DEVICE AND METHOD FOR DISCHARGING MATERIAL ON A MOVING SUBSTRATE

Abstract

 A device and a method for discharging particle material, such as powder material, granules or capsules, or generally a free-flowing material, such as, for example, adhesive material, onto a substrate (S) moving in a conveying direction (A). A drum rotor (R), having a plurality of cavities (E1, E2, ...) suitable to carry the material to be deposited, is arranged adjacent to the moving substrate (S), with the axis (X) of the drum rotor (R) substantially parallel to the conveying direction (A). The cavities are arranged on the drum rotor (R) whereby the rotary motion of the drum rotor (R) in combination with the movement of the substrate (S) in the conveying direction (A) causes each cavity, when it is closest to the substrate, to follow a helical path relative to the substrate.

Description

Field of the invention

[0001] The present invention concerns a device and a method for discharging particulate material, such as powder material, granules or capsules, or in general free-flowing material, such as adhesive material, on a substrate moving along a conveying direction.

[0002] The present invention may be used in various fields and is not intended to be limited to a specific field of application. However, the invention has been found to be particularly useful in the field of machines for the production of smoking articles, for example, for the production of filters.

Prior art

[0003] Figure 1 of the accompanying drawings shows an example of a device known from document US-A-3 550 508 for the production of filters for cigarettes or other smoking articles. This known device is used for feeding capsules 1 and granules 9 into gaps defined between filter segments 2 which are made to advance along with a web 3 of wrapping material on which the segments are deposited. The web 3 is made to advance by a conveyor belt which is not shown in the figure. The capsules 1 and granules 9 are discharged into the gaps between filter segments 2 before the web 3 is wrapped around the segments 2, in an area downstream of the position illustrated in figure 1. In this known solution, the capsules 1 and granules 9 are fed by gravity from hoppers 7,8 into peripheral pockets 5 of a rotor 4 arranged above the line for conveying the filter segments 2 and having its axis directed orthogonally to the conveying direction of filter segments 2. The portion of the outer surface of the rotor 4, which is located downstream of the hoppers 7,8 (with reference to the rotation direction of the rotor 4, which is clockwise in the figure), cooperates with an outer cover extending between the hopper 8 and the area for discharging the material, whereby the capsules and the granules received within the pockets 5 are held within such pockets until each pocket reaches the lowermost position during the rotation, where capsules and granules contained within the pocket are free to fall into the gap between two subsequent filter segments 2.

[0004] Figure 2 shows another known solution, which is described in US-A-3,312,151. In such solution, similarly to the solution of figure 1, there is provided a rotor 23 having pockets 24 for receiving powder material from a hopper 25. The rotor 23 has a tubular wall within which a stator 27 is arranged to which is associated a suction chamber 28, which communicates with a vacuum source and faces the inner surface of the tubular wall of the rotor. Each pocket 24 has drillings 27 at its base which lead to the inner surface of the tubular wall of the rotor, whereby the suction chamber 28 is able to retain by suction the powdered material received within the pockets 24, while these pockets move from the hopper 25 in the direction of the discharge position, where the material falls into the gap between two successive filter segments P which advance along a conveying direction. Figure 2 shows the filter segments P resting on a wrapping web 14 which is in turn resting on a conveyor belt 15. In the case of the known solution of figure 2, the step of discharging the material is facilitated and accelerated by a suction chamber 30 placed underneath the belts 14,15, which are perforated.

[0005] Other known solutions of the type described above are, for example, illustrated in documents US 7,849,889 B2, US-A-5,875,824, US-A-4,425,107.

[0006] The main drawback of such known solutions is that the step of discharging the material contained in each pocket of the rotor must be carried out in the time interval wherein the pocket is around the lowermost position, proximal to the conveying line of the filter segments. This obviously poses a limit to the conveying speed of the filter segments and consequently to the productivity of the machine.

[0007] The aforesaid problem is, however, common to any other application where a device of the type indicated above is intended to discharge particulate matter, or in general free-flowing material, onto a moving substrate. For example, a similar problem is found also in devices of the type illustrated in US 8,590,582 B2, which relates to the field of machines for the production of absorbent sanitary articles.

