Patent Publication Number: US-11034487-B1

Title: Reservoir with stopper

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to, and the benefit of, U.S. Provisional Application No. 62/692,358 filed on Jun. 29, 2018 with the United States Patent Office, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     It is known to provide dispenser units within refrigerators, or other appliances, in order to enhance the accessibility to ice and/or water. Typically, such a dispenser unit will be formed in the freezer door of a side-by-side style refrigerator or in the fresh food or freezer door of a top mount style refrigerator. In either case or even in another location, a water line will be connected to the refrigerator in order to supply the needed water for the operation of the dispenser. For use in dispensing the water, it is common to provide a water tank within the fresh food compartment to act as a reservoir such that a certain quantity of the water can be chilled prior to being dispensed. 
     Certain dispenser equipped appliances available on the market today incorporate blow molded water tanks which are positioned in the fresh food compartments of the appliance, such as a refrigerator. More specifically, such a water tank is typically positioned in the back of the fresh food compartment, for example, behind a crisper bin or a meat keeper pan so as to be subjected to the cooling air circulating within the compartment. Since the tank is typically not an aesthetically appealing feature of the appliance, it is generally hidden from view by a sight enhancing cover. 
     For certain other dispenser equipped appliances, the reservoir may be molded, for example, by a process disclosed in U.S. Pat. No. 7,850,898, in which a heated extrudate is positioned in a mold followed by insertion of previously extruded profiles that are inserted into the beginning and end apertures of the main extrudate body. The mold is closed and pressure applied through the inserted profiles to expand the main extrudate body to fill the mold cavity, forming an essentially leak-proof seal between the extrudate body and the inserted profiles. 
     A molded reservoir requires significant set-up and manufacturing effort. What is needed is an improved reservoir and reservoir system that incorporate pre-manufacture or separately manufactured components using new and improved fittings or connections. 
     SUMMARY 
     The present disclosure described herein relates to a new reservoir and reservoir system for use in a water distribution system. What is disclosed herein is a reservoir useful in an appliance water dispensing system comprising one or more of the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments, being indicative of but a few of the various ways in which the principles of the present disclosure may be employed. 
     In one example, a reservoir for use in a water distribution system within an appliance comprises:
         a container having a vessel structure terminating at a neck around an opening;   a stopper inserted into and sealingly engaging the opening within the neck, the stopper comprising:
           an internal surface in communication with an interior of the container;   an external surface opposite the internal surface;   an inlet aperture and an outlet aperture through the stopper in fluid communication with the opening of the container;   
           an inlet tube in fluid communication with the inlet aperture; and   an outlet tube in fluid communication with the outlet aperture.       

     The reservoir may further include a cap engaging the stopper and the container at the neck. 
     The foregoing and other objects, features, and advantages of the examples will be apparent from the following more detailed descriptions of particular examples, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is made to the accompanying drawings in which particular examples and further benefits of the examples are illustrated as described in more detail in the description below, in which: 
         FIG. 1  is a partial perspective view of an appliance showing a diagrammatical cutaway view of a reservoir of the present disclosure. 
         FIG. 2  is a partial cross-sectional view of the reservoir shown in  FIG. 1  with the cross-section taken through section  2 - 2  of  FIG. 3 . 
         FIG. 3  is a perspective view of a stopper forming part of the reservoir of  FIG. 1 . 
         FIG. 4  is a perspective view of a stopper forming part of the reservoir of  FIG. 1 . 
         FIG. 5  is a side view of the stopper of  FIG. 4 . 
         FIG. 6  is yet another perspective view of a stopper forming part of the reservoir of  FIG. 1 . 
         FIG. 7  is a bottom view of a stopper forming part of the reservoir of  FIG. 1 . 
         FIG. 8  is an exploded perspective view of the reservoir of  FIG. 1  showing the container, stopper and cap separate from one another. 
         FIG. 9  is a perspective view of the reservoir of  FIG. 1  showing the stopper engaged with the container and the cap removed. 
         FIG. 10  is a perspective view of the reservoir of  FIG. 1  showing the container, stopper and cap assembled. 
         FIG. 11  is cross-sectional view of a reservoir for installation in an appliance in an inverted orientation. 
