Patent Publication Number: US-2006008187-A1

Title: Reclosable bag

Description:
FIELD OF THE INVENTION  
      This invention relates to the general field of containers, and more particularly to multi-purpose and specialty storage bags.  
     BACKGROUND OF THE INVENTION  
      Bags are universally used and recognized as convenient, versatile, lightweight, and low cost containers. Bags having recloseable openings are useful to provide better security for their contents and for storage purposes. Such bags also have the benefit of better protecting perishable or sensitive contents, or alternatively, protecting the environment from contamination by contents that are toxic or dangerous.  
      A common closeable bag configuration has two rectangular panes of plastic film joined along three sides, with an opening left on one side, usually the top. A reclosable opening or zipper can be constructed on the open side by forming an interlocking strip on opposing panes, for example, by tongue and groove portions. The bags may be conveniently closed by pinching the panes together, so the tongue snaps into the groove, and opened by prying the panes apart.  
      In some cases a slider is added to facilitate opening and closing of the bag. A slider is a separate, usually molded, plastic piece that fits over and around the edge of the panes forming the bag opening so that it can slide along the strip. The slider is usually configured to apply an inward pinching pressure to urge opposing panels to join or interlock, and also to include a separator or finger that traverses the bag opening. With this configuration, closing the bag involves pushing the slider in a closing direction, and opening the bag involves moving the slider along a reverse, opening direction.  
      In many applications such as storage of food, liquids, or biological waste, it is desirable to form an airtight or leakproof seal of the closed bag. However, for bags having sliders, the separator or finger part of the slider usually traverses the opening, which prevents the formation of an airtight seal. In one attempted solution, Blythe, U.S. Pat. No. 6,526,632, shows a slider which lifts the separation member out of the bag opening by rotating the slider upwardly at the closed end. This device however is more complicated than the conventional slider, which adds cost, and also apparently depends on use of a customized counterpart fastener  12 .  
      Another desirable feature, particularly for perishable contents, is the ability to remove residual air from the interior of the closed bag. A common practice by users of household storage bags, for example, is to first close the bag almost all the way, leaving a small portion open. The bag is then squeezed to vent the residual air out through the small opening, after which the user tries to quickly close the small opening before air can re-enter the bag. This informal method however is generally inconvenient and produces inconsistent results. It is also awkward, particularly for individuals with poor motor skills.  
      Some attempts have been made to construct a closeable bag with a built-in facility for air removal. For example, Minica, U.S. Pat. No. 6,045,264, shows a bag having an open top divided into a main opening and a smaller evacuation opening. The latter opening is configured to include a suction conduit for use in removing residual interior air. Strong, U.S. Pat. No. 5,839,582, shows a bag having a bow-shaped pump chamber with a suction port and a one-way valve. When the bag is closed, the pump chamber can be compressed to push air out through the one-way valve. Herrington, U.S. Pat. No. 4,532,652, shows an extending portion adhering to a hole in one of the film side panels. Squeezing the bag causes the extending portion to separate from the side panel, permitting air to escape through the hole. Thereafter, the extending portion returns to its position covering the hole, preventing further outflow of interior air.  
      All of these devices require modification to the standard storage bag, which increases cost. In addition, the bags shown do not use a slider, which may be due to the difficulty of forming an airtight seal with a slider.  
      A related problem is that the configuration of the panes of the bag can affect the degree to which an airtight seal can be achieved. Where the bag is formed from panes that are both flat or smooth, the panes can stick together over at least a portion of the pane area and block any applied suction from reaching the bottom portions of the bag. This could leave air bubbles trapped in the bag. One attempted solution is to use a ribbed pane, so that air channels are created between the ribs that reach deeper parts of the bag. However, there is still a problem in that the negative pressure formed inside the bag due to removal of air creates a tendency to pull or draw ambient air back into the bag interior through the closed zipper at the top of the bag. It can therefore be very difficult to create and maintain an airtight vacuum inside a closeable bag.  
     SUMMARY OF THE INVENTION  
      What is desired is a reclosable bag which overcomes one or more of the problems associated with such prior art bags.  
      Preferably, the bag should be easy and convenient for the user to close. In particular, it would be preferable if the bag could be configured to make use of a slider, which facilitates a strong air tight seal and the opening and closing thereof. A strong seal better maintains the freshness of perishable contents, and better protects the environment from toxic contents. The bag will also preferably be configured so that after it is closed the user can conveniently remove residual air, gas, or fluids from the bag interior, or alternatively, fill the interior with gas or fluid without disturbing the air-tight seal.  
      To keep costs low, the bag will preferably be capable of manufacture by conventional production techniques, using standard materials and components. The bag will preferably be suitable for production as a general purpose storage bag or as a commercial container for drinks and other items. Another preferable feature would be for the bag&#39;s closeable opening characteristic to be changeable. In this way, instead of the usual configuration where one side of the slider opens the bag and the other side closes the bag, the bag opening could be made, for example, to stay closed on either side of the slider as the slider is moved. This feature could enable greater flexibility in producing closeable bags that more closely meet the needs of different applications. It would also be preferable for the bag to effectively hold liquids, and to have a feature that prevents inadvertent spilling. The bag will also preferably enable an airtight vacuum to be formed and maintained within its interior, such as upon the application of suction to remove gas or air inside the bag.  
      Accordingly, there is provided a reclosable bag having a bag interior and a bag opening, the bag interior comprising: 
          (a) a sealing section;     (b) an air-flow section configured to permit air flow through said air-flow section; and     (c) an air access interface positioned between the air-flow section and the sealing section, and configured to permit fluid communication therebetween; 
            the bag further comprising:     (i) an openable closure configured and positioned to open and close the bag opening, the sealing section being positioned between the closure and the air-flow section; and     (ii) a valve configured and positioned to permit air to be removed from the bag interior through the valve so as to create a negative pressure in the bag interior relative to an exterior of the bag;     the sealing section being configured such that, when there is said negative pressure and the closure is closed, air is blocked from leaking from said exterior through said closure and sealing section to the air-flow section.   
               

    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Reference will now be made, by way of example only, to preferred embodiments of the invention as illustrated in the attached figures.  
