Rotary press

Abstract

The invention relates to a rotary press comprising a rotor rotatable by means of a rotary drive, wherein the rotor has an upper punch guide (18) for upper press punches (14) and a lower punch guide (20) for lower press punches (16), as well as a die disk (10) arranged between the punch guides (18, 20), wherein the press punches (14, 16) interact with cavities (12) of the die disk (10), wherein the rotary press further comprises a filling device (26) by which material to be pressed is filled into the cavities (12) of the die disk (10), and wherein the rotary press comprises a pressure device (34) with an upper pressure unit (40) and a lower pressure unit (42), which, in operation with the upper press punches (14) and with the lower press punches (16), compress the material to be pressed into the cavities (12) of the die disk (10) to form pressed pellets. (48) cooperate,and wherein the rotary press has an ejection device (44) for ejecting pressables (48) produced in the rotary press, wherein a discharge device is provided downstream of the filling device (26) in the direction of rotation of the die disk (10), which discharges press material located on the upper side of the die disk (10) rotating relative to the discharge device from the die disk (10), wherein the discharge device is designed such that it discharges press material located on the die disk (10) outwards from the die disk (10), and wherein a return device is provided which is designed such that it receives the press material discharged by the discharge device and feeds it back to the filling device (26),

Description

[0001] The invention relates to a rotary press comprising a rotor rotatable by means of a rotary drive, wherein the rotor has an upper punch guide for upper press punches and a lower punch guide for lower press punches, as well as a die disc arranged between the punch guides, wherein the press punches interact with cavities of the die disc, wherein the rotary press further comprises a filling device by which material to be pressed is filled into the cavities of the die disc, wherein the rotary press comprises a pressure device with an upper pressure unit and a lower pressure unit which, in operation, interact with the upper press punches and with the lower press punches to compress the material in the cavities of the die disc into pellets, and wherein the rotary press has an ejection device for ejecting pellets produced in the rotary press.wherein, in the direction of rotation of the die disk, a discharge device is provided downstream of the filling device, which discharges the pressing material located on the upper side of the die disk rotating relative to the discharge device from the die disk.

[0002] Rotary presses typically incorporate a multitude of upper and lower press rams, each pair assigned to a cavity of a die. During operation, the upper and lower press rams rotate together with the die, their axial movement controlled by cams and guided by upper and lower ram guides. As the press rotates, the die passes through various components of the rotary press: a filling unit, where the material to be compressed, particularly powdered material, is filled into the cavities of the die; and a compression unit, where the upper and lower press rams are typically pressed into the cavities by upper and lower pressure rollers to compress the material into pellets, such as tablets.Following the pressing mechanism, the upper press rams are moved upwards out of the cavities, and the pellets produced in the cavities are pushed by the lower press rams onto the top of the die plate. Such rotary presses also include an ejection device for removing the pellets produced in the press. The ejection device directs the pellets to a first or second pellet run. The first pellet run, for example, could be for pellets identified as good. The second pellet run, for example, could be for pellets identified as defective.

[0003] When filling the cavities of a die disc in a rotary tablet press, the lower press rams are first moved downwards by means of cam elements until slightly more material is placed in the cavity than is needed to press a tablet. The lower press rams are then moved upwards by a specific amount, again by means of cam elements, so that precisely the required amount of material remains in the cavity to press the desired tablet. A small amount of excess material is forced upwards from the cavity. This excess material is typically removed from the top of the die disc by a scraper.

[0004] A pneumatic scraper is known, for example, from DE 10 2013 006 950 B3. According to one embodiment, the scraper can completely remove excess tablet material from the die disc to the outside. In another embodiment, excess tablet powder can be reused by returning it to the filling device. In this embodiment, a groove is located radially within the partial circle formed by the cavities in the die disc. This groove collects the tablet material scraped inwards by the scraper and transports it back to the filling device for reuse. The scraper device described in DE 10 2013 006 950 B3 comprises a force-generating device that presses the scraper against the top surface of the die disc with a predetermined contact force. For this purpose, the force-generating device includes a fluid cushion filled with a fluid.

