U.S. patent number 3,637,447 [Application Number 05/045,109] was granted by the patent office on 1972-01-25 for method of making filter means by crimping and overwrapping a tubular element.
This patent grant is currently assigned to American Filtrona Corporation. Invention is credited to Richard M. Berger, Elwin W. Brooks.
United States Patent |
3,637,447 |
Berger , et al. |
January 25, 1972 |
METHOD OF MAKING FILTER MEANS BY CRIMPING AND OVERWRAPPING A
TUBULAR ELEMENT
Abstract
A method and apparatus for making filter means of a type which
is constructed to provide elongated, high-surface area, cavities
defined on opposite sides of a relatively thin wall formed of
filtering material with only the ends of the filter means
contacting an overwrapped outer tube thereby presenting maximum
available surface area of the material from which the products are
formed to the smoke for filtration is disclosed. A tow of a
suitable filtering material is passed through an air nozzle
containing a mandrel centered therein, the tow thereby achieving a
uniformly random, but tubular, configuration and then through a
steam-curing station followed by an air-curing station. The formed
rod is then again steam cured and passes to a crimping device which
imparts a particular configuration thereto. The crimped rod is then
again air cured, wrapped, and cut. In another embodiment, an
addition material may be added by means either of a printing
applicator device or a pulsating nozzle device.
Inventors: |
Berger; Richard M. (Richmond,
VA), Brooks; Elwin W. (Mechanicsville, VA) |
Assignee: |
American Filtrona Corporation
(Richmond, VA)
|
Family
ID: |
21936042 |
Appl.
No.: |
05/045,109 |
Filed: |
June 10, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
727477 |
May 8, 1968 |
3533416 |
|
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|
820355 |
Apr 30, 1969 |
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Current U.S.
Class: |
156/180; 156/198;
264/137; 264/168; 493/44; 156/176; 156/441; 493/43; 493/45 |
Current CPC
Class: |
A24D
3/0283 (20130101); Y10T 156/1005 (20150115) |
Current International
Class: |
A24D
3/00 (20060101); A24D 3/02 (20060101); B29h
009/02 () |
Field of
Search: |
;93/1C
;131/10.5,10.7,10.9,10.3 ;156/166,180,198,205,441,176
;264/147,150,137,168 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Quarforth; Carl D.
Assistant Examiner: Gaither; Roger S.
Parent Case Text
This application is a continuation-in-part of copending application
Ser. No. 727,477, filed May 8, 1968, now U.S. Pat. No. 3,533,416
and of copending application Ser. No. 820,355, filed Apr. 30, 1969,
which in turn is a continuation-in-part of the aforementioned
application Ser. No. 727,477.
Claims
We claim:
1. A method of making a filter means comprising
a. providing a bondable continuous filamentary tow-filtering
material, forming said filtering material by passing said filtering
material through an elongated annular zone and bonding said
filtering material into an elongated, hollow, inner element;
b. crimping said inner element at axially spaced locations to form
closed crimped portions extending across the interior of said inner
element at said spaced locations with uncrimped portions
therebetween;
c. overwrapping said inner element with an axially elongated hollow
outer element, portions of the inner surface of which are
juxtaposed to peripheral portions of said uncrimped portions of
said inner element in a manner to at least substantially preclude
axial passage of smoke across the area between said peripheral
portions of said inner element and said portions of the inner
surface of said outer element, the major portion of the outer
surface of said inner element being spaced from the inner surface
of said outer element; and
d. cutting said overwrapped inner element to provide segments
having at least part of one crimped portion of said inner element
and at least part of one uncrimped portion of said inner
element.
2. The method of claim 1 wherein said segments defined in step (d)
include parts of a plurality of crimped portions of said inner
element and parts of a plurality of uncrimped portions of said
inner element, including the step of further subdividing said
segments to provide filter elements having an inner member defined
by part of only one crimped portion of said inner element and part
of only one uncrimped portion of said inner element, and an outer
member formed by part of said outer element.
3. The method of claim 1, wherein said filtering material is formed
into an axially elongated, hollow, inner element as defined in step
(a) by passing said filtering material through air nozzle means
having elongated mandrel means axially disposed therein, through
steam jet means having mandrel extending thereinto, and then
through air jet means.
4. The method of claim 1, wherein said inner element is crimped as
defined in step (b) by passing the same through steam jet means,
through heated crimping means comprising crimping wheels, and then
through air jet means.
