WO2008104267A1

WO2008104267A1 - Rotary tablet press having a washing device

Info

Publication number: WO2008104267A1
Application number: PCT/EP2008/000900
Authority: WO
Inventors: Hans Krämer
Original assignee: Ima Kilian Gmbh & Co. Kg
Priority date: 2007-03-01
Filing date: 2008-02-06
Publication date: 2008-09-04
Also published as: DE202007003176U1

Abstract

The invention relates to a rotary tablet press having a rotor 10 comprising an upper punch guide ring 14 for an upper punch 16, a bottom punch guide ring 11 having guides for a bottom punch 13, and a matrix disk 17 disposed between the punch guide rings. The tablet press has a washing device, by means of which the rotor 10 can be washed using a washing fluid, and a working chamber 5 sealed in a fluid-tight manner is formed in the housing 5, wherein the working chamber can be filled with washing fluid for immersing the rotor into a washing bath. In order to minimize health risks for the staff, at least one ultrasonic transducer 70, 71 is associated with the working chamber 5 for applying ultrasound to the washing bath.

Description

Applicant: IMA KILIAN GmbH & Co. KG, Scarletallee 11, D-50735 Cologne, Germany Title: Rotary tablet press with washing device

The invention relates to a rotary tablet press with a housing, with a rotatably mounted in the housing rotor having a Oberstempelführungsring, a Unterstempelführungsring and arranged between the punch guide rings Matrizenscheibe, with a washing device, with which the rotor is washable by means of washing liquid, and with a in the housing trained, liquid-tight sealed working space, which can be filled with washing liquid for at least partial flooding of the working space and immersion of the rotor in a washing bath.

Rotary tablet presses with upper and lower punches, which are guided in associated punch guide rings and with which in the matrices of a die plate tablets such as drug tablets, detergent tablets od. In particular, can be made from powder, have long been known. The rotor driven by a suitable motor may, for example, have from about 8 up to 100 pressing stations, depending on the size and diameter of punch guide rings and die plate, and at speeds of e.g. revolve up to 150 rev / min. The upper and lower punches are here by means of suitable rollers or slide tracks moved up and down to make the production of the tablets in the matrices. In order to protect the guides for the punches, which are usually designed as sliding guides, against entering tablet dust, the upper and lower punches are assigned sealing elements which are disclosed as bellows, as disclosed, for example, in WO 02/064 356 A1, or as sealing collars with wiper lips, as disclosed in WO 03/084 738 Al, may be executed.

In newer generations of rotary tablet presses, these integrated washing devices are used with which the rotor and the entire working space in which the rotor is in operation can be cleaned with washing liquid. The integration of automatic washing devices allows short changeover times to a different tablet geometry with high operational reliability. The washing liquid is sprayed through nozzles with pressure of eg up to 6 bar in the working space and the surfaces of the stamp and the matrices or recordings for the matrices are cleaned with the washing liquid under pressure. Since all the parts coming into contact with the product to be produced are cleaned with the washing liquid, contamination of a subsequent batch can be prevented to the greatest possible extent and, at the same time, dangers to personnel are largely avoided in the case of harmful tablet dusts.

The object of the invention is to provide a rotary tablet press, which is provided with a washing device and the open after performing a Waschvorgangs- with the washing device without health hazards for staff and / or possibly even without further Nachreinigungsarbeiten for the production of tablets from others Starting materials can be used.

These and other objects are achieved by the invention defined in claim 1. In the rotary tablet press according to the invention a liquid-tight sealed working space is formed in the housing, which can be filled with washing liquid for immersing the rotor in a washing bath. The flooding of the working space with the washing liquid such as water has the advantage that the die plate, the punch heads, the dies, the underside of Oberstempelführungsrings and sealing elements that surround the punch shafts, therefore all coming into contact with the product to be pressed (powder) parts , wetted on all sides with the washing liquid and be lapped by this. By flooding and immersion in a washing bath in particular those portions of the sealing elements, which face the axis of rotation of the rotor, wetted with washing liquid and lapped. According to the invention, in the rotary tablet press it is provided that the cleaning effect of the washing bath is additionally increased by the use of ultrasound or ultrasound cleaning. In order to effect an ultrasonic cleaning, the working space according to the invention has at least one ul associated with ultrasonic transducer, which can be applied to all located in the washing bath parts of the rotor with ultrasound to enhance the cleaning effect of the wash bath.