[0008] An effective solution to the aforementioned problems is represented by the device and the method forming the subject of document WO 2016/088039 A1, by the same Applicant. In such known solution, at least one drum rotor is arranged adjacent to the moving substrate, with the drum rotor axis substantially parallel to the conveying direction of the substrate. In a first embodiment, the rotor has one or more continuous helical paths carrying the material to be deposited. In a second solution, suitable for the deposit of material in the form of granules, capsules or the like, the rotor carries a plurality of cavities carrying said material, arranged on the drum according to one or more helical paths (or "tracks").

[0009] The preambles to the accompanying independent claims 1 and 10 are based on the aforementioned document WO 2016/088039 A1.

Object of the invention

[0010] The purpose of the present invention is to create a device and a method for discharging particle material, such as powder material, granules or capsules, or in general free-flowing material, such as also adhesive material, on a substrate moving along a conveying direction, ensuring under any operative condition that the discharging operation is carried out efficiently and reliably, without posing any strict limits to the conveying speed of the substrate.

Summary of the invention

[0011] In view of achieving such object, the invention has as its object a machine comprising:

• conveying means, to convey a substrate in a conveying direction,
• a device for discharging particle material, such as, for example, powder material, granules or capsules, or in general free-flowing material, such as, for example, adhesive material, onto said substrate moving along said conveying direction,
• said device comprising at least one drum rotor having a plurality of cavities suitable for carrying the material to be deposited, said drum rotor being arranged adjacent to the substrate, with the axis of the drum rotor substantially parallel to said conveying direction,
• means for controlling the rotation of said drum rotor,

said machine being characterized in that the aforesaid cavities are arranged in such a way, whereby, in operation, the rotary motion of said drum rotor, in combination with the movement of the substrate in said conveying direction causes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

[0012] The present invention is based on the recognition of the fact that, in order to achieve the indicated objects, the drum rotor may be equipped with cavities that do not define one or more helical tracks on the rotor itself, as in the case of the solution known from WO 2016/088039 A1, but are still arranged in such a way that the rotary motion of the drum rotor, in combination with the movement of the substrate in the conveying direction, causes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

[0013] For example, in a first embodiment, the drum comprises at least one circumferential series of cavities arranged on the drum substantially in the same plane orthogonal to the axis of the drum.

[0014] In a second embodiment, the drum comprises at least one series of cavities aligned in a direction parallel to the drum axis.

[0015] Variants are possible corresponding to combinations of the aforesaid solutions. For example, the drum rotor may have two or more circumferential series of cavities, axially spaced from each other, and for example two or more series of cavities aligned in axial directions and equally spaced angularly on the drum rotor.

[0016] In all of the aforesaid solutions, each cavity, when moving near the substrate as a result of the rotation of the drum, travels a helical path relative to a theoretical reference point moving with the substrate.

[0017] Due to the aforesaid feature, the method according to the invention guarantees the material discharging operation is carried out efficiently and reliably, even when the substrate is conveyed at high speed.

[0018] The invention also has as its object a method for discharging particle material, for example, powdered material, granules or capsules, or in general free-flowing material, such as, for example, adhesive material, onto a substrate moving in a conveying direction, wherein is provided at least one drum rotor with a plurality of cavities suitable to carry the material to be deposited, said drum rotor being positioned adjacent to the moving substrate, with the axis of the drum rotor substantially parallel to said conveying direction and wherein said drum rotor is rotated around its axis, the method being characterized in that the aforesaid cavities are arranged on the drum rotor in such a way that the rotary motion of the drum rotor, in combination with the movement of the substrate in said conveying direction, makes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

Description of some embodiments

[0019] Further features and advantages of the invention will become apparent from the detailed description that follows, made with reference to the accompanying drawings, provided by way of non-limiting example, wherein:

