FR2847507A1 - Recycling machine for bulk plastic materials has storage silo linked to compression stage, fusion chamber and shaping and cooling system - Google Patents

Abstract

The recycling machine consists of a storage silo (1) for bulk plastic materials, having an inclined lower wall (2) situated above a compression stage (3) in the form of an inclined rectangular parallelepiped chamber with at least one moving wall actuated by hydraulic or electric power cylinders (10). The compressed material is delivered to a conical melting chamber made from metal and heated by electrical resistances to a temperature of 200 - 280 deg C, and from it the plastic goes on to a shaping and cooling stage with a tunnel producing a plastic bar of predetermined size and made from a material such as aluminium that dissipates the heat from it.

Description

The present invention

  relates to a machine for recycling fusible plastic materials in bulk with a view to transforming them into a material of defined shape and of increased density, in particular for the purpose of

  transport and possibly reuse.

  This machine can be used for recycling for example

  polystyrenes and polyethylenes, without being limited to these materials.

  This recycling, as will be explained in more detail below, consists in this case in particular of melting the plastics. In

  With this in mind, the operating temperature will of course play a role in the selection of recyclable materials.

  Expanded polystyrene is a good example of the materials which are covered by the invention. Indeed, it is a material which is frequently used in particular for the wedging of articles in cardboard boxes / packing cases, and which is in this respect very present in number of companies, whatever their size. Waste often represents only a small weight which, however, corresponds to a relatively much larger volume, in particular for small and medium-sized enterprises, and its recycling cannot therefore be implemented in

  conditions as currently proposed, with only economically unfavorable results.

  Recycling is therefore currently organized as follows. There are possibilities of collecting expanded polystyrene, provided that it is clean and dry, so that it can be ground without cutting in order to reuse the beads thus individualized. Pickup is carried out using trucks, in which, due to the low density and considerable volume losses, the filling does not

hardly goes beyond 500 kg.

  Under these conditions, and given that the percentage of integration of the individualized beads is itself limited, it is understood that such recycling is hardly profitable.

  There are also machines which remelt the expanded expanded polystyrene 35, extrude and crush the material obtained, said machines being produced in the form of units capable of treating a ton of waste.

  per hour, which does not make sense in most cases, given the volumes to be processed, especially in small and medium-sized businesses.

  For most users potentially interested in recycling, it is indeed small quantities that are concerned, and the logic to be implemented must therefore be adapted. This should rather cover hypotheses of small volumes to be treated regularly than cases of large volumes. The present invention therefore aims to meet a need, that of making available to companies or individuals meeting the aforementioned profiles a tool allowing them to regularly recycle their waste in fusible plastic materials, in the hypothesis d 'a reasonably large quantity or for small volumes.

  To this end, the recycling machine of the invention, which therefore relates to fusible plastic materials in bulk, has the objective of transforming them into a material of defined shape and of increased density, and it is mainly characterized in that that it comprises a silo for storing these bulk materials, connected to a compression stage for said materials, the compression taking place in the direction of a melting chamber downstream of which is a forming and cooling stage.

  The main stages of recycling are therefore four in number, contributing to flexibility and efficiency of use.

  compatible with the above objectives.

  Firstly, the storage silo only allows the machine to be activated when a reasonable volume of plastic waste is reached. These are then treated by compression, essential to increase both the efficiency of the operation and the density of the resulting material. The merger therefore applies to compressed waste, again so as to avoid any drop in yield and efficiency, which could in particular result in pockets of gas inside the material obtained. The recycled finished product must have a maximum density.

  Finally, quite essentially, the molten material is in

  reconditioned, in the forming and cooling stage, in order to adapt it to possible operations occurring downstream of the machine, even if only transport.

  For this purpose, it may for example be advantageous to package the product obtained in easily palletizable boards, and therefore easily transportable. More specifically, the silo is arranged above the compression stage, so that the bulk materials fall therein by gravity, and it also has at least one opening in the lower part for the

  passage of said materials to the compression stage.

  According to a possible configuration, the compression stage is formed of a first volume receiving the bulk plastic materials from the silo, which undergo a first compression in the direction of a second volume in which a second compression takes place in the direction of the

melting chamber.

  In fact, this two-stage compression makes it possible to increase the efficiency of the process, so that the density obtained at the outlet is as high as possible. For example, when expanded polystyrene is used as an insulator, its density is of the order of 10 kg / m3. When used for wedging items in packaging boxes, its density is in the range of 13 to 15 kg / m3. The corresponding densities are therefore 0.01 and 0.013 to 0.015. It should also be mentioned that the real density of the cushioning materials, because of their often very specific geometry comprising many voids and

  recesses, is much lower than these values.

  The machine of the invention has by comparison made it possible to obtain densities of the order of 0.70 to 1 from waste in expanded polystyrene.

