CH619847A5 - Tobacco smoke filter rod - Google Patents

Abstract

The rod is formed of continuous filaments (2) bound together at points of contact surrounding a smoke-permeable core formed by adsorbent particles bound together by means of a binder, this core extending at least partly along the length of the rod. This rod is made from a roving (2) containing (10) a heat-activatable binding agent and formed into a channel (55) by a shaper (12). There is deposited (100) continuously into this channel (55) a line, or longitudinally separated cells, of a mixture of adsorbent particles and thermoplastic binder. A tubular shaper (18) compresses the roving (2) and the deposited mixture into a rod shape (26) by heating them using steam. The rod (26) is then cooled and cut into predetermined lengths. The resulting rod is stronger and simpler to make than known filter rods. <IMAGE>

Description

The present invention relates to a tobacco smoke filter rod, its manufacturing process and an apparatus for carrying out this process.

Smoke filter rods are known comprising cells spaced apart longitudinally between them and containing granules of adsorbent particles.

The method of manufacturing these rods consists in forming a continuous filter rod, for example in tow or in paper, in cutting this rod longitudinally over a part of its diameter, approximately two-thirds, in forming cavities inside the open rod, to deposit granules in these cavities, to close the rod and to wrap it in a sheath. This rod is then cut transversely into segments to form smoke filters for cigarettes.

This type of rod is relatively delicate, because its resistance is greatly reduced by the longitudinal cut; the quantity of stems destroyed by handling errors is quite large. The particle granules are liable to migrate out of the cavities, along the longitudinal cut.

In addition, the cutting of the rod into segments must be done outside the cavities containing the granules, otherwise the latter escape from the cavity.

The object of the invention is to form a sturdy smoke filter rod, which can be handled without damage during the manufacture of cigarettes, in which any migration of particles is avoided and which can be cut in a cavity containing particles without the latter escape from said cavity.

To this end, a smoke filter rod according to the invention is characterized in that it comprises a body, permeable to smoke, formed of continuous filaments linked together at points of contact and surrounding a core permeable to smoke. , made of

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adsorbent particles agglomerated together by means of a thermoplastic binder, this core extending at least partially over the length of the rod. The core may be in the form of a plurality of cells spaced longitudinally between them.

The rod is preferably produced continuously and is divided into shorter segments; when the core is not continuous, but is in the form of spaced cells, the rod initially manufactured continuously can be divided transversely, through and / or between the cells.

The method of manufacturing the smoke filter rod is characterized in that continuously conveys, longitudinally, in the form of a strip with a channel cross section, a wick formed of a material of continuous filaments, filtering the smoke , containing a hot-activating agglomerating agent for the filaments, a bead is continuously deposited, along the base of the channel section, in the form of a continuous line or of separate cells spaced apart longitudinally, a mixture of particles, an adsorbing agent and a thermoplastic binder, the wick is compressed and the deposited mixture of particles, by continuous passage through a tubular former, a hot fluid is circulated through the wall of the former , in order to impregnate and heat the rod and activate said heat-activatable agglomerating agent and said thermoplastic binder, with a view to forming a continuous filter rod of filaments linked together, having a core of agglomerated adsorbent particles stretching continuously through this rod, or a core formed of separate cells spaced apart longitudinally. The continuously formed rod can be cut transversely, in shorter lengths, as already mentioned.

Activated charcoal is the preferred material for use as a particulate adsorbent due to its high adsorption capacity, although other materials may be used in addition to, or in place of, activated charcoal. into particles with filtering properties, for example silica gel, activated alumina, perlite, sepiolite, fuller's earth, magnesium silicate, metal oxides such as iron oxide, and combinations of these products. The coal may be of the type of ordinary coal, so-called sparrow-head coal, or petroleum-based coal, the coal and the binder preferably having approximately the same bulk density, for example from 0.16 to 0, 50 g / cm3 for carbon, and from 0.38 to 0.42 g / cm3 for the binder.