Cleaning with ultrasound is far superior to manual cleaning methods and also to a cleaning method with spray nozzles alone, since the combination of washing bath and ultrasonic cleaning can also penetrate into areas which, in particular, can not be reached manually. In the ultrasonic cleaning, even stubborn dirt or encrustations on the surface of the washing bath washed parts can be solved. The sound waves generated by the at least one ultrasonic transducer propagate in the liquid medium of the washing bath in the form of a longitudinal wave, which causes periodic pressure fluctuations, which lead to a state change in the washing liquid without heat exchange, whereby local evaporation with subsequent blistering at the surface the parts to be cleaned can occur. This effect, referred to as cavitation, occurs particularly strongly on the solid surfaces of the parts to be cleaned, since the sound waves are reflected there and there is an increase in pressure. Since at the same time strong turbulences occur, not only the particles to be dissolved of the last processed with the rotary tablet press product are solved, but also by local currents, which arise in the vicinity of the interface between the liquid and the surface of the parts to be cleaned in the washing of removed from the surface.

The size and power of the ultrasonic transducer and possibly also the washing liquid may vary depending on the materials of the rotary tablet press and possibly with this product to be compressed, usually with a suitable ultrasonic transducer as ultrasonic transducer mechanical vibrations in the frequency range between about 20 kHz and 400 kHz can be generated, wherein for the ultrasonic cleaning depending on the particle size in particular frequencies in the range of about 25 kHz to 150 kHz, but also can be used to over 200 kHz for ultrasonic cleaning advantageous. In an advantageous embodiment, at least one ultrasonic transducer is arranged outside the working space. For this purpose, the ultrasound transducer can preferably be associated with a base pan with which the sealed working space in which the rotor is located in the production operation of tablets is bounded at the bottom. The arranged outside the working space ultrasonic transducer may in particular consist of a suitable vibrating element such as a plate oscillator. Additionally or alternatively, at least one or a further ultrasonic transducer can be arranged within the working space. The ultrasound transducer arranged within the working space can in particular be designed as an ultrasonic rod oscillator, as a submersible transducer or as a sonotrode.

In order to be able to generate ultrasonic waves for cleaning with the ultrasonic transducer or ultrasound transducers, at least one ultrasound generator connected to the ultrasound transducers is expediently provided for generating electrical oscillations, wherein a plurality of ultrasound frequencies for ultrasound cleaning can be set, particularly preferably with one ultrasound generator or possibly with several ultrasound generators . are producible. By using different ultrasonic frequencies particles of different particle sizes can be solved particularly well, since in general at very low frequencies between about 25 kHz to 40 kHz coarse dirt and at higher frequencies of 80 kHz to 120 kHz, for example, very fine soiling is particularly effectively solved. On the other hand, low-frequency ultrasound can attack the surface of the parts to be cleaned, so that possibly by switching the power of the ultrasonic generator to high-frequency areas with frequencies of about 60 kHz to 200 kHz, a gentler cleaning of the parts of the rotor and other parts of the rotary tablet press are effected in the working space can. The ultrasonic generator may also consist of a multi-frequency generator in order to achieve a coarse, fine and fine cleaning of the rotor during a washing cycle with different frequencies. Depending on the ultrasonic generator used, the ultrasonic transducers for a single frequency operation or Be designed multi-frequency operation. For this purpose, a special vibrating element can be provided in the ultrasonic transducer for each frequency or multifrequency ultrasonic vibrating elements are used.

In order to additionally increase the cleaning effect of the ultrasonic cleaning, a preferably controllable heating device and / or a cooling device for controlling or preferably regulating the temperature of the washing bath can be provided. Since most of the cleaning effect with ultrasound at higher temperatures of the wash bath is higher than at lower temperatures, therefore, the effectiveness of ultrasonic cleaning while reducing the downtime of the rotary tablet press can be further improved.