  Of course, it is quite possible to mix different types of plastics (polystyrene and / or polyethylene, PET), the whole forming a homogeneous material at the outlet of the melting chamber and the stage of

forming / cooling.

  Successive compressions are carried out, for each volume, by

  a wall movable in translation moving in piston inside these in the manner of a drawer by pushing in front of it the bulk materials, the wall movable in the first volume constituting besides, at the end of its displacement, a fixed wall of the second volume.

  In other words, given the particular configuration of the

  machine of the invention, the movable wall of the first volume closes the second volume after having filled it. This first volume, permanently open at the top so that the waste from the silo can be easily collected, therefore leads to the second volume.

  Preferably, said volumes are rectangular parallelepipeds, the first of which is arranged open under the opening of the silo, the movable walls forming pistons moving more perpendicularly to each other. In fact, bulk plastic materials then follow a path in which they take substantially three directions: a portion of vertical or close to vertical appearance in the silo, since it is gravity which directs the plastic waste which is disposed there. in bulk, a portion along the orientation of the parallelepiped constituting the first volume, the bottom of which is inclined, and a portion perpendicular to the latter and of horizontal appearance, in the second compression volume. The movable walls ensuring compression in said two volumes are each driven by at least one hydraulic or electric jack. In the first case, these jacks are controlled by a single hydraulic group, the operation of which can be programmed for example using a programmable controller, so that the compressions

  in particular are carried out sequentially.

  Position and / or pressure sensors are moreover arranged at the appropriate locations of the compression volumes or with respect to the paths of the movable parts of the jacks.

  To further improve the performance of the assembly according to the invention,

  the flow axis of the melting chamber is located in the extension of the axis of the second compression.

  The latter is preferably of conical appearance. For obvious reasons of thermal conductivity, this melting chamber is made of metal, and heated by means of resistors

  electrics integrated in the metallic mass.

  The temperature of the chamber can be controlled, in a determined interval, so that there can be adaptation to the materials to be melted. Thus, in use with expanded polystyrene, the operation of the machine is good at around 2100C. This same temperature is suitable for a certain number of polyethylenes, while PET, which is the material from which plastic bottles are made, for example, is not properly processed by the machine until around 2600C. In most cases, the melting chamber 30 will operate in a temperature range between 2000C and

2800C.

  At the outlet of the machine, the forming and cooling stage consists of a tunnel allowing the formation of a plastic bar of shape determined by the internal section of said tunnel, which is made in at

  minus a material capable of dissipating heat from the molten plastic.

  Preferably, this tunnel is in fact made of metal lined inside a coating facilitating the progression of the bar during cooling.

  According to one possibility, the metal chosen is aluminum, the good thermal conductivity of which is used for the evacuation of heat to the outside.

  As regards the internal coating, it is constituted by Teflon, in a thin layer, so as not to compromise the thermal evacuation function of the metal envelope. Preferably, the internal section of the

tunnel is rectangular.

  Advantageously, the forming and cooling tunnel and the downstream wall of the melting chamber are separated by at least one piece of thermal insulation provided with a window for the passage of the molten plastic.

  with an area substantially identical to that of the tunnel section.

  Given the respective functions of the melting chamber on the one hand, and of the tunnel on the other hand, this isolation interface is absolutely necessary in order not to compromise these functions. In fact, it is essential that the heat generated at the level of the melting chamber is transmitted inwards, in order to melt the plastic materials, and cannot escape towards the cooling stage constituted by the tunnel. In addition, this, if it had to remove the significant heat from the melting chamber, would be much less effective in cooling the finished product during formation.

  These insulation parts are preferably provided in known material

  under the name Teflon registered as a trademark.

  According to a particular configuration of the invention, the second compression volume and the melting chamber are separated by an anteroom whose walls are schematically arranged in an inverted cone widening towards the melting chamber, so as to prevent the return of the bulk materials to said second volume. This particular geometry also makes it possible to maintain the pressure on said materials upstream of the melting chamber even when the piston of the second compression volume is withdrawn.

  More specifically, at least two of the walls of the anteroom are oriented so as to constitute a flare in the direction of the chamber.

of fusion.

  According to one possibility, the storage silo can also be provided with a

grinding device.

  This can be designed for different types of products, to further facilitate the compression operations, and make it possible to achieve a result.

  even better, in terms of densification.

  So, for example, we realized that plastic bags, if they were not treated before being put in the silo, could lead to the establishment of bubbles inside the recycled finished product. , this

  which decreases on the one hand its density, and on the other hand is likely to obstruct its mechanical qualities with a view to future reuse.

  The use of a grinder or chopper avoids this drawback.

