Abstract:
A one-way valve allows air to be drawn from a collapsible, flexible, airtight bag using a vacuum source. When the vacuum source is removed, the one-way valve prevents air from reentering the bag. The valve assembly comprises: a valve base comprising an opening, a seat disposed along a periphery of the opening, a flange surrounding the seat, and first and second pivot supports; a flapper comprising a diaphragm that is deformable and overlies the opening; and a cap pivotably supported by the first and second pivot supports for pivoting between first and second angular positions, the cap comprising at least one vent hole. The cap maintains the diaphragm in contact with the seat along an entire perimeter of the seat when the cap is in the first angular position and does not maintain the diaphragm in contact with the seat along its entire perimeter when the cap is in the second angular position.

Description:
RELATED PATENT APPLICATION 
       [0001]    This application claims the benefit, under Title 35, United States Code, §119(e), of U.S. Provisional Application No. 60/966,061 filed on Aug. 24, 2007. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention generally relates to evacuable storage containers, and in particular, to evacuable reclosable storage bags. 
         [0003]    Collapsible, evacuable storage containers typically include a flexible, airtight bag, an opening through which an article is inserted inside the bag, and a fixture through which excess air is evacuated. A user places an article into the bag through the opening, seals the opening, and then evacuates the air in the bag through the fixture. With the bag thus evacuated, a compressible article contained therein may be significantly compressed so that it is easier to transport and requires substantially less storage space. 
         [0004]    Collapsible, evacuable storage containers are beneficial for reasons in addition to those associated with compression of the stored article. For example, removal of the air from the storage container inhibits the growth of destructive organisms, such as moths, silverfish, and bacteria, which require oxygen to survive and propagate. Moreover, such containers, being impervious to moisture, inhibit the growth of mildew. 
         [0005]    Not only large, compressible items such as clothing may be stored in a collapsible, evacuable storage container. For example, it may be desirable to store bulk items made of small particles, such as powders or granulated resins, in an evacuated container. One situation that commonly occurs is that a particular bulk item is shipped in a large, rigid container such as a drum. Bulk items may be moisture sensitive and are sealed against moisture during shipment. But many times a user does not need to use the entire contents of the large container, and so once exposed to the moisture in the air the remaining bulk contents quickly become unusable and are thus wasted. 
         [0006]    One collapsible, reusable, evacuable storage container is shown in U.S. Pat. No. 5,480,030. This patent discloses a one-way air valve assembly having a flexible diaphragm that seals against a valve seat. The valve assembly also has vanes positioned to prevent the bag material or bag contents from obstructing air holes or the diaphragm while air is being evacuated through the valve assembly. 
         [0007]    There is a continuing need for improvements in the valve assembly of such evacuable storage containers. For example, improvements in the valve assembly structure that enhance the sealing function are desired in order to ensure that the storage container will be leakproof when evacuated. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    The invention is directed to improvements in the valve assembly of a collapsible, evacuable storage container. Such storage containers have a one-way valve assembly that allows air to be drawn from a collapsible, flexible, airtight bag using a vacuum source. When the vacuum source is removed, the one-way valve prevents air from re-entering the bag. 
         [0009]    One aspect of the invention is a valve assembly comprising: a valve base comprising an opening, a seat disposed along a periphery of the opening, a flange surrounding the seat, and first and second pivot supports; a flapper comprising a diaphragm that is deformable and overlies the opening; and a cap pivotably supported by the first and second pivot supports for pivoting between first and second angular positions, the cap comprising at least one vent hole, wherein the cap maintains the diaphragm in contact with the seat along an entire perimeter of the seat when the cap is in the first angular position and does not maintain the diaphragm in contact with the seat along its entire perimeter when the cap is in the second angular position, the opening being closed by the diaphragm when the cap is in the first angular position, and the diaphragm being free to deform so that a portion thereof is not in contact with the seat when the cap is in the second angular position. 