[0005] The material being transported back to the filling unit from the die disc's trough moves approximately 360° along the die disc's direction of movement before being returned to the filling unit. Due to the considerable centrifugal forces that occur, particularly in high-performance rotary presses, material can be lost from the trough and distributed undesirably within the press. Furthermore, the trough only allows for the return of one type of material at a time. For example, when compressing two different materials into two-layer tablets, only material from one layer, such as the second layer, can be returned to the filling unit, while excess material from the second layer is lost as rejects.

[0006] Based on the prior art described above, the invention aims to provide a rotary press of the type mentioned at the outset, which enables improved recycling of excess pressing material with less material loss.

[0007] The invention solves the problem through the subject matter of independent claim 1. Advantageous embodiments can be found in the dependent claims, the description and the figures.

[0008] For a rotary press of the type mentioned above, the invention solves the problem by designing the discharge device in such a way that it discharges the pressing material located on the die disc outwards from the die disc, and by providing a return device which is designed to receive the pressing material discharged by the discharge device and feed it back to the filling device.

[0009] The basic structure of the rotary press, as described in the present invention, has been explained at the outset. As explained, the upper and lower ram guides direct the press rams during their axial movement. The ram heads interact with cam tracks that move the press rams axially as they rotate with the rotor, in particular towards and away from each other. The cam tracks are generally composed of several cam track elements. They can accommodate the ram heads in corresponding guide receptacles or simply bear against a mirror surface of the ram heads. The pressure device generally comprises an upper pressure roller and a lower pressure roller, which interact with the ram heads of the upper and lower press rams, respectively. Multiple pressure devices of this type can also be provided, for example, pre-pressure devices and main pressure devices.The ejector cam, as part of the control cams, moves the lower press rams upwards after the pellets have been formed in the respective cavity, so that the pellets reach the top of the die plate, from where they can be conveyed to a first or second pellet run. The material being pressed is typically powdery. The pellets can be tablets. The rotary press can therefore be a rotary tablet press. The tablets can be, for example, pharmaceutical tablets.

[0010] The rotary press according to the invention comprises, in a manner known per se, a discharge device arranged downstream of the filling device and, in particular, upstream of the pressure device in the direction of rotation of the die disc. This discharge device removes excess material located on the upper surface of the die disc from the upper surface before it is compressed in the pressure device. According to the invention, the discharge device guides the material located on the die disc radially and / or tangentially outwards from the die disc with respect to the axis of rotation of the die disc. The material can be discharged, for example, at an angle of less than 10°, for example, approximately 5°, to the radial axis. Furthermore, according to the invention, a return device is provided that receives the material discharged outwards from the die disc by the discharge device and feeds it back to the filling device.By arranging the discharge device between the filling device and the pressing device, and directing the material to the outside of the return device, which in turn feeds the material to the filling device fixed on the outer side of the rotating die disk, the excess material is returned directly to the filling device. In particular, unlike in the prior art, the material does not have to complete a nearly full rotation with the die disk before being returned to the filling device. This avoids the material losses and potential contamination inside the rotary press caused by centrifugal force that are common in the prior art.In contrast to the prior art method of product return via the inside of the die disc, the invention advantageously utilizes the centrifugal force occurring during operation to assist the outward discharge of the compressed material. This improves the efficiency of the discharge and product return to the filling unit. Furthermore, in rotary presses for the production of multilayer tablets and the successive layer-by-layer compression of different compressed materials, the invention enables separate return of different compressed materials to their respective filling units.

[0011] A sensor can be provided to monitor the proper functioning of the discharge and / or return system. This ensures that a malfunction of the discharge and / or return system does not lead to an undesirable backup of material or the unwanted entry and retention of material in the pressing chamber. Significant product loss can thus be avoided.

