CA1047351A - Tobacco smoke filter (itf grooved) - Google Patents
Tobacco smoke filter (itf grooved)Info
- Publication number
- CA1047351A CA1047351A CA306,036A CA306036A CA1047351A CA 1047351 A CA1047351 A CA 1047351A CA 306036 A CA306036 A CA 306036A CA 1047351 A CA1047351 A CA 1047351A
- Authority
- CA
- Canada
- Prior art keywords
- filtering material
- rod
- smoke
- bonding zone
- cam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Cigarettes, Filters, And Manufacturing Of Filters (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention provides an apparatus for making smoke filter means comprising, a. a source of a bondable filtering material including a multiplicity of fibrous members, b. means defining an elongated bonding zone, c. means for continuously feeding said filtering material into and through said bonding zone, d. means for feeding a bond activating agent into said bonding zone and into contact with said filtering material at a point intermediate the path of travel of said filtering material through said bonding zone to bond said fibrous members of said filtering material to each other at spaced contact points, thereby forming an elongated, smoke-permeable, rod defining a tortuous path for passage of smoke therethrough, e.
elongated mandrel means having a forward end portion axially positioned within said means defining said bonding zone to define an annular space through which said filtering material must pass, f. means for reciprocating said mandrel means within said bonding zone in timed relationship to the passage of said filtering material through said bonding zone between a first position wherein said forward end portion extends at least as far forwardly in the path of travel of said filtering material as the point at which said filtering material is contacted by said bond activating agent, to thereby produce a smoke-permeable annular wall of bonded fibrous members as said filtering material passes said point, and a second position wherein said forward end portion extends sufficiently rearwardly of said point in the path of travel of said filtering material to permit a portion of said filtering material to extend transversely completely across said bonding zone before reaching said point, to thereby produce a smoke-permeable plug section of bonded fibrous members as said filtering material passes said point, said annular wall and said plug sections being integral with each other, whereby said rod is provided with intermittent inner cavities totally enclosed and surrounded by said annular wall and by plug sections forwardly and rearwardly thereof, g. forming means for forming outer cavity means on the exterior surface of said rod, said forming means producing outer cavity means axially spaced from each other at a position on either side of a transverse axis intermediate each inner cavity means with the surface area of said outer cavity means forming a minor portion of the total exterior surface of said rod, h. means for overwrapping said rod with an overwrapping material so as to juxtapose portions of the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding passage of smoke thereacross, and i. severing means for transversely severing said overwrapped rod at selected locations to form filter elements.
The invention provides an apparatus for making smoke filter means comprising, a. a source of a bondable filtering material including a multiplicity of fibrous members, b. means defining an elongated bonding zone, c. means for continuously feeding said filtering material into and through said bonding zone, d. means for feeding a bond activating agent into said bonding zone and into contact with said filtering material at a point intermediate the path of travel of said filtering material through said bonding zone to bond said fibrous members of said filtering material to each other at spaced contact points, thereby forming an elongated, smoke-permeable, rod defining a tortuous path for passage of smoke therethrough, e.
elongated mandrel means having a forward end portion axially positioned within said means defining said bonding zone to define an annular space through which said filtering material must pass, f. means for reciprocating said mandrel means within said bonding zone in timed relationship to the passage of said filtering material through said bonding zone between a first position wherein said forward end portion extends at least as far forwardly in the path of travel of said filtering material as the point at which said filtering material is contacted by said bond activating agent, to thereby produce a smoke-permeable annular wall of bonded fibrous members as said filtering material passes said point, and a second position wherein said forward end portion extends sufficiently rearwardly of said point in the path of travel of said filtering material to permit a portion of said filtering material to extend transversely completely across said bonding zone before reaching said point, to thereby produce a smoke-permeable plug section of bonded fibrous members as said filtering material passes said point, said annular wall and said plug sections being integral with each other, whereby said rod is provided with intermittent inner cavities totally enclosed and surrounded by said annular wall and by plug sections forwardly and rearwardly thereof, g. forming means for forming outer cavity means on the exterior surface of said rod, said forming means producing outer cavity means axially spaced from each other at a position on either side of a transverse axis intermediate each inner cavity means with the surface area of said outer cavity means forming a minor portion of the total exterior surface of said rod, h. means for overwrapping said rod with an overwrapping material so as to juxtapose portions of the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding passage of smoke thereacross, and i. severing means for transversely severing said overwrapped rod at selected locations to form filter elements.
Description
-'2~
This invention relates to -the production of filter means, and relates more particularly to tobacco smoke filter elements. More specifically, the instant inventive concepts are primarily concerned with producing filter means for cigarettes, although the products of -this invention are generally useful as filters, particularly for tobacco smoking means, whether they be cigarettes, cigars, pipes or the like. Since filters for cigarettes are particularly commercially important, the basic embodiments of the instant invention will be discussed as they relate to the production of filtered cigarettes.
Various prior art techniques are known for making filters for use in connection with cigarettes and the like, although the resultant products, in general, have one or more disadvantages. Perhaps the most important property of a filter means is its efficiency, that is, its ability to remove undesir-able constituents from tobacco smoke. Filtration efficiency is ordinarily measured in terms of the percentage of total particul-ate matter (TPM) removed from the smoke, although there is also some concern for the percentage of gas phase constituents which a filter means is capable of removing. While filtration efficiency is perhaps the most important property of cigarette filter means, other properties must also be considered, including pressure drop, taste, hardness, appearance and cost. It is necessary to produce a filter which satisfies commercial require-ments in each of these areas. Frequently, it is necessarry to comprise certain properties in order to satisfy t~e need for others. For example, the most commonly utili2ed cellulose acetate filter means has a relatively low filtration efficiency ` since i~creased efficiency can only be obtained either by increasing the density of the filter material or the length of the filter element~ both of which produce a pressure drop across the filter which is excessive and unacceptable from a commercial .
r ) 3 ~i L
standpoint. While various suggestions have been made for the production of filter means which have improved filtering proper-ties, most prior art developments have no-t been commercially acceptable either because the resulting filter means have been found to have objectionable "taste" characteristics whereby cigarettes provided with such filtering means fail to satisfy a ]arge segment of the smoking public, or because the techniques and/or the materials utilized in the production of such filter means have increased the cost excessively.
High filtration efficiency is considered by the industry to be removal of 60 percent or more of total particulate matter. Cigarette filters having such properties are presently being produced in accordance with the teachings of U.S. Patents Nos. 3,533,416, 3,599,646, 3,637,407, 3,648,711, 3,805,801 and 3,810,477.
A further development in the production of tobacco smoke filter means is disclosed in commonly assigned Patent No.
3,811,451.
However, it would be commercially desirable -to be able to produce a tobacco smoke filter means having high filtration efficiency, low pressure drop and other satisfactory commercial properties, in a manner which enables the speed~of production to be increased, thereby lowering the cost. It is this area with which the instant invention is concerned.
Therefore, it is a primary object of this invention to provide a cigarette filter means or the like and a method and means for manufacturing same wherein the product has high filtration efficiency, satisfactory pressure drop and other commercial re~uirements, and wherein the me-thod and means utilized enable high speed production of the final product.
A further object of this invention is the provision of a cigarette filter having an inner member with both inner `~ ' )3~
and outer cavities to improve the flow path of tobacco smoke and enable greater utility of the filtering material from which it is made, while simultaneously permitting a conventional plug wrap to be used as an outer member which is substantially continuously supported throughout its length by the inner member so as to avoid the need for an internal glue line as has been required by certain prior art techniques.
~ ~e foregoing object is realized by the production of . cavity means between the inner and outer members of the fil-ter ; 10 element which are limited in extent so as to provlde a major . portion of the outer surface of the inner member which is substantially smooth and basically cylindrical to thereby support the outer member in a uniform manner~
Yet another object of this invention is the provision of methods and means for producing a filter element of the type described wherein the outer cavity may be produced in a high speed ~ashion with equipment that is simple and inexpensive to manufacture and maintain thereby minimizing production costs.
Still another object of this invention is the provision of techniques and devices for practicing such techniques which enable the outer surface of the inner member to be provided with limited cavities in any number of a variety of patterns, all of which satisfy the basic requirement that the major portion of the outer surface of the inner member be relatively smooth and continuoug to uniformly support the outer member.of the assembly.
