WO2014147057A2

WO2014147057A2 - Apparatus and method for filling cavities with particulate material

Info

Publication number: WO2014147057A2
Application number: PCT/EP2014/055381
Authority: WO
Inventors: Diego Ferrazzin; Marco Bonaveri; Niki MELONCELLI; Ilario LODI; Gastone MINNELLI; Alessandro BEGHIN
Original assignee: Philip Morris Products S.A.
Priority date: 2013-03-19
Filing date: 2014-03-18
Publication date: 2014-09-25
Also published as: RU2640459C2; JP6065298B2; ES2688455T3; JP2016509856A; CN105188423A; EP2975950B1; EP2975950A2; BR112015018821B1; RU2015144664A; WO2014147057A3; CN105188423B; BR112015018821A2; KR20150129686A; KR101853173B1

Abstract

The apparatus for filling cavities with particulate material comprises a conveyor belt comprising an orifice. The orifice is adapted for accommodating particulate material and for dispensing the particulate material through the orifice. The apparatus further comprises a first and a second guiding wheel for transporting and guiding the conveyor belt. The first and second guiding wheels are arranged at a distance to each other and such that the conveyor belt comprises a straight belt portion arranged between the first and the second guiding wheel. A retention element is arranged adjacent the lower side of the conveyor belt for keeping the orifice closed before the orifice reaches a transfer location at the first guiding wheel. The retention element and the straight belt portion are further arranged to allow particulate material in the orifice to be dispensed through the open orifice at the transfer location, wherein the particulate material is transferred to the conveyor belt through the first guiding wheel.

Description

Apparatus and method for filling cavities with particulate material

The present invention relates to apparatuses and methods for filling cavities with particulate material. In particular, the invention relates to such an apparatus and such methods for use in the manufacture of filter elements for smoking articles.

In the manufacture of filter elements for smoking articles cavities between filter plugs may be filled with particulate material such as for example activated carbon. Typically, in order to perform a controlled filling of the cavities, suction is applied to the cavity through the wrapping paper. However, this method is not suitable when using wrapping material with a low gas permeability such as plastic foil.

Therefore, there is a need for an apparatus and method that enables a reliable filling of cavities. In particular, there is a need for such apparatuses and methods where wrapping material with a low gas permeability are used for wrapping a cavity.

According to an aspect of the invention there is provided an apparatus for filling cavities with particulate material. The apparatus comprises a conveyor belt comprising an orifice. The orifice is adapted for accommodating particulate material and for dispensing the particulate material through the conveyor belt. The apparatus further comprises a first guiding element and a second guiding element in the form of a first guiding wheel and a second guiding wheel for transporting and guiding the conveyor belt. The first guiding wheel and the second guiding wheel are arranged at a distance to each other and such that the conveyor belt comprises a straight belt portion arranged between the first guiding wheel and the second guiding wheel. Yet further a retention element is arranged adjacent the lower side of the conveyor belt for keeping the orifice closed before the orifice reaches a transfer location at the first guiding wheel. The retention element and the straight belt portion are further arranged to allow particulate material in the orifice to be dispensed by gravitational force at the transfer location and preferably while the orifice is in the straight belt portion. When the conveyor belt passes the retention element, the retention element keeps a lower opening of the orifice closed. Thereby the orifice forms a pocket, where particulate material may be supplied to and retained until the retention element deblocks the lower opening of the orifice and the particulate material may be dispensed from the orifice. In the apparatus according to the invention the particulate material is transferred to the conveyor belt through the first guiding wheel.

Preferably, the straight belt portion begins in a downstream direction at the transfer location. The particulate material may be dispensed into a cavity arranged adjacent the orifice in the transfer location. Preferably, the cavity is guided in parallel to and at substantially the same speed as the orifice along the straight belt portion. However, depending on the size of the cavity and the orifice, the speed of the cavity and the speed of orifice may differ, resulting in a relative speed between the orifice and the cavity. This may be advantageous where the cavities are substantially longer than an outer size of the orifice.

Providing orifices in a conveyor belt for dispensing particular material into a cavity arranged adjacent to the orifice facilitates a filling of the cavity. The time the transfer of particulate material from the orifice into the cavity takes place may thus be extended. This is especially effective when operating an apparatus at high speed, such as the semi-continuous filling of cavities at high speed, for example of cavities in a stream of rod-shaped elements. Also the dispensing of the particulate material from the orifice may be subject to passive forces, such as the gravitational force, additionally supported by overall vibrations of the apparatus. In known methods, a transfer of particulate material from an orifice to a cavity is limited to a transfer location. In devices known in the art, material transfer can happen only at the single transfer location where the orifice and a cavity for receiving the particulate material coincide in time and space. According to the invention particulate material may be dispensed out of an orifice not only at the transfer location but also along a straight belt portion. Such, the time where transfer of particulate material takes place may be adapted, for example to particulate material properties, constructional requirements or the like.

Active transfer means such as suction or gas streams at the transfer location may be omitted. Thus, a construction of the apparatus may be simplified. Also, the likelihood of particulate material being blown away is reduced. Further, the cavity filling method may especially be applied also when using wrapping material with a low gas permeability for enclosing or forming the cavity. With respect to using wrapping material with a low gas permeability for enclosing or forming the cavity, no suction for an immediate transfer of particulate material to the cavity at the transfer location is required, since the filling process is not limited to the transfer location. Therefore, the method according to the invention is especially suitable, although not limited to wrapping material with a low gas permeability forming or partly forming a cavity.

In the present invention, the filling of the cavity, that is, the transfer of the particulate material from the orifice into the cavity may take place substantially by gravitational force only, since the duration of the transfer process of the particulate material into the cavity is extended.