For the operation of a rotary tablet press with ultrasonic cleaning, it is necessary to exchange the parts to be cleaned in a washing bath. Consequently, this necessitates a working space which is at least largely sealed in a liquid-tight manner, since it must be prevented that the installation space in which the rotary tablet press is operated becomes contaminated with the washing liquid. At the same time, it is necessary, for example, to provide access to the working space for changing the dies, for repair work, for cleaning purposes or for other adjustment work. In order to achieve both, the working space preferably has at least one openable side wall which can be pressed or pulled against a housing-side seal by means of at least one closing means. By pressing or tightening the side wall against the seal, liquid leakage is prevented, provided that the side wall is closed. The side wall can hereby in particular also from a window or the like. consist. According to an advantageous embodiment, the seal is designed as a sealing channel with an inner sealing elements, an outer sealing element and a chamber located between them, wherein the chamber between the sealing elements can be acted upon with compressed air to increase the safety against liquid leakage. The pressurization of the chamber with compressed air can on the one hand prevent washing liquid from escaping at the seal in the case of slight leaks, since first the compressed air forces the washing liquid against the direction of flow. would urge, and also can be checked at any time by attaching, for example, sensors in the chamber, whether the sealing elements fulfill their sealing function optimally or substantially optimally. In the case of a pressure drop in the chamber, a maintenance interval can then be displayed automatically, for example, on a control unit for the rotary tablet press. As a closing means, at least one manually operable handle can be provided in order to allow good access to the working space at all times. According to an advantageous embodiment, at least one sensor for detecting the current position of the side wall and / or the position of the handle is present. Alternatively or preferably additionally, a further closing means may be designed as a motor-operated locking mechanism. The motor-locking mechanism can be coupled in particular to the previously described sensor and therefore only after closing the handle and reaching a first closed position of the side wall, the motor-locking mechanisms are operated. Possibly. It is sufficient to operate the motor locking mechanism only in the wash cycle, since only then the maximum seal is needed. This can extend the life of the seal used again, since their sealing function is required only in the washing mode.

Further preferably, at least one fill level sensor, in particular a sonar fill level sensor, may be provided for determining the fill level of the wash bath in the work space. The fill level sensor can preferably be connected to a higher-level control unit or the like. connected, in particular in dependence on the detection signal of the level sensor, to interrupt the supply of washing liquid and / or to control a drain of washing liquid, if e.g. the rotor is additionally rotated during a washing cycle with washing bath and ultrasound application, e.g. to improve the removal of the particles dissolved with ultrasound on the rotor. Alternatively or additionally, also stirring blades or the like. be arranged in the working space to produce additional movement or flow in the washing bath in the washing cycle at flooded working space.

In the case of rotary tablet presses with a washing device, there is always the danger that the washing liquid may also be introduced into the sliding guide. ments for the punches can penetrate, even if the upper and lower punches are usually assigned sealing elements. In order to avoid damage to the rotor even in the event of leaks in the sealing elements, in a particularly advantageous embodiment, a leakage channel for draining the washing liquid can be formed in the lower punch guide ring for each lower punch guide. The leakage channels should preferably only fulfill their discharge function if leaks occur unnoticed on individual sealing elements of the lower punch guides. Due to the inventively provided leakage channels even leaks of individual sealing elements could not lead to damage to the guides in Unterstempelführungsring and / or contamination of an oil or machine sump with washing liquid such as water in particular.

Further preferably, a sealing collar can be attached to the outer circumference of the lower die guide ring. In particular, the sealing collar can have a sealing lip which seals against the housing or a base trough of the rotary tablet press in the assembly or operating state of the rotor and forms a dynamic seal during the rotation of the rotor. It is particularly advantageous if the sealing collar and / or the sealing lip extend axially downwards beyond the mouth points of the leakage channels.

In order to improve the reliability of a rotary tablet press according to the invention with a washing device, a collecting line can moreover preferably be formed in the housing, via which the washing liquid derived from the leakage channels can be fed to a collecting container or to a drain. It is particularly advantageous if the manifold and / or the collecting container is associated with a sensor for detecting washing liquid inlet. With the corresponding sensor can thus be determined during the washing or cleaning phase within a very short time, if all sealing elements for the lower punch guides in the lower punch guide ring and / or have the dynamic seal seal gasket leaks. In addition, the washing phase may occur upon detection of wash liquid entry be switched off at short notice and automatically. A rotary tablet press with washing device and a sensor, the. Detects a Waschflüssigkeitseintritt in the leakage channels or the manifold, allows a highly reliable procedure when cleaning a rotary tablet press by the washing process is turned off if the washing liquid inlet is detected by the sensor. The provision of a single sensor is sufficient if the manifold is formed at the bottom of an annular channel, which is arranged below the lower punch guide ring and the dynamic seal in the housing. It is particularly favorable when the annular channel to the manifold is sloping down or is formed.