[0012] According to a particularly practical embodiment, the discharge device can be a scraping device comprising a scraper, wherein the scraper is arranged above the die disc such that it scrapes the pressing material located on the die disc outwards from the die disc. The scraper can be arranged directly above the die disc or in contact with its upper surface, with the die disc rotating beneath the scraper. The scraper can also be pressed onto the upper surface of the die disc, for example by a force-generating device, in particular a pneumatic force-generating device, as described, for example, in DE 10 2013 006 950 B3.

[0013] The return system can include a receiving container that collects the material removed from the die disc, for example, the stripped material, and from which the material is fed back to the filling device. However, it is also possible for the removed material to be fed directly to the filling device without an intermediate receiving container.

[0014] The return system can also include a return channel through which the compressed material is fed back to the filling device. The return channel can be connected to the receiving hopper. The return channel can be closed or open. For example, it can be designed as a return trough. Furthermore, the return channel can be rigid or flexible. For example, it could be a return hose.

[0015] In a further configuration, the return system can include conveying means for transporting the pressed material to the filling unit and / or within the filling unit to a filling chamber. These conveying means can, for example, include pneumatic conveying devices. In particular, it is possible for the conveying means to include a Venturi nozzle. Vacuum conveying of the pressed material using a vacuum conveying device is also possible. The pressed material discharged from the die disc by the discharge device can be fed to the filling unit in a controlled and rapid manner by the conveying means. Pneumatic conveying devices, including, for example, a Venturi nozzle, can accelerate the pressed material towards the filling unit. This achieves a particularly safe and reliable return of the pressed material to the filling unit in a structurally simple manner.

[0016] In a further configuration, the conveying means can include a screw conveyor. Conveying means, such as a screw conveyor, can be arranged, for example, in a centrifugal or cyclone separator and / or within a filling pipe of the filling device leading to a filling chamber. The conveying means can also include a suction device that conveys the pressed material to the filling device and / or to a filling chamber within the filling device by means of negative pressure. Particularly when product return is achieved by a suction device, especially if it is solely achieved by a suction device, and especially when using a cyclone separator, a screw conveyor can be additionally used to prevent pressed material from being accidentally drawn from a filling chamber, particularly a dosing chamber. The screw conveyor then acts as a gate.

[0017] The conveying system ensures reliable conveying of the filling material even at high speeds of the rotary press.

[0018] The return system can also include a separating device for separating the pressed material from a conveying fluid. The separating device can also decelerate the pressed material, which may have been previously accelerated, for example, by pneumatic conveying means. The conveying fluid can be a conveying gas, such as conveying air.

[0019] In a particularly practical design, the separation device can include a centrifugal separator and / or a cyclone separator. Using a centrifugal separator, also known as an inertial separator, or a cyclone separator, comprising in particular a cyclone funnel, the material being returned to the filling device can be separated from the conveying gas transporting the material in a particularly reliable manner before, for example, it is fed into a filling chamber of the filling device.

[0020] In a further embodiment, the filling device may include a filling reservoir and a filling chamber located below the filling reservoir, with a filling wheel rotating within it. The return mechanism feeds the pressed material below the filling reservoir into a connecting section leading to the filling chamber and / or directly into the filling chamber of the filling device. The filling chamber may also serve as a metering chamber for the filling device. The filling wheel may accordingly be a metering wheel.

[0021] The return system can feed the pressed material particularly close to the axis of rotation of the filling wheel. This axis of rotation can be formed by a hub of the filling wheel. The return system can feed the pressed material directly adjacent to the hub of the filling wheel that forms the axis of rotation. By returning the pressed material as close as possible to the axis of rotation of the filling wheel, the system takes advantage of the fact that the back pressure of the pressed material already circulating in the filling chamber is as low as possible. The back pressure increases from the axis of rotation to the outer diameter of the filling chamber due to the centrifugal force generated by the circulation. The lower back pressure allows for recirculation into the filling chamber, especially the metering chamber downstream of a first filling chamber in the direction of rotation of the die disc, without product buildup. Such product buildup would otherwise prevent effective recirculation of the pressed material into the filling chamber.Furthermore, it is exploited that, due to centrifugal force, the pressing material already in the filling chamber tends to collect in the outer area of ​​the filling chamber anyway, so that in the central area of ​​the filling chamber, in the area of ​​the axis of rotation, an area with less pressing material is created, which simplifies the return of pressing material to this area.

