Abstract:
A device produces containers having an inner space divided into separate container chambers by at least one separating wall. An extruder extrudes a tube of a plasticized synthetic material from an annular gap between an outer nozzle ring and an inner nozzle core. The nozzle core is provided with a guide for synthetic material that is branched off from the annular gap. At at least one outlet port at one nozzle end, the branched-off synthetic material is issued and forms a continuous separating wall that extends within the extruded tube. The guide for the branched-off synthetic material is positioned in a zone of the annular gap located upstream of and at a distance form the outlet end of the outlet port.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for producing containers, with an interior divided by at least one partition into separate container chambers. An extruder extrudes a tube of plasticized synthetic material from the annular gap between the outer nozzle ring and the inner nozzle core. The inner nozzle core has a guide for the synthetic material branched off out of the annular gap and at least one end-side outlet slot from which the branched-off synthetic material emerges as a partition. The partition extends continuously within the extruded tube. A welding and molding means closes the end of the tube by welding. By producing a pneumatic pressure gradient acting on the tube, the tube is expanded and is placed against the molding wall of the molding to form the container. 
     BACKGROUND OF THE INVENTION 
     A device for producing a container divided by a partition into separate container chambers is disclosed in DE 1 179 356 A1. The guide for the synthetic material forming the inner partition, in the known device, has a direct connection between the downstream outlet opening of the annular gap and the outlet slot of small depth which extends diametrically in the nozzle core. Even if the friction conditions which prevail in the end area of the annular gap are kept within narrow limits to a corresponding setpoint, a uniform, desired material thickness of the partition formed can hardly be maintained in operation. When to improve the flow conditions, the outlet slot is formed with an enlarged cross section from its middle to both ends, thereby to the branching sites on the annular gap, the danger exists that the partition formed in the central area has a smaller thickness than in the edge areas. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a device for producing a container with an interior divided by at least one partition into separate container chambers, characterized by an improved operating behavior. 
     This object is achieved in the present invention by a guide for the branched-off synthetic material placed in the area of the annular gap which is located upstream at a distance from the outlet end of the outlet slot. 
     In this manner, the branching site for the synthetic material is located in an area of the annular gap, upstream relative to the mouth area. Therefore, the area in which the plastic column is moving towards the downstream outlet opening has a considerable pressure gradient. By simply choosing the distance between the branching site and the outlet opening, the desired optimum flow conditions are established for the synthetic material entering the slot. By using the higher pressure level prevailing upstream of the outlet opening, the desired supply of the outlet slot for the partition to be formed can then be guaranteed for the respective viscosity properties of the extruded synthetic material. 
     In one advantageous embodiment, the nozzle core, as the guide for the branched-off synthetic material supplied to the outlet slot, can have at least one transverse hole as a connection between the annular gap which surrounds the nozzle core and the respective outlet slot. To adapt to the different conditions, only nozzle cores with differently arranged and dimensioned transverse holes need to be prepared to satisfy the different material properties. 
     In another advantageous embodiment, the nozzle core has a core tip which is screwed to it on the end side with a central screw union. The outlet slot is formed in the core tip. The surfaces of the core tip and of the following part of the nozzle core facing one another form a funnel surface and a conical surface which surrounds the central screw union. They are located at a distance from one another, and form an inlet area extending obliquely to the lengthwise axis of the nozzle and surrounding the screw union core as the guide for the synthetic material to be branched off from the annular gap and to reach the outlet slot via assigned passages in the core of the screw union. In one such embodiment, adaptation to different circumstances is made especially simple by only the core tip being replaced or its being screwed to the following part of the nozzle core. The desired change of the cross section of the inlet area arises between the funnel surface of the core tip and the opposite conical surface. 
