Method for producing individual doses by means of a roller-type dosing device
阅读说明:本技术 借助于辊式配给装置产生单个配给量的方法 (Method for producing individual doses by means of a roller-type dosing device ) 是由 S.布雷希特 B.汉德尔 M.希尔德 于 2019-08-08 设计创作,主要内容包括:本发明涉及一种用于借助于辊式配给装置(3)产生粉末状产品(1)的单个配给量(2)的方法。借助于测量装置依次确定多个排出的配给量(2)的单个质量。从中形成质量平均值并将该质量平均值与预设的内部额定质量范围进行比较。如果形成的质量平均值处于预设的内部额定质量范围之内,则在填充位置(I)中作用在配给开口(7)上的负压水平保持不变,并重新开始质量平均值的上述形成过程。如果形成的质量平均值处于预设的内部额定质量范围之外,则适配的负压如此获知:在质量平均值过低时提高负压水平,并且在质量平均值过高时降低负压水平,并且在填充位置中向配给开口(7)施加适配的负压。(The invention relates to a method for producing individual doses (2) of a powdered product (1) by means of a roller-type dosing device (3). The individual masses of the discharged doses (2) are determined in turn by means of a measuring device. From which a mass mean value is formed and compared with a preset internal nominal mass range. If the formed mass average lies within the predetermined internal target mass range, the vacuum level acting on the dispensing opening (7) in the filling position (I) remains constant and the above-described forming of the mass average is resumed. If the resulting mass mean value lies outside the predetermined internal target mass range, the adapted negative pressure is determined in such a way that: when the mass mean value is too low, the vacuum level is increased, and when the mass mean value is too high, the vacuum level is reduced, and in the filling position, a suitable vacuum is applied to the dispensing opening (7).)
1. Method for producing individual doses (2) of a powdered product (1) by means of a roller-type dosing device (3), wherein the roller-type dosing device (3) comprises a product reservoir (4), a dosing roller (5) and a measuring device (6) for determining the mass of the doses (2), wherein the dosing roller (5) is provided on a circumferential side with at least one dosing opening (7), wherein the dosing opening (7) is bounded on the inside by means of a filter element (8) and can be subjected to a negative pressure through the filter element (8), and wherein the method comprises the following steps:
-in a filling position (I), filling the dispensing opening (7) with a partial quantity of the powdered product (1) from the product storage (4);
-in the filling position (I), applying a negative pressure to the dispensing opening (7) through the filter element (8), wherein a dispensing quantity (2) of the powdered product (1) is formed in the dispensing opening (7);
-rotating the dosing roller (5) until the dosing opening (7) filled with the dosing quantity (2) is in a discharge position (III) in which the dosing quantity (2) is discharged from the dosing opening (7);
-continuing to rotate the dispensing roller (5) until the emptied dispensing opening (7) is again in the filling position (II);
-cyclically repeating the above steps several times, wherein the individual masses of a plurality of discharged rations (2) are determined in turn by means of the measuring device;
-forming a mass mean value from the determined individual masses of the plurality of discharged rations (2), comparing said mass mean value with a preset internal nominal mass range, and using for trend adjustment:
-if the formed mass average lies within the preset internal nominal mass range, the level of underpressure acting on the dispensing opening (7) in the filling position (I) remains unchanged and the above-mentioned forming of the mass average is resumed;
-if the resulting mass mean value lies outside the preset internal nominal mass range, the adapted negative pressure is known as such: the negative pressure level is increased when the mass average value is too low and is reduced when the mass average value is too high, and a suitable negative pressure is applied to the dispensing opening (7) in the filling position.
2. Method according to claim 1, characterized in that the formed mass mean value is also compared with a preset outer rated mass range, an adapted underpressure is then applied to the dispensing opening (7) in the filling position when the formed mass mean value is outside the inner rated mass range and within the outer rated mass range, and a fault signal is then generated when the formed mass mean value is outside the outer rated mass range.
3. Method according to claim 1, characterized in that a positive pressure is applied through the filter element (8) to the dispensing opening (7) in the discharge position (III) and the level of the positive pressure is adapted similarly to the negative pressure adapted to act in the filling position (I).
4. The method according to claim 1, characterized in that the pressure adaptation is carried out in a fixedly preset pressure step.