[0022] In a further embodiment, the return system can have a return section opening into the filling chamber, and a barrier can be arranged in the filling chamber upstream of the filling wheel, in the direction of rotation of the filling wheel, creating a free space below the opening of the return section that is not filled with pressing material. Thus, a barrier is introduced in the upper area of ​​the filling chamber, particularly the metering chamber, directly upstream of the opening of the return section, in the direction of rotation of the filling or metering wheel. This barrier prevents the filling chamber from being completely filled in height in the area of ​​the opening of the return section. An open space is therefore actively created, allowing the additional flow of pressing material through the return section.

[0023] The filling reservoir, which may be designed as a filling hopper, contains the material to be compressed in the rotary press. From the filling reservoir, the material flows, primarily by gravity, into a filling chamber located below the reservoir. This filling chamber typically contains a filling wheel, which is driven by rotation during operation of the filling device. The filling wheel may, for example, have several blades. It serves to loosen and distribute the material, particularly to prevent product buildup or bridging. The filling wheel can also ensure more even filling of the cavities, thus improving the efficiency of the process. The filling device may have multiple filling chambers, each containing a rotating filling wheel. At least one filling chamber may be a metering chamber with a metering wheel driven by rotation within it.The return system can then feed the material being pressed near a rotational axis of the metering wheel. By feeding the material being pressed into a connecting section leading from the filling reservoir to the filling chamber and / or directly into a filling chamber of the filling device, particularly near a rotational axis of a filling wheel driven to rotate within the filling chamber, an additional suction effect can be generated on the material being pressed due to the influence of centrifugal force. This enables the material to be returned to the filling device and conveyed away via the return system, especially at even higher rotational speeds of the rotor or die disc of the rotary press of more than 60 revolutions per minute, preferably more than 80 revolutions per minute, for example up to 120 revolutions per minute.

[0024] In a further embodiment, it may be provided that the rotary press also includes a second filling device through which the second pressing material to be pressed is filled into the cavities of the die disc, and that the rotary press also includes a second pressure device, with a second upper pressure unit and a second lower pressure unit, which in operation cooperate with the upper press rams and with the lower press rams to press the second pressing material or the first and second pressing material into the cavities of the die disc to form pressed pieces.

[0025] Like the first pressing material, the second pressing material is also primarily in powder form. A rotary press with two filling units and two pressing units can be used, for example, to produce two-layer tablets by successively compressing different pressing materials layer by layer. If the rotary press has two ejection units, the simultaneous production of single-layer tablets in double rotary operation is also possible. In this case, only half of the rotor is used for the production of each tablet. However, as explained at the outset, the invention offers a particular advantage when different pressing materials are filled into the cavities of the first and second filling units and then compressed by the first and second pressing units, respectively.

[0026] In a further embodiment, a second discharge device may be provided downstream of the second filling device in the direction of rotation of the die disc. This discharge device removes the second pressing material located on the upper surface of the rotating die disc relative to the discharge device. The second discharge device is designed to remove the second pressing material located on the die disc outwards. A second return device is also provided, arranged to receive the second pressing material removed by the second discharge device and return it to the second filling device. Thus, in two-shift operation of the rotary press, the pressing materials from both shifts can be returned separately to their respective filling devices.The second discharge device and the second return device can, in principle, be designed in the same way as the first discharge device and the first return device.