Polyethylene and the like thermoplastic resins can be used as thermoplastic binders for the adsorbent particles. Commercially available polyolefins, such as polyethylene and polypropylene and their copolymers, are not toxic and are of good thermal stability, and provide a solid bond without obstructing the pores of the particles of the adsorbent, which allows to retain the adsorbing power in the finished product. These materials are therefore particularly suitable for use as thermoplastic binders. Other polyhydrocarbons can be used in place of, or in addition to, polyethylene or polypropylene, in particular hydrocarbon polymers containing 4 to 10 carbon atoms, as well as a variety of other thermoplastic materials having indices suitable for melt flow, such as vinyl acetate and other vinyl homopolymers and copolymers, plasticized cellulose acetate, polyester resins, friable polyhydrocarbon resins such as Escorez, and combinations of these products. Microporous polyethylene has adsorbent properties and can be used as an adsorbent and / or as a thermoplastic binder.

A small proportion of one or more fillers or of one or more additives can be incorporated into the material forming the core, these products being preferably mixed with the adsorbent material and the thermoplastic binder during an initial mixing operation. For example, natural or synthetic fibers may form part of the core where a low density product is required, and stems or branches of laminated and / or fragmented tobacco may be incorporated, along with additives such as products alkaline and acid modifiers. Metallic fibers may be incorporated and the fillers may contain carbon in fibers, if low weight is of special importance. Chemicals acting on the taste of the smoke passing through the nucleus can be added and, in particular, certain active additives can be incorporated which eliminate a certain number of harmful constituents from tobacco smoke and consequently increase the effectiveness of the smoke. filtered. Mention is made, as examples of such additives, of polyvinyl acetate, of polycarbonates obtained by reaction of bispholol A and of diphenylcarbonates, of polyamides of the nylon type, for example nylon 6, nylon 6/6 and nylon 6/10, modified cellulosic resins, for example cellulose acetate and dimethylcellulose, natural powdered gums, carbohydrates, for example various sugars, powdered calcium carbonate and fibrous pulp wool. Additives having an average melting temperature or lower than the temperature at which the mixture is subsequently heated, can be used as additional binders. Certain resins mentioned as additives, for example polyvinyl acetate, have already been indicated as suitable binders.

The core may contain 5% by weight or less of thermoplastic binder, or of the order of 50% by weight, and from 50% to 95% by weight of adsorbent particles. Preferably not more than 40% by weight of thermoplastic binder is used, and not less than 60% by weight of adsorbent particles. The most satisfactory mixtures for the core comprise at least 6.5%, but not more than 30% by weight of thermoplastic binder, and from 85% to 93.5% by weight of adsorbent particles (for example activated carbon ).

The adsorbent particles, together with a filler or additive to be incorporated, can be intimately mixed with the particles of the thermoplastic binder. The latter are preferably substantially smaller than the particles of the adsorbent material, so that they adhere to them in the form of a powder-like coating, during mixing. A predominant part, for example at least 80%, of the adsorbent particles can be 9 to 200 times, preferably 9 to 60 times, larger than the binder particles. Each particle of adsorbent in the mixture is thus separated from the neighboring adsorbent particles by an adjoining layer of thermoplastic powder which softens or melts by heating, which ensures the formation of a still porous core firmly bonded. Particles of thermoplastic binder with an average diameter of 100 µm or less, preferably 50 µm or less, are particularly suitable, however at least 80% of the adsorbent particles are preferably about 0.149 mm to 1.41 mm to 1.68 mm, but may be of a fineness of the order of 0.074 mm. The fillers or additives employed are preferably in particles of small dimensions, for example of 50 µl or less.

Instead of such a mixture of separate particles of adsorbent and thermoplastic binder, it is possible to use adsorbent particles coated with thermoplastic binder. For example, an aqueous polyethylene emulsion can be mixed with activated carbon particles to form a thermoplastic coating thereon, the coated particles, with the material used as filler or the additive, if necessary, forming the mixture into particles. of the nucleus. By simultaneous mixing of at least part of the resin in the form of an emulsion in a liquid carrier, the formation of a homogeneous mixture is greatly facilitated and more precise control of the quality of the product is made possible.

