Patent Publication Number: US-2022214207-A1

Title: Method for dosing a target component

Description:
BACKGROUND 
     The present invention concerns a method for dosing a target component. DE 102006054604 A1 discloses a packing machine for packing fine-grained product in packages, comprising a product feed unit, a dosing device, a receiving vessel and scales. 
     SUMMARY 
     A control device is provided which is connected to the scales and the dosing device in order to regulate the dosed quantity depending on the weight determined by the scales. It is an object of the present invention to further improve the accuracy, in particular when dosing a plurality of components. 
     In comparison, the method according to the invention for dosing a target component has the advantage that a more precise dosing of a component in a mixture can be performed automatically. In particular, over-dosing of an individual component in a mixture can be prevented. In the production of mixtures, quite often the individual components are weighed and indeed lie within the given tolerances, but do not correspond to the respective nominal weight. The method according to the invention can prevent a resulting ratio of components from deviating from the nominal value. Thus in many cases, the resulting total mass is not as important as the ratio of the individual components to one another, so that according to the invention, a correction is made in favor of a precise ratio. There is no need to reject a component already weighed, since all components are adapted in relation to the component to be precisely dosed. In particular with poorly flowing components which must be dosed precisely (for example, medicinal agents), use can be made of the fact that the components for after-dosing (auxiliary substances) usually offer a greater degree of freedom with respect to flowability or dosing accuracy. According to the invention, this is achieved in that the target component is dosed to a target value which corresponds to the desired nominal value, wherein firstly a further component for after-dosing is dosed to a target value which is lower than a desired nominal value of the component for after-dosing. Then a content of the target component is calculated depending on the actual value of the target component and/or the actual value of the component for after-dosing. The content is compared to the limit value or a tolerance band, wherein if the limit value or tolerance band is exceeded, at least the component for after-dosing is dosed again. Particularly preferably, the content is an absolute value, in particular the determined actual value of the target component, or a relative value, in particular the determined actual value in relation to a sum of the determined actual value of the target component and the determined actual value of the component for after-dosing. 
     In a suitable refinement, firstly yet a further component for after-dosing is dosed to a target value of the further component for after-dosing, wherein the target value of the further component for after-dosing is lower than a desired nominal value of the further component for after-dosing. Thus the flexibility is increased by dosing a plurality of components accordingly. Particularly preferably, if the content deviates from the limit value or tolerance band, the further component for after-dosing is also after-dosed again. 
     In a suitable refinement, if the content deviates from the limit value or tolerance band, the target component is also dosed again. This increases the flexibility of being able to intervene in the necessary fashion if the dosing is not yet satisfactory, without having to reject the dosing performed. 
     In a suitable refinement, if the content deviates from the limit value or tolerance band, the target value of the component for after-dosing is determined again. Preferably, the target value is determined again depending on the nominal value and/or actual value of the target component, particularly preferably depending on a factor of the quotient of the nominal value and actual value of the target component, and in particular multiplied by an actual value of the component for after-dosing. Thus the after-dosing can also be carried out if the target component is under-dosed. In this way, particularly easily, the correction can be made in favor of a precise ratio. 
     Further suitable refinements arise from the further dependent claims and the description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With reference to the appended figures, embodiments of the invention are now described in detail. The drawings show: 
         FIG. 1  a schematic overview of a possible apparatus for performing the method for dosing a target component, and 
         FIG. 2  a flow diagram of the method according to the invention for dosing a target component. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the figures, the exemplary embodiments of the invention are described in detail below. 
       FIG. 1  shows an apparatus  8  for dosing a target component  20 . The apparatus  8  comprises at least one dosing system  10  and a further dosing system  12  which dose different components, in particular a target component  20  and at least one further component  21 ,  22 ,  23  for after-dosing, into a mixture  25  in a recipient container  13  or mixer. The dosing systems  10 ,  12  are for example screw dosers, preferably gravimetric twin-screw dosers. Other dosing systems  10 ,  12  may also be provided, depending on application. The recipient container  13  may also comprise a mixing function so that the dosed components  20 ,  21  can also be mixed at the same time. 
