Abstract:
A device for filling containers includes an arrangement ( 7 ) for feeding filling material to at least one dosing system ( 5 ) forming a flow path ( 27 ) containing a dosing valve ( 29 ) that can be opened at least for the duration of the dosing processes to distribute the dosing amounts of the filling material via at least one filling line ( 9 ) into relevant containers. The dosing system ( 5 ) has an element ( 31, 33, 43 ) disposed in the flow path ( 27 ) downstream of the dosing valve ( 29 ) for selectively producing a suction effect in the flow path ( 27 ). A control mechanism ( 39 ) activates the element ( 31, 33, 43 ) producing the suction effect. Dosing processes are completed by closing the dosing valve ( 29 ).

Description:
FIELD OF THE INVENTION 
     The invention relates to a device for filling containers, comprising an arrangement for feeding filling material to at least one dosing system forming a flow path in which there is a dosing valve. The dosing valve can be opened at least for the duration of the dosing processes to deliver the dosing amounts of the filling material to the pertinent containers by at least one filling line. 
     BACKGROUND OF THE INVENTION 
     In the pertinent prior art, a system economically enabling automated molding (blow molding or vacuum molding), filling, and sealing of containers is known under the trademark Bottelpack®. When the containers are to be filled with sensitive products, for example, pharmaceuticals, the international standards for aseptic packaging must be satisfied and during each filling process a specific dosing amount must be filled in each container. The quantity of the filling amount must be maintained with the greatest precision, especially when highly efficacious pharmaceuticals are involved. 
     To meet these requirements, in a device disclosed in document EP 0 418 080 B1, for each filling line assigned to a pertinent container to be filled, a dosing valve opens and closes in a time-controlled manner by electromagnetic actuation. The opening time for each dosing process is chosen such that at a set buffer pressure of the filling material is available in a dosing distributor. The desired dosing amount flows through the dosing valve during the opening time. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved filling device of the aforementioned type which is characterized by increased dosing accuracy compared to the prior art. 
     This object is basically achieved according to the invention by a device where, downstream of the dosing valve, a control is provided by which a suction action can be produced on the flow path when the respective dosing processes are completed. Specifically, the suction action is produced when the pertinent dosing valve closes. When the dosing process is ended, in the filling line, this suction action causes return suction of the remaining liquid out of the filling line or at least prevents dripping of liquid afterwards. A maximum of dosing accuracy certainly can be achieved in this way. 
     In advantageous exemplary embodiments, between the dosing valve and the filling line a choke site constricts the flow path during the dosing processes, In the region of the choke site, a movable control element defines the width of the flow path depending on its position setting and can be transferred into a position which widens the flow path at the choke site by forming a bypass when the suction device is activated. The choke site interacts with the time control of the opening time of the dosing valve to determine the dosing amount. In interaction with the control element defining the width of the flow path, the choke site also forms a part of the suction action device having an operating principle of the movable control element forms a widening in the flow path as a bypass of the choke site. This arrangement results in an enlargement of the inside volume of the flow path, and thus in an afterflow effect. 
     Advantageously, the suction action device is formed by a bypass valve being a diaphragm valve whose diaphragm forms the movable control element. One closing side of the control element delimits the flow path at the choke site. On the other control side of the control element, a negative pressure can be applied for producing a suction action to cause the diaphragm to execute a deflection motion which widens the flow path. This lift of the diaphragm produces the suction action on the filling line. In these exemplary embodiments the means which produces the suction action device is characterized by an especially simple construction. 
     The dosing valve can also be formed by a diaphragm valve in a correspondingly advantageous manner. 
     An especially compact and simple structure of the dosing system can be achieved when the dosing valve and the downstream bypass valve are diaphragm valves controlled by a joint diaphragm extending along the flow path. 
     To support the movement of the diaphragm both at the dosing valve and at the bypass valve into the rest position, i.e., into the respective closed position, and to elicit deflection movements out of the rest position, on the control side of the diaphragm opposite the closing side alternately an overpressure as the closing pressure and an underpressure as the opening pressure can be applied to the pertinent dosing valve and to the pertinent bypass valve by assigned control lines. 
     Advantageously, a plurality of filling lines have respectively assigned dosing units combined in a dosing block. The input sides of the respective dosing valves are connected to a common distributor of the filling material under a set buffer pressure. 
     In such design, in the dosing block, a diaphragm is assigned to the dosing valves and bypass valves and is common to the dosing system as a whole. 
     In operation with this dosing block, the diaphragm can be triggered jointly on the bypass valves from a common control line, while for the control sides of the diaphragm on the dosing valves, each filling line has its own control line for pressure and negative pressure. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings which form a part of this disclosure: 
         FIG. 1  is a side elevational view of only the dosing block with the pertinent distributor of filling material of a device according to an exemplary embodiment of the invention, which view is approximately half-size compared to a practical embodiment; 
         FIG. 2  an end elevational view in section enlarged compared to  FIG. 1  and taken along line II-II of  FIG. 1 ; 
         FIG. 3  is a schematically simplified, end elevational view in section of a device for producing and filling containers, one filling line being shown which is connected to the pertinent filling line output of the dosing block of in  FIGS. 1 and 2 ; and 
         FIGS. 4   a  to  4   d  are schematic end elevational views illustrating the construction and manner of operation of the dosing valve according to the exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is explained below using one example in which the device contains a plurality of dosing systems. Specifically according to  FIG. 1 , fifteen dosing systems  5  are combined in a common dosing block  1 . From a common distributor of filling material  3  in which the liquid to be filled in is under a set buffer pressure, each of the dosing systems  5  within the dosing block  1  receives the liquid filling material via a feed line  7 , only a few of these lines are numbered in  FIG. 1 . In the course of operation, the dosing systems  5  deliver the dosing amounts to a corresponding filling line  9  (likewise not all numbered in  FIG. 1 ). Each filling line  9  leads to a device (not shown) in  FIG. 1 , for producing and filling containers, for example, a device according to the known Bottelpack® system. 
