Patent Publication Number: US-8109277-B2

Title: Smoking article filter with annular restrictor and downstream ventilation

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 60/905,831, filed on Mar. 9, 2007, the entire content of which is incorporated herein by reference. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a side view of a smoking article including a filter having a flow restricting filter segment of a preferred embodiment, wherein the filter tipping paper has been partially unfolded to reveal internal filter components. 
       FIG. 1B  is a side view of a smoking article including a filter having a flow restricting filter segment and an upstream filter segment, wherein the filter tipping paper has been partially unfolded to reveal internal filter components. 
       FIG. 2  is a side view of a smoking article including a filter having a flow restricting filter segment of a preferred embodiment, wherein the filter tipping paper has been partially unfolded to reveal internal filter components. 
       FIG. 3  provides a general representation of DAPTC combiner arranged to perform combining steps of a preferred method of manufacturing the smoking article. 
       FIG. 4  is a representation of a dual hopper max (DH MAX) which has been adapted to conduct certain further filter combining operations on its drums and to tip pairs of tobacco rods with the resultant combined filters. 
       FIGS. 5 and 6  are representations of those further combining steps and tipping operations that are performed on the DH MAX. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Presently disclosed embodiments provide the benefit of a highly ventilated smoking article with desired amounts of resistance to draw and/or provisions for facilitating high speed cigarette manufacturing utilizing high speed filter rod and cigarette making equipment. 
     Referring now to  FIG. 1A , a preferred embodiment provides a smoking article  10  comprising a tobacco rod  12  and a filter  14  connected with the tobacco rod  12  by a tipping paper  16 . Preferably, the filter  14  comprises an upstream end portion  20  of the tipping paper  16 , a mouthpiece filter segment  22  at a downstream end portion  25  of the filter  14 , and an annular flow restricting filter segment  26  situated between the mouthpiece filter segment  22  and the upstream end portion  20  of the filter  14 . 
     In an embodiment, as shown in  FIG. 1B , a second, upstream filter segment  23  is optionally located upstream of the flow restricting filter segment  26 . Preferably, the mouth filter segment  22  and the optional upstream filter segment  23  are low particulate efficiency filter segments preferably constructed from cellulose acetate tow of about 5.0 denier per filament to about 25 denier per filament (e.g. 6.0 denier, 7.0 denier, 8.0 denier, 9.0 denier, 10.0 denier, 11.0 denier, 12.0 denier, 13.0 denier, 14.0 denier, 15.0 denier, 16.0 denier) and approximately 10,000 to approximately 50,000 total denier (td), such as 35,000 td. Also preferably, the mouth filter segment  22  and the optional upstream filter segment  23  are each independently approximately 5 mm to approximately 10 mm in length. 
     Preferably, the flow restricting filter segment  26  comprises an impermeable insert  18  and an air transmissive tubular portion  30  located upstream of a cavity  46  in which smoke from tubular portion  30  mixes with air supplied by ventilation zone  40  comprised of ventilation holes  75  formed in the tipping paper  16 . 
     In this embodiment, the tubular filter segment  30  is preferably constructed from low density cellulose acetate tow (sometimes referred to as a hollow acetate tube or HAT). Preferably, the HAT is approximately 5 mm to approximately 30 mm in length. More preferably the HAT is approximately 15 mm to approximately 25 mm in length. Also preferably, the HAT is approximately 0.5 mm to approximately 2 mm thick. 
     In another embodiment, the tubular portion  30  can be formed from porous foam, paper or other cellulosic materials so long as the material is air transmissive. The tube  30  can be made via other forming techniques such as molding or extruding the tube or forming a tube with a longitudinal seam. Preferably, the tubular support  30  provides desired firmness throughout length of the filter  14 . 
