Device and method for multiple filling of highly viscous materials

Abstract

Device for filling a particularly highly viscous material into filling containers, comprising: (i) a first component comprising a material container with at least one dispensing nozzle; and (ii) a second component comprising at least one support for receiving the filling containers, wherein the support is arranged to be movable relative to the first component; characterized by (iii) Means for exerting a defined counterforce to the movement of the carrier caused by the dynamic pressure of the material during filling, wherein the means for exerting a counterforce comprises at least a control for controlling the counterforce as a function of at least one parameter.

Description

TECHNICAL FIELD

[0001] The application relates to a device and a method for filling a particularly highly viscous material into filling containers. The device comprises a first component comprising a material container with at least one dispensing nozzle; and a second component comprising at least one carrier for receiving the filling containers. STATE OF THE ART

[0002] Filling is a special form of batch-based formulation dosing with only a single component. Filling processes always occur in batches, i.e., in cycles or with multiple cycles. In filling technology, the actual dosing process takes a back seat.

[0003] Compared to dosing in product production, filling is unique in that certain tolerances must be maintained for the quantitative definition of the filling mass. Furthermore, legal regulations, particularly the Weights and Measures Act and the associated Weights and Measures Ordinance, stipulate compliance with tolerances. These tolerances are impossible or only possible with considerable effort, especially when filling highly viscous materials such as fillers used in dental technology. OBJECT OF THE INVENTION

[0004] It is therefore an object of the invention to provide a device and a method which allow even highly viscous materials to be filled with high accuracy with regard to quantitative specifications (filling quantities). TECHNICAL SOLUTION

[0005] The above-mentioned object is achieved by a device according to claim 1 and a method according to claim 7. Advantageous embodiments and further developments emerge from the features of the dependent claims.

[0006] A device according to the invention for filling a particularly highly viscous material into filling containers comprises: a first component comprising a material container with at least one dispensing nozzle; a second component comprising at least one carrier for receiving the filling containers, wherein the carrier is arranged to be movable relative to the first component by the dynamic pressure generated by the material during filling; and means for exerting a defined counterforce to the movement of the carrier caused by the dynamic pressure.

[0007] The dosing device essentially consists of a first component and a second component which has a carrier which is arranged to be movable relative to the first component.

[0008] The first component comprises a dosing cylinder (material container) with side walls and a piston base. The dosing cylinder contains the material to be filled (e.g., a composite for use in dental technology, dental materials). Flow nozzles (outflow or filling nozzles) are located in the cylinder base to allow the material to be filled to flow out of the cylinder. A piston or plunger presses the material in the dosing cylinder out of the flow nozzles by exerting force toward the outflow or filling nozzles.

[0009] The second component comprises a pallet and / or a workpiece carrier. A carrier (tray, table) is arranged on the workpiece carrier, which is movable relative to the workpiece carrier and is intended to accommodate, in particular, several filling containers (e.g., capsules). The receiving locations for the capsules are provided next to one another on the carrier, in one or possibly in several rows, adjacent to one another. The carrier can be connected to the pallet or workpiece carrier, for example, via preferably two or more linear guides, so that it can move relative to the pallet or workpiece carrier.

[0010] The dynamic pressure generated when the material flows from the flow nozzles in the filling containers and is transferred to the carrier creates a force that moves the carrier away from the nozzles toward the pallet or workpiece carrier. The second component has means that exert a counterforce against this force, which, however, is smaller than the force exerted by the dynamic pressure, so that the carrier with the filling containers is moved away from the nozzles during the filling process, guided by the linear guide(s).

[0011] The pallet or workpiece carrier can, for example, be connected to a movable NC axis via an NC lifting table. The movement of the NC axis can generate a relative movement of the pallet or workpiece carrier with respect to the first component. In this way, a movement can be generated that overlays the movement of the carrier with respect to the pallet or workpiece carrier and is also transferred to the carrier. In this way, greater fill heights can also be achieved, i.e. capsules with a greater height can be filled if the maximum distance that the carrier can be moved with respect to the pallet or workpiece carrier is less than the fill height or the height of the capsules. For longer filling strokes, the NC axis can therefore take over part of the path. The process itself does not become significantly more complex.

