Abstract:
The invention relates to a novel device ( 10 ) for separating composite materials, comprising a cylindrical rotor ( 17 ), which has a shaft driven by a motor and strip-shaped first impacting tools ( 30 ), which are evenly distributed over the circumference and which protrude from the rotor parallel to the shaft, and comprising a cylindrical stator ( 12 ) that surrounds the rotor, wherein an annular space ( 32 ) is formed between the rotor and the stator. An air supply channel ( 15 ) opens into the upper region of the annular space ( 32 ) and an air removal channel ( 38 ) leads away from the lower region of the annular space. Furthermore, the cylindrical wall of the stator ( 12 ) has strip-shaped second impacting tools ( 31 ), which are evenly distributed over the circumference and which protrude radially inward.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the US national phase entry of International Patent Application no. PCT/IB2011/055408, filed Dec. 1, 2011, which claims priority to Swiss patent application no. 2027/10, filed Dec. 1, 2010. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a device for separating composite materials having a cylindrical rotor, which has an axis of rotation driven by a motor, and strip-shaped first impact tools, which are distributed regularly around the circumference and protrude parallel to the axis of rotation from the rotor, and having a cylindrical stator enclosing the rotor, wherein a ring space is formed between rotor and stator, and having an air feed channel opening into the ring space and an air exhaust channel leading away from the ring space. 
       BACKGROUND 
       [0003]    Composite materials and the mixtures thereof are very frequently used as packaging or as a structural element in construction and in mechanical engineering, for example. The physical properties of various materials are combined, in order to fulfill the desired mechanical functions. A further reason for the increasing use of composite materials is that they can be produced with lower material and energy outlay and therefore resources can be saved. 
         [0004]    Various examples of such composite materials will now be described on the basis of following  FIGS. 1 to 3 . 
         [0005]      FIG. 1  shows a composite material  1  made of a thin aluminum layer  2  of 20 to 40 μm in a sandwich with two layers  3  made of LDPE (low-density polyethylene) of 120 μm, which is used as a laminate for tubes. The aluminum is used as a barrier layer against light and prevents the diffusion of liquids and gases. 
         [0006]      FIG. 2  shows the pattern of a printed circuit board  4  for electronic circuits, which consists of a composite of thin copper layers of 5 to 20 μm and glass-fiber-epoxy layers of 6 to 50 μm and more. 
         [0007]      FIG. 3  shows a detail of an aluminum composite plate  7 , which consists of two aluminum layers  8  of 200 to 500 μm and an interposed layer  9  made of HDPE (high-density polyethylene) of approximately 2 to 4 mm. Other plastics may also be used for this purpose. Such sandwich plates are used in facade construction or in vehicle construction. 
         [0008]    Such composite materials cause great problems in the case of disposal, since precise separation of the individual materials is hardly possible. In rare cases, the composite materials are processed by means of thermal or wet-chemistry processes. These processes are typically not very efficient and substantially stress the environment. In addition, the recycled materials are frequently produced in inadequate quality. Another possibility is to crush the composite materials and mechanically separate the materials. 
         [0009]    For example, a device for treating composite elements is known from WO-A-2006/117065, in which the composite material has been crushed to a grain size of 5 to 50 mm and the crushed particles are conducted in a feed channel to a breaking-up device. The device consists of a rotating rotor, having tools implemented as strips, which is arranged in a cylindrical stator. An air stream is conducted in the opposite direction in the ring space between rotor and stator from bottom to top, in order to discharge dust via a dust removal pipe attached on top. As the particles are broken up, they are crushed further when they impact on the strip-shaped tools, as described in greater detail in conjunction with  FIG. 13 . The air stream is necessary, on the one hand, to keep the particles for a sufficiently long time in the ring space and, on the other hand, to discharge the dust arising in this case upward. 
         [0010]    Due to the air stream from bottom to top, the digested particles remain longer in the ring space than is necessary for the separation. Lighter and heavier particles thus also have a dwell time of approximately equal length in this ring space. Furthermore, the danger exists that the lighter particles will be drawn upward with the air stream, which results in further complications. 
       SUMMARY 
       [0011]    The present invention is based on the object of specifying a device for separating composite materials, which separates the components with greater precision from one another, so that no dust arises. 
         [0012]    This object is achieved by a device for separating composite materials having a cylindrical rotor, which has an axis of rotation driven by a motor, and strip-shaped first impact tools, which are distributed regularly around the circumference and protrude parallel to the axis of rotation from the rotor, and having a cylindrical stator enclosing the rotor, wherein a ring space is formed between rotor and stator, and having an air feed channel opening into the ring space and an air exhaust channel leading away from the ring space, characterized in that the air feed channel opens into the top region of the ring space and the air exhaust channel leads away from the bottom region of the ring space, and the cylindrical wall of the stator has strip-shaped second impact tools, which are distributed regularly around the circumference and protrude radially inward. 