Preferably, the straight belt portion is arranged horizontally. By this, gravitational force acting on the particulate material in the orifice may be used for emptying the orifice to a maximal extent. However, the straight belt portion may also be arranged in positions diverging from the exact horizontal position thereby still making use of the gravitational force for particulate material to be dispensed from the orifice. For example the straight belt portion may have a tilted position with regard to a horizontal axis. For example, a forward tilt angle or backward tilt angle may be up to 15 degrees.

Transferring particulate material to the conveyor belt through the first guiding wheel enables an easy and swift filling of an orifice in the conveyor belt, for example while guiding the conveyor belt along the first guiding wheel. Especially, it allows to fill the orifice through its opening arranged on one side of the conveyor belt and to discharge the particulate material through the opening arranged on the opposite side of the conveyor belt. An orifice may thus be optimized for a filling and for an emptying of the cavity. For example, an orifice may be asymmetrical in view of filling and emptying. For example, an orifice may be provided with a larger filling opening and a smaller discharge opening, for example an opening may be funnel-shaped. For example, the filling opening may be large to facilitate filling of the orifice and the discharge opening of the orifice may be adapted to the size of a cavity the particulate material is to be discharged into to allow a precise transfer of particulate material into the cavity. A discharge opening may for example have the same size as the cavity or may be smaller than the cavity. By filling the orifice though the first guiding wheel also the distance particulate material travels in the conveyor belt, and by this also an overall travelling distance of particulate material may be kept at a minimum. By this, potential loss of material or soiling of the apparatus or of an entire installation may be kept at a minimum. Transferring particulate material to the conveyor belt through the first guiding wheel may for example be realized in the form of a supply chamber arranged in the first guiding wheel. It may for example also be realised by a supply channel, such as a supply tube, guided into the first guiding wheel such that particulate material may be transferred to the conveyor belt through the first guiding wheel.

Preferably, the conveyor belt is a closed-loop endless belt arranged around the first guiding wheel and the second guiding wheel. In using a closed- loop endless belt, the guiding of the conveyor belt and the filling and emptying of orifices may be performed in an endless manner and in a closed-loop system. This advantageously simplifies the set-up of the apparatus according to the invention. For example, when using an endless belt only one guiding wheel has to be adapted to be a driving wheel, while any further guiding wheels may be driven wheels.

One or several orifices may be arranged in a conveyor belt according to the invention. Preferably, a plurality of orifices is arranged in the conveyor belt. A distance between neighbouring orifices preferably corresponds to a distance between neighbouring cavities. The cavities are preferably provided in a stream of rod-shaped elements, for example filter elements such as filter plugs.

In the apparatus according to the invention, preferably the size of the orifice corresponds to an amount of particulate material to be dispensed into a cavity. However, the size of an orifice may also contain a small amount of particulate material, substantially less than what would be required for completely filling a cavity. The particulate material in the orifice may then rather be an amount of particulate material for a filling of for example the last 10 to 30 percent of the cavity. In order to get a completely filled cavity, for example dispensing a particulate material from the orifice into the cavity may be started while particulate material is still supplied to the orifice.

Preferably, the shape of an orifice is that of a funnel having an upper opening, which is larger than a lower opening, where the upper opening has the function of filling opening and the lower opening has the function of discharge opening. The shape and size of the lower opening of the funnel or of an otherwise shaped orifice, defines a flow of particulate material out of the orifice. Such lower opening may for example be of circular or oval shape and have sloped edges to facilitate a dispensing of particulate material out of the orifice and into the cavity. While a generally circular or oval shape of the lower opening of the orifice may be preferred, as such an opening is relatively easy to manufacture, other shapes may be readily envisioned, for example rectangular or triangular. Different shapes may be advantageous depending on the size and shape of the particulate material handled by an apparatus according to the invention.

According to the invention, particulate material refers to discrete particles or to small objects as individual items, such as bulk material, powder, granules, capsules and mixtures thereof or like objects that may be handled by the apparatus and method according to the invention. Preferably, the particulate material is made of granules or of small objects which are substantially spherical objects. Preferably, granules or small objects have a diameter or extensions of between about 0.2 mm and about 1 .5 mm, more preferably between about 0.3 mm and about 0.8 mm. Preferably, the substantially spherical object is a capsule. Preferably, the capsule comprises a particulate material or a liquid. Preferably, the liquid is a flavorant and particulate material is activated carbon granules. Preferably, the capsule is crushable or thermally instable, that is, the capsule can release its content when a sufficient crushing strength, sufficient heat or other sufficient means of release is applied.

Preferably, the particulate material comprises activated carbon and flavour capsules such as, for example, Viscopearls™ available from Rengo,

Japan. Preferably, the particulate material comprises between about 30 percent and about 70 percent of activated carbon and between about 70 percent and about 30 percent flavour capsules.

According to an aspect of the apparatus according to the invention, the apparatus further comprises a pusher element arranged next to an upper side of the straight belt portion. The pusher element comprises a cam for being inserted into the orifice of the conveyor belt for pushing particulate material out of the orifice and into the direction of a cavity. A pusher element may support a complete emptying of an orifice and thereby further support the filling of a cavity with a defined amount of particulate material. A cam inserted into an orifice acts locally without further influencing for example particulate material already present in the cavity arranged adjacent to the orifice. Preferably, the size of a cam and its insertion depth into an orifice is chosen such as not to touch an orifice wall or the belt, respectively. This may advantageously prevent or limit squeezing or rupturing the particulate material. Preferably, a distance between cam and orifice walls or belt is larger than a diameter or the average extension of the particles of the particulate material. In addition, the distance between the cam and the orifice will ensure little wear from either part. Further, the distance may prevent spillage of the particulate material from the upper end of the cavity into or onto the belt or other parts of the apparatus.

