of the drum 14 is inclined, where-.

I with the fingers moving upstream from this radius direction R

I 20 with respect to the direction of rotation of the drum 14.

I The direction of rotation is indicated in Figures 2 and 5 by a

§ Arrow F indicated.

t In the practical version, the direction of rotation is

j ' clockwise.

Jj. ' 25 The angle of inclination of the fingers 15 relative to the corresponding

\ · The corresponding radius direction R has a size between 0 and 90°.

For example, as drawn, it is about 45°. ' In any case, it is the same for all fingers 15.

In the embodiment shown, each finger 15 30 has the shape of a plate with an outline in the form of a parallelpiped, the plane of which is transverse to the axis of the drum.

In the practical version, a metal plate I is provided.

[| 35 The thickness of the plate is, for example, on the order of « 1 dm.

In any case, the fingers 15 are suitably mounted on the rod 32 supporting them, for example welded, and the height by which they protrude from the surface of the drum 14, which is the same for all the fingers, is of course, including the supporting rod 32 and the guide 33, less than the distance between the drum 14 and the moving floor of the vehicle 11.

In the present case the height is less than 10 cm. Finally, the drum 14 in the embodiment shown in detail in Figures 1 to 5 carries a U-iron 35 along a generatrix between two rods 32 for guiding a cutting knife in the event that the use of such a knife proves necessary because some material has partially wrapped around the drum 4. When, for example, a swath is to be moved during use of the arrangement, some loading device picks up the swath and throws the material onto the movable floor of the vehicle 11, which systematically conveys it in the direction of arrow F' in Figure 2 to the rear discharge end of the vehicle.

During the passage, this material is processed by the fingers of the drum 14 of the innovative shredder 10.

As can be seen, the clockwise rotation of the drum 14 means that the fingers 15 work against the current. · " ~

In practice, they essentially ensure the shredding of only the decomposable substances in the treated material, without significantly affecting the synthetic substances contained therein.
Furthermore, the inherent inclination of the fingers 15, which in a sense "avoid" the material through which they pass, means that the tendency for plastic parts to be accidentally pulled out of the material, with the risk of the parts winding up on the drum 14, has become extremely low, since the plastic parts, due to this inclined position of the fingers, fall back more easily under the effect of gravity before they reach the position on the top of the said drum 14.

Due to the forward movement of the vehicle 11, the processed swath automatically re-forms at the exit of the vehicle.

In practical operation, the mass of such a swath preferably passes through the innovative shredder several times*

For example, the following sequence of treatment steps can be provided for the processed household waste that forms such a plume:

= first preliminary shredder 10;

- Separation of the initially present heavy substances by sorting according to density;

- three further consecutive passes through the new shredder 10, alternating with rest periods of the order of magnitude of, for example, one week;

- Remove any remaining large plastic parts by sieving.

Instead, density sorting can also be carried out at the beginning or /conversely, after sieving* In fact, it has been found that in the latter case the glass between the heavy materials in question always retains a piece size that is sufficient to carry out effective density sorting.

The results obtained are shown in the graph Fig.6-:^ -. ~."

There, the conditions for the grain size analysis of a coop are shown, for the treatment of which three consecutive passes through an innovative shredder were carried out; in the abscissa direction, for example, the mesh sizes of a sieve that was used for sieving during the treatment are given in mm, and in the ordinate direction the dry weight content in percent of the materials retained on such a sieve.

Curves I and I * refer to light and voluminous plastic parts, with curve I applying to an average peripheral speed of the tips of the fingers 15 on the drum 14 of 375 m/min and curve I' applying to an average peripheral speed of the tips of the fingers of 750 m/min.

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Curves II and II ¹ refer, under the same conditions, to the organic substances sought, ie to the non-synthetic or decomposable organic substances, and curves III, III ¹ to heavy substances, ie mainly to glass.

For a square mesh of, for example, 20 mm side length, the entire quantity, namely 95% of the plastics, is retained, regardless of the speed of the drum 14, while 45% of the decomposable materials pass through; if the speed is 100 min , that is 325 m/min at the tip of the fingers 15, and 60% at a speed of 200 min , that is 75'D m/min at the tip of the fingers 15* and, in addition, at the same time in both cases almost all the glass, namely 90%, passes through.