       FIG. 1  is a perspective view of the reclosable bag of the present invention with the slider in an intermediate position;  
       FIG. 2  is a perspective view of the reclosable bag of  FIG. 1 , with the slider in a closed or sealed position;  
       FIG. 3   a  is a cross-sectional view of the reclosable bag of  FIG. 1 , showing the bag in an non-interlocked position;  
       FIG. 3   b  is the same view as  FIG. 3   a,  showing the bag in an interlocked position;  
       FIG. 4  is a cross-sectional view of the slider of the present invention installed in the bag;  
       FIG. 5  is a perspective view of the slider of  FIG. 1  showing hidden elements;  
       FIG. 6  is a side view of the slider of  FIG. 1 , without a handle;  
       FIG. 7   a  is a perspective, hidden view of the slider of the present invention showing the opening edge of the slider;  
       FIG. 7   b  is the slider of  FIG. 7   a  rotated to show the other side of the slider;  
       FIG. 7   c  is the slider of  FIG. 7   a  viewed from the front;  
       FIG. 8   a  is a perspective, hidden view of the slider of the present invention showing the closing edge of the slider;  
       FIG. 8   b  is the slider of  FIG. 8   a  rotated to show the other side of the slider;  
       FIG. 8   c  is is the slider of  FIG. 8   a  viewed from the front;  
       FIG. 9   a  is a front view of the closing edge of the slider of  FIG. 9 , with one side of the slider left blank;  
       FIG. 9   b  is the same view as  FIG. 9   a  with the other side of the slider left blank;  
       FIG. 10  is a perspective view of the bag of  FIG. 1 , showing a suction device in the slider passageway and contents in the bag interior;  
       FIG. 11  is a perspective view of another embodiment of the reclosable bag of the present invention, showing a fixed element and a slider;  
       FIG. 12  is a perspective view of another embodiment of the reclosable bag of the present invention, showing a round commercial drink package; and  
       FIG. 13  is a perspective view of another embodiment of the reclosable bag of the present invention, showing a gussetted commercial drink package;  
       FIG. 14  is a top view of another embodiment of the reclosable bag of the present invention; and  
       FIG. 15  is a further view of the bag of  FIG. 14 , containing an object and having an internal vacuum. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The closeable bag of the present invention is shown in  FIG. 1 , and is generally indicated with reference numeral  10 . There is a bag portion  12  which defines a bag interior  14 . The bag portion is generally sealed or closed along its edges except for a bag opening  16 , which defines an unsealed section that can be selectively opened or closed. In  FIG. 1  bag opening  16  is the top unsealed side of the bag between end  22  and end  24 .  
      The closeable bag includes a means for selectively opening and closing the bag opening. The means for opening and closing generally comprises two elements—opposed interlocking features  18  along the bag opening  16 , and a slider  20 . The slider  20  is positioned in the bag opening  16 , between the opposed interlocking features  18 , and is generally movable along at least a portion of their length. The slider  20  is further configured so that as it moves, it causes the portion of the opposed interlocking features  18  that it passes to engage or disengage.  
      In  FIG. 1 , the slider  20  is shown at an intermediate position between end  22  and end  24  of the bag opening  16 . In this position the opposed interlocking features  18  are engaged for a closed portion  15  of the bag opening  16  between the end  22  and the slider  20 , and are disengaged for an open portion  17  of the bag opening  16  between the slider  20  and the end  24 . In  FIG. 2 , the closeable bag  10  is shown with the slider  20  moved all the way to the end  24 . It can be seen that in this position the opposed interlocking features  18  are engaged along the complete length, from end  22  to end  24 , of the bag opening  16 . It can be appreciated that in this position of the slider  20 , closed portion  15  is at a maximum length.  
      The closeable bag  10  is configured so that when the slider is in the position shown in  FIG. 2 , in which the interlocking features  18  are fully engaged and the bag opening  16  is completely closed, the bag  10  is generally sealed airtight. The invention also comprehends a passageway  26  to provide access between the bag interior  14  and an outside area  28  of the bag, and a means for selectively opening and closing the passageway. In  FIG. 1 , the passageway  26  is shown inside the slider  20 . The bag of the present invention can accordingly selectively provide access, through the passageway  26 , between the bag interior  14  and outside area  28  when the bag opening  16  is completely closed and the bag  10  is otherwise sealed airtight.  
      The bag portion  12  of the present invention comprehends any structure that provides the function of a container or a bag. More specifically, the bag portion  12  defines the bag interior  14 , which is a space inside the bag with a capacity to receive various contents for deposit.  
      The bag opening  16  represents an area or space through which access may be obtained to the bag interior  14 . Depending on the application, the bag contents may be deposited or retrieved through the bag opening  16 . The bag opening  16  is preferably formed by an unsealed or unconnected seam of the material used to form the bag portion  12 , but may also be formed by a cut, slit, incision, gap, hole, or other break anywhere on the surface of that material. The position of the bag opening  16  may accordingly be along an edge, interface, or seam of two or more pieces of the bag material, or along a top, bottom, side, diagonal, or other section of the material.  
      As shown in a preferred embodiment of  FIG. 1 , a simple bag portion  12  may be created by joining two rectangular panes of material along three of their four sides. Alternatively, the embodiment of  FIG. 1  could also be made by folding a single sheet of material to form the two panes, and sealing the two sides. For convenient reference, the two panes may be designated as a front pane  30  and a back pane  32 . In this embodiment the bag interior  14  is the volume of space between the two panes  30  and  32 , and the bag opening  16  is the area bounded on its perimeter by the edges of the two panes on the unsealed top side of the bag.  
      The bag portion  12  also preferably includes a support feature  33  adjacent to the bag opening  16  on an exterior part of the bag. The support feature  33  may take the form, for example, of a ridge, ledge, bulge, or similar protrusion. In the bag of  FIG. 1 , support feature  33  is a thickening or bulging of the bag material along the edge of the top open side of each pane of the bag. As will be discussed in greater detail below, feature  33  provides a surface that facilitates support or attachment of the slider  20 .  
      It can be appreciated that other embodiments of the bag portion  12  are possible as long as they define a bag interior  14  capable of holding contents, and a bag opening  16  to provide access to the bag interior. Some examples of alternative embodiments include a bag portion  12  formed from a single piece of spherical material having no panes or seams, as shown in  FIG. 12 , or a more complex gusseted bag having six panes, as shown in  FIG. 13 . In these embodiments the bag opening  16  may be formed by an incision or cut in the material forming the bag portion  12 .  
      The bag portion  12  is preferably formed from a material sufficiently dense to contain air, gas, liquid, or other fluid contents without leakage, and sufficiently strong to hold the expected contents without tearing. The material should preferably be water resistant so as not to lose structural strength from contact with liquids. For these reasons bags made of plastic or polyethylene have been found to be adequate. Depending on the application, other materials such as film, laminate, or coated or treated paper may also provide adequate results. The bag material is preferably smooth, but may also be made laminated. Laminations are sometimes preferable, particularly in larger bags, since they can can provide channels for the movement of air flow inside the bag interior  14 .  
      To retain the flexibility characteristic of bags the material should also preferably be pliant or elastic. The degree of flexibility in the material can be varied according to the application. However, it is preferable that there be at least sufficient flexibility so that the part of the bag portion  12  that defines the perimeter of the bag opening  16  can be pulled or drawn together by a user, to effectively close the bag opening  16 .  
      The bag  10  of the present invention is generally configured to be closed or sealed everywhere on its surface and at all seams and edges except for bag opening  16 , which can be selectively opened or closed. Therefore, closing bag opening  16  has the effect of completely enclosing bag interior  14  and closing the bag  10 . The bag  10  may be designated alternately as “closeable” or “recloseable”, in each case meaning that the bag can be repeatedly opened and closed.  
      In  FIG. 1  the bag opening  16  is formed in the space between the top edges of the unsealed sides of opposed panes  30  and  32 . Interlocking features  18  are installed on the inner part of the opposed panes  30  and  32  that form the perimeter of bag opening  16 . The interlocking features  18  may be more particularly referenced as interlocking or front feature  34  on front pane  30  (not visible in  FIG. 1 ) and interlocking or back feature  36  on back pane  32 . The interlocking features  18  are positioned to oppose one another and are sized and shaped to engage and close bag opening  16  when panes  30  and  32  are brought together.  
      In the preferred embodiment of  FIG. 1  the position of the interlocking features  18  is at the top inner edge of panes  30  and  32 . This positioning is preferred because it maximizes the interior space  14  of the bag  10 . However it can be appreciated that the interlocking features  18  may be placed anywhere on the bag  10  and oriented in any direction as long as it forms an opposed pair sized and shaped to close bag opening  16  when engaged.  