• figures 1, 2, already described in the foregoing, show two devices of the prior art,
• figure 3 is a schematic perspective view showing a drum rotor as part of a device known from document WO 2016/088039 A1,
• figure 4 is a schematic view in cross-section of the aforesaid known device,
• figure 5 is a perspective view partially in cross-section of the drum rotor according to a variant also known from WO 2016/088039 A1,
• figure 6 is a variant of figure 3, also known from WO 2016/088039 A1, wherein the drum rotor has a plurality of discontinuous helical tracks, each defined by a plurality of cavities distributed along a respective helical path,
• figure 7 shows a detail in cross-section of the solution in figure 6, in a plane orthogonal to the axis of the drum rotor, and
• figure 8 shows a cross-section along the line VIII-VIII of figure 7;
• figures 9, 10 show two embodiments of the drum rotor, used in the machine and in the method according to the present invention.

[0020] Figures 1, 2 have already been described above.

[0021] Figure 3 shows a solution known from WO 2016/088039 A1. In such figure the reference R generally designates a drum rotor which is arranged adjacent to a substrate S moving along a direction A. The example shown relates to the application to a machine for production of filters for cigarettes or smoking articles, wherein the substrate is constituted by an aligned series of filter segments F1, F2 which are supported on a wrapping web W moving in direction A. The means for conveying the wrapping web W may be constituted by a conveyor belt, similarly to what has been described with reference to the known solutions of figures 1, 2.

[0022] In the specific example shown, the filter segments F1, F2 that are arranged on the web W have different lengths. Each filter segment is spaced from the adjacent filter segment so as to define a gap G to be filled with particle material, e.g. powdered, granular or capsule material.

[0023] As shown in figure 3, the drum rotor R is arranged adjacent to the web W with its axis X parallel to the conveying direction A of the web. The drum rotor R has at least one helical track carrying the material to be discharged. Preferably, there are provided many helical tracks which are axially spaced from each other. In figure 3, two helical tracks E1, E2 are shown, each having subsequent turns e11, e12, ...; e21, e22, ..., which extend throughout the entire axial dimension of rotor R. In an actual exemplary embodiment four helical tracks are provided, constituted by four helical channels formed in the outer surface of rotor R.

[0024] During rotation of rotor R, the particulate material contained within the helical channels E1, E2 is held within these channels, in a way which will became apparent in the following, until the material comes to be at the lower area of the rotor R adjacent to web W, where the material is discharged on the web.

[0025] The arrangement of channels E1, E2 on the rotor R and the position of these channels with respect to the sequence of filter segments F1, F2 is selected in such a way that the portion of each channel which is adjacent to the web W comes to be at a gap G between two adjacent filter segments. The speed of rotation of the drum rotor R is synchronized with the speed of advance of web W along direction A, so that the portion of each helical channel E1, E2 adjacent to the web tracks the respective gap G by moving at its same speed. Therefore, the operation for discharging the material into each gap G may be completed within the entire time interval taken by each gap G to move from one end of the drum rotor R to the other. Clearly, this ensures the possibility of carrying out the operation for discharging the material in an efficient and reliable way, without posing any strict limits to the maximum speed of movement of the web W, thereby providing a high productivity of the machine.

[0026] Figure 4 shows an embodiment wherein the tubular cylindrical wall of the drum rotor R is rotatably supported by an inner stator Si and an outer stator Se which defines a feeding inlet B. The feeding inlet B is located at the lower end of a feeding hopper T which is intended to receive the particulate material to be fed on the web W.

[0027] A suction chamber CA is associated with the inner stator Si, which communicates with a vacuum source (not shown) and further communicates with a chamber defined between the outer surface of the inner stator Si and the inner surface of the drum rotor R.

[0028] As already indicated in the foregoing, the outer surface of the drum rotor R is formed with the aforesaid plurality of helical channels E1, E2. The bottom wall of each channel is perforated, to enable the passage of air towards the suction chamber CA. The suction effect facilitates and accelerates the step of loading the particulate material into the channels E1, E2, as such channels arrive with their empty portions below the hopper T.