: Other and further objects of this invention reside in the chemical and physical characteristics of the filter product, as well as the manipulative steps utilized in the production and the various features of construction found in the manufacturing apparatus.
Accordingly, the present invention provides an apparatus ~or making smoke ~ilter means comprising, a. a source of a ;J3~
bondable filtering material includiny a multipliciky of fibrous members, b. means defining an elongated bondin~ ~one, c. means ~or continuously feeding said filtering material into and through said bonding zone, do means for feeding a bond activating agent into said bonding zone and into contact with said filteriny material at a point intermediate the path of travel of said filtering material through said bonding zone to bond said fibrous members of said filtering material to each other at spaced con-tact points, thereby forming an elongated, smoke-permeable, rod de~ining a tortuous path for passage of smoke therethrough, e.
elongated mandrel means having a forward end portion axially positioned within said means defining said bonding zone to define an annular space through which said filtering material must pass, fO means for reciprocating said mandrel means within said bonding ~ zone in timed relationship to the passage of said filtering : material through said bonding zone between a first position .wherein said forward end portion extends at least as far forwardly in the path of travel of said filtering material as the point at ` which said filtering material is contacted by said bond activat-ing agent, to thereby produce a smoke-permeable annular wall of .; , : bonded ~ibrous members as said filtering material passes saidpoint, and a second position wherein said forward end portion extends sufficiently rearwardly of said point in the path of travel of said filterirlg material to permit a portion of said ~ilterlng material to extend transversely completely across said .` bonding zone before reaching said point, to thereby produce a ` smoke-permeable plug section o~ bonded fibrous members as said ~ ~iltering matQrial passes said point, said annular wall and said :`
~ plug sections being integral with each other, whereby said rod , ~
is provided with intermittent inner cavities totally enclosed and surrounded by said annular wall and by plug sections forwardly and rearwardly the~eof, g. forming means for forming outer 1, ' - .:,~.;.. :
.. . .
:: - , . , ; . -;3i~
cavity means on -the exterior surface of said rod, said forming means producing outer cavity means axially spaced from each other at a position on either side of a transverse axis inter-: mediate each inner cavity means with the surface area of said outer cavity means forming a minor portion of -the -total exterior surface of said rod, h. means for overwrapping said rod with an overwrapping material so as to juxtapose portions oE the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding 10 passage of smoke thereacross, and i~ severing means for trans-;~ versely severing said overwrapped rod at selected locations to ;~ form filter elements.
The invention will now be described in more detail, by way of example only, with reference to the accompanying . drawings, wherein:
Figure 1 is an enlarged perspective view of one form of filtered cigarette produced according to the instant invention, parts being broken away for illus~rative clarity and convenience;
` Figure 2 is a schematic view of a method and means for making filter elemen~s according tG the instant inventive concep~s;
Figure 3 is a fragmentary view of a filter rod pro-;. duced according to this invention, parts being in section and parts being broken away for illustrative clarify;
Figure 4 is a transverse cross-sectional view through , the filter element of the filtered cigarette of Figure 1, taken ~ subs~antially along lines 4-4 of Figure l;
-`~ Figure 5 is an enlarged cross-sectional view through ~one mechanism for forming elongated grooves in the outer surface of the inner filter member according to this invention;
Figure 6 is a transverse cross-sectional view taken substantially along lines 6-6 oE Figure 5;
. - 5 -~ .
Figure 7 is a cross-sectional view, similar to Figure 6, through a means for forming the grooves in the inner filter member by intermittent jets of steam;
Figure 8 is a transverse cross-sectional view taken substantially along lines 8-8 of Figure 7, partially broken away for illustrative clarity;
Figure 9 is an enlarged fragmentary detail showing the valve mechanism in -the device of Figures 7 and 8;
Figure 10 is a sectional view through a portion of the processing apparatus which produces an elongated rod with discrete internal cavities, an alternate position of the recipro-cating mandrel used therewith being shown in dotted lines;
Figure 11 is a view similar to Figure 1 through a filtered cigarette according to a second embodiment of this invention whrein the outer cavity means of the inner member has a knurled-like configuration;
Figure 12 is a longitudinal view, partially in section, of a filter rod incorporating filter elements of the type shown in Figure 11;
Figure 13 is an enlarged schematic view of a portion of the knurled--like surface of the filter element shown in Figure 11;
Figure 14 is a perspective view, similar to Figures 1 and 11, of a still further modified filtered cigarette includ-ing a filter element according to this invention wherein the outer cavity means is in the form of a continuous helical groove;
Figure 15 is a fractional elevational view of a fil~er rod from which filter elements as shown in Figure 14 are produced;
Flgure 16 is an enlarged fragmentary view of a crimping wheel useful in producing a ilter element of the type shown in Figure l;
.
,~ ' 7~
Figure 17 is a schematic fragmentary cross-sectional view showing the manner in which a multiplicty of crimping wheels - of the type shown in Figure 16 would be used in the production of a filter rod;
Figure 18 is a view similar to E'igure 16 of a portion of a crimping wheel useful in the production of a filter element -; of the type shown in Figure 11;
Figure 19 is a view similar to Figures 16 and 18 o~
a portion of a crimping wheel useful in the production of a filter element of the type shown in Figure 1~; and Figure 20 is a view similar to Figure 1 of yet another embodiment of a filtered cigarette within the scope of this invention.
Like reference characters refer to like parts through-out the several views oE the drawings.
Referring now to the drawings, and more particularly to Figure 1~ a ~iltered cigarette according to the instant `, inventive concepts is designated generally by the reference numeral 20 and comprises basically a tobacco rod shown partially at 22 and a filter element according to one embodiment o~ this nvention designated generally by the reference numeral 24, a conventional tipping overwrap being shown in dotted lines at 26 securing the tobacco rod and the filter element in end-to-end relationship according to well known prior art techniques.
The filter element 24 comprises basically an axially elongated, hollow, outer element 28 formed by conventional plug wrap as will be explained hereinafter in more detail and an ~ axially elongated inner member 30 disposed wi-thin the outer ,~ member 28.
~ The inner member 30 is preferably and primarily formed from a continuous tow of cellulose acetate ~ilamentary material, although other ~iltering material may be used with ''' ' ';
.... __ ; - - = - - - - -.~ . . . .
~ ~f~
slight modifica-tlons. For example, filamentary tow forme~ of other materials such as polyethylene, polypropylene and the like or even non-woven staple fibers of the type described in some detail in U.S. Patents Nos. 3,297,041 and 3,552,400 may also be used. In fact, it is possible to produce filter elements accord-ing to ~his inventlon from an extruded, open celled, foam material, such as cellulose acetate foam or the like. However, since cellulose acetate filamentary tow is the presently pre-ferred material from a commercial standpoint, the remainder of this specification will be directed ~o the use of such material.
Thus, the inner member 30 is preferably formed of crimped filamentary cellulose acetate members bonded together at their contact points to form a smoke-permeable element defining a tortuous path for passage of smoke therethrough.
- Filtering material of this nature is well known, as are techniques for producing same.
As will be seen from Figures i and 4, integral cir-cumferentially continuous peripheral portions of the outer surface of the inner member 30 are juxtaposed to portion of the inner surface of the outer member 28 to a-t least substantially preclude axial passage of smoke across the area therebetween.
Such an arrangement is shown at both ends of the inner and outer members in the embodiment of Figure 1, since the grooves to be discussed in more detail hereinafter terminate short of the ends of this element. However, it is to be understood tha-t the instant invention covers an arrangement wherein the grooves to be discus~ed further hereinafter extend to the end of the filter element opposite from the inner cavity, also to be discussed in more detail hereinafter.
According to a basic feature of this invention, limited portions of the remaining outer surface of the inner ; member 30, excluding the continuous peripheral portions 32, 34, :, .
: - , . . .~ . .
.. . ..
73S~
are spaced from the inner surface of the oute~ member 28 to define outer cavity means therebetween which offer less resistance to passage of smoke ~han the filtering material of the inner member, as well as the areas at which the outer surface of the inner member and the inner surface of the outer member are juxta-posed. In the embodiment of Figures 1, 3 and 4, -these limited portions are shown as axially elongated, circumferentially spaced, grooves 36 which together define the outer cavity means of the inner member 30.