      The interlocking features  18  represent any configuration which will enable the opposed panes of the bag portion  12  to engage when the panes are brought together or in close proximity, to close bag opening  16 , and also comprehend any configuration which will enable the engaged panes to disengage when the panes are drawn or pulled apart, to re-open bag opening  16 . The interlocking features  18  should preferably be sufficiently robust in design and composition to enable repeated opening and closing within the expected lifespan of the bag  10  without experiencing undue loss in the strength of the engaged portions. In addition, the interlocking features are preferably sized and shaped to form a seal when engaged. In this way, fluid contents in the bag interior  14 , for example, would not leak out of the bag through the engaged interlocking features.  
      A preferred type of interlocking feature  18  comprises mechanical elements which interlock through an interference or snap fit, such as by one feature sliding, pressing, or snapping inside the other feature. Such an arrangement is commonly described as a “tongue and groove” or “male and female” configuration, with the inner piece being the tongue or male portion and the outer piece being the groove or female portion.  FIG. 3  shows a cross-sectional view of a preferred embodiment of the interlocking features  18 . In  FIG. 3   a  there is a male or tongue feature  34  and a female or groove feature  36 . In this figure the opposing interlocking features are not connected or engaged, so that bag opening  16  is open. In  FIG. 3   b  the features  34  and  36  are engaged in that tongue feature  34  is inserted into groove feature  36  by a snap fit. The features  34  and  36  are preferably formed from the same plastic material as the panes  30  and  32 , and are sized and shaped so that tongue  34  fits snugly inside groove  36 . The combination of the close fit and resiliency of the material cause the engaged pair to form an effective seal, and to resist disengagement unless a minimum sufficient force is applied to opposed panes  30  and  32  to pull them apart. It can be appreciated that the larger the tongue feature  34  is relative to the groove feature  36 , the harder it will be to snap fit the features together, but the stronger will be the connection and the tighter will be the seal.  
      The preferred arrangement shown in  FIG. 3  has been found to be generally adequate, particularly for low cost applications, as it provides adequate performance and can be produced at low cost. However, it can be appreciated that other types of interlocking features  18  are comprehended by the present invention as long as they retain the properties of being able to engage or disengage without too much difficulty, maintain a minimum sufficient strength of engagement, and retain this strength of engagement after repeated openings and closings. Other possible embodiments may include, for example, magnetic means of engaging or disengaging opposing panes.  
      The slider  20  is preferably an independent piece or element separate from the bag portion  12 .  FIGS. 5-9  show various views of a preferred embodiment of the slider  20 , where for enhanced clarity the independent slider element is shown isolated, or unconnected to the bag portion  12 .  
      With reference to  FIG. 5 , the slider  20  generally comprises a central or core body  38  with projecting handles  40  on either side. The body  38  has a top  42 , a bottom  44 , and a pair of sides or side faces  46 , which for clarity are further distinguished as side face  45  and side face  47 . The side faces  46  comprise the part of the slider  20  that face or make contact with the opposed interlocking features  18  of the bag  12 .  
      It can be seen through the hidden view of  FIG. 5  that the core body  38  is widest at the center and tapers to opposing tips, ends, or edges  48 ,  50 . Each of the edges  48  and  50  extend the length from the top  42  to bottom  44  of the core body  38 . The slider  20  is also preferably sized and shaped to be complementary to the shape of an end of the bag opening, to permit the slider to form a better seal. As a result of this preferred configuration, in a top view the body  38  resembles a flattened oval terminating in a point at each end. This aspect of the slider  20  may also be seen in  FIGS. 1 and 2  which show, in hidden lines, the upper edges of panels  30  and  32  in bag opening  16  wrapping around the oval-shaped core body  38  of slider  20 .  
      The handles  40  provide support to keep the slider  20  in place or attached to the bag  12 , and also provide a handle, grip, or contact for the user to hold when moving the slider. The handles  40  preferably attach to or extend from the slider body  38  at or near the top  42 , and extend outwards to either side and downwards towards bottom  44  to some extent. It is also preferable for the bottom of the handle to extend inwards towards the body  38 , to create a support ledge  52 . In  FIG. 5  the handles  40  include an outward panel  53 , downward panel  54 , and inward panel  55 . However it can be appreciated that handles  40  formed from a single curved panel, for example, would also be adequate. In another embodiment that provides greater surface area, the handles  40  could rise vertically above top  42  of the slider body before turning outwards and downwards.  
      It can be appreciated that the handles  40  include both an inside portion that faces the sides  46  of the slider and an outside portion that faces away from the sides  46  of the slider. The outside portion provides a surface which may be grasped by a user to hold or move the slider  20 . Accordingly, the handles  40  and in particular the outside portion of handles  40  are preferably sized and shaped to provide a comfortable and secure gripping surface. This may include, for example, in panel  54 , an indentation in the surface or the use of a rubber material with nodules to provide a more effective grip.  
      The handles  40  are also preferably sized and shaped so that the inside portion generally follows the contour of the sides  46  of the slider. In the preferred embodiment of  FIG. 5 , the inside portion of the handles  40  will accordingly follow the oval contour of the core body  38 , which expands outwards from ends  48  and  50  towards the center of the body. As can be seen in the drawings, the handles  40  and their inside portion extend all the way towards end  48  of the slider body  38 , but stop short from end  50 . The reason for this configuration relates to different functions served by ends  48  and  50 , and is discussed in greater detail below.  
      The slider  20  is also preferably configured so that the separation or gap distance between the sides  46  of the body  38  and the inside portion of the handles  40  will be approximately the thickness of the individual panels  30  and  32 , along the bag opening  16 , of the bag portion  12 . More preferably, the separation or gap distance will be slightly greater than the bag panel thickness, so that there will be sufficient space for the bag panels to be inserted and fit between the slider body  38  and handles  40 , while maintaining a close and secure connection.  
       FIGS. 7 and 8  provide enhanced views of the side faces  46  of the slider  20 . For greater clarity, in these figures the handles  40  are shown in outline so that the slider body  38  and sides  46  can be more clearly viewed. It can be seen that each of the individual side faces  45  and  47  have a side rail  56 , or more particularly side rail  58  on side face  45  and side rail  60  on side face  47 . The side rails  56  are sized and shaped to mate with or slidably engage an opposing interlocking feature  18  on the bag portion  12 , and accordingly are preferably configured as a tongue or a groove. It can be seen from  FIGS. 7   a  and  8   b  that side rail  58  comprises a tongue or male connector, and from  FIGS. 7   b  and  8   a  that side rail  60  comprises a groove or female connector.  
      The side rails  56  are preferably positioned in the middle of the body  38 , equidistant from the top  42  and bottom  44 . The side rails  56  are also preferably formed by carving the desired feature, whether tongue or groove, out of the side  46  so that side  46  maintains a flat or flush profile.  
      The side rails  56  generally extend the length of the sides  46 , but vary in configuration according to which end,  48  or  50 , is being approached. End or edge  50  is highlighted in  FIG. 7 , with  FIG. 7   a  providing a perspective view of side  45  and tongue side rail  58 ,  FIG. 7   b  providing a perspective view of side  47  and groove side rail  60 , and  FIG. 7   c  providing a front view of both sides and side rails. It can be seen that the side rails  56  terminate just before edge  50 , and do not interact, abut, or otherwise contact one another. Edge  50  in effect separates the side rails  56 , and accordingly maintains a generally continuous, unbroken line from top  42  to bottom  44  of the slider body  38 .  
