Abstract:
A fluid flow connector and a method of manufacturing the same wherein the fluid flow connector utilizes a valve having a plunger which is made by overmolding a soft exterior to a hard core. The soft exterior being overmolded to the hard core by either insert or multi-shot methods. The method also including attaching the soft exterior to the hard core mechanically and/or by molecular bonding.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. Ser. No. 11/312,884, filed Dec. 20, 2005, now U.S. Pat. No. 8,091,864 issued Jan. 10, 2012, the entire contents of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The invention relates generally to flexible packaging and more specifically to the fluid connectors used to connect the flexible packaging to their end uses. 
     BACKGROUND OF THE INVENTION 
     A number of flexible plastic containers are well known in the art for storing and dispensing wine, soft drink syrup, dairy products, enteral feeding solutions, fruit juices, tea and coffee concentrates, puddings, cheese sauces, cleaning chemicals and many other flowable materials. The flexible containers described above typically have walls fabricated from polymeric films having either a monolayer or multiple layer structure. The particular polymers constituting the container film layers will often vary depending upon the type of material to be placed in the container. 
     In some instances, the film layers may additionally include an oxygen barrier material layer to prevent contact between such materials and oxygen or other gas sensitive contents. In some applications, the walls of the containers may be metallized, or coated with a metallic layer such as aluminum to prevent incursion of oxygen or other gases. A separate metallized enclosure may also encase the polymeric container. 
     These flexible polymeric containers  1  generally have inlets and/or spouts  2  for filling and dispensing the contents ( FIG.8 ). The spout typically includes a flange which is sealed to an inside surface of one of the walls of the container. In most applications, the containers are then placed within a corrugated box. The spout extends through an opening provided in the box to dispense the contents. Such packaging systems are commonly referred to as “bag-in-box”or BIB. Bag-in-box systems have enjoyed wide success in a number of industries, most notably for use in containing and dispensing soft drink syrup and other liquid products. Prior art examples of such systems of such systems are shown in U.S. Pat. Nos. 4,286,636; 4,601,410; 5,647,511; 5,749,493; and 6,607,097, the entire disclosures of which are incorporated herein by reference. 
     The BIBs which are used to store and dispense soft drink syrup typically use fluid flow connectors to connect the containers to fountain dispensing machines. The fluid flow connectors generally have valves that remain closed until the connectors are attached to the spouts of the containers. Such valves include plungers that fit into the inlet of the fluid flow connector so as to regulate the flow of the soft drink syrup. 
     The plunger includes a member which is made of a hard plastic and an O-ring that is fitted to a distal end of the member. When the fluid flow connector is not attached to a BIB, the plunger is biased towards a closed position with the O-ring being pushed against the inlet of the fluid flow connector to provide a fluid tight seal. When the fluid flow connector is attached to a BIB, the spout of the BIB causes the plunger to be pushed away from the inlet thereby allowing fluid to flow through the inlet. 
     The O-rings which are used in BIB systems for dispensing soft drink syrup are made of ethylene propylene diene monomer or “EPDM”. It has been discovered by the applicant that, when the fluid flow connectors described above are attached to BIBs containing syrup for diet soft drinks, the O-rings swell. This swelling causes the fluid connectors to leak because the O-rings can no longer provide a fluid tight seal when the connectors are not connected to the containers. The leaking fluid flow connectors also lets air into the fountain dispensing machines, causing a loss of vacuum or suction and, in some cases, an adverse effect on the taste of the dispensed soft drinks. The swelling of the O-rings additionally creates another problem; the swollen O-rings decrease the flow rate through the fluid flow connectors when the connectors are attached to the spouts of containers and fluid is being dispensed from the containers. 
     For example, one study performed by the applicant showed that the EPDM O-ring used with existing fluid flow connectors swelled to 0.05 inches in a matter of weeks when it was exposed to diet soft drink syrup at elevated temperatures. This same swelling occurs over a matter of months for EPDM O-rings exposed to diet soft drink syrup at ambient temperatures. As a result of the swelling of the O-rings and the subsequent leakage of syrup, a large number of service calls are made by the syrup suppliers to replace the fluid connectors, plungers and/or the O-rings. 
     The above-described problems generate increased operating costs for the soft drink syrup suppliers who have to make additional service calls to soda fountain retailers to repair leaking fluid flow connectors. Moreover, fountain soda retailers incur increased operating costs because of the clean-up of leaked syrup caused by the leaking fluid connectors. The retailers also lose sales of diet fountain soda while waiting for the leaking fluid flow connectors to be repaired or from the connectors not being able to dispense the syrup properly. 
     The present invention is designed to provide advantages over the presently used system described above. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a fluid flow connector that is coupled with the spouts of fluid containers to overcome the problems associated with prior art fluid flow connectors. The present invention also includes a method of manufacturing the fluid flow connectors. 
