Abstract:
An apparatus for the fabrication of a container ( 300 ), comprising a mold defining the form of said container ( 300 ) and configured to accommodate a substantially tubular preform, an injection head ( 115 ) configured to interface with the preform and establish fluid communication with a cavity thereof; an injection valve ( 202 ) configured to selectively permit fluid communication through said injection head ( 115 ), and a stretching rod ( 117 ) slideably disposed within the injection head ( 115 ); said apparatus ( 100 ) further comprising a displacement plunger ( 209 ) being disposed coaxially about and mobile relative to said stretching rod ( 117 ) between a retracted position substantially within the injection head ( 115 ) and an extended position wherein said displacement plunger ( 209 ) projects at least partially from said injection head ( 115 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is the U.S. national phase of PCT Application No. PCT/EP2013/075628 filed on Dec. 5, 2013, which claims priority to EP Patent Application No. 12198181.5 filed on Dec. 19, 2012, the disclosures of which are incorporated in their entirety by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention concerns generally to an apparatus for the fabricating and filling of containers. The invention also relates to a method of employing said apparatus to fabricate and fill containers, as well as the container so produced. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is commonly known in the art of container fabrication to fabricate containers by the stretch blow molding process. In the stretch blow molding process, a substantially tubular parison or “preform” is provided, being fabricated from a thermoplastic and having an open end near a mouth and a closed end opposite the open end. The preform is disposed within a mold having a cavity substantially defining the form and contours of a container. 
         [0004]    The preform is expanded into the cavity of the mold by the action of a working fluid injected into the preform under pressure, and by the action of a stretching rod inserted into a mouth of the preform. The pressurized fluid causes the preform to inflate, expanding primarily radially. The stretching rod is advanced into the preform and presses against an opposite interior surface, stretching it longitudinally into the mold. 
         [0005]    Conventionally, the pressurized fluid injected during the molding of the container is air, usually heated to facilitate the deformation of the preform. However, it is known to use a liquid as the working fluid, preferably the liquid which is ultimately to be packaged within the container. In this way, the process of forming a container and filling it with a product are effectively combined, realizing great advantages in equipment cost and production efficiency compared to an air-injection stretch blow molding system. 
         [0006]    When filling a container with a liquid, it is necessary to leave a small void space at the top of the container. This void space enables the consumer to open the container without spilling any of the liquid contained therein, as well as provides compensation for any thermal expansion of the liquid during storage. 
         [0007]    In processes where the fabrication and filling of the container are carried out in separate steps, providing this void space is a relatively trivial matter. In a process so configured, one need only dispense a volume of liquid product into the container during the filling step that is less than the total volume of the container by the desired amount, leaving the necessary void space in the container. 
         [0008]    In a combined forming-filling container fabrication process, however, this is not a feasible option. Specifically, in order to ensure that the preform is fully expanded into the cavity of the mold and that all of the contours of the resulting container are fully formed, one must inject a volume of liquid equal to the full, final volume of the container. The resulting container is thus filled to the brim with the liquid product. 
         [0009]    When using a combined forming-filling process combined with a stretching step of the preform, the stretching rod does occupy some volume within the container, and retracting it at the completion of the forming-filling process will create a small amount of void space in the container. The void space created by the displacement of the stretching rod, however, is not always sufficient for the prevention of spilling when the container is opened, especially where a particularly thin stretching rod is employed. 
         [0010]    Increasing the diameter of the stretching rod will increase the volume of the void space ultimately created in the container; however, the space between the stretching rod and the interior surface of the mouth of the container are coordinately reduced, impeding the injection of the liquid during the forming of the container. It is therefore necessary to remove some of the liquid from the container upon the completion of the injection process. 
         [0011]    One solution to this is to remove a small amount of the liquid by suction, in particular by sucking some of the liquid back through the means for injecting it into the preform during the fabrication of the container. In particular, the document WO 2010/003853 Al describes a stretch blow molding system in which the stretching rod is hollow, and contains at least one port at a distal end through which this extra liquid may be aspirated from the beverage container. 