      Similarly, end or edge  48  is highlighted in  FIG. 8 , with  FIG. 8   a  providing a perspective view of side  47  and groove side rail  60 ,  FIG. 8   b  providing a perspective view of side  45  and tongue side rail  58 , and  FIG. 8   c  providing a front view of both sides and side rails. In this case the side rails  56  intersect, producing a hollowed out section  62  where they meet along edge  48 .  
       FIG. 9  has been provided to enhance clarity of the configuration of edge  48 . In  FIG. 9   a  groove side rail  60  is shown but side  45  has been left blank, without side rail  58 , for illustration purposes. It can be seen that the groove  60  extends all the way to the edge  48  and wraps around it so that the groove carves out a small portion of side  45 . Similarly, in  FIG. 9   b  tongue side rail  58  is shown with side  47  left blank. In this case the tongue  58  also extends all the way to edge  48  and wraps around it, thereby extending into side  47 . When the two side rails of  FIG. 9  combine, the result is the hollowed out section  62  along edge  48  shown in the various views of  FIG. 8 .  
       FIG. 6  is a side or profile view of the slider body  38 , taken along side  47  and showing groove side rail  60 . It can be seen that edge  50  remains continuous and unbroken, as side rail  60  and side rail  58  (not shown) both terminate just before the edge. By contrast, side rail  60  extends all the way to edge  48  and wraps around it, along with side rail  58  (not shown) creating hollowed out section  62 . As will be discussed in more detail below, the configuration of side rails at edge  50  has the effect of disengaging the opposed interlocking features  18 , while the configuration at edge  48  engages the interlocking features  18 . For this reason, the slider ends may alternatively be designated as opening or separating edge  50  and closing or joining edge  48 .  
      Opening edge  50  can be made to form a straight vertical edge. However, as shown in  FIG. 6  and  FIGS. 7   a  and  7   b,  edge  50  is preferably configured to include a projection or jutting portion  64  at one or more places along its length. The projection portion  64  is sized and shaped to make slider  20  form a closer, more complementary fit with the end of bag opening  16 . In this way, a more effective seal will be created when the slider is moved to an end of bag opening  16 , as shown in  FIG. 2 .  
      Slider  20  also preferably includes the passageway  26 , which is an aperture or hole extending the full height of the slider from top  42  to bottom  44 .  FIG. 5  shows the slider  20  with the hidden part of passageway  26  shown in dotted line. The passageway can have any cross-sectional shape, such as circular, oval, or rectangular, but is preferably circular. It can be located anywhere on the slider, but preferably is located at or close to the center or midpoint of the slider. The passageway  26  can be any size in diameter or width as long as it does not interfere with the structural integrity of the slider. The passageway is also preferably sized and shaped to to permit gas, fluid, or solid matter to flow or pass through its interior, and to accept a fluid transmission conduit, as discussed further below.  
      The slider  20  is preferably made from a polyethylene or plastic material. Plastic is preferred because it is relatively strong, lightweight, water resistant, and low cost. A further advantage of plastic is that it can be made relatively easily into a complex shape like the slider  20 . This can be accomplished, for example, through the standard production technique of injection molding, using a standard mold designed to conform to the shape of the slider  20 . Plastic is also a preferable slider material to use when the bag portion  12  is plastic, so that the various components can be more easily integrated. It can be appreciated that other materials are also comprehended by the present invention as long as they possess some or all of the above properties. Other possible materials for the slider may include, for example, metal, alloy, or wood.  
      In forming the bag  10  of the present invention, the body  38  of the slider  20  is placed inside the bag opening  16  so that sides  46  are positioned between the opposed faces of front feature  34  and back feature  36 . As shown in  FIG. 4  in cross-sectional view, the slider  20  attaches to the bag portion  12  on both the inside and the outside of the bag.  
      On the inside of the bag, the side rails  56  of the slider mate or slidably engage with the opposed interlocking features  18  of the bag portion  12 . With respect to the embodiment of  FIG. 4 , the tongue of front feature  34  snaps or fits inside the groove of side rail  58 , and the tongue of side rail  60  snaps or fits inside the groove of back feature  36 . It can be appreciated that other embodiments of these interacting elements are also possible, as long as the slider slidably engages with the bag portion  12 . For example, the interlocking features  18  could be made flush with the bag portion  12 , with the side rails  58  and  60  projecting outwards from the sides of the slider.  
      On the outside of the bag, it can be seen that the handles  40  of the slider are sized and shaped to conform to or snugly fit with the external support feature  33  of the bag portion  12 . In particular, the handles  40  wrap around support feature  33  so that the bottom of support feature  33  rests on support ledge  52  of the handles  40 . It can be appreciated that other embodiments of these elements are also possible as long as the handles provide a means for securing the slider to the outside of the bag portion  12 . For example, the particular shapes of the support feature  33  and handles  40  can vary as long as they continue to conform to one another to form a close, snug fit. Similarly, other types of attachment besides a mechanical fit are also possible, such as for example, a magnetic connection between the inside of the handles  40  and the opposing external edge of the bag portion  12  or support feature  33 .  
      It can be appreciated that the combination of the interlocking elements inside the bag and the close fit of the handle around the external support feature  33  closely hold the slider  20  to the bag portion  12 . In particular, the slider  20  is attached so that it cannot fall into the bag interior  14  or inadvertently pop out of the open top. Short of a determined and forceful effort, the slider  20  will resist most attempts to be separated or removed from the bag portion  12 .  
      The slider  20  is sized and shaped to engage the interlocking features  18 , or alternatively, to disengage the interlocking features  18 , as the slider is moved along the bag opening  16 . More specifically, the configuration of edges  48  and  50  of the slider  20  determine whether a given portion of bag opening  16  will engage or disengage as the slider moves in a particular direction.  
      Turning to the preferred embodiment of the closeable bag  10  shown in  FIG. 1 , it can be seen that from an intermediate position the slider  20  can be moved in two directions, towards either end  22  or end  24 . In whichever direction the slider is moved, one of the slider edges  48  or  50  will face the end in the direction of movement, and the other one will trail, facing the opposite end. The bag  10  of the present invention is configured so that as the slider is moved along a portion of bag opening  16 , the interlocking features  18  in the portion covered by the slider movement will join or engage, or alternatively, separate or disengage, in accordance with the characteristic of the trailing end or edge of the slider  20 .  
      More particularly, in  FIG. 1  the slider  20  is oriented so that joining edge  48  faces end  22  of the bag  10 , or closed portion  15  of the bag opening  16 , and separating edge  50  faces end  24  of the bag, or open portion  17  of the bag opening  16 . As slider  20  is moved towards end  24 , the interlocking features  18  will join, close, engage, or interlock in accordance with trailing joining edge  48 . In this way, closed portion  15  will increase in length commensurate with open portion  17  decreasing in length. As shown in  FIG. 2 , when the slider reaches end  24  the entire length of interlocking features  18  will be closed. Similarly, as slider  20  moves towards end  22 , as for example in moving from the position in  FIG. 2  to the position in  FIG. 1 , the interlocking features  18  will separate, open, or disengage, in accordance with trailing separating edge  50 .  