  Similarly, if it is clear that the first compression volume, during the displacement of the movable wall in the direction of the second compression volume, can crush at the end of the displacement of the expanded polystyrene in particular so as to keep only in the "drawer" a portion of the parts protruding from it, it has no effect on other plastic parts,

for example of the bottle type.

  We can therefore provide a crusher which reduces the volume of

bulk plastic materials.

  It should also be noted that such a crusher can directly supply the second compression volume, and that the machine can therefore make

  the economy of the first compression volume.

  The machine according to the invention, of relatively small dimension, makes it possible to treat at the option of the user all kinds of plastic waste materials. The invention will now be described in more detail, with reference to the appended figures, for which: - Figure 1 is a perspective view of the machine of the invention, showing the entrance to the storage silo; - Figure 2 is another schematic perspective view of the invention, seen from below; - Figure 3 is a side view, partially in section, of this machine; and - Figure 4 is a front view also partially in section, of

  said machine devoid of the storage silo.

  With reference to FIG. 1, the machine of the invention (M) comprises a silism (1) of prismatic appearance, of which an inclined wall (2) has a lower opening leading to the first compression volume (3), which is oriented parallel to this wall (2). The opening in the wall (2) actually corresponds to the largest area of said first compression volume (3). The latter takes the form of a parallelepiped 3 5 inclined rectangle, which opens into a duct also parallelepiped (4) in which is delimited on the one hand the second volume

  compression, and which further comprises a thrust cylinder located in the axis of said conduit.

  This cylinder (not visible in this figure), is located in the left part of the drawing, while the right part of the parallelepipedal duct (4) is resolved into a cylindrical portion (5) comprising on the one hand the anteroom separating the second volume compression of the melting chamber, and secondly said melting chamber.

  At the outlet of the latter, a tunnel (6) also parallelepiped frame allows the manufacture of high density plastic bars.

  The same elements appear in FIG. 2, which however show more clearly the lower fairing of the machine, as well as the slope of inclination of the first compression volume (3). Under the inclined wall

  (2), a fairing (7) made up of assembled sheets makes it possible to hide the location of the hydraulic unit.

  Feet (8) allow the machine to be positioned so that the upper opening of the silo (1) is substantially horizontal. These feet

  (8) can be fitted with rollers, making it easier to move the machine.

  Figure 3 shows, in side view, the relative arrangement of the two compression chambers. On the one hand, the compression chamber (3) 20 comprises a movable wall (9) actuated by a cylinder (10) moving

  parallel to the inclined wall (2).

  In the representation of Figure 3, the wall (9) is shown in the rest position, leaving the entire first compression volume (3) available. In this position, the bottom of said first compression volume (3) has the same surface as the opening made in the wall

silo (1) (see figure 1).

  Due to the slope, the materials which are compressed by the jack (10), by means of the movable wall (9) are naturally pushed towards the second compression volume (4) whose section appearing in this figure is a rectangle inclined in the extension of the first volume (3). When the movable wall (9) reaches the end of its travel, it serves as a side wall for the second volume (4).

  The cylinder (10) I mobile wall (9) association is used secondarily to make a rudimentary crushing for materials of expanded polystyrene type, in particular when said wall (9) comes close to the second volume (4), and shearing occurs of large expanded polystyrene pieces in contact with the bottom wall of the silo (1).

  A jack (11) actuates a wall of the second compression volume (4), a wall which matches the rectangular interior section of said volume, in the direction of the bottom of the figure. Bulk materials, already compressed by the

  wall (9) are then compressed towards the anteroom of the melting chamber and the latter, which are located in the cylindrical portion (5).

  This FIG. 3 also shows the hydraulic block (12) located inside the volume delimited by the fairing (7). This hydraulic group feeds via two pipes (not shown) each cylinder (10, 11), a programmable control device allowing, with the help of sensors, the

  automated control of the assembly.

  In this representation, the feet (8) have been provided with rollers (13)

  giving greater mobility to the machine (M).

  The representation of figure 4 does not include the silo (1) which is shown

  in the other three figures. This figure therefore illustrates quite clearly the operation of the first compression chamber, the movable wall (9) of which is integrated into a sort of drawer (T) driven by the jack (10).

  Likewise, a movable wall (14) is driven by the jack (11) in the second compression volume (4). This drive takes place in the direction of an anteroom (15) overlooking the melting chamber (16). The latter is made of metal, heated using electrical resistors,

  and has a conical internal recess (17).

  As mentioned above, the anteroom (15) has at least two walls flaring from the second volume (4), that is to say that the

  section increases in the direction of the melting chamber (16), resulting in a non-return effect and a pressure maintenance which improve the yield at the melting stage.

  The anteroom (15) and the melting chamber (16) are covered by a

  cylindrical cover (18), leaving a volume filled with insulating glass wool.