     Of this device, only  FIG. 3  schematically shows a production and filling unit. As is apparent from this figure, each of these systems has a filling mandrel  11  on whose end, which is at the top in the figure, there is a supply head  13  for supply of channels in the filling mandrel  11  with media. As  FIG. 3  shows, on the supply head  13  the pertinent filling line  9  is connected to a filling material channel  15  extending centrally in the filling mandrel  11 . The filling material supplied, dosed by the respective filling lines  9 , emerges on the lower, fill needle-shaped end  17  of the filling mandrel  11  for filling of a respective container  19 . Container  19  is formed in a forming device  21  according to the aforementioned Bottelpack® system from plastic tubing  23  produced by an extruder head  25  from plasticized plastic material. 
       FIGS. 2 and 4  show details of the dosing units  5  combined in the dosing block  1 . As is apparent, on a flow path  27  extending between the feed line  7  and filling line  9 , two valves are connected in succession, specifically an upstream dosing valve  29  and a bypass valve  31  conversely located downstream. Both valves are diaphragm valves with a diaphragm  33  pneumatically controlled for deflection and resetting movements. The diaphragm  33 , preferably made from a plastic material such as PTFE or a rubber material, is common to both valves  29  and  31  of a dosing system  5 , and also common to all dosing systems  5  contained in the dosing block  1 ; i.e., the diaphragm  33  extends over the longitudinal area of the dosing block  1 . Each dosing valve  29  has its own pneumatic connection  35  for individual application of positive pressure or negative pressure to the control side  37  on the respective dosing valve  29 . In  FIG. 1  not all of the pneumatic connections  35  are numbered. The bypass valves  31  all have a pneumatic connection  39 , which is common to them to apply a positive pressure or a negative pressure to the control side  37  of the diaphragm  33  on the respective bypass valve  21 . 
       FIGS. 4   a  to  4   d  best illustrate how the dosing systems  5  work. As shown, on the dosing valve  29  and bypass valve  31  on the control side  37  of the diaphragm  33  there is a spherical cap-shaped space  43  into which a surface region of the diaphragm  33  can be deflected when negative pressure is applied to the control side  37  by the pneumatic connections  35  or  39 . The opposite closing side  45  of the diaphragm  33  is raised out of the closed position and deflected into the respective space  43  by the negative measure. This deflection causes opening of the pertinent valve  29  or  31 .  FIG. 4   a  shows the dosing valve  29  in the closed position, while the bypass valve  31  is opened.  FIG. 4   b  shows the dosing valve  29  open, while the bypass valve  31  is closed.  FIG. 4   c  shows both valves  29  and  31  in the closed position, while  FIG. 4   d  in turn shows the dosing valve  29  closed and the bypass valve  31  open. On the bypass valve  31  there is a respective choke site  41  on the flow path  27 .  FIG. 4   a  shows the rest position of the system prior to the respective dosing process, the dosing valve  29  still being closed while the bypass valve  31  is in the open position. In this open position of the bypass valve  31  in which the diaphragm  33  is deflected into the spherical cap-shaped space  43 , the flow path  27  is significantly widened compared to the state with the bypass valve  31  closed according to the volume of the respective chamber  43 . With the bypass valve  31  open, passage not only via the choke site  41  is thus available to the flow path.  FIG. 4   b  illustrates the dosing process in which the dosing valve  29  is opened, while the bypass valve  31  is closed so that the size of the passage of the choke site  41  in conjunction with the time-controlled length of opening of the dosing valve  29  determines the dosing amount. 
       FIGS. 4   c  and  4   d  illustrate the completion of the dosing process by closing of the dosing valve  29  ( FIG. 4   c ). After completed closing of the dosing valve  29 , the bypass valve  31  is opened as shown in  FIG. 4   d . The corresponding deflection motion of the diaphragm  33  into the spherical cap-shaped space  43  leads to a considerable widening of the flow path  27  at the bypass valve  31 . This lifting motion of the diaphragm  33  with the dosing valve  29  closed produces a suction action which causes return suction of liquid from the downstream filling line  9 . 
     As already mentioned, the dosing amount is determined by time control of the duration of opening of the respective dosing valve  29  via the individual pneumatic connection  35 . The suction action on the filling lines  9  can be produced simultaneously for all dosing systems  5  by the pneumatic connection  39  which is common to them being triggered. 
     For conventional cleaning and sterilization measures as are carried out conventionally before the start of the production phases, the dosing valves  29  and the bypass valves  31  are controlled into the open position. Thus, the unchoked flow path  27  is available for throughflow of cleaning and sterilization media, originating from the distributor of filling material  3  via the feed line  7 , dosing system  5 , and filling line  9  to the filling material channel  15  of the pertinent filling mandrel  11 . 
     While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.