Abstract:
The invention provides an apparatus for metering pulverulent filling material, comprising at least one metering wheel with a plurality of metering chambers for accommodating filling material, wherein a plurality of metering chambers are formed by means of a common component, and the common component can be displaced in the radial direction of the metering wheel using an adjusting means in order to change the volume of the metering chambers.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for metering pulverulent filling material. An apparatus of the relevant type is already known from DE 10 2007 018 036 A1. This comprises a filling wheel with at least one metering chamber for accommodating filling material, wherein the metering chamber is arranged in a sleeve element. An adjusting device is provided for adjusting a position of the sleeve element in the radial direction of the filling wheel. The sleeve element is arranged in an opening in a housing. 
     It is the underlying object of the invention to indicate an apparatus for metering pulverulent filling material which allows simple adjustment of the metering volume with a multiplicity of metering chambers in a particularly simple manner. 
     SUMMARY OF THE INVENTION 
     Given the above, the apparatus according to the invention for metering pulverulent filling material has the advantage that it can be adjusted in a particularly simple manner by virtue of the integration of a plurality of metering chambers in a common component, preferably a format-specific bar. It is thereby possible to reduce the number of individual parts in the metering apparatus. In particular, it is possible to have recourse to just a small number of format-specific components that are expensive to produce, thanks to what is now a simple way of adjusting the metering volume of a plurality of integrated metering chambers. Moreover, the apparatus can be assembled and moved jointly in a compact manner as a unit. 
     In an expedient development, provision is made for the common component to have at least one recess to accommodate a supporting means. It is now a particularly simple matter to introduce a filter between the underside of the metering chambers and the supporting means. This filter can preferably extend across a plurality of metering openings, thus enabling just a single filter to be used for a plurality of metering chambers. Exchanging the filter is thereby also made easier. 
     In an expedient development, provision is made for the supporting means to have a common air duct, which is connected to a plurality of metering chambers. It is thereby possible to further simplify the component and to ensure more reliable filling and emptying of the metering chambers through the appropriate application of a vacuum or compressed air. 
     In an expedient development, provision is made for a plurality of common components to be provided, each having a multiplicity of metering chambers with the corresponding sleeve projections. These common components can be adjusted equally by means of a single adjusting means to change the metering volume. A cam is preferably used as an adjusting means. 
     In an expedient development, provision is made for spring means to exert on the common component a force opposite to the direction of movement of the adjusting means. This ensures that the common component can also be adjusted back in the direction opposite to the direction of movement. 
     In an expedient development, provision is made for the air duct to be connected to a coupling part. This ensures that the common component with the air duct contained therein can also be adjusted, at least in the radial direction. 
     Further expedient developments will become apparent from further dependent claims and from the description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An illustrative embodiment of the apparatus according to the invention for metering pulverulent filling material is illustrated in the drawing and described in greater detail below. 
         FIG. 1  shows a perspective view as a cross section through the metering wheel, and 
         FIG. 2  shows a longitudinal section through the metering wheel in perspective view. 
