Roller dispenser

Abstract

The invention relates to a drum dispenser (3) for producing individual dispensed quantities (2) of a powdered product (1). The drum dispenser (3) comprises a product reservoir (4) arranged in a filling position (I), a dispensing drum (5) and a rotary drive (M) for the dispensing drum (5). The dispensing drum (5) has dispensing openings (7, 7) distributed on the circumferential side. At least two dispensing openings (7, 7), which are spaced apart from each other in the circumferential direction (U) of the dispensing drum (5), are joined to form a common dispensing section (12). The rotary drive (M) is designed for a clocked rotation of the dispensing drum (5) about the axis of rotation (19) in such a way that the individual dispensing sections (12) and the associated dispensing openings (7, 7) are periodically at least in the filling position (I) and in the discharge position (III).

Description

TECHNICAL FIELD

[0001] The invention relates to a drum doser for producing individual dosing quantities of a powdery product, comprising a product reservoir arranged in a filling position, a dosing drum and a rotational drive for the dosing drum, wherein the dosing drum has dosing openings distributed in a circumferential side. BACKGROUND

[0002] Powders are processed, for example in the pharmaceutical sector, but also in the sector of nutritional supplements and the like, which must be provided in precisely measured partial quantities or dosing quantities for a defined administration form. Such measured dosing quantities of a powdery product are used to fill target containers in the form of, for example, transparent plastic covers, plug-in capsules and the like, so that the consumer can obtain corresponding unit doses and take them.

[0003] Such powdery products are converted into individual measured dosing quantities, in particular on so-called drum dosers, and the dosing quantities are then filled into the corresponding associated target containers. Such drum dosers comprise a product reservoir, a dosing drum and a rotational drive for the dosing drum.

[0004] The dosing drum has a plurality of dosing openings distributed in a circumferential side. The dosing drum is rotated clock-controlled about a rotational axis, so that individual dosing openings or axially parallel rows thereof are in different positions. In a first position of the dosing openings, the filling position, there is the product reservoir. In the filling position, the powdery product is sucked from the product reservoir into the rows of dosing openings, for example under the action of a negative pressure. There, the dosing quantity of powder is formed, the volume of which corresponds to the volume of the respective dosing opening. After the filling process, the dosing drum is rotated clock-controlled further, so that the row of dosing openings previously filled is now in the region of the discharge position. There, the previously formed dosing quantity is then discharged from the dosing openings and transferred to the target container, for example by means of an overpressure.

[0005] Generally, such a dosing drum is provided with a plurality of rows of dosing openings distributed uniformly in the circumference and axially parallel. The circumferential spacing of such individual rows of dosing openings is adapted to the positioning of the filling position, the discharge position and possibly further positions, such as a test position, a cleaning position and the like. Thereby, it is achieved that, during the filling of one row of dosing openings, another row of dosing openings is simultaneously subjected to a check, emptying or cleaning. Thus, in each of such clock-controlled processes, a row of axially parallel dosing openings is always subjected to the respective process step in its entirety.

[0006] Such drum dispensers are particularly suitable for the dispensing of small doses, in which, as with the associated rows of dispensing openings, the target containers can be positioned in axially parallel rows at the discharge position. Such drum dispensing has now also been proven for difficult-to-dispense powders. However, for high-speed filling machines with high capacities, it is sought to achieve a multiple-row, usually two-row, arrangement of target containers. For example, in a capsule filling machine in which capsule lower parts of a plug-in capsule are used as target containers, a two-row format carrier with two rows of, for example, 2 x 12 capsule lower parts is used. With drum fillers known from the prior art, only one of the rows can be filled in the filling beat. A second drum filler, a second dispensing station and, if necessary, a second filling beat are then required in such applications.

[0007] In addition to the increased investment requirement, there is also an inconsiderable requirement for structural space, which can only be provided with difficulty under the narrow conditions of a filling machine. SUMMARY

[0008] It is an object of the present application to improve a drum dispenser of this type in such a way that a multiple-row arrangement of target containers can be filled simultaneously with metered dispensing quantities.

[0009] This object is achieved by a drum dispenser for producing individual dispensing quantities of a powdery product, comprising a product reservoir arranged in a filling position, a dispensing drum and a rotational drive for the dispensing drum, wherein the dispensing drum has dispensing openings distributed in the peripheral direction, wherein at least two dispensing openings spaced apart from one another in the peripheral direction of the dispensing drum are combined into a common dispensing section, and wherein the rotational drive is designed for a clock-controlled rotation of the dispensing drum about an axis of rotation in such a way that the individual dispensing sections with the associated dispensing openings are periodically at least in the filling position and in the discharge position.