The initial mixing of the particles of adsorbent and of thermoplastic binder, with or without filler or additive, can be carried out in a traditional mixing apparatus. Type s mixers

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comprising a helical or ribbon-type agitator may be suitable and simultaneously ensure mixing and kneading, so that the particles are suitably treated during mixing.

The filamentary material of the wick is preferably creped. A preferred material for the wick is cellulose acetate, although other continuous filament materials may be used, these materials comprising polyolefins, for example polyethylene, polypropylene and copolymers of ethylene and propylene with other olefins ; polyamides such as nylon; and polyesters such as polyethylene terephthalate. The hot-activatable binding agent can be a plasticizer for the filamentary material, for example triacetin, in the case of cellulose acetate. Other binders for the wick can be used, for example a hot-activatable binder, in particles, such as a thermoplastic in powder or in granules. If the filaments of the wick are themselves thermoplastic, an additional binder is not essential.

One or more flavoring products, for example menthol, can be deposited on the wick before it is compressed into a rod, preferably before depositing the adsorbent / binder mixture along the base already ^ section strip in channel and, preferably , before the strip is shaped along said channel section. Likewise, one or more particulate adsorbents (for example activated carbon, silica gel, etc.) can be sprayed onto the wick before deposition of the adsorbent / binder mixture, which provides a product in which the wick surrounds the continuous core. or discontinuous contains the dispersed particles.

Preferably, the wick containing the particle mixture deposited from the core is conveyed through the tubular former, being wrapped in a flexible permeable strip, the heating fluid passing through the permeable material of the enveloping strip to activate the activatable binder. hot for the filaments and the thermoplastic binder for the adsorbent particles. The preferred heating fluid is steam, especially when the wick is made of cellulose acetate and / or when the adsorbent particles comprise activated carbon.

It is preferable, in general, to convey the rod coming from the tubular former, in a cooling chamber; at this point, a cooling gas such as air can be sent transversely into the heated rod, preferably against the current with respect to the direction of advancement of the rod, allowing this rod to be formed into a coherent permeable product . The rod can be conveyed through such a cooling chamber, being wrapped in the same flexible permeable strip as that used to convey it through the tubular former. When such a flexible permeable strip is used, it is preferable to use an endless strip, flattening and separating from the finished rod, after leaving the tubular former (or the cooling chamber) to return to the inlet of said tubular former.

The completed continuous rod can be provided with a sealing envelope, in a traditional manner, this however not being essential, since the non-enveloped rod is generally coherent and stands by itself, so that it can be handled satisfactorily in the unwrapped state.

When the particulate mixture of the core is fed and deposited, in the form of a continuous line on the substrate formed by the wick, so as to obtain a rod with a core extending inside continuously, this mixture can be simply fed from a continuous metering device, mounted above said moving wick. When the particulate mixture of the core is to be deposited in the form of separate cells, spaced apart longitudinally therebetween, this is suitably obtained by means of an applicator wheel or drum having recesses spaced apart between them, on the periphery of its application surface, intended to receive the individual doses of said particulate mixture, for example coming from a hopper, the rotating applicator being arranged so that the recesses successively supply their contents on the wick. The applicator wheel is preferably arranged so that the branches of the channel section of the wick move on the side of the wheel which is at the location of the deposit, the additional cells being deposited on the base of the channel. The recesses are preferably elongated in the transverse direction.

A preforming of the wick, according to the channel shape required for the application of the particulate mixture of the core, is suitably carried out by passage through a horn. When the wick is shaped into a channel, with the use of a horn or similar device, it is preferable to provide, upstream of the horn, a former, for example made of metal wire, giving the circulating wick a trough shape. wide and shallow, open upwards, this being admitted into the horn and shaped like a channel, which is conveyed to the dosing hopper or the applicator wheel; thanks to this arrangement, better uniformity and better control of the shape and orientation of the feed from the wick to the applicator are obtained than by using only the horn.