According to another aspect of the apparatus according to the invention, the first guiding wheel comprises a supply chamber for holding an amount of particulate material. The supply chamber is arranged inside the first guiding wheel and is provided with a supply opening in a supply periphery of the supply chamber. This supply periphery corresponds to a peripheral portion of the first guiding wheel. The supply opening is provided for supplying particulate material from the supply chamber through the supply opening to the orifice in the conveyor belt, when the orifice is arranged at the peripheral portion of the first guiding wheel at a position corresponding to the position of the supply opening. By the provision of a supply chamber in the first guiding wheel, a supply of particulate material is integrated into the first guiding wheel thus additional machine parts and space may be saved. Since the conveyor belt is guided by and thereby in contact with the guiding wheel, such a peripheral contact region may be used and adapted to the transfer of particulate material from the supply chamber to the orifice in the conveyor belt. A supply periphery of the supply chamber and the peripheral portion of the first guiding wheel is a circumferential portion of the first guiding wheel. Preferably, an inner part of the first guiding wheel comprising the supply chamber is a stationary part of the first guiding wheel. Preferably, an outer part of the first guiding wheel guiding the conveyor belt is a moving part of the first guiding wheel. The moving part of the first guiding wheel preferably comprises at least one supply opening, which is moved along part of the circumference of the first guiding wheel such that the at least one supply opening coincides with an orifice in the conveyor belt.

In some embodiments of the apparatus according to the invention, a supply chamber, which may be a separate supply chamber or may be integrated into for example a first guiding wheel as described above, comprises circulation means for affecting a circulation of the particulate material in the supply chamber. Circulation means may prevent a clustering of particulate material in the supply chamber or a blockage of particulate material. The circulation means may also provide the particulate material with a specific moving direction or speed into said specific moving direction. A specific moving direction is preferably directing towards to the location of the supply opening. The moving direction and speed may also be adapted to the speed of an orifice passing the supply chamber, into which orifice the material shall be filled into from the supply chamber. By this a speed difference between the particulate material and the orifice may be reduced at the supply location, that is, at the location where particulate material is supplied from the supply chamber to the orifice in the conveyor belt. Circulation means may provide one or a combination of the above mentioned features and thereby support a filling of the orifice.

Circulation means may be active or passive circulation means. Active circulation means actively act on the particulate material, for example in the form of agitating means such as a gas stream, vibrating means or doffers. Passive circulation means passively affect the moving direction of the particulate material by their presence, for example in the form of obstacles arranged in the supply chamber such as wall elements or protrusions in supply chamber walls. Preferably, wall elements guide particulate material into the direction of a supply opening in the supply chamber.

According to another aspect of the apparatus according to the invention, the apparatus further comprises an apparatus cleaning unit for removing particulate material from the first or from the second guiding wheel. Preferably, the apparatus cleaning unit comprises a cleaning element that is arranged downstream of the transfer location at the first guiding wheel. An apparatus cleaning unit removes particulate material that has not been transferred into a cavity. This may for example be done by means of suction or a gas stream. The apparatus cleaning unit removes such stray particulate material from a guiding wheel, especially from the peripheral portion of the guiding wheel, where the guiding wheel has been or comes into contact with the conveyor belt. Stray particulate material is not desired because it may soil the apparatus. It may also lead to the blocking of a driven guiding wheel and to the rupture of the conveyor belt. Further, it may affect the optical and physical appearance of a final product, such as a filter cigarette.

Preferably, an apparatus cleaning unit is arranged next to the first guiding wheel, adjacent downstream of the transfer location. An apparatus cleaning unit may also be adapted to clean the conveyor belt, either together or separate to the cleaning of a guiding wheel. Preferably, the apparatus cleaning unit is arranged such that a cleaning action by the apparatus cleaning unit does not affect the particulate material in a filled cavity, for example to prevent that particulate material is inadvertently removed from the cavity.

According to a further aspect of the apparatus according to the invention, the apparatus further comprises a rod cleaning unit arranged downstream of the second guiding wheel. Preferably, the rod cleaning unit is adapted for removing stray particulate material from an area next to a cavity. The cavity, which preferably has prior been filled with particulate material, is provided in a stream of rod-shaped elements and is arranged next to a longitudinal end of a rod-shaped element of the stream of rod-shaped elements.

With the provision of a rod cleaning unit, the presence of stray particulate material in a final product may be reduced or eliminated. The cleaning action of the rod-cleaning unit is directed to the part of the stream of rod-shaped elements, for example, filter plugs, which are adjacent to the cavity and defining the size of the cavity in the non-final product the cavity or cavities are arranged in. Preferably, the rod-cleaning unit is directed and focussed to the area next to the cavity. The cleaning action may be directed to the rod-shaped element arranged next to the cavity such as to remove stray particulate material from the outside of the rod- shaped element but not from the cavity arranged next to the rod-shaped element. Typically, for example, so called "plug-space-plug" filters that comprise a cavity are arranged such that cylindrical acetate tow plugs are distanced from each other and commonly wrapped by sheet like wrap material such as, for example, a web of porous plug wrap. The empty space or cavity between the filter plugs may be filled by other items, such as, for example, particulate material. Preferably, the rod cleaning unit is adapted to remove stray particulate material from an area in between two neighbouring cavities. The neighbouring cavities are arranged next to two longitudinal ends of a rod-shaped element of the stream of rod-shaped elements. A cavity may additionally be protected by a shield element while performing the cleaning action next to the cavity.

An apparatus cleaning unit may also be combined with a rod cleaning unit such that for example suction or a gas stream used in the apparatus cleaning unit may be used for cleaning portions of the stream of rod-shaped elements and of one of the first guiding wheel or second guiding wheel. By this, only one supply and outlet for providing suction or a gas stream are then required.