      The joining and separating function of the slider  20  can be understood by tracing the path of the interlocking features  18  through edges  48  and  50  of slider  20 . As shown in  FIG. 4 , the interlocking features are slidably engaged with side rails  56  over most of the length of sides  46  of the slider. As the slider of  FIG. 1  moves towards end  24 , the portion of the interlocking features that pass through trailing edge  48  will be drawn together due to the continuation of the side rails right up to and around the edge  48 . As each side rail wraps around the opposite side at edge  48 , the slidably engaged tongue and groove features  34  and  36  will be forced into contact, with tongue  34  snapping or pressing into groove  36 . Further, the inner portion of handle  40  follows the contour of sides  46  all the way to edge  48 . Since the gap or separation distance between the inner portion of the handle  40  and sides  46  is very small, and preferably only marginally thicker than the thickness of the upper edges of individual panes  30  and  32 , the panes  30  and  32  will be forced to stay in the track of side rails  56  and forced to come together. In this way, the interlocking features  18  make a smooth transition from being slidably engaged with side rails  46  of the slider, as for example shown at  65  and  66  of  FIG. 1 , to being interlocked with one another, as shown in their corresponding positions on the closed portion  15  of  FIG. 2 .  
      Conversely, when the slider  20  moves towards end  22 , the portion of the opposing features  34  and  36  that pass through trailing edge  50  will be unable to engage due to the termination of the side rails  56  on either side of separating edge  50 . Further, the inner portion of handle  40  only follows the contour of sides  46  to a point short of separating edge  50 . There is no need for the inner portion of handle  40  to extend all the way since it is not desired to press the interlocking features together at separating edge  50 . As a result, while the opposing features  34  and  36  will approach one another as the contour of slider  20  narrows towards edge  50 , as they slip off the side rails  56  they will remain apart since there is no guide or track on the slider side rails or outside pressure from the handles  40  to keep them together.  
      It can be appreciated that other open/close characteristics of the closeable bag  10  can be achieved by modifying the construction of the slider  20 . For example, instead of having both a joining edge  48  and a separating edge  50 , the slider  20  could be made with two joining edges  48 . In this case the bag opening  16  would remain closed for its entire length, on both sides of the slider, for any position of the slider. Alternatively, if the slider is constructed with two separating edges  50 , no part of the bag opening  16  would close.  
      The closeable bag  10  is configured to produce an airtight seal in the bag interior  14  when the bag opening  16  is fully closed. As shown in  FIG. 2 , this will occur where the slider  20  is moved to the sealed position at end  24 .  
      The interlocking features of the present invention are preferably sized and shaped to form a seal when engaged. In particular, the tongue feature  34  and groove feature  36  are preferably sized and shaped to form an airtight seal when they interlock or snap-fit together. Accordingly, with the slider  20  in the position shown in  FIG. 2 , the closed portion  15  of bag opening  16  from end  22  to end  48  of the slider will be airtight due to the engagement of interlocking features  18 .  
      The slider  20  is configured to seal the bag opening  16  when positioned at one end of said bag opening. Slider  20  is accordingly preferably configured to produce a seal all around its perimeter. At the point where closed portion  15  meets joining edge  48 , the interlocking features  18  are squeezed closely together, both from the inward pressure of the close-fitting handles, and to connect with side rails  56 . In this way the airtight seal is maintained at the interface of the interlocking features  18  and the slider. Along the sides  46  of the slider the airtight seal is maintained due to the snap fit between side rails  56  and interlocking features  18 . Accordingly, side rails  56  are preferably sized and shaped to produce an airtight fit or engagement with interlocking features  18 . At the interface of separating edge  50  and end  24  of the bag  10 , the airtight seal is achieved by configuring the slider  20 , and in particular separating edge  50 , so that it is complementary to the shape of bag opening  16  at end  24 . In the preferred embodiment of the bag  10 , the edge  50  of the slider has a “V” shape which complements and fits closely into a similar “V” shape in bag opening  16  at end  24 . Separating edge  50  preferably also includes the projection or jutting portion  64 . As shown in the side view of  FIG. 6 , this feature assists in maintaining an airtight seal by jutting out from the slider to fill any incremental space that may be present in bag opening  16 , at end  24 , through which air might leak.  
      It can be appreciated that other shapes of the slider  20  and bag portions  12  may also be used, as long as the shapes of the slider tip and end of bag opening  16  are sufficiently complementary to form a close and snug fit. It can also be appreciated how the present invention improves on the prior art. Sliders used in the past usually contain a separator or finger to separate or pry apart the panes. The separator is usually configured to fulfill this function, and not to form a complementary fit with a bag opening. Such sliders cannot usually seal a bag opening in the ordinary course since the separator prevents the slider from completely closing the bag opening.  
      In order to maintain the airtight seal once the slider has reached the end  24 , it is preferable for there to be a latch or other means to hold the slider  20  in place and prevent it from falling back. This may be achieved in the present invention by means of a detent, which is a catch or lever that locks the movement of one part of a mechanism. Detents can be placed anywhere along the slider  20  or the bag portion  12 .  
      In the preferred embodiment of  FIG. 1 , the bag portion  12  contains a first detent  68 , and the slider  20  contains a second detent  70  on the inside of handle  40 . The first detent  68  and the second detent  70  are configured to engage one another when the slider is moved to the sealed position. The first detent  68  is preferably a bump or raised nodule on the outside surface of the bag portion  12 , such as on external support feature  33 . The second detent  70  is preferably an indentation on the inside of handle  40 . When the slider  20  is moved to the sealed position, the detent  68  snaps into or engages with detent  70 . The connection established is preferably sufficiently strong to hold the slider  20  in place, while at the same time capable of being overcome without too much difficulty by the user pushing the slider towards end  22  when it is desired to re-open the bag.  
      It can be appreciated that other embodiments for latching of the slider are possible, as long as the slider  20  is prevented from falling back and a good seal is maintained. For example,  FIG. 10  shows the slider  20  having a flap  72  resting on the top  42  of the slider. At the sealed position shown in  FIG. 10 , the flap may be moved, rotated, or otherwise positioned to snap fit with a detent (not shown) on the outside edge of the bag portion  12 . When it is desired to move the slider, the flap  72  can be flipped up and out of the way, to restore mobility to the slider.  
      The passageway  26  is configured to provide access between the bag interior  14  and outside area  28  whether the bag opening  16  is open or closed. In the preferred embodiment of the invention, passageway  26  is preferably inside or integrated with slider  20 . Since the slider is positioned between interlocking features  18 , it can be appreciated that access between bag interior  14  and outside area  28  through passageway  26  will be unaffected even when the bag opening  16  is closed and sealed airtight. The passageway  26  is sized and shaped to provide access to passage of a fluid, such as a gas or a liquid, or solid matter such as particulates or powder.  
      The passageway  26  is also preferably sized and shaped to accept a fluid transmission conduit  74  such as a pipe, tube, or common straw. A general representation of a tube  74  is shown in  FIG. 10 . Such a device when coupled to the passageway from outside  28  of the bag would permit the application of suction, for example, to remove fluid from bag interior  14  through the passageway  26 . More particularly, a suction device having a coupling or insertion end  76  and a free end  78  may be coupled to the passageway  26  on the top surface  42  of the slider. Suction may be applied at the free end  78  to remove contents such as liquid or gas fluid from the bag interior  14 . In an industrial setting the suction will preferably be applied by a mechanical vacuum device. In a consumer product suction will preferably be applied by the user&#39;s mouth acting on the free end  78  of a straw. Preferably, the fluid transmission conduit  74  will be removable, and the passageway  26  will accordingly be sized and shaped to couple and uncouple with the removable conduit  74 . In this way, after the fluid is removed from bag interior  14  the tube  74  may be conveniently removed so it does not interfere with use of the bag  10  as a storage container.  