It should be understood that these grooves have been exaggerated in the drawings for illustrative clarity and that they ar~, in fact, preferably substantially smaller in circum-ferential extent than the illustrated embodiments. Moreover, although 8 grooves have been shown, any number of external grooves may be utilized so long as the remaining requirements of this invention are maintained. In fact, a preferred embodiment of this invention utilizes 16 such grooves as will be described subsequently.
A critical feature of this invention resides in the fact that the major portion of the total outer surface of the inner member 30, includin~ the peripheral portions 32, 34, is ; ~uxtaposed to the inner surface of the outer member 28 to provide substant.ially uniform support to the outer member 28 by the inner member 30 throughout its length. Thus, the outer cavity means must be limited in nature such that the remaining outer surface of the inner member 30 is substantially smooth and continuous.
~` For example, the outer cavity means can comprise from about 5 to no more than 50 percent of the total outer surface of the inner member 30 without departing from the .instant inventive concepts, with a proportion of 20 to 30 percent being considered optimum.
By thus providing substantially uniform continuous support for the outer member 28 over its entire length it is _ 9 _ . ... . . . .
~ 3~
possible to use a lighter weight plug wrap for the outer member 28 than is required when substantially greater portions of the inner member are spaced from the outer member as, for example, in a filter of the type shown in U~S. Patent No. 3,533,416.
Moreover, this subs-tantially uniform support precludes the need for an internal glue line between the inner and outer members as has been necessary with prior art techniques. Additionally, by avoiding significant crimping of the inner member according to the instant invention, substantially more of the filtering 10 material is available -to perform its primary function, that IS, removal of undesirable constituents from the tobacco smoke passing therethrough. Yet, the provision of the limited outer cavity means enables the passage of smoke to be directed uniformly over all of the filtering material of the inner member, thereby further improving filtration efficiency.
Referring again to Figure 1, integral first portions of the inner member 30 extend transversely across the full dia-meter of thP inner member 30 in the form of an uncrimped plug 38 of filtering material defining a tortuous path for smoke therethrough. Integral second portions 40 of the inner member 30 which are axially spaced from the first portions 38, define an area extending across the interior oE the inner member 30 which offers less resistance to passage of smoke than the filtering material, as well as the areas at which the outer surface of the inner member and the inner surface of the outer member are juxtaposed, in the embodiment shown this second area being merely the opening at the end of the inner cavity means 42 between the first and second portions 38, 40, respectively. This inner cavity means 42 offers less resistance to passage of smoke than the filtering material of the inner member 30.
Thus, the path of travel of smolce from the tobacco rod 22 is through the plug section 38 into the grooves 36 which ~7;3 5i~
distribute the smoke uniformly over the surface of the inner member for passage through the filtering material into the inner cavity means 42 to the mouth of the user.
Of course, it is possible to reverse the filter element 24 in the filtered cigarette 20 so that the area 40 ls juxtaposed to the tobacco section 22, rather than the area 38.
In Figure 3 a continuous rod 50 made up of a multiplic-ity of integrally connected filter elements of the type shown at 24 in Figure 1 will be seen. This rod is severed transversely along the lines 52, 54, to produce individual filter elements such as shown at 24. Of course, the rod could be severed at other locations to produce filter elements of multiple length.
Moreover, it is common practice to initially produce double filters which are then secured to two tobacco sections by a common tipping overwrap following which individual filtered cigarettes are formed by severing the double filter at its midpoint.
Reference is now made particularly to Figure 2 for the overall method and means utilized in producing filter elements in accordance with this invention. Basically, this overall technique is similar in many respects to the techniques shown and described in detail in U.S. Patent No. 3,637,44, referred to previously, while other modifications are similar to specific ; elements shown in detail in U.S. Patent No. 3,811,451, also referred to previously. According to preferred embodiments of this invention, the filtering material utilized in production of filter elements is a continuous filamentary tow, dasignated ` generally by the reference numeral 60 which includes a multi-plic1ty oE bondable fibrous members activated by contact with a hot ~luid such as steam. The filtering material 60 is continuous-ly passed into and through an elongated bonding zone 62 which may comprise a conventional stuffer jet and steam head similar .
.
.,, ~735~, in nature to those shown in various o~ the above-mentioned prior art patents. Specifically, the tow is contacted with steam entering through conduit 64, shown in detail in Figure 10, and is then distributed through a multiplicity of circumferentially spaced passageways ~6 into the bonding zone as the filtering material 60 passes therethrough. A mandrel 68 is positioned generally axially o~ the bonding zone to define an annular space through which the filtering material ~0 must pass and the mandrel ~8 is reciprocated between the full line position and the dotted line position in timed relationship to the passage of the filter-ing material, the dotted position being at least as far forward in the path of travel of the filtering material as the point at which the filtering material is contacted by the bond activating agent, namely steam, to thereby produce a smoke-permeable annular wall of bonded fibrous members as the filtering material passes this point, with the full line position of the mandrel 68 being sufficiently rearwardly of the point in the path of travel of the filtering material at which the steam contacts same to permit a portion of the filtering material to extend transversely completely across the bonding zone before reaching this poin~, thereby producing a smoke-permeable plug section of bonded fibrous members as the filtering material passes this point. The annular wall and the plug sections are integral with each other to provide the rod 50 with intermittent inner cavity means 42 totally en-closed and surrounded by the annular wall and by plug sections forwardly and rearwardly thereof, as will be seen particularly in Figure 3.
i ` Following the steam treatment, the rod is cooled at 70, the garniture 72 providing a continuous pulling mechanism drawing the rod through the initial processing stages.
The outer cavity means 36 may be fo~med in the rod 50 by a variety of techniques and devices, one of which is shown .
: . ., , : . .
,, , . . , . ~
.. , ~ , . .
~l735~
broadly at 74 in Figure 2 and illustrated in detail in Figures 5 and 6. Specifically, this mechanical ironing device 74 includes a steam head portion 76 wherein steam enters through conduit 78 and is distributed by circumferentially spaced passage-ways 80 to contact and soften the outer surface o~ the rod 50 as it passes therethrough. The remaining portion 82 of the device 74 comprises forming means for intermittently projecting a ~ plurality of radially extending, circumferen~ially spaced, pins 84 into contact with the rod 50 as it is continuously moved past said pins by the additional garniture means 86. In this embodi-ment, a guide member 88 forms an axial bore 90 for passage of the rod 50 and supports the pins 84 in radial extending passage-ways which each have an enlarged section slidingly carrying cam followers 92 each of which carries one of the pins 84. The cam followers 92 are biased outwardly by spring means 94 to engage a cam surface of a cam ring 96, which cam surface includes first portions 98 for pressing the pins 84 radially inwardly to project the ends thereof into the bore 90 and alternating second portions 100 which permit the pins 84 to move radially outwardly so that their ends are withdrawn from the bore 90. Any conventional means, such as the gear teeth 102, may be provided for rotating the cam ring 96 as shown by the arrow in Figure 6, so that the first and second portions 98, 100 alternately engage the cam i followers ~2.
Of course, the cam surface is designed so as to form the grooves 36 over only a limited portion of the outer surface I of the rod as it passes through the device 74. For example, a presently preferred embodiment utilizes 16 equally spaced pins each having a diameter of 1/32 inch which, due to the inherent resiliency of the material of the inner member actually produce grooves having a circumferential extend or width of only about 0.02Q inch~ The groove can have any radial extent or depth, ., .
. .
~`9~35~
short of engaging the inner cavity ~2, although shallow grooves e.g., approximately 0.020 inch, are fully satisfactory. The axial extent or length of the grooves in the preferred embodiment is approximately 2/3 of the total axial extent of the inner member, terminating equidistant Erom each end of the inner mernber.
As an example cf how limited the outer cavity may be in order to provide a substantially smooth outer surface while still assisting in distribution of the smoke over the entire filtering material, the grooves may even be formed from a plurality of circumferentially spaced radially extending, razor blades. Thus, only a limited break in the sealed peripheral areas is necessary to improve overall use of the filtration material.
Turning again to Figure 2, once the outer cavity means 36 have been formed, the rod 50 is overwrapped in the garniture means 86 with a conventional plug wrap, a source of which is shown at 104.
Finally, the rod is severed transversely at selected locations in a cutting means shown schematically a~ 106.
