Note: Descriptions are shown in the official language in which they were submitted.
~3~3~5
This invention relates to the treatment of filamentary
and other fibrous materials in order to impart certain desired
or selected properties thereto and is more particularly con-
cerned with the production of filter-rod stock for use in the
manufacture of filter-tip cigarettes.
Filters for ciqarettes are commonly formed from a multi-
plicity of filaments arranged in essentially longitudinal aliqn-
ment with substantially all of such filaments extending continu-
ously from one end of the filter to the other. In the production
of such a filter, a tow or bundle of upward of several thousand
substantially longitudinally aligned continuous filaments, pre-
ferably already suitably crimped, is passed through one or more
devices that serve essentially to open up the advancing tow. The
result is that the tow assumes the appearance more or less of a
continuous band or web of varyingly increased width. The many
different arrangements that have been proposed to accomplish
this objective range from those which ordinarily do little more
than flatten, widen, and/or smooth out the tow to those which
also separate the filaments as necessary to bring the same more
nearly into longitudinal alignment and/or to effect deregistra-
tion of the crimp in adjacent filaments.
The open tow may be treated with a selective additive
material in order to impart a desired property or effect thereto.
Such additive material may be in liquid form. Illustrative types
of liquid-form additive materials comprise plasticizers such as
glycerol triacetate ~triacetin) and triethyl citrate, lubricants
such as light mineral oil and diethylene glycol, and antistatic
aqents such as mixtures of magnesium chloride in water and
diethylene glycol.
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o
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The resultinq opened, spr~ad and liquid treated tow may
then be passed without any further treatment essentially direct-
ly to the garnit~re of a filter-roa maker, wherein it is con-
densed to provide a continuous filter-rod stock having a cross-
S sectional area corresponding to that of the filter-tipped ciga-
rettes to be produced. Customarily, the desired filter rods are
obtained by appropriately cutting or severing such continuous filter-
rod stock as it issues from the garniture.
A number of procedures is available for applying a liguid
form material to the advancing tow. A liquid-form treating
material such as a plasticizer or other filament-bonding agent,
for example, is customarily discharged through appropriately
arranged and designed nozzles, wicks or spray-~orming devices
such as rotary brushes such as are disclosed in U.S. Defensive Pub-
lS lication T ~74~005 published May 19, 1970 or rotary discs
such as are disclcsed in ~.S. Patents Nos. 3,387,992 and
3,818,863. However, all of these prior art applicators pass
excess liguid; that is to say, liquid not picked up by the tow
to a holdinq device or tank and therefore there is no mechanism
to compensate for unequal liquid pick-up.
Regardless of the method employed for applying the liquid
form material to the tow band, it is necessary to monitor and
control the amount of liquid form material applied to the tow.
The most common method of the prior art for determining the amount
of liguid form added to the tow band i5 the so-called wet/dry
weight method. In this system, a wet rod sample is taken and a
weight measurement made and then liquid application is discon-
tinued. When sufficient time has elapsed to assure there is no
liquid application, dry rod samples are taken and a dry weight
measurement is made. This method of ~onitoring is, of course,
a discontinous method and is inherently wasteful. An improved
prior art system for determining liquid add-on is a metering
system ~ased on the use of a pneumatically eontrolled, valveless,
r ~ ~ i
3~
positive-displacement pump. This pump supplies plasticizer to
the plasticizer-application booth at a rate that is egual to
the rate at which the plasticizer is applied to the tow. A
pneumatic system governs the pump speed and is activated by a
float valve in the applicator booth~ When the aepth of plastici-
ser in the booth decreases from a nominal, predetermined level,
the float valve closes, creating a pressure differential across
a diaphragm. The diaphragm then opens a valve that controls
the supply of air to an air-ariven motor that drives the pump.
The pump speed relates to the position of the float valve and
is proportional to deviations in the depth of the plasticizer
in the booth. The pump is fitted with an optical sensor that
detects the rotation of the pump. As the pump rotates, a
series of electrical impulses is produced. The frequency of
these impulses is proportional to the rate at which the pump
rotates, and therefore to the flow rate of the plasticizer.
Since the pump has a positive displacement, each impulse can
be equated to a known quantity of plasticizer, for example, in
mg/pulse.