5. The method of claim 1 further including the step of applying a
second filtering material to said axially elongated, hollow, inner
element.
Description
This invention relates to the production of filter means and
particularly to the production of tobacco smoke filter elements.
More specifically, this invention relates to methods and apparatus
for the production of such filter means.
Various prior art techniques are known for making filters for use
in connection with cigarettes, and the like, although the resulting
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 undesirable constituents from tobacco
smoke. Filtration efficiency is ordinarily measured in terms of the
percentage of total particulate 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 a cigarette filter means, it has been necessary, with prior art
filter devices, to compromise the filtration efficiency in order to
provide this filter with other properties, such as pressure drop,
taste, hardness, appearance and cost, which are important from the
standpoint of acceptability. For example, the most commonly
utilized cellulose acetate filter means has a relatively
low-filtration efficiency since increased 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 standpoint. While various suggestions have been made for
the production of filter means which have improved filtering
properties, such prior art developments have not become commercial
either because the resultant filter means have been found to have
objectionable "taste" characteristics whereby cigarettes provided
with such filtering means fail to satisfy a large 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.
In any event, it is well known in the industry that there is no
filter means presently on the market which provides relatively
high-filtration efficiency, on the order of 60-95 percent (TPM),
without suffering from undesirably high manufacturing costs, poor
taste, high-pressure drop or other such commercially unacceptable
characteristics. The need and desirability of providing such a
filter means is believed to be readily apparent, and the invention
described and claimed in the aforementioned copending application
Ser. No. 727,477, is directed to this need. That invention provides
a filter means for use with a cigarette, or the like, having
exceptionally high-filtration efficiency, in many embodiments
removing as much as 95 percent of the total particulate matter,
while having an acceptable pressure drop, as well as satisfactory
"taste", hardness and appearance. Further, there is described in
the aforesaid copending application Ser. No. 727,477 various
techniques for the production of filter means of the type described
utilizing inexpensive materials in relatively small quantities, as
well as simple and efficient procedures whereby such filter means
can be manufactured on a mass production basis at a cost which is
acceptable to the industry. Accordingly, the present invention
provides processing equipment and techniques which permit high
speed, continuous production of integral products of this nature
without the use for handling special baffles or other extraneous
elements which tend to slow down production rates and increase
rejects due to the difficulty in manipulating such small articles
in a commercial operation.
A particular means for forming filter elements of the type
described is described on pages 13 through 15 of the aforementioned
copending application Ser. No. 727,477 and such disclosure is
embodied herein in its entirety by reference. The aforesaid means,
described in relatively general terms in the aforementioned
copending application, is the basic means utilized for
manufacturing the novel filter of that invention. The present
invention, however, is concerned with a more efficient improved
apparatus for achieving the result, namely, the production of that
novel filter.
Accordingly, it is a primary object of the present invention to
provide an apparatus for making filters of the type described which
operates at high speed.
It is another primary object of the present invention to provide an
apparatus for the high speed, continuous production of filters of
the type described without the need for handling special baffles,
or other extraneous elements.
It is a further object of the present invention to provide an
apparatus for making filters of the type described using a large
variety of filtering materials.
Consistent with the foregoing objects, it is yet another object of
the present invention to provide an apparatus for the manufacture
of filter means which are self-sustaining and self-centering, with
an integral construction, and with a maximum available surface area
being presented for filtration of smoke passing therethrough.
It is still another object of the present invention to provide an
improved filter having high-filtration efficiency while having an
acceptable pressure drop.
It is yet another object of the present invention to provide an
improved filter manufactured by the method and apparatus
described.
Other objects of the present invention will either be set forth
specifically hereinafter or will be obvious from the following
detailed description. Such description makes reference to the
annexed drawings, wherein:
FIG. 1 is a schematic view of one embodiment of a method and means
for making filter elements of the type described;
FIG. 2 is an exploded vertical cross-sectional view of means for
forming a band of filtering material into an axially elongated,
hollow, filtering element;
FIG. 3 is a side view of a mandrel used in conjunction with the
means of FIG. 2;
FIG. 4 is a perspective view of the mandrel support utilized in
conjunction with the mandrel of FIG. 3 and the means of FIG. 2;
FIG. 5 is a perspective view of the air nozzle and mandrel assembly
containing the elements depicted in FIGS. 2 through 4;
FIG. 6 is an enlarged fragmentary perspective view of a portion of
a filtered cigarette incorporating a filter element manufactured
according to the instant inventive concepts, parts being broken
away and in section for illustrative clarity, and modifications of
this embodiment of a filter means according hereto being shown in
dotted lines;
FIGS 7, 8 and 9 are enlarged fragmentary perspective views of other
embodiments of the filter of FIG. 6;
FIG. 10 is a partially broken away vertical elevational view of the
crimping assembly utilized in the apparatus of the present
invention and embodying the crimping wheel of FIG. 11;
FIG. 11 is a vertical elevational view of a crimping wheel used in
the apparatus of the present invention;
FIG. 12 is a partial edge view of the crimping wheel of FIG.