[0010] It is provided in accordance with the application that at least two dispensing openings spaced apart from one another in the peripheral direction of the dispensing drum are combined into a common dispensing section. Here, the rotational drive is designed for a clock-controlled rotation of the dispensing drum about an axis of rotation in such a way that the individual dispensing sections with their associated dispensing openings spaced apart in the peripheral direction are periodically at least in the filling position and in the discharge position.

[0011] The arrangement according to the application allows that more than one row and in particular two rows of target containers can be filled with a single roller doser within a single work cycle. In comparison with single-row arrangements, no additional structural space is required and no additional time requirement is necessary. Thereby, the proven means of a roller doser can now also be used without restriction in filling machines with high productivity and process speed and thus can in particular exploit its advantages when dosing powders which are difficult in this respect.

[0012] It can be expedient for the dosing openings of the dosing section to be aligned radially with respect to the axis of rotation of the dosing roller, wherein these dosing openings then enclose a specific opening angle due to their circumferential spacing. This is different, however, in a preferred embodiment. Rather, the dosing section here has a central plane which extends radially with respect to the axis of rotation, wherein the dosing openings are arranged in pairs on both sides of the central plane. Here, the dosing openings have opening axes which are parallel with respect to one another and with respect to the central plane. In the case of the abandonment of the radial alignment of the opening axes, the mentioned parallelism results in that the dosing openings and the target containers to be filled can be precisely aligned with one another and the discharged dosing quantities target precisely the target containers assigned to them.

[0013] The product reservoir opens towards the dosing roller at the filling position by means of the output opening. Here, the output opening advantageously has a width in the circumferential direction which spans the dosing openings which are spaced apart from one another in the circumferential direction. It can be achieved thereby that, similar to the previously described multiple-row filling of target containers, also multiple rows of dosing openings of a single dosing section can be filled in only one work cycle.

[0014] Expediently, two agitators for the product are arranged in the product reservoir adjacent to the output opening and spaced apart from one another in the circumferential direction. In an advantageous refinement, the two agitators have agitator axes which are parallel with respect to one another and with respect to the axis of rotation and can be driven counter to one another here. Thereby, the circumferentially spaced dosing openings located immediately thereat achieve a fluidization of the powder reserve, so that a uniform filling of the dosing openings can be expected.

[0015] The input of the powdery product into the dosing openings and its discharge and transfer into the target containers can also be realized mechanically and / or by means of gravity. In a preferred embodiment, the respective dosing openings are defined on the inside by means of a filter element and can be connected to a negative pressure source through the filter element. Advantageously, as an alternative or in addition to the negative pressure source, the dosing openings can be connected to an overpressure source through the filter element. By suction of the powder, the negative pressure allows a uniform filling of the dosing openings and prevents premature dropping. By using an overpressure, it is possible to achieve a complete blowing out of the powder quantity without leaving a residual quantity, resulting in a high process reliability with a repeatable measurement of the dosing quantity in the target containers. BRIEF DESCRIPTION OF DRAWINGS

[0016] Embodiments of the application are described in more detail below on the basis of the drawings. Therein: Figure 1 A drum doser is shown in a schematic and cutaway perspective view with a total of four dosing segments that are uniformly distributed in the circumference and with two columns of dosing openings within each dosing segment. DETAILED DESCRIPTION

[0017] Figure 1 A drum doser 3 is shown in a schematic and perspective cross-sectional view when producing individual dosing quantities 2 of a powdery product 1 and when transferring such individual dosing quantities 2 into target containers 21, 21'. The powdery product is here a pharmaceutical powder. However, the powdery product can also be a powder-shaped nutritional supplement or the like. The target containers 21, 21' are here capsule lower parts of a plug-in capsule that, after filling, are also closed with a plugged-in capsule upper part. However, as target containers 21, 21' also transparent plastic covers or other containers are considered.

[0018] The drum doser 3 comprises a product reservoir 4, a dosing drum 5 and here only schematically shown a rotational drive M for a clock-controlled rotational movement of the dosing drum 5 around a rotational axis 19 in the rotational direction indicated by the arrow 28. The rotational drive M can be a stepper motor or, in particular, a servo motor. Other suitable rotational drives M can also be considered.

[0019] The dosing drum 5 extends along a longitudinal axis which is identical to the rotation axis 19 mentioned above and is substantially cylindrically configured with respect to this longitudinal axis. In the circumferential direction and distributed over the circumference, the dosing drum 5 has a plurality of dosing openings 7, 7'. At least two dosing openings 7, 7' which are spaced apart from one another in the circumferential direction U of the dosing drum 5 join to form a common dosing section 12. In the preferred embodiment shown, the dosing drum 5 is provided with a plurality, here a total of four, dosing sections 12 which are uniformly distributed over the circumference. Thus, the four dosing sections 12 are positioned at the same angular spacing, i.e. at 90°, with respect to one another in the circumferential direction around the rotation axis 19.