[0029] Naturally, the provision of a suction system to accelerate the material loading step is preferred but is not essential. This measure has the advantage of enabling the feeding inlet B to be provided not necessarily above rotor R, but alternatively on one side thereof, if this should be necessary.

[0030] In figure 4, as also in figure 3, the direction of rotation of the drum rotor R is indicated by arrow ω. The rotor is driven in rotation by an electric motor (not shown) by any kind mechanical transmission (not not shown).

[0031] In the specific example shown in figure 4, at the inlet B there is provided a rotating roller Z for facilitating a proper feeding of the material into the channels E1, E2. Furthermore, at an area downstream of the feeding inlet B, with reference to the direction of rotation of rotor R, a rotating brush BR is provided, which is adapted to dose the material on the helical channels E1, E2 of the drum rotor R.

[0032] Again in the case of the preferred embodiment shown herein, a blowing chamber CS is associated with the inner stator Si which communicates with a source of pressure and has a communication channel 100 opening in front of the inner surface of the drum rotor R at the lower position of the roller, adjacent to web W. During operation, air blown from chamber CS flows through holes provided on the bottom wall of the helical channels E1, E2 thereby accelerating the discharging step of the material on the web W.

[0033] Again with reference to figure 4, the outer stator Se has a lower wall 101 which separates the drum rotor R from the substrate S and has a slot 102 extending in the longitudinal conveying direction A (figure 3) for the passage of the discharged material.

[0034] The accompanying drawings do not show the details of construction relating to the motors for actuating rotation of the drum rotor R and the brush BR, which may be of any known type.

[0035] The operation of the above described device is as follows.

[0036] The wrapping web W carrying the aligned sequence of filter segments F1, F2, (figure 3) is moved in the conveying direction A, at a predetermined conveying speed. The drum rotor R provided adjacent to web W is rotated in the direction ω at a speed synchronized with the conveying speed of the wrapping web, so that the portion of each helical channel E1, E2, etc. adjacent to the wrapping web W moves axially at a speed substantially corresponding to the conveying speed of web W.

[0037] Each helical channel E1, E2 receives particulate material from the hopper T in the stage wherein a portion thereof comes to be facing such hopper. The loading of the material into each channel is preferably facilitated by the suction effect due to the suction chamber CA. The portions of the helical channels filled with particulate material coming from the hopper T, with the continuing rotation around the axis X, come to be at the roller brush Z, which removes excess material from the outer surface of the drum rotor R. As a result of the continued rotation around the axis X, the brush BR doses the material in the channels E1, E2. At the area between the brush BR and the material discharging position, the material is held within channels E1, E2 by a wall of the outer stator Se which surrounds the rotor R and/or due to the suction effect of the suction chamber CA (in this case communication channels are provided also in this area of the inner stator Si).

[0038] As the material contained in each of the helical channels E1, E2 reaches the discharge position, it is discharged onto the moving web W, flowing through the longitudinal slot 102 of wall 101. Such discharging action is preferably facilitated by the blowing action due to the blowing chamber CS, even if such measure is not absolutely essential (as the provision of the suction chamber CA).

[0039] As already indicated in the foregoing, the configuration of the drum rotor R and in particular the configuration and the arrangement of the helical channels, E1, E2, etc. and the speed of rotation of the rotor R are such that the portion of each channel which is adjacent to the web W moves progressively in the conveying direction A of the web W at the same speed as the web, thus always facing a respective gap G between two adjacent filter segments. In other words, the portion of the helical channel which discharges the material onto the web W tracks a respective gap G in its movement along the direction A. Therefore, the filling of each gap G may be performed during the time necessary for said gap to move in the direction A from one end to the other of the drum rotor R. This represents the main advantage of the present invention, from which is derived the possibility of insuring a complete and reliable discharge of the material with no need of posing limits to the maximum conveying speed of the web W.