     The present invention includes a fluid flow connector that utilize a valve having a plunger that has a soft exterior which is overmolded to a hard core. The soft exterior replaces the EPDM O-rings that are used in the prior art to provide fluid tight seals with the inlet of fluid flow connectors. The present invention, thus, does not have the above-described problems associated with the prior art fluid flow connectors. 
     One embodiment of the present invention includes a fluid flow connector having an adapter for attaching the fluid flow connector to a spout of a fluid container. The fluid flow connector also includes a valve that is actuated to allow flow through the connector when the connector is attached to the spout of the fluid container. The valve includes a plunger that has a hard core and a soft exterior that is overmolded to the hard core. The hard core of the plunger is made of a thermoplastic material and the soft exterior is made of a thermoplastic elastomer that will provide a fluid tight seal with the inlet of the fluid flow connector. 
     One of the advantages of the present invention is that because the plunger is formed by overmolding, EPDM O-rings do not have to be used in the valve to provide a fluid tight seal with the inlet of the fluid flow connector. The present invention can thus provide a fluid flow connector that does not utilize EPDM O-rings which have a tendency to swell when the fluid flow connectors are used in applications having diet soft drink syrup. 
     For example, in one study completed by the applicant, plungers were manufactured for fluid flow connectors consisting of soft exteriors made of Santoprene™ TPV 271-55 which were overmolded to hard cores made of polyoxymethylene copolymer. The results of the study showed that the soft exteriors of the plungers embodying the present invention had significantly less swelling than did the EPDM O-ring of prior art plungers when the fluid connectors were used in applications having diet soft drink syrup. The present invention can thus be utilized for a significantly longer period of time without encountering the problems which occur from connectors having swollen O-rings. 
     It should be appreciated that the present invention is not limited to the above-described materials. Depending on the applications, other suitable materials may be used to manufacture the present invention. 
     It should also be understood that the term “overmolding” encompasses both insert and multi-shot molding processes. The present invention incorporates both techniques. For example, in one embodiment of the present invention, the hard core of the plunger is molded first and then transferred to second mold where the soft exterior is shot around one of the distal ends of the hard core. This technique is referred to as insert molding. 
     In another embodiment of the present invention, a multi-shot molding technique is used. In this embodiment, a press with multiple barrels is used, allowing the materials used for both the soft exterior and the hard core to be shot into the same mold. 
     The present invention also includes different methods of attaching the soft exterior to the hard core to form the plunger. In one embodiment of the present invention, the hard core is first formed. Then, once the hard core is cured, the soft exterior is overmolded to the hard core. The second overmolding of the soft exterior to the hard core occurs within a reasonable time subsequent to the molding of the hard core, so that the soft exterior tends to molecularly bond to the underlying hard core and form a single unit. 
     In another embodiment of the present invention, the hard core of the plunger is formed with at least one opening or aperture at the distal end of the hard core where the soft exterior will be overmolded to. The soft exterior can then be overmolded to the core at any time after the hard core has been formed. The soft exterior of the plunger is injected so that the soft exterior forms around the apertures and may be mechanically attached to the hard core of the plunger. 
     It should be appreciated that the soft exterior of the plunger can be overmolded to the hard core so that it is both mechanically attached and molecularly bonded to the hard core. 
     Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which: 
         FIG. 1  is a cross section side view of an uncoupled fluid flow connector embodiment of the present invention; 
         FIG. 2  is a perspective view of a plunger of an embodiment of the present invention; 
         FIG. 3  is a cross section side view of a prior art fluid flow connector; 
         FIG. 4  is a perspective view of a prior art plunger which includes an O-ring; 
         FIG. 5  is a perspective view of a hard core of a plunger of an embodiment of the present invention; 
         FIG. 6  is a cross-sectional view of a hard core of the plunger of  FIG. 5  without a soft exterior portion; 
         FIG. 7  is a cross-sectional view of the hard core of the plunger of  FIG. 5  having the soft exterior portion; and 
         FIG. 8  is a schematic view of a flexible bag and spout. 
     
    
    
     DETAILED DESCRIPTION 
     While this invention includes embodiments in many different forms, the embodiments shown in the drawings and described herein are preferred embodiments. Those preferred embodiments are to be considered exemplifications of the principles of the invention and are not intended to limit the broad aspect of the invention to the embodiments illustrated and described herein. 