     Preferably, the flow restriction filter segment  26  is configured to contribute sufficient pressure drop such that the smoking article  10  presents a resistance to draw of at least 40 mm water or greater, preferably in the range of approximately 50 mm to approximately 120 mm water. For example, the flow restrictor insert  18  can have a diameter of approximately 4.0 mm to approximately 8.0 mm and more preferably approximately 5 mm to approximately 7 mm. 
     In an embodiment, an insert  18  is plunged in one end of the tubular portion  30 . Preferably, the insert  18  is constructed of a smoke impermeable material such as plastic, polymer or a metal. Most preferably, the insert  18  is made of a non-permeable material such as high density polyethylene (HDPE), extruded or compressed cellulosic material, and/or a closed-cell foam such as paper-foam, tobacco foam, and/or polyethylene foam. The insert  18  is impermeable to smoke so as to force drawn smoke to flow around the insert  18  and through the permeable tubular portion  30 . 
     In a preferred embodiment, the impermeable material used to form the insert  18  is flavored. Examples of flavorants include licorice, sugar, isosweet, cocoa, lavender, cinnamon, cardamom, apium graveolens, fenugreek, cascarilla, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, mint oils, cassia, caraway, cognac, jasmine, chamomile, menthol, cassia, sage, spearmint, ginger, coriander, coffee and the like. 
     In this embodiment, the insert  18  has tapered ends with end to end symmetry that facilitates high speed filter rod making because the insert  18  works the same whether or not the rod making machine orients one end of the device first or reverses it. 
     Preferably, the cavity  46  is defined by an inner periphery of the tubular segment  30 , and the open space between the upstream end of the mouthpiece segment  22  and the downstream end of the insert  18 . The ventilation zone  40  communicates with the cavity  46  at a location downstream of the flow restrictor insert  18 . 
     In this embodiment, the ventilation zone  40  comprises a plurality of ventilation holes which extend through the tipping paper  16 . Because the tubular segment  30  is formed by an air transmissive material, perforations need not be made in and/or extend through the tubular filter segment  30 . This arrangement facilitates the use of online laser perforation techniques to provide ventilation holes during the manufacture of the smoking article  10 . 
     Manufacture of the smoking articles  10  described above can be facilitated with the use of pre-perforated tipping paper. 
     The ventilation zone  40  is established with a first circumferential row (and optionally second and possibly third rows) of ventilation holes through the tipping paper  16  and optionally the filter tube  30 . Accordingly, air is preferably drawn through the ventilation holes of the ventilation zone  40  and into the cavity  46  defined between the flow restrictor insert  18  and the mouthpiece filter segment  22 . 
     Preferably the ventilation zone  40  is located at a downstream location near or adjacent to the flow restriction filter segment  26  so that air drawn through the ventilation zone  40  is allowed to mix with the mainstream smoke in the cavity  46  before arriving at the mouthpiece filter  22 . 
     Preferably, the distance between the ventilation zone  40  and the mouthpiece filter  22  is at least 5 mm or in the range of approximately 5 mm to approximately 20 mm. 
     Preferably, the ventilation zone  40  achieves a ventilation level of the smoking article of at least about 25% and more preferably at least about 50% to about 90%, e.g. 60%, 70%, or 80%. 
     Optionally, a second zone of ventilation may be located upstream of the flow restriction filter segment  26  in addition to the downstream ventilation zone  40  as described above. 
     Preferred dimensions for an 83 mm smoking article include, for example, a filter length of 27 mm, a mouth end filter segment length of 7 mm, vent holes 12 mm from the mouth end of the smoking article, a tubular portion length of 13 mm, an insert length of 5 mm, and an upstream cellulose acetate filter segment length of 7 mm. 
     Referring now to  FIG. 2 , a smoking article  10  includes a tobacco rod  12  and a filter  14 . Preferably, the filter  14  includes a flow restricting filter segment  26  adjacent the upstream end portion  20  of the tipping paper  16 . Preferably, the flow restricting filter segment  26  has a length of approximately 3 mm to approximately 10 mm, more preferably approximately 3 mm to approximately 7 mm in length. 
