System for continuous processing of powdered products

Abstract

The invention relates to a system for continuously processing a powdery product, comprising a system inlet for the powdery product, a mixer for continuously mixing the powdery product, having a mixer inlet connected to the system inlet and a mixer outlet for a product mixture produced from the powdery product, a production machine for continuously processing the product mixture, having a machine inlet connected to the mixer outlet and a machine outlet for articles produced by the production machine, a conveying device being arranged between the mixer outlet and the machine inlet, a first fill level sensor being arranged on a filling device of the production machine for measuring a fill level of the powder therein, a second fill level sensor being arranged on a conveying reservoir of the conveying device between the mixer outlet and the conveying device for measuring a fill level of the powder therein, a control device being provided, which receives measurement data determined by the first and second fill level sensors and manipulates production parameters of the production machine on the basis of the measurement data.

Description

Technical Field

[0001] The present invention relates to a system for continuously processing powdered products, the system comprising at least two system inlets for the powdered products, a mixer for continuously mixing the powdered products, the mixer having at least one mixer inlet connected to the at least two system inlets, and the mixer having a mixer outlet for a product mixture made from the powdered products. Furthermore, the system includes a production machine, particularly a rotary press or capsule filling machine, for continuously processing the product mixture, the production machine having a machine inlet connected to the mixer outlet and a machine outlet for producing articles from the product mixture by the production machine, and a conveying device for conveying the product mixture from the mixer outlet to the machine inlet is provided between the mixer outlet and the machine inlet. Background Technology

[0002] In such systems, pharmaceutical products in oral solid dosage forms (OSDs), such as tablets and capsules, are processed. For this purpose, a rotary press or capsule filling machine is installed as a production machine. Different powdered products, such as at least one active pharmaceutical ingredient (API) and at least one excipient, are continuously supplied through multiple system inlets. These powdered products supplied through the system inlets are typically supplied in quantitative form to a mixer via a metering device, which manufactures a mixture of products to be processed in the production machine from the powdered products. The powdered products can be continuously supplied to one or more inlets of the mixer and mixed therein. The manufactured product mixture is provided at the outlet of the mixer for supply to the production machine. The product mixture supplied through the inlets of the production machine is processed into the corresponding product in the production machine, and the manufactured product is provided at the outlet of the production machine, where it is supplied to further processing, such as a packaging step.

[0003] Such a system is known, for example, from EP 3 013 571 A1. The components of this system, particularly the inlet, metering device, mixer, and tablet press, are arranged vertically stacked, so that the powdered product flows from the inlet and metering device to the mixer and tablet press due to gravity. A disadvantage of this arrangement is that the system requires a height of 5 meters or more. This necessitates a specialized production facility and complicates access for operators.

[0004] WO 2020 / 260600 A1 discloses a system for the continuous processing of powdered products, in which a supply module, a metering module, and a mixing module are arranged laterally next to a production machine, such as a rotary press. This side-by-side arrangement of system components on a common floor has the advantage of significantly reducing the system's height and enabling its use in ordinary production workshops. It also facilitates operator access. Due to this side-by-side arrangement, the mixer outlet is located at a lower level vertically than the production machine inlet. The product mixture supplied by the mixer must be correspondingly brought from the lower level to the higher level of the production machine inlet. For this purpose, WO 2020 / 260600 A1 preferably discloses a pneumatic vacuum conveying device. This vacuum conveying device effectively prevents undesirable separation of components in the product mixture.

[0005] For example, in a rotary press, powder material filled in a cavity is pressed into a compressed product, particularly tablets, by an upper and lower punch. The powder material is filled into the cavity by a filling device of the rotary press. This filling device typically includes a filling tube through which the powder material typically falls into the filling cavity by gravity, and then back into the cavity by gravity. It is desirable to monitor the filling height in the filling device, particularly in the filling tube, to ensure sufficient powder availability at all times. The same applies, for example, to capsule filling machines. It has been proposed to place sensors inside the filling tube for this purpose. However, placing sensors in the powder material flow causes interference with the powder flow, such as, for example, the formation of bridging structures. This can undesirably affect powder availability.

[0006] A rotary tablet press is known from DE 10 2017 207 162 A1, which has a capacitive fill height sensor for measuring the powder height in an ascending tube that leads into a filler shoe. EP 2 400275 A1 also describes a device for non-invasive, non-contact capacitive fill height measurement of bulk material in a container. The fill height sensor does not contact the filling medium whose fill height should be determined. Instead, electrodes are provided, arranged similarly to flip-up plate capacitors, and a high-frequency alternating electric field is generated between the electrodes, which non-destructively passes through the material to be measured. The capacitance of this capacitor depends on the dielectric constant of the filling material. Here, the filling material to be measured has a dielectric constant different from that of air. In this way, different degrees of coverage of the sensor surface by the material to be measured result in different capacitances of the capacitor. The fill height of the material in the container can thus be determined.

[0007] Here, external interfering factors, such as external electromagnetic fields or external objects, such as an operator's hand near the measuring electrodes, can cause problems. To reduce susceptibility to external influences, EP 2 400 275 A1 proposes setting multiple measuring electrodes in different horizontal planes, defining a measuring surface with vertical extension, and providing at least one reference electrode defining a reference surface with vertical extension. Each of the multiple measuring electrodes forms a capacitor with the reference electrode. Here, at least two capacitors are measured and the measured values ​​are correlated. Through a reliability check, the external influence of the interference source should be eliminated using calculations. However, such known devices are costly in terms of structure and evaluation techniques. Furthermore, such reliability checks do not always provide reliable results.

[0008] Furthermore, to provide protection against external interference sources in capacitive fill height measurement, a so-called active shielding is known in practice. In this active shielding, the electrodes used as shields are controlled to the same voltage potential as the measuring electrodes during measurement. While active shielding can reduce the impact of external interference sources, there is still a need for improved protection against interference in this type of capacitive fill height measurement.