[0040] In an alternative embodiment, in order to facilitate the material discharging step, one or more helical channels are provided, each having a movable or deformable wall. In this case, the inner stator is provided on one side adjacent to the discharging area of the material with a device for pushing said movable or deformable wall radially outward, in order to push the material contained within the helical channel out of the channel and over the substrate. In an actual embodiment of such solution, which is schematically shown in figure 5, the helical channels E1, E2 are defined by helical slots formed through the tubular wall of the drum rotor R. The bottom wall of the channels is defined by an inner lining tube V forming part of the drum rotor R, constituted of an elastically deformable material (such as rubber). As shown in figure 5, the inner stator of the drum rotor R comprises a series of guiding rollers 103, freely rotatable around their respective axes, for guiding and supporting the inner surface of the rubber tube V during rotation of rotor R. The inner stator further carries a main roller 104 the axis 104a and the diameter of which are determined in such a way that such roller 104 applies an outward radial thrust on the portion of the wall of the rubber tube V which comes to be interposed between roller 104 and the inner surface of the rotor. Therefore, at the discharging area, the bottom of each helical channel is moved radially outward so as to push the material contained within the channel out of the channel and on the web W which passes below the rotor R. In the specific example shown in figure 5, the rubber tube V has a helical rib at each helical channel of the rotor R. Such rib occupies the respective channel only for a portion of the thickness of the channel, so as to define the bottom wall of the channel.

[0041] In a further alternative embodiment, the helical path provided on the drum rotor is constituted by a helical rib carrying adhesive material to be applied on a substrate. In such solution, the device according to the invention is used for depositing the adhesive material on the moving substrate.

[0042] Figure 6 schematically shows a variant of figure 3, which is also known from document WO 2016/088039 A1, wherein the drum rotor R has a plurality of discontinuous helical tracks E1, E2, etc..., each defined by a plurality of cavities E11, E12, E13, etc..., E21, E22, E23, etc... distributed along a respective helical path.

[0043] Figures 7,8 show an embodiment of the solution of figure 6, wherein within each cavity Exy there is slidably mounted a piston 20 movable between a retracted position, for receiving particulate material within the cavity and an advanced position, for discharging the particulate material out of the cavity.

[0044] In the illustrated example, each piston 20 is biased by a spring 21 (figure 8) towards its retracted position, against a stop member 22 carried by the structure of the drum rotor R. The fixed structure within which the shaft 23 of rotor R is rotatably mounted carries fixed cams 24 which cause the movement of each piston 20 to its advanced position when the cavity wherein the piston is mounted comes to be at the lower part of the rotor, in the material discharging area. As an alternative to the use of mechanical means for actuating the movement of pistons 20 within the respective cavities, it is possible to make use of magnetic or electromagnetic means. Figure 7 shows the different positions taken by a same piston 20 immediately before, during and immediately after discharging the material contained in a respective cavity.

[0045] In the case of application to a machine for production of filters for cigarettes or smoking articles, in all the embodiments of the invention it may be provided that the substrate on which the material is discharged is not constituted by an aligned series of filter segments supported on a moving web, as described with reference to figure 3, but rather is constituted by an aligned series of receptacles moving along the aforesaid conveying direction A, which receive the material from the drum rotor R and discharge the material, at a position located further ahead, on an aligned series of filter segments which are supported on a moving wrapping web.

[0046] Figure 9 shows a schematic perspective view of a drum rotor according to an embodiment that is used in the machine and in the method according to the invention. The machine according to the invention may be actuated in the way already described with reference to figures 3-8, barring the different shape of the drum rotor R.

[0047] As already indicated above, the present invention is based on the observation that, in order to achieve the indicated objects, the drum rotor may be equipped with cavities that do not define one or more helical paths on the same rotor, as in the case of the solution known from WO 2016/088039 A1, but are still arranged in such a way that the rotary motion of the drum rotor, in combination with the movement of the substrate in the conveying direction, causes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

[0048] In the case of the solution in figure 9, the drum rotor R has a single circumferential series of cavities E1, E2, E3, etc. arranged thereon, substantially in a same plane orthogonal to the axis X of the rotor.