         FIG. 12  is a cross-sectional view of a reservoir for installation in an appliance in a horizontal or sideways orientation. 
     
    
    
     DETAILED DESCRIPTION 
     As used in this application, the term “overmold” means the process of injection molding a second polymer over a first polymer, wherein the first and second polymers may or may not be the same. An overmold having a specific geometry may be necessary to attach a tube to a fitting, valve, another tube, a diverter, a manifold, a fixture, a T connector, a Y connector or other plumbing or appliance connection. In one embodiment, the composition of the overmolded polymer will be such that it will be capable of at least some melt fusion with the composition of the polymeric tube. There are several means by which this may be affected. One of the simplest procedures is to insure that at least a component of the polymeric tube and that of the overmolded polymer is the same. Alternatively, it would be possible to ensure that at least a portion of the polymer composition of the polymeric tube and that of the overmolded polymer is sufficiently similar or compatible so as to permit the melt fusion or blending or alloying to occur at least in the interfacial region between the exterior of the polymeric tube and the interior region of the overmolded polymer. Another manner in which to state this would be to indicate that at least a portion of the polymer compositions of the polymeric tube and the overmolded polymer are miscible. In contrast, the chemical composition of the polymers may be relatively incompatible, thereby not resulting in a material-to-material bond after the injection overmolding process. 
     Referring now to  FIG. 1 , an appliance  10  having a water dispensing system is shown. A reservoir  100  of the present disclosure is illustrated within the appliance  10 . The reservoir  100  is a combination of separately manufactured components. The ability to combine separately manufactured components improves manufacturing availability, manufacturing lead-times, manufacturing set-up, and reduces manufacturing costs, to name a few advantages over prior reservoirs. Also, by separately manufacturing the components of the reservoir and utilizing the fittings of the present disclosure, the reservoir of the present disclosure provides different reservoir configurations or systems compatible with different appliances, while maintaining or reusing one or more manufacturing components, processes, or systems across the various configurations. 
     With reference to  FIG. 2 , the reservoir  100  of the present disclosure comprises a container  200 , a cap  300 , a stopper  400 , an inlet tube  500 , and an outlet tube  600 . Each of these components may be separately manufactured and combined as described in the present disclosure. Further, each of these components may be interchangeable with a variety of configurations of corresponding components, thereby, increasing efficiency in manufacturing systems by manufacturing one or more components which are interchangeable across a variety of different systems. Moreover, each of these components are modifiable by simply adding an additional manufacturing step to a prior manufacturing set-up or an existing manufacturing process, in lieu of redefining the entire manufacturing set-up for the entire component. By example, the container and the cap may be manufactured as a mated pair, independent of a separately manufactured stopper and/or the inlet and/or outlet tube. The cap may be manufactured to sealingly engage the container creating a leak proof enclosure, or vacuum, within the container. To form a reservoir, as presently disclosed, the container and the cap, which may be pre-manufactured as described above, are modified to accommodate a stopper and/or the inlet and/or outlet tubes. To this end, both the pre-manufactured container and cap are used for creating the reservoir, thereby, reducing waste and manufacturing expense in lieu of manufacturing a new or different container and cap. In one example, an aperture is formed in the cap to accommodate a stopper as disclosed herein. 
     As shown in  FIG. 2 , the reservoir  100  includes a container  200  having a vessel structure  210 . The vessel structure  210  terminates at a neck  220  around an opening  230 . A cap  300  sealingly engages the neck  220 . An interior cavity  310  of the cap encases an exterior perimeter  222 , or a section thereof, of the neck  220 . More specifically, an interior surface  312  of the interior cavity  310  of the cap  300  comprises threads  314  which engage and abut opposing threads  226  formed on the exterior perimeter  222  of the neck  220 . The threads allow the cap to advance on and off of the neck  220  and provide for a sealed engagement between the cap  300  and the neck  220 , as understood in the art for threaded fittings. Other methods for sealingly engaging the cap  300  to the neck  220  are contemplated herein, by example, a ratcheting connection, a friction connection, a barbed connection, a combination thereof, or the like. In some examples, the cap may be permanently attached to the neck of the vessel structure by permanent connections disclosed herein and understood in the art, examples of those being overmolding, adhesive, welding, a combination thereof, or the like. 