         [0012]    While this system produces acceptable filled containers, it is disadvantageous in several aspects. First, the at least one port in the stretching rod must remain sealed during the injection of the liquid, which increases the complexity of the apparatus and the expense of its manufacture and operation. Furthermore, the channel within the stretching rod is difficult and time-consuming to clean as the apparatus must be at least partially disassembled to give access to the entire channel. In addition, dissolved material in the liquid will tend to form accretions in the narrow channel and ports, a particularly acute problem when the liquid is mineral water. These accretions reduce the flow through the hollow stretching rod, requiring time-consuming cleaning and maintenance to maintain efficient functioning of the apparatus. 
         [0013]    It is therefore an object of this invention to provide a method for fabricating and filling a beverage container which accurately provides a void space in a formed and filled container without the disadvantageous aspects of the apparatuses known in the art. 
       SUMMARY OF THE INVENTION 
       [0014]    According, therefore, to a first aspect, the invention is drawn to an apparatus for the fabrication of a container, comprising a mold, said mold comprising a plurality of mold segments substantially defining a mold cavity in the form of a container, and being further configured to accommodate a substantially tubular preform having a closed first end and defining a preform cavity communicating with a mouth at an open second end; an injection head, said injection head configured to interface with the mouth of the preform and establish fluid communication between a liquid supply and said mouth; an injection valve, said injection valve configured to selectively permit fluid communication through said injection head; and a stretching rod slideably disposed within the injection head, said stretching rod being mobile relative to the preform along a longitudinal axis of said preform and configured to press against an interior surface of said preform at the closed first end thereof. 
         [0015]    According to the invention, said apparatus is characterized in that it further comprises a displacement plunger, said displacement plunger being disposed coaxially about and mobile relative to said stretching rod between a retracted position substantially within the injection head and an extended position wherein said displacement plunger projects at least partially from said injection head. 
         [0016]    This is advantageous in that an apparatus so configured will produce filled containers, each provided with an accurately-measured volume of liquid and void space, without encountering the disadvantageous aspects of the apparatuses known in the prior art. By providing a displacement plunger about the stretching rod, one realizes a very high degree of accuracy in the control over the amount of liquid expelled from the container and, more importantly, the amount of liquid remaining in the container. 
         [0017]    Specifically, the extension of the displacement plunger into the container renders the provision of a void space within the container more accurate, in that the volume of liquid expelled from the container is exactly equal to the combined volume of the portions of the stretching rod and displacement plunger which are inserted into the container, the extension of which being controlled with a high degree of precision. This realizes much more accurate results than the apparatuses known in the art which necessarily employ pumps, plumbing, flow meters, etc. in their operation, which each introduce the opportunity for variation and error in the volume of liquid extracted from the container. 
         [0018]    Furthermore, the provision of the displacement plunger renders the operation of the apparatus more reliable and economical than those known in the art, in that it eliminates the channel and ports within the stretching rod which are difficult and time-consuming to clean and are prone to clogging from accreted substances. 
         [0019]    According to another feature, the injection valve is disposed within the injection head coaxially with a nozzle of said injection head, said injection valve seating in said nozzle when in a closed position. 
         [0020]    This is advantageous in that the injection valve is integrated into the injection head. The entirety of the apparatus is thereby rendered more compact while also reducing the volume of the liquid channels of the apparatus between the nozzle of the injection head and the injection valve. The accuracy and responsiveness of the injection head and the flexibility of its disposition within the apparatus are both thereby improved. 
         [0021]    According to a feature, the apparatus further comprises a sealing means disposed between the stretching rod and the displacement plunger. 
         [0022]    This is advantageous in that the sliding joint between the stretching rod and displacement plunger will the protected from the infiltration of liquid from the container. This will prevent inaccuracies in the provision of the void space due to the improper expulsion of liquid from the container, as well as prevent corrosion and other wear due to the infiltration of the liquid. The accuracy and reliability of the apparatus is thereby improved. 