[0020] Each of these dosing sections has at least two dosing openings 7, 7' which are spaced apart from one another in the circumferential direction U. In other words, each dosing section 12 has at least one first dosing opening 7 and at least one second dosing opening 7' which are not at the same position in the circumferential direction U, but are in circumferential spacing with respect to one another. It is possible for the two dosing openings 7, 7' to have an offset with respect to one another in the direction of the longitudinal axis or in the direction of the rotation axis 19. In this context, the two dosing openings 7, 7' form a pair each, which is in spacing with respect to one another only in the circumferential direction U and not in the direction of the rotation axis 19. It is sufficient in the framework of the application for there to be only one pair of dosing openings 7, 7' in each dosing section 12. In the preferred embodiment shown, there are arranged in each dosing section 12 a plurality, here two, columns of dosing openings 7, 7' which are spaced apart from one another in the circumferential direction U. In other words, two or more, preferably three to twelve, first dosing openings 7 form a first opening column each, which extends axially parallel to the rotation axis 19. Analogously, two or more, preferably three to twelve, second dosing openings 7 form a second opening column each, which extends axially parallel to the rotation axis 19 and, in addition, parallel to the first column of first dosing openings 7 with a spacing measured in the circumferential direction U.

[0021] The dosing openings 7, 7' have an opening axis a, a' respectively. The opening axes a, a' can be arranged radially with respect to the rotation axis 19. However, in this context, they are parallel with respect to one another and also with respect to a center plane E, wherein the center plane E is spanned by a radial direction R which extends centrally through the respective dosing section 12 and the rotation axis 19. In addition, the opening axes a, a' are perpendicular to the rotation axis 19, viewed in projection onto the center plane E.

[0022] The dosing drum 5 has a centrally located clamping core 10 and a drum circumference 9 which surrounds the clamping core 10 at a radial distance. The dosing openings 7, 7' are configured as radially penetrating holes with a circular contour in the drum circumference 9. However, other contour shapes can also be suitable. The contour can be, for example, only partially circular, oval, polygonal, rectangular or square. The dosing openings 7, 7' open radially outward, i.e. at the outside 29 of the drum circumference 9. Radially inward, i.e. at the inside 30 of the drum circumference 9, the dosing openings are each defined by means of a filter element 8 which corresponds in size and shape to the cross section of the respective dosing opening 7, 7' and forms the bottom of the dosing opening.

[0023] Between the clamping core 10 and the drum circumference 9, a filter strip 11 is arranged. The filter strip 11 is provided for each dosing section 12. The filter elements 8 are jointly formed by an arc of suitable filter material which is wound around the clamping core 10 with the filter strip 11. Bonded filter elements 8 can also be used. The filter strip 11 is clamped radially outward by a clamping cone, not shown, with interposed filter material against the inside 30 of the drum circumference 9.

[0024] In the filter strip 11, a bifurcated pressure channel 14 is respectively configured which penetrates through the filter element 8 into the respective dosing opening 7, 7'. The pressure channel 14 of each filter strip 11 can be loaded with a desired pressure independently of the pressure channels 14 of the other filter strips 11 in the manner described in more detail below. By this and through the respective filter element 8, the dosing openings 7, 7' are also loaded with this pressure. The same pressure is set in all dosing openings 7, 7' of the respective dosing section 12, but independently of the pressure in the dosing openings 7, 7' of the respective other dosing sections 12.

[0025] The dosing drum 5 is rotatably supported about a rotation axis 19. In operation, the dosing drum is rotated by means of a rotation drive M in the direction of the arrow 17 in a clock-controlled manner such that the individual dosing sections 12 are periodically in a filling position I above the direction of gravity and in a discharge position III below the direction of gravity in at least two beats. In the shown embodiment, the individual dosing sections 12 together with their paired dosing openings 7, 7' periodically run through four different positions in four beats, starting with the filling position I above, followed by a first intermediate position II. This is followed by the discharge position III below and a second intermediate position IV, after which the cycle starts anew at the filling position I above.