         [0010]    Another aspect of the invention is a bag comprising: a receptacle having a mouth at an upper end and comprising a wall having an aperture; a plastic zipper joined to the mouth, wherein the zipper comprises first and second zipper strips that extend across the mouth, the first zipper strip comprising a first closure profile and the second zipper strip comprising a second closure profile, the first and second closure profiles being mutually interlockable to form a hermetic seal, the mouth being closed when the first and second closure profiles are interlocked and being open when the first and second closure profiles are disengaged; and a one-way valve assembly installed in the aperture in the wall of the receptacle and comprising: a valve base comprising an opening, a seat disposed along a periphery of the opening, a flange surrounding the seat and joined to the wall of the receptacle, and first and second pivot supports; a flapper comprising a diaphragm that is deformable and overlies the opening; and a cap pivotably supported by the first and second pivot supports for pivoting between first and second angular positions, the cap comprising at least one vent hole, wherein the cap maintains the diaphragm in contact with the seat along an entire perimeter of the seat when the cap is in the first angular position and does not maintain the diaphragm in contact with the seat along its entire perimeter when the cap is in the second angular position, the opening being closed by the diaphragm when the cap is in the first angular position, and the diaphragm being free to deform so that a portion thereof is not in contact with the seat when the cap is in the second angular position. 
         [0011]    A further aspect of the invention is a bag comprising: a receptacle having a mouth at an upper end and comprising a wall having an aperture; a resealable hermetic sealing device joined to the mouth; and a one-way valve assembly installed in the aperture in the wall of the receptacle and comprising: a valve base comprising an opening, a seat disposed along a periphery of the opening, a flange surrounding the seat and joined to the wall of the receptacle, and first and second pivot supports; a flapper comprising a diaphragm that is deformable and overlies the opening; and a cap pivotably supported by the first and second pivot supports for pivoting between first and second angular positions, the cap comprising at least one vent hole, wherein the cap maintains the diaphragm in contact with the seat along an entire perimeter of the seat when the cap is in the first angular position and does not maintain the diaphragm in contact with the seat along its entire perimeter when the cap is in the second angular position, the opening being closed by the diaphragm when the cap is in the first angular position, and the diaphragm being free to deform so that a portion thereof is not in contact with the seat when the cap is in the second angular position. 
         [0012]    Other aspects of the invention are disclosed and claimed below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a drawing showing an isometric view of one conventional type of collapsible, evacuable storage bag. 
           [0014]      FIG. 2  is a drawing showing an isometric view, from above, of a valve assembly with press-to-open cap suitable for use with a bag of the type depicted in  FIG. 1 . 
           [0015]      FIG. 3  is a drawing showing an isometric view, from above, of the valve assembly depicted in  FIG. 2 , but with the press-to-open cap removed to reveal a flapper element. 
           [0016]      FIG. 4  is a drawing showing an isometric view, from above, of the valve assembly depicted in  FIG. 2 , but with the press-to-open cap in the open position for extracting air from the storage bag (not shown) via a vacuum source (not shown). 
           [0017]      FIG. 5  is a drawing showing a cross-sectional view of the valve assembly depicted in  FIG. 4 , i.e., with the cap in its open position. The section is taken along a plane normal to the cap&#39;s pivot axis. 
           [0018]      FIG. 6  is a drawing showing an isometric view, from below, of a ribbed valve base of the valve assembly depicted in  FIG. 2 . 
           [0019]      FIG. 7  is a drawing showing a cross-sectional view of the valve assembly depicted in  FIG. 2 , i.e., with the cap in its closed position. The section is taken along a plane normal to the cap&#39;s pivot axis. 
           [0020]      FIGS. 8 and 9  are drawings showing cross-sectional views of alternative embodiments of the valve assembly depicted in  FIG. 2 . In each of  FIGS. 8 and 9 , the section is taken along a plane parallel to the cap&#39;s pivot axis and the cap is shown in its closed position. 
           [0021]      FIG. 10  is a drawing showing an isometric view, from above, of a valve assembly with press-to-open cap of alternative design. 
