Abstract:
In a method and apparatus for unloading fragile products from a storage container, comprising a step of transferring the products by gravity from a container to an unloading station below along a given, straight unloading path, a product interception device, with a given linear movement along the unloading path, intercepts the products and accompanies them at a first given speed to the unloading station, until a continuous column of products is formed, substantially extending between the container and the unloading station; then, during product unloading, the column is gradually shortened by raising the unloading station at a second given speed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a method and apparatus for unloading fragile products.  
           [0002]    The present invention is particularly advantageous when applied in industries in the pharmaceuticals sector, or more generally in the chemical sector, in which particularly delicate products such as tablets, capsules or similar products must be unloaded from a storage hopper container.  
           [0003]    The description below refers, without limiting the scope of application, to equipment for the pharmaceutical sector, in which the above-mentioned products arrive from tableting machines, capsule filling machines or coaters.  
           [0004]    In the known type of apparatus, the above-mentioned storage hopper container is emptied through a lower outfeed opening, from which the products in the container are transferred to an unloading station connected to a lower collection tank which, in turn, may be connected, for example, to a packaging machine for such products.  
           [0005]    In such apparatus, the unloading station is normally located below the above-mentioned lower outfeed opening, to which it is connected by a rigid cylindrical pipe positioned vertically under the container. In this way, the container is emptied by gravity, with evident advantages in terms of system simplicity and costs.  
           [0006]    However, in an apparatus of the type described above, the products may suffer more or less serious damage when free falling under gravity from the container to the collection tank.  
           [0007]    A first cause of this disadvantage derives from the need to allow complete filling of the collection tank, meaning that the unloading station, consisting of a lower outfeed opening in the above-mentioned cylindrical pipe, must be separated from the base of the collection tank by a distance which is at least equal to the height of the tank.  
           [0008]    A second cause is the fact that the above-mentioned cylindrical pipe is normally quite long (around two or three meters), since the container and the collection tank are usually located on two adjacent storeys in an industrial building.  
           [0009]    The information above makes it evident that the drop to which the products are subjected as they free fall under gravity from the upper container to the lower tank, is normally quite considerable and, in some cases, for fragile products, may give rise to a speed and impact energy against the base of the tank such that the products are seriously damaged.  
           [0010]    In particular, in the case of capsules, impact of the latter against the base of the collection tank may ruin the capsules.  
           [0011]    In contrast, tablets may be chipped, resulting not only in the above-mentioned tank contamination risks, but also an unwanted reduction in the medicinal dose in the tablets, with obvious consequences in terms of therapeutic effectiveness.  
           [0012]    Obviously, such disadvantages may also affect coated products.  
         SUMMARY OF THE INVENTION  
         [0013]    The aim of the present invention is to overcome the above-mentioned disadvantage.  
           [0014]    Accordingly, the present invention provides a method for unloading fragile products by transferring the products along a given unloading path, from a storage container to an unloading station located below the storage container, the method comprising at least an initial transfer step during which the products are intercepted along the path and accompanied with a given law of motion and at a given first speed to the unloading station, until a continuous column of products is formed, substantially extending between the storage container and the unloading station.  
           [0015]    The present invention also relates to an apparatus for unloading fragile products.  
           [0016]    Accordingly, the present invention provides an apparatus for unloading fragile products, being equipped with a storage container which holds the products, a station for unloading said products which is located below the container, and conveyor means which feed the products from the container to the unloading station along a given unloading path, wherein the conveyor means comprise means for intercepting the products and means which drive the intercepting means, imparting to the intercepting means at least a first movement along the unloading path away from the storage container, said first movement being performed in accordance with a given first law of motion and at a given first speed.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    The invention is now described with reference to the accompanying drawings, which illustrate a preferred embodiment without limiting the scope of application, and in which:  
         [0018]    [0018]FIG. 1 is a schematic view with some parts cut away for greater clarity and in a first given operating instant, of an embodiment of the apparatus in accordance with the present invention;  
         [0019]    [0019]FIG. 2 illustrates the apparatus shown in FIG. 1, in a second given operating instant;  
         [0020]    [0020]FIG. 3 illustrates the apparatus shown in FIG. 1, in a third given operating instant;  
         [0021]    [0021]FIG. 4 illustrates a detail from FIG. 3, with some parts in cross-section and other parts cut away for greater clarity;  
         [0022]    [0022]FIG. 5 is plan view of a detail from FIG. 4;  
         [0023]    [0023]FIG. 6 illustrates the apparatus shown in FIG. 1, in a fourth given operating instant.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    With reference to FIG. 1, the numeral  1  denotes as a whole an apparatus for unloading fragile pharmaceutical products  47  (illustrated only in FIGS. 4 and 6), such as tablets, capsules or similar products, from an upper storage container  2  in the form of a hopper, to a lower collection tank  3 . The storage container  2  and tank  3  are normally housed on two adjacent storeys  4  and  5 , one upper and one lower, of an industrial building (not illustrated).  