[0009] In systems of the type described above, having a conveying device for transporting the product mixture supplied at the mixer outlet to the machine inlet of the production machine, the quantity of product supplied at the machine inlet by the conveying device may fluctuate. For example, the pneumatic vacuum conveying device described above circulates or intermittently transports the product mixture to the machine inlet. Here, a vacuum is first created at the outlet of the conveyor section, and a certain quantity of product is transported through the conveyor line under vacuum. Next, the outlet valve of the conveyor line is opened to supply the transported quantity of product to the machine inlet. The outlet valve is then closed, and this cycle is repeated. That is to say, in such a conveying device, fluctuations in the quantity of product supplied are inherent to the system.

[0010] It is known that, especially in systems of the type discussed here operating continuously for extended periods, errors accumulate in the mass flow of system components. These errors must be compensated for to achieve normal production operation, for example, by manipulating the appropriate product parameters of the production machine. This can be done, for example, based on a fill height sensor mounted on the filling device of the production machine. However, control or regulation based on fill height measurements taken at the filling device of the production machine can only be satisfactorily achieved when a substantially continuous product flow enters the filling device from the mixer. But in practice, and in relation to the conveying equipment used, this is precisely not the case. This fluctuation practically makes it impossible to maintain a constant fill height in the filling device, for example, by controlling or adjusting the production parameters of the production machine. Summary of the Invention

[0011] Based on the prior art, the object of the present invention is therefore to provide a system of the type described above, which overcomes the problems mentioned above. In particular, the object of the present invention is to achieve reliable control of at least one production parameter of the production machine when the quantity of product supplied at the machine inlet via the conveying device fluctuates.

[0012] The objective is achieved by the system according to the invention. Advantageous design solutions are shown in the specification and drawings.

[0013] For systems of the type described above, the present invention achieves the objective by providing a first filling height sensor on the filling device of the production machine for measuring the filling height of powder in the filling device, and a second filling height sensor on the conveying reservoir of the conveying device located between the mixer outlet and the conveying device for measuring the filling height of powder in the conveying reservoir, and providing a control device that receives measurement data determined by the first and second filling height sensors, and the control device is configured to operate at least one production parameter of the production machine based on the received measurement data.

[0014] The system according to the invention is used for the continuous processing of powdered products, particularly dried powdered products. As mentioned above, this relates, for example, to pharmaceutical products. Thus, the powdered product comprises, for example, at least one active pharmaceutical ingredient (API) and at least one excipient. The powdered product is supplied to the system via at least two, for example, more than two system inlets. Each system inlet may include a metering device for measuring the supply of product. The powdered product supplied via the system inlets is continuously supplied to the at least one mixer inlet via connecting pipes. The mixer continuously produces a product mixture from the supplied powdered product for further processing in a production machine. The product mixture is provided at the mixer outlet and continuously supplied to the machine inlet of the production machine via a conveying device. It should be noted that, in contrast to batch processing known per se, continuous supply specifically involves continuous processing. Continuous supply via conveying devices also includes intermittent supply, such as supply via, for example, pneumatic conveying devices. The production machine may be, for example, a rotary press, particularly a rotary tablet press, which compresses the supplied product mixture into compressed articles, particularly tablets, in a manner known per se. However, the production machine could also be, for example, a capsule filling machine, which fills the product mixture into capsules in a manner known per se. Articles, such as compressed articles, particularly tablets, or capsules, made from the product mixture by the production machine, are provided at the machine's outlet. Further processing, such as dust removal and / or packaging, can be performed.

[0015] The system is a continuously operating system, meaning that, unlike systems that operate on a batch principle, the system continuously mixes the supplied powdered product and processes it into articles, such as compressed articles, particularly tablets or capsules. The system can be hermetically sealed, for example having a hermetically sealed rating measured according to, for example, the OEB3 level as determined by the SMEPAC test (Standardized Test for Particulate Air Concentration in Equipment).

[0016] According to the present invention, a first filling height sensor for measuring the powder filling height in the filling device is provided on the filling device of the production machine. A second filling height sensor for measuring the powder filling height in the conveying reservoir is provided on the conveying reservoir located between the mixer outlet and the conveying device. The measurement data determined by the first and second filling height sensors are received by the control device of the system, and the control device operates at least one production parameter of the production machine based on the received measurement data from the two filling height sensors.

[0017] A filling device, equipped with a filling height sensor, supplies a product mixture to a production machine for processing, particularly for manufacturing into articles. Here, the filling device includes, in principle, all components positioned between the inlet of the production machine and the portion of the product mixture supplied for processing, such as the mold plate of a rotary press. The filling device may, in particular, include a vertically arranged filling pipe through which the product mixture is conveyed by gravity. The conveying reservoir of the conveying device, in its simplest form, consists of a tubular section positioned downstream of the mixer outlet, for example, connected to the mixer outlet. The conveying reservoir may also be constructed, for example, in the form of a funnel-shaped feed hopper, with its inlet connected to the mixer outlet and its outlet connected to the conveying pipe of the conveying device. Before the product mixture is conveyed to the production machine by the conveying device, the conveying reservoir forms a buffer for receiving and supplying the product mixture. The conveying device then conveys the product mixture from the conveying reservoir. The conveying device may include a conveying pipe, such as a conveying hose, through which the product mixture is conveyed.

[0018] This invention is based on the concept that, as explained above, the filling height measured in the filling device of a production machine may fluctuate due to the conveying of a product mixture via a conveying device. This makes it difficult, or practically impossible, to control the production parameters of the production machine based on a single filling height measurement downstream of the conveying device. Therefore, according to the invention, a second filling height sensor is provided upstream of the conveying device, which measures the filling height in the conveying reservoir. Based on the relationship between the two measured filling heights, conveying fluctuations that inevitably occur via the conveying device for various reasons can be identified and compensated for for control purposes. Thus, for example, overfilling the filling device with the product mixture via the conveying device for a short period of time causes a short-term increase in the measured filling height in the filling device and a corresponding short-term decrease in the filling height in the conveying reservoir. By examining the two filling heights together, this fluctuation in the conveying volume can be identified, and the production machine can be reliably controlled independently of this fluctuation. When using an intermittently operating pneumatic conveying device, the desired balance of the mass flow in the system can also be reliably ensured at all times, thereby theoretically ensuring the continuous operation of the system.