         [0013]    The device according to the invention has the great advantage that the particles to be treated are not crushed further or even pulverized during the separation method and therefore dust removal is completely dispensed with. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    Further advantages of the invention result from the dependent patent claims and from the following description, in which the invention is explained in greater detail on the basis of an exemplary embodiment shown in the schematic figures. In the figures: 
           [0015]      FIG. 1  shows a composite material  1  made of a thin aluminum layer  2  of 20 to 40 μm in a sandwich with two layers  3  made of LDPE (low-density polyethylene) of 120 μm, which is used as a laminate for tubes, 
           [0016]      FIG. 2  shows the pattern of a printed circuit board  4  for electronic circuits, which consists of a composite of thin copper layers of 5 to 20 μm and glass-fiber-epoxy layers of 6 to 50 μm and more, 
           [0017]      FIG. 3  shows a detail of an aluminum composite plate  7 , which consists of two aluminum layers  8  of 200 to 500 μm and an interposed layer  9  made of HDPE (high-density polyethylene) of approximately 2 to 4 mm, 
           [0018]      FIG. 4  shows a perspective view of a device for separating composite materials, 
           [0019]      FIG. 5  shows a top view of the device, 
           [0020]      FIG. 6  shows a cross-section in the longitudinal direction through the device, 
           [0021]      FIG. 7  shows an outline of the device, 
           [0022]      FIG. 8  shows a schematic view of a composite material and the Shockwaves generated therein, 
           [0023]      FIG. 9  shows a schematic top view of a part of the rotor and a part of the stator, 
           [0024]      FIG. 10  shows a schematic view of the device to illustrate its function, 
           [0025]      FIG. 11  shows the rotor and the stator in a perspective view, 
           [0026]      FIG. 12  shows the rotor in an exploded view, 
           [0027]      FIG. 13  shows a detail view from  FIG. 12 , and 
           [0028]      FIG. 14  shows a flow chart of the method for separation. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIGS. 4 to 7  show a device  10  for separating composite materials, which has a machine frame  11 , which carries a cylindrical stator  12  and has a receptacle  13  for a drive motor (not shown). Two air inlet openings  15  and a material feed opening  16  are provided on top on the lid  14  of the device  10 . As is obvious from  FIG. 6 , a rotor  17  is arranged so it is rotatable on a shaft  18  in the stator  12 . The shaft  18  has a support ring  19  at approximately two-thirds height, on which the rotor  17  is supported. The rotor  17  is fastened using a press fit on the shaft  18 . Furthermore, two bearings  21  and  22  are provided in a bush  23  on the machine frame  11 , in which the shaft  18  is mounted so it is rotatable. The shaft  18  has on its bottom end  25  a drive cylinder  26  having external grooves  27 , in order to be driven by means of a toothed belt (not shown) by the motor. 
         [0030]      FIG. 8  shows a part of the rotor  17  and a part of the stator  12 . The rotor  17  has first tools  30  arranged regularly on its circumference, which are implemented as strips and have a height of approximately 10 to 15 mm. The stator  12  also has strip-shaped second tools  31 , which have a height of approximately 5 to 8 mm, arranged regularly on its circumference. The second tools  31  are distributed in a ratio 2:1 on the interior of the circumference of the stator  12 . A ring space  32 , in which the particles of the composite materials to be broken up are located, is formed between the stator  12  and the rotor  17 . The flight path  33  of a particle of a composite material to be broken up is shown by dashed lines. The rotor  17  rotates counterclockwise to the stator  12 . 
         [0031]    The stator  12 , the rotor  17 , and the helical flight path  33  in the ring space  33  are shown solely schematically in  FIG. 9 . The arrow  35  indicates the material feed of the composite materials to be broken up through the material feed opening  16  and the arrows  36  indicate the air feed through the air inlet openings  15  (see  FIGS. 4 to 7 ). Due to the feed of the composite materials from the top into the device  10 , the particles describe a helical path  33  from top to bottom. The velocity and the pitch can be regulated by the speed of the rotor  17  and by the air feed. After the broken-up material exits, it is conveyed further by an air stream  37  into a channel  38 . The material, which is broken up into fractions, is separated therein in a known manner by means of screens, liquid bed separators, sifters, and corona separators into the individual components. 