According to another aspect of the apparatus according to the invention, the first guiding wheel and the second guiding wheel is a first toothed wheel and a second toothed wheel and the conveyor belt is a toothed belt arranged along a circumference of the first toothed wheel and of the second toothed wheel. Using toothed wheels in combination with a toothed conveyor belt is a precise and reliably way of transporting and guiding the conveyor belt and thus positioning and guiding of the orifices that are filled with particulate material to dispense the particulate material into cavities. Generally, only one of the first guiding wheel and the second guiding wheel is a driven guiding wheel. Therefore, only the driven guiding wheel needs to be provided with teeth for engaging the teeth of the conveyor belt. However, a more precise and smooth guiding of the conveyor belt may be achieved by providing the first guiding wheel and the second guiding wheel with teeth.

In some embodiments the orifice in the conveyor belt is arranged between two sets of teeth, which sets of teeth are arranged in parallel along lateral sides of the conveyor belt. Accordingly, at least one of the first guiding wheel and the second guiding wheel, is also provided with two sets of teeth, which are arranged in parallel along lateral sides of the at least one of the first guiding wheel or the second guiding wheel. If a guiding wheel is realized as toothed wheel, the toothed wheel may be provided with two sets of circumferential arranged teeth.

According to a further aspect of the apparatus according to the invention, the apparatus comprises an ionization unit for electrostatically discharging particulate material. Some kinds of particulate material, for example, particulate material made of plastic material or comprising outer surfaces made of plastic material, tend to get electrostatically charged upon handling of these particulate materials, particularly through friction. This may have the effect that the particulate material may tend to separate from each other and adhere to neutral or opposedly charged surfaces such as, for example the supply chamber, the guiding wheels or other parts of the machinery. Further, the electrostatic charge may prevent or hinder the particulate material from entering into the orifice or the cavity. By electrostatically discharging the particulate material a filling of orifices and cavities or removal of stray particulate material from unintended locations within the filling machinery may be facilitated. An electrostatic discharging of particulate materials may for example be achieved by application of an ionized gas stream to the particulate material, to parts of the apparatus or to, for example, a stream of rod- shaped elements with empty, partially empty and full cavities.

According to another aspect of the invention, there is provided a method for filling cavities with particulate material. The method comprises the step of providing a conveyor belt comprising an orifice. The method further comprises the step of transporting and guiding the conveyor belt by a first guiding wheel and a second guiding wheel. According to the method of the invention the first guiding wheel and the second guiding wheels are arranged at a distance to each other such that the conveyor belt forms a straight belt portion between the first guiding wheel and the second guiding wheel. In a further step the orifice is filled through the first guiding wheel with particulate material while the orifice is kept closed. Preferably, a discharge opening of the orifice is kept close or an orifice may be kept close except for a filling opening of the orifice. A cavity in a stream of rod- shaped elements is arranged adjacent to the orifice at a transfer location. A further step comprises dispensing the particulate material through the open orifice into the cavity arranged adjacent to the orifice, for example, by gravitational force, while guiding in parallel the orifice in the conveyor belt and the cavity in the stream of rod-shaped elements along the straight belt portion. The open orifice may be the orifice, where for example a retention element previously closing the orifice or closing a discharge opening of the orifice is absent for particulate material to now be discharged from the open orifice.

According to an aspect of the method according to the invention, the method further comprises the step of inserting a cam into the orifice, thereby pushing particulate material into the direction of the cavity.

According to another aspect of the method according to the invention, the method further comprises the steps of providing particulate material in a supply chamber arranged in the first guiding wheel, guiding the orifice along the first guiding wheel such as to pass a supply opening in the supply chamber and supplying particulate material from the supply chamber through the supply opening to the orifice in the conveyor belt.

According to a further aspect of the method according to the invention, the method further comprises the step of affecting a circulation of the particulate material in the supply chamber.

According to yet another aspect of the method according to the invention, the method further comprises the step of removing stray particulate material from the stream of rod-shaped elements by applying suction or by directing a gas stream to a rod-shaped element of the stream of rod-shaped elements. Preferably, the gas stream or suction is applied to one rod-shaped element at a time and preferably in a focussed manner to prevent inadvertent removal of particulate material from a cavity arranged next to the rod-shaped element where suction or a gas stream is directed to. Preferably, the step of removing stray particulate material is performed after filling a cavity and more preferably before a stream of rod-shaped elements is further processed. A further processing may for example be the closing of the cavities such as for example an entirely wrapping and closing a filter paper around a stream of filter elements.

The advantages of the different aspects of the method have been described above relating to the aspects of the apparatus according to the invention and will therefore not be repeated.

In some embodiments of the method, rod-shaped elements comprising gas-permeable material are provided and suction is applied to a rod-shaped element comprising gas-permeable material. The suction is such that it may act through the gas-permeable material and onto the cavity arranged next to the rod- shaped element comprising gas-permeable material. By this, a filling of the cavity with particulate material may be supported by drawing particulate material into the cavity and towards the side walls of the cavity in a substantially longitudinal direction, that is, parallel to the transport direction of the filter elements. By applying suction to the gas-permeable material, no particulate material is drawn out of the cavity. This aspect of the method is especially suitable if a cavity is partly formed of or located in a wrapping material with a low gas permeability, such as for example a gas-tight wrapping foil. Preferably, the rod-shaped elements are filter elements and the gas-permeable material is filter tow such as acetate. By this, suction may be applied to a cavity, even if this may not be done through an outer wrapping material due to low gas permeability of this wrapping material. However, suction may be applied along a transportation direction of the cavity, for example in the stream of filter elements. While this cleaning method of the stream of filter elements with particulate material located in cavities has been described in conjunction with the use of a continuous belt, it will be appreciated, that this cleaning method could also be employed with an apparatus that provides the particulate material to the cavities, for example with a wheel directly into the cavity at a limited transfer location. According to an aspect of the invention the apparatus and method according to the invention are used in the manufacture of filter elements for smoking articles.