         [0023]    According to a second aspect, the invention is drawn to a method for the fabrication of a container, comprising the steps of providing a substantially tubular preform, said preform having a closed first end and defining a preform cavity communicating with a mouth at an open second end; disposing the preform at least partially within a mold comprised of a plurality of mold segments and being provided with a mold cavity substantially defining the form of a container; positioning an injection head upon the mouth of the preform, said injection head establishing fluid communication between said mouth and a liquid source, an injection valve selectively permitting fluid communication through said injection head; opening the injection valve and injecting a volume of liquid into the preform cavity of the preform after insertion of a stretching rod into the preform cavity through the mouth of the preform has began, said stretching rod being pressed into an interior surface of the closed first end thereof, said preform being thus induced to expand into the contours of the mold cavity and produce a container; inserting a displacement plunger into said container from a retracted position substantially within the injection head to an extended position projecting at least partially from said injection head, thereby displacing a portion of the volume of liquid and expelling it through said injection head; closing the injection valve, thereby blocking fluid communication between the fluid source and the container; and withdrawing the injection head, stretching rod, and displacement plunger from the container. 
         [0024]    This is advantageous in that fabricating a container by such a method will realize the advantages of the apparatus described above in the fabrication and filling of containers. This method produces fabricated and filled containers, ready for sealing, labeling, and distribution, without implicating the complex mechanisms required to remove liquid through a hollow stretching rod, nor the costly and time-consuming maintenance processes to maintain the cleanliness of and unimpeded flow through said hollow stretching rod. 
         [0025]    Furthermore, the insertion of a displacement plunger improves the control that may be exercised over the amount of liquid displaced from the container. Specifically, as the diameter of the stretching rod and displacement plunger are known and fixed, one may control the amount of liquid expelled from the container simply by controlling the advancement of the displacement rod into the container. The insertion of the displacement rod will thus obviate any flow-metering or other means for measuring the volume of liquid expelled from the container, at once simplifying the operation of the apparatus and ensuring that a consistent and accurate volume of liquid remains within the containers so produced. 
         [0026]    According to a third aspect, the invention is drawn to a container produced by the method as described above. This is advantageous in that such a container will embody the advantages of the method as described above. 
         [0027]    Other particularities and advantages of the invention will also emerge from the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    In the accompanying drawings, given by way of non-limiting examples: 
           [0029]      FIGS. 1A and 1  B are perspective depictions of an exemplary stretch blow molding apparatus, in a partially-exploded and assembled disposition, respectively; 
           [0030]      FIGS. 2A and 2B  are orthogonal section views of an injection head of the embodiment of  FIGS. 1  A and  1  B, having an injection valve that is closed in  FIG. 2A  and open in  FIG. 2B ; and 
           [0031]      FIGS. 3A through 3F  are a series of orthogonal section views depicting a container before, during, and after the insertion of a displacement plunger. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]      FIGS. 1A and 1  B are perspective views of an exemplary stretch blow molding apparatus  100  according to an embodiment of the invention.  FIG. 1A  depicts the apparatus in a partially-exploded disposition. The apparatus  100  comprises a base mold segment  101  and the two lateral mold segments  102 A and  102 B. The base mold segment  101  is provided with a base depression  103  substantially defining the base of a container, while the lateral mold segments  102 A and  102 B are respectively provided with the lateral depressions  104 A and  104 B, each substantially defining half of the body of a container. The base depression  103  and lateral depressions  104  together form the mold cavity  105 , which substantially defines the form of a container. 
         [0033]    The lateral depressions  104 A and  104 B each communicate with a top face  106  of their respective lateral mold segments  102 A and  102 B, cooperating to form a mold hole  107  communicating with the mold cavity  105 . Into the mold hole  107  is disposed a preform  108 , which is substantially tube-shaped and comprises a closed end  109  and a mouth  1   10  at an open end  111  communicating with a preform cavity  112  within said preform  108 . 