     In a preferred embodiment, the flow restricting filter segment  26  includes an insert  18  at least partially surrounded by an air transmissive material  35  such as HAT. In this embodiment, the flow restricting filter segment  26  is upstream of a cavity  46  and a ventilation zone  40 . The cavity is defined by an inner periphery of a tubular segment  30 . The cavity  46  is further defined by the open space between the upstream end of the mouthpiece filter segment  22  and the downstream insert  18 . The mouthpiece filter segment  22  and restrictor segment  26  are contained within the tubular portion  30 . The tubular portion  30  is defined by a thick, stiff paper wrap, such as Parliament® type paper. Preferably, flow restricting filter segment  26  is in a condition of being plunged in the tubular portion  30 . 
     In this embodiment, the insert  18  has end-to-end symmetry, and is plunged into the short hollow acetate tube  35  that is substantially the same length as the insert  18 . Because the insert  18  is impermeable, smoke drawn through the filter is diverted through the air transmissive material of HAT 35, and around the flow restrictor insert  18  and into the cavity  46 . 
     Preferably, the flow restriction filter segment  26  and the mouthpiece filter  22  are spaced by a distance sufficient to reduce impaction of particulate smoke components upon the upstream face of the mouthpiece filter  22 . Preferably, the flow restriction segment  26  is spaced approximately 4 mm to approximately 20 mm from the mouthpiece filter segment  22 , more preferably the flow restriction segment  26  is spaced approximately 5 mm to approximately 15 mm from the segment  22 . 
     In a preferred embodiment, the filter may be constructed from simple combining techniques typically used in the industry for manufacturing cigarettes at high speeds. 
     In the  FIG. 2  embodiment, a desired amount of resistance to draw can be achieved while maintaining the desired degree of high ventilation throughout the puff count. The latter attribute is achieved by placement of the ventilation zone  40  downstream of the flow restrictor  26 . By placing the ventilation zone  40  in spaced apart relation to the mouthpiece filter plug  22 , mixing of air drawn into the filter  14  through the ventilation zone  40  with mainstream smoke drawn from the tobacco rod  12  is facilitated. 
     During smoking, good mixing is evidence by production of uniform stain patterns at the buccal end of the mouthpiece filter  22 . 
     During a puff, mainstream smoke is drawn through around the insert  18 , through the air transmissive material  35  of the tubular portion, and into the cavity  46  where it is mixed with ventilation air that is drawn into the cavity  46  via the ventilation zone  40 . 
     In a preferred embodiment, the ventilation zone  40  comprises a plurality of ventilation holes  75 , which extend through the tipping paper  16 , and optionally, partially into or through the tubular segment  30 . This arrangement facilitates the use of online laser perforation techniques to provide ventilation holes  75  during the manufacture of the smoking article  10 . Other techniques may be used to create the ventilation zone  40  such as using off-line, pre-perforated tipping paper, mechanical perforation, electrostatic perforation and other techniques. 
       FIGS. 3-6  illustrate an exemplary method of manufacturing smoking articles including the flow restriction filter segment  26  of  FIG. 1B . Along flutes of a drum  504  pairs of HAT segments  30  are each respectively situated between opposing pairs of 2-up inserts  18 ,  18 ′ and are pushed together so that a pair of 2-up HAT restrictor assemblies are established on each flute, which assemblies are each 26 mm long. The pairs are then fed or placed into a first hopper  501  of an upstream section  506  of a DAPTC combiner. From the first hopper  501 , the 2-up HAT restrictor assemblies are separated and fed in spaced apart relation onto an endless feed belt  505  of the DAPTC combiner. 
     Similarly, continuous cellulose acetate filter rods are produced and cut into a plurality of CA 6-up/84 mm long rods, which are fed or placed into a second hopper  507  of the DAPTC combiner. During combining operations the 6-up rods are further cut and sorted into 2-up/14 mm segments and placed in alternating relation to the restrictor assemblies on the feed belt  505 . 