[0012] For example, depending on the design, the maximum pneumatically controlled travel s may be sufficient for filling smaller capsules. When filling larger capsules or syringes, a longer filling travel is required. This travel can be the sum of the travel x of the NC axis and the travel s of the proportional pneumatics. If, for example, the proportional pneumatics reaches a limit, the NC axis retracts by the amount Δx. The counterforce of the proportional pneumatics is freely adjustable depending on the travel.

[0013] The fill height corresponds to the entire travel of the carrier or the filling container and / or the second component. During the filling process, the carrier moves away from the first component under the dynamic pressure. It is "slowed down" by the counterforce. The speed of the carrier's movement is determined by the dynamic pressure (which depends on the flow behavior of the material) and the counterforce.

[0014] The device preferably comprises two or more dispensing nozzles. In the dental sector, for example, large quantities of highly viscous materials are filled into capsules. The average filling weight is usually between 200 mg and 350 mg. For the economical filling of large quantities, multiple filling is advantageous. Dispensing takes place in parallel through several nozzles into several filling containers. This is therefore a multiple filling process that is repeated in a series of consecutive cycles as soon as a batch of filling containers has been filled. After the filling process, the carrier can be loaded with new (empty) filling containers or replaced with a carrier with unfilled filling containers. For the new filling process (cycle), the carrier is moved back to a starting position near the dispensing nozzle(s). For dosing or filling, it is irrelevant how many capsules are filled at the same time.

[0015] In particular, the means for exerting a counterforce comprise at least one controller for controlling the counterforce as a function of at least one parameter. The parameter is determined, recorded, or measured during the filling process.

[0016] Preferably, the means comprise a device for measuring the distance traveled by the carrier from the beginning of the filling cycle, i.e., from the starting position. The maximum distance (filling distance) of the filling container(s) or the carrier relative to the first component is predetermined. Thus, the filling volume (distance times the cross-sectional area of ​​the filling container) is predetermined and remains constant for all filling cycles.

[0017] The counterforce can be exerted, for example, by a spring that counteracts the direction of movement of the second component. However, this has the disadvantage that the counterforce cannot be varied during the filling process. Therefore, the means can preferably be designed to generate a counterforce that is variable over the filling path. For example, proportional pneumatics can be provided to adjust the counterforce. This allows the counterforce to be varied during the filling process, e.g., depending on the path. However, the variable counterforce can be generated by any other suitable means. The counterforce can be controlled / regulated so that the counterforce is always generated according to a path-dependent function.

[0018] The device can have a control system that regulates the discharge pressure in the material container depending on the filling time of the filling containers. This means that between two filling cycles, if the filling time does not correspond to a target value or is not within a target range, the discharge pressure in the material container is changed to return the filling time to the target value or within the target range. However, other system parameters that influence the flow behavior of the material can also be controlled to implement the control. For example, the temperature of the material in the material container and / or in the nozzles can be changed.

[0019] In a further embodiment, the counterforce or the characteristics of the counterforce can be controlled during filling.

[0020] A method according to the invention for filling a particularly highly viscous material into filling containers comprises the steps: a) applying a discharge pressure to discharge the material from a material container into filling containers; b) Moving the filling containers due to the back pressure generated by the material flowing into the filling containers.

[0021] The filling containers or the carrier in which the filling containers are arranged adjacent to each other moves away from the nozzles under the influence of the back pressure.

[0022] In step b), in particular, a defined counterforce is exerted against the movement of the filling containers, which is caused by the back pressure when filling the filling containers.

[0023] The invention enables air-free descent against a controlled and regulated back pressure. The back pressure can vary during the filling process. The retention forces and travels are generated, for example, by electronically controlled / regulated proportional pneumatics ("air springs") with force / travel control.

[0024] One or more filling containers can be provided. The material can preferably be discharged in parallel through several discharge nozzles. Multiple fillings with high throughput take place in a number of consecutive filling cycles, with full filling containers being replaced with empty ones between each filling cycle.

[0025] In step b), the counterforce can be controlled or regulated depending on a measuring parameter.