5. Method according to claim 1, characterized in that the pressure adaptation is carried out around an adaptation value which depends functionally on the degree of difference between the mass mean and the nominal mass.
6. Method according to claim 1, characterized in that the individual masses of a plurality of directly successively discharged doses (2) are determined in succession by means of the measuring device, and a mass mean value is determined from the individual masses of the determined, directly successively discharged doses (2).
7. Method according to claim 1, characterized in that in the case that the known level of adapted underpressure is outside an allowable pressure range, an actually adapted underpressure is applied to the dispensing opening (7) in the filling position, the level of which actually adapted underpressure corresponds to the respective limit value of the allowable pressure range.
8. The method according to claim 1, characterized in that the mass mean is formed by at least twenty determined individual masses.
9. Method according to claim 8, characterized in that the mass mean value is formed by at least one hundred determined individual masses.
10. Method according to claim 1, characterized in that the following method steps are additionally carried out:
-calculating a relative standard deviation thereof in addition to a mass mean value from the determined individual masses of the plurality of discharged rations (2) and comparing it with a preset limit deviation;
-if the calculated standard deviation is less than or equal to the limit deviation, the quality mean is used for the trend adjustment;
-generating a fault signal if the calculated standard deviation is greater than the limit deviation.
Technical Field
The invention relates to a method for producing individual doses of a powdered product by means of a roller-type dispensing device.
Background
For example, in the field of pharmaceuticals, but also in the field of dietary supplements and the like, powders are processed which have to be provided in precisely metered partial quantities or rations for a given dosage form. Target containers, for example in the form of blisters (blisters), plug capsules or the like, are filled with such metered doses of the powdered product, so that the appropriate unit dose is provided to the consumer and can be taken.
In particular, such powdered products are converted into single-measured doses in so-called roll dosing devices, which are then inserted into the respective target containers. Such roller-type dispensing devices comprise a dispensing roller which is provided on the circumferential side with at least one, usually a plurality of dispensing openings, wherein the dispensing openings are bounded on the inside by means of a filter element and through which a negative pressure can be applied. Under the effect of the underpressure, the powder is sucked into the dispensing opening, wherein a dispensing quantity of powder is formed, the volume of which corresponds to the volume of the respective dispensing opening. The resulting dose is then discharged from the dispensing opening and transferred to the target container.
As is clear from the above, the dispensing by means of the roller-type dispensing device is a volumetric dispensing. The aim is usually to provide a measured dose with a specific mass within the permitted tolerance. In practice, it has been found that the dosing quantity provided volumetrically by the roller-type dosing device does not always meet the requirements in terms of the quality of the actual realization.
Disclosure of Invention
The object of the present invention is therefore to provide a method by means of which individual masses produced by a roller-type dispensing device can be kept within predetermined tolerances in a simple manner.
This object is achieved by a method for producing individual doses of a powdered product by means of a roller-type dispensing device, wherein the roller-type dispensing device comprises a product reservoir, a dispensing roller and a measuring device for determining the mass of the doses, wherein the dispensing roller is provided on the circumferential side with at least one dispensing opening, wherein the dispensing opening is bounded on the inside by means of a filter element and can be acted upon by a negative pressure through the filter element, and wherein the method comprises the following steps:
in the filling position, the dispensing opening is filled with a partial amount of the powdered product from the product storage;
in the filling position, a negative pressure is applied through the filter element to the dispensing opening, wherein a metered amount of the powdered product is formed in the dispensing opening;
-rotating the dosing roller until the dosing opening filled with the dosed quantity is in a discharge position in which the dosed quantity is discharged from the dosing opening;
-continuing to rotate the dispensing roller until the emptied dispensing opening is again in the filling position;
-cyclically repeating the above steps several times, wherein the individual masses of a plurality of discharged rations are determined in turn by means of a measuring device;
-forming a mass mean value from the determined individual masses of the plurality of discharged doses, comparing the mass mean value with a preset internal nominal mass range, and using the following trend adjustment:
-if the formed mass average lies within a preset internal nominal mass range, the level of underpressure acting on the dispensing opening in the filling position remains unchanged and the above-described forming of the mass average is resumed;
if the resulting mass mean value lies outside a predetermined internal target mass range, the adapted negative pressure is determined in such a way that: if the mass mean value is too low, the vacuum level is increased and if the mass mean value is too high, the vacuum level is reduced and, in the filling position, a suitable vacuum is applied to the dispensing opening.