[0027] Alternatively, it is also possible that a second discharge device is provided downstream of the second filling device in the direction of rotation of the die disk, which discharges the second pressing material located on the top of the die disk rotating relative to the discharge device from the die disk, wherein the second discharge device is designed in such a way that it discharges the second pressing material located on the die disk inwards into a return channel formed radially within the cavities in the die disk.In this case, only one of the pressing materials is fed directly to the filling device in the manner according to the invention. The second pressing material, which is usually filled subsequently in the direction of rotation of the die disk, can then be fed back to the second filling device via a return channel, for example a return trough, formed radially within the pitch circle of the cavities in the die disk, as explained above regarding the prior art. The second pressing material, fed radially and / or tangentially inwards into the return channel or return trough by the second discharge device with respect to the axis of rotation of the die disk, can rotate back to the second filling device with the die disk in the return channel and be received by the second filling device again.The second discharge device can also be designed as a scraper device, comprising a scraper which in this case scrapes the excess pressing material inwards.

[0028] Of course, it is also possible, for example, for the second pressing material to be conveyed outwards from the die plate by the second discharge device without being fed back into the second filling device. According to this design, the excess pressing material can therefore be conveyed out of the rotary press.

[0029] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. They schematically show: Fig. 1 shows a rotary press according to the invention in an unwound view of the rotor, Fig. 2 shows a part of the Figure 1The rotary press shown, with a discharge device and return device according to the invention, is shown in a perspective view in Fig. 3, based on a first embodiment. Figure 2 with partially exposed recirculation device, Fig. 4 a part of the in Figure 1 The rotary press shown, with a discharge device and return device according to a further embodiment, is shown in a perspective view, Fig. 5 a partial sectional view along line AA in Figure 4 , Fig. 6 a partial sectional view along line BB in Figure 4 , Fig. 7 a filling device as well as a discharge device and a return device according to a further embodiment in a side view, and Fig. 8 a sectional view along line CC in Figure 7 .

[0030] Unless otherwise stated, the same reference symbols in the figures denote the same objects.

[0031] The in Figure 1The rotary press shown according to the invention is a rotary press for tablet production in which powdered pressing material is compressed into tablets. The rotor of the rotary press is driven by a rotary drive and comprises a die disk 10 having a plurality of cavities 12. The cavities 12 can, for example, be formed by bores in the die disk 10. The rotor further comprises a plurality of upper press rams 14 and lower press rams 16, which rotate synchronously with the die disk 10. The upper press rams 14 are axially guided in an upper ram guide 18, and the lower press rams 16 are axially guided in a lower ram guide 20. The axial movement of the upper press rams 14 and lower press rams 16 during the rotation of the rotor is controlled by upper control cam elements 22 and lower control cam elements 24.The control cam elements 22, 24 are held on a cam support of the rotary press. Furthermore, one is in . Figure 1 A filling device 26, shown only schematically, is provided, comprising a feed hopper 28, a first filling chamber 30, and a second filling chamber 31, the feed hopper 28 being connected to a filling tube 32. The second filling chamber 31 can form a metering chamber. In this example, pressing material thus flows from the feed hopper 28 via the filling tube 32, for example by gravity, into the filling chambers 30 and 31, and from these, via an outlet provided on the underside of the filling chambers 30 and 31, again for example by gravity, into the cavities 12 of the die disk 10.

[0032] The rotary press also includes a pressure unit 34. The pressure unit 34 comprises a pre-pressure unit with an upper pre-pressure roller 36 held on an upper support 35 and a lower pre-pressure roller 38 held on a lower support 37, as well as a main pressure unit with an upper pressure roller 40 held on an upper support 39 and a lower pressure roller 42 held on a lower support 41. Furthermore, the rotary press includes an ejection unit 44 with an ejection element 46. The ejection element 46 strips tablets 48, conveyed by the lower press rams 16 onto the upper surface of the die 10, from the die 10 and conveys the tablets 48 to a first pellet discharge 50. The rotary press also includes a control unit 52 for controlling the operation of the rotary press. The rotary press also includes a Figure 1The second tablet feed (not shown in detail) is located upstream of the first tablet feed 50 in the direction of rotation of the die disk 10 and may, for example, be arranged parallel to it. Tablets can be selectively conveyed into the second tablet feed by means of a sorting device, comprising, for example, a sorting nozzle. The first tablet feed 50 can be for tablets identified as good, and the second tablet feed 50 for tablets identified as defective.