         [0034]    In this embodiment of the invention, the mold segments  101 ,  102 A, and  102 B are depicted as substantially independent components, each being capable of a full range of motion independent from the other two. It may be preferable, however, to provide linkages or other such connections between the mold segments so as to restrict their range of motion relative to each other, or to provide that the mold segments are linked together by means such as rails or sliders. 
         [0035]    In  FIG. 1A  the preform  108  is shown removed from the mold cavity  105  for clarity; however, it should be understood that the preform  108  is disposed so that it is substantially within the mold cavity  105 . Preferably, the preform  108  is provided with a flange  113 , which will rest on the top faces  106  of the lateral mold segments  102 . The top faces  106  may be further provided with a preform seat  114  disposed about the mold hole  107 , which locates the flange  113  of the preform  108 , positioning and centering the preform  108  within the mold cavity  105 . 
         [0036]    Preferably, the open end  111  of the preform  108  protrudes from the top faces  106  of the lateral mold segments  102 A and  102 B, while the rest of the preform  108  is thus disposed within the mold cavity  105  defined by the base depression  103  and lateral depressions  104 . 
         [0037]    The apparatus  100  further comprises an injection head  115 . The injection head  115  is provided with a nozzle  116  which is configured to mate with the mouth  110  of the preform  108  and create a fluid-tight seal therewith. The injection head  115  is further provided with a stretching rod  117 , here depicted slightly extended from the nozzle  116 . The injection head  115  is connected to a fluid supply  118 , such that a volume of fluid may be conducted from said fluid supply  118  through the injection head  115  and out the nozzle  116 . The fluid supply  118  is controlled by an injection valve, which may be disposed within the injection head  115  as here, or optionally outboard of the injection head, for example in a pumping unit or other such fluid handling system. Furthermore, In  FIG. 1A , the injection head  115  is affixed by the arm  119  to a positioning mechanism, such that it may translate in each of the six principal axes  120  and position itself upon the mouth  110  of the preform  108 . However, it should be understood that the injection head  115  need not necessarily be so configured: depending on the integration of the molding apparatus  100  into the production line as a whole and the configuration of the molding apparatus in particular, it may only be necessary to provide, for example, a means for the injection head  115  to translate along a vertical axis relative to the mold segments  101  and  102 . The exact configuration of the apparatus may be determined by one skilled in the art, according to the particular demands of the implementation. 
         [0038]      FIG. 1B  depicts the mold apparatus in an assembled disposition, with the mold segments  101 ,  102 A, and  102 B brought together in abutment to form the mold  121  which defines the mold cavity  105 . The preform  108  is disposed substantially within the mold cavity  105 , and the injection head  115  is positioned over the mouth (not shown) of the preform  108  which protrudes from the mold cavity  105 . At this point, the injection head  115  is ready to inject a quantity of liquid into the preform  108  and expand it into the contours of the mold cavity  105 , forming a container. 
         [0039]      FIGS. 2A and 2B  depicts a section view of the injection head  115  according to the embodiment of the invention of  FIGS. 1A and 1B .  FIG. 2A  depicts the injection head  1   15  in a closed state as prior to an injecting step, and  FIG. 2B  depicts the injection head  1   15  in an open state as during an injection step. 
         [0040]    As shown in  FIGS. 2A and 2B , the injection head  115  comprises an outer shell  200 , comprising generally a body section  201  and the nozzle  116 , the latter being configured to mate with the mouth  110  of the preform  108  and communicate with a preform cavity  112  within said preform  108  as described above. The injection head further comprises the injection valve  202 , disposed within the outer shell  200  and defining the injection head cavity  203  between the two. The injection head cavity  203  is thus provided in fluid communication with the nozzle  201 . 
         [0041]    The injection valve  202  is comprised of the valve body  204  which is provided with a taper  205  at said nozzle  201 , and a valve seat  206  formed from a portion of an inner wall  207  of the outer shell  200  configured to mate with the taper  205 . When in the closed position as shown in  FIG. 2A , the valve body  204  will thus block fluid communication between the injection head cavity  203  and the preform cavity  112 . 