     An aperture  320  is formed in the cap  300  and extends from a top  330  of the cap into the interior cavity  310  of the cap as seen in  FIGS. 2 and 8 . The inlet and outlet tubes,  500 ,  600  extend through the aperture  320  of the cap  300  as shown in  FIG. 10 . The aperture may be formed into a pre-existing cap after manufacture of a cap. Alternatively, the aperture may be manufactured into the cap at the time of initial manufacture the cap. The cap  300  further comprises a top lip  340  adjacent the aperture  320  and positioned to the top  330  of the cap. In the example as illustrated by  FIG. 2 , the aperture  320  of the cap is smaller than the opening  230  and an external surface  420  of the stopper  400 . In one example as illustrated by  FIGS. 3-5 , the stopper  400  comprises a flange  410  positioned at the external surface  420  of the stopper. The flange may be integrally formed on the stopper. In some examples, the flange may be separate from the stopper and adjoining the exterior surface of the stopper, separate from the stopper and adhered to the exterior surface of the stopper, and/or an extension of the one or more surfaces of the stopper. Referring to  FIG. 2 , the aperture  320  of the cap may additionally be smaller than one or more sections of the flange, or the entire flange. In other words, the top lip  340  extending about the aperture of the cap engages the flange and secures the flange between the top lip  340  of the cap and a top edge  224  of the neck. In this example, the top lip  340  of the cap does not engage the neck  220  and is separated from the neck  220  by the flange  410 . Further, the stopper  400  is thereby secured within the opening  230  of the neck  220  by way of securing the flange  410  between the top lip  340  of the cap and the top edge  224  of the neck. The flange  410  may also be a seal or may be combined with a seal for forming a leak-proof connection between the cap, the neck, and/or the stopper. As illustrated by  FIGS. 3-5  the flange is a cylindrical flange that extends the entire circumference of the top of the neck  220 . Thus, a first seal is created as described above. Additionally, a second seal may be created between the stopper  400  and the neck  220  as discussed below. 
     As illustrated by  FIG. 2 , the stopper  400  is inserted into the opening  230  within the neck  220 . In these examples, the stopper  400  is separable from the cap  300  and/or the neck  220 . A leak-proof connection of the container  200  is formed at the opening  230  by way of engagement between the stopper  400  and the neck  220 . Such a leak-proof connection may occur, for example, as a result of friction, by use of seals (e.g. gaskets, o-rings, or the like), overmolding, adhesive, a combination thereof, etc. In the example illustrated by  FIGS. 3-5 , one or more recesses  470  are formed within the stopper  400 . The recesses  470  are formed at a perimeter  440  (also illustrated by  FIG. 2 ) of the stopper  400 , the perimeter engaging the neck  220  as illustrated by  FIG. 2 . A seal  480  may be positioned within each recess  470  for enhancing or forming a leak-proof connection between the stopper  400  and the neck  220 . In the example illustrated by  FIG. 2 , the seal  480  is an o-ring. A more robust seal between the stopper  400  and the neck  220  is created with two o-rings as shown in  FIG. 2 . Therefore, the reservoir  100  may include a first seal (as described in Par. [ 0024 ]) and a second seal (between the stopper  400  and the neck  220 ) as discussed above to form a leak-proof connection. 
     As illustrated by  FIGS. 3-5 , the stopper  400  further comprises an external surface  420  and an internal surface  430 . The internal surface  430  is in communication with an interior  210  of the vessel structure, as illustrated by  FIG. 2 . The external surface  420  is opposite the internal surface  430 . In the example illustrated by  FIGS. 3-5 , the perimeter  440  of the stopper  400  engaging the neck  220 , as illustrated by  FIG. 2 , is located between the internal surface  430  and the external surface  420  of the stopper. The stopper  400  includes an inlet tube support  455  and an outlet tube support  465 , which extend from flange  410  as shown in  FIGS. 4-5 . The inlet tube support  455  includes an inlet aperture  450  and the outlet tube support  465  includes an outlet aperture  460 . The inlet tube support  455  and the outlet tube support  465  may be molded as part of the stopper  400  or may be separate from the stopper  400 . The inlet tube support and the outlet tube support may be integrally formed with one another or be separate from one another. When the reservoir  100  is assembled, the inlet aperture  450  and the outlet aperture  460  are in fluid communication with the opening  230  of the container  200  as shown in  FIG. 2 . 