[0019] The first and second fill height sensors operate on the same measurement principle. The first and second fill height sensors can be technically identical in configuration. This improves the comparability of measurement results. The control device can also be, for example, a regulating device that adjusts the mass flow through the system by manipulating at least one production parameter of the production machine to a desired, particularly constant, value based on received measurement data.

[0020] According to one design, the mixer outlet can be positioned at a lower level than the machine inlet. In this design, for example, the supply, metering, and mixing module, including the system inlet, metering device (if necessary), and mixer, can be located next to the production machine, specifically on the same floor level as the production machine. As mentioned earlier, this arrangement advantageously achieves a low structural height, thereby ensuring usability in a conventional production workshop and good accessibility of system components to operators. However, this arrangement requires a conveying device to transport the product mixture provided at the mixer outlet from the lower level of the mixer outlet to the higher level of the machine inlet of the production machine.

[0021] According to another design, the conveying device can be a pneumatic conveying device that intermittently conveys the product mixture from the mixer outlet to the machine inlet. For example, the pneumatic conveying device can be a sealed-flow suction conveying device. This type of pneumatic conveying device is particularly suitable for conveying product mixtures because it minimizes the risk of undesirable separation of the components of the product mixture. Thus, for example, it can also reliably convey powdered products of different particle sizes in the form of corresponding product mixtures without undesirable separation. As previously described, for example in a pneumatic vacuum conveying device, a vacuum is first cyclically created at the outlet of the conveying pipe, such as a conveying hose or pipe, and a first quantity of product is conveyed through the conveying pipe by said vacuum. Next, the opening valve of the conveying pipe is opened to discharge the conveyed quantity of product toward the machine inlet. Then, the outlet valve is closed again and the cycle is restarted. That is, in such a pneumatic vacuum conveying device, fluctuations in the quantity of product supplied are inherent to the system because the product can be said to be packaged and thus intermittently conveyed from the mixer outlet to the machine inlet.

[0022] According to another design, the control device can be configured to manipulate at least one production parameter of the production machine based on received measurement data, such that the sum of the powder filling heights measured by the first and second filling height sensors is (as constant as possible). Specifically, this is achieved through adjustment by a control device, which can be an adjustment device at this point, until the sum of the powder filling heights measured by the filling height sensors is constant. This design utilizes the above understanding that an increase in the amount of product in the filling device of the production machine, especially when using an intermittently operating conveyor, causes a corresponding decrease in the amount of product in the conveyor's storage tank, and vice versa. That is, in a steady state of the system, the sum of the powder filling heights in the filling device and the conveyor storage tank is constant. If this sum changes, it means that an undesirable change has occurred in the mass flow through the system, such as the mixer conveying an excessive amount of product. In this case, the increase in the filling height in the conveyor storage tank is greater than the decrease in the filling height during filling. That is, the sum of the filling heights increases and can offset this change in mass flow. Therefore, the production parameters of the production machine can be controlled or adjusted based on the sum of the filling heights measured by the filling height sensors. To avoid erroneous measurement data and consequently incorrect control or regulation during the conveying cycle of, for example, a pneumatic conveying device, the control device can be configured to interrupt control during the conveying cycle. This conveying cycle is shorter than the stop time between cycles. This stop time is particularly suitable for control or regulation according to the invention. However, control or regulation can also be implemented without interruption, in which case it is based on the currently measured filling height. The amount of product conveyed during the conveying cycle can then be estimated by computer.

[0023] According to another design, the production machine can be configured as a rotary press, which includes a rotor rotatable by a rotary drive. The rotor has an upper punch guide structure for an upper punch and a lower punch guide structure for a lower punch, and a die plate disposed between the punch guide structures. The punches cooperate with the cavity of the die plate. In addition, the rotary press also includes a filling device and at least one pressure device. The filling device fills the cavity of the die plate with the powder material to be pressed, and a first filling height sensor is disposed on the filling device. The pressure device cooperates with the upper punch and the lower punch during operation to extrude the powder material in the cavity of the die plate. Furthermore, the rotary press also includes an ejection device, in which the pressed product formed in the cavity is ejected.

[0024] The rotary press can be, in particular, a rotary tablet press. In a rotary press, the product mixture to be processed is supplied to a die platen via a filling tube. The product mixture can be conveyed by gravity through a filling device and a filling tube. That is, the filling tube can be configured as a drop tube. The filling tube can be arranged to suit this purpose. For example, the longitudinal axis of the filling tube extends sufficiently obliquely relative to the horizontal direction, particularly, for example, vertically. Furthermore, the filling device has at least one filling cavity into which the product mixture enters from the filling tube. The product mixture is supplied from the filling cavity to the cavity of the die platen, particularly also by gravity, where the product mixture is pressed into a compressed article, particularly a tablet, by an upper and lower punch in a manner known per se. The cavity can be formed directly through a hole in the die platen. However, a detachably fixed die sleeve can also be provided in the die platen, in which the cavity is formed.

[0025] According to a particularly practical design, the control device can be configured to manipulate at least the rotational speed of the rotary press rotor based on received measurement data as production parameters. By manipulating the rotor speed, the mass flow through the system can be influenced in a simple and rapid manner. Thus, an increased rotor speed allows for the processing of more product mixtures per unit time.

[0026] The mixer preferably has a horizontally oriented mixing tube, in which a mixing device for continuously mixing powdered products is provided. The mixing device may, for example, include a spiral mixer, which is rotated by a rotary drive of the mixer.

[0027] The first and / or second fill height sensor may be capacitive fill height sensors. As already mentioned, such capacitive fill height sensors allow for accurate and non-contact measurement of fill height without interfering with powder flow.

[0028] According to another design, the filling device has a filling tube, on which a first measuring electrode of a first filling height sensor is disposed. The first measuring electrode and the first reference electrode of the first filling height sensor constitute a first capacitor, so that an electric field can be formed between the first measuring electrode and the second reference electrode. The first electrode is covered on its side facing away from the filling tube by a conductive shielding structure, which is at ground potential.