The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein

Fig. 1 shows a cross sectional front view of an embodiment of the apparatus according to the invention for use in the production of a filter element;

Fig. 2 shows a front view - partly broken - of a toothed wheel including supply chamber for particulate material ;

Fig. 3 shows a cross section of an orifice in a conveyor belt aligned with a cavity;

Fig. 4 shows a cross-section of a cam of a pusher element inserted into an orifice;

Figs. 5-8 are enlarged views of the cleaning region of a rod cleaning unit comprising a cleaning wheel in a cross sectional side view of the cleaning wheel (Fig.5 and Fig.7) and a front view of the cleaning wheel (Fig.6 and Fig.8) in an open, rod-cleaning state (Fig.5 and Fig.6) and in a closed, non-rod-cleaning state (Fig.7 and Fig.8). In Fig. 1 an embodiment of the apparatus for filling cavities according to the invention is shown. A closed-looped conveyor belt 1 is arranged around a first and a second guiding wheel in the form of a first and a second toothed guiding wheel 2,3. First and second toothed guiding wheels 2,3 are arranged next and distanced to each other such that the conveyor belt 1 forms a horizontal straight belt portion 12 between first and second guiding wheel 2,3. Conveyor belt 1 comprises a plurality of regularly arranged orifices 10. Orifices 10 are filled with particulate material from a supply chamber 20 in the first guiding wheel 2 and the particulate material is dispensed from orifices 10 into cavities 51 in a stream of rod-shaped elements 5 arranged below the straight belt portion 12.

A retention element 15 is shown on the right hand side of Fig. 1 . Retention element 15 is arranged along a portion of the lower side 1 1 of conveyor belt 1 closing off orifice 10 on a lower side. Along this portion orifice 10 forms a pocket for receiving the particulate material. The length of retention element 15, that is the length of the portion of the lower side of conveyor belt 1 that is covered by retention element 15, is chosen to keep orifice 10 closed from a position shortly prior to the filling of the orifice. At a transfer location 100, the particulate material is dispensed from orifice 10. Supply chamber 20 extends along the periphery of first guiding wheel 2 from about a 3 o'clock position of first guiding wheel 2 to shortly before transfer location 100, which transfer location is arranged at a 6 o'clock position of first guiding wheel 2.

The stream 5 of rod-shaped elements 50, for example filter plugs for smoking articles such as cigarettes, is arranged horizontally below the straight belt portion 12 and guided in parallel to the straight belt portion 12. The stream of rod- shaped elements 5 is provided with cavities 51 in between rod-shaped elements 50. Stream of rod-shapes elements 5 and conveyor belt 1 are synchronized such that orifice 10 in conveyor belt 1 and cavity 51 in the stream of rod-shaped elements 5 meet at transfer location 100 at first guiding wheel 2. Conveyor belt 1 and stream of rod-shaped elements 5 are further synchronized such as to have the same or a similar speed such that cavity 51 , arranged below and adjacent to orifice 10, is guided parallel and together with orifice 10 along straight belt portion 12.

A first apparatus cleaning unit 60 for cleaning first guiding wheel 2 is arranged downstream of transfer location 100 and next to first guiding wheel 2 seen in clockwise direction of first guiding wheel 2. First apparatus cleaning unit 60 comprises a cleaning chamber 601 where suction or a gas stream is applied for removing stray particulate material from the circumferential region of first guiding wheel 2, which particulate material has not been transferred to orifices 10 in conveyor belt 1 but clings to first guiding wheel 2. The lower part of the first apparatus cleaning unit 60 is formed as to support and guide the conveyor belt 1 in the horizontal portion. Also, it prevents spillage of the particulate material from the belt during the downstream movement.

A second apparatus cleaning unit 62 for cleaning second guiding wheel 3 is arranged downstream and next to second guiding wheel 3. The second apparatus cleaning unit 62 is combined with a rod cleaning unit 61 for cleaning stray particulate material from the rod-shaped elements 50 of the stream of rod-shaped elements.

Second apparatus cleaning unit 62 removes stray particulate material from second guiding wheel 2 as well as from conveyor belt 1 being in contact with second guiding wheel 3 from about a 6 o'clock to a 9 o'clock position at second guiding wheel 3. Also the removal of stray particulate material from second guiding wheel 3 is preferably performed by suction or a gas stream.

Downstream of the location where the straight belt portion 12 has ended at the 6Ό clock position of second guiding wheel 3, the stream of rod-shapes elements 5 moves further in a horizontal transportation direction to the left in Fig. 1 and thereby passes rod-cleaning unit 61 for cleaning the rod-shaped elements in the stream of rod-shaped elements 5. The straight belt portion 12 starts at transfer location 100 and ends at the 6 o'clock position of second guiding wheel 3. During the time orifice 10 and corresponding cavity 51 pass straight belt portion 12, particulate material is enabled to be dispensed from orifice 10 to cavity 51 .

At the straight belt portion 12, a pusher element 4 in the form of a toothed pusher wheel is arranged above conveyor belt 1 next to the upper side of conveyor belt 1 . Pusher element 4 comprises four cams 42 regularly arranged around and extending from the circumference of pusher wheel 4. Cams 42 are arranged and synchronized with conveyor belt 1 such that cams 42 may interact with orifices 10 of conveyor belt 1 as shown and described in more detail in Fig. 4.