      The passageway  26  preferably contains a means for opening and closing the passageway, or valve  80 , as shown in  FIG. 5 . The valve  80  is any kind of device or structure that is positioned inside the passageway  26 , and that is sized, shaped, and configured to have at least one closed state and at least one open state. When the valve  80  is in its closed state, fluid flow through the passageway  26  will be blocked. In this state, if the bag opening  16  is completely closed, there will be an airtight seal of bag interior  14 . When the valve  80  is in an open state, access or fluid flow between the bag interior  14  and outside  28  of the bag will be enabled. It can be appreciated that when the valve  80  is in an open state and the bag opening  16  is completely closed, access to the bag interior  14  will be available only through passageway  26  and valve  80 .  
      The valve  80  will preferably be a one-way valve, meaning that when the valve is in an open state fluid will be permitted to flow in one direction only. For example, the one-way valve could be configured to permit access or fluid flow from the bag interior  14  out of the bag to outside  28 , and to block fluid passing from the outside  28  to the bag interior  14 . This type of valve would be useful for removing air from a bag used to store food or other perishable contents, for example. Alternatively, the one-way valve could be configured to permit access or fluid to flow in the other direction only, from the outside  28  of the bag into the bag interior  14 , and to block fluid from passing from the bag interior  14  to the outside  28 . This type of valve would be useful for an application in which it is desired to inject into the bag a special gas or liquid that preserves or protects the bag contents, such as for example, using formaldehyde to preserve a biological specimen.  
      The bag  10  of the present invention comprehends the use of almost any type of valve  80  to achieve a desired flow characteristic through the passageway  26 . For example, the valve  80  could be a two-way type instead of one-way. A two-way valve is a valve having two open states, in which one state permits flow in one direction and the other state permits fluid flow in the other direction. Activation of a particular state might arise simply from use of the valve. For example, squeezing the bag  10  might force air out of the bag interior  14 , through the valve  80  towards the outside  28  of the bag. Alternatively, a tube could be coupled to the passageway  26  containing the same valve and pressure applied to force a liquid into the bag. In this state, the valve would permit fluid flow in the opposite direction from the first use, from the outside  28  to the bag interior  14 . Alternatively, the two-way valve  80  could be configured so that the permitted direction of flow is set through a switch on the valve itself, or preferably, on the surface of the slider  20 .  
      The valve  80  may be configured so that when it is in an open state the passageway  26  will be substantially or completely open, so that fluid passing through the passageway will be able to flow at an optimum high rate. Alternatively, the valve  80  may be configured to partially close the passageway  26  to any degree desired.  
      It can be appreciated that valves are generally configured for installation in a passageway or tube located inside a solid body. Therefore, many types of standard valves are similiarly amenable for installation in the passageway  26  of the present invention, since the passageway  26  is preferably located inside the solid body of the slider  20 . A common type of valve suitable for use in the passageway  26  of the present invention is a ball valve, which is generally represented as valve  80  in  FIG. 5 . As pressure is applied to a ball valve, such as by suction through conduit  74 , the ball will rise and open the passageway  26 . Another type of valve  80  may be a pinching valve, which would provide access through the passageway upon squeezing or pinching the slider. Similarly, many other types of valves common in industrial and consumer applications may also be used in the present invention. In addition to a ball valve or pinching valve, the valve  80  may be a flapper valve, air valve, or check valve, for example.  
      The present invention comprehends use of the slider  20  without an integral passageway  26 . It can be appreciated that since the slider  20  is configured to open and close the bag opening  16 , and to form an airtight seal when in a completely closed position, a bag  10  made with the slider  20  may be useful even without the passageway  26 . For example, the bag  10  could be filled with a liquid and the slider closed to form an airtight seal, preventing leakage of the liquid. When the liquid contents are to be used, the slider could be pushed open slightly and the liquid poured out. Such a bag  10  would have the advantage of being easy to open and close, due to the slider  20 , and also provide the benefit of an airtight seal to better preserve perishable contents or hold liquids.  
      The present invention also comprehends separating the passageway  26  from the slider  20 . Such an arrangement is preferably realized using an access element  82  to contain or integrate with the passageway  26 . The access element  82  is generally a body positioned between two edges or panes of the bag  10 , and that contains the passageway  26  and valve  80 . The access element  82  may be sized and shaped similar to slider  20 , or it may have any other size and shape as long as it can be positioned between two edges of the bag  10 . The access element  82  is preferably fixed in position. This may be accomplished, for example, by sealing the panes  30  and  32  around the sides of the access element  82 .  
      In one embodiment, the two edges of the bag  10  may be two edges of opposed panels  30  and  32  that define bag opening  16 . In that case, the sides of access element  82  could be sealed between opposing panes  30  and  32  in a variety of ways known in the art. The bag  10  might also be made without interlocking features  18  around access element  82 , since the features  18  would not be needed to support slider movement in that portion of bag opening  16 . This embodiment is illustrated in  FIG. 11 , which shows the movable slider  20  without passageway  26 , and the access element  82  having the passageway  26  and a removable tube or straw  74 .  
      It can be appreciated that where the access element  82  is fixed, the use of the passageway  26  to access the bag interior  14  will not be affected by the particular positioning of access element  82  in the bag  10 . Accordingly, in a further embodiment the two edges of bag  10  could be two edges of opposed panels  30  and  32  that do not define bag opening  16 . This would generally comprise the perimeter of the bag  10  other than that portion occupied by bag opening  16 . In  FIG. 11 , for example, the two edges between which access element  82  could be placed could be the edges of panels  30  and  32  along closed sides  84  and  86  of bag  10 .  
      In this embodiment it is preferable that access element  82  be located between opposing panes or edges of the bag  10  that are joined, welded, or seamed together. Such an arrangement simplifies manufacturing of the bag  10 , since the access element  82  could be placed between the panels, which would wrap around the access element. The panels would be welded or sealed together as before, with the access element  82  sealed between them. Where the two opposing panels are joined by a fold, installation of the access element would be less convenient since a hole would need to be made. For example, if the bag  10  in  FIG. 11  were formed from a single panel folded along bottom side  88 , it would be less convenient to install the access element on side  88 . If the bag were formed from separate panels  30  and  32  that were welded or joined together along all edges, then it would be equally convenient to install the access element  82  along any of sides  84 ,  86 , or  88 .  
      The preferred embodiment of the present invention can now be understood as the case where access element  82  is the slider  20 . This embodiment is preferred since a bag having only one body, comprising a slider with an integrated passageway, is generally less costly and more efficient to produce and use than a bag having two bodies comprising an access element and slider.  
      A common type of bag production involves joining two rectangular panes along three sides, or along opposing sides of a single folded pane, leaving a bag opening  16  open on one side. A zipper having opposed interlocking features  18  can be separately produced and attached to the bag opening  16 . A slider may be inserted over the zipper in the bag opening  16  during production so that it is movable along the bag opening  16  without being removable from the bag itself. The standard production equipment also generally operates at a high cycle or production rate, which results in lower cost.  