     An inlet tube  500  and an outlet tube  600  may respectively connect to the inlet tube support  455  and the outlet tube support  465 , and/or extend through the inlet aperture  450  and the outlet aperture  460 , respectively, of the stopper  400 . In one example, the stopper  400  is overmolded onto the inlet/outlet tubes at the inlet tube support  455  and the outlet tube support  465 . In other examples, the inlet tubes and the outlet tubes may be secured to the inlet tube support and the outlet tube respectively by other means known in the art, such as adhesive, welding, a combination thereof, or the like. The inlet and outlet tubes may be partially inserted into, extend from, or extend through the inlet tube support and the outlet tube support, respectively. In the example as illustrated by  FIG. 2 , ends of the inlet tube  500  and the outlet tube  600  extend through the inlet tube support  455  and the outlet tube support  465 , respectively. The inlet tube and/or the outlet tube, or sections of the inlet tube and/or outlet tube, may be flexible and/or comprise flexible tubing. 
       FIGS. 8-10  display the reservoir  100  from a disassembled configuration to an assembled configuration. Specifically,  FIG. 6  shows the container  200 , the stopper  400  (with inlet/outlet tubes  500 ,  600  connected) and the cap  300  all separate from each other.  FIG. 7  displays the stopper  400  (with inlet/outlet tubes  500 ,  600  connected) inserted within the neck  220  of the container  200 , but the cap  300  separate.  FIG. 10  illustrates the reservoir  100 , with the container  200 , the stopper  400  (with inlet/outlet  500 ,  600  tubes) and the cap  300  all assembled. 
     For certain applications, at least a portion of the inlet tube and/or the outlet tube may be integrally formed with the stopper. As an alternative to overmolding as described above, the inlet tube and/or the outlet tube may comprise a barb fitting, threaded fitting, or the like for engagement or connection with the stopper. Alternatively, the inlet tube and/or the outlet tube may be a tube fitting or connection integral to the stopper, a molded tubular portion, or an attached length of the tube. 
     As shown by  FIGS. 3 and 6-7 , the stopper  400  may further comprise a stopper cavity  490  that is open to the internal surface  430  of the stopper  400  and, thereby, the opening  230  of the container  200  (as illustrated by  FIG. 2 ). The stopper cavity  490  is separated from the external surface  420  by the perimeter  440  and/or the flange  410  of the stopper. In the example of  FIGS. 3 and 6-7 , the inlet aperture  450  and/or the inlet tube  500  opens into a first side  492  of the stopper cavity  490 . The first side  492  of the stopper cavity forms the shape of a crescent moon in the example  FIGS. 3 and 6-7 . However, any shape is contemplated herein. A second side  494  of the stopper cavity  490  forms an extension of the outlet aperture  460  and/or the outlet tube  600 . A cylindrical wall  495  extends downwardly into the stopper cavity  490  from a stopper cavity upper surface  493  to accommodate a dip tube  700  as described below. The cylindrical wall  495  may extend partially into the stopper cavity  490  or may extend fully into the stopper cavity  490  and terminate at internal surface  430 . In order to fill the reservoir to a desired level and subsequently dispense water in the upright vertical orientation shown in  FIG. 2 , the reservoir must vent air from the container  200  while the container fills with water to its desired level. The cylindrical wall  495  includes a fluid transfer opening  496 . The fluid transfer opening  496  provides fluid communication between the first side  492  and the second side  494  of the stopper cavity  490  when the dip tube  700  is inserted. The fluid transfer opening  496  is for the transfer of fluids, including gases and liquids, to assist in the appropriate flow of fluids through the reservoir. In the example as illustrated by  FIGS. 3 and 6-7 , the fluid transfer opening  496  extends in the axial direction of the outlet tube  600 . The fluid transfer opening  496  facilitates the venting of air. In particular, a dip tube  700  (as illustrated by  FIG. 2 ) may be frictionally inserted into the