The invention is based firstly on the recognition that: the fluctuations to be observed in the actual dosing quality can be divided into two categories. In the first category, there is a short term fluctuation in which the individual quality is different from the subsequent or previous individual quality. In particular in the case of very small target masses of a few milligrams, such fluctuations between individual masses are due in particular to local density fluctuations in the powder, fluctuations in the degree of filling of the individual dosing openings and fluctuations in the degree of emptying when the dosing quantity is discharged. At this time, although it is possible to try to minimize the fluctuation within the first class as a whole, it is inevitable in principle.
The second category differs from this in that the quality changes occur over a longer period of time in a larger number of process cycles. According to the invention, it has been recognized that this is based on a gradual, trending change in the powder density in the metered dose, which in turn is mainly due to two influencing factors. On the one hand, the supplied powder may vary in its own properties. On the other hand, the filter element located at the bottom of the dispensing opening tends to become gradually clogged by the powder particles or the like during numerous process steps, which affects the level of negative pressure acting when sucking the powdered product. It has been observed that, with a constant pressure level maintained at the negative pressure source, the negative pressure actually acting in the dispensing opening is gradually reduced due to the gradually clogged filter element. As the applied negative pressure decreases, the density of the dose also gradually decreases, which leads to a gradual decrease in the mass of the dose, keeping the dose volume constant.
For this purpose, measuring devices for determining the quality of individual doses are now used within the scope of the invention. Preferred in this case are capacitance measuring systems, in particular with so-called AMV sensors (Advanced Mass verification sensor). However, other measuring systems or weighing systems may be used within the scope of the invention, which allow the determination of a single mass of a single dose or of a plurality of cumulative doses.
According to the present invention, it is now not the object to detect and influence the short-term quality fluctuations of the first kind mentioned above. But rather to the knowledge of trends, which is why individual masses of a plurality of dispensed portions are determined in succession by means of a measuring device, from which individual masses a mass mean value is then formed. For this purpose, it is sufficient to detect only every second, third or nth dose and to form an average therefrom. However, it is preferred that individual masses of a plurality of directly successively discharged doses are determined in succession, from which the mass mean is then determined. In any case, the resulting mass mean value is compared with a preset internal nominal mass range.
Depending on the result of this comparison, at least two different basic situations now occur. In the first case, the vacuum level acting on the dispensing opening in the filling position remains constant if the resulting mass mean value lies within a predetermined internal nominal mass range. I.e. no adaptation of the operating parameters is performed. But rather continues the current dosing process unchanged, wherein a new cycle of measuring and forming a mass average is started.
In the second case, however, the adapted negative pressure is determined if the resulting mass mean value lies outside the predetermined internal setpoint mass range: the negative pressure level is increased when the mass mean value is too low and the negative pressure level is decreased when the mass mean value is too high. Now in its filling position, an adapted underpressure is applied to the dispensing opening. The effect of the possibility of causing a change in the quality of the dispensed quantity while keeping the dispensed volume constant by varying the level of negative pressure is utilized here. The actual readjustment of the metering mass by the negative pressure adaptation described above is intended to bring the metering mass back within the predetermined internal target mass range. However, the regulation according to the invention is not a regulation of a single mass, but rather a regulation of the actually realized single mass with its mass mean value determined by a plurality of measurements, which corresponds to a trend regulation and is referred to herein as a trend regulation. Disturbances to the adaptation process caused by individual short-term outliers (ausreissers) or fluctuations of the first kind mentioned above are not taken into account, whereas long-term variations, for example due to product changes or filter element clogging, can be reliably accommodated. This adjustment can be fully automated comfortably and reliably without operator intervention. An increase in the operational life of the machine is achieved in a user-friendly manner. Efficiency is improved by avoiding mis-dosed product. Furthermore, the method according to the invention can be integrated into process monitoring. Deviations in process parameters and product fluctuations can be identified early, so that timely corrections can be achieved.