     A controller  14  actuates the dosing system  10 . A controller  14  loads target values Z 20 , Z 21 , Z 22 , Z 23  into the respective dosing systems  10 ,  12 . The target values Z 20 , Z 21 , Z 22 . Z 23  serve as nominal values for the next dosing process in the respective dosing systems  10 ,  12 . The target value Z 20  of the target component  20  corresponds to the desired nominal value S 20   soll of the target component  20 . The target values Z 21 , Z 22 , Z 23  of the component  21  for after-dosing or components  21 ,  22 ,  23  for after-dosing however are selected lower than the desired nominal values S 21   soll , S 22   soll , S 23   soll of the respective component  21 ,  22 ,  23  for after-dosing. 
     After the dosing process, the controller  14  receives the true value or actual value G 20   ist of the target component  20 , and the actual value(s) G 21   ist , G 22   ist , G 23   ist of the component  21  for after-dosing or components  21 ,  22 ,  23  for after-dosing. The actual value G 20   ist , G 21   ist , G 23   ist is in particular the actual weight or a corresponding measure of the weight and volume or similar. The actual value G 20   ist , G 21   ist , G 22   ist , G 23   ist may for example be provided by the respective dosing system  10 ,  12 . Alternatively, corresponding detection means such as scales or similar may also be provided. The controller  14  receives the actual values G 20   ist , G 21   ist , G 22   ist , G 23   ist from the dosing systems  10 ,  12 . The controller  14  determines a content A of the target component  20 . The content A may be an absolute value or a relative value in relation for example to a total value, such as the total weight of the target component  20  and the further component  21  for after-dosing or further components  21 ,  22 ,  23  for after-dosing. The content A is thus determined depending on the actual value G 20   ist of the target component  20  and/or the actual value G 21   ist of the component  21  for after-dosing or further components  22 ,  23  for after-dosing. The content A is compared with a limit value T or a tolerance band T. If the content A lies within the permitted tolerance or permitted limit value T, no further after-dosing takes place. Otherwise, at least one of the components  21 ,  22 ,  23  for after-dosing is after-dosed. For this, new target values Z 21 , Z 22 , Z 23  are then determined, with which the components  21 ,  22 ,  23  for after-dosing are after-dosed. These new target values Z 21 , Z 22 , Z 23  then serve as nominal values for the dosing system  12 , which then after-doses the components  21 ,  22 ,  23  for after-dosing accordingly. Alternatively, as well as the components  21 ,  22 ,  23  for after-dosing, the target component  20  may also be dosed again. 
     The controller  14  in conjunction with an automated dosing system  10 ,  12 , is able to receive values from one or more external sources, process these and issue actuation commands (for example, in the form of corresponding nominal values). These values to be received may come from another software program (for example HMI/recipe management), a controller (for example a programmable controller for dosing), or from the programmable controller of the overall system. Alternatively, the values to be received may be entered in a module manually by a user. Examples of values to be received are for example nominal/actual values, in particular nominal/actual weights, permitted tolerances T, or the maximum total weight. Actuation commands may comprise the transmission of new nominal values Z 20 , Z 21 , Z 22 , Z 23  to the dosing systems  10 ,  12 . 
     The received values or actual values G 20   ist , G 21   ist , G 22   ist , G 23   ist may be processed by the controller  14 . Here, the controller  14  determines for example a deviation of the actual value from the nominal value, for example the deviation of the actual weight from the nominal weight. Also, the controller  14  could check individual values against predefined tolerances. Also, the controller  14  could determine the total weight. 
     The method replaces a conventional dosing process in which usually all components are dosed simultaneously to 100%. With the present method, only the target component  20  is dosed to the desired target value Z 20  (100%), and the other components  21 ,  22 ,  23  for after-dosing are however dosed to a lower percentage rate relative to the target value Z 21 , Z 22 , Z 23 , such as for example the nominal weight S 21   soll , S 22   soll , S 23   soll . This procedure ensures that the after-dosing can be carried out even if the target component  20  is under-dosed. Optionally however, a minimum of 100% for the target component Z 20  may be established, so that the target component Z 20  is dosed until 100% of the nominal weight is at least reached, and hence the after-dosing does not lead to failure to reach a specific nominal weight S 20   soll , S 21   soll , S 22   soll , S 23   soll of one or all components. The method proceeds for example as described in connection with  FIG. 2 . 