[0029] Accordingly, according to another design scheme, the second measuring electrode of the second filling height sensor is set on the conveying storage device. The second measuring electrode and the second reference electrode of the second filling height sensor form a second capacitor, thereby forming an electric field between the second measuring electrode and the second reference electrode. The second measuring electrode is covered by a conductive protective shielding structure on its side facing away from the conveying storage device. The protective shielding structure is at ground potential.

[0030] First and second measuring electrodes, respectively disposed on the filling tube or delivery reservoir, cooperate with a first or second reference electrode. The measuring and reference electrodes together form a capacitor, similar to a plate capacitor. The first or second measuring electrodes extend along the axial direction of the filling tube or delivery reservoir in defined measuring areas. The reference electrodes may also extend in these areas. An electric field formed between the measuring and reference electrodes passes through the interior of the filling tube or delivery reservoir and thus non-destructively through the powdered product to be measured. The capacitance of the correspondingly formed capacitor depends on the dielectric constant of the medium through which the electric field passes. Air, for example, has a different dielectric constant than the product mixture. Therefore, the degree to which the electrode is covered by the powdered product mixture can be determined by measuring the capacitance of the corresponding capacitor. This, in turn, determines the filling height. Multiple first measuring electrodes or multiple second measuring electrodes can also be provided. Similarly, the reference electrode may comprise multiple (sub) reference electrodes or be formed from multiple (sub) reference electrodes.

[0031] In the aforementioned design, the first or second measuring electrode is covered, in particular completely covered, on its side facing away from the filling tube or delivery reservoir by a conductive and grounded protective shielding structure. The filling tube or delivery reservoir can be made of, for example, metal, such as stainless steel. The protective shielding structure can also be made of metal, such as aluminum, or also stainless steel. Based on the understanding that the active shielding described above is insufficient for measuring the filling height of powdered products, especially in current applications, to obtain reliable measurement results despite potential external interference sources, the aforementioned design also relies on the understanding that conveying powdered products through the filling device or delivery reservoir can cause the product mixture to become statically charged, which can affect the measurement results. Due to the requirement for particularly high measurement accuracy, it is essential to reliably prevent external interference, such as interference from external electromagnetic fields or personnel near the filling height sensor. This is achieved through a conductive protective shielding structure placed at ground potential. This protective shielding structure reliably shields the measuring electrode against external electromagnetic interference sources. This allows for reliable determination of the filling height of the product mixture in the filling tube or delivery reservoir. Simultaneously, it avoids the complex setup of multiple measuring electrodes and eliminates the need for complex and unreliable reliability checks. The internal geometry of the filling tube or delivery reservoir remains undisturbed, and the powder flow is not affected or interfered with by the measuring sensors. Unlike existing technologies, instead of using a computer to eliminate external interferences, such as electrical equipment in a rotary press or interference caused by operator contact, these interferences are effectively suppressed beforehand.

[0032] According to another design, the first measuring electrode can be disposed in a non-conductive holding section on the filling tube, and / or the second measuring electrode can be disposed in a non-conductive holding section on the delivery reservoir. This achieves further improved shielding. For example, a non-conductive plastic, such as POM, can be used. The holding section can be integrally covered by the protective shielding structure. An outer peripheral bag can be provided in the holding section for the first or second measuring electrode, and, if necessary, for additional measuring electrodes.

[0033] According to another design, the retaining section can be disposed within a recess in the filling tube and / or the delivery reservoir. The filling tube or delivery reservoir then has a cutout in which the retaining section with a first or second measuring electrode is disposed. In this way, a particularly good measurement access port for the product mixture can be achieved, thereby enabling particularly accurate measurements without the risk of interfering with the powder flow.

[0034] According to another design, the conductive tube section before and / or after the filling tube equipped with the first measuring electrode can be at the same ground potential and / or the conductive tube section before and / or after the conveying reservoir equipped with the second measuring electrode can also be at the same ground potential. The inventors recognize that during the conveying of the product mixture through the filling device, particularly the filling tube or conveying reservoir, the powder material of the product mixture can become statically charged. According to the inventors, this is due to friction between the powder material and the powder-guiding components of the filling device or conveying reservoir. By grounding the conductive tube section upstream of the filling tube or conveying reservoir equipped with the first or second measuring electrode, this static electricity can be eliminated before capacitive filling height measurement, thus preventing distortion in subsequent measurements. During further powder material conveying after filling height measurement, undesirable static charge may further / reappear on the powder material. This static charge can adversely affect the processing results in the production machine. To prevent this, it may also be reasonable to ground the conductive tube section downstream of the filling tube equipped with the first measuring electrode or the conveying reservoir equipped with the second measuring electrode. The tubular section can be made of, for example, metal, such as stainless steel.

[0035] The first or second reference electrode can also be disposed on the filling tube or delivery reservoir where the first measuring electrode is located. The reference electrode can also be covered by a conductive protective shielding structure on its side facing away from the filling tube or delivery reservoir.

[0036] The filling tube equipped with the first measuring electrode and / or the delivery reservoir equipped with the second measuring electrode, especially their walls, can also be at ground potential. In this way, in addition to particularly reliable measurement and additional electromagnetic shielding, static charge on the powdered product mixture in the filling tube or delivery reservoir equipped with the first or second measuring electrode can be prevented or eliminated.

[0037] According to another design, the first reference electrode is formed by a filling tube with a first measuring electrode and / or the second reference electrode is formed by a delivery reservoir with a second measuring electrode, particularly its wall portion. In this way, the first or second measuring electrode directly forms a capacitor with the filling tube or delivery reservoir serving as the reference electrode. Therefore, compared to placing the first or second reference electrode on the filling tube or delivery reservoir, an expanded reference electrode can be used as the basis for capacitance measurement. Particularly accurate and reliable capacitance measurement can be achieved when the filling tube or delivery reservoir, and if necessary, a corresponding protective shielding structure, is also at ground potential.

