Abstract:
A valve assembly for use with a self-sealing collapsible storage bag, the valve assembly having a first portion comprising a housing that has a sealing surface and contains a valve mechanism. A second portion has a sealing surface that is configured to mate with the sealing surface of the first portion. A snap mechanism is configured to allow the first and second portions to be snapped together with their respective sealing surfaces facing each other to form a substantially airtight seal. In operation, the first and second portions are positioned on opposing sides of a panel of a plastic storage bag, and snapped together so as to sandwich the panel between the first and second portions of the valve assembly. The plastic bag is pierced in the area of the valve assembly either during installation of the valve assembly, or later by insertion of a nozzle. Gas or fluid such as air may be selectively removed from or added to the interior of the storage bag through the valve mechanism.

Description:
RELATED APPLICATIONS 
     The present invention claims the benefit of U.S. Provisional Application Ser. No. 60/481,887 filed on Jan. 13, 2004, the specification of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to disposable, flexible, self-sealing storage bags and, more particularly, to an valve feature for disposable, self-sealing storage bags that can be installed and removed by an end user that facilitates the convenient evacuation of air and/or pressurization of the storage bag as well as maintaining an airtight seal to prevent gasses from leaving or entering the storage bag. 
     RELEVANT BACKGROUND 
     Self-sealing, disposable, plastic storage bags are flexible, disposable plastic bags commonly used to temporarily store food, such as leftovers or sandwiches, or to place food, such as meats, in the freezer over a long period of time. These storage bags incorporate interlocking strips which extend across an open end of the bag. The interlocking strips include mateable male and female, or tongue and groove portions which interlock to close the open end of the bag. Examples include storage bags sold under the trademark ZIPLOC®, which is a registered trademark of SC Johnson &amp; Son, Inc. and GLAD®, which is a registered trademark of the Glad Products Company. Self-sealing storage bags are primarily purchased in the consumer market for storing perishable foods. 
     Once contents are placed in the storage bag, the male and female strips are oriented, engaged, and pressed shut by applying pressure across the strips with the fingers or a slide mechanism. Conventional self-sealing bags, however, are not designed for conveniently evacuating air from the bag or for maintaining an airtight seal. Hence, food can still go stale or suffer freezer burn as a result of trapped air within the bag. This is because conventional self-sealing storage bags do not offer structure for evacuating air. 
     To evacuate air from inside the bag, users try to keep a segment of the bag open while pressing down on the bag to force air out. This process fails to remove all the air and is a crude, inconvenient way to evacuate air. Other users may attempt to use their mouth to suck air from the storage bag. This process also unable to remove all air, and risks contamination of the bag&#39;s contents with germs. 
     A significant problem associated with providing an airtight, self-sealing bag that evacuates air relates to manufacturing. Plastic storage bags are extruded and formed at a high speed which reduces production costs so that the storage bags can be marketed at a price point that is acceptable to consumers. High speed manufacturing processes make it difficult to alter the structure of the bag without affecting production and therefore increasing cost significantly. Existing processes and techniques for installing valve assemblies, for example, increase the cost of a storage bag to the point that it is no longer practical for disposable applications in which storage bags are commonly employed. 
     U.S. Pat. No. 5,240,112, issued to Neuberger, shows a storage bag with a stem with a pinched valve protruding outward from the lower end. U.S. Pat. No. 5,544,752, issued to Cox, shows storage bag that includes a permanent, exterior suction conduit that is designed to break off after use. U.S. Pat. No. 3,980,226, issued to Franz, comprises a storage bag having a permanently affixed evacuating tube with a threaded cap and an open end which is tied shut. U.S. Pat. No. 6,045,264 shows a system that attempts to improve on several of the deficiencies of earlier systems, but still requires that the bag itself be formed as a special-purpose evacuable bag. These systems are not compatible with existing extrusion manufacturing techniques. 
     Some of the more effective food storage systems use a “rolled bag” technique in which the user purchases a roll of material that is essentially a plastic channel, then forms bags by heat sealing two ends of the channel. These systems are often referred to as “seal-a-meal” systems as exemplified in U.S. Pat. No. 4,021,290. Variations of this system have been introduced that provide various mechanisms for removing air from the bag before sealing. These systems tend to be more expensive than disposable storage bags, and they are more difficult to use because the user is actually forming each bag one at a time. 
     A need exists for a food storage system that is both cost effective and allows users to evacuate air from commercially available self-sealing plastic storage bags. 