      The bag portion  12  of the bag  10  of the present invention similarly can be made from one or two panes of plastic joined along two or three sides, leaving a bag opening  16 . The interlocking features  18  along the bag opening  16  can similarly be produced using standard production techniques, such as by attachment of a zipper, as described above. The slider  20  of the present invention is configured as an independent body capable of production by standard injection moulding techniques. Therefore, while the slider  20  is different from the prior art sliders in form and function, it can still be manufactured at a similar low cost. Moreover, the standard production equipment for producing bags and installing sliders can be used to produce the bags  10  of the present invention. In production, movable sliders  20  would be laid down in the bag opening  16 , and separate access elements  82  would be installed, if desired, either in the bag opening  16  or along a joint or seam between panes prior to the panes being sealed.  
      It can be appreciated therefore that the bag  10  of the present invention can be produced for about the same low cost or competitive with conventional slider bags that lack the other benefits of the present invention. The material costs for the bag and slider are similar to conventional bags, and the production equipment is the same or usable with only slight modification. Moreover, since standard production equipment may be used, the industry standard high cycle rates of such equipment may continue to be applicable. It can be further appreciated that this represents an improvement over the prior art. Since prior art devices generally require unconventional bags and valves, both the bag and valve materials and production equipment generally are non-standard and need to be custom made. Further, cycle rates are likely to be lower, which increases the cost of each bag.  
      In practice, the degree of airtightness provided by zippers or opposed interlocking features  18  will vary. An embodiment of a reclosable bag  10  having improved airtightness characteristics, particularly when used with lesser quality zippers, is shown in a top view in  FIG. 14 .  FIG. 15  is another top view, showing the bag  10  with an object  98  and a vacuum condition inside the bag interior  14 .  
      As shown in the figures, at the top of the bag  10  there is a bag opening  16  having an openable closure or opposed interlocking features  18 , configured and positioned to open and close the bag opening. A movable slider  20  is not shown along bag opening  16 , but may be included if desired. Also shown is an access element  82  fixed in position along the side  84  of the bag. The access element includes a passageway  26 , valve  80 , and fluid transmission conduit  74 . When the bag opening  16  is closed, access to the bag interior  14  is provided by access element  82 , or more particularly, by passageway  26  and valve  80  of access element  82 . The access element  82  is accordingly configured and positioned to permit air to be removed from the bag interior, through the passageway and valve, so as to create a negative pressure or vacuum in the bag interior relative to an exterior of the bag.  
      The bag  10 , and corresponding bag interior  14 , include two sections: an air-flow or ribbed section  92 , and a sealing or flat section  94 . The air-flow section  92  is generally configured to permit air flow through the air-flow section.  
      The air-flow section  92  is defined by opposing panes  30  and  32  that are sized and shaped so that when the panes are in contact, at least one channel or conduit is available inside bag interior  14  to permit air to flow through the interior of section  92 . As shown in  FIG. 14 , this may be achieved by including, in at least one of the panes, a surface defining one or more raised ribs  96 . The ribs  96  create channels or conduits, generally shown by arrows in  FIG. 14 , that enable air or gas to flow throughout the ribbed section  92 , along both the length and width of the section.  
      The air-flow section  92  is preferably constructed from a flat pane and an opposing ribbed pane, however two opposing ribbed panes may also be used. It can also be appreciated that three or more panes may also be used, as long as the function of providing air flow in the section  92  is maintained. The opposing panes may be any shape, but are preferably rectangular in accordance with common bag configurations. As shown in  FIG. 14 , the rectangular panes are preferably closed or joined along three sides to define the bottom  88  and parts of sides  84  and  86  of the bag  10 . The fourth or top side is preferably open and may be designated as an air access interface  93 , since it is the side through which air flows in and out of the air-flow section  92 . The air access interface  93  is accordingly positioned between the air-flow section  92  and the sealing section  94 , and is configured to permit fluid communication therebetween.  
      The sealing or flat section  94  is positioned between the closure and the air-flow section, and is generally configured such that, when there is negative pressure in bag interior  14  and the closure is closed, air is blocked from leaking from the outside or exterior of the bag through the closure and sealing section to the air-flow section. The sealing section generally comprises at least two opposing panes  30  and  32  that are sized and shaped so that when the panes are in contact, passage of air through the sealing section is blocked. Each of the panes in this section preferably have a flat or smooth surface. The opposing panes may be any shape, but again are preferably rectangular. The rectangular panes are preferably closed or joined on two sides to partly define sides  84  and  86  of bag  10 , and open on the other two opposing sides. One of the open sides preferably attaches to the air access interface  93 , to join and enable fluid communication between section  94  and air-flow section  92 , and the other open side defines bag opening  16 .  
      The access element  82  is preferably positioned in the sealing section  94  between the panes on one of the closed sides  84  and  86 . The access element  82  is preferably adjacent to the air access interface  93 , and most preferably within one-half inch of the air access interface  93 . In this way, there is fluid communication between the passageway and valve of the access element  82  and the air-flow section, through the sealing section. Suction that is applied through passageway  26  and valve  80  will be largely transmitted to air-flow section  92 , and not be unduly reduced due to the sealing or blocking effect of sealing section  94 . The access element  82  may also be positioned between the panes on one of the closed sides  84  and  86 , or the bottom  88 , of the air-flow section  92 . This configuration however is less preferred because of the risk of contamination of the access element  82  from the contents of the air-flow section.  
      As shown by the symbol “L” in  FIG. 14 , the sealing section  94  has a length which comprises the minimum distance between the closure and the air-flow section. Upon closing bag opening  16  and removing by suction the gas or air from the bag interior  14 , including from flat section  94 , the opposing panes of flat section  94  will generally stick or seal together. There will also be a tendency for ambient air outside the bag to attempt to penetrate or seep back into the bag  10  through bag opening  16  due to the negative pressure created by the vacuum in the interior of the bag. The degree to which ambient air enters the bag depends on the quality of the zipper or opposed interlocking features  18 . The additional sealing provided by the sealing section  94  will therefore improve the overall airtightness of the bag  10 , in comparison to the airtightness provided by the zipper  18  alone. Accordingly, the length of the sealing section  94  is selected to prevent air flow from the exterior of the bag through the closure and sealing section to the air-flow section, when the closure is closed and the bag interior has a negative air pressure. Since the strength of the seal increases with the length of “L”, a longer length will be preferred for bags having a corresponding lower quality zipper  18 .  
      In particular, it has been found that for better quality or more airtight zippers, a sealing section length of at least 1⅛ inches produces substantially better airtightness results. For generally lower quality or less airtight zippers  18 , a sealing section length of at least 3¼ inches produces substantially better airtightness results. Bags having lengths “L” within this range, of at least 1¼ inches, 1½ inches, 1¾ inches, 2 inches, 2¼ inches, 2½ inches, 2¾ inches, and 3 inches are also preferred.  
      The bag  10  of  FIG. 14  may be constructed using standard production techniques. In particular, the flat section  94  can be attached to the ribbed section  92  at the air access interface  93  using heat welding or other techniques used in the industry. Similarly, the zipper or opposed interlocking features  18  in the bag opening  16  may be heat welded to the opposing open end of the flat section  94 .  