When the cells of the particle mixture of the core are applied by means of a wheel or of a hollow applicator drum, the mixture can be ejected from its recess in the direction of the rod formed by the wick, by actuation of a pusher forming the base of the recess. Each recess can be provided, for example, with its own pusher or piston, the pusher or pistons being actuated, in a determined order, to empty their recesses, by cooperating with the surface of a fixed cam, as and when they move in rotation in front of the drop zone. The pistons or pushers are urged elastically in the direction of the axis of the wheel or of the drum, while being moved radially outwards against this urging 3j when they engage with the surface of the cam, to the depot area, then returning to their place in the recess, before receiving a new cell. The recesses are preferably filled continuously, for example from a hopper located at the top of their course, the pushers or pistons being actuated 40 to empty these recesses at the base, or near the base, of their course, means such as a protective sole being provided to prevent any premature spillage from the recesses, before actuation of said pushers or pistons. It may be advantageous for each piston or pusher to take, in the filling area, a retracted position providing a recess volume greater than the volume of mixture required subsequently and ejected from this recess in the direction of the rod, the piston or pusher then moving (preferably before leaving the filling area) radially outwards (for example under the action of a second cam profile), by a sufficient distance to allow scraping or eliminating any excess in relation to said required volume. This helps to ensure that each recess reaches the deposition area, enclosing a predetermined metered amount of the mixture. When moving 55 from the filling zone to the deposition zone, each piston or pusher can remain in its partially relaxed position, but will preferably take a more retracted position, so that the metered quantity of the mixture will not fill the recess .

The accompanying drawing shows, schematically and by way of example, several embodiments of the subject of the invention.

On this drawing :

fig. 1 is a schematic elevational view of an apparatus according to the invention;

fig. 2 is a perspective view showing, on a larger scale, parts of the apparatus of FIG. 1;

fig. 3 is a side view, in section, illustrating, on a larger scale, an applicator wheel which can be mounted on the apparatus of FIG. 1;

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fig. 4 is a perspective view of the base of a metering device used in the apparatus and the method according to FIGS. 1 and 2;

fig. 5 is a side view, in section, of a preferred embodiment of an applicator wheel and a horn for the passage of the wick;

fig. 6 is a partial sectional view along 6-6 of FIG. 5;

fig. 7 illustrates, in perspective, part of the apparatus according to an alternative embodiment.

In these figures, the corresponding elements are designated by the same reference numerals.

Referring to fig. 1 and 2, a wick 2 coming from a ball 1 of creped cellulose acetate is pulled, by rollers 3, through an air nozzle 4, forming a band, and passing over a guide cylinder 5 Rollers 6 rotating faster than rollers 3 stretch the portion of the wick between these rollers 6 and the rollers 3. Another air nozzle 7 transforms the wick into a strip of approximately 250 mm in width, before it passes into a box 10 where it is coated, by spraying, with glyceryl triacetate, by means of spray guns 8 and 9. The nozzles 4 and 7 are of known shape and include a narrow slot through which the wick passes. On one side of this slot, there is a perforated wall communicating with a compressed air supply, while on the other side of the slot, an unperforated wall maintains the wick while it is subjected to the air action. Rollers 11 hold the wick in the form of a strip, this shape being preserved until said wick passes under a former 12 and through the horn 15, or trumpet, which transforms it into a section in a loosely concentrated channel 55 , before it penetrates below a tongue 16. Between the trumpet 15 and the tongue 16 is mounted a continuous metering device 100, fed by the mixture 52 of particles for the core, coming from a hopper 54 The metering device 100 is in the form of a trough 102 of elongated V section, has an outlet slit along its base in the shape of a boat, said mixture of particles of the core being poured into the trough, at high speed. constant, by means of a conveyor 104. The latter is arranged near the outlet of the hopper 54, so that it conveys, from this outlet, the mixture 52 at constant speed. In the zone where the mixture of particles is brought into the trough 102, a suction is preferably applied to remove the fines, only the heavier particles being deposited in the trough and on the wick. The base of the trough 102 is disposed between the branches of the channel-shaped section 55 of the wick, which allows the core mixture to be deposited, continuously, at the base of this section, during its movement. The former 12 is profiled downward, so as to deform the strip so that it takes on a shape of shallow trough as it passes through the trumpet. This former is suitably only in the form of a bent metal wire. This preforming ensures the stability of the shape of the reduced section of the channel which is presented to the device 100 and the stability of its symmetrical arrangement relative to the device, at the location of the deposit. When using only a trumpet, the former 12 can be replaced by a simple roller. The trumpet 15 may have an extension 106 (not shown in FIG. 1) of section of the downstream channel, extending under the device 100, to support and guide said section in channel 55 of the wick.