In addition, it is expedient to compare the resulting mass mean value with a predetermined external nominal mass range. If the resulting mass mean value lies outside the inner nominal mass range, an adapted underpressure is still applied to the dispensing opening in its filling position if this condition is additionally met within the outer nominal mass range. However, if the resulting mass mean value lies outside the outer nominal mass range, it is concluded therefrom that there is an excessively large and therefore problematic deviation. In which case a fault signal is generated. Depending on the fault signal, the process can be interrupted, for example, while the adaptation of the negative pressure is stopped.
In a suitable embodiment of the roller-type dispensing device, a positive pressure is applied to the dispensing opening in its discharge position through the filter element, in order to thereby blow or discharge the metered quantity out of the dispensing opening. In a preferred embodiment of the method according to the invention, the level of the positive pressure acting on the filling site is adapted in a similar manner to the negative pressure acting on the filling site. For this purpose, it is possible, for example, to take into account the fact that, for a reproducible quality determination, for example by means of a capacitance measuring system, this depends on repeated, constant discharge conditions. By adapting the positive pressure level as described above, the influence of the gradually clogged filter element can be compensated, so that the blow-out conditions can be kept constant in a desired manner.
In a first advantageous variant, the pressure adaptation is expediently carried out in a fixedly predefined pressure step. For this purpose, a low adjustment cost is required, which helps to simplify the process. In an alternative variant, the pressure adaptation takes place around an adaptation value which depends functionally (fully) on the degree of difference between the mass mean value and the target mass. In such a functional (e.g. proportional) adaptation, a very precise readjustment is possible. The described pressure adaptation variants can equally be used for negative pressure adaptation and/or also for positive pressure adaptation.
The possibilities of pressure adaptation inside the roller-type dispensing device are limited. In particular, only a limited range of available negative pressures can be provided. In the case of a known adapted underpressure level outside the permissible pressure range, an actually adapted underpressure is applied to the dispensing opening in the filling position, the level of which corresponds to the respective limit value of the permissible pressure range. Although this is not an exactly desired adaptation of the negative pressure. The less significant adaptation that accompanies this is sufficient for the mass average actually achieved thereby to remain within the permitted range, so that production can continue. Only when a mass average value no longer within the permissible range is detected is a fault signal generated, on the basis of which a production interruption can be carried out.
In order to reliably determine the mass mean value and to determine the trend of the mass change exhibited thereby, it is desirable to further eliminate the effect of unavoidable short-term mass fluctuations. This can already be achieved by deriving such a mass average from only a few individual masses. Preferably, however, the mass mean is formed from at least 20, in particular at least 100, individual masses determined. In particular, it is expedient to start with determining the mass average value with a smaller number of individual masses first, and then to use a larger number of individual masses to determine the mass average value as the process reliability develops.
In an advantageous embodiment of the invention, the following method steps are additionally carried out: in addition to the calculation of the mass mean value from the determined individual masses of the plurality of dispensed quantities, the relative standard deviation thereof is also calculated and compared with a preset limit deviation. If the calculated standard deviation is less than or equal to the limit deviation, the mass mean is used for trend adjustment. If the calculated standard deviation is greater than the limit deviation, a fault signal is generated. This ensures that the trend adjustment according to the invention is only used on the basis of sufficiently reliable measurement data.
Drawings
Embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the drawings:
fig. 1 shows a schematic cross-sectional view of a roller-type dispensing device having a product storage device, a dispensing roller and a measuring device for determining the mass of individual doses when carrying out the method according to the invention.
Detailed Description
Fig. 1 shows a schematic cross-sectional view of a roller-type dispensing device 3, which is in the production of individual doses 2 of a powdered product 1 and is used to transfer such individual doses 2 into a
The roller-type dispensing device 3 comprises a product storage device 4, a dispensing
The dispensing
The dispensing
The
In the filter strips 11, branched
The
The dispensing
If necessary, a negative pressure can be applied to the
The applied underpressure can also be kept at the same level or at a reduced level until the discharge position 43 is reached to prevent the dose 2 from prematurely falling out of the dispensing
In any case, when the dispensing opening is in the lower discharge position 43, the positive pressure adjusted in this way is transmitted through the
Part of the measuring device 6 already mentioned above for determining the mass of the individual doses 2 is a
In any case, in the
However, it may be the case that, in particular, subsequently, during a gradual, slow change in the conditions, a mass average value outside the preset internal setpoint mass range is determined. This may be due to varying product properties and/or slowly clogging
From this point on as well, the process of dosing and measuring continues, wherein a new cycle of determining the single mass and forming the mean value now begins. If this new mean value is now again within the internal nominal mass range already mentioned above, the previously adapted negative pressure is now held constant. Otherwise, a further adaptation is carried out according to the previously described mode until the known mass average is now within the preset internal setpoint mass range in a manner to be expected.