In a particularly preferred embodiment, a sealing ring seat for a preferably additional sealing ring is formed in the lower punch guide ring in each guide, opens at the level or above the associated leakage channel with its upper mouth opening into the associated guide. This additional sealing ring, for example, from an O-ring or the like. can exist and sealingly rests on the shaft of the lower punch, prevents any leaks occurring in the stamp guides associated sealing that a entering through a leaking sealing washer entering a greater depth in the guides and contaminate there befindliches lubricant or reduce its sliding effect. At the same time, the interaction of the additional sealing ring with the leakage channel ensures that the washing liquid does not accumulate above the sealing ring but is discharged via the leakage channel. Appropriately, for this purpose, the sealing ring seat is formed below a fastening means for the sealing member and / or the sealing member may in particular consist of a bellows seal. However, all interchangeable sealing elements can also. consist of seals with abutting the stamp shanks wiper lips.

For cleaning a rotary tablet press with washing device, a method is particularly advantageous which can be used as a method. Step comprises the filling of a liquid-tight in the housing of a rotary tablet press trained working space with washing liquid for exchanging a rotor in a washing bath comprises, according to the invention during at least a portion of a wash cycle, the washing bath is subjected to ultrasound.

When flooding of the working space in particular a procedure is advantageous in which the entire rotor including die plate, punch heads and sealing elements on the punches and possibly the working space facing the underside of Oberstempelführungsrings is washed by the washing bath. It is furthermore particularly advantageous if the rotor is set in rotation during the ultrasonic cleaning in order to generate a flushing flow in the washing bath, which flows around all parts of the rotor or working space which come into contact with the material to be pressed at a suitable flow rate , Further preferably, the washing bath can be heated before and / or during the ultrasonic cleaning by means of a separate heating device. Finally, the wash bath can be acted upon during a wash cycle with different frequencies.

Further advantages of a rotary tablet press according to the invention will become apparent from the subclaims and the following description of an embodiment shown schematically in the drawing. In the drawing show:

Fig. 1 schematically greatly simplified a rotary tablet press according to the invention with rotor, washing device and inventive ultrasonic cleaning, - and

Fig. 2 shows schematically a partial section of a rotary tablet press with Unterstempelführungsring and die plate in a sectional view.

In Fig. 1, a total of reference numeral 1 denotes a schematically greatly simplified illustrated rotary tablet press. The rotary tablet press 1 for producing, for example, medicament Medium tablets has a housing 2, a base construction 3, an upper cover 4 and a bottom trough 9, with which a working space 5, in which a rotor designated generally by 10 is arranged, is enclosed in a liquid-tight and / or dust-tight manner. The housing 2 has access to the working area at least one openable and closable door opening, through which the rotor 10 can be converted or optionally expanded. At the same time, a base trough 7 is supported with the base construction 3, on or on which, inter alia, a motor 8, not shown in detail, for driving the rotor 10 of the rotary tablet press 1 is arranged.

The rotor 10 comprises in known manner a lower punch guide ring 11 with numerous, preferably from guide holes sliding guides 12 for concentrically about the rotational axis D of the rotor 10 arranged and vertically movable lower punch 13, a Oberstempelführungsring 14 again consisting of holes sliding guides 15 for vertically movable and arranged concentrically about the axis of rotation D upper punch 16 and arranged between the Oberstempelführungsring 14 and the lower punch guide ring 11 die plate 17 arranged according to the number of upper punches 16 and lower punches 13 and aligned on these or their guides 13, 15 matrices 18. In The matrices can be made by compressing suitably supplied powder the desired tablets (not shown). In the embodiment shown, the upper punch guide ring 14, the lower punch guide ring 11 and the die plate 17 are designed as separate components. Individual or several of these individual elements could also be formed in one piece. The matrix disc or the matrices could also consist of several segments. In the exemplary embodiment shown, the individual elements of the rotor 10 are held together by means of a fastening screw 19, which is only indicated, and which is preferably arranged on the axis of rotation D.

For the vertical movement of guided with their shafts in the guides 12 lower punch 13 below the Unterstempelführungs- ring 11 a slide track 59 is formed, with which the head ends of the lower punch 13 slidably guided in a conventional manner and on and be moved off. The upper head ends of the upper punches 16 are moved in the embodiment shown by means of rollers 20 in the associated guides 15 and down to press the tablets in the matrices 18 during operation and eject at the end of the pressing operation up or down from the dies 18.