11;
FIG. 13 is a vertical sectional view, taken on line 13--13 of FIG.
12;
FIG. 14 is a side view, partially broken away, of a filter rod made
in the apparatus of the present invention;
FIG. 15 is a transverse cross-sectional view, taken along line
15--15 of FIG. 14;
FIG. 16 is a transverse cross-sectional view, taken along line
16--16 of FIG. 14;
FIG. 17 is a fragmentary schematic view of another embodiment of
the method and means of the present invention;
FIG. 18 is a fragmentary schematic view of still another embodiment
of the method and means of the present invention; and
FIG. 19 is a fragmentary schematic view of yet another embodiment
of the method and means of the present invention.
Like reference characters refer to like parts throughout the
several views of the drawings.
Referring now to the drawings, and more particularly to FIG. 1, a
method and means for forming filter elements of the type described
is schematically designated by the reference numeral 10. It should
be noted at the outset that the various stations of the apparatus
are arranged in a single plane, but for ease of illustration, the
schematic presentation is shown in two segments. Filtering material
in band form is designated at 12. This filtering material in band
form is coming from a bale and band-forming apparatus conventional
in the trade which are not shown. The filtering material 12 can
comprise any suitable substance, such as, for example, cellulose
acetate fibers in the form of a continuous filamentary tow. For
certain uses and to achieve certain filtering and/or absorbing
and/or liquid-holding properties, the cellulose acetate fibers may
be mixed with other materials, such as cellulose, viscose, cotton,
cellulose acetate-butyrate, cellulose propionate, activated carbon,
asbestos, glass fibers, metal fibers, wood fibers, and the like.
The material is preferably opened, crimped, continuous filamentary
cellulose acetate tow having about 9 percent glycerin triacetate as
a plasticizer in fine droplets distributed upon its surface. Any
suitable plasticizer may be used, such materials being well known
in the art.
The term "continuous filamentary tow", as used in this
specification and the appended claims, is intended to define a
material such as that which results when filaments extruded from a
plurality of spinnerets are brought together and combined to form a
continuous body of fibers randomly oriented primarily in a
longitudinal direction. In such a tow, the filaments are generally
longitudinally aligned in substantially parallel orientation, but
include crimped portions which may form short sections running more
or less at random in nonparallel diverging and converging
directions.
Continuous filamentary tows of plasticized cellulose acetate fibers
as well as various other plastic materials, such as polyethylene,
polyropylene, nylon, and the like, have been used heretofore in the
manufacture of smoke filters for cigarettes, cigars, an the like.
Although the process of this invention is applicable to the various
filamentary materials of this type, since plasticized cellulose
acetate is the most common plastic used in the manufacture of
cigarette filters, the specification hereof will be generally set
forth in terms of this material. However, it is to be understood
that the instant inventive concepts are not to be limited to this
preferred embodiment.
Generally, the fibers of a cellulose acetate tow merging from the
spinneret are bunched together to form a "raw tow" which is
collected into a bale for subsequent processing. Such processing
usually involves, in addition to unwinding of the "raw tow",
spreading apart of the fibers to provide a relatively thin layer of
the same, tensioning of the fibers to render the crimp of uniform
character, and impregnating the fibrous layer with plasticizer to
bind adjacent fibers together.
The tow of filtering material 12 in band form is fed into a stuffer
jet, or air nozzle, 14. The construction of the air nozzle 14 is
shown in FIGS. 2 through 5. The air nozzle 14 comprises an outer
member 16, an inner member 18, a mandrel 20, a mandrel support 22,
and a retaining ring 24. The air nozzle 14 is generally shaped as a
truncated cone, thereby having a greater cross section at the
entrance end 26 than at the exit end 28. The inner member 18 is
suitably connected to the outer member 16 as, for example, by the
threaded portions 30 and 32. By use of threaded portions 30 and 32,
the alignment of inner member 18 in outer member 16 can be adjusted
for a purpose which will become apparent. The inner member 18 is
also threaded at 34 and mandrel support 22 is threaded at 36.