     At the downstream travel portion of the feed belt  505  a rotating spacer drum  508  establishes a continuous, closed-up procession  515  of the alternating 2-up restrictor assemblies and 2-up CA segments in mutually abutting, end to end relation with one after another. Downstream of the rotating spacer drum  508 , the procession is transferred onto a ribbon of plug wrap  513 . A garniture belt  509  draws both the procession  515  and the plug wrap  513  through a garniture  511  whereat a plug wrap  513  is wrapped about the procession of plugs  515  so as to form a continuous filter rod  521 . Preferably one or more glue guns  517  apply a desired pattern of glue continuously and/or at spaced locations along the ribbon of plug wrap  513  to retain filter rod  521  in its final form. 
     Downstream of the garniture  511  a cutter  517  severs the continuous rod  521  so as to form a 6-up restrictor/upstream segment assembly (rod)  519 . The 6-up rod  519  preferably comprises the following segments from one end to the other: a 1-up/7 mm CA segment; a first 26 mm/2-up restrictor assembly segment; a 14 mm/2-up CA segment; a second 26 mm/2-up restrictor assembly segment; a second 14 mm/2-up CA segment; a third 26 mm/2-up restrictor assembly segment; and a second, 1-up/7 mm. The 6-up rods  519  are then fed or placed into a first hopper  170  of the dual hopper max. 
     Referring now to  FIGS. 4 and 5 , the 6-up/120 mm rods  519  are then cut into three 2-up rods  521  at drum  222 , then graded at drum  224  aligned at drum  226 , whereupon each are cut centrally and spaced apart into opposing pairs of sub-assemblies along each flute of the drum  232 . Each sub-assembly comprises a 1-up/7 mm CA segment (corresponding to the upstream segment  23  in  FIG. 1B ), an insert  18  and a 1-up HAT segment, whose open end portion is directed inwardly along the respective drum flute. The pairs of sub-assemblies are spaced apart sufficiently to receive 2-up/14 mm CA plugs  523 . 
     The 2-up plugs  523  are constructed from similar cutting grading and aligning operations on 6-up 84 mm long filter rods at drums  242 ,  244  and  246  of the DH MAX represented in  FIG. 4 , with further cut, grade and align operations occurring at or about the drum  248 . 
     Referring back to operations at  238 , the plugs are brought together at drum  250  to form a complete 2-up filter structure  525 , which are then fed in between pairs of spaced apart filter rods  527 , as illustrated in  FIG. 6 , and wrapped with tipping paper  529  in accordance with the usual tipping operations of a dual hopper max to form a completed 2-up cigarette structure  531 . Thereafter, the 2-up cigarette structure  531  is severed and the cigarettes are all aligned at drum  264  whereupon they are directed to a packer  266  from whence they go to a cartoner  268  and to a case packer  270 . 
     In an embodiment, flavorants or colorants can be added to the material surrounding the flow restriction device  26 . Examples of flavorants include licorice, sugar, isosweet, cocoa, lavender, cinnamon, cardamom, apium graveolens, fenugreek, cascarilla, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, mint oils, cassia, caraway, cognac, jasmine, chamomile, menthol, cassia, ylang-ylang, sage, spearmint, ginger, coriander, coffee and the like. 
     The embodiments as shown and described herein provide the benefit of a highly ventilated smoking article with desired amounts of resistance to draw and provisions for facilitating high-speed cigarette manufacturing on conventional cigarette making equipment. 
     It will be understood that the foregoing description is of the preferred embodiments, and is, therefore, merely representative of the article and methods of manufacturing the same. It can be appreciated that variations and modifications of the different embodiments in light of the above teachings will be readily apparent to those skilled in the art. For example, other air-permeable materials could be used to construct the HAT. Accordingly, the exemplary embodiments, as well as alternative embodiments, may be made without departing from the spirit and scope of the articles and methods as set forth in the attached claims.