     The present invention is directed to a fluid flow connector  10  having an adapter  12  for attaching the fluid flow connector  10  to a spout of a fluid container. One embodiment of the present invention is illustrated in  FIG. 1 . The fluid flow connector  10  also includes a valve  14  that is actuated to allow flow through the connector  10  when the connector  10  is attached to the spout of the fluid container. The valve  14  includes a plunger  16  that has a hard core  18  and a soft exterior  20  that is overmolded to the hard core  18 . One embodiment of plunger  16  is illustrated in  FIG. 2 . In that embodiment of the present invention, the hard core  18  of the plunger  16  is made of a thermoplastic material and the soft exterior  20  is made of a thermoplastic elastomer that will provide a fluid tight seal with the inlet  22  of the fluid flow connector  10 .  FIG. 1  illustrates the fluid flow connector  10  in the closed position with the soft exterior  20  of plunger  16  forming a fluid tight seal with inlet  22 . 
       FIGS. 1 and 2  show plunger  16  having a proximal end  50  and a distal end  30 . The hard core  18  of the plunger has a first annular flange  52  and a second annular flange  54  axially spaced from the first annular flange  52  to define an annular channel  53  therebetween. The soft exterior  20  is positioned within the annular channel  53 . An aperture  28  is positioned at the distal end  30  of the plunger  16  and extends axially through a portion of the rod to a pair of radially extending annular openings  32  with outlets positioned within the annular channel  53  and circumferentially spaced from one another (See  FIGS. 5-7 ). As will be discussed in greater detail below, the soft exterior material is injected into the aperture  28  where it flows through an interior of the hard core  18  and axially outwardly through the annular openings  32  and into the annular channel  53  to mechanically bond the soft exterior  20  to the hard core  18  to form the plunger assembly. 
     The hard core  18  has an elongate plunger rod  57  having three intersecting ribs  58  extending axially, upwardly from the first flange  52  in a direction opposite from the second flange  54  to define a generally three-pointed star shaped body  60  when viewed in horizontal cross-sectional dimension. A finger  61  extends from an upper surface  62  of each of the ribs  58 . The fingers  61  extend axially, upwardly and terminate in an enlarged distal end  66  having a hook shape extending radially inwardly. As shown in  FIG. 1 , the fingers grasp a stem of a poppet  68  of the valve with the plunger shown biased into a closed position by spring  70 . 
     Prior art fluid flow connectors  10 , like the one illustrated in  FIG. 3 , have utilized valves  14  which have included plungers  24  having O-rings  26 . The O-rings  26  in the prior art are fitted to the distal end of the plunger  24  as shown in  FIG. 4  and are made using EPDM. The O-rings  26  allow the valves  14  to have a fluid tight seal when the connectors  10  are in the closed position. One of the problems with the prior art valves  14  is that when the fluid flow connectors  10  are used to dispense diet soft drink syrup, the O-rings  26  have a tendency to swell significantly. In such applications, the prior art O-rings  26  swell to a point where there is no longer a fluid tight seal and the connectors begin to leak or let air in when they are not connected to the containers. The swollen O-rings  26  also decrease the flow rate of the syrup through the connectors  10  when the connectors are dispensing fluid from the containers. 
     The present invention is directed to a fluid flow connector  10  which does not involve the use of O-rings  26  but instead utilizes overmolding to mold a soft exterior  20  to plunger  16  as shown in  FIG. 2 . The soft exterior  20  replaces the O-ring  26 . Because it can be made of materials other than EPDM, the soft exterior  20  does not swell as significantly as the O-rings  26  when the connector  10  is used in diet soft drink application. Both the hard core  18  and the soft exterior  20  can be made of any suitable material depending on the applications in which the fluid flow connector  10  will be used. In one embodiment of the present invention, the hard core is made of a thermoplastic material while the soft exterior is made of a thermoplastic elastomer. 
     In one embodiment of the present invention, the hard core  18  of the plunger  16  is molded having holes or apertures  28  ( FIGS. 5-7 ) at the distal end  30  of the hard core  18 . When the soft exterior  20  is overmolded to the hard core  18 , the soft exterior  20  is shot or molded into the axially extending aperture  28  at the distal end  30  of the hard core  18  to fill the aperture  28  and to flow radially outward through annular openings  32  to form the soft exterior  20  so that the soft exterior  20  is mechanically attached to the hard core  18  of the plunger  16 . The distal end  30  of the plunger  18  and the soft exterior  20  is dimensioned to cooperatively engage and form a fluid tight seal with the fluid inlet  22  An example of a hard core  18  having aperture  28  and annular openings  32  at the distal end  30  is illustrated in  FIGS. 5-7 . 
     The soft exterior  20  can also be molecularly bonded to the hard core  18  of plunger  16 . In this method of the present invention, the hard core  18  is first molded and then the soft exterior  20  is overmolded within a reasonable time subsequent to the molding of the hard core  18 . In that way, the soft exterior  20  tends to molecularly bond to the underlying hard core  18  and form a single unit. The present invention also includes embodiments wherein the soft exterior  20  is both molecularly bonded and mechanically attached to the hard core  18 . 
     While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying Claims.