■ These results, which concern only one specific case, cited here as an example, show that the innovative shredder facilitates the separation of the desired decomposable materials, because while their size is reduced, the size of the plastics to be separated is not changed, and also show that

From certain points of view it is advantageous to increase the operating speed of the drum of the shredder used. . . .

■ -"._' ' In practical use, however, increasing the operating speed carries the risk that the corresponding shredding effect also extends to light and voluminous plastics.

Therefore, according to the innovation &bull; ' the working speed is preferably limited to a maximum of 1800 m/min at the tip of the fingers 15 by a suitable design of the centrifugal drum, whereby speeds of the order of 750 to 1100 m/min and, for example, about 1000 m/min are preferred.

In the modified version shown in Fig.7, the drum 14 of the new shredder 10 is placed in the protective area of a cover that is larger than in the first version.

In the practical implementation of this modified form, the cover has a rigid part 38 which is attached to the rear of the upper cover 21 and the side cover plates 20 as a protective roof.

The cover also has, on the sides, attached to the sides of the rigid part 38 and to the lateral deflectors 20 which it continues, mud flaps 39 made of flexible material.

Similarly, mud flaps 40 are provided at the rear of the frame at the upper end of the rigid part 38*

In order to facilitate any necessary access to the drum 14, at least some of the dirt traps 39, 40 or even all of the dirt traps can be designed to be removable.

For example, they can be easily attached with screws and ! 15 nuts.
j Furthermore, in the embodiment shown, a

Mud flaps 42 are provided at the front along the corresponding edge of the upper cover 21.

Finally, this design also covers the transmission, which creates the connection between the shaft of the drum 14 and the associated drive shaft*

Of course, the innovation is not limited to the described and illustrated embodiments but also includes all other embodiments. - - - &mdash;_"_-.&mdash;- - 25 ''. In particular, the shredder according to the innovation, if it is also designed for the treatment of domestic waste, the composting of which takes place in swaths, preferably mounted on a vehicle or other mobile machine, can also be designed as a stationary system, and this can be the case in particular when domestic waste is present which is to be transferred from a storage bunker to a treatment belt. &zgr; ' Furthermore, the innovation cannot of course necessarily be

> sometimes only use it for household waste but rather

u generally also for other non-uniform material which is present as a mixture of substances whose strength cannot impair the operation of the shredder to be used.

Claims (11)

Protection claims 1. Shredder for treating non-uniformly composed products, in particular household waste, characterized by a drum (14) which is rotatably mounted on a frame (12) and arranged transversely to the end of a conveyor, has a diameter of at least 1 m and carries projecting fingers (15). 2. Shredder according to claim 1, characterized in that all fingers (15) attached to its drum (14) have the same length. 3. Shredder: according to claim 1 or 2, characterized in that the fingers (15) of its drum (14) are arranged in rows on the generatrix of said drum (14). : 4. Shredder according to claim 3, characterized in that the fingers (15) of its drum (14) are spaced apart from one row to the other. --* - - ---·■
'"36' · - ■ ■ .■■-.. 5. Shredder according to claim 3 or 4, characterized in that the fingers (15) of one and the same row of its drum (14) are supported by a common rod (32) which is removably mounted on said drum (14). 30 6. Shredder according to claim 5, characterized in that the rod (32) carrying a row of fingers (15) is slidable in guides (33) firmly connected to the drum (14). ' " 1 7. Shredder according to one of claims 1 to 6, characterized in that the fingers (15) of the drum (14) are each inclined in the same direction with respect to the radius direction (R) of such a drum (14) passing through the root of the respective pinger, wherein they move away from this radius direction (R) upstream with respect to the direction of rotation of said drum (14). >. 8. Shredder according to one of claims 1 to 7, characterized 10 characterized in that each finger of the drum (14) has the shape j- a plate with an outline in the form of a parallelepiped : has. j 9. Shredder according to one of claims 1 to 8, characterized ■ 15 characterized in that athe conveyor, at the end of which the ( Drum. (14) is arranged, the floor of a vehicle (11) &idigr; whose chassis (13) has the associated frame (12) ; carries. f20 10. Shredder according to one of claims 1 to 9, characterized in that its drum il4) is protected by a >, cover is arranged. I 11. Shredder according to one of claims 1 to 1kJ, characterized '.. 25 characterized in that the average peripheral speed of the . tips of the fingers (15) of its drum (14) is limited to a maximum of 1800 m/min and preferably in the range of 750 to ■ 1100 m/miii. 30