         [0032]    In practice, the rotor  17  is driven at a rotational velocity of 800 RPM, for example. The first strip-shaped tools  30  are thus guided past the second strip-shaped tools  31  at a very high velocity and very large forces arise on the entrained particles at the moment of passage. Due to these forces, the particles are briefly very strongly accelerated and subsequently—when the first tools  30  are located between the second tools  31 —decelerated again by the rapid drop of the forces. This procedure repeats at a high frequency, which is determined by the distance between the first tools  30 , the distance between the second tools  31 , and the rotational velocity of the rotor  17 . The forces act differently on the layers of the composite material, so that shearing occurs along the boundary between the various materials. So-called Shockwaves or transverse waves can be observed in the composite material. Since the energy is damped differently because of the different material properties such as density, elasticity, and stiffness, the materials are separated by shear forces. Plastics have a rather absorbent and vibration-damping effect and metals have more of a vibration-transmitting effect. In  FIG. 10 , these Shockwaves  41  are shown in a part  40  of a composite material, which consists of a PE layer  42  and an aluminum layer  43 . The thrust forces on the layers  42  and  43  are indicated with the arrows  45 . 
         [0033]    The design of the device according to the invention having the air stream from bottom to top has the effect that the dwell time of the heavier particles in the ring space  33  is substantially shorter than the dwell time of the lighter particles. For example, the heavier particles, which originate from aluminum parts or copper cables, circle approximately 100 times in a spiral shape in the ring space  33 , while lighter particles, which originate from circuit boards or the like, circle approximately 200 times in a spiral shape in the ring space  33 . The various components of so-called electrical waste can thus be separated substantially better. 
         [0034]    To prepare the composite materials to be separated, they are crushed before being introduced into the device  10 . The material is typically crushed to a size of 5 to 50 mm. This size is dependent on the respective composite material. If the layers are relatively thin, as in the case of a tube laminate (&lt;20 μm) and the adhesion forces are large, the composite material is crushed in the device  10  to a size of 5 to 8 mm. In the case of composite materials having a relatively thick layer (&gt;200 μm) such as aluminum, and low adhesion forces, crushing is performed to 40 to 50 mm. The feed into the device  10  is performed continuously and can be metered. 
         [0035]    The rotor  17  has a diameter of 1200 to 2400 mm, 2000 mm in the standard version. The internal diameter of the stator  12  is between 1250 and 2450 mm, the standard is 2050 mm. The structural height of the rotor  17  is between 375 and 625 mm, 500 mm is standard. The first and second tools  30  and  31  are typically arranged in 3 to 5 levels respectively vertically one over another, 4 levels are provided in the standard. The total number of the first tools  30  of the rotor  17  is between 50 and 150, 96 is standard. The distance between the first tools  30  of the rotor  17  and the second tools  31  of the stator is settable between 0.5 and 25 mm. 
         [0036]      FIG. 11  is a perspective view of the stator  12  and the rotor  17  having the strip-shaped first tools  30  and the strip-shaped second tools  31 . As is apparent therefrom, the strip-shaped second tools  31  are formed as wall sections held by the stator ring  12 , which have a sawtooth pattern having serrated projections  51  on the inner side. In this case, there is a ratio of 1:8 between first tools  30  and projections  51  around the circumference of the rotor  17 . No shaft is provided in this case, but rather a bush  52  is provided, which is fastened by spokes  53  on an outer cylinder  54 . The ratio between the first and second tools  30  and  31  is preferably between 1:2 and 1:8. 
         [0037]      FIG. 12  shows the rotor  17  in an exploded view, wherein a detail view is shown in  FIG. 13 . Wall elements  55  are screwed onto the outer cylinder  54 , with guide rails  56  clamped in between. The guide rail  56  has a dovetail groove  57  having protruding edges  58 , which fit into a groove  59  of the wall element  55 . Four first tools  30  are now pushed into the guide rail  56 , which have a similar dovetail profile  60  on one longitudinal edge  58 . A top flange  62  is screwed on top onto the external cylinder  54  and a bottom flange  63  is screwed onto the bottom, so that the first tools  30  are fixed in the axial direction. Furthermore, the rotor  17  is protected by the top lid  14  and by a bottom cover  65  against the penetration of separated materials. First tools  30  having a greater width can be provided to reduce the distance between first tools  30  and second tools  31  if needed. The replacement of first tools  31  can be performed particularly easily due to the formation of the guide rails  56 . 
         [0038]    The precise sequence during the separation of composite materials such as electronic circuits is shown in greater detail in  FIG. 14  in a flow chart. The composite materials, which are indicated with the arrow  71  and are to be separated, are first freed of interfering materials  73  and first iron parts  74  using scissors or a coarse separator  72 . Preliminary crushing  75  is then performed, during which first plastics  76  and second iron parts  77  are removed. Subsequently, there is a further crushing  78 , whereby second plastics  79  and third iron parts  80  are removed. In a fractionator  81 , which the device  10  forms here, and a Corona separator and optionally a screen  82 , residual materials  83 , noble metals and copper  84 , and mineral materials  85  are now removed. In a second screen  86  and a first fluidized bed separator  87 , further residual materials  88  are then removed. Finally, aluminum  90  and copper  91  are obtained by a second fluidized bed separator  89 .