Technical Field
[0001] This invention relates to a device for the treatment of filter material for tobacco
products, in particular in the context of a machine for making cigarette filters.
Background Art
[0002] As is known, the production of cigarette filters involves processing of a filter
material consisting of a continuous strip, for example of cellulose acetate, also
known by the term of "tow", obtained from a bale of compressed filter material.
[0003] The strip is made to advance along a predetermined path through processing stations
where it is stretched lengthways, opened out transversely and then impregnated with
plasticizing additives.
[0004] As is known, the step of impregnating the strip occurs at specific applicator devices
which are designed to apply to the strip a flow of plasticizing material, in particular
triacetin, which, at the ordinary operating temperature and pressure of these devices,
is a liquid.
[0005] The strip is thus soaked in a flow of liquid droplets of predetermined size and quantity
so that it absorbs the required quantity of triacetin.
[0006] Downstream of the triacetin application station, there is a station where forming
means produce a continuous cylindrical cord of filter material which, at a wrapping
station, is progressively wrapped in a continuous strip of wrapping material to form
a continuous filter rod. Lastly, a rotary cutting device cuts the continuous rod into
separate filter plugs.
[0007] As is known, the triacetin applicator device comprises a tank extending along and
under the path followed by the strip. The tank contains a certain quantity of triacetin
fed from a reservoir through the agency of a pump.
[0008] In known applicator devices, the tank accommodates a rotary brush, partially immersed
in the triacetin. The brush rotates at a steady speed and thus produces a flow of
liquid droplets which strike the strip of cellulose acetate from below.
[0009] In other prior art devices, nozzles are used to spray the strip from below as it
is moved forward. The nozzles draw the triacetin directly from the tank.
[0010] Furthermore, the prior art devices can treat more than one strip at a time, generally
two strips, which are usually fed along two parallel paths in the same machine.
[0011] In this case, each strip receives the triacetin from respective brushes or nozzles.
[0012] In this case, also, the lid over the tank has a top which is inclined downwardly
from upstream to downstream with reference to the direction of strip feed. The top
of the lid is provided with slight ribbing, or with a ridge defined by a low protrusion,
located centrally, that is to say, along the middle of the tank, so that the triacetin
that collects on the inside surface of the lid is conveyed towards a recycling zone
in a lengthwise direction, that is to say, in the direction of strip feed.
[0013] DE10354924 discloses an example of a device for processing filter tow material used for producing
filters for rod-shaped smoking articles such as cigarettes.
[0014] In the prior art devices, it may happen that the strip does not intercept the flow
completely. The part of the flow that does not strike the strip continues its upwardly
directed movement past the plane in which the strip is moving and then drops onto
the strip from above.
[0015] The prior art devices which are capable of overcoming this problem, however, have
the considerable disadvantage of being limited to treating strips of filter material
of only a single size.
[0016] In other words, the same device cannot be used to treat strips of filter material
of different sizes.
Summary of the Invention
[0017] In this context, this invention has for an aim to provide a device for the treatment
of filter material for tobacco products which is free of the disadvantages described
above with reference to the prior art.
[0018] The technical purpose and aims specified are substantially achieved by a device for
the treatment of filter material for tobacco products comprising the technical features
described in one or more of the appended claims.
Brief Description of the Drawings
[0019] Further features of the invention and its advantages are more apparent in the non-limiting
description below, with reference to a preferred but non-exclusive embodiment of a
device for the treatment of filter material for tobacco products, illustrated in the
accompanying drawings, in which:
- Figure 1 schematically shows a machine for making filters for tobacco products comprising
a device according to the invention;
- Figure 2 is a schematic side view of a first variant embodiment of the device according
to the invention;
- Figure 3 is a schematic side view of a second variant embodiment of the device according
to the invention;
- Figure 4 is a perspective view, with some parts cut away in order to better illustrate
others, of a first embodiment of the device;
- Figure 5 is a perspective view, with some parts cut away in order to better illustrate
others, of a second embodiment of the device;
- Figure 6 is a perspective view, with some parts cut away in order to better illustrate
others, of a third embodiment of the device;
- Figure 7 is a perspective view, with some parts cut away in order to better illustrate
others, of a fourth embodiment of the device;
- Figure 8 is a perspective view of a detail of the device according to the invention;
- Figure 9 is a perspective view of a second variant of the detail of Figure 8;
- Figure 10 is a perspective view of a third variant of the detail of Figure 8;
- Figure 11 shows a step of making the detail of Figure 8;
- Figure 12 shows a step of making the detail of Figure 9;
- Figure 13 shows a step of making the detail of Figure 10;
- Figure 14 is a perspective view, with some parts cut away in order to better illustrate
others, of a second detail of the device according to the present disclosure;
- Figure 15 shows an enlarged detail A from Figure 14.