     SUMMARY OF THE INVENTION 
     The present invention solves the need by providing a valve assembly that can be installed by a user as needed to convert a conventional self-sealing storage bag into a storage bag that can be vacuum sealed. In a specific embodiment, a two-piece snap fit valve assembly is provided that a user can install on any plastic storage bag. Once installed, the valve assembly may be coupled to a vacuum source so that air can be conveniently removed from the storage bag as required by the user. Alternatively, the valve may be used to pressurize the storage bag so as to cushion and protect the contents. 
     By providing a user-installable valve assembly the storage bag itself can be manufactured using efficient, low-cost processing techniques available to any storage bag manufacturer, while at the same time giving the user the benefit of being able to convert conventional storage bags into vacuum seal storage bags as needed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a front view of bag having valve assembly in accordance with invention. 
         FIG. 2  shows a cutaway view taken along cut line shown in  FIG. 1 . 
         FIG. 3  shows a cutaway view showing air evacuation using a sports ball type valve for the internal of the air valve. 
         FIG. 4  illustrates a cross-section of an alternative valve and snap ring in accordance with the present invention. 
         FIG. 5  shows a perspective view of the valve assembly of  FIG. 2  to illustrate the snap together features of a particular embodiment of the present invention. 
         FIG. 6  storage system in accordance with the present invention including a bag with a valve assembly attached to a vacuum source. 
         FIG. 7  and  FIG. 8  show an exploded view of an alternative embodiment valve assembly in accordance with the present invention. 
         FIG. 9  shows a vacuum source in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention involves improved plastic bag-based storage systems in which a conventional self-sealing storage bag is converted on-demand into an evacuable storage bag. A user-installable valve assembly, conveniently provided as a two-piece, snap together assembly, is installed on any conventional self-sealing plastic storage bag. The user can select the size, brand, quality, and other characteristics from the wide variety of available plastic storage bag options. The present invention also involves a system which includes the valve assembly, self-sealing storage bags and a vacuum source which can be readily attached to evacuate air from storage bags once the valve is installed. While the present invention has significant applicability in food storage, and in particular home food storage, the invention may be used to store other materials to protect them from exposure to air. For example, the present invention is readily employed to store biomedical products and waste, collectibles, valuable papers, digital media, and the like. 
       FIG. 1  illustrates a front view of a storage system including a sealable storage bag  100 . Bag  100  includes front sheet  102  and rear sheet  104  (partially hidden behind the front sheet) that are sealed at edges  112 ,  114  and  116  to define a pouch  101 . Edges  112 ,  114  and  116  may be sealed by any convenient means such as heat sealing, ultrasonic welding, or the like, which results in a substantially air tight seal as is common in commercially available storage bags. An open end  108  allows items to be placed within pouch  101 . Sealing mechanisms  110  provide a substantially air tight seal when closed. Typical storage bags use a tongue strip on one sheet (e.g., sheet  102 ) and a complementary groove strip on the opposite sheet (e.g., sheet  104 ). Although tongue-in-groove sealing mechanisms are common, the present invention is operable with any sealing mechanism  110  including adhesive, clips, heat seal, and the like. 
     Valve assembly  106  described below is mounted in either the front sheet  102  or back sheet  104  so that a substantially airtight seal is achieved between assembly  106  and sheet  102 . By “substantially airtight” it is meant that the seal will inhibit airflow into or out of pouch  101  for a time desired by the user in a particular application. A reasonable amount of time might be a few hours in some applications, up to months or years in other applications. 
     Bag  100  includes opening  108  between sheet  102  and  104 . Reusable/re-closable or zipper type airtight seal  110  is positioned so that it may be opened to receive product e.g., food or other material. The air valve assembly  106  can be installed and seal  110  is closed to form an airtight seal to the bag  100 . The bag  100  with reusable seal  110  may be any of several brands including “Ziploc”, “Glad”, “Hefty”, or others. Moreover, many different varieties of bags are available in which the plastic thickness, closure mechanism, plastic type, or other characteristics are modified to enhance performance in particular applications. For example, the present invention is applicable to freezer bags, standard bags, multilayer bags designed to improve freshness, and the like. 
     Pouch  101  defines an inner volume for placing items such as food, valuables, waste materials, and the like. The present invention enables air or other fluid to be removed from or added to the inner volume after the seal  110  is closed. In this way, air that causes food spoilage can be removed from pouch  101  after it is sealed and/or protective gasses/fluids can be added to pouch  101  after it is sealed. 