[0049] During operation, the rotor is driven in rotation (by an electric motor and a mechanical transmission of any known type, not shown here) at a rate synchronized with the speed of advance of the substrate, whereby, during each turn of the rotor R, the cavities E1, E2, E3, etc. are located in sequence near as many areas of the substrate ready to receive the material. Whenever a cavity is in proximity of the substrate, it completes, from a fixed reference point to the substrate, a helical path. A small portion of such helical path is used to carry out the discharge operation of the contents of each individual cavity into the corresponding receiving area on the substrate.

[0050] Figure 10 shows a different embodiment, wherein the drum rotor R comprises a single series of cavities E1, E2, E3, etc. arranged thereon, aligned in a direction parallel to the axis of the drum rotor R. In operation, at each turn of the rotor R, the series of cavities E1, E2, E3, etc. is located near as many areas of the substrate ready to receive the material. Whenever a cavity is in the proximity of the substrate, it completes, from a fixed reference point to the substrate, a helical path. A small portion of this helical path is used to carry out the discharge operation of the contents of each individual cavity into the corresponding receiving area on the substrate.

[0051] Variants are possible corresponding to combinations of the aforesaid solutions. For example, the drum rotor may have two or more circumferential series of cavities, axially spaced from each other, and, for example, two or more series of cavities aligned in axial directions and equally spaced angularly on the drum rotor.

[0052] All the details of implementation that have been illustrated with reference to the solution known from document WO 2016/088039 A1 are also implementable in the case of the present invention. In particular, also in the case of the present invention, it may be provided that said cavities on the drum rotor R are associated with suction means to facilitate the loading of material into said cavities and/or blowing means or piston means to facilitate the discharge of material from said cavities over the substrate S.

[0053] Naturally, while the principle of the invention remains the same, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated purely by way of example, without departing from the scope of the present invention.

Claims

1. Machine comprising:

- conveying means (15), to convey a substrate (S) along a conveying direction (A),

- a device for discharging particle material, such as powder material, granules or capsules, or in general a free-flowing material, such as, for example, adhesive material, onto said substrate (S) moving along said conveying direction (A),

- said device comprising at least one drum rotor (R) having a plurality of cavities (E1, E2, ...) suitable for carrying the material to be deposited, said drum rotor (R) being placed adjacent to the substrate (S), with the axis (X) of the drum rotor (R) substantially parallel to said conveying direction (A),

- means of controlling a rotation of the drum rotor (R) around the axis thereof,

said machine being characterized in that the aforesaid cavities are arranged on the drum rotor (R), whereby, in operation, the rotary motion of the drum rotor (R), in combination with the motion of the substrate (S) along said conveying direction (A), causes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

2. Machine according to claim 1, characterized in that said drum rotor (R) comprises at least a circumferential series of cavities arranged thereon, substantially in the same plane orthogonal to the axis of the drum rotor (R).

3. Machine according to claim 1, characterized in that said drum rotor (R) comprises at least a one series of cavities arranged thereon, aligned in a direction parallel to the axis of the drum rotor (R).

4. Machine according to claim 1, characterized in that said cavities are associated with suction means to facilitate the loading of material into said cavities.

5. Machine according to claim 1, characterized in that said cavities are associated with blowing means or piston means to facilitate the discharge of material from said cavities over the substrate (S).

6. Method for discharging particle material, such as powdered material, granules or capsules, or in general free-flowing material, such as, for example, adhesive material, onto a substrate (S) moving in a conveying direction (A), wherein is provided at least one drum rotor (R) with a plurality of cavities (E1, E2,...) suitable to carry the material to be deposited, said drum rotor (R) being positioned adjacent to the moving substrate (S), with the axis (X) of the drum rotor (R) substantially parallel to said conveying direction (A) and wherein said drum rotor (R) is rotated around its axis, the method being characterized in that the aforesaid cavities are arranged on the drum rotor (R) in such a way that the rotary motion of the drum rotor (R), in combination with the movement of the substrate (S) along said conveying direction (A), causes each cavity, when it is closest to the substrate, to follow a helical path relative to a reference point that moves with the substrate.

Drawing