Detailed Description of the Preferred Embodiments of the Invention
[0020] With reference to the accompanying drawings, the numeral 1 denotes in its entirety
a device for the treatment of filter material for tobacco products according to this
invention.
[0021] The device 1 is used in machines 2 substantially of the type illustrated in Figure
1, used for making filters for tobacco products, in particular cigarettes.
[0022] These machines 2 comprise a reservoir 4 of filter material containing two masses
6 of filter material, only one of which is illustrated in Figure 1. Respective ribbons
8 are unwound from the masses 6 and fed by guide devices of known type to a station
10 for processing the filter material.
[0023] In detail, the station 10 for processing the filter material comprises at least one
blower device 12 of known type which transversely opens out the ribbons 8 and transforms
them into continuous webs 14 of predetermined width. Preferably, the processing station
10 comprises three blower devices 12, located along filter processing and forming
lines 16 as illustrated in Figure 1. The processing station 10 also comprises a device
1 for treating the filter material according to the invention, located downstream
of the blower devices 12 and receiving the continuous webs 14 in order to plasticize
the continuous webs 14 by adding a plasticizing fluid to them.
[0024] After being treated, the continuous webs 14 are fed towards a roller conveying device
18 designed to receive the continuous webs 14 and to convey them towards respective
webs or tapes 22 of previously glued paper. At the zone where the webs 14 reach the
tapes 22, the webs 14 are gathered together into cords by respective conical conveyors
which give them, in known manner, a substantially cylindrical shape.
[0025] After adopting the substantially cylindrical shape, the cords obtained from the webs
14 are parallel to each other and are wrapped in the tapes 22 of pre-glued paper to
obtain respective parallel rods 24 of filter material.
[0026] The rods 24 thus obtained are fed into a quality check device 26, which checks the
rods 24, and then to a cutting head 28, which cuts the rods 24 to obtain respective
successions of filter plugs, not illustrated.
[0027] Described in detail below is the applicator device 1 for the treatment of filter
material for tobacco products according to this invention in a preferred embodiment
illustrated in Figure 2.
[0028] The device 1 comprises a tank 30, having a base 32 and an upper opening 34 and designed
to contain a plasticizing fluid product, in particular triacetin.
[0029] At least one continuous strip 36, defined by the continuous web 14 of filter material
is fed along a respective filter processing and forming line 16. The strip 36 is made
to advance at the upper opening 34 of the tank 30.
[0030] More specifically, the strip 36 is made to advance above the upper opening 34 of
the tank 30.
[0031] The device 1 also comprises means 38 for generating a flow of a plasticizing fluid
directed towards the continuous strip 36 of filter material.
[0032] In a first preferred variant embodiment, illustrated in Figure 2, the flow generating
means 38 comprise a rotary brush 40 provided with bristles 42.
[0033] The brush 40 is located inside the containment tank 30 and is partially immersed
in the triacetin. When the brush 40 rotates, the bristles 42 collect triacetin and,
thanks to a contact element not illustrated which the bristles 42 partially interfere
with as they turn, spray triacetin at the continuous strip 36.
[0034] In another variant embodiment, shown in Figure 3, the generating means 38 comprise
a battery of nozzles 44 connected to the containment tank 30. Through the agency of
a pump not illustrated, the triacetin is sprayed, through the battery of nozzles 44,
at the continuous strip 36 of filter material.
[0035] More specifically, the device 1 comprises screening means 46 for the upper opening
34 of the tank 30. The screening means 46 form a window 48 through which the strip
36 is exposed to the flow of plasticizing fluid.
[0036] The window 48 has fixed dimensions which are less than the dimensions of the upper
opening 34 of the tank 30. Further, the width of the window 48 is substantially equal
to the width of the strip 36.
[0037] Preferably, the width of the window 48 is slightly greater than the width of the
strip 36 so as to guarantee that the triacetin is applied correctly, in particular
on the lateral edges 110 of the strip 36, should the strip 36 become misaligned as
it moves forward.
[0038] Reference is made in particular to misalignment of the strip 36 in a direction substantially
transversal to the direction of strip feed D.