In theory, if the depth of plasticizer is maintained con-
stant, the amount of plasticizer pumped to the applicator booth
can be assumed to equal the amount applied to the tow during
any particular time interval. The positive-displacement pump
is then used to establish the amount of plasticizer .hat flows
~5 into the system over a period of time. With this irformation
alone, an instrument can be provided that will display a reading
of the amount of plasticizer flowing onto the tow, for e~ample,
in mg/min.
As previously noted in all of the prior art liquid applicator
processes and apparatus for the treatment of tow, liquid which
~3~Z3Ç~
is not applied to the tow is returned to a hold;ng device
and- must be measured in order to determine the liquid add-on.
The disadvantages of these monitoring methods include the prob-
ability of untreated cigarette filter rods entering production,
loss Of production itself, as well as waste. Moreover, none of
the prior art processes and apparatus have a variable control
for the amount of liquid applied to the tow; that is to say,
variations in tow band width will cause corresponding variations
in liquid pick-up for which there is no compensation in prior
art processes and apparatus.
It is therefore an object of this invention to provide a
process for the preparation of cigarette filter rods wherein
liquid add-on is constant in spite of tow band width variation.
It is another object of this invention to provide a liquid
lS form add-on apparatus for the treatment of continuous filament
tow in the preparation of cigarette filter roas wherein only one
liguid flow line need be monitored.
It has been discovered that the aforementioned objectives
can be achieved in a process for controlled application of a
liquid to a filamentary material by feeding liquid at a con- i
stant rate to an applicator device suitable for applying liquid
to a running band of filamentary material and causing any liquid
not picked up by the tow band to be returned directly to the
applicator device. Preferably the liquid is fed at a constant
rate by a positive displacement pump and the liqu;d applicator
device is a rotatable brush or a rotatable disc. The apparatus
of the instant invention employs a housing provided with means
for draining any liquid not returned by said filamentary material
back to the applicator means.
,~
_ 5 _
'~3~Z3~
This invention relates to a process for controlled application of
a liquid to a filamentary material comprising, feeding said liquid at a
constant rate by means of a first positive displacement pump into the
center of a rotatable disc applicator device suitable for applying liquid
to a running band of filamentary material, and causing any liquid not
picked up by said band of filamentary material to be returned directly to
said applicator device by means of a second positive displacement pump.
~ .
D `:
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A better understanding of the invention may be had from a
discussion of the drawings wherein:
FIG. 1 is a schematic flow diagram of the controlled fluid
applicator of this invention suitable for use with a brush type
liquid applicator.
FIG. 2 is a cross sectional view o~ a brush type liquid
applicator suitable for use in this invention.
FIG. 3 is a projected view of the bottom portion of the
brush type liq~id applicator of FIG. 2 of the drawi~gs.
~IG. 4 is a schematic flow diagram of the controlled
fluid applicatOr of this invention suitable for use with a
disc type liquid applicator.
FIG. S is a cross sectional view of a disc type liquid
applicator suitable for use in this invention.
FIG. 6 is a projected view of the bottom portion of the
disc type liquid applicator o FIG. 5 of the drawings.
FIG. 7 is a graph illustrating the effect of cigarette
tow band width change.
Turning to FIG. 1 of the drawings, liquid from a tank
member 1 is pumped by means of a centrifugal pump 2 to a pump
supply reservoir 3, pump supply resevoir being maintained at
a constant level by means o an overflow pipe 4 which feeds
excess liquid back to plasticizer tank 1. A positive displace-
ment pump 5 then feeds liquid from the constant~pump supply re-
servoir to the delivery manifold 6 of the liquid applicator
device 7, delivery manifold 6 supplying liq~id to brush member 9
of liquid applicator device 7. It should be understood that a
single positive displacement pump or any plurality of positive
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3~231~
displacement pumps which are preferably gear pumps may also be
employed for purposes of this inven~ion. By metering plasticizer
into the chamber with a gear pump, t~e revolutions per minute of
the pump provides the flow information required. A three-way
S valve 8 is positioned intermediate gear pumps 5 and delivery
manifold 6 in order that liquid feed to the delivery manifold
may be diverted bac~ to the plasticizer tank in the event of a
discontinuation of feed of material to the applicator chamber 7.
As can be seen in FIGS. 2 and 3 of the drawings, the brush
type applicator suitable for use in conjunction with this inven-
-tion employs a housinq or.cabinet 21 made.of any suitable material
and having detachable top and bottom spections. Preferably the
bottom portion of the housing 21 consists of side walls 22 ana
23, front and rear walls 24 and 25 respectively, and a floor 26.
