Patent Publication Number: US-6656412-B2

Title: Compaction system for particles in particle filled cavities of an article

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to methods and apparatus for firmly packing particles or granules in spaced cavities of an article or articles such as cigarette filter rods being moved along a manufacturing line. 
     BACKGROUND OF THE INVENTION 
     Certain articles of manufacture such as charcoal cigarette filters, individual-size packets of granular food products or condiments, capsuled pharmaceuticals, ammunition and the like may require that cavities be completely filled with particles or granules, with the particles being compacted to a desired density or firmness. Several methods exist for adding particles to empty cavities in an article such as a combined filter rod for a cigarette, or other article or articles having spaced cavities. In a cigarette filter rod, for example, cavities to be filled with particles can be spaced in between other filter components. One method for filling the cavities in a cigarette filter rod with particles includes showering the entire filter rod with the particles to allow the particles to fill the spaced cavities. Another method of filling the cavities with particles includes a lug chain that follows the rod as it travels and deposits particles through the lugs into the cavities. Yet another method of filling the cavities with particles uses a pocketed vacuum wheel. The pocketed wheel is driven in synchronization with the filter rod and has internal vacuum which pulls particles into the pockets. As each pocket reaches a corresponding filter rod cavity, the particles are blown from the wheel pocket into the filter rod cavity. With the methods described above, the particles fill the cavities loosely and can result in a difference in the firmness of the rod when the filter component sections of the rod spaced in between the cavities have a different density than the particle filled cavity sections. The difference in density or firmness of the particle filled cavities can present a quality control problem when a consistent firmness for the entire article having the cavities or a consistent firmness from one particle filled cavity to another within an article is desired. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention provide methods and apparatus for firmly packing particles or granules in spaced cavities along an article being moved along a manufacturing line. One or more packing mechanisms can be provided downstream of an initial particle filling station in the direction of movement of an article having cavities to be filled with particles or granules. In an embodiment wherein the article with cavities is a combined cigarette filter rod, examples of packing mechanisms for firmly packing the particles in spaced cavities along the filter rod can include a lugged packing wheel, a smooth packing wheel, and a lugged packing belt. 
     In the case of a lugged packing wheel or a lugged packing belt, or other device having protruding portions that pack only the particles in the spaced cavities, the lugs or protrusions are spaced at a distance that corresponds to the distance between cavities in the article with particles that need to be packed. The lugs are also moved through rotation of the lugged packing wheel or translation of the lugged packing belt at a speed that is synchronized with the speed of movement of the article having cavities to be packed. The synchronization of movement of the packing instrument with movement of the article having cavities ensures that even packing of the particles or granules in the cavities occurs while avoiding damage to the article. 
     In the case of a combined filter rod or other article having cavities to be filled with particles, side rails can be provided to conform to at least two sides of the article, thereby preventing undesired deformation of the article during the packing process. The side rails in combination with a support rail underneath the article prevent deformation of the article during the packing process while also allowing free movement of the article along the rail support system. An embodiment of the invention can also include the application of vacuum to the support rail. In the case of a combined cigarette filter rod, the porous paper that forms the wrapper of the filter rod allows the vacuum to pull particles into the spaced cavities, thereby helping the compacting process. In additional embodiments, vibration can also be applied to the filter rod or rod support rail to allow the particles to pack tighter as they are being compacted. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like parts are referred to with the same reference numeral, and in which: 
     FIG. 1 illustrates a particle compacting system including a lugged packing wheel; 
     FIG. 1A illustrates a cross-sectional view taken in the direction of arrows A—A in FIG. 1; 
     FIG. 1B illustrates a cross-sectional view taken in the direction of arrows B—B in FIG. 1; 
     FIG. 1C illustrates a cross-sectional view taken in the direction of arrows C—C in FIG. 1; 
     FIG. 2 illustrates a particle compacting system including a packing wheel; 
     FIG. 2A illustrates a cross-sectional view taken in the direction of arrows A—A in FIG. 2; 
     FIG. 2B illustrates a cross-sectional view taken in the direction of arrows B—B in FIG. 2; 
     FIG. 2C illustrates a cross-sectional view taken in the direction of arrows C—C in FIG. 2; 
     FIG. 3 illustrates a particle compacting system using a lugged packing belt; 
     FIG. 3A illustrates a cross-sectional view taken in the direction of arrows A—A in FIG. 3; 
     FIG. 3B illustrates a cross-sectional view taken in the direction of arrows B—B in FIG. 3; 
     FIG. 3C illustrates a cross-sectional view taken in the direction of arrows C—C in FIG. 3; and 
     FIG. 4 illustrates a schematic representation of an axial compacting system according to an embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention provides a system for continuously and rapidly compacting particles or granules within successive cavities along an article to achieve desired density and firmness of the finished product. The system can accommodate rapid movement of the article or articles along the manufacturing line while achieving accurate compaction of the particles in the cavities. Depending on the shape of the cavities that are filled with particles, and the shape of the finished product, the compaction process can be performed in different directions relative to the movement of the article. An article such as a cigarette filter rod that has spaced cavities which are filled with granules or particles in a direction perpendicular to the axis of the rod, can be compacted in a radial direction following the particle filling operation, or alternatively, can be compacted in an axial direction after the cavities have been filled and the wrapping paper has been sealed. In the case of an axially directed compacting operation, plungers could be provided to exert pressure on one end or both ends of a completed length of filter rod having a predetermined number of spaced cavities and filter components. In the case of a radially directed compacting operation, compaction pressure is provided to at least the filled cavities in a direction approximately perpendicular to the movement of the article. This pressure can be provided selectively to only the cavities themselves, or continuously to the entire article including the cavities. 