[0026] In step b), the counterforce is controlled or regulated, particularly depending on the distance traveled by the filling containers during the filling process. The distance-dependent control / regulation ensures that filling is adapted to the flow behavior of the material.

[0027] In particular, the maximum distance traveled by the filling containers during the filling process is specified. The specified distance corresponds to the required weight. This determines the filling volume so that the filling containers can be filled with high accuracy, even in multiple filling operations (i.e., parallel filling). This allows strict specifications regarding filling accuracy to be met. Prior art processes used processes without volume determination. This makes the machines very simple and inexpensive to construct. However, the quality of the filling process is highly dependent on the skill and experience of the operators. Even slight fluctuations in flow rates can rapidly degrade the filling quality. The consequences are underdosing with air pockets or overdosing and contamination of the capsules. In addition to significant material losses and delays in production, the errors are visible to every user and disruptive to operation.With the present invention, however, automation of the filling process is possible. The invention is a true volumetric dosing method, i.e., a method in which the volume is determined by measuring the displacement.

[0028] Preferably, the speed of the filling containers during the filling process is determined by the dynamic pressure and the applied counterforce. Unlike conventional methods, the speed of the filling containers adapts to the flow behavior of the material during the filling process.

[0029] In particular, the filling time is also determined by the back pressure and the counterforce exerted during a filling process.

[0030] At the beginning of the filling process, the counterforce is briefly increased to force the material to be filled into the capsule opening, which is located at the bottom of the capsule (i.e., the area that is filled first). This "closes" the opening for the remainder of the filling process. The filling phase then proceeds with a lower counterforce.

[0031] At the end of the filling process (end of cycle), a viscoplastic break must occur because thread formation causes contamination. Therefore, within the scope of the invention, it is expedient to briefly increase the counterforce before the break. The control system can be configured so that the force increase occurs at a specific point along the filling path. The composite is then pressed firmly against the capsule wall up to the height of the dispensing nozzle. The material has strong adhesion in the nozzle and capsule. Due to the rapid force reduction and the carrier's removal, the material does not have sufficient time to constrict and breaks off. Horizontal viscoplastic fracture surfaces form in the capsule and nozzle.

[0032] With this setup, different filling processes can be generated.

[0033] In a particularly preferred embodiment of the invention, the discharge pressure is controlled as a function of the filling time of the filling containers between different filling cycles. This means that if the outflow behavior of the material from the nozzles drifts and thus changes the discharge characteristics, an adjustment can be made. The drift or change is reflected in a change in the discharge time measured for filling the filling containers. By adjusting parameters individually or in combination, e.g., the discharge pressure acting on the material in the material container, the filling process can be automated to achieve a satisfactory level of accuracy in the filling quantity.

[0034] The problems that arise with conventional methods due to the changing (usually accelerated) flow behavior of the material over time and after several cycles are eliminated with the present invention, as the filling paths are measured. If a critical (usually minimum) filling time is reached after a certain number of filling cycles, other parameters are adjusted so that the critical dosing time is not exceeded or undershot, i.e., a minimum dosing time is not undershot, for example. This control can be performed independently of an operator using appropriate machine software. The control parameters and relationships are stored in a matrix in the program.

[0035] The controls and / or regulations are implemented using appropriate software. This software can also be self-learning or self-optimizing.

[0036] The system is generally suitable for common automation systems such as rotary indexing machines, flexible assembly systems, or combinations thereof. Flexible assembly systems with pallet systems are preferred. Machine retooling can be achieved by changing pallets. The pallets can be calibrated outside of the automation system. The geometric and physical data are transferred to the transponders on the pallets. This allows each pallet to be tracked throughout the process. This data is read out at the dosing station. The corresponding filling parameters are assigned to the pallet from a matrix. Each product has its own specific dosing recipe, and correction data can be assigned to each pallet.

[0037] After the dosing process, a control measurement of the fill level in each capsule is performed. This data is assigned to the corresponding pallet. If individual capsules are not filled correctly, they are rejected at the end of the process. If errors occur regularly and are assigned to a pallet, the pallet is removed from production and replaced with a new one. If general errors occur, production is stopped, as the parameter set is obviously unsuitable for the dosing / batch. A review and reassessment are performed before damage occurs.