[0039] The screening means 46 constitute a changeover part, that is to say, it can be substituted
according to the width of the strip 36 of filter material to be treated.
[0040] The screening means 46 can be embodied in different ways, all falling within the
scope of the invention.
[0041] Reference will also be made to a device 1 for simultaneously treating two continuous
strips 36 of filter material. This must not be construed as excluding the possibility
of using the device 1 according to the invention for only a single continuous strip
36 of filter material.
[0042] In a first variant embodiment, illustrated in Figures 4, 6 and 8, the screening means
46 are formed by a plurality of elements 50 which are separate from each other. Each
element 50 comprises respective upper walls 52 which are substantially coplanar.
[0043] Further, the walls 52 are substantially parallel, or slightly inclined, relative
to a plane in which the strip 36 lies as it moves forward.
[0044] In a second variant embodiment, illustrated in Figures 5, 7, 9 and 10, on the other
hand, the screening means 46 are formed by a plurality of elements 50 which are connected
to each other. In this case, too, each element 50 comprises respective upper walls
52 which are substantially coplanar.
[0045] The elements 50 have the form of a flat plate 54.
[0046] As shown in Figures 8 and 11, the element 50 is made from a substantially rectangular
flat plate 54 which is folded at the ends of it 56 along respective fold lines 58.
[0047] After being folded, the element 50 comprises the aforementioned upper wall 52 and
two side walls 60 formed by the folded ends 56.
[0048] In a first embodiment, illustrated in Figure 4, the screening means 46 comprise a
first side element 62, a second side element 64 and a third element 66 located at
a substantially central position of the tank 30.
[0049] Thus, respective windows 48 for exposing each strip 36 to the flow of plasticizing
fluid are formed between the first element 62 and the third element 66 and between
the second element 64 and the third element 66.
[0050] More specifically, a first window 68 for exposing a first continuous strip 36a is
formed between the first element 62 and the third element 66, and a second window
70 for exposing a second continuous strip 36b is formed between the second element
64 and the third element 66.
[0051] In this first embodiment, each window 68, 70 may be considered as the plane portion
extending between two adjacent elements 50 and relative to which the upper walls 52
of the elements 50 are co-planar with each other.
[0052] In a second embodiment, on the other hand, the screening means 46 have the form of
a single flat plate 54 having at least one unbroken aperture 72 cut into it.
[0053] As illustrated in Figures 9, 10, 12 and 13, the flat plate 54 has an unbroken aperture
72 for each of the continuous strips 36. In other words, each unbroken aperture 72
forms an opening 74 which in turn forms the window 48 for exposing the respective
strip 36 to the flow of plasticizing fluid.
[0054] The apertures 72 are substantially rectangular in shape and equal in size.
[0055] In this second embodiment, the elements 50 can be identified as portions of the flat
plate 54 since they are connected to each other. For example, with reference in particular
to Figures 9 and 12, a first side portion 76, a second side portion 78 and a third
central portion 80 can be identified on the plate 54, these portions corresponding
to the first side element 62, the second side element 64 and the third central element
66, respectively.
[0056] The side walls 60 are here formed by two longitudinal bands 82 of the flat plate
54, defined by the respective fold lines 58, which are folded to form, as just stated,
the side walls 60 of the elements 50. The side walls 60 are in this case joined by
the material of the plate 54.
[0057] Each element 50 has precise, preset dimensions. Thus, once the elements 50 are fitted
on the containment tank 30, each exposure window 48 has precise dimensions.
[0058] Furthermore, for this reason, the dimensions of the window 48 are fixed and not adjustable.
[0059] When the screening means 46 are formed by elements 50 which are connected to each
other and hence obtained from a single plate 54, it is instead the unbroken aperture
72 that is suitably dimensioned according to the width of the continuous strip 36
to be treated. Thus, in this case, too, once the elements 50 are fitted, the dimensions
of the window 48 are fixed and may not therefore be varied.
[0060] Furthermore, in the case where the flow generating means 38 comprise the rotary brush
40, the device 1 comprises a central crossbar 86 which supports the rotary brush 40.
The crossbar 86 supports the brush 40 by means of a protrusion 88, which has a hole
90 through which the brush 40 itself passes (Figures 6 and 7).
[0061] Figure 6 shows a third embodiment of the screening means 46, which comprise the first
side element 62 and the second side element 64, and centrally, the third central element
66 and a fourth central element 92. The third element 66 is located between the first
strip 36a and the central crossbar 86, whilst the fourth element 92 is located between
the central crossbar 86 and the second strip 36b.