         [0042]    In some embodiments, it may also be advantageous to provide the injection head  1   15  with a means for sealing the joint between it and the preform  108 , ensuring fluid-tightness between the two. In other embodiments, as here, the fluid-tightness between the injection head  115  and the preform  108  is furnished by the force  208  with which the injection head  115  is pressed into the preform  108 . 
         [0043]    The injection head  115  is also provided with a displacement plunger  209  about the stretching rod  117 . The stretching rod  117  is disposed coaxially within the displacement plunger  209 . The stretching rod  117  and displacement plunger  209  are both disposed coaxially within the valve body  204  and are configured to be independently mobile relative to both the valve body  204  and each other. The valve body  204  is itself disposed coaxially with the valve seat  205  and the nozzle  201 , such that the entire group of nozzle  201 , valve body  204 , valve seat  205 , displacement plunger  209 , and stretching rod  117  are disposed in alignment along the longitudinal axis  211 . The displacement plunger  209  and stretching rod  117  are preferably displaced by an electric actuator, though other means such as hydraulic cylinders, pneumatic actuators, and the like may alternately be employed. 
         [0044]      FIG. 2A  shows the injection head  115  prior to an injecting step. The valve body  204  is seated in the valve seat  206 , blocking fluid communication through the injection head  115  and preventing flow of the liquid  212  through the nozzle  201 . Both the stretching rod  117  and the displacement plunger  209  are fully retracted within the injection head  115 . 
         [0045]    Preferably, there is a sealing means  213  disposed at the joint between the stretching rod  117  and the displacement plunger  209 . This may take the form of a circumferential rod seal, as here, or alternately other sealing means may be employed as appropriate to the construction of the apparatus. 
         [0046]      FIG. 2B  shows the injection head  115  during an injecting step. The stretching rod  117  is advanced into the cavity  112 . The stretching rod  117  is advanced into the closed end (not shown) of the preform  108  and causes the preform to stretch along the longitudinal axis  211 . 
         [0047]    Shortly thereafter, the valve body  204  is retracted from the valve seat  206 , permitting the liquid  212  to flow through the nozzle  201  of the injection head. The liquid  212  is injected with a flow  214  into the cavity  112  of the preform  108 , further expanding the preform  108  and causing it to assume the form of the mold cavity (not shown) in which it is disposed. The displacement plunger  209 , however, remains in its retracted position throughout the injecting step. 
         [0048]      FIGS. 3A to 3F  are a series of section views which detail the operation of the injection head  115  of the embodiment during a process for fabricating and filling a container  300 . 
         [0049]      FIG. 3A  depicts the injection head  115  and container  300  immediately following the completion of its fabrication. The stretch rod  117  has been advanced to its fully-extended position, but the valve body  204  remains retracted from the valve seat  206  and fluid communication is still maintained between the injection nozzle and the container cavity  301  of the container  300 . The container  300 , having been completely formed during the injection step, is filled with the liquid  302 . 
         [0050]      FIG. 3B  depicts the injection head  115  and container  300  during a step for inserting a displacement plunger  209 . The displacement plunger  209  is advanced into the container cavity  301  of the container  300 , inducing a portion of the liquid  302  to be expressed from the container cavity  301  and into the injection head  115 . The liquid  302  is expressed in a flow  303 , which proceeds from the container cavity  301  through an annular gap  304  between the displacement plunger  209  and the mouth  305  of the container  300 . 
         [0051]      FIG. 3C  depicts the injection head  115  and container  300  at the conclusion of the step for inserting the displacement plunger  209 . The displacement plunger  209  is in its extended position, having expelled a desired volume of the liquid  302  from the container and leaving the rest therein. 
         [0052]    The volume of the liquid  302  which is expelled from the container will vary with the degree to which the displacement plunger  209  is advanced into the cavity  301  of the container  300 . One may thus adapt the process to the characteristics of the container sought to be fabricated, in part by altering the extension of the displacement plunger  209 . 