The rotary tablet press 1 is further provided with a washing device, of which only those projecting into the working space 5 washing nozzles 21 and 22 together with associated supply lines 23, 24 are shown in FIG. In the illustrated embodiment, the supply of a suitable washing liquid, in particular water to the nozzles 21 via the top cover 4 and to the nozzles 22 via the vertical struts of the housing 2 and the working space 5 is carried out sealed down by means of the trough 9 to in a Wash cycle to clean arranged in the working space 5 in the operational use and in operating position elements of the rotor 10 and the housing walls with the washing liquid to clean this with a pressure of eg 6 bar and a maximum throughput of, for example, 300 liters / min exits the nozzles 21, 22, while the rotor 10 rotates with the housing closed. The bellows seals 26 associated with the lower punch guides 12, which are fastened in the guides 12 or around the guides 12 in the lower punch guide ring 11, and the bellows 27 associated with the guides 15 of the upper punch 16 in the washing mode prevent the detergent liquid from entering the sliding guides 12 or 15 can occur. Bellows seals 26, 27 are associated with the punch guides 12 and 15 also in conventional rotary tablet presses, in order to prevent the normal operation of the rotor 10, when pressed with the upper and lower punches 16, 13 in the matrices 18 tablets, to prevent dust or powder in the sliding guides enters. An exchange of the bellows seals 26, 27 takes place either after predetermined maintenance intervals or visible damage to the sealing elements (bellows (26, 27)).

In Unterstempelführungsring 11 each guide 12 for the lower punch 13 is associated with a leakage channel 30 in the illustrated embodiment, as shown in the enlarged detail view of a partial section the rotary tablet press 1 in Fig. 2 can be seen. In FIG. 2, only a partial section of the lower die guide ring 11 and a partial section of the die plate 17 together with a section of the trough 9 are shown in section, wherein a circumference of the rotary tablet press 1 or of the lower die guide ring 11 and die plate 17 is distributed Variety of identical arrangements of punch guides 12, lower punches 13, dies 18 and leakage channels 30 and associated upper punch are arranged. Each leakage channel 30 extends obliquely, inclined in the illustrated embodiment by an angle of 45 ° relative to the central axis M of the guides 12 for the lower die 13, outwardly and opens into a circumferential groove 36 on the outer periphery 28 of the lower punch guide ring 11. The circumferential groove 36 is preferably formed around a constant cross-section and has a curved groove bottom 37, a likewise curved groove inner side 38 and an obliquely upwardly rising Nutoberflanke 39, which comprises the mouth point 31 of the leakage channel 30 in the circumferential groove 36. The upper end 32 of the leakage channel 30 opens substantially at the level of a sealing ring seat 29 for a sealing ring 40 at the bottom of a from the top 11 'of the lower punch guide ring 11th extending and concentric with the guide 12 executed blind hole (stepped step) of the guide bore 12 is disposed in the associated guide bore 12 for the lower punch 13. The sealing ring 40, the sealing surface of the shaft of the lower punch 13 rests sealingly, this sits below a Fixing ring 45 to which the Faltenbalgdich- lines 26 for the lower punch 13 and lower punch guides 12 are releasably aufklippbar.

The leakage channels 30 come only in the washing mode and only in operation when the associated bellows seal 26 has a leak in the bellows and / or the lower mounting ring 45. Only in this case, namely enters a small or larger amount of detergent liquid in the upper region of the blind hole of the guide 12 and can run in the blind hole up to the additional sealing ring 40. Because of above the Sealing ring 40 leaking leakage channel 30 is then, however, there enters the detergent liquid, supported by the rotational forces during rotation of the rotor 10 via the associated leakage channel 30 into the circumferential groove 36 which forms a drip nose due to the groove geometry, so that in the circumferential groove 36th accumulating amount of liquid down into a circumferentially formed below the lower punch guide ring 11 annular channel 50 is transferred. Preferably, at the lowest point of the annular channel, a manifold 51 connects to supply the discharged via the leakage channels 30 detergent liquid to a collecting container 52 shown schematically in Fig. 1.

As shown in Fig. 2, the manifold 51 may be associated with a sensor 55 for detecting any liquid entry into the manifold 51, e.g. to signal to the operator via the signal from the sensor 55 that a leak must be present on at least one bellows seal 26 for the lower punches 13. In case of greater liquid entry, the washing cycle can also be automatically interrupted immediately. Alternatively, as indicated in the exemplary embodiment in FIG. 1, a sensor 56 can also be assigned to the collecting container 52 in order to detect a liquid inlet into the collecting container 52 with it.