      In an alternative embodiment, the zipper  18  may further include an extended portion that comprises, or integrally includes, the sealing section  94 . Generally the zipper  18  is a plastic element produced by an extrusion process. Accordingly, the extrusion process may be modified so that the bottom portion of the zipper  18  extends the full length of the sealing section  94 . The extended portion will most preferably be at least 1⅛ inches in length, but may also preferably be at least 1¼ inches, 1½ inches, 1¾ inches, 2 inches, 2¼ inches, 2½ inches, 2¾ inches, 3 inches, and 3¼ inches in length. In this embodiment of the bag  10 , while the zipper  18  element will be more costly, production of the bag  10  would be simplified since a connection or weld would no longer be required between the zipper and sealing section  94 .  
      The operation of the present invention can now be described, using as an example the reclosable bag  10  configured as a household storage bag as shown in  FIG. 10 . The user will likely begin use by moving the slider  20  to end  22 , to open bag opening  16 . The user will deposit a perishable food item  90  into the bag interior  14 , and then close the bag by moving slider  20  to the closed or sealed position at end  24 . Where the slider  20  uses detents  68 ,  70  as in  FIGS. 1 and 2 , the user will be able to gauge how far to move the slider by sensing or hearing the detents click or snap into position, thereby engaging the slider at the second end  24 . Alternatively, where the slider incorporates latch  72  as shown in  FIG. 10 , the user will lock the slider in place by rotating the latch to a down position and snapping it in place.  
      At this point the bag will be sealed airtight, but may contain residual air in the bag interior  14 . The user can then exchange air or fluid between the bag interior  14  and the outside  28  of the bag through the passageway  26  in the recloseable bag opening  16 . The removal of air or fluid from the bag interior  14  may be achieved, for example, by inserting the insertion end  76  of the hollow tube  74  into the passageway  26  and applying suction to the free end  78 . In a consumer application, the hollow tube  74  will preferably be a straw and the suction applied by the user&#39;s mouth. The valve  80  in this example will preferably be a one-way valve permitting fluid to flow in the direction from the bag interior  14  to the outside  28 . Upon removal of all or substantially all of the air in the bag interior  14 , the tube  74  may be removed from the passageway  26 , and the bag  10  placed in storage. In another embodiment, instead of using a hollow tube  74 , the bag  10  may be squeezed to force residual air out of the bag interior  14  through passageway  26 . This method could also be performed with the embodiment shown in  FIG. 11  having a slider and access element  82 .  
      It can be appreciated that the method of closing a bag of the present invention represents an improvement over the prior art. In the prior art the user would ordinarily close the slider close to end  24 , leaving a small opening  17 . The bag would be squeezed to force residual air out through opening  17 . Then, the user would close the slider with one hand while usually keeping the other hand pressed against the bag, to prevent the inflow of air during the period that the slider is being closed. Further, once the bag is closed, there is unlikely to be an airtight seal due to the presence of the separator or finger of the conventional slider in the bag opening. By contrast, in the present invention the user can force air out of the bag, by squeezing the bag, applying suction to hollow tube  74 , or otherwise, and not be concerned about the possible inflow of air because any such air will be blocked by the valve  80 . It can accordingly be appreciated that the method of closing a bag of the present invention is easier and more convenient than the conventional method, and further produces a more air free bag interior  14 .  
      In another application of the present invention, the passageway  26  could be fitted with a valve  80  that permits fluid flow into the bag interior  14 , while blocking flow in the opposite direction. Such a bag could be used in an industrial setting to receive a drinkable fluid or other fluid for commercial sale. For example, where the contents are a drinkable fluid the valve  80  could be made two-way, so the user could use a straw to retrieve the contents. Alternatively, a two body configuration as shown in  FIG. 11  may be used, where the slider  20  has a passageway  26  with a valve permitting fluid flow in one direction, and the access element  82  has a passageway  26  with a valve permitting fluid flow in the other direction. In that case, one passageway would be used to fill the bag, and the other used to remove or drink the contents. For a non-drinkable type of fluid, the slider may be pushed open a short distance to permit the user to pour out the contents.  
      It can be appreciated that a variety of commercial bag configurations are made possible by the present invention. In particular, the parameters available to a designer of a bag  10  of the present invention include: the choice of which edges  48  and  50  to use for the slider, whether to use a single slider  20  or an additional access element  82  with one or two passageways between them, selection of the type of valve  80 , and also whether to seal all or a portion of interlocking features  18 . In addition, the designer can select a variety of bag shapes in addition to the standard two pane configuration.  
      For example,  FIGS. 12 and 13  show embodiments of bags  10  suitable for use as commercial drink containers.  FIG. 12  is a round container and  FIG. 13  is a rectangular container having gussets on either end. The round container has the advantage of being inexpensive, providing optimally large internal volume for the amount of material used, and also optimizing shipping capacity because adjacent bags will compress against each other to leave very little unused space.  
      The bag portions  12  may be produced using standard equipment for the types of bags shown in  FIGS. 12 and 13 . The bag opening  16  may be formed from a slit or cut in the bag surface, and the slider  20  installed using standard equipment. In a variation on the embodiments shown, the bag opening  16  could be made much shorter, or most of the length of the bag opening  16  could be sealed. The slider could be movable along a short distance, perhaps a distance approximately equal to its length. In production, the slider could be positioned to leave a small opening  17 , and a nozzle inserted into opening  17  to fill the containers. The slider could then be moved a short distance to seal the opening, and remain in this position after sale. User access could be through a straw inserted into the passageways  26 .  
      An issue that could arise with a commercial drink package that is made from a soft material or used by children, for example, is inadvertent squirting of the contents upon pressure being applied to the sides of the bags. In the bags of  FIGS. 12 and 13  it can be appreciated that the valves  80  used would preferably be configured to permit fluid flow out of the bag interior  14 . Such valves could be further configured to maintain a closed state up to a predetermined threshold of pressure. This pressure level could be set, for example, to be higher than that ordinarily experienced by a casual squeezing of the bag. Preferably, the pressure threshold could be set to require a minimum degree of suction, either alone or in combination with some squeezing of the sides of the bag. In this way, inadvertent squirting of the bag contents could be reduced or avoided. Further, the passageway can be sized to permit only a limited amount of flow to prevent a sudden splurge of liquid.  
      In yet another embodiment, a bag  10  could be made with a slider having two joining edges  48 . The bag opening  16  would then always be closed on both sides of the slider  20 . In a further variation, the slider could have the passageway  26  without a valve  80 , so that the passageway is always open. The panes  30  and  32  could be sealed together below the slider  20  at every point except a small portion. Therefore, the bag  10  would be sealed for every position of the slider  20  except where the slider is positioned so that the passageway  26  is immediately above the open portion. The positioning of the slider would function as a valve in this embodiment, to open or close the passageway. In production the slider could be positioned first over the open portion to receive a nozzle into the passageway, to fill the bag with a drinkable fluid, for example. The slider could then be pushed to a side, to seal the contents during transport and storage. Upon purchase, the consumer would move the slider to the access position and insert a straw to drink the contents.  
      It will be appreciated by those skilled in the art that the foregoing description was in respect of preferred embodiments and that various alterations and modifications are possible within the broad scope of the appended claims without departing from the spirit of the invention. For example, while reference is made to a bag having one or two bodies, more bodies may also be used in a single bag where the application merits. Various other modifications will be apparent to those skilled in the art but are not described in any further detail herein.