         [0053]    For instance, the same injection head may be employed to fabricate containers of different volumes by altering the extension of the displacement plunger during the step for inserting the displacement plunger into the container, such that the displacement plunger is extended to a greater degree when fabricating larger containers where a greater volume of liquid must be expressed to provide the proper void space, and to a lesser degree when fabricating smaller containers requiring less expression of liquid. 
         [0054]    In any event, however, the volume of liquid expelled from the container  300  will be substantially equal to the combined volume of the portions of the displacement plunger  209  and stretching rod  117  which extend into the cavity  301  of the container  300 . 
         [0055]      FIG. 3D  depicts the injection head  115  and container  300  during a subsequent step for closing the injection valve within the injection head  1   15 . The valve body  204  is advanced into the valve seat  206 , thereby preventing fluid communication between the injection head cavity  203  and the container cavity  301 . While  FIGS. 2A ,  2 B, and  3 A through  3 F depict an embodiment where the injection valve is incorporated within the injection head, it should be understood that the injection valve may be positioned elsewhere in the container fabrication apparatus, so long as when it is closed it prevents any further flow of liquid into the container. For instance, it may be advantageous to instead provide the injection valve outboard of the injection head, such as in a liquid reservoir or pumping unit. The exact disposition of the components of the container fabricating apparatus may be determined by one skilled in the art according to the particularities of each installation. 
         [0056]      FIG. 3E  depicts the injection head  115  and container  300  during a step for withdrawing the injection head  115 , displacement plunger  209 , and stretching rod  117  from the container cavity  301  of the container  300 . The injection head  115  is first slightly withdrawn from the mouth  305  of the container  300 , permitting communication between the container cavity  301  and the surrounding atmosphere. The displacement plunger  209  is then subsequently withdrawn from the container cavity  201 , returning to its initial, fully-retracted position as depicted in  FIG. 2A . The level of the liquid  302  within the container  300  is thus lowered by the distance  307 . 
         [0057]      FIG. 3F  depicts the injection head  115  and container  300  after the completion of the step for withdrawing the injection head  115 , displacement plunger  209 , and stretching rod  117 . Both the displacement plunger  209  and the stretching rod  117  have returned to their initial, fully-retracted positions as depicted in  FIG. 2A , leaving the second void space  308 . The withdrawal of the stretching rod  209  will cause the liquid to drop further, receding from the mouth  305  of the container  300  by the distance  309 . 
         [0058]    In an exemplary implementation of the method of the invention, the volume of the void space  308  is approximately 10 percent of the volume of the liquid  302  remaining in the container  300 , or 1/11th of the total interior volume of the container itself. However, this may of course be altered according to the characteristics of the particular container being fabricated, by varying the length by which the displacement plunger  209  is inserted into the container cavity  301  of the container  300 . In this way, one may exercise a great deal of control over the exact volume of the liquid  302  remaining in the container  300 , whatever the size of the container  300 . 
         [0059]    The container  300  as shown in  FIG. 3F  is thus filled with the desired volume of liquid  302  and the proper void space  308 , and may be conducted to further apparatuses to be sealed or capped, labeled, and/or packaged for distribution. 
         [0060]    Of course, the invention is not limited to the embodiments described above and in the accompanying drawings. Modifications remain possible, particularly as to the construction of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention. 
         [0061]    In particular, the exact sizes and shapes of the elements discussed in the foregoing description may be varied according to the particularities of the application in which the invention is to be employed. For instance, the dimensions and configuration of the injection head, injection valve, displacement plunger, and stretching rod may be adapted to achieve optimal results in any particular application, while still embodying the inventive principle of this invention. 
         [0062]    The exact configuration and operation of the invention as practiced may thus vary from the foregoing description without departing from the inventive principle described therein. Accordingly, the scope of this disclosure is intended to be exemplary rather than limiting, and the scope of this invention is defined by any claims that stem at least in part from it.