An alternate technique for defining the grooves 36 is by intermittently projecting jets of steam into contact with the outer sur~ace of the rod 50 as it is moved past such jets. A
mechanism for forming the grooves 36 in this manner is seen particularly in Figures 7-9, this arrangement being similar to the mechanism shown in Figures 5 and 6, like parts being designat-ed by the same re~erence numeral followed by the suffix "a" to facilitate an understanding of this device. ~he guide means 88a includes portions defining a plurality of radially extending, circumferentially spaced, passageways 110 communicating with the bore 90a. Steam is fed through a conduit 112 to the passageways 110, with the cam followers 92a carrying valve means 114 at their radially inward ends. The valve means comprise vents 116 which in thelr radially inward position communicate with the conduit .. . . . .. . . . ... . . . .
~'73S:~L
112 and vent the steam to the atmosphere whereas, in the radially outward position of the valve means 114 shown in Figure 9, the conduit 112 is in communication with the passageways 110 so that jets of steam are intermittently projected into the bore 90a.
The remainder of this device func-tions in a manner similar to the device of Figures 5 and 6.
In addi-tion to either of the techniques shown pre-viously for forming the external grooves 36, crimping wheels similar to those shown in Figures 10-13 of U.S. Paten~ No.
3,637,447 may be used. A portion of one such crimping wheel is shown in Figure 16 at 120 and will be seen to comprise crimping portions 122 having raised projections 124 corresponding to the grooves 36 with intermittent recessed portion 126 which function to form the uncrimped peripheral portions 32, 3~ of the individual filter elements. A multiplicity of such crimping wheels may be used in combination as shown in Figure 17 to simultaneously form all of the grooves around the peripheral surface of the rod 50 as they engage the rod~
A modified form o~ ~iltered cigarette and filter rod according to the instant inventive concepts is shwon in Figures 11-13. Except for the external cavity means, this embodiment is substantially identical with the embodiment of Figures 1, 3 and ~ and, therefore, similar parts have been designated by the same reference numeral followed by a suffix "b". In this embodiment ` the outer cavity means 36b is defined by a plurality of inter-~connecting axially and circum~erentiall~ extending outer cavities defining a knurled-like outer sur~ace shown in detail in Figure ~3. Of course, it is important that the knurled-like portion be so defined that a major part of the outer surface of the inner member 30b be in contact with, and support, the inner surface of the outer member 28b.
This knurled-like surface may be formed in any con-,~ ' , . . . ... .. .
:, .. ~ . , . : .
'3~i~
ventional manner such as, by the use of crimping wheels, a portion of one of which is illustratively shown at 130 in Figure 18.
Alternatively, vacuum means may be utilized to pull portions of the outer surface of the inner member 30b radially o~t~ardly leaving the remaining surface portions to form the outer cavity in a knurled-like pattern.
Similarly, a further embodiment of the instant inventive concept is shown in Figures 1~ and 15, wherein parts similar to those of the embodiment of Figures 1, 3 and 4 are designated by the same reference numeral followed hy a suffix "c". It will be seen from Figures 14 and 15 that the ou-ter cavity means 36c are in the form of a continuous helical groove.
This helical groove can be formed in any conventional ~; manner, such as, for example, by a multiplicity of crimping :~ wheels, a portion of one of which is shown illustratively at 140 in Figure 19.
Other patterns for the outer cavity means will be readily recognized by those with ordinary skill in the art, as will techniques and devices for producing same.
Although the outer cavity means can be formed by a crimping technique, it will be seen that crimping of this nature is not as extensive as with the production of prior art Eilter devices such as those shown in the various above-identiEied , patents. With a substantial crimping of the filter rod, the rod ; is frequently distorted requiring the use of a relatively heavy-weight plug wrap to force it back into its round shape. The use of such heavier material, of course, increases the cost. Moreover, ~ substantiaI crimping of the filter elements renders the crimped i portions relatively useless as a filtering medium, thereby reducing the overall efficiency of the final product.
The following data compares certain characteristics oE products made according to the instant inventive concepts . ~' -~7935~
designated as "I" and "II" with produc-ts according -to prior art techniques, a single filter element of the type shown, for example in U.S. Patent No. 3,637,447 being designa-ted at "III" and a double filter element of the ~ype shown in U.S. Patent No.
3,805,801 being designated as "IV" in the table below.
Percent Type Weight Pressure Drop Retention I 11.5 gms 2.7" 71.8 II 11.7 gms 2.8" 70.8 III 16.5 gms 2.8" 69 IV 13~ gms 2.8" 65 It will be seen from the above that filter elements prepared according to the instant inventive concepts compare ; favorably with the prior art filters with respect to pressure drop, while pxoviding at least as good as, and frequently better, ~iltration efficiency with less material. Other commercially significant properties such as hardness, taste and the like also compare favorably with prior art filter elements.
Although the outer member 28 in the various embodiments described hereinabove has been the plug wrap and the inner member 30 has been formed entirely of a filtration material such as cellulose acetate tow or the like, a further possible modification within the instant inventive concepts utilizes the plug wrap as a part of the filtration material. Reference is made to Figure 20 wherein such an embodiment is shown with parts similar to previous embodiments bearing the same reference numeral followed by a suffix "d".
Porous or smoke-permeable plug wraps are well known and are commercially available under various trade designations, e.g., Ecusta Ref. #2961~ or Schweitzer Ref. #638-63-1. When using a material of this type it is possible to overwrap the cellulose acetate rod with porous plug wrap prior to forming the ;
7~
outer cavity means. Thus, if desired, in a sys-tem such as the one shown in Figure 2, the porous plug wrap may be secured about the cellulose ace-tate rod in the garniture means 72 as shown in dotted lines at 104' rather than in the garniture means 86 as shown in full lines at 104. Then, outer cavity means such as a plurality of circumferentially spaced, axially extending grooves 36d may be formed such as by crimping wheels or the like in the outer surface of this composite inner member, that is, the cellulose acetate rod 24d covered wi-th porous plug wrap 28d.
Preferably such grooves would extend completely over the plug sections 34d of the cellulose acetate rod and terminate short of the midsections of the inner cavity means 42d. With an "inner member" of this type, the tipping overwrap 26d used -to join the filter section of the tobacco section functions as the "outer member" of the filter element 20d. Thus, the use of the terms "inner member" and "outer member" herein and in the appended , claims is to be understood as being broad enough to include an ; arrangement wherein the "inner member" is a composite element including a porous plug wrap and the "outer member" is the tipping 20 overwrap. With such a construction the smoke passes through the~
inner and outer cavity means, as well as the porous plug wrap and the cellulose acetate filtration material of the inner member affording even further filtration resulting from the presence of the plug wrap in the smoke path.
It will now be seen that there is herein provided a smoke fllter and method and means for manufacturing same which satisfies the various objectives set forth previously, and which provide significant advantages of a commercial nature. While this invention has been described with reference to presently : : ..
~` 30 preferred exemplary embodiments thereof, it should be clearly .
, ~ understood that the invention is not limited thereto, but may be variously practiced within the scope of the following claims.
;
'735~
This application is a divisional application from application No. 254,767 filed on June 14, 1976.
. .
:
, ' '~
This invention relates to -the production of filter means, and relates more particularly to tobacco smoke filter elements. More specifically, the instant inventive concepts are primarily concerned with producing filter means for cigarettes, although the products of -this invention are generally useful as filters, particularly for tobacco smoking means, whether they be cigarettes, cigars, pipes or the like. Since filters for cigarettes are particularly commercially important, the basic embodiments of the instant invention will be discussed as they relate to the production of filtered cigarettes.
Various prior art techniques are known for making filters for use in connection with cigarettes and the like, although the resultant products, in general, have one or more disadvantages. Perhaps the most important property of a filter means is its efficiency, that is, its ability to remove undesir-able constituents from tobacco smoke. Filtration efficiency is ordinarily measured in terms of the percentage of total particul-ate matter (TPM) removed from the smoke, although there is also some concern for the percentage of gas phase constituents which a filter means is capable of removing. While filtration efficiency is perhaps the most important property of cigarette filter means, other properties must also be considered, including pressure drop, taste, hardness, appearance and cost. It is necessary to produce a filter which satisfies commercial require-ments in each of these areas. Frequently, it is necessarry to comprise certain properties in order to satisfy t~e need for others. For example, the most commonly utili2ed cellulose acetate filter means has a relatively low filtration efficiency ` since i~creased efficiency can only be obtained either by increasing the density of the filter material or the length of the filter element~ both of which produce a pressure drop across the filter which is excessive and unacceptable from a commercial .
r ) 3 ~i L
standpoint. While various suggestions have been made for the production of filter means which have improved filtering proper-ties, most prior art developments have no-t been commercially acceptable either because the resulting filter means have been found to have objectionable "taste" characteristics whereby cigarettes provided with such filtering means fail to satisfy a ]arge segment of the smoking public, or because the techniques and/or the materials utilized in the production of such filter means have increased the cost excessively.