Retaining ring 24 contains threaded portion 38 to cooperate with
the threads 34 and 36 thereby holding mandrel support 22 in
position. The mandrel support 22 has an inner portion 42 in annular
relation with the outer portion thereof 44. Inner portion 42 of
mandrel support 22 is supported by support portion 46. Inner
portion 42 is suitably threaded at 48 to receive threaded portion
40 of mandrel 20.
Outer member 16 has a connection 50 for compressed air. Wall 52 of
outer member 16 and wall 54 of inner member 18 are of such a
relationship that, when assembled, annular space 56, as best seen
in FIG. 1, is created. The purpose of annular chamber 56 will
become apparent from the following description.
Returning now to FIG. 1, it will be seen that the elongated band of
filtering material 12 enters the rearward end 26 of air nozzle 14
passing through the mandrel support 22 and generally being forced,
in a random manner, around inner portion 42 of the mandrel support
22. The tow at this point is generally a hollow tubular element
which continues around mandrel 20 to the forward end 28 of air
nozzle 14. As the tow emerges from the forward end 28 of air nozzle
14, it is mixed with air supplied through fitting 50 and passing
through chamber 56 to the exit, or forward, end 28 of air nozzle
14. Adjustment of inner member 18 in outer member 16 by means of
threaded portions 30 and 32 creates a venturilike opening at the
exit end 28 of air nozzle 14, between forward end 19 of inner
member 18 and forward end portion 21 of outer member 16. This
opening could range in size from fully closed to about
three-fourths inch, but the practical limits of use, in order to
obtain the desired venturi effect at customary air pressures, are
from about 0.005 to about 0.050 inch. The tow emerging from the
exit end 28 of air nozzle 14, mixed with air, "explodes" or blooms
into a uniformly random fluffy mass 58 before passing into the
first curing station 60. Mandrel 20 passes through air nozzle 14
and into the first curing station 60, extending through and
slightly beyond first curing station 60. It should be noted that at
this point, that the upstanding portion 46 of mandrel support 22
does not affect the ultimate tubular shape imparted to the tow
since the tow comprises a plurality of plasticized random filaments
which separate when going around that obstruction but then come
together and, in passing through the air nozzle 14, assume the
proper cross section.
The first curing station 60 is a heating and shaping apparatus,
such as that disclosed in U.S. Pat. No. 3,095,343, issued on June
25, 1963, to Richard M. Berger. Since this apparatus is now known
in the art, it need only be described herein in general terms,
reference being had to the aforementioned U.S. Pat. No. 3,095,343
for details of its construction.
The heating and shaping apparatus making up the first curing
station 60 is constructed in such a way that the moving tow which
is being formed into a generally rodlike formation is contacted
with steam as it passes through a die. The application of the steam
to the filamentary tow as it is gathered together appears to result
in softening of the tow fibers and the plasticizer carried thereon,
and definitely has the effect of uniformly bonding the fibers of
the tow together as they are gathered. By passing the steam onto
the tow under pressure in a confined area at an angle to the
longitudinal axis, and in a direction opposite the direction of
movement of the tow, the steam is caused to pass through the tow,
between the fibers and past the fibers as they are being gathered
together. All of the filaments and all of the plasticizer are thus
at least substantially uniformly heated, and bonding is at least
substantially uniform throughout. Thus, the steam-treating
apparatus of the aforementioned U.S. Pat. No. 3,095,343 produces a
tubular, rodlike tow which proceeds to further treatment. Using the
apparatus of the present invention, however, with the forward end
of the mandrel 20 extending into and through the first curing
station 60, the tow is converted to an axially elongated, hollow
element 62.
The cured tow emerging from the first curing station is generally
self-sustaining in shape and in cured condition. The term "cured",
as used in the art, means a tow obtained from a process by which
the fibers of the tow are bonded to adjacent fibers after the
fibers have been gathered into a rodlike structure. The cured tow
62 then passes to a second curing station 64 wherein dry air is
passed on to the tow and through the tow to set the fiber
components and plasticizer components of the tow so that it has
complete dimensional stability without excess stiffness or fiber
fusion. Preferably, the air which is passed on to the tow at the
second curing station 64 is perfectly dry, has a temperature of
90.degree. F. or below, and is maintained under a pressure of
between 15 and 100 p.s.i.g. Moreover, for optimum results, the air
should be passed on to the tow countercurrent thereto and at an
angle of substantially 45.degree. to the longitudinal axis of the
tow, in much the same way as the steam contacts the tow in the
first curing station 60. A suitable apparatus for air-treating the
tow at the second curing station 64 is described in detail in the
aforementioned U.S. Pat. No. 3,095,343. The air inlet to the second
curing station 64 is indicated at 66, while the steam inlet to the
first curing station 60 is indicated at 68.