In the apparatus as shown in Fig.1 conveyor belt 1 is guided in a clock-wise direction such that orifices 10 are transported from supply chamber 20 in first guiding wheel 2, where they are filled with particulate material, to transfer location

100 and along straight belt portion 12, where the particulate material is dispensed from orifices 10 to cavities 51 . Thereby, they pass first apparatus cleaning unit 60 and pusher wheel 4. When reaching second guiding wheel 3, conveyor belt 1 is received by teeth 30 on second guiding wheel 3 and made to pass second apparatus cleaning unit 62. Further in clockwise direction, the now cleaned conveyor belt is transported back to first guiding wheel 2, thereby passing a belt cleaning unit 80 and a tensioning element 70 for a further tensioning and guiding of conveyor belt 1 . The stream of rod-shaped elements 5 moves further in a horizontal transportation direction to the left, thereby passing rod-cleaning unit 61 .

The distance between the location where particulate material is filled into the orifices 10 in the conveyor belt 1 and the transfer location 100 where the particulate material is dispensed from the orifices 10 into the cavities 51 of the stream of rod-shaped elements 5 is about the length of a quadrant of the first guiding wheel 2. This provides enough time for the orifices to be reliably filled with particulate material. In addition, presence of particulate material in the conveyor belt is limited to this distance. This limits the area where particulate material might get lost or might soil the apparatus or both. It may be seen that this distance may further be limited by reducing the distance between the location where particulate material is filled into the cavities and the transfer location.

Fig. 2 shows first guiding wheel 2 with supply chamber 20 extending in the lower right side half of first guiding wheel 2 with an intended clockwise rotational direction of a rotatable outer part of first guiding wheel 2. Stationary supply chamber 20 receives particulate material through a supply tube 22 (indicated in dash-dotted lines) from a reservoir 71 (see Fig. 1 ). Supply chamber 20 is provided with two gas supply openings 201 and corresponding gas supply connectors 202 for connection to a gas supply, such as for example a pressurized gas source. The gas supply openings are provided in an upper and a lower part of supply chamber 20. Lower gas supply opening 201 is arranged such as to provide a gas stream to the circumference of supply chamber 20 removing particulate material from the circumferential side wall of the supply chamber and keeping particulate material circulating in supply chamber 20. Upper gas supply opening 201 is arranged such as to also direct a gas stream into the circumferential direction of supply chamber

20. By this, particulate material in supply chamber 20 is given a speed and direction along the circumference of supply chamber 20 thereby adapting the speed of the particulate material moving along the circumference to the speed of the orifices in conveyor belt 1 . Conveyor belt (not shown in Fig.2) is guided along part of the circumference of first guiding wheel 2, the teeth 1 1 of conveyor belt 1 thereby interacting with teeth 21 on first guiding wheel 2. The teeth of first guiding wheel 2 belong to a rotatable part of the first guiding wheel 2. Preferably, the teeth 1 1 are arranged circumferentially on both lateral sides of first guiding wheel 2. In between these two sets of circumferentially arranged teeth 1 1 , supply openings (not shown) of supply chamber 20 are provided. Belt 1 and rotatable part of first guiding wheel 2 are adapted and guided such that supply openings in supply chamber 20 coincide and move together with the orifices 10 in conveyor belt 1 . During this parallel guiding of supply opening and orifice, the orifice is filled with particulate material from supply chamber 20.

Gas supply openings 201 in supply chamber 20 may also be used for introducing for example ionized air for keeping the particulate material in the supply chamber agitated and preventing or limiting an electrostatic charging of the particulate material.

In the embodiment of Fig.2, supply chamber 20 in first guiding wheel 2 does not extend all the way to transfer location 100, especially a supply opening in supply chamber 20 for the transfer of particulate material from supply chamber 20 into orifice 10, is located upstream of transfer location 100 (with respect of a clockwise rotational direction). Thus, an amount of particulate material is filled into orifice 10 before orifice 10 reaches transfer location 100. Said amount of particulate material is filled into cavity 51 at transfer location 100 and while orifice 10 and cavity 51 are guided along straight belt portion 12. Cavity 51 is thus filled with an amount of particulate material which amount is metered and defined by the volume of orifice 10.

If a stream of rod-shaped elements shall be designed differently or if a cavity 51 shall be filled with a different amount of particulate material, this may be done by replacing a conveyor belt by another conveyor belt including orifice sizes or orifice-to-orifice distances according to the different stream of rod-shaped elements, especially to differently sized cavities. An amount of particulate material may also be defined by the time an orifice and a cavity coincide while orifice 10 is still receiving particulate material from supply chamber 20. In such an embodiment a supply opening in supply chamber 20 is arranged up to the transfer location 100 or a transfer location is arranged in a more upward direction, respectively.

Fig. 3 shows a detail of the apparatus according to the invention at transfer location 100 in a cross sectional view as seen in a transportation direction of conveyor belt 1 and of stream of rod-shaped elements 5. Orifice 10 in conveyor belt 1 is arranged at transfer location 100. Cavity 51 is arranged below orifice 10. A rod-shaped element 50 is arranged in front of cavity 51 . The stream or rod- shaped elements is kept and guided in a stream support 54. A wrapping material 53, such as a paper sheet or a plastic foil, is arranged and guided in stream support 54 thereby holding rod-shaped elements 50 and cavities 51 in place in the stream of rod-shaped elements, while the cavities 51 are being filled. Stream support 54 mainly has a rod-shaped circularly formed groove 541 therein. The diameter of groove 541 may vary along the transportation path of the stream of rod-shaped elements and may be adapted when perfoming the different steps of the method according to the invention. Wrapping material 53 basically forms an inner lining of groove 541 . Additionally, a groove 542 is provided for a belt that transports the web of sheetlike material that is used to wrap the stream of rod- shape articles. Wrapping material 53 extends to and around both edges of the open ends of groove 541 . These extending portions 530 of wrapping material 53 are used after filling of cavities 51 for closing the stream of rod-shaped elements. Thus a continuous rod-shaped article is formed for being cut into individual elements, such as filter elements, for example comprising a filter plug 50 and a filled cavity 51 .