[0038] According to another design, a third measuring electrode can be provided on the filling tube. This third measuring electrode, together with the first reference electrode, forms a third capacitor, thereby creating an electric field between them. The measuring range of the third measuring electrode is selected such that it is always completely covered by the product mixture in the filling tube during the operation of the rotary press. The extension dimension of the third measuring electrode along the longitudinal direction of the filling tube, and thus its measuring range, is smaller than the extension dimension of the first measuring electrode along the longitudinal direction of the filling tube, and thus smaller than its measuring range. For example, the extension dimension of the third measuring electrode may not exceed 15%, preferably not more than 10%, of the first measuring electrode. The third measuring electrode may, in particular, be parallel to the first measuring electrode and terminate substantially flush with or protrude from its lower end. By providing such a third measuring electrode, which is completely covered by the product mixture in the filling tube during the operation of the rotary press, filling height measurement is possible even for different powder materials or when the composition of the powder material changes. Therefore, when the third measuring electrode is completely covered by the powder material, it can be determined that the electric field formed between the third measuring electrode and the first reference electrode is entirely formed within the powder material. When the length of the third measuring electrode along the longitudinal direction of the filling tube is known, the filling height of the product mixture can be calculated from the capacitance measured against the first measuring electrode, even for different powder materials, without additional calibration. Thus, measurements can be performed independently of possible variations in the powder material or its composition. It has been shown that this method can further improve measurement accuracy.

[0039] According to another design, a fourth measuring electrode can be provided on the filling tube. This fourth measuring electrode and the first reference electrode constitute a fourth capacitor, thereby creating an electric field between them. The measuring range of the fourth measuring electrode is selected such that it remains above the filling height of the product mixture in the filling tube at all times during the operation of the rotary press. The extension dimension of the fourth measuring electrode along the longitudinal direction of the filling tube, and thus its measuring range, is smaller than the extension dimension of the first measuring electrode along the longitudinal direction of the filling tube, and thus smaller than its measuring range. For example, the extension dimension of the fourth measuring electrode may not exceed 15%, preferably not more than 10%, of the first measuring electrode. The fourth measuring electrode may end or protrude from the upper end of the first measuring electrode, particularly parallel to it and substantially flush with its upper end. By providing such a fourth measuring electrode, which is not, or may be partially, covered by the product mixture in the filling tube during the operation of the rotary press, measurements can be performed considering the possible characteristics of the filling device, particularly the filling tube, when the extension dimension of the fourth measuring electrode along the axial direction of the filling tube is known. In particular, it can identify changes in the measurement environment that occur during operation without affecting the product mixture, and take these changes into account when measuring the fill height via the first measuring electrode.

[0040] Correspondingly, a fifth measuring electrode can also be provided on the conveying reservoir. This fifth measuring electrode and the second reference electrode constitute a fifth capacitor, thereby creating an electric field between them. The measuring range of the fifth measuring electrode is selected such that it is completely covered by the product mixture in the conveying reservoir during system operation. Correspondingly, a sixth measuring electrode can also be provided on the conveying reservoir. This sixth measuring electrode and the second reference electrode constitute a sixth capacitor, thereby creating an electric field between them. The measuring range of the sixth measuring electrode is selected such that it is always above the filling height of the product mixture in the conveying reservoir during operation of the rotary press. This design of the conveying reservoir applies accordingly to the above description of the filling tube.

[0041] The third and / or fourth and / or fifth and / or sixth measuring electrodes may be covered by a conductive protective shielding structure on their side facing away from the filling tube and / or delivery reservoir. Attached Figure Description

[0042] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Wherein, schematically: Figure 1 The system according to the invention is shown in perspective view; Figure 2 A view showing the rotor unfolded is provided. Figure 1 The rotary press of the system shown in the figure; Figure 3 The test graph is shown in Figure 1 The first fill height sensor of the system shown in the figure; Figure 4 Show Figure 3 Sectional view along centerline AA; Figure 5 Shown in a partially sectional view Figure 1 A magnified view of part A in the image; and Figure 6 A diagram is shown to illustrate the control or regulation according to the present invention. Detailed Implementation

[0043] Unless otherwise stated, the same reference numerals in the figures denote the same content.

[0044] exist Figure 1 The diagram illustrates a system for the continuous processing of powdered products. The system includes a production machine 10, which in this case is a rotary tablet press 10. The rotary tablet press 10 is housed within a housing 12. A module housing 14 is disposed adjacent to the rotary tablet press 10 on the same ground surface. Figure 1 For the sake of display, the module housing 14 is shown with an open door 16. The housing 12 of the rotary tablet press 10 has a window 18, which can also be opened for access to the rotary tablet press 10.

[0045] The module housing 14 has three system inlets 20, 22, and 24 on its upper side, through which powdered products, such as active pharmaceutical ingredients and / or excipients, can be supplied. Each inlet 20, 22, and 24 has a metering device 26, 28, and 30, through which the supplied powdered product can be metered. Downstream of the inlets 20, 22, and 24 with metering devices 26, 28, and 30, in the illustrated embodiment, a supply funnel 32 is provided to guide the powdered product supplied through the inlets 20, 22, and 24 and the metering devices 26, 28, and 30 to the supply funnel. The outlet of the supply funnel 32 is connected to the mixer inlet 34 of a mixer 36. The mixer 36, in the illustrated embodiment, has a horizontal mixing tube 38 in which a mixing device, such as a rotatable spiral mixer, is disposed. The powdered product supplied via the supply funnel 32 is mixed into a product mixture in the mixing tube 38, and the product mixture is provided at the mixer outlet 40 of the mixer. The mixer outlet 40 is connected to a funnel-shaped conveying reservoir 42, which in the illustrated example is connected to the conveying device 44. The powdered product conveying device 44 further includes a conveying hose 46 connected to the outlet of the conveying reservoir 42, the other end of which is connected via an outlet feed hopper 48 to a machine inlet 50 on the upper side of the housing 12 of the rotary press 10. In the illustrated example, the conveying device 44 is a pneumatic vacuum conveying device 44. Accordingly, the conveying device 44 has a vacuum hose 52 and a vacuum generating unit 54. The vacuum generating unit 54 generates a vacuum at the outlet of the conveying hose 46 via the vacuum hose 52, through which the product mixture in the conveying reservoir 42 is conveyed through the conveying hose 46 to the outlet feed hopper 48 and then to the inlet 50 of the rotary press 10. For this purpose, the outlet valve at the outlet of the conveying hose 46 is opened intermittently and closed after the corresponding amount of conveyed product has been discharged. This cycle is then repeated, intermittently conveying the product mixture from the conveyor reservoir 42 from the mixer outlet 50, which is at a lower vertical level, to the machine inlet 50 of the rotary tablet press 10, which is at a higher vertical level. Tablets are then manufactured in the rotary tablet press 10 from the supplied product mixture in a manner that will be described in detail later. The tablets are output at the machine outlet 56 of the rotary tablet press 10, where they can be supplied for further processing, such as dust removal and / or packaging.