After leaving the second curing station 64, the tow 62 passes to a
pulling device generally designated by the numeral 70. The pulling
device 70 can be any conventional device for applying motive power
to the continuous filter rod 62 to move the same through the
apparatus. As depicted in FIG. 1, the pulling device could be a
conventional overwrap garniture with an endless belt 72 imparting a
pulling movement to the tow 62. The belt 72 is driven by drive
means schematically shown as 74.
Before continuing with the description of the method and apparatus
of the present invention, it would be helpful to become familiar
with the construction and advantages of the inventive filter means
described and claimed in the aforementioned copending applications
Ser. Nos: 727,477 and 820,355. To this end, attention is directed
to FIGS. 6 through 9, wherein a portion of a filter cigarette is
designated generally by the reference numeral 76 and comprises
basically a tobacco portion 78 and a filter portion 80. The tobacco
portion 78 comprises a rod of tobacco 82 overwrapped with paper, or
the like, 84, as usual. The filter portion 80, in the embodiment
shown in FIG. 6, comprises one form of filter element according to
the invention of the aforementioned copending applications Ser.
Nos: 727,477 and 820,355 designated generally by the reference
numeral 86 and secured in end-to-end relationship with one end of
the tobacco portion 78 as by a tipping overwrap 88.
The filter element 86 includes basically an axially elongated,
hollow, outer member 90 and an axially elongated, hollow, inner
member 92 disposed within the outer member 90. In this embodiment,
the outer member 90 is shown as a cylinder of ordinary "plug" wrap
as is conventionally used in the manufacture of filter elements for
cigarettes, although this member may be formed of plastic or other
materials, if desired.
The inner member 92 is that element with which we are primarily
concerned in the steps thus far described in the method and
apparatus of the instant invention. That is what may be called a
"tube" formed primarily of any one, or a combination of various,
filtering media, as already described hereinabove. One end portion
94 is cylindrical providing peripheral portions of the outer
surface of the inner member 92, limited in axial extent which are
juxtaposed to portions of the inner surface of the outer member 90
to at least substantially preclude axial passage of smoke across
the area therebetween. Any desired adhesive means (not shown) may
be included in this area to provide a smoketight seal, although the
outer member 90 may merely be overwrapped about the inner member 92
to provide a substantially smoketight seal in this area. The
important characteristic of this area is that smoke will pass
through portions of the filtering material of the inner member 92
as explained hereinafter before bypassing the inner member across
this area.
It will be noted that the major portions of the outer surface of
the inner member 92 are spaced from the inner surface of the outer
member 90 to define first elongated, high surface area, cavity
means 96 therebetween, this cavity means including the area
surrounding the end of the inner member 92 spaced from the sealed
area at 98 particularly if this end of the inner member is spaced
inwardly (not shown) from the corresponding end of the outer member
90.
First integral portions 100 of the inner member 92 define a first
area which extends across the interior of the inner member 92 and
which offers at least as much resistance to passage of smoke as the
filtering material from which the inner member 92 is primarily
formed. These first portions 100, in the embodiment of FIG. 6, are
defined by the end of the inner member 92 remote from the sealed
area at 94 being crimped and preferably sealed in a manner to be
described in more detail hereinafter. In this manner, the use of a
separate baffle or closing element is avoided. Basically, these
first portions 100 preclude preferred entry of the smoke from the
tobacco portion 78 into the interior of the inner member 92 through
this end of the inner member 92 and insure that the smoke will pass
more uniformly through the filtering material of the inner member
92 from the first cavity means 96. As will be seen in FIG. 6, the
first portions 100 in that embodiment are crimped to form a
generally "S" or "Z" shaped cross section, the laterally terminal
edges 102 of which contact the inner surface of the outer member 90
to assist in centering the inner member 92 within the outer member
90 and in defining the first cavity means 96. In the preferred
embodiment, only these laterally terminal edges 102 and the
aforementioned peripheral portions 94 of the inner member 92
contact the outer member 90, the remainder of the outer surface of
the inner member 92 being spaced from the inner surface of the
outer member 90, thereby utilizing the maximum available surface
area for filtration.