The housing floor 26 extends from the lowermost edges of the
side walls 22 and 23 at a relatively gentle downward slope.
Positioned near the lowermost point of floor member 26 is
delivery manifold member 30, delivery manifold member 30 being
positioned between drain-back dam 26a and brush member 31, the
peripheral portion of brush member 31 ac~uall~ contacting de- _
livery manifold mmember 30. In order to facilitate drainage
and cleaning operations, a drain slot 32 is positioned through
housing floor member 26 immediately beneath brush member 31.
The ceilinq 27 of the housing 21 is closed and consists o~ a
pair of sections extending toward one another at an incline
steep slope from the uppermost edges of the side walls. In
Qperation, a constant flow of liquid is continuously supplied
through the elongated slot in delivery manifold 30, liquid being
L
~3~36
pic~ea up by brush member 31 and deposited on tow passing through
housing member 31. Baffle members 33 and 34 are positioned on
either side of-brush member 31 to insure that liquid projected
by brush member 31 is properly directed~ Any liquid not picked
~p by the tow due to liquid by pass or variations in tow width
is caused by the design of chamber member 21 to be returned to
brush member 31 and then recycled by the brush member 31 to the
advancing tow line. More specifically, liquid not applied to
the tow band collects from the ceiling 27 of the housing 21 and
flows downwardly into the channel sections of baffle members 27a.
Liquid then flows from baffle members 27a into side channels 29
and thence into drainback gutter 29a~ Liquid continues to flow
down sidewalls 22 and 23 ana collects in drainback dam 26a. The
drain-bac~ dam 26a distributes liquid uniformly back to brush
member 31. Drain-back dam member 26a is also useful in facilitat-
in~ cleaning of the apparatus.
The monitored fluid applicator of this invention is also
suitable for use in conjunction with disc-type liquid appli-
cation. A better understanding of this applicatar may be had
from FIGS. 4 through 6 of the drawings:
Turning to FIG.4 of the drawings, which is a flow sheet,liquid from a tank member 41 is pumped by means of pump member 42
through a three-way solenoid valve 43 into the center of a rotat-
inq disc applicator 44 which is positioned beneath a tow band
~not illustrated) passin~ through applicator chamber 45. Liquid
distributed by disc member 44 and not absorbed by the tow, flows
to the bottom of chamber member 45 which is~equipped with a
drain 46 and flows to a three-way solenoid valve 47 which directs
:,
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liquid flow to a centrifugal pump 48. Pump member 48 in turn
directs the flow of liquid back to solenoid valve 43 which in
turn directs the liquid back into disc member 44. Equilibrium
is achieved by the pump and valve arrangement of this invention
and the liquid add-on level is controlled and equal to the pump
member 42. When dry runs are desired, that is to say when it
is desired to manufacture rods without any liquid addition,
plasticizer is pumped from tank member 41 by positive displace-
ment pump member 42 to solenoid valve member 43. Solenoid valve
member 43 in turn directs liquid back to tank member 41. In
addition, liquid is pumped from tank member 41 through solenoid
valve member 47 by centrifugal pump member 48. Liquid from
pump member 48 is directed to solenoid valve member 43 and in
turn flows back to tanX member 41, thereby maintaining flow
through centrifugal pump member 48 so as to prevent pump member
48 from running dry. It should be understood, however, that
centrifugal pump member 48 may be replaced with other pump
members such as for instance vane pumps, lob-type pumps, or
other semi-positive displacement pumps.
A better understanding of the mechanism of the disc-type
- ~ plasticizer applicator may be had from a discussion of FIGS. 5
and 6. As can be seen in ~IG. 5, housing member 45 consiStS of
an upper housing section 49 ana a lower housing section 50, upper
housing member 49 being suitably baffled for recycling of liquid
not retained by the tow. More specifically, liquid not re-
tained by the tow is directed by baffle members 51 to the side
walls (not illustrated~ of chamber member 45, chamber member 45
having flat and substantially horizontal side walls covered by
_ g
' ' " ' . ' ' ' . " I ;' ' " ` ' ' ' ' ' ' ' '. ' ' '
~3fl~3~i
a peaked roof, liquid flowing from baffle member Sl down the
siae walls of chamber 45 into drain 46 positioned at the bottom
of the lower section 50 of chamber member 45. The geometry of
the lower section 50 of chamber membex 45 is such that the down-
ward flow of liquid to drain member 46 is assured.