[0038] All of the features mentioned and effects described can be combined, regardless of whether they were explained in connection with the device or the method. SHORT DESCRIPTION OF THE CHARACTERS

[0039] Further features and advantages of the invention will become clear from the following description of preferred embodiments with reference to the figures. They show: Fig. 1 a sectional view of the device according to the invention; Fig. 2 a sectional view of a first section of the device according to the invention; Fig. 3 a sectional view of a second section of the device according to the invention; and Fig. 4 a sectional view of a device for explaining the outflow behavior. DETAILED DESCRIPTION OF THE FIGURES

[0040] The Fig. Figure 1 shows a filling device 1 according to the invention. The filling device 1 comprises a first component 2 and a second component 3.

[0041] The first component 2 comprises a dosing cylinder 20 with a side wall 201 and a base part 202. In addition, the first component 2 comprises a piston 21, which is acted upon by a force F, indicated by an arrow, via a press ram 22 in order to generate a discharge or dosing pressure in the material (composite) 4 arranged in the container.

[0042] The second component 3 comprises a pallet or workpiece carrier 30 and a receiving carrier 31. The receiving carrier 31 is movably connected to the workpiece carrier 30, as indicated by the double arrow v.

[0043] The workpiece carrier 30 is connected to an NC axis 33 via an NC lifting table 32. The NC axis 33 is arranged so as to be vertically movable relative to the first component 2, as indicated by the double arrow V. By moving the NC axis 33, a relative movement of the tool carrier 30 relative to the first component 2 can be generated. In this way, the movements of the NC axis and the holder carrier 31 relative to the workpiece carrier 30 can be superimposed. The movement of the NC axis 33 is also transferred to the holder carrier 31. In this way, greater fill heights can be achieved, i.e. capsules with a greater fill height can be filled. If the maximum path of movement v of the holder carrier 31 relative to the workpiece carrier 30 is not sufficient, it can be increased by moving the NC axis.

[0044] In the Fig. 2 is an excerpt from the Fig. 1, in which the NC axis and the area around the press ram have been omitted. Identical components are designated by the same reference numerals throughout.

[0045] Flow nozzles 23 are formed in the base part 202 of the first component 2. Composite 4 can be filled into capsules 5 via these nozzles, wherein the capsules 5 are arranged adjacent to one another in corresponding receiving locations of the receiving carrier 31.

[0046] The second component 3 also has linear guides 34 that extend from the workpiece carrier 30 in the direction of the first component 2. The receiving carrier 31 is connected to the workpiece carrier 30 via the linear guides 34 so that it can move vertically (movement v). The movement v of the receiving carrier 31 relative to the flow nozzles 23 is determined, on the one hand, by the back pressure exerted by the flowing composite 4 on the receiving carrier 31, and, on the other hand, by a counterforce G against the back pressure. The counterforce G is generated by a proportional pneumatic system 35 ("air spring") of the second component 3. The proportional pneumatic system 35 is connected to the workpiece carrier 30 and arranged between the workpiece carrier 30 and the receiving carrier 31.

[0047] In addition, the second component 3 has a measuring device 36, which is symbolically represented by a sensor 360 and a measuring scale 361. The measuring device 36 measures the distance traveled by the receiving carrier 31, starting from a starting position assumed at the beginning of the filling process. According to the invention, the proportional pneumatics 35 is controlled such that, depending on the distance determined by the measuring device 36, a defined counterforce G is exerted against the movement of the receiving carrier 31 generated by the dynamic pressure. The maximum distance traveled by the receiving carrier 31 from its starting position to the end position in which the capsules 5 are filled is predefined. The filling volume is thus also fixed. The (instantaneous) speed v of the receiving carrier 31 is determined by the dynamic pressure and the counterforce 35 exerted by the proportional pneumatics. The back pressure, in turn, depends on the flow behavior of Composite 4.