High filtration efficiency is considered by the industry to be removal of 60 percent or more of total particulate matter. Cigarette filters having such properties are presently being produced in accordance with the teachings of U.S. Patents Nos. 3,533,416, 3,599,646, 3,637,407, 3,648,711, 3,805,801 and 3,810,477.
A further development in the production of tobacco smoke filter means is disclosed in commonly assigned Patent No.
3,811,451.
However, it would be commercially desirable -to be able to produce a tobacco smoke filter means having high filtration efficiency, low pressure drop and other satisfactory commercial properties, in a manner which enables the speed~of production to be increased, thereby lowering the cost. It is this area with which the instant invention is concerned.
Therefore, it is a primary object of this invention to provide a cigarette filter means or the like and a method and means for manufacturing same wherein the product has high filtration efficiency, satisfactory pressure drop and other commercial re~uirements, and wherein the me-thod and means utilized enable high speed production of the final product.
A further object of this invention is the provision of a cigarette filter having an inner member with both inner `~ ' )3~
and outer cavities to improve the flow path of tobacco smoke and enable greater utility of the filtering material from which it is made, while simultaneously permitting a conventional plug wrap to be used as an outer member which is substantially continuously supported throughout its length by the inner member so as to avoid the need for an internal glue line as has been required by certain prior art techniques.
~ ~e foregoing object is realized by the production of . cavity means between the inner and outer members of the fil-ter ; 10 element which are limited in extent so as to provlde a major . portion of the outer surface of the inner member which is substantially smooth and basically cylindrical to thereby support the outer member in a uniform manner~
Yet another object of this invention is the provision of methods and means for producing a filter element of the type described wherein the outer cavity may be produced in a high speed ~ashion with equipment that is simple and inexpensive to manufacture and maintain thereby minimizing production costs.
Still another object of this invention is the provision of techniques and devices for practicing such techniques which enable the outer surface of the inner member to be provided with limited cavities in any number of a variety of patterns, all of which satisfy the basic requirement that the major portion of the outer surface of the inner member be relatively smooth and continuoug to uniformly support the outer member.of the assembly.
: Other and further objects of this invention reside in the chemical and physical characteristics of the filter product, as well as the manipulative steps utilized in the production and the various features of construction found in the manufacturing apparatus.
Accordingly, the present invention provides an apparatus ~or making smoke ~ilter means comprising, a. a source of a ;J3~
bondable filtering material includiny a multipliciky of fibrous members, b. means defining an elongated bondin~ ~one, c. means ~or continuously feeding said filtering material into and through said bonding zone, do means for feeding a bond activating agent into said bonding zone and into contact with said filteriny material at a point intermediate the path of travel of said filtering material through said bonding zone to bond said fibrous members of said filtering material to each other at spaced con-tact points, thereby forming an elongated, smoke-permeable, rod de~ining a tortuous path for passage of smoke therethrough, e.
elongated mandrel means having a forward end portion axially positioned within said means defining said bonding zone to define an annular space through which said filtering material must pass, fO means for reciprocating said mandrel means within said bonding ~ zone in timed relationship to the passage of said filtering : material through said bonding zone between a first position .wherein said forward end portion extends at least as far forwardly in the path of travel of said filtering material as the point at ` which said filtering material is contacted by said bond activat-ing agent, to thereby produce a smoke-permeable annular wall of .; , : bonded ~ibrous members as said filtering material passes saidpoint, and a second position wherein said forward end portion extends sufficiently rearwardly of said point in the path of travel of said filterirlg material to permit a portion of said ~ilterlng material to extend transversely completely across said .` bonding zone before reaching said point, to thereby produce a ` smoke-permeable plug section o~ bonded fibrous members as said ~ ~iltering matQrial passes said point, said annular wall and said :`
~ plug sections being integral with each other, whereby said rod , ~
is provided with intermittent inner cavities totally enclosed and surrounded by said annular wall and by plug sections forwardly and rearwardly the~eof, g. forming means for forming outer 1, ' - .:,~.;.. :
.. . .
:: - , . , ; . -;3i~
cavity means on -the exterior surface of said rod, said forming means producing outer cavity means axially spaced from each other at a position on either side of a transverse axis inter-: mediate each inner cavity means with the surface area of said outer cavity means forming a minor portion of -the -total exterior surface of said rod, h. means for overwrapping said rod with an overwrapping material so as to juxtapose portions oE the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding 10 passage of smoke thereacross, and i~ severing means for trans-;~ versely severing said overwrapped rod at selected locations to ;~ form filter elements.
The invention will now be described in more detail, by way of example only, with reference to the accompanying . drawings, wherein:
Figure 1 is an enlarged perspective view of one form of filtered cigarette produced according to the instant invention, parts being broken away for illus~rative clarity and convenience;
` Figure 2 is a schematic view of a method and means for making filter elemen~s according tG the instant inventive concep~s;
Figure 3 is a fragmentary view of a filter rod pro-;. duced according to this invention, parts being in section and parts being broken away for illustrative clarify;
Figure 4 is a transverse cross-sectional view through , the filter element of the filtered cigarette of Figure 1, taken ~ subs~antially along lines 4-4 of Figure l;
-`~ Figure 5 is an enlarged cross-sectional view through ~one mechanism for forming elongated grooves in the outer surface of the inner filter member according to this invention;
Figure 6 is a transverse cross-sectional view taken substantially along lines 6-6 oE Figure 5;
. - 5 -~ .
Figure 7 is a cross-sectional view, similar to Figure 6, through a means for forming the grooves in the inner filter member by intermittent jets of steam;
Figure 8 is a transverse cross-sectional view taken substantially along lines 8-8 of Figure 7, partially broken away for illustrative clarity;
Figure 9 is an enlarged fragmentary detail showing the valve mechanism in -the device of Figures 7 and 8;
Figure 10 is a sectional view through a portion of the processing apparatus which produces an elongated rod with discrete internal cavities, an alternate position of the recipro-cating mandrel used therewith being shown in dotted lines;
Figure 11 is a view similar to Figure 1 through a filtered cigarette according to a second embodiment of this invention whrein the outer cavity means of the inner member has a knurled-like configuration;
Figure 12 is a longitudinal view, partially in section, of a filter rod incorporating filter elements of the type shown in Figure 11;
Figure 13 is an enlarged schematic view of a portion of the knurled--like surface of the filter element shown in Figure 11;
Figure 14 is a perspective view, similar to Figures 1 and 11, of a still further modified filtered cigarette includ-ing a filter element according to this invention wherein the outer cavity means is in the form of a continuous helical groove;
Figure 15 is a fractional elevational view of a fil~er rod from which filter elements as shown in Figure 14 are produced;
Flgure 16 is an enlarged fragmentary view of a crimping wheel useful in producing a ilter element of the type shown in Figure l;
.
,~ ' 7~
Figure 17 is a schematic fragmentary cross-sectional view showing the manner in which a multiplicty of crimping wheels - of the type shown in Figure 16 would be used in the production of a filter rod;
Figure 18 is a view similar to E'igure 16 of a portion of a crimping wheel useful in the production of a filter element -; of the type shown in Figure 11;
Figure 19 is a view similar to Figures 16 and 18 o~
a portion of a crimping wheel useful in the production of a filter element of the type shown in Figure 1~; and Figure 20 is a view similar to Figure 1 of yet another embodiment of a filtered cigarette within the scope of this invention.
Like reference characters refer to like parts through-out the several views oE the drawings.