[0062] Similarly to the second embodiment, Figure 7 shows a fourth embodiment of the screening
means 46 where each exposure window 48 is formed by an unbroken aperture 72 in the
flat plate 54.
[0063] In this case, owing to the presence of the crossbar 86 supporting the brush 40, the
screening means 46 comprise the first side element 62 and the third central element
66 which are connected to each other by the respective side walls 60, and the second
side element 64 and the fourth central element 92 which are also connected to each
other by the respective side walls 60.
[0064] More specifically, with reference also to Figures 10 and 13, the screening means
are embodied by two flat plates 54, each having a single unbroken aperture 72 and
corresponding to only two elements 50 connected to each other.
[0065] The containment tank 30 also comprises lower supporting means 94 for the screening
means 46.
[0066] More specifically, the supporting means 94 interact with the side walls 60 of the
elements 50 of the screening means 46.
[0067] In a first preferred variant embodiment, illustrated in Figures 2 and 3, the supporting
means 94 are defined by a duct 96, located inside the containment tank 30 and comprising
a first side wall 98 and a second side wall 100.
[0068] More specifically, the flow of plasticizing fluid runs inside the duct 96 in the
direction of the continuous strip 36 of filter material moving forward.
[0069] The first side wall 98 and the second side wall 100 are inclined so as to better
accompany the flow of plasticizing fluid. The inclined walls 98, 100 also make it
possible to delimit the fluid flow so as to better direct it towards each strip 36
as the latter moves forward.
[0070] The duct 96 has a bottom opening 102 and a top opening 104. Preferably, the cross
section of the duct 96 diverges from the bottom opening 102 to the top opening 104.
The bottom opening 102 faces the means 38 for generating the flow of plasticizing
fluid, whilst the top opening 104 faces the strip 36 of filter material being moved
forward.
[0071] The screening means 46 are fitted inside the duct 96.
[0072] More specifically, the side walls 60 of each element 50 are shaped in such a way
as to adapt to the inclination of the walls 98, 100 of the duct 96. Thus, when inserted,
the elements 50, and hence the screening means 46 as a whole, are supported by the
side walls 98,100 of the duct 96. In particular, each element 50, supported by the
walls 98,100 of the duct 96, reaches a stable position inside the duct 96 itself.
[0073] The element 50 reach this position under each continuous strip 36.
[0074] Thus, more precisely, in this variant embodiment, the lower supporting means 94 are
embodied by the side walls 60 of the elements 50 of the screening means 46 and by
the inclined side walls 98,100 of the duct 96.
[0075] In a second variant, not illustrated, the containment tank 30 comprises abutments
on the side walls of the tank 30 itself or on the side walls 98,100 of the duct 96.
[0076] In this case, too, the side walls 60 of the elements 50 of the screening means 46
interact for example with the abutments by resting thereon. In this case, too, the
elements 50 reach a stable position inside the duct 96, thus guaranteeing optimum
screening of the flow of plasticizing fluid.
[0077] An advantageous aspect of these variant embodiments is the ease of positioning and
fitting the elements 50 and hence the screening means 46.
[0078] Changing over to a different size continuous strip 36 of filter material, when the
strip 36 to be treated has to be varied in width, is advantageously quick and easy
and allows downtime due to changeover to be reduced owing to the simplicity of construction.
[0079] The device 1 also comprises means 106 for aligning the advancing strip 36 with the
exposure window 48 (Figures 4-7).
[0080] The aligning means 106 comprise a plurality of pins 108 which are substantially perpendicular
to the plane in which the strip 36a,36b lies.
[0081] More specifically, the alignment means 106 are embodied by a plurality of pins 108
located at the infeed of the device 1.
[0082] The alignment means 106 are also further embodied by a plurality of pins 108 located
at the outfeed of the device 1.
[0083] The purpose of the pins 108 is to prevent misalignment of the strip 36 as it advances.
As already stated, such misalignment might prevent the strip 36 from correctly intercepting
the flow of plasticizing fluid, resulting in zones without plasticizing fluid on the
strip 36 itself.
[0084] Each strip 36 to be treated is kept aligned by at least one pair of pins 108 which
come into contact with the lateral edges 110 of the strip 36, thereby preventing misalignment.
[0085] At the infeed of the device 1, each strip 36 is kept aligned by contact of its lateral
edges 110 with a first pair 112 of pins 108.