         [0025]    The tank  3  is supported by a moving platform  6  of a lifting device  7  of the known type, with which the tank  3  may be positioned at a height from the floor of storey  5  which varies between a lower level (not illustrated) substantially coinciding with that of the floor of storey  5 , in which the tank  3  can be connected, for example, to a packaging machine (not illustrated), and an upper level, in which an upper loading opening  8  in the tank  3  is located close to a through-hole  9  between the ceiling of storey  5  and the floor of storey  4 .  
         [0026]    A throttle valve of the known type, which is not illustrated, may be used to connect the opening  8  to a short feed pipe  10  inserted in the hole  9  and protruding on storey  4 , with a loading opening  11  substantially level with the floor of storey  4 . As illustrated in FIG. 1, the container  2  is supported at a given height H′ from the floor of storey  4  by a mobile load-bearing structure  12  on wheels  13 , comprising a supporting device  48  equipped with a mechanical lifter  49  operated by a lead screw and nut mechanism and connected to the storage container  2  by a frame  50  with a pin  51  which has a horizontal axis  52  about which the tank  2  and the frame  50  can turn in order to move the frame  50  and the tank  2  from the vertical position illustrated in FIG. 1 to a horizontal position which is not illustrated.  
         [0027]    In practice, the tank  2  is positioned with a lower outfeed opening  14  aligned with the loading opening  11  of the pipe  10  and is brought to a given height H by the lifter  49 , as illustrated in FIGS. 2, 3,  4  and  6 .  
         [0028]    As is more clearly illustrated in FIG. 4, on opposite sides of the opening  14 , the container  2  has a loading opening  15  connected to an outfeed pipe  16  of a tank or of a feed unit (not illustrated) for the above-mentioned products  47 .  
         [0029]    The opening  14  is connected to a transfer unit  17  which transfers the products  47  by gravity from the container  2  to the tank  3  along a given unloading path P which is straight and substantially vertical.  
         [0030]    The unit  17  comprises a flexible changeable tubular bag  18 , made of polyethylene and being able to extend longitudinally along the path P from a gathered position (FIG. 1) to an extended position (FIG. 3). In particular, the bag  18  is of the disposable type.  
         [0031]    The bag  18  has an upper end  19  which is connected in a removable fashion to the container  2 , at the opening  14 , by means of an O-ring  20  of the known type, and an opposite, lower end  21 , which is connected in a removable fashion to a device  22  which intercepts the above-mentioned products, by means of another O-ring  23 , identical to the O-ring  20 .  
         [0032]    The intercepting device  22  is part of the transfer unit  17  and comprises a valve element  24  which, in turn, comprises a cylindrical steel tubular body  25  constituting a relatively short pipe  26  for transferring the products along the path P. In particular, the O-ring  23  connects the lower end  21  of the bag  18  to an upper end  27  of the body  25 , so that the pipe  26  formed by the latter is an extension of the pipe  28  formed by the bag  18 .  
         [0033]    The valve element  24  also comprises a main shutter  29  and a safety shutter  30 , the former located above the latter along the path P inside the body  25  and each shutter having a valve element  24  opening configuration and a valve element closing configuration. More specifically, the shutters  29  and  30  each consist of an inflatable silicone balloon, the openings  31 ,  32  being connected, by means of a through-hole  33 ,  34  made in the cylindrical side wall of the body  25 , to actuator parts (not illustrated) which allow it to pass between the deflated opening configuration, in which the balloon leaves the passage consisting of the pipe  26  free, and an inflated closing configuration, in which the balloon blocks the passage.  
         [0034]    The bottom of the body  25  is delimited by an opening  35  forming an unloading station S for the products transferred along the path P, and is mobile in a linear fashion along the path P to vary the height of the station S relative to a lower wall  36  of the tank  3  (FIGS.  1 - 3 ).  
         [0035]    For this reason, as FIGS. 4 and 5 more clearly show, the upper base of the end  27  of the body  25  has a plurality of welded motor-driven rods  37  (four in the embodiment illustrated), which extend parallel with the path P, inside the bag  18  and the container  2 , exiting a top wall  38  of the container at the through-holes  39  and, on opposite sides of the body  25 , connecting to a ring  40  which is, in turn, connected to an output slider  41  of a linear actuator  42  of the known type.  