second side  494  of the stopper cavity  490 . However, the dip tube is only partially inserted into the second side  494  of the stopper cavity  490 . As a result, a section of the fluid transfer opening  496  remains open between the first side  492  and the second side  494  of the stopper cavity  490 . Therefore, a gap exists between the outlet tube  600  and the dip tube  700  (as illustrated by  FIG. 2 ), which allows air to be vented from the container  200  (as illustrated by  FIG. 2 ) through the fluid transfer opening  496  and out through the outlet tube  600 . Moreover, the fluid transfer opening  496  is adjustable in size, and may be adjusted by the distance or amount the dip tube  700  (as illustrated by  FIG. 2 ) extends into the second side  494  of the stopper cavity  400 . For example, the fluid transfer opening  496  will decrease in size the more the dip tube  700  (as illustrated by  FIG. 2 ) extends into the second side  494  of the stopper cavity  490 . Likewise, the fluid transfer opening  496  will increase in size the less the dip tube  700  (as illustrated by  FIG. 2 ) extends into the second side  494  of the stopper cavity  490 . Increasing or decreasing the size of the fluid transfer opening may be desirable to either increase or decrease the rate at which fluid is emptied from the reservoir. A tube stop  498  may be provided in the cylindrical wall  495  to locate an end of the dip tube  700  in forming the fluid transfer opening  496 , where the tube stop  498  prevents a fully-inserted dip tube  700  from contacting the stopper cavity upper surface  493  so the fluid transfer opening maintains fluid communication between the first side  492  and the second side  494  of the stopper cavity  490 . The fluid transfer opening  496  may comprise any type of opening or openings in the cylindrical wall  495 , such as holes, slots or other openings. 
     The dip tube  700  may be in fluid communication with either the inlet tube or the outlet tube, depending on the desired application. As illustrated by  FIG. 2 , the dip tube  700  is in fluid communication with the outlet tube  600  and/or the outlet aperture and extends into the opening  230  of the container  200  and the vessel structure  210 . The dip tube  700  may extend into the entire length of the vessel structure  210  or into a partial length of the vessel structure  210 . Like the inlet tube  500  and/or the outlet tube  600  extending from the vessel structure, the dip tube  700 , or sections of the dip tube, may be flexible and/or comprise flexible tubing. 
     For certain applications, air may flow out of the containers through the outlet tube without the addition of a fluid transfer opening as discussed below. Whether or not a fluid transfer opening is required is determined in part by the orientation of the reservoir in its installed position, whether a dip tube is provided on the inlet or the outlet, the position of the outlet aperture and/or the end of the outlet dip tube, and other factors. For example, in  FIG. 2 , the reservoir is oriented in an upright vertical position, and dip tube  700  is provided at the outlet aperture  460 . If no air vent were provided, the reservoir would stop filling at the depth of the end of the dip tube because the air in the container would be captured. 
     In an alternative embodiment, no fluid transfer opening or air vent would be needed if the orientation of the reservoir was inverted (i.e. if  FIG. 2  was upside down). In this example, the air would exit into the bottom of the dip tube  700  and out through the outlet tube  600 . Such an example is illustrated by  FIG. 11 , where the features of  FIG. 11  are illustrated as previously described with respect to  FIG. 2 . Still yet, in another example, as illustrated by  FIG. 12 , the vessel structure  210  is in a horizontal or sideways orientation. Likewise, the dip tube  700  may be arranged (e.g. bent) to facilitate air passage out through the outlet tube  600  without the use of an air vent. In one example, the dip tube  700  is an L-shaped dip tube, although the dip tube may be curved or arched. These examples illustrate the various orientations or configurations, or even a combination of configurations to facilitate positioning of the reservoir within an appliance. 