As can be seen particularly well in FIG. 2, the collecting line 51 is preferably arranged in alignment with and below the outer side 28 of the lower punch guide ring 11, the annular channel 50 extending as far as a vertical wall section 9A of the trough 9. At the same time a sealing sleeve 60 is circumferentially attached to the lower punch guide ring 11 above the circumferential groove 36, which extends down over the lower mouth point 31 of the leakage channel 30 and a sealing lip 61 which rests sealingly on the trough 9 during rotation of the rotor 10 as a dynamic seal in order to prevent liquid from entering the machine sump 7 or the motor 8 from the working space 5. Since the annular channel 50 as well as the collecting line 51 is located directly below the sealing point between the sealing lip 61 and the trough 9, a leak of these sealing elements can also occur with the sensors 55 and 56 at the same time. Cuff 60 are detected, so that the risk of leakage of this dynamic seal cuff 60 is minimized. The detection possibility for leaks of the dynamic seal is of independent inventive importance, even if, for example, no leakage channels would be present in the lower punch guide ring.

In order to improve the draining or draining of the washing liquid emerging from the leakage channels 30 in the event of leaks in the sealing elements 26 from the vertically aligned peripheral wall parallel to the axis of rotation, a concentrically encircling drip edge is provided at the transition of the peripheral wall 28 into the underside H '' of the lower die guide ring 11 34 formed, which preferably sharp-edged projecting about the bottom of a peripheral step 35 to Unterstempelfüh- ring. With the drip edge prevents liquid to the bottom II ' ^{1 of} the lower punch guide ring 11 can move and thus may possibly enter from below into the optionally lubricated with an oil film sliding guides 12 for the lower punch.

In the rotary tablet press 1 according to the invention, the working chamber 5 is formed sealed in such a liquid-tight manner that the working space 5 can be flooded to a desired level with washing liquid which enters via the nozzles 21, 22 and possibly further inflows, while the rotor 10 is in Operating position is located in the working space 5. The desired filling level during flooding of the working space 5 can be monitored with the level sensor 74 shown in FIG. 1, which is arranged here on the top wall 60 of the upper cover 4 and preferably consists of a sonar level sensor. With the level sensor 74 can be monitored in particular and regulated by means of a control unit, not shown for the rotary tablet press 1, that the level of the washing liquid in the working space 5 reaches a maximum of the bottom or an intermediate region of the upper punch guide ring 14. If the level of the washing bath, not shown, remains lower than the back of the upper punch guide ring 14, can on more expensive seals between the Oberstempelführungsring 14th and the receiving space for the rollers 20 to move the upper punch 16 are omitted. During flooding of the working space 5 in a washing cycle or cleaning cycle, which is carried out eg after completion of a production process, before changing elements of the rotor 10 or before converting the rotor 10 to another product to be pressed, in the rotary tablet press 1 according to the invention ultrasonically applied to the wash bath (not shown) resulting from the flooding to enhance the cleaning effect of the wash bath by the use of ultrasound. In order to introduce the ultrasonic waves, ultrasound transducers 70, 71 are arranged in the rotary tablet press 1, both inside and outside the working chamber. The arranged outside the working chamber 5 ultrasonic transducer 71 is fixed here on the underside of the bottom tray 9 and consists for example of a suitable vibrating element with, for example, sandwiched piezoelectric vibrating systems and a metallic vibrating plate to convert the ultrasonic frequency signal generated by the ultrasonic generator 73 in longitudinal waves, the be discharged into the wash. With the longitudinal waves are then by the cavitation effects, as known in ultrasonic cleaning, tablet dust, incrustations or other deposits on the surfaces of the submerged in the washing bath parts of the rotor 10 and the rotary tablet press 1 solved. In the exemplary embodiment shown, an ultrasound transducer 70 designed as a rod oscillator or sonotrode is additionally arranged within the working space 5 and is excited by the same ultrasound generator 73. In order to introduce sufficient power into the washing bath, a plurality of oscillating elements 71 or rod vibrators 70 could also be assigned to the working space 5 or oscillating elements 71 arranged exclusively outside the working space 5 or sonotrodes 70 arranged inside the working space 5 could be used. be provided. Either individual ones of the ultrasonic transducers 70, 71 could be designed for different frequencies, or the ultrasonic transducers 70, 71 are designed for multi-frequency operation to coarsely, finely and finely clean the parts of the rotor by changing the ultrasonic frequency from a low frequency to a higher frequency 10 to reach. For example, a multi-frequency ultrasonic transducer could be designed for the three frequencies 40 kHz, 80 kHz and 120 kHz to achieve a good cleaning result.