         [0036]    The length of the rods  37  is such that the actuator  42  can impart to the body  25  a linear downstroke movement towards a lower end position (FIG. 3), in which the unloading station S is positioned a relatively short distance from the lower wall  36  of the tank  3  when the latter is at its above-mentioned upper level, and a linear upstroke towards an upper end position (FIG. 1), in which the body  25  disengages from the pipe  10 , allowing maintenance work to be carried out on the transfer unit  17 .  
         [0037]    The rods  37  also act as retaining elements, designed to hold the bag  18  in a substantially cylindrical tubular configuration when the bag  18  is gathered or extended as it passes between the above-mentioned gathered and extended positions.  
         [0038]    The ring  40  and the actuator  42  are housed in a box-shaped body  43 , the base of which is supported by the upper wall  38  of the container  2  and which, together with the rods  37 , is part of the transfer unit  17 .  
         [0039]    Finally, the apparatus comprises a control unit  44  for the actuator  42  (FIGS.  1 - 3 ). The control unit  44  is supported by the structure  12  and is connected, at infeed, to a sensor  45  located inside a through-hole  46  made in the upper wall  38  of the storage container  2 . The sensor  45  detects the quantity of products  47  stored in the storage container  2  and sends a signal to the control unit  44  which, by means of the actuator  42 , commands the downstroke and subsequent upstroke of the body  25  along the unloading path P in accordance with the methods indicated in the description of how the apparatus  1  operates.  
         [0040]    The control unit  44  also controls the above-mentioned actuator elements (not illustrated) connected to the openings  31  and  32  of the balloons which form the shutters  29  and  30 .  
         [0041]    Apparatus  1  operation is now described starting with the condition in which the body  25  is at the loading opening  11  of the pipe  10  and in its above-mentioned upper end position, the bag  18  is in the above-mentioned gathered position and completely full of products to be unloaded, and the balloons which form the shutters  29  and  30  are in their closing configuration, blocking the pipe  26  formed by the body  25 .  
         [0042]    At this point, the control unit  44  issues a command to the actuator  42  to impart to the body  25  and, therefore, to the shutters  29  and  30 , a downstroke towards the above-mentioned lower end position. The downstroke is performed with a given first law of motion and at a given first speed.  
         [0043]    The downstroke speed and law of motion are determined according to the data supplied by the sensor  45 , so that a continuous column of products forms above the shutters  29  and  30 . In particular, the first law of motion may be a continuous or an inching movement. In both cases, the function of the sensor  45  is to keep the quantity of products  47  inside the storage container  2  substantially constant.  
         [0044]    When the body  25  reaches its lower end position, the column of products substantially extends between the storage container  2  and the unloading station S which is at its lowest level, consisting of the lower opening  35  of the body  25 .  
         [0045]    The control unit  44  then issues the command for deflation of the above-mentioned balloons, thus starting the unloading operation, during which the products are transferred by gravity along the pipes  28  and  26  formed by the bag  18  and the body  25 , as illustrated in FIG. 6.  
         [0046]    It should be noticed that since, as already indicated, the pipe  26  is relatively short, the distance between the balloons which form the shutters  29  and  30  and the unloading station S is negligible relative to the length of the overall unloading path P. In other words, when the balloons  29  and  30  are deflated, the products reach the lower wall  36  of the container  2  with a relatively contained impact speed, substantially determined by the distance between the unloading station S and the wall  36 .  
         [0047]    It must also be specified that, in order to reduce the above-mentioned impact speed to a minimum, the control unit  44  commands, in succession, first the deflation of the upper balloon  29 , and then the deflation of the lower balloon  30 .  
         [0048]    During product unloading, depending on the data supplied by the sensor  45 , the control unit  44  commands the return upstroke of the body  25 , then of the unloading station S, with a given second law of motion and at a given second speed until the tank  3  is completely full.  
         [0049]    As specified for the first law of motion, the second law of motion and feed speed may also be continuous or inching.  
         [0050]    In an embodiment invention, which is not illustrated, of the apparatus according to the present invention, the lifting device  7  illustrated in FIGS.  1  to  3  may be absent. In such cases, the rods  37  are, obviously, longer than in the embodiment described above. Again, the length of the rods  37  is such that they allow the actuator  42  to impart to the body  25  a linear downstroke movement towards a lower end position, in which the unloading station S is a relatively short distance from the lower wall  36  of the tank  3 , and a linear upstroke movement towards an upper end position, in which the body  25  disengages from the pipe  10 , allowing maintenance work to be carried out on the transfer unit  17 . In another embodiment which is not illustrated, the load-bearing structure  12  and the collection tank  3  may be mounted on the same storey  4  but, obviously, the storage container  2  is higher than the collection tank  3  and apparatus  1  operation does not differ from that described above.