[0046] exist Figure 1The system shown is used to continuously process a powdered product into articles in a production machine 10, specifically into tablets compressed by a rotary tablet press 10 in the illustrated example. As mentioned above, the system can be closed. Of course, other production machines 10, such as capsule filling machines, can be installed in the system instead of the rotary tablet press 10. The structure and function of such a system described above are known in principle from WO 2020 / 260600 A1.

[0047] exist Figure 1 The system shown in the diagram differs from known systems, particularly in that a first filling height sensor 58, which will be described in detail below, is provided on the filling device of the rotary tablet press 10, and a second filling height sensor 60 is provided on the conveying reservoir 42 of the conveying device. Figure 1 The image is shown only very schematically, and references are provided below. Figure 5 The details will be further elaborated, and the difference lies in the analysis and evaluation of the measurement signals of the fill height sensors 58 and 60 according to the present invention.

[0048] exist Figure 2 An unfolded view of the rotor is shown, for example, in... Figure 1 The rotary tablet press 10 is applicable to the system shown in the figure. Figure 2The rotary tablet press shown includes a rotor driven to rotate by a rotary actuator (not shown in detail here), the rotor having a mold disk 62 with a plurality of cavities 64. The cavities 64 can be formed, for example, through holes in the mold disk 62. Furthermore, the rotor includes a plurality of upper punches guided in an upper punch guide structure 66 and a plurality of lower punches 72 guided in a lower punch guide structure 70, the upper and lower punches rotating synchronously with the mold disk 62. Each pair consisting of an upper punch 68 and a lower punch 72 is provided with a cavity 64. During the rotation of the rotor, the axial movement of the upper punches 68 and lower punches 72 is controlled by an upper control curve element 74 and a lower control curve element 76. The rotary tablet press also includes a filling device 78 having a filling cavity 80. The filling device 78 includes a funnel-shaped filling material reservoir 82 connected to the filling cavity 80 via a filling tube 84. In this manner, in the current example, the powdered product mixture enters the filling cavity 80 under gravity via the filling tube 84 and also enters the cavity 64 of the mold plate 62 by gravity via a filling port provided on the lower side of the filling cavity 80. Furthermore, the rotary tablet press includes a pressure device 86. The pressure device 86 has a pre-compression device with an upper pre-compression roller 88 and a lower pre-compression roller 90, and the main pressure device has an upper main pressure roller 92 and a lower main pressure roller 94. As the pressure device 86 passes through the cavity, the upper punch 68 and the lower punch 72 are pressed into the mold plate, and the product mixture filled into the cavity is compressed into tablets 100. Additionally, the rotary tablet press includes an ejector device 96, which in this case has a discharge member 98 that supplies tablets 100 manufactured in the rotary tablet press and conveyed to the upper side of the mold plate 62 by the lower punch 72 to the tablet outlet 102.

[0049] The control device 104 controls the operation of the rotary press and is primarily connected to the rotor's rotation drive via wiring not shown in detail. The control device 104 can also be an adjustment device 104, and the control device is also provided with measurement results from the first fill height sensor 58 and the second fill height sensor 60.

[0050] refer to Figure 3 and 4 First, let's describe in detail the first fill height sensor 58 that is installed on the fill tube 84. For example... Figure 4As shown, the filling tube 84 has a notch 106 in which a retaining section 108 made of a non-conductive material, such as plastic or POM, is disposed. The retaining section 108 carries a first measuring electrode 110 extending longitudinally along the filling tube 84, and third and fourth measuring electrodes 112 and 114 disposed parallel to the first measuring electrode 110, respectively. The third and fourth electrodes are parallel to the first measuring electrode and extend for approximately 10% of the length of the first measuring electrode. The third measuring electrode 112 is disposed in the region of the lower end of the first measuring electrode 110, while the fourth measuring electrode 114 is disposed in the region of the upper end of the first measuring electrode 110. Furthermore, the retaining section 108, along with the measuring electrodes 110, 112, and 114, is covered on its side facing away from the filling tube 84 by a non-conductive protective shielding structure 116, which is at ground potential. The filling tube 84 is also at ground potential in the illustrated example. The filling tube 84 and the protective shielding structure 116 may be made of, for example, metal. For example, the filling tube 28 is made of stainless steel, while the protective shielding structure 116 is made of aluminum.

[0051] The filling tube 84 is in Figure 3 and 4 In the embodiment shown, a first reference electrode is formed for measuring electrodes 110, 112, and 114. The measuring electrodes 110, 112, and 114 thus form three capacitors with the filling tube 84 serving as the first reference electrode, thereby creating electric fields between the measuring electrodes 110, 112, and 114 and the first reference electrode 84, respectively. During operation of the rotary press, the third electrode 112 is always completely covered by the product mixture located in the filling tube 84, while the fourth electrode 114 can be located above the filling height of the product mixture in the filling tube 84. The first measuring electrode 110, with its longitudinal extension dimension, constitutes a measuring range for measuring the powder filling height in the filling tube 84. During operation, electric fields are formed between the measuring electrodes 110, 112, and 114 and the filling tube 84 serving as the reference electrode, respectively, by means of a control device 104, and the capacitance of the correspondingly formed capacitors is also measured by the control device 104. The control device 104 determines the powder filling height in the filling tube 84 from the capacitance. The protective shielding structure 116, positioned at ground potential, effectively minimizes the influence of external interference. By using the filled tube 84, also positioned at ground potential, as a reference electrode, exceptionally accurate and reliable capacitance measurements can be achieved. The third and fourth electrodes 112 and 114 eliminate the influence of variations in the powder material or the characteristics of the filled tube 84 on the measurement results.