     Referring initially to FIGS. 1,  1 A,  1 B and  1 C, a particle compacting system that performs compaction in approximately the same direction as the filling of particles is shown for compacting charcoal or carbon particles in a combined cigarette filter rod. The combined cigarette filter rod  20  is moved along a support rail system including a bottom support rail  40  and side support rails  50 , clearly shown in FIGS. 1A,  1 B and  1 C. The cigarette filter rod  20  is made up of alternate filter components  22  such as cellulose acetate filter components and particle filled cavities  24 . The particle filled cavities  24  are filled with loose particles or granules at an initial particle filling station  72 , as shown in FIG.  1 . Although the initial particle filling station  72  is illustrated schematically as simply showering particles over an area of the combined filter rod  20  that includes both filter components  22  and cavities  24 , the particle filling station could also be provided with a pocketed vacuum wheel or other means for applying particles directly to the particle filled cavities  24 . 
     A lugged packing wheel  30  is provided downstream of the initial particle filling station  72 . The lugged packing wheel  30  has individual lugs  32  spaced around its outer circumference. The spacing between lugs  32  corresponds to the spacing between particle filled cavities  24  in the moving cigarette filter rod  20 . The lugged packing wheel  30  is rotated in the direction of arrow B at a rate of speed that is synchronized with the movement of filter rod  20  in the direction of arrow A. Accordingly, as each particle filled cavity  24  passes underneath the lugged packing wheel  30 , individual lugs  32  enter successive cavities and compact the particles  70  in each particle filled cavity  24 . 
     After the particles in particle filled cavities  24  have been compacted by the first lugged packing wheel  30 , the article can continue to be moved further downstream to a second particle filling station  74 , where additional particles  70  can be added to the compacted particle filled cavities  24 . After each of the cavities has been filled sufficiently to achieve 100% filling with additional particles, the article continues to move downstream to an optional second lugged packing wheel  30 ′ having lugs  32 ′. 
     During the compacting process, the forces on the particles  70  in each particle filled cavity  24  would tend to push out the sides of the filter rod  20  if the filter rod  20  was unsupported on its sides, due to the flexibility of the wrapping paper. Accordingly, side rails  50 , shown in FIG. 1B, can be provided to conform to the sides of the filter rod  20  and prevent a distortion in the shape of the cylindrical rod. 
     Although two filling stations and compacting lugged wheels are shown in FIG. 1, one of ordinary skill in the art will recognize that the invention is intended to encompass embodiments that may have only a single filling station and compacting wheel, or more than two filling stations and compacting wheels. 
     A second embodiment of the invention is shown in FIGS. 2,  2 A,  2 B and  2 C, wherein a solid packing wheel  130  is provided downstream of the initial particle filling station  72 . The packing wheel  130  is provided with a constant radius outer circumferential surface, and therefore the packing wheel  130  provides an even compacting force to both particles in the cavities  24  and the filter components  22  in between the cavities  24 . Similarly to the first embodiment shown in FIGS. 1,  1 A,  1 B and  1 C, the compacting system of the second embodiment can be provided with one or more packing wheels,  130 ,  130 ′, and one or more particle filling stations,  72 ,  74 . Side rails  150  and bottom support rail  140  maintain the cylindrical shape of the cylindrical rod  20  during the compacting process. If desired, a vacuum can also be applied through the porous paper forming the outside of the filter rod  20 . The vacuum applied from the support rail would help to pull the loose particles into the cavities  24  and aid in the compacting process. If desired, the vacuum applied from the support rail can also induce air flow around the filter rod or other article being processed to assist in cleaning loose particles or granules that may lie on surfaces of the article surrounding the cavities. 
     A third embodiment of a compacting system for compacting loose particles or granules in spaced cavities along a moving article is shown in FIGS. 3,  3 A,  3 B and  3 C. The third embodiment includes one or more particle filling stations  72 ,  74  and one or more lugged packing belts  230 ,  230 ′ having spaced lugs  232 . The packing belt  230  is driven around the outside circumference of two spaced drive wheels  236 ,  238 . Lugs  232  formed along the lugged packing belt  230  are spaced at a distance that corresponds to the distance between cavities  24  in the article  20  being moved underneath the compacting belt. As with the other embodiments described above, the compacting belt  230  is moved at a speed that is synchronized with the movement of cigarette filter rod or other article  20  so that each lug  232  enters a successive cavity  24  as the article  20  moves underneath the lugged belt. After the particles in each cavity  24  are compacted by the lugged packing belt  230  downstream of the initial particle filling station  72 , an additional particle filling station  74  can fill each of the cavities  24  to the top, and an optional second lugged packing belt  230 ′ provided downstream of the second particle filling station can once again compact the particles in each cavity  24 . 
     A fourth embodiment of a compacting system for compacting loose particles or granules in spaced cavities of a cigarette filter rod  20  is shown schematically in FIG.  4 . The filter rod  20  can be compacted in a direction parallel to its axis by plungers  332 ,  334  actuated to press inwardly against one or both ends of the rod. 
     Side rails  250  and bottom support rail  240 , such as shown in FIG. 3C, ensure that the cylindrical shape of the cigarette filter rod  20  is maintained during the compacting process. One of ordinary skill in the art will recognize that the outer periphery of the article having cavities to be filled does not have to be cylindrical as in the above-described embodiments, but could assume any other desired shape.