Alternative forms of crimping are shown in FIGS. 7, 8 and 9. The
support given to the outer member 90 by the "Y" shaped or cruciform
ribs shown in FIGS. 7 and 8 is better than that given by the
simpler "S" or "Z" crimp shown in FIG. 6. In FIG. 9, a further
alternative form of inner member 92 is shown. In this embodiment,
the walls of member 92 are crimped so as to leave ribs which are
arranged helically around the longitudinal axis of the member 92.
By this means, good support is given to the outer member 90 and the
cross secton of the latter may, when it is made of thin materials,
be kept substantially circular.
Returning to FIG. 6, second portions 98 of inner member 92 define a
second area extending across the interior of the inner member 92
which offers less resistance to passage of smoke than the sealed
area at 94. These second portions 98 may merely be the inner
surface of the end portion of the inner member 92 remote from the
first portions 100 and the second portions 98 define second
elongated, high surface area, cavity means 104. Thus, it will be
seen that the smoke passing through the filter element between
opposite ends thereof must travel through both the first cavity
means 96 and the second cavity means 104 and must pass through the
filtering material from which the inner member 92 is primarily
formed. This construction provides an extremely high surface area
for contact between the filtering material and the smoke, on the
order of seven times or more than the surface area presented by the
end portion of a conventional cellulose acetate filter. Yet, the
construction of this filter, as will be readily recognized,
provides substantially less pressure drop than a conventional
cellulose acetate filter means of the same length. In this manner,
extremely high filtration efficiency will be provided by the filter
means without encountering any difficulty with respect to pressure
drop.
Since the pressure drop of a filter means as hereinabove described
is quite low, it is possible to secure a plug or disc 106 of
cellulose acetate or any other desired material within the open end
of the inner member 92, as shown in dotted lines in FIG. 6. This
disc 106 then serves as the aforementioned "second portions" of the
inner member 92 and may be included, if desired, to merely provide
the filter element 86 with the appearance of a solid plug. Further,
the disc 106 may be utilized to increase the pressure drop of the
filter means 86 with particular "taste" characteristics or to
enhance the physical characteristics of the filtering material from
which the inner member 92 is primarily formed by filtering out
certain constituents of the smoke which would otherwise pass
through the filter means 86. Finally, the disc 106 serves to
provide a second cavity means 104 having both ends closed whereby
an additional smoke-modifying material 108 may be retained in the
second cavity means 104. For example, this additional
smoke-modifying material 108 may be a quantity of loose sorbent
material in particulate form such as activated carbon, silica gel,
or other adsorbents which enchances the vapor phase filtration
efficiency of a filter means as hereinabove described. It should be
understood that this disc 106 is not necessary to the filter and,
in fact, is ordinarily not utilized since it necessitates handling
an additional element. However, for special effects, it may be
included, if desired. Furthermore, the cavity 104 may be closed by
a plug 110 shown by dotted lines. Additionally, in the preferred
embodiment shown in FIG. 7, an additional series of crimps or
further integral peripheral portions 112 extending around a
peripheral portion of the inner element 92 is provided. This
insures the proper passage of the smoke through the filter.
Returning now to FIG. 1, when the tow, or tube, 62 which will be
used to make the inner portion 92 of the filter, leaves the pulling
device 70, it passes into a third curing station 114 which is a
steam jet quite similar to that used in first curing station 60.
Basically, the construction of the steam jet in third curing
station 114 is the same as that used in first curing station 60
with several minor modifications which will be apparent to one
skilled in the art. Steam enters third curing station 114 through
inlet 116 and passes through and around the tow 62 as it moves
through the steam jet. Unlike the first curing station 60, however,
the steam in third curing station 114 need not necessarily run
counterflow to the tow, but may actually pass cocurrently with the
same. In fact, in a preferred embodiment, the steam runs with the
tow rather than counter to the same in third curing station 114.
According to the concepts of the instant invention, this second
steam treatment is an important preconditioning of the rod in order
to prepare the same for the crimping operation to be performed in
crimping station 118. The crimping could be performed without this
preconditioning, but the amount of heat and pressure which would be
necessary renders such a step less desirable. It has been found
that when the tow is preconditioned in third curing station 114,
the crimping can be done extremely easily. The crimping station
118, of course, will impart the desired configuration to the rod,
as shown in FIGS. 6 through 9.