       FIG. 2  is a cutaway view of the valve assembly along the cut line  2 - 2 ′ shown in  FIG. 1 . Valve assembly  106  includes an outer portion  204  and snap ring  210 . Outer portion  204  and snap ring  210  are two separate components made of, for example, a food grade plastic material. Valve assembly  106  is assembled by placing snap ring  210  inside of bag  100  and putting outer portion  204  on the outside surface of sheet  102  (or sheet  104 ) then pressing the outer portion  204  into the snap ring  210  to form an airtight connection. 
     Outer portion  204  includes a valve mechanism  202  which airflow into or out of bag  100 . Valve mechanism  202  may be a one-way or check valve, or a two-way valve. Valve mechanism may be self-sealing or manually operated. In a particular embodiment, valve element  202  comprises an air valve similar to that used for inflating a sports ball. For example, pressurized elastomer can be placed within a cavity defined by cup  203 . A tiny hole  206  may be formed through the elastomer to allow a needle to be removeably placed through the valve element  202  when it is desired to and/remove air or fluid from bag  100 . 
     As shown in  FIG. 2 , as snap ring  210  is installed, the plastic sheet  102  conforms to the contours of outer portion  204  and stretches tight across the bottom of valve mechanism  202 . This enables the bag  102  to be pierced cleanly as shown in  FIG. 3 . In a particular embodiment, outer portion  204  is fitted with a snap protrusion  205  that is spaced downward from the bottom surface of outer portion  205  sufficiently to allow snap ring  210  to seat firmly against outer portion  204  when installed, as shown in  FIG. 3 . 
     When installed, as shown in  FIG. 3 , sheet  102  is sandwiched between snap ring  210  and outer portion  204  with sufficient force to provide the desired airtight seal. Sheet  102  is deformed to conform about the contours of outer portion  204 . Needle  400  is pressed through opening  206  to pierce sheet  102  and create a temporary opening that enables air or other fluids to be removed from or added to the interior volume of bag  100 . Optionally, a needle stop  401  may be used to limit the penetration of needle  400  into the inner volume of bag  101 . Once removed, valve mechanism  202  prevents further air flow. For example, if a pressurized elastomer is used to implement valve mechanism  202 , the elastomer closes up opening  206  to create a substantially airtight seal. 
       FIG. 4  illustrates an alternative embodiment in which sealing surfaces of upper portion  404  and inner ring  410  are textured to improve sealing. In the particular example, a number of corrugations are placed on the surface to provide a superior seal. The corrugations may be quite small or relatively large as illustrated in  FIG. 4 . There may be as few as one corrugation up to tens or more if the corrugations are smaller. O-rings or similar sealing mechanisms may be used to improve the seal as well. Also, the sealing surfaces that contact sheet  102  may be coated with an adhesive, gel-type or putty-type sealing enhancer, vacuum oil, or the like (not visible) when desired to improve sealing performance. 
       FIG. 5  shows a perspective view of the valve assembly of  FIG. 2  to illustrate the snap together features of a particular embodiment of the present invention. Snap protrusions  205  are placed at two or more locations around the circumference of outer portion  204 . Snap protrusion  205  may be substantially continuous as well, although this could make installation somewhat more difficult as it would require more pressure to force the snap ring  210  over the snap protrusion  205 . In some embodiments, snap protrusion  205  may have a hinge-like attachment to outer portion  204  in that it is attached at only one edge (e.g., its lower edge). This arrangement allows the snap protrusion  205  to move inward to allow snap ring  210  to be forced over, then snap back outward once snap ring  210  has cleared the upper portion of snap protrusion  205 . A wide variety of snap type frictional attachment means are known and may be substituted for the particular implementation shown herein. 
       FIG. 6  is a schematic view illustrating the storage system in accordance with the present invention including a storage bag and user-installable valve mechanism in accordance with the present invention. In operation, a vacuum source  500  is coupled to nozzle  400  by tubing  501 , which is in turn coupled to the inner volume of bag  100  via the valve mechanism in accordance with the present invention. Vacuum source  500  is sized and powered to be capable of drawing the desired vacuum, which need not be particularly strong. Vacuum source  500  may be implemented by a hand operated pump, or an electric pump that is either batter powered or coupled to main power in the kitchen or work area (e.g. Fresh Savers Plus hand-held vacuum pump or some other compact vacuum pump). 