Referring now to the drawings, and more particularly to Figure 1~ a ~iltered cigarette according to the instant `, inventive concepts is designated generally by the reference numeral 20 and comprises basically a tobacco rod shown partially at 22 and a filter element according to one embodiment o~ this nvention designated generally by the reference numeral 24, a conventional tipping overwrap being shown in dotted lines at 26 securing the tobacco rod and the filter element in end-to-end relationship according to well known prior art techniques.
The filter element 24 comprises basically an axially elongated, hollow, outer element 28 formed by conventional plug wrap as will be explained hereinafter in more detail and an ~ axially elongated inner member 30 disposed wi-thin the outer ,~ member 28.
~ The inner member 30 is preferably and primarily formed from a continuous tow of cellulose acetate ~ilamentary material, although other ~iltering material may be used with ''' ' ';
.... __ ; - - = - - - - -.~ . . . .
~ ~f~
slight modifica-tlons. For example, filamentary tow forme~ of other materials such as polyethylene, polypropylene and the like or even non-woven staple fibers of the type described in some detail in U.S. Patents Nos. 3,297,041 and 3,552,400 may also be used. In fact, it is possible to produce filter elements accord-ing to ~his inventlon from an extruded, open celled, foam material, such as cellulose acetate foam or the like. However, since cellulose acetate filamentary tow is the presently pre-ferred material from a commercial standpoint, the remainder of this specification will be directed ~o the use of such material.
Thus, the inner member 30 is preferably formed of crimped filamentary cellulose acetate members bonded together at their contact points to form a smoke-permeable element defining a tortuous path for passage of smoke therethrough.
- Filtering material of this nature is well known, as are techniques for producing same.
As will be seen from Figures i and 4, integral cir-cumferentially continuous peripheral portions of the outer surface of the inner member 30 are juxtaposed to portion of the inner surface of the outer member 28 to a-t least substantially preclude axial passage of smoke across the area therebetween.
Such an arrangement is shown at both ends of the inner and outer members in the embodiment of Figure 1, since the grooves to be discussed in more detail hereinafter terminate short of the ends of this element. However, it is to be understood tha-t the instant invention covers an arrangement wherein the grooves to be discus~ed further hereinafter extend to the end of the filter element opposite from the inner cavity, also to be discussed in more detail hereinafter.
According to a basic feature of this invention, limited portions of the remaining outer surface of the inner ; member 30, excluding the continuous peripheral portions 32, 34, :, .
: - , . . .~ . .
.. . ..
73S~
are spaced from the inner surface of the oute~ member 28 to define outer cavity means therebetween which offer less resistance to passage of smoke ~han the filtering material of the inner member, as well as the areas at which the outer surface of the inner member and the inner surface of the outer member are juxta-posed. In the embodiment of Figures 1, 3 and 4, -these limited portions are shown as axially elongated, circumferentially spaced, grooves 36 which together define the outer cavity means of the inner member 30.
It should be understood that these grooves have been exaggerated in the drawings for illustrative clarity and that they ar~, in fact, preferably substantially smaller in circum-ferential extent than the illustrated embodiments. Moreover, although 8 grooves have been shown, any number of external grooves may be utilized so long as the remaining requirements of this invention are maintained. In fact, a preferred embodiment of this invention utilizes 16 such grooves as will be described subsequently.
A critical feature of this invention resides in the fact that the major portion of the total outer surface of the inner member 30, includin~ the peripheral portions 32, 34, is ; ~uxtaposed to the inner surface of the outer member 28 to provide substant.ially uniform support to the outer member 28 by the inner member 30 throughout its length. Thus, the outer cavity means must be limited in nature such that the remaining outer surface of the inner member 30 is substantially smooth and continuous.
~` For example, the outer cavity means can comprise from about 5 to no more than 50 percent of the total outer surface of the inner member 30 without departing from the .instant inventive concepts, with a proportion of 20 to 30 percent being considered optimum.
By thus providing substantially uniform continuous support for the outer member 28 over its entire length it is _ 9 _ . ... . . . .
~ 3~
possible to use a lighter weight plug wrap for the outer member 28 than is required when substantially greater portions of the inner member are spaced from the outer member as, for example, in a filter of the type shown in U~S. Patent No. 3,533,416.
Moreover, this subs-tantially uniform support precludes the need for an internal glue line between the inner and outer members as has been necessary with prior art techniques. Additionally, by avoiding significant crimping of the inner member according to the instant invention, substantially more of the filtering 10 material is available -to perform its primary function, that IS, removal of undesirable constituents from the tobacco smoke passing therethrough. Yet, the provision of the limited outer cavity means enables the passage of smoke to be directed uniformly over all of the filtering material of the inner member, thereby further improving filtration efficiency.
Referring again to Figure 1, integral first portions of the inner member 30 extend transversely across the full dia-meter of thP inner member 30 in the form of an uncrimped plug 38 of filtering material defining a tortuous path for smoke therethrough. Integral second portions 40 of the inner member 30 which are axially spaced from the first portions 38, define an area extending across the interior oE the inner member 30 which offers less resistance to passage of smoke than the filtering material, as well as the areas at which the outer surface of the inner member and the inner surface of the outer member are juxtaposed, in the embodiment shown this second area being merely the opening at the end of the inner cavity means 42 between the first and second portions 38, 40, respectively. This inner cavity means 42 offers less resistance to passage of smoke than the filtering material of the inner member 30.
Thus, the path of travel of smolce from the tobacco rod 22 is through the plug section 38 into the grooves 36 which ~7;3 5i~
distribute the smoke uniformly over the surface of the inner member for passage through the filtering material into the inner cavity means 42 to the mouth of the user.
Of course, it is possible to reverse the filter element 24 in the filtered cigarette 20 so that the area 40 ls juxtaposed to the tobacco section 22, rather than the area 38.
In Figure 3 a continuous rod 50 made up of a multiplic-ity of integrally connected filter elements of the type shown at 24 in Figure 1 will be seen. This rod is severed transversely along the lines 52, 54, to produce individual filter elements such as shown at 24. Of course, the rod could be severed at other locations to produce filter elements of multiple length.
Moreover, it is common practice to initially produce double filters which are then secured to two tobacco sections by a common tipping overwrap following which individual filtered cigarettes are formed by severing the double filter at its midpoint.
Reference is now made particularly to Figure 2 for the overall method and means utilized in producing filter elements in accordance with this invention. Basically, this overall technique is similar in many respects to the techniques shown and described in detail in U.S. Patent No. 3,637,44, referred to previously, while other modifications are similar to specific ; elements shown in detail in U.S. Patent No. 3,811,451, also referred to previously. According to preferred embodiments of this invention, the filtering material utilized in production of filter elements is a continuous filamentary tow, dasignated ` generally by the reference numeral 60 which includes a multi-plic1ty oE bondable fibrous members activated by contact with a hot ~luid such as steam. The filtering material 60 is continuous-ly passed into and through an elongated bonding zone 62 which may comprise a conventional stuffer jet and steam head similar .
.
.,, ~735~, in nature to those shown in various o~ the above-mentioned prior art patents. Specifically, the tow is contacted with steam entering through conduit 64, shown in detail in Figure 10, and is then distributed through a multiplicity of circumferentially spaced passageways ~6 into the bonding zone as the filtering material 60 passes therethrough. A mandrel 68 is positioned generally axially o~ the bonding zone to define an annular space through which the filtering material ~0 must pass and the mandrel ~8 is reciprocated between the full line position and the dotted line position in timed relationship to the passage of the filter-ing material, the dotted position being at least as far forward in the path of travel of the filtering material as the point at which the filtering material is contacted by the bond activating agent, namely steam, to thereby produce a smoke-permeable annular wall of bonded fibrous members as the filtering material passes this point, with the full line position of the mandrel 68 being sufficiently rearwardly of the point in the path of travel of the filtering material at which the steam contacts same to permit a portion of the filtering material to extend transversely completely across the bonding zone before reaching this poin~, thereby producing a smoke-permeable plug section of bonded fibrous members as the filtering material passes this point. The annular wall and the plug sections are integral with each other to provide the rod 50 with intermittent inner cavity means 42 totally en-closed and surrounded by the annular wall and by plug sections forwardly and rearwardly thereof, as will be seen particularly in Figure 3.
i ` Following the steam treatment, the rod is cooled at 70, the garniture 72 providing a continuous pulling mechanism drawing the rod through the initial processing stages.