[0052] according to Figure 5 In Figure 1 A partial view of part A should be shown. Figure 1The second fill height sensor 60 is shown only schematically. Figure 5 In the partially cutaway diagram, a spiral mixer 118, which is disposed in the mixing tube 38 and can be rotated by the rotary driver 117, can be seen. It should be noted here that... Figure 5 In the middle, for display reasons, in Figure 1 Several components in the circled area A are not shown.

[0053] In the illustrated example, the second fill height sensor 60 has a second measuring electrode 120, which forms part of the wall 132 of the funnel-shaped delivery reservoir 42 in the region of the notch. The wall 132 of the delivery reservoir 42 also forms a second reference electrode in the illustrated example. The wall 132 of the delivery reservoir 42 may also be made of metal, such as stainless steel, and may preferably be at ground potential. The second measuring electrode 120 thus forms a capacitor with the wall 132 of the delivery reservoir 42 constituting the second reference electrode, thereby creating electric fields between the second measuring electrode 120 and the second reference electrode 132, respectively. The second measuring electrode 120 is also covered on its side facing away from the delivery reservoir 42 by a protective shielding structure 122 at ground potential. The protective shielding structure 122 may be made of metal, such as aluminum.

[0054] During operation, and under the control of the control device 104, an electric field is formed between the second measuring electrode 120 and the wall 132 of the delivery reservoir 42, which serves as the second reference electrode, and the capacitance of the formed capacitor is also measured by the control device 104. The control device 104 determines the powder filling height in the delivery reservoir 42 by measuring this capacitance. Similar to the first filling height sensor 58, the second filling height sensor 60 is also protected by a protective shielding structure 122 to minimize the influence of external interference. As already described with respect to the first filling height sensor 58, the second filling height sensor 60 corresponds to the third and fourth measuring electrodes 112, 114 described above for the first filling height sensor 58, and of course, the fifth and sixth measuring electrodes can also be arranged in a similar manner. In the example shown, the second measuring electrode 120 is further held by a holding section 124, which is made of, for example, plastic or POM, as in Figure 5 As shown in the diagram.

[0055] refer to Figure 6An evaluation of the measurement signals provided by the two fill height sensors 58 and 60 according to the invention should be described. Here, the fill height is shown in time in arbitrary units. The curve labeled 126 shows the fill height measured by the first fill height sensor 58 in the fill tube 84 of the filling device 78 of the rotary tablet press 10, while the curve labeled 128 shows the fill height measured by the second fill height sensor 60 in the delivery reservoir 42 of the delivery device 44. Another curve is shown at reference numeral 130, which corresponds to the sum of fill heights 126 and 128.

[0056] First, it can be seen that the fill height curves 126 and 128 are... Figure 6 In the idealized diagram, the opposite is formed. The shorter and steeper rises and falls of the curves correspond to the intake or delivery cycles of the pneumatic vacuum delivery device 44, respectively. In the longer sections in between, the filling height 126 in the filling tube 84 of the rotary tablet press 10 decreases, while the filling height in the delivery reservoir 42 increases. These sections correspond to the time intervals between the intake cycles of the delivery device 44, during which the powder mixture supplied to the rotary tablet press 10 is processed, while the delivery reservoir 42 is refilled by the mixer 36. In the system according to the invention... Figure 6 In the idealized steady state shown, the sum of the two fill heights is constant, as can be seen in curve 130. This is the desired steady state in which the mass flow through the system is constant.

[0057] In the system according to the invention, the control device 104 sums the filling heights measured by the first and second filling height sensors 58 and 60, i.e., curves 126 and 128, to obtain curve 130. If the control device 104 confirms that the sum increases or decreases, i.e., curve 130 increases or decreases over time, this indicates a change in the mass flow through the system. To eliminate this change in mass flow, the control device 104 manipulates a production parameter of the production machine 10 based on this, which, in the example shown, is the rotor speed of the rotary tablet press 10. Increasing the rotor speed correspondingly results in faster processing of the product mixture supplied to the rotary tablet press 10, while a lower rotor speed results in slower processing of the product mixture. In this way, the control device 104 can influence the mass flow through the system. As already described, the control device 104 may in particular be an adjustment device 104 that adjusts the measured filling height to a constant sum, i.e. a constant mass flow, by controlling the rotor speed of the rotary tablet press 10 based on the filling height measured by the first and second filling height sensors 58, 60.