The tongue 16 serves to guide the wick and the mixture deposited 52 in a heating enclosure 18, as well as to position a permeable strip 19 around the wick. The heating chamber 18, with the strip 19, constitutes a tubular former for reducing and shaping the wick and the mixture of the core, in the form of a filter rod provided with a sheath of tow surrounding the core. The permeable strip 19, which is pulled through the heating enclosure by means of the drum 20, and which also moves on rollers 21, 22, 23 and 24, is of open structure and can be made of woven or formed nylon polyethylene monofilaments

lneterephthalate. This strip may be coated on the surface with a silicone resin or with polytetrafluoroethylene, in order to prevent any adhesion of the wick. The heating enclosure 18 is provided with a duct 25 connected to a steam supply which circulates through passages provided in the enclosure and, therefore, through the strip and inside the wick and the core. , in order to heat them, which allows the glyceryl triacetate to bind the cellulose acetate filaments together, and the thermoplastic binder to agglomerate the adsorbent particles between them; there is, in general, also a certain bond between the nucleus and the filaments which surround it.

A rod 26 is thus formed. The longitudinal edges of the strip 19 cannot, however, join properly, so that several of the filaments of the wick press between these edges, thus forming a bead. The latter is eliminated by means of a presser foot 27, which is applied between the edges of the strip and presses said bead, so as to restore the stem to a substantially cylindrical shape. The rod then passes into a cooling enclosure 28, where air or other gas supplied by a conduit 30 circulates through the strip and comes into contact with the filaments and the core of the rod, in order to cool them and d remove any condensate from the rod 26. Preferably, the cooling air circulates through the strip at a multiplicity of points spaced along the length of the cooling enclosure 28. After passing through the rod, the air, at the same time as the condensate entrained, arrives in a receiver 17, provided with an exhaust towards the rear of the machine. The action of air also has the effect of imparting more rigidity to the rod. Leaving the cooling enclosure 28, the rod can pass directly to the cutting, but it can be first wrapped (for example in a paper wrapper, by passing through a conventional wrapping device), then sent to the cutting . In either case, the cutting device cuts the rod (wrapped or not) into distinct lengths.

As long as the strip passes around the drum 20 and the rollers 20 to 24, it has a flat shape. During its passage from the roller 24 to the drum 20, it is folded so as to take an incomplete cylindrical shape, with a slight space between its edges. Leaving the cooling chamber 28, the strip deploys and separates from the rod. The openings in the strip are of sufficient size to provide an easy passage for the steam and the air circulating in the rod and effecting the heat transfer. The finish of the surface of the rod 26 depends on the surface properties of the strip, on the fact that the filaments of the wick press against the strip while they are in a softened state under the influence of steam. When you want to get a deep embossed finish for the stem, you can use a coarse woven band. When you want a smoother rod, you can use a finely woven band. The embossing serves to prevent the separation of the fibers on the peripheral surface of the rod, without it being necessary, in general, to cause the coalescence of the peripheral fibers of the rod.

If desired, the arrangement may be such that the opening of the heating enclosure is slightly larger than the opening of the cooling enclosure. This last opening allows the rod to be adjusted to its desired final diameter.