  At the exit of the melting chamber (16), the tunnel (19) is equipped with a

  internal coating (20) of material known by the name Teflon 30 registered as a trademark. This coating makes it possible to facilitate the forward movement of a bar (21) of plastic material being cooled, with a density of between 0.7 and 1.

  The interface between the melting chamber (16) and the tunnel (19) is produced by at least one part (22) of material known by the name 35 teflon registered as a trademark, which is intended to thermally insulate the tunnel (19) of said chamber (16). However, the interior window made in this part for the passage of the plasticized fluid must be of surface much larger than that of the orifice of the end of the melting chamber, so that with the restarting of the machine, the bar ( 21) being in the tunnel (19) can advance, and not be blocked solidified

  against said cooled part (22), which would happen if the central orifice thereof was the size of that of the downstream end of the cone of the melting chamber (16).

  The present invention has been described with reference to an example which is not

  by no means exhaustive of this invention. On the contrary, it encompasses variants of shapes and configurations which are within the reach of those skilled in the art.

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Claims (20)

  1. Machine for recycling fusible plastic materials in bulk with a view to transforming them into a material of defined shape and of increased density, characterized in that it comprises a silo for storing these bulk materials, connected to a compression stage of said materials, the compression taking place in the direction of a melting chamber downstream of   which is in the forming and cooling stage.   2. Plastic materials recycling machine according to the preceding claim, characterized in that the silo is arranged above the compression stage, in which the bulk materials   fall by gravity, and has at least one opening in the lower part for the passage of said materials towards the compression stage.   3. Machine for recycling plastic materials according to one of the   previous claims, characterized in that the compression stage consists of a first volume receiving the bulk plastic materials from the silo, which undergo a first compression in the direction of a second volume in which a second takes place   compression towards the melting chamber.   4. Machine for recycling plastic materials according to the preceding claim, characterized in that the compressions   successive are produced for each compression volume by a wall movable in translation moving inside these in the manner of a piston by pushing in front of them the bulk materials, the wall movable in the first: constituent volume at the end of probing a fixed wall of the second volume.   5. Plastic material recycling machine according to the preceding claim, characterized in that the volumes are   rectangular parallelepipeds, the first of which is placed open under the opening of the silo, the movable walls moving perpendicular to each other.   6. Plastic material recycling machine according to one of claims 4 and 5, characterized in that the movable walls are   each driven by at least one hydraulic or electric cylinder.   7. Plastic material recycling machine according to any one of claims 3 to 6, characterized in that the flow axis of the melting chamber is located in the extension of the axis of the second compression.   8. Machine for recycling plastic materials according to the preceding claim, characterized in that the melting chamber has a conical appearance, the large base of which opens on the side of the second compression volume, an axial orifice of smaller dimension allowing fluid flow in the forming and cooling stage.   9. Plastic material recycling machine according to any one of the preceding claims, characterized in that the melting chamber, made of metal, is heated by means of electrical resistors integrated in the metallic mass.   10. Plastic material recycling machine according to claim   previous, characterized in that the melting chamber is heated in a temperature range between 2000C and 2800C.   11. Plastic material recycling machine according to any one of the preceding claims, characterized in that the forming and cooling stage consists of a tunnel allowing the formation of a plastic bar of shape determined by the internal section of said tunnel, which is made of at least one material capable of removing heat from the molten plastic.   12. Machine for recycling plastic materials according to claim 20, characterized in that the tunnel is made of lined metal inside a coating facilitating the progression of the bar during cooling.   13. Plastic material recycling machine according to the preceding claim, characterized in that said coating consists of   material known as teflon registered as a trademark.   14. Plastic material recycling machine according to one of claims 12 and 13, characterized in that the tunnel is made of aluminum.   15. Plastic material recycling machine according to one of claims 11 to 14, characterized in that the forming and cooling tunnel and the downstream wall of the melting chamber are separated by at least one piece of thermal insulation provided with a window for the passage of molten plastic with a surface substantially identical to that of the section of the tunnel.   16. Machine for recycling plastic materials according to the preceding claim, characterized in that the insulation piece or pieces are en'teflon "   17. Plastic materials recycling machine according to any one of claims 3 to 16, characterized in that the second 1 2   compression volume and the melting chamber are separated by an anteroom whose walls are schematically arranged in an inverted cone in the direction of the melting chamber.   18. Plastic materials recycling machine according to the preceding claim, characterized in that at least two of the walls of the anteroom are oriented so as to constitute a flare in the direction of the melting chamber.   19. Machine for recycling plastic materials according to any one of the preceding claims, characterized in that the silo   storage is equipped with a chopping / grinding device.   20. Machine for recycling plastic materials according to any one of claims 11 to 19, characterized in that the forming and cooling tunnel has a rectangular section.