Thus, the working space 5 of the rotary tablet press 1 is liquid-tightly closed even if flooded or partially flooded working space 5 and at the same time remains accessible for retooling of the rotor 10, usually all four attached to the housing 2 side walls are designed as an apparent side wall 83, as with the one side wall 83 shown schematically. To open the side wall 83 by means of pivot joints (not shown), which are associated with the upper edge of the side wall 83, hinged to the housing 2 or to the upper cover 4. In order to achieve a liquid-tight closure of the working space 5 at the apparent side walls 83 at least during the washing cycle, the side wall 83 is tightened against a seal, which is arranged here substantially adapted to the edges of the side wall 83 and an outer, circumferential sealing element 78 and an inner circumferential sealing element 79, between which a chamber 82 is formed. The side wall 83 is closed during the closing operation first by means of a manually operable handle 77, which is preferably designed such that upon rotation of the handle 77, a sliding movement of the window wall 83 on the housing 2 and the seals 78, 79 is effected. The achievement of this first closed position of the side wall 83 can be monitored in particular with a sensor 76, which preferably opposite the lower edge of the side wall 83 and outputs a corresponding signal to a control unit (not shown) when reaching the manually effected closed position. Starting a wash cycle may be coupled by the control unit to whether the sensor 76 has signaled the closed position of the side wall 83 and whether motor locking mechanisms 75 have also been actuated which additionally apply the side wall 83 also near the upper edge of the side wall 83 against the seals 78, 79 tighten. For additional protection against leakage of liquid in the flooded working space 5, the start of the washing cycle can also be coupled thereto by first supplying compressed air via a compressed air line 80 and a compressed air valve 81 to the chamber 82 between the seals 78, 79. The chamber 82 can a sensor that detects a pressure drop in the chamber 82 to automatically detect leaks of the seals 78, 79.

In order to additionally increase the cleaning effect in the application of ultrasound to the washing bath, the washing liquid can be heated to a temperature advantageous for ultrasonic cleaning by means of a heating device, not shown, or if necessary also cooled during the application of the ultrasound to a certain temperature with a cooling device. In addition, it is advantageous if the rotor 10 is rotated during the cleaning cycle in order to improve both the dissolution of the dirt particles by means of ultrasound and the removal of the dissolved particles. For ultrasound application, instead of pure water, it would also be possible to use water or another washing liquid mixed with cleaning agent additives suitable for ultrasonic cleaning.

If leaks occur at the bellows 26 during the flooding of the working space, these could, as described above, be discharged by means of the leakage channels and automatically detected by the sensor 56.

Those skilled in the art will recognize from the foregoing description numerous modifications which are intended to be within the scope of the appended claims. It will be apparent to those skilled in the art that the number of workstations or press stations within the die plate and die guide rings does not matter. Due to the tight fit between the punches and the associated guides, the additional sealing ring can also be omitted. Also, the leakage channels do not have to be present. The sensors could also be positioned elsewhere. Instead of bellows seals, other sealing elements could be associated with the punches. To achieve optimum cleaning effect in a rotary tablet press, a wide variety of ultrasonic frequencies, ultrasonic transducers, ultrasonic vibration systems and ultrasonic generators can be used, and the output power of the ultrasonic generators and their frequency can preferably be determined digitally via the control unit. be adjustable unit of the rotary tablet press. Impellers could also be arranged in the working space to set the washing bath in motion during cleaning. The level of the washing bath in the working space can be varied during the washing cycle with ultrasound in order to achieve optimum reflection on the parts to be cleaned of the rotor or the working space.

Claims

Patent claim:

1. Rotary tablet press with a housing (2), with a in the housing (2) arranged drivable rotor (10), the pelführungsführung a (14) with guides (15) for upper punch (16), a lower punch guide ring (11) with guides (12) for lower punch (13) and between the punch guide rings (11, 14) arranged Matrizenscheibe (17), with a washing device (21, 22), with which the rotor (10) is washable by means of washing liquid, and with an im Housing formed, liquid-tight sealed working space (5), which can be filled with washing liquid for immersing the rotor in a washing bath, characterized in that the working space (5) at least one ultrasonic transducer (70, 71) for applying the washing bath is associated with ultrasound.