     In the flow diagram according to  FIG. 2 , in a first step  101  the target component  20  is dosed, as part of a dosing  30 , to a desired target value Z 20 , for example 100% in relation to desired nominal value S 20   soll (for example, target weight). As well as the target component  20 , at least one further component  21  is dosed. This component  21  for after-dosing is firstly dosed to a target value Z 21  with a lower value, for example 90% in relation to the desired nominal value S 21   soll . This takes place by dosing  31  of the component  21  for after-dosing. 
     In the exemplary embodiment, further components  22 ,  23  for after-dosing are dosed. Thus a further component  22  for after-dosing is firstly dosed to a lower target value Z 22 , for example 90% in relation to the desired nominal value S 22   soll , by dosing  32  of the component  22  for after-dosing. 
     Also a further component  23  for after-dosing is firstly dosed to a lower target value Z 23 , for example 90% in relation to the desired nominal value S 23   soll , by dosing  33  of the component  23  for after-dosing. 
     It is essential that only the target component  20  is dosed to the target value Z 20  of 100% in relation to the nominal value S 20   soll , while the other components  21 ,  22 ,  23  for after-dosing are dosed to a lower target value Z 21 , Z 22 , Z 23  (for example 90%, as in the exemplary embodiment) in relation to the nominal value S 21   soll , S 22   soll , S 23   soll , in particular the nominal weight. This procedure ensures that the after-dosing can also be carried out if the target component  20  is under-dosed. Optionally however, a minimum of 100% for the target component  20  may be established, so that the target component  20  is dosed until 100% of the nominal weight is at least achieved, and hence the after-dosing does not lead to failure to reach a specific nominal weight of one or all components. 
     When the dosing step  101  is complete, in a step  102  the true values or actual values are recorded, in the exemplary embodiment the actually dosed weight G 20   ist of the target component  20 , or G 21   ist , G 22   ist , G 23   ist of the components  21 ,  22 ,  23  for after-dosing. On the basis of the determined actual values G 20   ist , G 21   ist , G 22   ist , G 23   ist , the content A of the target component  20  is calculated (as an absolute value or as a percentage). 
     In a step  103 , the content A of the target component  20  is compared with a limit value T or range (minimum value/maximum value). If the content A lies within the predefined tolerance T or below the limit value T, the dosing process is ended in step  106 . Therefore no after-dosing takes place. 
     If the content of the target component  20  lies outside the tolerance T, new target values Z 21 , Z 22 , Z 23  are calculated for the components  21 ,  22 ,  23  for after-dosing in step  104 , and transmitted to the corresponding dosing system  12  as a new actuation command. 
     The new target values are determined according to step  104  as follows: 
     Factor f for after-dosing: 
         f=G 20 ist/S 20 soll    
     New permitted total value Gzul or Gges (for sampling  105 ): 
         Gges=f*E ( S 20 soll+S 21 soll+S 22 soll+S 23 soll ) 
     The new target values Z 21 , Z 2 , Z 23  (for step  104 ) of the component(s)  21 ,  22 ,  23  for after-dosing: 
         Zn=f*Gnist  (i.e.:  Z 21= f*G 21 ist, Z 22= f*G 22 ist, Z 23= f*G 23 ist ) 
     If the total weight Gzul (or the new total weight Gges as described above) is still not reached (sampling  105 ), the after-dosing process is started according to step  107 . Again, the actual values G 21   ist , G 22   ist , G 23   ist of the components  21 ,  22 ,  23  for after-dosing, or in some cases the actual value G 20   ist of the target component  20 , are sampled (step  102 ). Again, in step  103  it is checked whether the content A of the target component  20  lies within a range T. The already described steps  106  (if within the permitted tolerance band T) or  104  (outside the permitted tolerance band T with subsequent after-dosing) may follow. Alternatively, as well as the components  21 ,  22 ,  23  for after-dosing, the target component  20  could also be dosed again. 
     The described method is preferably used in dosing of active substances as possible target components  20  for pharmaceutical products. However, other possible applications are conceivable in which a plurality of components are dosed.