     
    
    
     DETAILED DESCRIPTION 
     An apparatus  8  for metering comprises a metering wheel  11 . This metering wheel  11  consists of guide means  14 , which form a fixed part of the metering wheel  11  and have guide surfaces  15 , over which the common components  16  can be moved in the radial direction. For this purpose, adjusting means  10  are provided, said adjusting means having a cam-shaped contour. By rotating the adjusting means  10 , the four common components  16  can be adjusted in the same way in the radial direction. By way of example, the metering wheel  11  has four common components  16 , which are each arranged offset by 90° on the circumference of the metering wheel  11 . The common component  16  is of substantially rectangular design. In the interior, it has a cavity  19 . The cavity  19  serves to accommodate a supporting means  20 . On the outward-oriented upper side, the common component  16  has a plurality of sleeve projections  18  arranged adjacent to one another in the axial direction. As an extension of the openings in the sleeve projections  18 , the supporting means  20  has corresponding openings  21 . The supporting means  20  has a substantially rectangular cross section, with the outward-directed upper side being reduced in length relative to the base by means of chamfers. The side faces are of parallel design and are oriented substantially in the radial direction, said side faces thus enabling the supporting means  20  to be moved relative to the common component  16 . The interior of the supporting means  20  is likewise hollow, giving rise to an air duct  28 . This air duct  28  connects all the openings  21  of the supporting means  20 . The upper side of the supporting means  20  serves as a countersurface for a filter  12 , which is arranged between the sleeve projections  18  and the openings  21 . The supporting means  20  can be moved easily in the radial direction within the cavity  19 , thus enabling the filter  12  to be clamped and also enabling the clamping to be canceled in order to replace the filter  12 . To clamp the filter  12 , appropriate clamping means  22 , such as screws, particularly preferably grub screws, are provided, said screws pressing the supporting means  20  radially outward against the filter  12  and the common component  16 . Secured on the outside of the guide means  14  are spring means  30 , which, at the outer circumference, engage in a shoulder  17  of the common component  16 . This shoulder  17  is, for example, formed by a corresponding recess on the radially outer side of the common component  16 . The spring means  30  exerts a force directed toward the center of the metering wheel  11  on the common component  16 , with the result that, when the lift of the adjusting means  10  is reduced, the common component  16  is moved in the direction of the center of the metering wheel  11 . As an alternative, it would also be possible to provide a spring means  30 ′ which was arranged in the radial direction and was supported relative to the guide means  14  on a shoulder of the common component  16  which is arranged closer to the center in order to apply the appropriate force in the direction of the center. 
     According to  FIG. 2 , the metering wheel  11  is then shown with a metering drum sleeve  24  which forms the outer surface or circumferential surface of the metering wheel  11 . As a radial extension of the sleeve projections  18 , respective corresponding openings are provided in the metering drum sleeve  24 . The inside diameter of said openings in the metering drum sleeve  24  is matched to the outside diameter of the sleeve projections  18 , thus enabling the sleeve projections  18  to be moved into the openings in the metering drum sleeve  24  when the common component  16  is moved radially outward. A metering chamber  13  for filling with filling material is now formed by the volume bounded by the openings in the metering drum sleeve  24 , the internal openings in the sleeve projections  18 , as far as the filter  12 . The metering volume of the metering chambers  13  can be changed by means of a radial adjustment of the sleeve projections  18 . The metering drum sleeve  24  is held by the outer surfaces of the guide means  14  and by laterally arranged bearing covers  32 . The common components  16  are designed to be adjustable relative to the metering drum sleeve  24 . In the bearing cover  32 , there is also an opening for the air connection of the air duct  28 . This opening in the bearing cover  32  is connected via a coupling part  26  to the air duct  28 , making it possible to achieve mobility of the common component  16  relative to the bearing cover  32  and to the metering drum sleeve  24 . 
     The apparatus  8  described for metering pulverulent filling material operates as follows. The metering wheel  11  is suitable precisely for metering small quantities of powder in the pharmaceutical sector. The quantity of pulverulent filling material to be metered is determined by the volume of the metering chamber  13 . This volume of the metering chamber  13  can be adjusted by means of the movement of the common component  16  relative to the metering drum sleeve  24 . The filling material, e.g. powder or pellets, to be dispensed is situated in a filling funnel (not shown). The container situated underneath said funnel is bounded at the bottom opening thereof by the metering drum sleeve  24  of the metering wheel  11  and, in the running direction, by a powder doctor (likewise not shown). The metering wheel  11  can be cantilever-mounted or, alternatively, can be supported by a counter bearing. The metering wheel  11  is driven by a drive shaft. In a filling position, the metering wheel  11  is arranged underneath a filling material container in such a way that the metering chambers  13  can be filled with filling material. To assist the filling process, a vacuum across the filter  12  is built up via the air duct  28 , sucking the filling material into the metering chambers  13  as far as the filter  12 . Here, the filter  12  prevents the filling material from entering the air duct  28 . It should be noted that other filling methods, e.g. those based on mechanical means or exclusively on gravity, can also be used to fill the metering chambers  13 . 