Orifice 10 is formed in conveyor belt 1 in the shape of a funnel. Orifice 10 comprises an outlet opening 102, a conical section 103 directing particulate material into the direction of the outlet opening and an insert 104 being larger than the outlet opening 102. Insert 104 may for example be a ring-shaped metal insert such as stainless steel. Insert 4 stabilizes orifice 10 when being filled, emptied or cleaned. A metal insert may also reduce electrostatic charging of particulate material and thus support the reliable filling of cavities.

In Fig. 4 pusher wheel 4 with a pin-shaped cam 40 inserted into orifice 10 is shown. Pusher wheel 4 is arranged above conveyor belt 1 and after transfer location 100. Circumferentially running teeth 41 on pusher wheel 4 interact with teeth 1 1 of conveyor belt 1 . By this, pusher wheel 4 is made to rotate and by this movement cam 40 penetrates and retracts from orifice 10. Particulate material not yet transferred to cavity 51 arranged below orifice 10 and between two rod-shaped elements 50 (only one is seen) is pushed by cam 40 out of orifice 10. Remaining particulate material in orifice 10 that has not yet been transferred to cavity 51 by gravitational force and through general apparatus vibrations while orifice 10 and cavity 51 have been moving together along straight belt portion 12 (see Fig. 1 ), is pushed by cam 40 into the direction of cavity 51 .

Preferably, pusher wheel 4 and conveyor belt 1 are distanced such that cam 40 does not touch any surface of the orifice 10 or belt 1 , respectively, while cam 54 is being inserted and retracted from orifice 10. A minimal distance 42 between cam and orifice is preferably chosen to be larger than a diameter or an average extension of the particles of the particulate material such that no particulate material gets squeezed or ruptured by cam 40 and orifice 10.

Preferably, at least one cam is arranged on pusher wheel 4. The distance of cams 40 following each other is equal to a distance between orifices 10 following each other in conveyor belt 1 .

In Figs. 5 to 8 the process of rod cleaning by rod-cleaning unit 61 is shown.

A cleaning wheel 610 comprises a plurality of recesses 6100 regularly arranged around the circumference of cleaning wheel 610 giving cleaning wheel 610 the shape of a lobed wheel. Cleaning wheel 610 further comprises a plurality of regularly arranged through-holes 6101 arranged in the lobes of cleaning wheel 610. Thus, through-holes 6101 are arranged in between recesses 6100 and provide closed passages from a front side of cleaning wheel 610 to a back side of cleaning wheel 610. Rod-cleaning unit 61 further comprises a cleaning interface 612 arranged above and parallel to the stream of rod-shaped elements 5. Cleaning interface 612 comprises a gas flow passage. This gas flow passage allows a gas stream from a gas inlet 61 1 to enter cleaning interface 612, to be directed to a rod-shaped element 50 (indicated in Fig. 6 and 8) arranged below cleaning interface 612, to be directed back from the rod-shaped element into cleaning interface 612 and to the rear side of cleaning wheel 61 and further via a gas outlet 613 to second cleaning unit 62 (not shown) for cleaning second guiding wheel 3 and conveyor belt 1 (see Fig. 1 ). Preferably, the second cleaning unit 62 is provided with a separate cleaning channel (not shown). Cleaning wheel 61 is also arranged above the stream of rod-shaped elements 5 and perpendicular a transportation direction of the stream of rod- shaped elements. Cleaning wheel 610 is further arranged in cleaning interface 612 such to enable the gas stream to pass from a front side of cleaning wheel 610 to a rear side of cleaning wheel 610, either through the through-holes 6101 of cleaning wheel 610 or through that part of the gas flow passage in cleaning interface 612 directing towards and away from rod-shaped element 50.

Fig. 5 and 6 show rod-cleaning unit 61 in an open position, Fig. 7 and 8 show rod-cleaning unit 61 in a closed position. In the open position, cleaning wheel 610 is arranged such that a recess 6100 comes to lie above rod-shaped element 50 of the stream of rod-shaped elements. Thus the gas stream enters interface 612, is directed to and away again from rod-shaped element 50 and into rod-cleaning unit 61 again. By this, stray particulate material is blown or sucked away from rod-shaped element 50 by the gas stream or through suction. In the closed position, cleaning wheel 610 is arranged such that a through-hole 6101 is arranged in the gas flow passage of cleaning interface 612, closing off the part of the gas flow passage leading to and from the rod-shaped element 50. Cleaning wheel 610 is positioned in the closed position when a cavity 51 passes rod- cleaning unit 61 such as to not inadvertently remove particulate material from cavity 51 . Closed and open positions of cleaning unit 61 are achieved by rotation of cleaning wheel 610. Accordingly, a rotational speed of cleaning wheel 61 1 is adapted to the arrangement of cavities and rod-shaped elements in the stream of rod-shaped elements and a transportation speed of the stream of rod-shaped elements. For example, by way of adapting a (length) size of recess 6100 (with respect to the width of cleaning wheel 610), a cleaning action of rod-shaped element 50 may be defined and especially limited to the length or part of the length of rod-shaped element 50. A gas stream or suction may be applied very locally not putting particulate material to the risk of inadvertently being sucked out of a cavity.

Rod-cleaning unit 61 may also be adapted to be used for supporting a filling of a cavity. For example, if the wrapping material 53 of a stream of rod-shaped elements 5 is made of a material with low gas permeability, no suction may be applied through the wrapping material, for example from below a cavity, for supporting the filling of cavity 51 . However, if rod-shaped elements are made of gas-permeable material or a portion of the rod-shaped element 50 arranged next to a cavity 51 is made of a gas-permeable material suction may be applied to rod- shaped element 50 or to the part of the rod-shaped element made of gas- permeable material. If suction is applied in a strong enough intensity, this suction acts through the gas-permeable material of rod-shaped element 50 in a longitudinal direction of the rod-shaped element and onto the cavity 51 . This suction may support a filling of cavity 51 and may keep particulate material in the cavity 51 . For example, a gas stream is applied to the stream of rod-shaped elements for cleaning. Such a filling support unit may also be arranged at a more upstream position, closer to transfer location 100.