The outer cavity means 36 may be fo~med in the rod 50 by a variety of techniques and devices, one of which is shown .
: . ., , : . .
,, , . . , . ~
.. , ~ , . .
~l735~
broadly at 74 in Figure 2 and illustrated in detail in Figures 5 and 6. Specifically, this mechanical ironing device 74 includes a steam head portion 76 wherein steam enters through conduit 78 and is distributed by circumferentially spaced passage-ways 80 to contact and soften the outer surface o~ the rod 50 as it passes therethrough. The remaining portion 82 of the device 74 comprises forming means for intermittently projecting a ~ plurality of radially extending, circumferen~ially spaced, pins 84 into contact with the rod 50 as it is continuously moved past said pins by the additional garniture means 86. In this embodi-ment, a guide member 88 forms an axial bore 90 for passage of the rod 50 and supports the pins 84 in radial extending passage-ways which each have an enlarged section slidingly carrying cam followers 92 each of which carries one of the pins 84. The cam followers 92 are biased outwardly by spring means 94 to engage a cam surface of a cam ring 96, which cam surface includes first portions 98 for pressing the pins 84 radially inwardly to project the ends thereof into the bore 90 and alternating second portions 100 which permit the pins 84 to move radially outwardly so that their ends are withdrawn from the bore 90. Any conventional means, such as the gear teeth 102, may be provided for rotating the cam ring 96 as shown by the arrow in Figure 6, so that the first and second portions 98, 100 alternately engage the cam i followers ~2.
Of course, the cam surface is designed so as to form the grooves 36 over only a limited portion of the outer surface I of the rod as it passes through the device 74. For example, a presently preferred embodiment utilizes 16 equally spaced pins each having a diameter of 1/32 inch which, due to the inherent resiliency of the material of the inner member actually produce grooves having a circumferential extend or width of only about 0.02Q inch~ The groove can have any radial extent or depth, ., .
. .
~`9~35~
short of engaging the inner cavity ~2, although shallow grooves e.g., approximately 0.020 inch, are fully satisfactory. The axial extent or length of the grooves in the preferred embodiment is approximately 2/3 of the total axial extent of the inner member, terminating equidistant Erom each end of the inner mernber.
As an example cf how limited the outer cavity may be in order to provide a substantially smooth outer surface while still assisting in distribution of the smoke over the entire filtering material, the grooves may even be formed from a plurality of circumferentially spaced radially extending, razor blades. Thus, only a limited break in the sealed peripheral areas is necessary to improve overall use of the filtration material.
Turning again to Figure 2, once the outer cavity means 36 have been formed, the rod 50 is overwrapped in the garniture means 86 with a conventional plug wrap, a source of which is shown at 104.
Finally, the rod is severed transversely at selected locations in a cutting means shown schematically a~ 106.
An alternate technique for defining the grooves 36 is by intermittently projecting jets of steam into contact with the outer sur~ace of the rod 50 as it is moved past such jets. A
mechanism for forming the grooves 36 in this manner is seen particularly in Figures 7-9, this arrangement being similar to the mechanism shown in Figures 5 and 6, like parts being designat-ed by the same re~erence numeral followed by the suffix "a" to facilitate an understanding of this device. ~he guide means 88a includes portions defining a plurality of radially extending, circumferentially spaced, passageways 110 communicating with the bore 90a. Steam is fed through a conduit 112 to the passageways 110, with the cam followers 92a carrying valve means 114 at their radially inward ends. The valve means comprise vents 116 which in thelr radially inward position communicate with the conduit .. . . . .. . . . ... . . . .
~'73S:~L
112 and vent the steam to the atmosphere whereas, in the radially outward position of the valve means 114 shown in Figure 9, the conduit 112 is in communication with the passageways 110 so that jets of steam are intermittently projected into the bore 90a.
The remainder of this device func-tions in a manner similar to the device of Figures 5 and 6.
In addi-tion to either of the techniques shown pre-viously for forming the external grooves 36, crimping wheels similar to those shown in Figures 10-13 of U.S. Paten~ No.
3,637,447 may be used. A portion of one such crimping wheel is shown in Figure 16 at 120 and will be seen to comprise crimping portions 122 having raised projections 124 corresponding to the grooves 36 with intermittent recessed portion 126 which function to form the uncrimped peripheral portions 32, 3~ of the individual filter elements. A multiplicity of such crimping wheels may be used in combination as shown in Figure 17 to simultaneously form all of the grooves around the peripheral surface of the rod 50 as they engage the rod~
A modified form o~ ~iltered cigarette and filter rod according to the instant inventive concepts is shwon in Figures 11-13. Except for the external cavity means, this embodiment is substantially identical with the embodiment of Figures 1, 3 and ~ and, therefore, similar parts have been designated by the same reference numeral followed by a suffix "b". In this embodiment ` the outer cavity means 36b is defined by a plurality of inter-~connecting axially and circum~erentiall~ extending outer cavities defining a knurled-like outer sur~ace shown in detail in Figure ~3. Of course, it is important that the knurled-like portion be so defined that a major part of the outer surface of the inner member 30b be in contact with, and support, the inner surface of the outer member 28b.
This knurled-like surface may be formed in any con-,~ ' , . . . ... .. .
:, .. ~ . , . : .
'3~i~
ventional manner such as, by the use of crimping wheels, a portion of one of which is illustratively shown at 130 in Figure 18.
Alternatively, vacuum means may be utilized to pull portions of the outer surface of the inner member 30b radially o~t~ardly leaving the remaining surface portions to form the outer cavity in a knurled-like pattern.
Similarly, a further embodiment of the instant inventive concept is shown in Figures 1~ and 15, wherein parts similar to those of the embodiment of Figures 1, 3 and 4 are designated by the same reference numeral followed hy a suffix "c". It will be seen from Figures 14 and 15 that the ou-ter cavity means 36c are in the form of a continuous helical groove.
This helical groove can be formed in any conventional ~; manner, such as, for example, by a multiplicity of crimping :~ wheels, a portion of one of which is shown illustratively at 140 in Figure 19.
Other patterns for the outer cavity means will be readily recognized by those with ordinary skill in the art, as will techniques and devices for producing same.
Although the outer cavity means can be formed by a crimping technique, it will be seen that crimping of this nature is not as extensive as with the production of prior art Eilter devices such as those shown in the various above-identiEied , patents. With a substantial crimping of the filter rod, the rod ; is frequently distorted requiring the use of a relatively heavy-weight plug wrap to force it back into its round shape. The use of such heavier material, of course, increases the cost. Moreover, ~ substantiaI crimping of the filter elements renders the crimped i portions relatively useless as a filtering medium, thereby reducing the overall efficiency of the final product.
The following data compares certain characteristics oE products made according to the instant inventive concepts . ~' -~7935~
designated as "I" and "II" with produc-ts according -to prior art techniques, a single filter element of the type shown, for example in U.S. Patent No. 3,637,447 being designa-ted at "III" and a double filter element of the ~ype shown in U.S. Patent No.
3,805,801 being designated as "IV" in the table below.
Percent Type Weight Pressure Drop Retention I 11.5 gms 2.7" 71.8 II 11.7 gms 2.8" 70.8 III 16.5 gms 2.8" 69 IV 13~ gms 2.8" 65 It will be seen from the above that filter elements prepared according to the instant inventive concepts compare ; favorably with the prior art filters with respect to pressure drop, while pxoviding at least as good as, and frequently better, ~iltration efficiency with less material. Other commercially significant properties such as hardness, taste and the like also compare favorably with prior art filter elements.
Although the outer member 28 in the various embodiments described hereinabove has been the plug wrap and the inner member 30 has been formed entirely of a filtration material such as cellulose acetate tow or the like, a further possible modification within the instant inventive concepts utilizes the plug wrap as a part of the filtration material. Reference is made to Figure 20 wherein such an embodiment is shown with parts similar to previous embodiments bearing the same reference numeral followed by a suffix "d".
Porous or smoke-permeable plug wraps are well known and are commercially available under various trade designations, e.g., Ecusta Ref. #2961~ or Schweitzer Ref. #638-63-1. When using a material of this type it is possible to overwrap the cellulose acetate rod with porous plug wrap prior to forming the ;
7~
outer cavity means. Thus, if desired, in a sys-tem such as the one shown in Figure 2, the porous plug wrap may be secured about the cellulose ace-tate rod in the garniture means 72 as shown in dotted lines at 104' rather than in the garniture means 86 as shown in full lines at 104. Then, outer cavity means such as a plurality of circumferentially spaced, axially extending grooves 36d may be formed such as by crimping wheels or the like in the outer surface of this composite inner member, that is, the cellulose acetate rod 24d covered wi-th porous plug wrap 28d.