     The container  200  may be made of polyethylene terephthalate (PET), polycarbonate, aluminum, stainless steel or other suitable material. The container  200  may be formed from a multilayer material. A barrier film may be provided in at least one layer of the multilayer material, where the barrier layer inhibits passage of one or more from the group consisting of oxygen, carbon dioxide, water vapor, molecules affecting taste, molecules affecting odor. In one example, the container  200  and cap  300  are an off-the-shelf bottle and cap. The use of off-the-shelf existing bottle preforms and caps significantly reduces the tooling expense. Because existing threads that connect to the bottle are included in the off-the-shelf screw cap, it is not necessary to manufacture any threads as part of the stopper  400 . This makes the manufacturing process of the stopper easier, quicker and less expensive, where one example of manufacturing is overmolding. The present disclosure allows for the inlet and outlet tubes and the stopper  400  to be overmolded together in a single manufacturing operation. Additionally, because the stopper  400  is inserted into the opening of the neck  220  of the container or bottle  200 , seals or o-rings may be included with the stopper  400  to create a more robust seal between the stopper  400  and the container or bottle  200 . 
     In certain embodiments, the container  200  is a bottle, such as a bottle formed by injection blow molding. A bottle formed by injection blow molding may be useful in providing a strong material, such as PET, polycarbonate, or the like, at an efficient cost. In some examples, one or more of the stopper, the inlet tube, and the outlet tube are made from polymers known in the art including, but not limited to, polyethylene, polypropylene, PVC, polystyrene, nylon, polytetrafluoroethylene and thermoplastic polyurethanes. 
     In some examples, one or more of the stopper, the inlet tube, and the outlet tube are made from high density polyethylene which is crosslinked, although the process described herein can be used with tubes made from any crosslinked polymers. Such polymers may include, but are not limited to, nylon, EVA, PVC, metallocine, polypropylene, polyethylene, silicone, rubber and EPDM. Crosslinked polyethylene, also known as PEX, contains crosslinked bonds in the polymer structure changing the thermoplastic into a thermoset. Crosslinking may be accomplished during or after extrusion depending on the method of crosslinking. The required degree of crosslinking for crosslinking polyethylene tubing, according to ASTM Standard F 876, is between 65-89%. However, the present process contemplates that the tube may be partially crosslinked. In one example, the tube may only be crosslinked to 40%. There are three classifications of PEX, referred to as PEX-A, PEX-B, and PEX-C. PEX-A is made by peroxide (Engel) method. In the PEX-A method, peroxide blending with the polymer performs crosslinking above the crystal melting temperature. The polymer is typically kept at high temperature and pressure for long periods of time during the extrusion process. PEX-B is formed by the silane method, also referred to as the “moisture cure” method. In the PEX-B method, silane blended with the polymer induces crosslinking during secondary post-extrusion processes, producing crosslinks between a crosslinking agent. The process is accelerated with heat and moisture. The crosslinked bonds are formed through silanol condensation between two grafted vinyltrimethoxysilane units. PEX-C is produced by application of an electron beam using high energy electrons to split the carbon-hydrogen bonds and facilitate crosslinking. 
     Crosslinking imparts shape memory properties to polymers. Shape memory materials have the ability to return from a deformed state (e.g. temporary shape) to their original crosslinked shape (e.g. permanent shape), typically induced by an external stimulus or trigger, such as a temperature change. Alternatively or in addition to temperature, shape memory effects can be triggered by an electric field, magnetic field, light, or a change in pH, or even the passage of time. Shape memory polymers include thermoplastic and thermoset (covalently crosslinked) polymeric materials. 
     Shape memory materials are stimuli-responsive materials. They have the capability of changing their shape upon application of an external stimulus. A change in shape caused by a change in temperature is typically called a thermally induced shape memory effect. The procedure for using shape memory typically involves conventionally processing a polymer to receive its permanent shape, such as by molding the polymer in a desired shape and crosslinking the polymer defining its permanent crosslinked shape. Afterward, the polymer is deformed and the intended temporary shape is fixed. This process is often called programming. The programming process may consist of heating the sample, deforming, and cooling the sample, or drawing the sample at a low temperature. The permanent crosslinked shape is now stored while the sample shows the temporary shape. Heating the shape memory polymer above a transition temperature T trans  induces the shape memory effect providing internal forces urging the crosslinked polymer toward its permanent or crosslinked shape. Alternatively or in addition to the application of an external stimulus, it is possible to apply an internal stimulus (e.g., the passage of time) to achieve a similar, if not identical result. 