A gas stream may for example be provided by a gas source providing a gas flow or by a vacuum source providing suction applied to cleaning wheel 610. For a cleaning action of a rod-shaped element, or a cleaning action in general, a gas stream or suction of moderate strength may be applied. For supporting a filling of a cavity suction of intense strength may be required. In order not to inadvertently remove particulate material from a cavity, a localization of the suction action to the gas-permeable material of the rod-shaped element may be recommendable, for example by the provision of recesses and through-holes in a cleaning wheel as described with regard to Figs.5 to 8. A gas stream for cleaning may for example also be an ionized gas stream for electrostatically decharging of particulate material, of the stream of rod-shaped elements or of parts of the filling machinery. An electrostatic decharging may also be applied before a cleaning step is provided.

Claims

1 . Apparatus for filling cavities with particulate material, the apparatus comprising:

- a conveyor belt comprising an orifice, wherein the orifice is adapted for accommodating particulate material and for dispensing the particulate material through the orifice;

- a first guiding wheel and a second guiding wheel for transporting and guiding the conveyor belt, the first guiding wheel and the second guiding wheel being arranged at a distance to each other and such that the conveyor belt comprises a straight belt portion arranged between the first guiding wheel and the second guiding wheel;

- a retention element arranged adjacent the lower side of the conveyor belt for keeping the orifice closed before the orifice reaches a transfer location at the first guiding element, the retention element and the straight belt portion further being arranged to allow particulate material in the orifice to be dispensed through the open orifice at the transfer location,

wherein the particulate material is transferred to the conveyor belt through the first guiding wheel.

2. Apparatus according to any one of the preceding claims, further comprising a pusher element arranged next to an upper side of the straight belt portion, the pusher element comprising a cam for being inserted into the orifice of the conveyor belt for pushing particulate material out of the orifice.

3. Apparatus according to any one of the preceding claims, the first guiding wheel comprising a supply chamber for holding an amount of particulate material, the supply chamber being arranged inside the first guiding wheel, wherein the supply chamber is provided with a supply opening in a supply periphery of the supply chamber, which supply periphery corresponds to a peripheral portion of the first guiding wheel, and wherein the supply opening is provided for supplying particulate material from the supply chamber through the supply opening to the orifice in the conveyor belt, when the orifice is arranged at the peripheral portion of the first guiding wheel.

4. Apparatus according to claim 3, wherein the supply chamber comprises circulation means for affecting a circulation of the particulate material with the supply chamber.

5. Apparatus according to any one of the preceding claims, further comprising an apparatus cleaning unit for removing particulate material from the first guiding wheel, from the second guiding wheel or from both the first guiding wheel and the second guiding wheel.

6. Apparatus according to any one of the preceding claims, further comprising a rod cleaning unit arranged downstream of the second guiding wheel, wherein the rod cleaning unit is adapted for removing stray particulate material from an area next to a cavity provided in a stream of rod-shaped elements, and is arranged next to a longitudinal end of a rod- shaped element of the stream of rod-shaped elements.

7. Apparatus according to any one of the preceding claims, wherein the first guiding wheel and the second guiding wheel is a first toothed wheel and a second toothed wheel and wherein the conveyor belt is a toothed belt arranged along a circumference of the first and of the second toothed wheel.

8. Apparatus according to any one of the preceding claims, further comprising an ionization unit for electrostatically discharging particulate material.

9. Method for filling cavities with particulate material, the method comprising the steps of: - providing a conveyor belt comprising an orifice,

- transporting and guiding the conveyor belt by a first guiding wheel and a second guiding wheel, thereby arranging the first guiding wheel and the second guiding wheel at a distance to each other such that the conveyor belt forms a straight belt portion between the first guiding wheel and the second guiding wheel;

- filling the orifice with particulate material through the first guiding wheel while keeping the orifice closed; and

- arranging a cavity in a stream of rod-shaped elements adjacent to the orifice at a transfer location; then

- dispensing the particulate material through the open orifice into the cavity arranged adjacent to the orifice, while guiding in parallel the orifice in the conveyor belt and the cavity in the stream of rod-shaped elements along the straight belt portion.

10. Method according to claim 9, further comprising the step of inserting a cam into the orifice, thereby pushing particulate material out of the orifice.

1 1 . Method according to claim 9 or 10, further comprising the steps of

- providing particulate material in a supply chamber arranged in the first guiding wheel;

- guiding the orifice along the first guiding wheel such as to pass a supply opening in the supply chamber; and

- supplying particulate material from the supply chamber through the supply opening to the orifice in the conveyor belt.

12. Method according to claim 1 1 , further comprising the step of affecting a circulation of the particulate material in the supply chamber.

13. Method according to any one of claims 9 to 12, further comprising the step of removing stray particulate material from the stream of rod-shaped elements by applying suction or by directing a gas stream to a rod-shaped element of the stream of rod-shaped elements.

14. Method according to claim 13, providing rod-shaped elements comprising gas-permeable material and applying suction to the rod-shaped element comprising gas-permeable material such that suction acts through the gas- permeable material and on the cavity arranged next to the rod-shaped element comprising gas-permeable material thereby supporting a filling of the cavity with particulate material.

15. Use of the apparatus according to any one of claims 1 to 8 or of the method according to any one of claims 9 to 14 in the manufacture of filter elements for smoking articles.