[0048] The Fig. Figure 3 shows further details of the device according to the invention. In the container area above the flow nozzles 23, the force Fine dosing pressure p d generated. In the two filling nozzles 230 and 231 shown as examples, different pressures p1 and p2 prevail. These pressures generate a dynamic pressure in the capsules 5, which pushes the receiving carrier 31 downwards, symbolized by the arrow v. The counterforce G generated by the proportional pneumatics 35 with force / displacement control depends on the filling distance or the distance traveled by the receiving carrier 31 from the starting position. The counterforce can be variably adjusted via the filling distance. During filling, it is always smaller than the force exerted by the dynamic pressure. This is calculated for the two nozzles shown as follows: F stau=p1*A+p2*A. Thus, the proportional pneumatics 35 are designed in such a way that during the filling process, they only allow the receiving carrier 31 to move downwards, but can exert different counterforces G depending on the distance traveled.

[0049] As in the Fig. 4 is shown, the material 4 to be filled is expelled from the container 20 through several nozzles 23 with constant pressure p d pressed out by exerting a force F on the piston 21. The material 4 flows out of the nozzles 23 at different speeds due to locally different flow properties. In this way, a tolerance band is created with regard to the filling accuracy with respect to a target value.

[0050] In the prior art, a time was specified during filling during which the material flows into the capsules. During this time, the nozzles are continuously withdrawn from the capsules. The available volume and the flow rate of the material must always be kept in balance. The back pressure should be large enough to prevent air pockets from forming and small enough to prevent overdosing. Because the flow behavior of many materials being filled into containers changes significantly over time, it is difficult to correctly determine calibration cycles, adhere to minimum fill weights, start up processes, rectify faults, etc. If deviations occur, readjustment is carried out by trained and experienced personnel.

[0051] The present invention, in contrast, works by determining the volume (corresponding to the displacement measurement multiplied by the filling cross-section). By building up a defined counterforce, the negative effects of variable flow rates are automatically compensated. If the filling time of consecutive filling cycles changes beyond a tolerance, system parameters are adjusted to adjust the filling time in the opposite direction. The process is therefore fully capable of automation.

[0052] Although the present invention has been described in detail with reference to the accompanying embodiments, it will be understood by those skilled in the art that the invention is not limited to these embodiments, but rather encompasses modifications or variations in accordance with the appended claims. These variations may be achieved by combining individual features shown or by omitting individual features. In particular, any combination of the features shown is encompassed by the invention.

Claims

[1] Device for filling a particularly highly viscous material into filling containers, comprising: (i) a first component comprising a material container with at least one discharge nozzle; and (ii) a second component comprising at least one carrier for receiving the filling containers, wherein the carrier is arranged to be movable relative to the first component; characterized by (iii) means for exerting a defined counterforce to the movement of the carrier caused by the dynamic pressure of the material during filling, wherein the means for exerting a counterforce comprises at least one control for controlling the counterforce as a function of at least one parameter. [2] Device according to claim 1, characterized by that the device comprises two or more application nozzles. [3] Device according to one of the preceding claims, characterized bythat the means comprise a device for measuring the distance travelled by the carrier from the start of the filling cycle. [4] Device according to one of the preceding claims, characterized by that the means have proportional pneumatics for adjusting the counterforce. [5] Device according to one of the preceding claims, characterized by that the device has a control which regulates the discharge pressure in the material container as a function of the filling time of the filling containers. [6] Method for filling a particularly highly viscous material into filling containers, comprising the steps: a) applying a discharge pressure to discharge the material from a material container into filling containers, and b) Moving the filling containers due to the back pressure generated by the material flowing into the filling containers, characterized bythat a defined counterforce is exerted against the movement of the filling containers, which is caused by the back pressure when filling the filling containers, and that the counterforce is controlled or regulated as a function of a measuring parameter. [7] Method according to claim 6, characterized by that the material is applied in parallel through several application nozzles. [8] Method according to one of claims 6 or 7, characterized by , the counterforce in step b) is controlled or regulated depending on the distance covered by the filling containers during the filling process. [9] Method according to one of claims 6 to 8, characterized by that the (maximum) distance covered by the filling containers during the filling process is specified. [10] Method according to one of claims 6 to 9, characterized by that the speed of the filling containers during the filling process is determined by the back pressure and the counterforce exerted. [11] Method according to one of claims 6 to 10, characterized by that the application pressure is regulated depending on the application time when filling the filling containers between different filling cycles.

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