[0026] In the upper filling position I, a product reservoir 4 is present in which a sufficient reserve of the powdered product 1 to be dosed is prepared. There, in the case of the formation of a corresponding dosing quantity 2 from the product reservoir 4, the powdered product 1 is filled into the corresponding first dosing openings 7 and the corresponding second dosing openings 7" of the associated dosing segments 12. For this purpose, the product reservoir 4 is open at the filling position I by means of an output opening 22 towards the dosing drum 5. The output opening 22 has a width b in the circumferential direction U which spans the dosing openings 7, 7" of the dosing segments 12 currently located there which are spaced apart from one another in the circumferential direction U. In the region of the boundaries of the output opening 22, a first column of dosing openings 7 is present, while in the region of the opposite boundaries of the output opening 22 in the circumferential direction U, a second column of dosing openings 7" is present. Thus, all dosing openings 7, 7" of the dosing segments 12 currently located there are in contact with the powdered product 1 prepared in the product reservoir 4 and are simultaneously filled therewith in one work cycle.

[0027] In order to support the filling process, the product reservoir 4 is provided with optional agitation means. The agitation means comprise, immediately adjacent to the output opening 22, two agitators 23, 25 which are spaced apart from one another in the circumferential direction U and which are completely inserted into the powdered product 1. The two agitators 23, 25 have agitator axes 24 which are parallel with respect to one another and also parallel with respect to the axis of rotation 19. The arrows 33, 34 indicate that the two agitators 23, 25 are driven counter to one another in operation and more precisely so that the two agitators move away from one another on their lower sides which face the dosing drum 5. Thereby it is achieved that the powdered product 1 is moved outwards to the boundaries of the output opening 22 which are opposite one another in the circumferential direction U or in the direction of rotation 28, i.e. to the positions in which the dosing openings 7, 7" of the dosing segments 12 currently located there are located.

[0028] Optionally, a further agitator 31 can also be provided above the two agitators 23, 25, which is arranged centrally in the product reservoir here and has an agitator axis 32. Furthermore, the product reservoir 4 is provided with a level sensor 6 in order to ensure a uniform filling process, by means of which the current filling level of the product 1 in the product reservoir is determined and by means of which a refilling of the product can be initiated as part of a control or regulation process for achieving a sufficiently uniform filling level in the product reservoir 4.

[0029] By means of the clock-controlled rotational movement, the thus far filled dosing section 12 continues to move in the rotational direction 28. Here, a scraper 27, which is not rotated together, is coupled behind the product reservoir 4 in the rotational direction 28 and placed on the rotationally forward-moving outer side 29 of the dosing drum 5 by means of spring pretension, removes product residues that can be attached at the outer side 29. In an optional first rotational beat, the filled dosing section 12 reaches a subsequent optional first intermediate position II, where, for example, a filling level control can be carried out.

[0030] After a further clock-controlled rotational movement, the mentioned dosing section 12 reaches the lower discharge position III. There, the dosing quantity 2 is discharged from all first dosing openings 7 and all second dosing openings 7' of this dosing section 12 and supplied to the target containers 21, 21'. To this end, the target containers 21, 21' are correspondingly arranged in terms of quantity and position to the dosing openings 7, 7': the first target containers 21 are arranged in a first column parallel to the rotational axis 19. The second target containers 21' are arranged in a second column parallel to the rotational axis 19 and also parallel to the first column of first target containers 21. In the circumferential direction U, they have a spacing to one another which corresponds to the spacing between the first dosing openings and the second dosing openings 7, 7'. In the direction of the rotational axis 19, the spacing between the target containers 21, 21' also corresponds to the spacing between the dosing openings 7, 7'. In the actual embodiment shown, the target containers 21, 21' are held as capsule lower parts in two columns in a capsule lower part holder 35 of a capsule filling machine. In the lower discharge position III, the opening axes a, a' of the dosing openings 7, 7' are aligned with the associated target containers 21, 21'. Due to the parallelism of the opening axes a, a' to one another, the discharged dosing quantities 2 precisely enter the set target containers 21, 21'.

[0031] At the discharge position III, it is also possible to arrange a here not shown measuring device, in particular a capacitive measuring device, between the dosing drum 5 and the target containers 21, 21', for a mass determination of the individual dosing quantities 2. Such a capacitive measuring device is also referred to as "Advanced Mass Verification System" or AMV system. Thereby, for each falling-through dosing quantity 2 it can be checked whether the volumetric dosing has actually resulted in the desired target mass within certain tolerances. In this way, density fluctuations in the powder, incompletely filled or empty dosing openings 7, 7', etc. can be identified.

[0032] The now emptied dosing section 12 subsequently continues to move to an optional second intermediate position IV and can be cleaned there, for example, by blowing.