Preferably such grooves would extend completely over the plug sections 34d of the cellulose acetate rod and terminate short of the midsections of the inner cavity means 42d. With an "inner member" of this type, the tipping overwrap 26d used -to join the filter section of the tobacco section functions as the "outer member" of the filter element 20d. Thus, the use of the terms "inner member" and "outer member" herein and in the appended , claims is to be understood as being broad enough to include an ; arrangement wherein the "inner member" is a composite element including a porous plug wrap and the "outer member" is the tipping 20 overwrap. With such a construction the smoke passes through the~
inner and outer cavity means, as well as the porous plug wrap and the cellulose acetate filtration material of the inner member affording even further filtration resulting from the presence of the plug wrap in the smoke path.
It will now be seen that there is herein provided a smoke fllter and method and means for manufacturing same which satisfies the various objectives set forth previously, and which provide significant advantages of a commercial nature. While this invention has been described with reference to presently : : ..
~` 30 preferred exemplary embodiments thereof, it should be clearly .
, ~ understood that the invention is not limited thereto, but may be variously practiced within the scope of the following claims.
;
'735~
This application is a divisional application from application No. 254,767 filed on June 14, 1976.
. .
:
, ' '~
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for making smoke filter means comprising, a. a source of a bondable filtering material including a multiplicity of fibrous members, b, means defining an elongated bonding zone, c. means for continuously feeding said filtering material into and through said bonding zone, d. means for feeding a bonding activating agent into said bonding zone and into contact with said filtering material at a point inter-mediate the path of travel of said filtering material through said bonding zone to bond said fibrous members of said filtering material to each other at spaced contact points, thereby forming an elongated, smoke-permeable, rod defining a tortuous path for passage of smoke therethrough, e. elongated mandrel means having a forward end portion axially positioned within said means defining said bonding zone to define an annular space through which said filtering material must pass, f. means for recipro-cating said mandrel means within said bonding zone in timed relationship to the passage of said filtering material through said bonding zone between a first position wherein said forward end portion extends at least as far forwardly in the path of travel of said filtering material as the point at which said filtering material is contacted by said bond activating agent, to thereby produce a smoke-permeable annular wall of bonded fibrous members as said filtering material passes said point, and a second position wherein said forward end portion extends suffic-iently rearwardly of said point in the path of travel of said filtering material to permit a portion of said filtering material to extend transversely completely across said bonding zone before reaching said point, to thereby produce a smoke-permeable plug section of bonded fibrous members as said filtering material passes said point, said annular wall and said plug sections being integral with each other, whereby said rod is provided with intermittent inner cavities totally enclosed and surrounded by said annular wall and by plug sections forwardly and rearwardly thereof, g. forming means for forming outer cavity means on the exterior surface of said rod, said forming means producing outer cavity means axially spaced from each other at a position on either side of a transverse axis intermediate each inner cavity means with the surface area of said outer cavity means forming a minor portion of the total exterior surface of said rod, h.
means for overwrapping said rod with an overwrapping material so as to juxtapose portions of the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding passage of smoke thereacross, and i. severing means for transversely severing said overwrapped rod at selected locations to form filter elements.
means for overwrapping said rod with an overwrapping material so as to juxtapose portions of the inner surface of said overwrapping material with peripheral portions of the exterior surface of said rod to form sealed areas precluding passage of smoke thereacross, and i. severing means for transversely severing said overwrapped rod at selected locations to form filter elements.
2. An apparatus according to claim 1 wherein said forming means comprises means for softening the exterior surface of said rod, and means for intermittently projecting a plurality of radially extending, circumferentially spaced, pins into contact with said rod as said rod is continuously moved past said pins.
3. An apparatus according to claim 1 wherein said means for intermittently projecting said pins includes guide means defining an axial bore for passage of said rod therethrough, a plurality of radially extending, circumferentially spaced, pins about said bore, each of said pins being carried by a cam follower, cam means engaging each of said cam followers and having a cam surface including first portions for pressing said pins radially inwardly to project the ends thereof into said bore and alternating second portions permitting said pins to move radially outwardly so that their ends are withdrawn from said bore, spring means biasing each of said cam followers into contact with said cam surface, and means for rotating said cam means so that said first and second portions of said cam surface alternatingly engage said cam followers.
4. An apparatus according to claim 1 wherein said forming means comprises means for intermittently projecting radially extending jets of steam into contact with said rod as said rod is continuously moved past said jets.
5. An apparatus according to claim 4 wherein said means for intermittently projecting said jets of steam includes guide means defining an axial bore for passage of said rod there-through, a plurality of radially extending, circumferentially spaced passageways defined in said guide means, said passageways communicating with said bore, a source of steam, conduit means connecting said source of steam with said passageway, valve means interposed in said conduit means, and means for inter-mittently opening and closing said valve means for alternately direct steam into and away from said passageways.
6. An apparatus according to claim 5 wherein said valve means comprise valve members each having a cam follower at one end and each defining a vent means for directing said steam away from said passageways, cam means engaging each of said cam followers of said valve means and having a cam surface including first portions for moving said valve means radially inwardly to communicate said vent means with said conduit means and directing said steam away from said passageways, and alternating second portions permitting said valve means to move radially outwardly so that said conduit means communicate with said passageways, spring means for biasing each of said cam followers of said valve means into contact with said cam surface, and means for rotating said cam means so that said first and second portions of said cam surface alternatingly engage said cam followers.
7. An apparatus according to claim 1 wherein said forming means comprise crimping means.
8. An apparatus according to claim 1 further including means for covering said rod with a smoke-permeable plug wrap interposed between said bonding zone and said forming means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/627,858 US4022221A (en) | 1975-10-31 | 1975-10-31 | Tobacco smoke filter |
| CA254,767A CA1049877A (en) | 1975-10-31 | 1976-06-14 | Tobacco smoke filter (itf grooved) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047351A true CA1047351A (en) | 1979-01-30 |
Family
ID=25668307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA306,036A Expired CA1047351A (en) | 1975-10-31 | 1978-06-22 | Tobacco smoke filter (itf grooved) |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047351A (en) |
-
1978
- 1978-06-22 CA CA306,036A patent/CA1047351A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4075936A (en) | Method and apparatus for making tobacco smoke filter | |
| US4064791A (en) | Method and apparatus for making tobacco smoke filter | |
| US4022222A (en) | Tobacco smoke filter | |
| US3637447A (en) | Method of making filter means by crimping and overwrapping a tubular element | |
| US3847064A (en) | Tobacco smoke filter | |
| US4508525A (en) | Method and apparatus for producing tobacco smoke filter having improved tar/carbon monoxide ratio | |
| US4357950A (en) | Tobacco smoke filter having improved tar/carbon monoxide ratio | |
| US3648711A (en) | Tobacco smoke filter | |
| US4046063A (en) | Method and apparatus for making tobacco smoke filter | |
| US4488563A (en) | Filter plug | |
| US4637409A (en) | Tobacco smoke filter and method and apparatus for making same | |
| US4291711A (en) | Tobacco smoke filter providing tobacco flavor enrichment, and method for producing same | |
| CA1096737A (en) | Smoke filters | |
| US3811451A (en) | Tobacco smoke filter | |
| JP6462212B2 (en) | Cigarette smoking filter | |
| US3826177A (en) | Apparatus for making filter means | |
| US4784632A (en) | Tobacco smoke filter and method and apparatus for making same | |
| US3703429A (en) | Apparatus for making filter means | |
| US3774508A (en) | Apparatus for making filter means | |
| US4059043A (en) | Method and apparatus for making tobacco smoke filters | |
| US3994306A (en) | Tobacco smoke filter | |
| AU629320B2 (en) | Uniform tar delivery profile filter | |
| GB2103065A (en) | Ventilated cigarette filter | |
| CA1047351A (en) | Tobacco smoke filter (itf grooved) | |
| GB2105566A (en) | Tobacco smoke filtering device |