For a further understanding of crimping means 118, attention is
directed to FIG. 10 wherein crimping means 118 is shown in more
detail in elevational view, looking at the device from the rear, or
inlet end. The housing 120 is partially broken away for ease of
illustration. The preconditioned rod 62 coming from the third
curing station 114 enters crimping means 118 at 122. In passing
through crimping means 118, the rod is intermittently contacted by
crimping wheels 124. Crimping wheels 124 are arranged in two pairs
of opposed wheels. The crimping wheels 124, which will be described
more fully hereinbelow, are driven by conventional means, such as
bevel gears 126 which are interconnected by shafts 128 which, in
turn, are powered by an external power source (not shown) through
drive means 130. The crimping wheels 124 are mounted, through the
shafts 128, in heater blocks 132 which also act as bearing
supports. The heater blocks 132 carry a cartridge-type heater (not
shown) and, accordingly, heat the crimping wheels 124.
As can be seen from FIGS. 11 through 13, crimping wheel 124
comprises a plurality of axially projecting first embossing
portions 134 circumferentially spaced around the periphery of the
wheel. A plurality of transverse grooves 136 are also arranged at
spaced intervals around the periphery of the wheel 124, alternating
with the first embossing portions 134. Second embossing portions
138 extend circumferentially around the periphery of the embossing
wheel 124 between first embossing portions 134 and transverse
grooves 136. Second embossing portions 138 include a pair of
circumferential grooves, or valleys, 139 and a plurality of raised
portions, or lands, 141.
Keeping in mind the description of the filter means in FIGS. 6 and
7, and turning momentarily to FIGS. 14, 15 and 16, it will be seen
that the tow 140 emerging from crimping means 118 comprises a
continuous tube crimped at spaced intervals in such a manner that
when cut apart, it will provide a plurality of inner members 92 of
filter elements 86. First integral portions 100 of the inner
members 92 are produced by the first embossing surfaces 134 of the
crimping wheels 124. The additional series of crimps 112 are
produced by second embossing surfaces 138. The peripheral
unembossed areas 142 are the result of the transverse grooves 136.
Since the rod 62 is a hollow tube, the crimped rod 140 retains the
hollow configuration in those areas which have not been compressed
by crimping means 118. This hollow configuration is shown in FIG.
16 wherein the cavity 144 appears.
Returning once again to FIG. 1, the crimped rod 140 emerging from
crimping means 118 passes to fourth curing station 146. Fourth
curing station 146 is an air jet similar to second curing station
64 having air supplied thereto through connection 148. This final
curing stage sets the crimped rod 140 into its final shape. The rod
140 of crimped inner elements 92 is then overwrapped, for example,
with a sheet of ordinary "plug" wrap, such as shown at 150,
bypassing the crimped rod 140 and the plug wrap 150 through a means
152 which is a conventional overwrap garniture, with the assistance
of an endless belt 156. The plug wrap 150 forms an axially
elongated hollow outer element 90, the lateral edges of which may
be secured together to form a longitudinal butt seam, or a
longitudinal lapped seam, as is well known, sealing means 158 being
shown for this purpose.
The continuous rod 160 of overwrapped combined inner and outer
elements 90 and 92 may then be cut in any conventional manner, as
by means schematically shown at 162, to provide a plurality of
segments 164. For convenience in handling, each segment 164 may
initially include four filter elements, the segments being first
further subdivided, as shown by the dotted lines 168 in FIG. 14 to
provide segments including two filter elements. The segments may
then be associated with a pair of tobacco portions and overwrapped
with a tipping paper before further subdividing the same to form
two filtered cigarettes, each including a single filter element of
the type shown, for example, in FIG. 6.
The foregoing detailed description of the present invention is
drawn to the preferred embodiment thereof. In an alternate form of
that embodiment, there is provided a method and apparatus for
making a filter of the type described, which filter further
includes a section carrying an additional material capable of
providing a required filtering or other effect upon tobacco smoke
and unitary with a section without such a material. This additional
material capable of having a filtering or other required effect
upon tobacco smoke can be, prior to its application to the
above-described filter means, in particulate, liquid or suspended
state. Accordingly, method and means are provided in an alternate
embodiment of the present invention for applying such additional
material to the filter means. The additional material, as already
explained, can be any material capable of providing a required
filtering or other effect upon tobacco smoke, and is preferably
finely divided activated charcoal. A method and means of applying
such a material is disclosed and claimed in U.S. Pat. No.