       FIG. 5  shows the item  504 , such as a food product or other material, is placed in the bag  100  and the re-sealable/re-closable seal has been closed. The vacuum then withdraws air by creating a vacuum inside the bag  100 . Food is left free of moisture and air preserving the food or product in bag  100 . Alternatively, vacuum device  500  may be replaced by a pressurized gas or fluid source. For example, is it increasingly common to purchase canisters of helium, argon, nitrogen or other neutral gas to preserve wine and prevent oxygen exposure to open bottles of wine. These same canisters could be used to pressurize the inner volume of bag  100  with a neutral atmosphere. 
       FIG. 7  shows an exploded view of an alternative embodiment valve assembly in accordance with the present invention. The implementation of  FIG. 7  provides a needle-less vacuum coupling which has some advantages when storing materials such as food, hazardous waste, medical materials and the like. In  FIG. 7  an outer portion  702  of the assembly is formed as multiple components that are assembled together by welding, gluing or other suitable assembly method that allows closure mechanism  708  to move along the axis illustrated by a dashed line within a cavity formed by a cap  704  and a keeper  714 . In a particular embodiment a spring (not visible) is placed inside keeper  714  so as to engage a closure mechanism  708  and push it into sealable contact with surfaces of cap  704 . The closure mechanism  708  may comprise, for example, a plunger, ball valve, duckbill valve, umbrella valve, or other available mechanism the meets the needs of a particular application. In an embodiment of the invention a duckbill valve may be used within the cavity formed by cap  704  and keeper  714  to provide a vacuum/pressure seal. 
     The valve assembly shown in  FIG. 7  is assembled into an outer piece  702  and an inner piece or base  710 . Base  710  is placed inside a collapsible bag (not shown in  FIG. 7 ) and outer piece  702  is pressed into base  710  from the outside of the bag. Cap  704  is provided with a piercing point having air passages  706  formed therein so as to pierce a hole in the bag sidewall during installation. The tight fitment (e.g., frictional fit, snap fit, or the like) between outer piece  702  and base  710  creates a substantially air-tight seal where the valve assembly is installed. 
     In operation, a vacuum source  500 , such as shown in  FIG. 9 , is coupled to keeper  714 . Vacuum source  500  creates a negative pressure that will urge the closure mechanism  708  away from sealing surfaces of component  714  and compress the spring within keeper  714 . The action of closure mechanism  708  opens a passageway for gasses to flow through from pass through passages  716  and  706  and out of the bag through the now-open valve assembly. When the vacuum source is release the spring automatically closes the valve by forcing closure mechanism  708  into sealable contact with cap  704 . Base  710  may be formed with a number of fins that inhibit the bag sidewalls from collapsing and blocking air passage  716 / 706 . 
       FIG. 8  shows the valve assembly of  FIG. 7  in an assembled state. In  FIG. 8  a bag is not shown to ease illustration and understanding. In practice, a bag sidewall would be located where the lowest portion of out piece  702  meets with the uppermost portion of base  710 . Once assembled as shown in  FIG. 8  the present invention provides a compact, user installable system for removing air from a collapsible storage bag. 
       FIG. 9  shows a hand-operable vacuum source  500  in accordance with an embodiment of the present invention. The particular example in  FIG. 9  is similar to a bicycle pump having a pump body  901  that, together with pump end cap  905 , defines a cylindrical compression chamber. A piston (not visible) inside chamber  901  is coupled to handle  907  by a piston rod  909 . Vacuum source  500  is operated by pumping handle  907  up and down in a manner akin to a bicycle pump. A negative pressure is created and coupled by tubing  903  to a coupling boot  911 . Coupling boot  911  is sized to mate with the upper portion of valve assembly  702  during operation. 
     A useful feature of the vacuum source  500  shown in  FIG. 9  is the use of a detachable end cap  905  that allows the compression chamber to be opened for cleaning. In applications that involve storage of liquid or semi-liquid materials inside a storage bag such as food storage, storage of medical materials and the like, there is a possibility that some of the stored material will be pulled through the valve assembly during evacuation. By removing end cap  905  a user can easily clean the inside of the compression chamber and the piston mechanisms therein, as well as have access to tubing  903  so that it can be thoroughly cleaned. 
     The present invention is applicable in any industry in which storage of a product such that the product is isolated from surrounding gasses is involved. Exemplary use cases include food storage, containment of biomedical materials, containment of hazardous waste, preservation of biological samples, preservation of collectibles and valuables to prevent tarnish, storage of optical devices such as lenses, telescopes, microscopes, binoculars and the like. 
     Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter claimed.