       
    
    
       [0022]    Reference will now be made to the drawings in which similar elements in different drawings bear the same reference numerals. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0023]      FIG. 1  shows a conventional collapsible, evacuable storage container  2  comprising a bag  4 , a valve assembly  6 , and a zipper  8  comprising a pair of mutually interlockable extruded zipper strips that are joined to each other at opposing ends thereof. Although not shown in  FIG. 1 , the conventional valve assembly  6  also typically comprises a cap that can be snapped onto a portion of the valve assembly that is disposed on the exterior of the bag  4 . The cap must be removed before the bag can be evacuated, and then is replaced after the bag has been evacuated. The cap is intended to supplement the air pressure on the diaphragm and help to seal the valve assembly to prevent air from entering the evacuated bag. 
         [0024]    The bag  4  typically comprises front and rear walls or panels (made of thermoplastic material) that are joined together at the bottom and two sides by conduction heat sealing to form a receptacle having an interior volume and a mouth in which the zipper  8  is installed. One wall of bag  4  has a hole (not shown in  FIG. 1 ) in which to install the valve assembly  6 . The bag may be constructed of a blended extrusion layer of polyethylene sandwiched between a nylon layer and a layer of polyethylene sheeting. However, the materials comprising the bag may be altered so as to prevent interaction with the bag contents. 
         [0025]    During use, one or more discrete articles or a bulk material (not shown) may be placed inside the bag  4  while the zipper  8  is open, i.e., while the closure profiles of the interlockable zipper strips are disengaged from each other. After the article or material to be stored has been placed inside the bag, the mouth of the bag  4  can be sealed by pressing the zipper strips together to cause their respective closure profiles to interlock with each other. Although the zipper closure profiles may have many different designs, the design must be one that ensures that an airtight seal can be formed at the mouth of the bag. 
         [0026]    With the zipper  8  closed, the interior volume of the bag or receptacle  4  is hermetically sealed. The interior volume can now be evacuated by sucking air out of the bag via the one-way valve assembly  6 . Air can be drawn out of bag  4  through valve assembly  6  using a conventional vacuum source, such as a household or industrial vacuum cleaner. The valve assembly  6  and the zipper  8  maintain the vacuum inside bag  4  after the vacuum source is removed. 
         [0027]    A valve assembly  10  in accordance with one embodiment of the present invention will now be described with reference to  FIGS. 2-8 . This valve assembly  10  can be substituted for the prior art valve assembly  6  in storage bags of the type depicted in  FIG. 1 . 
         [0028]      FIGS. 2 and 4  are isometric views, from above, showing a valve assembly  10 , in closed and open states respectively, in accordance with one embodiment. The valve assembly  10  comprises a valve base  12  and a press-to-open, press-to-close cap  14  pivotably mounted to the valve base  12 . The cap  14  is provided with a plurality of vent holes  18  which allow air to flow through the cap  14  during bag evacuation. In particular, when the valve is open, i.e., when cap  14  is in its open position as seen in  FIG. 4 , air can be sucked out of a storage bag via vent holes  18  using devices such as common household vacuum cleaner. Both the valve base  12  and the cap  14  are preferably made of injection-molded thermoplastic material. 
         [0029]    The cap  14  is shown in its closed position in  FIG. 2  and in its open position in  FIG. 4 . Portion  16  of cap  14  bears the legend “PRESS” and indicates the area where a user should apply pressure with a digit or utensil in order to open the valve by causing the cap  14  to pivot about an axis from its closed position (seen in  FIGS. 2 and 7 ) to its open position (seen in  FIGS. 4 and 5 ). 
         [0030]      FIG. 3  shows the valve assembly  10  with the cap removed to reveal a flapper or valve element  28 , which is also a component of the valve assembly  10 . The flapper  28  comprises a diaphragm  32  connected to a base portion  34  by means of a necked portion  36 . In a known embodiment, the flapper  28  is made of clear polyvinylchloride (PVC). 
         [0031]    As also shown in  FIG. 3 , the valve base  12  has an opening  26  that is covered by the diaphragm  32  of the flapper  28 . In the valve closed state, the diaphragm  32  sits on a pair of concentric annular beads  42  and  44  that project upward from the valve base  12  and encircle opening  26 . The position of the flapper  28  is dictated by a pair of flapper positioning posts  38  and a pair of retainer tabs  40 , which are integrally formed as parts of the molded valve base  12 . The flapper positioning posts  38  are positioned such that they can loosely control the position of the flapper  28 . In particular, the gap between posts  38  is slightly larger than the width of the necked portion  36  of the flapper  28 . The allowance gap is defined by the process tolerance of injection molding. The retainer tabs  40  retain the diaphragm  32  in a position overlying the opening  26  in the valve base  12 . 