    
    
     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 preferred embodiments of the present invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
     FIG. 1 is a perspective view of a two-chamber container produced by a device according to the present invention, without the contents added; 
     FIG. 2 is a schematically simplified, side elevational view in section of a nozzle arrangement of an extruder unit for the device according to a first embodiment of the present invention; 
     FIG. 3 is an opened and schematically simplified side elevational view of a nozzle core of an extruder means for the device according to a second embodiment of the invention; 
     FIG. 4 is a side elevational view of a two-chamber container in which a closure for both chambers is molded onto the container neck and can be opened by a twist-off lock produced by a device according to the present invention; 
     FIG. 5 is a top plan view, partially in section of the container of FIG. 4; 
     FIG. 6 is a schematically simplified, side elevational view of a device according to one embodiment of the present invention, for forming a two-chamber container, the blow mold being shown open; and 
     FIGS. 7 to  9  are side elevational views of the device of FIG. 6, with the blowmold being closed and in different process steps in the formation, filling and closing of the container, respectively. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows in schematic form a container  19  produced by a device according to the present invention. The container has a continuous inner partition  21  which divides the interior of the container  19  into two chambers  23  and  25  separated fluid-tight from one another. FIGS. 2 and 3 show the important parts of an extruder  1  which interacts with a blow mold (not shown in these figures) and forms embodiments of the device of the present invention, for producing a container  19 , having a inner partition  21 , as shown in FIG.  1 . 
     FIG. 2 shows the end of the extruder  1  facing a blow mold (not shown). A nozzle ring  27  of the extruder receives a nozzle core  31  located coaxially to the lengthwise axis  29  of the nozzle. The tip  33  of the nozzle core, with the end area of the nozzle ring  27 , defines an annular outlet  35  from which extruded synthetic material emerges in the form of a tube. The molten synthetic material reaches the outlet  35  via an annular gap  37  formed between the nozzle ring  27  and the nozzle core  31 . As can be seen from FIG. 2, this annular gap  37  narrows at the transition between the core tip  33  and the part of the nozzle core  31  which follows upstream so that a retaining area  39  for the supplied synthetic material results. 
     The core tip  33  is screwed to the following, upstream part of the nozzle core  31  via a pin having an outside thread  40 . The surfaces of the core tip  33  facing one another and the following part of the nozzle core  31  are located at a distance from one another. The corresponding surface of the core tip  33  forms a funnel surface  41 . The facing surface of the remaining nozzle core  31  defines a conical surface  43 . These surfaces  41  and  43 , in the example shown, include an angle of incline of 65° or 60° relative to the lengthwise axis  29  of the nozzle, and form between themselves a guide for the synthetic material branched off from the annular gap  37 . The synthetic material enters at the branch site formed on the retaining area  39  between the surfaces  41  and  43 . Through the holes in the pin of the core tip  33 , which has an outside thread  40 , this branched-off synthetic material travels into an outlet slot  45  formed on the front side of the core tip  33 . From there, the branched-off synthetic material emerges as a web extending crosswise within the extruded tube. After expansion of the tube, the web forms the partition  21  in the molded container  19  (FIG.  1 ). On either side next to the outlet slot  45 , i.e. on both sides of the plastic web emerging from the outlet slot  45 , in the end surface of the core tip  33 , there is one outlet opening  47  each for support air. The openings are connected to a central air channel  51  via branch lines  49  formed in the pin having the outside thread  40 . 
     The air supplied from the air channel  51  via the outlet openings  47  is intended as support air which simply prevents the collapse of the extruded tube and its cementing to the web which forms the partition  21 . The container is expanded in the blow mold in an additional working step by means of a blowing and filling mandrel. In an analogous arrangement to the outlet openings  47  of the core tip  33 , the blowing and filling mandrel has blow openings for supply of expanding, preferably sterilized blowing air. These blow openings can also be used as fill openings for supply of contents to the container chambers  23 ,  25 . 
     FIG. 3 shows the front end section of a modified nozzle core  31 , without the nozzle ring  27  which surrounds it. In contrast to the above described example, the nozzle core  31  does not have a front core tip screwed on to form a guide for the synthetic material to be branched off in cooperation with the following part of the nozzle core. Rather, in the embodiment of FIG. 3, for the guide, a direct connection is between the end-side outlet slot  45  and the annular gap which surrounds the nozzle core  31  via transverse holes  53 . Holes  53  extend in the nozzle core  31  transversely to the lengthwise axis and are connected to the inner, i.e. upstream, end of the outlet slot  45 . The number and cross section of the transverse holes  53  are chosen such that the desired amount of synthetic material which has been branched off from the outer annular gap emerges from the outlet slot  45  as the web which extends crosswise within the tube and which forms the partition  21 . As in the above described embodiment, on either side next to the outlet slot  45  outlet openings  47  are provided for the support air supplied from the central air channel  51 . 