[0086] In the same way, at the outfeed of the device 1, each strip 36 is kept aligned by
contact of its lateral edges 110 with a second pair 114 of pins 108.
[0087] The pins 108 are movable along a direction transversal to the direction D of strip
36 feed. This allows alignment with the exposure window 48 to be adjusted precisely
according to the size of the strip 36.
[0088] The pins 108 are partly inserted in a respective guide 116 and, in the event of changeover
to a different size strip 36, the pins 108 of each pair 112, 114 are moved along the
guide 116 to adjust their spacing according to the width of the strip 36 to be treated.
[0089] Once the correct position is reached, the pins 108 are locked in place by fastening
means not illustrated.
[0090] The pins 108 are substantially cylindrical in shape. Since the pins 108 come into
contact with the lateral edges 110 of the strip 36, the pins 108 are made of a material
which has a low friction coefficient so as to prevent damaging the strip 36 by rubbing
against it as it moves forward. Further, the pins 108 may be mounted so they can rotate
freely in the respective guides 116, in such a way that their rotational movement
accompanies the forward movement of the strip 36.
[0091] Adjusting each pair 112, 114 of pins 108 is also very easy and thus they, too, allow
changeover to be performed more quickly.
[0092] The device 1 also comprises a lid 118 for closing the containment tank 30.
[0093] As shown in Figure 14, the lid 118 is located above the tank 30 and between the first
pair 112 of pins 108 and the second 114.
[0094] Preferably, the containment tank 30 comprises a respective supporting ledge 120 for
the lid 118, running parallel to the direction D of feed of the strips 36. In particular,
the ledge 120 keeps the lid 118 at a certain distance from the plane in which the
strip 36 lies, so as to allow the strip 36 itself to slide freely.
[0095] Inside it, at its inside surface 118a, the lid 118 comprises at least one run-off
element 122 for draining off excess plasticizing fluid, if necessary.
[0096] The lid 118 also has an inclined top surface 124 which makes the cross section of
the lid 118 convergent along the direction D of strip 36 feed, so as to facilitate
run-off of excess fluid.
[0097] When the flow of plasticizing fluid is generated, it may happen that part of the
plasticizing fluid fed towards the strip 36 moving forward may go past the plane in
which the strip 36 lies and be deposited on the inside surface 118a of the lid 118.
[0098] In order to prevent droplets of fluid from dropping back onto the strip 36, the lid
118 is provided on its inside surface 118a with the run-off element 122, which prevents
the fluid from being supplied in excess.
[0099] As shown in Figure 15, the run-off element 122 comprises at least one rib or projection
126, lying in a plane parallel to the direction D of strip 36 feed and able to recover
the excess fluid droplets that have been deposited on the inside surface 118a of the
lid 118 and to direct them towards a fluid recycling zone Z.
[0100] Preferably, the lid 118 is provided with a plurality of parallel ribs or projections
126 which can optimally direct towards the recycling zone Z the excess triacetin which
has been deposited on the inside surface of the lid.
[0101] The run-off element 122 might otherwise be embodied by a plurality of grooves 128
formed on the inside surface 118a of the lid 118 and also able to collect the fluid
droplets and direct them towards the recycling zone Z.
[0102] As may be inferred from Figures 2 and 3, the recycling zone Z is located at the front
of the containment tank 30, near the front pins 108.
[0103] At the zone Z, the tank 30 has at least one drainage surface 130, which is inclined
in the direction of the means 38 for generating the flow of plasticizing fluid.
[0104] More specifically, if more than one strip 36 is treated at a time, it is preferable
to associate each strip 36 with respective drainage surfaces 130 for the excess fluid
to be recycled, as illustrated in Figures 4 to 7.
[0105] The drainage surfaces 130 receive the excess droplets from the run-off element 122
and direct them back into the tank 30 in the direction of the fluid flow generating
means 38.
[0106] The invention described above provides a device for the treatment of filter material
for tobacco products which is able to process strips of filter material of different
sizes.
[0107] Also, the device guarantees effective protection for the strips and at the same time
guarantees that the plasticizing fluid is added to the filter material in the correct
quantity.
[0108] Moreover, the invention allows changeover time to be reduced, thanks to the ease
with which the screening means can be substituted.
[0109] The invention described above is susceptible of industrial application and may be
modified and adapted in several ways without thereby departing from the scope of the
inventive concept. Moreover, all the details of the invention may be substituted for
technically equivalent elements.