[0033] As already mentioned above, the dosing openings 7, 7' can be loaded with the desired pressure through the respective filter element 8 when required. In the preferred embodiment shown, at least the dosing section 12 in the filling position I is selected with a negative pressure, and for this a connection for transmitting the negative pressure is established between the pressure channel 14 and a negative pressure source 15. The level of the negative pressure provided by the negative pressure source 15 is set by means of a schematically shown controller 18, which can be effected by a suitable control, if necessary, but also by adjustment. In any case, the negative pressure set to this extent is transmitted through the pressure channel 14 and the filter element 8 of the associated filter strip 11 into the dosing openings 7, 7' of the dosing section 12 in the filling position I above. The negative pressure sucks the pulverous product 1 from the product reservoir 4 into the dosing openings 7, 7'. The filter element 8 is designed in its permeability and in cooperation with the product 1 in such a way that the filter element, although air-permeable and thus also transmits pressure, the pulverous product 1 is inhibited and prevented from passing through. Thus, individual dosing quantities 2 of the pulverous product 1 are produced, which completely fill the dosing openings 7, 7' and whose volume corresponds to the volume of the respective dosing opening 7, 7'. Depending on the level of the negative pressure present and the properties of the product 1, in any case a specific degree of compression of the product 1 in the dosing openings 7, 7' is set, so that from the pre-defined volume of the dosing openings 7, 7' also a specific mass of the individual dosing quantities 2 results.

[0034] The applied negative pressure can be maintained at the same or a reduced level in the first intermediate position II and up to the discharge position III in order to prevent the dosing quantities 2 from falling prematurely from the dosing openings 7, 7'. However, the negative pressure loading is ended at the latest when the discharge position III below is reached. Instead, the dosing openings 7, 7' of the dosing section 12 in the discharge position III are now loaded with an overpressure through the filter element 8. For this, a connection for transmitting the overpressure is established between the pressure channel 14 of the associated filter strip 11 and an overpressure source 16. As in the previously mentioned case of the negative pressure source, the level of the overpressure provided by the overpressure source 16 is set by means of a schematically shown controller 18. The overpressure set to this extent is transmitted through the pressure channel 14 and the filter element 8 into the dosing openings 7, 7' of the dosing section 12 in the discharge position III below. The overpressure blows the dosing quantities 2 out of the dosing openings 7, 7'. In addition, the overpressure loading can also be used in the subsequent second intermediate position IV for a cleaning process there of the emptied dosing openings 7, 7'.

Claims

1. A drum doser (3) for producing individual doses (2) of a powdery product (1), the drum doser comprising a product reservoir (4) arranged in a filling position (I), a dosing drum (5) and a rotary drive (M) for the dosing drum (5), wherein The dosing drum (5) has dosing openings (7, 7') distributed in the peripheral direction, characterized in that at least two dosing openings (7, 7') spaced apart from one another in the peripheral direction (U) of the dosing drum (5) are combined into a common dosing section (12), and the rotary drive (M) is designed for a clock-controlled rotation of the dosing drum (5) about the axis of rotation (19) such that the individual dosing section (12) with the associated dosing openings (7, 7') is periodically at least in the filling position (I) and in the discharge position (III).

2. Dosing drum according to claim 1, characterized in that In the dosing section (12) two rows of dosing openings (7, 7') spaced apart from one another in the peripheral direction (U) are arranged.

3. Dosing drum according to claim 1, characterized in that The dosing section (12) has a central plane (E) extending in the radial direction relative to the axis of rotation (19), wherein the dosing openings (7, 7') are arranged in pairs on both sides of the central plane (E), and wherein the dosing openings (7, 7') have opening axes (a, a') which are parallel to one another and to the central plane (E).

4. Dosing drum according to claim 1, characterized in that The product reservoir (4) opens towards the dosing drum (5) in the filling position (I) by means of an output opening (22), wherein the output opening (22) has a width (b) in the peripheral direction (U) which spans the dosing openings (7, 7') spaced apart from one another in the peripheral direction (U).

5. Dosing drum according to claim 4, characterized in that In the product reservoir (4) two agitators (23, 25) spaced apart from one another in the peripheral direction (U) for the product (1) are arranged adjacent to the output opening (22).

6. Dosing drum according to claim 5, characterized in that The two agitators (23, 25) have agitator axes (24, 26) which are parallel to one another and to the axis of rotation (19) and can be driven opposite one another here.

7. Dosing drum according to claim 1, characterized in that Each dosing opening (7, 7') is defined on the inside by means of a filter element (8) and can be connected to a source of underpressure (15) through the filter element (8).

8. Dosing drum according to claim 1, characterized in that Each dosing opening (7, 7') is defined on the inside by means of a filter element (8) and can be connected to a source of overpressure (16) through the filter element (8).

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