3,371,000, which issued on Feb. 27, 1968. Reference is now had to
FIGS. 17 and 18 wherein the additional steps and apparatus
according to one variation of this embodiment are described. As the
rod leaves the pulling device 70, and prior to entering third
curing station 114, it passes through an applicator device 170.
Applicator device 170 comprises an applicator roll 172, a pressure
roll 174, a fountain roll 176, a further fountain roll 178, a
doctor roll 180 and a trough 182. The trough 182 contains slurry to
be applied to the filter. The fountain roll 176 dips into the
slurry in the trough 182 at its lowest part and is in surface
contact with the further fountain roll 178, which in turn is in
surface contact with the applicator roller 172. The doctor roll 180
is so disposed as to doctor, or meter, the amount of slurry carried
round by the roll 176 to be, ultimately, transferred to the
applicator roller 172. The applicator roller 172 comprises a
plurality of surfaces 184 separated from one another by axially
directed valleys 186. The surfaces 184 conform to an imaginary
cylinder coaxial with the roller 172. Each surface 184 may have an
arcuate length equal to whatever length of "stripe" of the
additional material it is desired to "print" onto the filter means.
Additionally, the surfaces 184 may be separated from one another by
any desired arcuate length. The pressure roll 174 serves to press
the rod 62 into contact with the surfaces 184. The rod 62 passes
into and through applicator device 170 on endless belt 188 which is
entrained about two rollers 190 and 192. The rod 62 passes between
the nip of roller 192 and roller 194 as it enters onto endless belt
188.
In FIG. 18, applicator device 170 also comprises applicator roll
172, pressure roll 174, fountain roll 176, further fountain roll
178, doctor roll 180 and trough 182. The endless belt and its
accompanying drive rollers are not used in this embodiment, the rod
62 merely passing between applicator roller 172 and pressure roll
174. In both FIGS. 17 and 18, it can be seen that as the rod 62
leaves the applicator device 170, it passes into third curing
station 114 where it is again cured with steam before entering
crimping means 118. This curing additionally serves to "set" the
stripe of activated carbon where it has been printed on the rod 62.
It is additionally apparent that the length of the printed stripe
of activated carbon is determined by the size of the filter, the
unprinted areas being those areas wherein the plurality of filters
will be cut apart. 170,
In another variation of this embodiment, the slurry of additional
material, such as activated carbon, or finely divided additional
material, such as activated carbon alone or in combination with a
suitable resin, such as those disclosed in U.S. Pat. No. 3,217,715,
granted to Richard M. Berger et al. on Nov. 16, 1965, or other
additive, is applied to the hollow inner portion 144 (as shown in
FIG. 16) of the tow 62 at the first curing station 60. This is done
by providing a mandrel 20a which is hollow, as indicated by the
broken lines 196. The hollow mandrel 20a is fed, at its rear or
inlet end, with the additional material from a reservoir 198. The
additional material is ejected from the hollow mandrel 20a at its
forward end, in the neighborhood of first curing station 60, to
deposit the additional material in the hollow tube 62. The
additional material is injected in this manner by means of a
pulsating feed to the mandrel. The mandrel 20a, in effect, serves
as a pulsating nozzle. The pulsating feed from reservoir 198 to
hollow mandrel 20a is accomplished by known means which need not be
herein described.
It will, at this point, be apparent to one skilled in the art that
the various steps in the apparatus of the present invention must be
carefully coordinated to insure a properly made and uniform
product. For this reason, the driving means of pulling device 70,
crimping device 118, ad cutting device 162 are separately driven
and synchronized using known synchronization means, or, preferably,
driven by a single driving means through a drive train, including
belts, and pulleys, and gears, so as to insure perfect
synchronization of all moving parts, so that uniform manufacture
will be achieved. Furthermore, in the embodiments of FIGS. 17 and
18, the drive means thereof are also synchronized with the other
stations of the apparatus. By the same token, in the embodiment of
FIG. 19, the pulsating feed of the additional material is so
controlled and synchronized with the other stations of the
inventive apparatus that deposit of the additional material is
controlled in a proper manner.
Having now described the process and apparatus of the present
invention and having set forth various advantages thereof, it
should be apparent that the objects set forth at the outset of this
specification have been successfully achieved. While this invention
has been described with reference to presently 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.
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