[0033] Based on the Figures 2 and 3A first embodiment of a discharge and return device according to the invention is described. The discharge device is designed in the form of a scraper, comprising a scraper 54 which, in the illustrated example, scrapes excess pressing material located on the upper side of the die disk 10 outwards from the die disk 10 into a receiving container 56 of the return device. The return device comprises pneumatic conveying means 58, in this case comprising a Venturi nozzle 58, which conveys pressing material located in the receiving container 56 via a return channel 60 of the return device to a separating device 62 for separating the pressing material from a conveying fluid, in particular conveying air.The separating device 62, which in this case is designed as a centrifugal separator 62, feeds the compressed material separated from the conveying air back to the filling device 26, in particular into the second filling chamber 31, and thus into the further tablet production process in the rotary press. A filling wheel, driven to rotate during operation, can be arranged in each of the filling chambers 30 and 31. The compressed material can be fed close to the axis of rotation of the filling wheel, which is arranged to rotate in the second filling chamber 31, in particular directly adjacent to a hub of the second filling chamber 31 that forms the axis of rotation.

[0034] In Figure 3For illustrative purposes, the cover of the separating device 62, designed as a centrifugal separator 62, has been removed. This reveals a separation channel 64 of the centrifugal separator 62, in which the material being pressed is separated from the conveying air by utilizing centrifugal force. In the example shown, the separation channel 64 branches into a conveying air channel 66, through which the conveying air is discharged from the centrifugal separator 62, and a material channel 68, through which the material being pressed, separated from the conveying air, is fed to the filling chamber 31.

[0035] Based on the Figures 4 to 6 A further embodiment of a discharge and return device according to the invention will be explained. This embodiment largely corresponds to the embodiment according to the Figures 2 and 3 . Thus, in the exemplary embodiment according to the Figures 4 to 6Excess pressing material is directed by the scraper 54 of the scraper device from the die disk 10 to the outside into a receiving container 56, from which it is fed by means of a Venturi nozzle 58 through a return channel 60 to a separating device 70 of the return device, which in this case is designed in the form of a cyclone separator 70, in particular a cyclone funnel 70.

[0036] The function of the cyclone separator 70 is shown in the sectional views of the Figures 5 and 6 explained in more detail. Figure 5 The inlet 72 of the cyclone separator 70, connected to the return channel 60, is visible. The pressing material, along with conveying air, is fed into the cyclone separator 70 through this inlet. As part of the cyclone separator 70's operation, the conveying air used as the transport medium is discharged upwards from the cyclone separator 70 via an air outlet 74, as shown in Figure 5This is illustrated by arrow 76. An extraction system can be connected to the air outlet 74 to assist in separating the compressed material from the conveying fluid. The extraction system can also remove any remaining dust from the powder. The compressed material, separated from the conveying air, passes from the funnel-shaped upper section of the cyclone separator 70 into an outlet channel 78, through which it is again fed to the filling device 26, in particular the second filling chamber 31, as shown in Figure 5 Illustrated by arrows 80, 82, and 84. In the sectional view of the Figure 6A rotating filling wheel 86 is also visible in the second filling chamber 31. The material being pressed is fed from the outlet channel 78 close to the axis of rotation 88 of the filling wheel 86, in particular directly adjacent to a hub of the filling wheel 86 that forms the axis of rotation. The centrifugal force generated by the rotation of the filling wheel 86 exerts a suction effect on the material being returned to the second filling chamber 31, thus facilitating the return of the material and the emptying of the cyclone separator 70. Furthermore, the centrifugal force causes the material to collect in the outer area of ​​the filling chamber 31, thereby facilitating the return of the material in the area of ​​the axis of rotation.

[0037] Based on the Figures 7 and 8 A further embodiment of the invention will be explained, which is largely the same as the embodiment according to the example above. Figures 4 to 6 corresponds. This is also the case in the embodiment according to the Figures 7 and 8A recirculation device in the form of a cyclone separator 70 is provided, whereby, for the sake of simplicity, the recirculation channel 60 and the receiving container 56 are not shown in detail. It is understood that the embodiment of the exemplary case described below is based on the Figures 7 and 8 also with the embodiment according to the Figures 2 and 3 , in particular it can be combined with the separating device 62 provided there.