Fig. 3 illustrates an applicator wheel 50 which can be mounted in place of the metering device 100 of FIGS. 1 and 2, for the purpose of depositing separate cells, spaced apart longitudinally, of the mixture 52 used for the core, on the basis of the channel 55 of the wick, in order to form a filter rod having a longitudinally discontinuous core of agglomerated particles adsorbent; each portion of the core of the entire unitary stem formed is surrounded by a sheath of bonded filaments, and separated, in the longitudinal direction, from the next portion by a plug of bonded filaments. The rod formed continuously, after wrapping if necessary, can be cut transversely into one or more5

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several stages (for example in lengths suitable for the manufacturer of the rod, then in shorter individual lengths at the time of incorporation in a filter cigarette), through the portions of the core and / or between these portions. With reference to fig. 3, the applicator wheel 50 has recesses 56, at a distance from each other on the periphery of its cylindrical surface, this wheel engaging downwards, as indicated, between the branches of the channel 55 of the wick assembled at the loose state, coming from the trumpet 15. The recesses 56 are fed by the hopper 54, in particulate mixture 52 for the core. A guard sole 57 prevents any spillage of the mixture 52 from these recesses 56, before depositing it in the body of the loose wick 55. The pockets or cells of the mixture in the recesses 56 are then transported by rotation of the wheel 50 and deposited individually in longitudinally spaced locations in the body of the wick, i.e., based on the wick channel. The recesses 56 are preferably elongated and have a section which is axially longer than on the periphery of the applicator wheel, so as to obtain separate core sections of desired configurations. The rest of the apparatus, namely the preparation and feeding mechanism, the tubular former and its auxiliary equipment and provided below, is as described above, with reference to FIG. 1.

Fig. 4 is a side perspective view, from the bottom and downstream, of the bottom of a preferred metering device which can be substituted for that shown in FIG. 2. Fig. 4 shows, in place of the trough 102 of elongated V section in FIG. 2, an elongated trough 200 having a vertical wall and an inclined longitudinal wall, the base of the trough (having the vertical longitudinal walls) being provided at its bottom with a longitudinal slot 204 through which the adsorbent / binder mixture is poured on the shaped strip of the wick, as in fig. 2. The upstream end 208 of the base of the trough 200 is in the form of a boat bow, as shown in FIG. 2. The downstream end 202, although slightly projecting downstream from the main body of the trough, ends in a flat face, as shown in FIG. 4. The slot 204 does not extend over the entire length of the trough 200, but stops very close to its upstream end, as shown in fig. 4. A boss, or keel, 206 projecting downward is preferably provided at the upstream end of the base of the trough, as shown. The spacing of the slot 204 from the upstream end of the trough and the presence of the keel 206 make it possible to control the passage of the strip of the wick and to maintain it in its required shape as a channel, thus reducing any tendency of this strip to go up in the slot.

The mixture 52 of particles for the core can have, in the embodiments described, any variety of compositions,

as already indicated, but will preferably contain particles or granules of activated charcoal mixed and coated with a relatively fine thermoplastic powder (for example of polyethylene). Whether the rod is formed with a continuous core (fig. 1 and fig. 2) or discontinuous (fig. 3), there is a connection not only between filaments in the portion of the wick, and between adsorbent particles in the core , but also a connection between the core and adjacent filaments, so that the rod can be cut through the core, without appreciable loss of the material of this core, during cutting or subsequent handling.

A preferred applicator wheel, which can be used like wheel 50, in the embodiment of FIG. 3 above, is shown by way of an example in Figs. 5 and 6. With reference to these figures, the applicator wheel 370 has recesses or holes 372 also spaced apart between them around the periphery of its cylindrical surface. The base of each recess 372 is formed by the free end of a plunger or piston 374. Each piston 374 is resiliently biased by a spring 376, radially towards the center 378 of the wheel, but is displaceable radially towards the outside, against this spring, so as to traverse the recess and thus eject its content. The operation, in a determined order, of the pistons and pushers, when the wheel is rotated in a clockwise direction, as shown in fig. 5, is carried out by means of a fixed cam profile 380 which cooperates with the ends extending radially inwards of the pistons or plungers over part of their path, as illustrated in said fig. 5. Used in the method according to the invention, the wheel 370 is mounted as shown and described with reference to FIG. 3, the recesses being filled with the additive coming from a hopper 371 when they pass in the vicinity of the top of their path, and the pistons or pushers being actuated by the cam profile 380, so as to empty the recesses in the area shown in fig. 5. A premature spillage of the additive from the recesses is prevented by a guard sole 382.