     A crosslinked polymer network may be formed by low doses of irradiation. Polyethylene chains are oriented upon the application of mechanical stress above the melting temperature of polyethylene crystallites, which can be in the range between 60° C. and 134° C. Materials that are most often used for the production of shape memory linear polymers by ionizing radiation include high density polyethylene, low density polyethylene and copolymers of polyethylene and poly(vinyl acetate). After shaping, for example, by extrusion or compression molding, the polymer is covalently crosslinked by means of ionizing radiation, for example, by highly accelerated electrons. The energy and dose of the radiation are adjusted to the geometry of the sample to reach a sufficiently high degree of crosslinking, and hence sufficient fixation of the permanent shape. 
     Another example of chemical crosslinking includes heating poly(vinyl chloride) under a vacuum resulting in the elimination of hydrogen chloride in a thermal dehydrocholorination reaction. The material can be subsequently crosslinked in an HCl atmosphere. The polymer network obtained shows a shape memory effect. Yet another example is crosslinked poly[ethylene-co-(vinyl acetate)] produced by treating the radical initiator dicumyl peroxide with linear poly[ethylene-co-(vinyl acetate)] in a thermally induced crosslinking process. Materials with different degrees of crosslinking are obtained depending on the initiator concentration, the crosslinking temperature and the curing time. Covalently crosslinked copolymers made form stearyl acrylate, methacrylate, and N,N′-methylenebisacrylamide as a crosslinker. 
     Additionally shape memory polymers include polyurethanes, polyurethanes with ionic or mesogenic components, block copolymers consisting of polyethyleneterephthalate and polyethyleneoxide, block copolymers containing polystyrene and poly(1,4-butadiene), and an ABA triblock copolymer made from polly(2-methyl-2-oxazoline) and a poly(tetrahydrofuran). Further examples include block copolymers made of polyethylene terephthalate and polyethylene oxide, block copolymers made of polystyrene and poly(1,4-butadiene) as well as ABA triblock copolymers made from poly(tetrahydrofuran) and poly(2-methyl-2-oxazoline). Other thermoplastic polymers which exhibit shape memory characteristics include polynorbornene, and polyethylene grated with nylon-6 that has been produced for example, in a reactive blending process of polyethylene with nylon-6 by adding maleic anhydride and dicumyl peroxide. 
     The stopper  400  may be sealed to the container  200  in a fluid-tight or leak-free seal using shape memory properties of a selected polymer as discussed above. The stopper  400  may be formed to a desired size, having the stopper perimeter  440  larger than a corresponding inside dimension of the neck  220  of the container  200 , and then crosslinked. Crosslinking of the stopper  400  sets a permanent stopper size larger than the desired inside dimension of the neck of the container. Then, installing the stopper into the opening  230  of the container  200  requires contracting the stopper perimeter  440  to fit into the neck of the container, installing the cap onto the neck, and then applying an external stimulus, such as temperature, or an internal stimulus, such as by the passage of time, for the shape memory of the polymer to tend toward its permanent shape. The expansion of the stopper perimeter within the neck of the container may be used to form a fluid-tight, leak-proof or leak-free seal, in addition to or in lieu of a seal or seals  480  as previously discussed, such as an o-ring or gasket. 
     The opening  230  of the container  200  is circular for typical applications, however, it is contemplated that the opening and neck around the opening may be any shape as desired. The neck and opening may have a diameter or dimension smaller than the corresponding dimension across the vessel structure of the container. Alternatively, the neck and opening may have a diameter or dimension about the same as the corresponding dimension across the vessel portion of the container. 
     The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular form of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The terms “at least one” and “one or more” are used interchangeably. The term “single” shall be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” are used when a specific number of things are intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (i.e., not required) feature of the embodiments. 
     While the present disclosure has been described with reference to examples thereof, it shall be understood that such description is by way of illustration only and should not be construed as limiting the scope of the claimed examples. Accordingly, the scope and content of the examples are to be defined only by the terms of the following claims. Furthermore, it is understood that the features of any example discussed herein may be combined with one or more features of any one or more examples otherwise discussed or contemplated herein unless otherwise stated.