         [0032]    The flapper  28  provides the one-way airflow feature in valve assembly  10 . The valve can be opened by pressing portion  16  of the cap  14  (see  FIG. 4 ). Upon being pressed, the cap  14  will pivot around a pivot point and be in an open state when it reaches the angular position depicted in  FIG. 5 . When the cap  14  is pivoted to this valve open position, the flapper will be free to lift open in the allowed space underneath the cap. This cap position allows air to be extracted from the bag. A vacuum source (not shown) can be placed with the terminus of its nozzle pressed against the base flange  22  to draw air through the valve. The suction applied by the vacuum nozzle causes the diaphragm  32  to flex open. Then air inside the bag passes through opening  26  in base  12 , through vent holes  18  in cap  14 , and into the vacuum nozzle. The opening  26  in the base  12  is in fluid communication with the multiplicity of vent holes  18  in cap  14  when any portion of the diaphragm  32  is lifted off of the annular beads  42  and  44 . One such position of the diaphragm  32  is indicated in  FIG. 5  by dashed lines  32 ′. 
         [0033]    When the vacuum source nozzle is removed, diaphragm  32  returns to its original shape and bears against beads  42  and  44 . Once the pressure inside the bag is less than that of the outside atmospheric pressure, the “vacuum” inside the bag is maintained due to the atmospheric pressure applied onto the flapper&#39;s upper surface. The valve can then be securely closed by pressing down the portion of cap  14  that is diametrally opposite to portion  16 . The valve closed position of cap  14  is best seen in  FIG. 7 . 
         [0034]    Referring to  FIG. 7 , in the valve closed position the diaphragm of flapper  28  is held down by the rims of a pair of concentric downwardly depending walls  52  and  54  integrally formed on the cap  14 . More specifically, walls  52 ,  54  have heights designed so that their rims press the diaphragm  32  of flapper  28  against the beads  42 ,  44  of valve base  12 , thus creating an airtight seal that prevents air from flowing in a reverse direction through the opening  26  in base  12 . Preferably the wall  52  has a diameter slightly greater than the diameter of bead  42 , but less than the diameter of bead  44 , while wall  54  has a diameter less than the diameter of bead  42 . In this valve closed state. there is no fluid communication between opening  26  in base  12  and vent holes  18  in cap  14  (only one of the vent holes  18  is visible in  FIG. 7 ), that is, opening  26  is not a flow path for leakage of ambient air into the evacuated storage bag. 
         [0035]    As seen in  FIG. 5 , the valve assembly  10  is mounted to a wall  20  of a storage bag such that a flange  22  of base  12  is on the inside of the bag. Base  12  has an upright wall  24  that extends generally perpendicular to the plane of flange  22  and through a hole in the bag wall. The base  12  is held in place by welding the base flange  22  to the material of bag wall  20  to provide a seal. In a preferred embodiment, the valve base  12  is permanently attached to the bag wall  20  by heat sealing. The heat seal makes a complete circle around the circumference of the hole in the bag wall through which wall  24  of base  12  projects, thereby blocking the passage of air between the bag wall  20  and the base flange  22  and then out the hole in the bag wall. Optionally a retaining ring may be placed over the base  12  on the outside of the bag to cover the weld area on base flange  22 . 
         [0036]    As best seen in  FIG. 6 , a plurality of curved vanes  26  project downward from the bottom of the valve base to allow sufficient airflow paths (indicated by curved arrows in  FIG. 6 ) between the upper and lower bag film layers (not shown) and toward opening  26  in base  12  during evacuation. 