In their retracted position, the radially inner ends of the pistons 374 cooperate with the cylindrical lateral surface 384, while being kept in contact with this surface, by means of the springs 376.

According to a preferred embodiment, the depth of a recess 372, when the piston or pusher 374 is in its retracted position in abutment with the lateral surface 384, is greater than necessary for the recess to accommodate the volume d 'additive to be ejected into the wick, as an individual cell; on arrival at the hopper 371, each recess will therefore tend to be too full; however, there is provided, as shown, a second cam profile 383 intended to cooperate with the radially inner ends of the pistons or pushers 374, so that, just before each recess moves and is no longer in connection with the hopper, its pusher or piston moves radially outward over a short distance, the excess additive in this recess then being scraped so as to leave in said recess a predetermined charge for subsequent ejection into the wick. As shown, each piston is then preferably out of engagement with the cam profile 383, and moves again, under the action of the spring, towards its retracted position, in abutment with the lateral surface 384. In a typical example , when an additive thickness of 5 mm is required in each recess, the depth of the recess, with the piston or the plunger in the retracted position, is preferably 7 mm, the cam profile 383 being mounted so move the piston or plunger 2 mm radially outwards. The various cam profiles will preferably be adjustable according to the volume required for the additive cell.

Figs. 5 and 6 illustrate another preferred feature of the apparatus according to the invention, which can be used with the simplified application wheel of the type shown in FIG. 3, this feature being the use of a trumpet 15 provided with a channel section wick support 385, extending from the outlet of said trumpet up to and in front of the zone where the applicator wheel deposits the additive cells. This extension 385 supports the wick at the time of the additive deposition and allows the correct adjustment of the wick on one side or the other of said applicator wheel.

In fig. 5 and 6, the recesses 372 are shown with a circular section, but this is not essential. For the purposes sought in the invention, in the embodiments using an applicator wheel, or drum or the like, for depositing the additive cells from recesses or dimples, these recesses or dimples preferably have a section which is as long or longer, in the axis of the applicator, than on the periphery of the latter. The recesses or dimples are therefore preferably entirely symmetrical in section, for example circular or square, or have a section (for example elliptical or rectangular), the longest axis of which is directed transversely rather than longitudinally to the direction of movement of the applicator and the substrate in the deposition area. If the cross section of the dimple or recess is

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elongated shape, the longitudinal axis is preferably perpendicular to the direction of movement in the deposition area.

Fig. 7 illustrates, in perspective, the elements of another alternative embodiment according to the invention. In this figure, the same reference numerals from the previous figures are used to designate the corresponding elements. In fig. 7, the applicator wheel 370 is of the same type as in FIGS. 5 and 6, except that the trumpet 15 does not have an extension extending from its outlet collar to the deposition zone. The figure shows how the strip of the wick coming from the rollers 11 10 takes, through the former 12, the shape of a trough

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flat before entering the trumpet 15, which gives the loose link wick 55 a stable and symmetrical section in the form of a channel when it reaches the applicator zone of the wheel 370. The former 12 into a metal wire is shown in an orientation different from that indicated in fig. 3, because it is adjustable at will to adjust the shape of the wick 55 leaving the trumpet 15. The wick in the form of a channel 55, having the additive cells deposited along its base, is routed, after passage in front of the applicator wheel 370, towards the device for shaping the rod (not shown), as described in the other embodiments.