[0058] List of reference numerals

[0059] 10 Production Machines / Rotary Tableting Machine

[0060] 12. Shell

[0061] 14 Module Housing

[0062] 16 doors

[0063] 18 windows

[0064] 20 System Entry

[0065] 22 System Entry

[0066] 24 System Entry

[0067] 26 Metering devices

[0068] 28 Metering devices

[0069] 30 Metering devices

[0070] 32 Supply Funnel

[0071] 34 Mixer Inlet

[0072] 36 Mixers

[0073] 38 Mixing tube

[0074] 40 Mixer outlet

[0075] 42 Conveying Storage

[0076] 44 Conveying device

[0077] 46. ​​Delivery hose

[0078] 48 Outlet feed hopper

[0079] 50 Machine entrances

[0080] 52 Vacuum hose

[0081] 54 Vacuum Generation Unit

[0082] 56. Machinery exports

[0083] 58 First Fill Height Sensor

[0084] 60 Second Fill Height Sensor

[0085] 62 Mold Plate

[0086] 64-type cavity

[0087] 66 Upper punch guide structure

[0088] 68 Upper punch

[0089] 70 Lower punch guide structure

[0090] 72 Downward Punch

[0091] 74 Upper control curve element

[0092] 76 Lower control curve element

[0093] 78 Filling device

[0094] 80 Filling cavity

[0095] 82 Filler Material Storage Container

[0096] 84 Filler tube

[0097] 86 Pressure Device

[0098] 88 Upper preload roller

[0099] 90 Lower preload roller

[0100] 92 Upper main pressure roller

[0101] 94 Lower main pressure roller

[0102] 96 Ejection Device

[0103] 98 Unloading parts

[0104] 100 tablets

[0105] 102 Tablet Exports

[0106] 104 Control Device

[0107] 106 Notch

[0108] 108 Maintaining Section

[0109] 110 First measuring electrode

[0110] 112 Third measuring electrode

[0111] 114 Fourth measuring electrode

[0112] 116 Protective shielding structure

[0113] 117 Rotary Driver

[0114] 118 Spiral Mixer

[0115] 120 Second measuring electrode

[0116] 122 Protective shielding structure

[0117] 124 Maintaining Section

[0118] 126 curves

[0119] 128 curve

[0120] 130 curve

[0121] 132 Wall of the conveyor storage container

Claims

1. A system for continuously processing powdered products, the system comprising at least two system inlets for the powdered products, a mixer (36) for continuously mixing the powdered products, the mixer (36) having at least one mixer inlet (34) connected to the at least two system inlets, and the mixer (36) having a mixer outlet (40) for a product mixture made from the powdered products, further comprising a production machine (10) for continuously processing the product mixture, the production machine (10) having a machine inlet (50) connected to the mixer outlet (40) and a machine outlet (56) for producing articles from the product mixture by the production machine (10), and a conveying device (44) for conveying the product mixture from the mixer outlet (40) to the machine inlet (50) provided between the mixer outlet (40) and the machine inlet (50), characterized in that, A first filling height sensor (58) for measuring the filling height of powder in the filling device (78) is provided on the filling device (78) of the production machine (10), and a second filling height sensor (60) for measuring the filling height of powder in the conveying reservoir (42) is provided on the conveying reservoir (44) between the mixer outlet (40) and the conveying device (44), and a control device (104) is provided, which receives measurement data determined by the first filling height sensor (58) and the second filling height sensor (60), and the control device is configured to manipulate at least one production parameter of the production machine (10) based on the received measurement data, such that the sum of the powder filling heights measured by the first filling height sensor (58) and the second filling height sensor (60) is as constant as possible.

2. The system according to claim 1, characterized in that, The mixer outlet (40) is positioned at a lower level than the machine inlet (50).

3. The system according to claim 1, characterized in that, The conveying device (44) is a pneumatic conveying device that intermittently conveys the product mixture from the mixer outlet (40) toward the machine inlet (50).

4. The system according to claim 3, characterized in that, The pneumatic conveying device is a sealed flow suction conveying device.

5. The system according to any one of claims 1 to 4, characterized in that, The production machine (10) is a rotary press, which includes a rotor that can be rotated by a rotary drive. The rotor has an upper punch guide structure (66) for an upper punch (68) and a lower punch guide structure (70) for a lower punch (72), and a die plate (62) disposed between the upper punch guide structure (66) and the lower punch guide structure (70). The upper punch (68) and the lower punch (72) cooperate with the cavity (64) of the die plate (62). In addition, the rotary press also includes a filling... The rotary press includes a filling device (78) and at least one pressure device (86) for filling the powder material to be pressed into the cavity (64) of the mold platen (62) via the filling device, and the first filling height sensor (58) is disposed on the filling device. The pressure device works in conjunction with the upper punch (68) and the lower punch (72) during operation to squeeze the powder material in the cavity (64) of the mold platen (62). In addition, the rotary press also includes an ejector device (96) in which the pressed product made in the cavity (64) is ejected.

6. The system according to claim 5, characterized in that, The control device (104) is configured to manipulate at least the rotor speed of the rotary press as a production parameter based on the received measurement data.

7. The system according to any one of claims 1 to 4, characterized in that, The mixer (36) has a mixing tube (38) in which a mixing device (118) for continuously mixing the powdered product is provided.

8. The system according to claim 7, characterized in that, The mixing tube (38) is horizontally oriented.

9. The system according to any one of claims 1 to 4, characterized in that, The first fill height sensor (58) and / or the second fill height sensor (60) are capacitive fill height sensors.

10. The system according to claim 9, characterized in that, The filling device (78) has a filling tube (84) on which a first measuring electrode (110) of a first filling height sensor (58) is disposed. The first measuring electrode and the first reference electrode of the first filling height sensor (58) constitute a first capacitor, thereby forming an electric field between the first measuring electrode (110) and the first reference electrode. The first measuring electrode (110) is covered on its side facing away from the filling tube (84) by a conductive protective shielding structure, which is at ground potential.

11. The system according to claim 10, characterized in that, A second measuring electrode (120) of a second filling height sensor (60) is provided on the delivery storage (42). The second measuring electrode and the second reference electrode of the second filling height sensor (60) constitute a second capacitor, thereby forming an electric field between the second measuring electrode (120) and the second reference electrode. The second measuring electrode (120) is covered on its side facing away from the delivery storage (42) by a conductive protective shielding structure, which is at ground potential.

12. The system according to any one of claims 11, characterized in that, The first measuring electrode (110) is disposed in a non-conductive holding section on the filling tube (84), and / or the second measuring electrode (120) is disposed in a non-conductive holding section on the delivery reservoir (42).

13. The system according to claim 12, characterized in that, The retaining section is disposed in the notch (106) of the filling tube (84) and / or the delivery reservoir (42).

14. The system according to claim 11, characterized in that, The conductive tube sections located before and / or after the filling tube (84) with the first measuring electrode (110) are also at ground potential and / or the conductive tube sections located before and / or after the delivery reservoir (42) with the second measuring electrode (120) are also at ground potential.

15. The system according to claim 11, characterized in that, The filling tube (84) with the first measuring electrode (110) and / or the delivery storage (42) with the second measuring electrode (120) are both at ground potential.

16. The system according to claim 11, characterized in that, The first reference electrode is formed by a filling tube (84) having a first measuring electrode (110) and / or the second reference electrode is formed by a delivery reservoir (42) having a second measuring electrode (120).

17. The system according to any one of claims 1 to 4, characterized in that, The production machine (10) is a rotary press or a capsule filling machine.

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