The lower section S0 of chamber member 45 consists of a
pair of floor sections 55a and 55b extending toward one another
at a relatively gentle downward slope and terminating at a pre-
determined distance from one another essentially medially of
the lower section 50 ! thereby leaving an elongated rectangular
opening 56 extending entirely across the housing floor.
Arranged below the opening 56 is a well 57 defined by two ver-
tical, trapezoidal side plates 57a and 57b depending downwardly
from the facing edges of floor sections 55a and 55b, two slant- ;
ed end plates 57c and 57d secured to the downwardly converging
edges of the plates 57a and 57b, and a horizontal bottom plate
57e secured to the lowermost edges of the plates 57a to 57d.
Within the well 57 of lower section 50, a liquid spraying
disc 44 is arranged for rotation in a plane which is substantial- ,
ly parallel to and centered between the well side plates 57a and
57b. The disc 44 is essentially shaped in the manner of a
narrow mouthcup-like receptacle of the type such as is disclosed
in U.S. Patent No. 3,387,992
Disc mem~er 44 is driven, preferably by a motor 54 located
external of the well 57. It should be understood that while a
single disc member 44 has been illustrated, that a plurality of
discs may also be employed in either a side-by-side or back-to-
- back arrangement. Liquid is introduced to the disc through port
member 58 located preferably in axial alignment with the axis of
rotation of disc member 44. As previously noted, the total
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number of discs may vary but, in any event, should be sufficient
to ensure that a steady state of recycled liquid is achieved;
that is to say, when band width is reduced resulting in a high-
er recycle of liquid, a suffi~ient number of recycled discs should
be present to quickly restore steady-state conditions. Prefer-
ably, the disc-type or brush type applicator can be equipped
with pressure or flow sensing switches to prevent overfilling
of the plasticizer tank should the pump drive fail or should the
pump drives fail resulting in production of untreated rods, the
plasticizer flow rate can be determined by means of an rpm de-
tector, employed in conjunction with positive displacement
pump 42. I~ so desired, information from the rpm detector may be
processed through a suitable conversion device which in turn
activates a digital display of the liquid flow rate~ It should be
understood that suitable filtering and particle trapping systems
may also be incorporated in the apparatus of this invention.
The principle of the present invention will be more fully
understood from the following examples wherein data has been
generated employing the brush-type applicator system. It should
be understood, however, that comparable results will also be
obtained when the disc type applicator of this invention is
employed.
Example
A cigarette tow composed of 4.0 DPF cellulose acetate fila-
ments having a total denier of 39,000 is passed through an
applicator chamber constructed substantially in the form as
illustrated in FIGS. 2 and 3 o the drawings. The to~ is pro-
cessed at a linear speed of 400 meters per minute. The brush
member of the applicator device is rotated at a speed of 3400
revolutions per minute. Triacetin liquid plasticizer is pump-
ed to the brush at a rate of 220 grams per minute.
1~3~Z3~
As a control, a brush applicator system 54-FA-l manu-
- factured ~y Hauni-Werke ~orber ~ Co. KG of Hamburg, West
Germany which employs a holding tank or booth for liquid not
picked up by the tow was operated with an identical tow band
S with the brush nlember rotated again at 3400 revolutions per
minute and the plasticizer booth supplied with plasticizer at the
rate to set initial plasticizer additives at a nominal 9% The.
band width of the tow band being passed into each applicator
device is reduced by altering the air flow to the spreader box,
positioned in advance of the applicator chamber. The data genera-
ted is as set forth in the following table:
BAND WIDTH CHANGE
HAVNI INSTANT
INVENTION
Time Rod wgt Rod wgt
(Min) gms/100 rods gms/100 rods
73.3 81.9
1/4 73.5 82.
1/2 73.7 81.9
~ 1 0 74 0 82 20
1 1/4 73.8 82.0
25 * 2 73 8 82,0
2-1/2 71.7 79.4
2-3/4 71 7 7890 8
3_1/2 72 90 80 9
*At two minutes, the band width was changed
from 10 inches to 7 inches.
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9~3423~
As can ~e seen from the table and also from the graphic
representation set forth in FI~. 7 of the drawings, which
plots rod weight against time, with the prior art system,
rod weight dropped when tow band width was reduced. However,
when the apparatus of the instant invention is employed, rod
weights are quickly restored to the preselected weight level.
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