     In both embodiments shown in FIGS. 2 and 3, the thickness of the web emerging from the outlet slot  45  can be adjusted by choosing the ratio between the nozzle gap, i.e. the width of the annular gap  37  formed within the nozzle ring, and the width of the outlet slot  45 . In the example of FIG. 2, the distance between the funnel surface  41  and the conical surface  43  can also be varied for this adjustment. Likewise, the amount of narrowing of the gap on the retaining area  39  can be varied. 
     Reference is made to FIGS. 6 to  9 . The container  19  produced using the device of the present invention can, if so desired, be filled like conventional single-chamber containers while still within the blow mold  5  and before the head-side, top welding jaws  13  are moved together on the blow mold to mold the container neck  57  on the end side and optionally close it by welding. As indicated above, the two-chamber container  19  can be filled by a combined blowing and filling mandrel or by a filling mandrel which performs only the filling function. For each of the container chambers  23  and  25 , the mandrel has an outlet opening for the contents. The mandrel output openings are arranged offset in the same way relative to the lengthwise axis of the filling mandrel, as for the outlet openings  47  for support air on the nozzle core  31  of the extruder  1 . The outlet openings  47  discharge on either side next to the outlet slot  45  which forms the partition  21 . 
     As mentioned above, the shaping of the neck of the container produced using the process of the present invention is performed by top movable welding jaws  13  on the pertinent blow mold, see FIGS. 6 to  9 . In the example of the container  19  shown in FIG. 1, the outside thread  17  is produced for a closure in the form of a screw cap (not shown) which closes both container chambers  23  and  25 . 
     Instead of making one such screw closure, a different type of closure can be made by the upper welding jaws  13  in the shaping of the container neck, as is known in the pertinent technology for single-chamber containers, for example, according to the bottelpack® system. As is shown in FIGS. 4 and 5, a rotary lock closure can be molded on the container neck  57 . The welding process is carried out such that the two chambers  23  and  25  are closed by a twist-off lock  59 . Lock  59  can be separated at a disconnect  63 , formed as a scored site, by the lock being turned using its molded-on handle piece  61 . 
     FIGS. 6 to  9  show, in a highly simplified schematic, the progression of the process steps from the initial extrusion process of the synthetic material to complete production of a two-chamber plastic container, with two chambers  23  and  25  filled and hermetically closed by a rotary lock closure  73  (FIG.  9 ). FIG. 6 shows the extrusion of the tube  3 , with the inner partition  21 , into the opened blow mold  5 . FIG. 7 shows of the tube expansion into a container  19  by blowing air through the blowing mandrel  11  on either side of the partition  21  after the blow mold  5  has been closed. The bottom-side weld edges  7  carry out a hot-wire welding process by which the tube  3  is closed on the lower end and is joined to the end of the partition  21  on a weld seam  9 . 
     After withdrawing the blowing mandrel  11 , the filling mandrel  71  is inserted. The filling mandrel has one fill opening each for each container chamber  23  and  25  separated by the partition  21 . The two chambers  23  and  25  are now filled, while the container  19  is still located within the blow mold  5  (FIG.  8 ). 
     After completed filling, the filling mandrel  71  is withdrawn and the top welding jaws  13  are moved together to carry out another welding process on the container neck  57 . The container neck  57  is finally molded and, in the example shown, is provided at the same time with a closure which hermetically closes both chambers  23  and  25 . In the example shown in FIG. 9, a rotary lock closure  73  is formed so that the container neck is made in the manner as shown in FIGS. 4 and 5, where a twist-off lock  59  with a handle piece  61  is shown. Such twist-off lock makes it possible to twist off the lock  59  at a disconnect  63 , by which the two chambers  23  and  25  of the container  19  are opened. 
     After filling the container and withdrawing the filling mandrel  71 , if so desired, insert parts can be placed in the container neck  57  before hermetically sealing the container. They can be functional parts such as a drop insert, a rubber plug, a hollow needle or other foreign part which can be inserted by a vacuum gripper before the welding jaws are moved together to weld around the insert part and at the same time form a hermetic closure. 
     While the present invention is described above based on the production of a two-chamber container, the nozzle core  31  of the extruder  1  could have more than one outlet slot  45  to extrude more than one plastic web. Within the plastic tube, several partitions can then be formed, to either side of which blowing air is supplied to mold a multichamber container in the pertinent blow mold. 
     In the final execution of the container neck  57 , the two chambers  23  and  25  can each have their own closure. 
     While various embodiments have 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.