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Claims (13)

619847 1. Tobacco smoke filter rod, characterized in that it comprises a smoke-permeable body, formed of continuous filaments (2) linked together at points of contact and surrounding a smoke-permeable core, formed of adsorbent particles (52) agglomerated together by means of a thermoplastic binder, this core extending at least partially over the length of the rod. 2. Smoke filter rod according to claim 1, characterized in that the core is in the form of a plurality of cells spaced longitudinally between them. 2 3. Filter rod according to one of claims 1 or 2, characterized in that the body of continuous filaments contains at least one flavoring agent and / or one adsorbent in particles. 4. Filter rod according to one of claims 1 to 3, characterized in that the core is linked to the filaments which surround it. 5. A method of manufacturing a smoke filter rod according to claim 1, characterized in that one conveys continuously, longitudinally, in the form (12) of a strip with channel section (55), a wick (2) formed of a continuous filament material, filtering smoke, containing (10) a heat-activatable agglomerating agent for the filaments, is deposited (102) continuously, along the base of the channel section (55 ), a bead in the form of a continuous line or of separate cells spaced apart longitudinally, of a mixture (52) in particles of an adsorbing agent and of a thermoplastic binder, the wick is compressed and the mixture particles deposited, by continuous passage through a tubular former (18), a hot fluid is circulated through the wall of the former, in order to impregnate and heat the rod and activate said hot-activatable agglomerating agent and said thermoplastic binder, in order to form a continuous filter rod of filaments linked together, pre sensing a core of agglomerated adsorbent particles extending continuously through this rod, or a core formed of separate cells spaced apart longitudinally. 6. Method according to claim 5, characterized in that the wick containing the particle mixture deposited from the core is conveyed through the tubular former (18), being wrapped in a flexible permeable strip (19), the heating fluid passing through the permeable material of the enveloping strip (19). 7. Method according to one of claims 5 or 6, characterized in that the heating fluid is steam. 8. Method according to one of claims 5 to 7, characterized in that the rod moves, after the tubular former (18), through a cooling chamber (28) where a cooling gas is sent transversely into the rod hot (26). 9. Apparatus for implementing the method according to claim 5 for the manufacture of a smoke filter rod, characterized in that it comprises means (4-10) for continuously routing a wick (2) in strip of material formed from continuous filaments filtering the smoke, containing (10) a hot-activatable binder for the filaments, forming means (12) continuously conferring on the moving strip a channel-shaped section (55), a metering device (100) continuously depositing along the base of the channel (55) a continuous line or separate cells longitudinally spaced from a mixture (52) of adsorbent particles and the thermoplastic binder, and immediately downstream of the metering device (100), a tubular former (18) intended to condense, in the form of a rod (26), the wick (2) and the mixture (52) deposited of particles, means (25) for sending a fluid laterally heating in this rod as it progresses through said former t ubular (18), as well as means for transversely cutting the resulting rod produced continuously, into sections of determined lengths. 10. Apparatus according to claim 9, characterized in that the metering device (100) comprises an applicator wheel (50, 370) having spaced recesses (56, 372) on its peripheral application surface, intended to receive the individual doses of mixture (52) in particles, means (54-371) for continuously loading the mixture (52) in particles in these recesses (56, 372), and a guard sole (57-382) intended to prevent premature spillage of this mixture (52) from these recesses (56-372) during their movement towards the deposition zone, the applicator wheel (50, 370) being rotatably mounted and arranged so that, when actuated, the recesses (56, 372) apply their contents to the wick (55), in the form of separate cells spaced apart longitudinally. 11. Apparatus according to claim 10, characterized in that the base of each recess (372) in the wheel (370) is formed by a pusher (374), a fixed cam profile (380) being arranged to cooperate with the pusher (374) and actuate them in a determined order, so as to empty the recesses (372) and eject their content of mixture of particles in the deposition zone. 12. Apparatus according to claim 11, characterized in that it has means (383) for actuating the pushers allowing each pushbutton (374) to take, in the filling area, a retracted position providing a volume of hollow- ment (372) larger than the volume of particle mixture subsequently required to be ejected from the recess (372) onto the wick (55), and moves radially outward, a distance sufficient to scrape or discharge any excess particles greater than the required volume. 13. Apparatus according to one of claims 10 to 12, characterized in that the recesses (372) of the wheel (370) are of circular or square section, in radial directions of the applicator area (370) and have a section elongated transverse axis, the major axis of which extends transversely to the direction of movement of the applicator wheel (370) in the deposition zone.