     Once the metering chambers  13  are filled, the metering wheel  11  is turned through 180°, with the result that the metering chambers  13  are arranged in a dispensing position. In the dispensing position, the air duct  28  is connected to a pressure connection, with the result that compressed air flows through the filter  12  and forces out the filling material in the metering chambers  13 . In this case, containers to be filled (not shown) are arranged underneath the metering wheel  11 , and the filling material is then dispensed into said containers. The containers can be, for example, open capsules, which are arranged on a conveyor belt or on a segment for the bottom half of a capsule and are conveyed onward after filling. Since a plurality of common components  16  is provided in the metering wheel  11 , preferably four in the illustrative example, the metering wheel  11  is always turned stepwise as far as the next common component  16 , thereby enabling the particular metering chambers  13  that are at the top to be filled, while the filled metering chambers  13  at the bottom are emptied again. 
     The common component  16  is embodied as a format-specific component. In particular, it comprises a plurality of sleeve projections  18  arranged in series in the axial direction, each of which is open toward the cavity  19 . The side faces of the common component  16  are oriented in such a way relative to the guide surfaces  15  of the guide means  14  that they make possible radial adjustment of the common component  16  with the integrated sleeve projections  18 . The bottom surface of the common component  16 , said surface being oriented in the direction of the center of the metering wheel  11 , interacts with a cam of the adjusting means  10  for radial adjustment. The adjusting means  10  is rotatably mounted and can be turned by means of a corresponding adjusting hub with an associated adjusting wheel. If the metering volume of the metering chamber  13  is to be reduced, the cam of the adjusting means  10  pushes the common component  16  further out. As a result, the outer surface of the sleeve  18  slides into the opening in the metering drum sleeve  24 . If the metering volume is to be increased, the cam is turned in such a way that the spring means  30  move the common component  16  closer to the center of the metering wheel  11 . For this purpose, the spring means  30 , which is held by the guide means  14 , presses against the shoulder  17  of the common component  16 . As an alternative, it would also be possible to provide a spring  30 ′ which was supported on a surface of the guide means  14  that was further out and pressed against a shoulder of the common component  16  formed further in the direction of the center of the metering wheel  11  in order to exert the desired force toward the center of the metering wheel  11 . 
     The cavity  19  of the common component  16 , said cavity being of substantially rectangular design, serves to accommodate and guide the supporting means  20  arranged therein. The supporting means  20  presses the filter  12 , which is to be arranged on the upper side thereof, toward the underside of the metering chamber  13  and the corresponding openings in the common component  16 . There is furthermore a central air duct  28 , via which the corresponding openings  21  and filter  12  arranged therebetween the metering chambers  13  can be supplied with compressed air or a vacuum. Compressed air is introduced if the filled metering chamber  13  is to be discharged in order to transfer filling material into the container to be filled underneath the metering wheel  11 . Compressed air can likewise be provided in order to unclog the filters  12  at a cleaning station in a cleaning position, e.g. in the horizontal state. Via the air duct  28 , a vacuum is applied to the metering chamber  13  in order to assist the sucking in of the filling material. The air supply can be introduced by means of a slip ring or of a rotary union and can be partially controlled. A plurality of common components  16  is provided, each comprising a plurality of sleeve projections  18  for a plurality of metering chambers  13 . However, a different number than the four common components  16  shown is also possible. 
     It is possible for just a single filter  12 , which is of rectangular design, to be provided for a plurality of metering chambers  13  of a common component  16 . Replacement of the filter  12  is also very easy, a process involving loosening the supporting means  20  so that it moves in the direction of the center of the metering wheel  11 . As a result, the filter  12  is no longer clamped but can be removed easily at the side for exchange. After the filter  12  has been changed, the clamping means  22  can be reactivated, the result being that the supporting means  20  press radially outward against the underside of the filter  12  again. 
     The construction of the metering apparatus  8  is also simplified, in particular by the provision of the common component  16 . This can now be introduced into the corresponding guide surfaces  15  as a preassembled unit with a filter  12  and supporting means  20 . The spring means  30  are then fitted in guide means  14 , pressing on the shoulders  17  of the common component  16 . The metering drum sleeve  24  of the corresponding openings is then connected to the upper side of the guide means  14  and secured laterally with corresponding bearing covers  32 . 
     The apparatus  8  is suitable particularly for metering pulverulent filling material but is not restricted thereto. “Pellets”, very small spherical components, can also be dispensed by means of the apparatus  8 .