[0038] In the cross-sectional view from below the Figure 8The first filling chamber 30, containing a rotating filling wheel 90, is visible. The axis of rotation of the filling wheel 90 is formed by its hub 92. Adjacent to the first filling chamber 30 is the second filling chamber 31, containing a rotating filling wheel 86. Again, the axis of rotation of the filling wheel 86 is formed by its hub 94. As explained, the second filling chamber 31 can be a metering chamber. The rotating filling wheel 86 in the second filling chamber 31 can accordingly be a metering wheel 86. The direction of rotation of the rotating filling wheel 86 in the second filling chamber 31 is shown in the view of the Figure 8clockwise, as illustrated by arrow 96. Immediately adjacent to the hub 94, which forms the axis of rotation of the filling wheel 86, a return section 98 of the return device opens into the second filling chamber 31 above the agitator blades of the filling wheel 86. Due to centrifugal force, any pressed material already present in the second filling chamber 31 collects in the outer area of ​​the second filling chamber 31 during operation, thus facilitating the return of the pressed material through the return section 98 in the area immediately adjacent to the hub 94. Furthermore, above the filling wheel 86, and in particular above the agitator blades of the filling wheel 86, a barrier 100 is arranged in the second filling chamber 31 in the direction of rotation of the filling wheel 86 and in front of the return section 98. This barrier forms a free space below the opening of the return section 98, which is not filled with pressed material and further facilitates the return of the pressed material through the return section 98. Reference symbol list

[0039] 10 Die disc 12 Cavity 14 Upper press ram 16 Lower press ram 18 Upper ram guide 20 Lower ram guide 22 Upper control cam element 24 Lower control cam element 26 Filling device 28 Feed hopper 30 First filling chamber 31 Second filling chamber 32 Filling tube 34 Pressure device 35 Upper bracket 36 Upper pre-pressure roller 37 Lower bracket 38 Lower pre-pressure roller 39 Upper bracket 40 Upper pressure roller 41 Lower bracket 42 Lower pressure roller 44 Ejection device 46 Scraper 48 Tablets 50 Tablet discharge 52 Control device 54 Scraper 56 Receiving hopper 58 Pneumatic conveying device / Venturi nozzle 60 Return channel 62 Separation device / Centrifugal separator 64 Separation channel 66 Conveying fluid channel 68 Pressing material channel 70 Separation device / cyclone separator / cyclone funnel 72 Inlet 74 Air outlet 76 Arrow 78 Outlet channel 80 Arrow 82 Arrow 84 Arrow 86 Filling wheel 88 Rotary shaft 90 Filling wheel 92 Hub 94 Hub 96 Arrow 98 Return section 100 Barrier

Claims

1. Rotary press comprising a rotor rotatable by means of a rotary drive, the rotor having an upper punch guide (18) for upper press punches (14) and a lower punch guide (20) for lower press punches (16), and a die disk (10) arranged between the punch guides (18, 20), the press punches (14, 16) interacting with cavities (12) of the die disk (10), the rotary press further comprising a filling device (26) by which material to be pressed is filled into the cavities (12) of the die disk (10), the rotary press comprising a pressure device (34) with an upper pressure unit (40) and a lower pressure unit (42) which, in operation, act with the upper press punches (14) and with the lower press punches (16) to compress the material to be pressed into the cavities (12) of the die disk (10) to form pressed products. (48) cooperate,and wherein the rotary press has an ejection device (44) for ejecting pressables (48) produced in the rotary press, wherein a discharge device is provided downstream of the filling device (26) in the direction of rotation of the die disk (10), which discharges pressable material located on the upper side of the die disk (10) rotating relative to the discharge device from the die disk (10), , characterized by the fact that the discharge device is designed in such a way that it discharges the pressing material located on the die disc (10) outwards from the die disc (10), and that a return device is provided which is designed in such a way that it receives the pressing material discharged by the discharge device and feeds it back to the filling device (26).