         [0037]    Optionally, means are provided on the flange  22  of base  12  for improving the speed of the conduction heat sealing operation by which the valve assembly is attached to the bag. As shown in  FIG. 5 , the foregoing means comprise a series of concentric circular beads formed on the upper surface of the flange  22  to which the bag wall  20  is joined. In the example shown in  FIG. 5 , three circular beads are provided, with the difference in radius of the outer and middle beads being equal to the difference in radius of the inner and middle beads. Each of the beads has a respective profile that is generally constant along its circumference, which profiles may be substantially the same for the three beads. During the sealing operation (sealing the base of the valve assembly to the bag making film), a portion of the bag making film on the periphery of the hole through which the valve base  12  passes is pressed between a heated annular sealing ring (not shown) and the flange  22  of base  12 . Portions of one or more of the beads are melted along the entire circumference of the sealing ring during the heat sealing operation, thereby providing an annular hermetic seal around the hole in the bag. The beads act as heat concentrators during the sealing operation. The beads melt rapidly and then fuse to the bag making film to form the hermetic seal during cooling. The presence of these heat-concentrating beads speeds up the conduction heat sealing process, thereby reducing the cost of manufacture. 
         [0038]    As best seen in  FIG. 8 , the pivotable cap  14  may comprise a pair of pivot hinges  60  formed by rounded projections in the shape of a section of a sphere. These pivot hinges are disposed on opposite sides of the cap and are seated in respective spherical pivot hinge indentations  62  formed on the inside of wall  24  of the valve base  12 . Below each pivot hinge  60 , the cap has respective round pivoting edges  65 . The round pivoting edges of the cap are supported by pivot support posts  64  and  66  (best seen in  FIG. 3 ), which are integrally molded as parts of the valve base  12 . 
         [0039]    Still referring to  FIG. 3 , the valve base  12  further comprises a pair of cap support posts  76  (only one of which is visible in  FIG. 3 ) that stop the cap  14  when it reaches the correct valve closed position during the valve closing operation (press to close). In addition, the valve base  12  comprises a pair of cap support ledges  78  (only one of which is visible in  FIG. 3 ) that provide additional support for the cap during the valve opening operation (press to open). Each ledge  78  has an inclined contact surface, as best seen in  FIG. 7 . 
         [0040]      FIG. 9  shows a cross-sectional view of an alternative embodiment of a valve assembly  10 ′. In this embodiment, the cap pivot hinges  68  of cap  14 ′ each have a round pivoting upper edge. Each cap pivot hinge  68  is received in a respective indentation on the inside of wall  24 ′ of the valve base  12 ′ when the cap  14 ′ is snapped into place. Pivot support posts similar to posts  64  and  66  seen in  FIG. 3  are also provided, which pivot support posts supports the round pivoting edges of cap  14 ′. 
         [0041]      FIG. 10  shows an isometric view, from above, of a valve assembly  70  with press-to-open cap  72  of alternative design. This valve assembly differs from the assembly seen in  FIG. 2  in the location and configuration of the vent holes  18 , but otherwise may have the same structure as described in detail above. 
         [0042]    The evacuable storage bag  2  (see  FIG. 1 ) may be constructed from two panels of film joined together (e.g., by conduction heat sealing) along three sides of a rectangle. To maintain a vacuum inside the storage bag, the zipper  8  in a closed state must provide a hermetic seal at the mouth (i.e., fourth side) of the bag. Many different types of zippers can be used. The present invention is not directed to any particular zipper construction. For the sake of illustration, however, a suitable zipper for use with the present invention is described in U.S. Published Patent Application Publ. No. 2005/0211319 (see  FIG. 13  therein and associated description), the contents of which is fully incorporated by reference herein. 
         [0043]    The person skilled in the art of manufacturing reclosable bags on a machine would readily appreciate that instead of forming the bag from two separate webs of plastic film joined together on three sides, the bag can be formed from a single web of film that has been folded. In the completed bag, this fold will form the bottom of the bag, while the two side seals are formed by conduction heat sealing. 
         [0044]    While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 
         [0045]    As used in the claims, the verb “joined” means fused, bonded, sealed, tacked, adhered, etc., whether by application of heat and/or pressure, application of ultrasonic energy, application of a layer of adhesive material or bonding agent, interposition of an adhesive or bonding strip, etc.