However, the adaptation or trend adjustment of the negative pressure described above has certain additional limitations. A preset outer rated mass range may be used as such an additional limit. The outer nominal mass range may, for example, correspond to a tolerance range within which the metered dose is still acceptable, and outside which the dose must be discarded. Alternatively or additionally, it can be determined by means of an external nominal mass range that the average mass value outside the nominal mass range is too far from the desired value and therefore the sought trend adjustment must be assumed not to lead to the desired result. In any case, it is an alternative according to the invention to also compare the formed mass mean value with the external nominal mass range. Only when the resulting mass mean value lies outside the inner nominal mass range and within the outer nominal mass range, the dispensing opening is subjected to an adapted underpressure in the filling position according to the above-described pattern. However, if the resulting mass mean value lies outside the outer nominal mass range, a fault signal is generated, which can be used, for example, to terminate the dosing process.
The additional comparisons described above should also be explained here by way of example. An exemplary external nominal mass range is determined to be 17mg to 23 mg. The average mass value already mentioned above, which is known as a value of 18mg, lies outside the exemplary internal nominal mass range of 19mg to 21mg, but within the exemplary external nominal mass range of 17mg to 23 mg. The adaptation of the negative pressure is thus performed as described above. However, when a mass mean value of, for example, 16mg is determined, this mass mean value lies outside the exemplary external nominal mass range of 17mg to 23mg, which leads to an error report. In this case, it is assumed that the trend adjustment limit is exceeded, i.e. the trend adjustment according to the invention may not lead to the desired result and a corresponding countermeasure has to be initiated.
Another limitation to be taken into account may for example be the limit of the available negative pressure. It may be the case that, by means of the trend adjustment according to the invention, a suitable vacuum is known, which is completely impossible to provide from the system side. If the level of the known adapted negative pressure is outside the allowed or available pressure range, this can be recognized and the process can be aborted. In this case, however, the process does not necessarily have to be aborted. Rather, it is expedient to apply a virtually adapted underpressure to the dispensing opening in the filling position, the level of which corresponds to the respective limit value of the permissible pressure range. If the above-mentioned trend regulation then for example results in that a relative underpressure of-800 mbar should first be applied and subsequently a relative underpressure of-900 mbar should be applied in the upper filling position 41, while a relative underpressure exceeding-850 mbar cannot actually be provided, so that this-850 mbar is now used as the corresponding limit value for the permissible pressure range.
As already mentioned above, in addition to the
Depending on the application, it is expedient to carry out the above-described pressure adaptation in a fixedly preset step, either at 100mbar or 50mbar, for example. Alternatively, the pressure adaptation is carried out with an adaptation value which depends functionally on the degree of difference between the mass mean value and the target mass.
Alternatively, the relative standard deviation of the mass mean is calculated in addition to the mass mean from the determined individual masses of the plurality of dispensed doses 2 and compared with a preset limit deviation. If the calculated standard deviation is less than or equal to the limit deviation, the measurement column is considered to be process technically correct and statistically usable. Therefore, the mass average is used for trend adjustment. However, if the calculated standard deviation is greater than the limit deviation, the measurement column is considered as being technologically unusable or statistically unusable. A fault signal is then generated, which is used by the borrower to take appropriate countermeasures. It is particularly expedient then to discard the resulting mass average, i.e. not to use it for further trend adaptation.
All of the above measures contribute to a reliable process trend regulation (trendelegelung) or trend regulation (trendezzregelung). However, this applies only to the course of trend adjustment and has no direct effect on the classification or good/bad separation of the individual portions 2. For the latter, the individual mass of the individual measurements of the individual doses 2 should be taken into account.
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