2. Rotary press according to claim 1, characterized by the fact thatthe discharge device is a scraper device comprising a scraper (46), wherein the scraper (46) is arranged above the die disk (10) such that the scraper (46) scrapes pressing material located on the die disk (10) outwards from the die disk (10).

3. Rotary press according to one of the preceding claims, characterized by the fact that the return device comprises a receiving container (56) which receives the pressing material removed from the die disk (10) and from which the pressing material is fed back to the filling device (26).

4. Rotary press according to one of the preceding claims, characterized by the fact that The return device includes a return channel (60) through which the pressing material is fed back to the filling device (26).

5. Rotary press according to one of the preceding claims, characterized by the fact thatThe return conveying device (58) comprises conveying the press material to the filling device (26) and / or within the filling device (26) to a filling chamber of the filling device (26).

6. Rotary press according to claim 5, characterized by the fact that the funding (58) includes pneumatic funding (58).

7. Rotary press according to one of claims 5 or 6, characterized by the fact that the funding (58) includes a Venturi nozzle (58).

8. Rotary press according to one of claims 5 to 7, characterized by the fact that The conveying equipment includes a screw conveyor and / or a suction device.

9. Rotary press according to one of claims 5 to 8, characterized by the fact that the return device comprises a separation device (62, 70) for separating the pressing material from a conveying fluid, in particular conveying air, wherein the separation device (62, 70) preferably comprises a centrifugal separator (62) and / or a cyclone separator (70).

10. Rotary press according to one of the preceding claims, characterized by the fact that the filling device (26) has a filling reservoir (28) and a filling chamber (30, 31) arranged below the filling reservoir (28) with a filling wheel (86) driven to rotate therein, and that the return device feeds the pressing material below the filling reservoir (28) into a connecting section (32) leading to the filling chamber (30, 31) and / or into the filling chamber (30, 31) of the filling device (26).

11. Rotary press according to claim 10, characterized by the fact that the return device feeds the pressing material near a rotational axis (88) of the filling wheel (86), in particular directly adjacent to a hub (94) of the filling wheel (86) forming the rotational axis.

12. Rotary press according to one of claims 10 or 11, characterized by the fact thatthe return device has a return section (98) opening into the filling chamber (30, 31), and that above the filling wheel (86) in the direction of rotation of the filling wheel (86) a barrier (100) is arranged in the filling chamber (30, 31) in front of the return section (98), which forms a free space below the opening of the return section (98) that is not filled with pressing material.

13. Rotary press according to one of the preceding claims, characterized by the fact thatthe rotary press further comprises a second filling device by which the second pressing material to be pressed is filled into the cavities (12) of the die disc (10), and that the rotary press further comprises a second pressure device, with a second upper pressure unit and a second lower pressure unit, which in operation cooperate with the upper press punches (14) and with the lower press punches (16) to press the second pressing material or the first and second pressing material in the cavities (12) of the die disc (10) into pressed pellets (48).

14. Rotary press according to claim 13, characterized by the fact thatIn the direction of rotation of the die disk (10) downstream of the second filling device, a second discharge device is provided, which discharges the second pressing material located on the upper side of the die disk (10) rotating relative to the discharge device from the die disk (10), wherein the second discharge device is designed such that it discharges the second pressing material located on the die disk (10) outwards from the die disk (10), and that a second return device is provided which is arranged such that it receives the second pressing material discharged by the second discharge device and feeds it back to the second filling device.

15. Rotary press according to claim 13, characterized by the fact thatIn the direction of rotation of the die disk (10) downstream of the second filling device, a second discharge device is provided, which discharges the second pressing material located on the top side of the die disk (10) rotating relative to the discharge device from the die disk (10), wherein the second discharge device is designed such that it discharges the second pressing material located on the die disk (10) inwards into a return channel formed radially within the cavities (12) in the die disk (10).

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