2. rotary tablet press according to claim 1, characterized in that at least one ultrasonic transducer (71) outside the working space (5) is arranged.

3. rotary tablet press according to claim 2, characterized in that the ultrasonic transducer (71) is associated with a bottom trough (9) with which the working space (5) is limited downwards.

4. rotary tablet press according to claim 2 or 3, characterized in that the ultrasonic transducer (71) is designed as a vibrating element, in particular as a plate oscillator.

5. rotary tablet press according to one of claims 1 to 4, characterized in that at least one ultrasonic transducer (70) is arranged within the working space.

6. rotary tablet press according to claim 5, characterized in that within the working space (5) arranged ultrasonic transducer is designed as an ultrasonic rod oscillator, immersion oscillator or Sonotrode.

7. rotary tablet press according to one of claims 1 to 6, characterized by at least one of the ultrasonic transducer (70, 71) connected to the ultrasonic generator (73) for generating electrical vibrations, wherein the ultrasonic generator generates frequencies of preferably between about 20 kHz to about 200 kHz and / or is designed as a multi-frequency generator.

8. rotary tablet press according to one of claims 1 to 7, characterized by a preferably controllable heating device and / or cooling device for controlling or regulating the temperature of the washing bath.

9. rotary tablet press according to one of claims 1 to 8, characterized by at least one level sensor (74), in particular a sonar level sensor, for determining the filling level of the washing bath in the working space (5).

10. rotary tablet press according to one of claims 1 to 9, characterized in that the working space (5) at least one openable side wall (83) by means of at least one closing means (77; 75) against a housing-side seal (78, 79) pressed or is appealing.

11. rotary tablet press according to claim 10, characterized in that the seal is formed as a sealing channel with an inner sealing member (79), an outer sealing member (78) and a chamber between them (82), wherein the chamber (82) between the sealing elements (78, 79) can be acted upon with compressed air.

12. rotary tablet press according to claim 10 or 11, characterized in that at least one closing means is designed as a manually operable handle (77).

13. rotary tablet press according to one of claim 10 to 12, characterized by a sensor (76) for detecting the current Position of the side wall, which is preferably arranged below the handle (77).

14. rotary tablet press according to one of claims 10 to 13, characterized in that at least one closing means is designed as a motor-locking mechanism (75).

15. Rotary tablet press according to one of claims 1 to 14, characterized in that the upper and lower punches (13, 16) sealing elements (26, 27) are assigned, wherein in the lower punch guide ring (11) for each lower punch guide (12) has a leakage channel (30) is designed for discharging the washing liquid in case of leaks in the sealing elements (26) of the lower punch guides (12).

16. rotary tablet press according to claim 15, characterized in that in the housing (2) a collecting line (51) is formed, via which the from the leakage channels (30) derived washing liquid to a collecting container (51) or outflow can be supplied, wherein the collecting line (51 ) and / or the collecting container (52) is associated with a sensor (55, 56) for detecting washing liquid inlet.

17. rotary tablet press according to claim 13 or 14, characterized in that the collecting line (51) at the bottom of an annular channel (50) is formed, the insurance ring below the Unterstempelfüh- (11) in the housing (2) is formed.

18 rotary tablet press according to one of claims 1 to 17, characterized in that on the outer circumference (28) of the lower punch - guide ring (11) a sealing collar (60) is fixed, which preferably has a sealing lip (61) in the assembled state of the rotor on Housing or a bottom trough (9) of the working space of the rotary tablet press sealingly.

19. A method for cleaning the rotor of a rotary tablet press, in particular according to one of claims 1 to 18, with the steps Filling a liquid-tight in the housing of a rotary tablet press trained working space with washing liquid for exchanging a rotor in a washing bath, characterized in that the washing bath is applied during a washing cycle with ultrasound.

20. The method according to claim 19, characterized in that the rotor is rotated during cleaning and / or the washing bath is set in motion.

21.A method according to claim 19 or 20, characterized in that the washing bath is heated before and / or during the ultrasonic cleaning with means of a separate heater.

22. The method of claim 19, 20 or 21, characterized in that the washing bath is acted upon during a washing cycle with different ultrasonic frequencies.