Patent Publication Number: US-7219819-B2

Title: Self-venting valve

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a self-venting valve for providing, and controlling the rate of, a smooth and continuous fluid flow. 
   It is known to provide molded plastic valves for dispensing liquid from containers, in particular disposable containers of the type popular for holding a liquid such as water, juice or detergent. One well known type of valve for this purpose is a so-called “rotary” valve. In this type of valve, a handle is rotatably actuated by a user to rotate a valve core within a valve housing that is attached to a container. Rotation of the core aligns an aperture in the core with an aperture in the housing to provide a passageway that allows liquid to flow from the container. 
   An alternative to the rotary valve is a so-called “push button” valve. This type has a resilient plastic valve diaphragm which, when pressed by a user, opens an aperture provided in the valve housing to allow liquid to flow from the container. The resilient plastic diaphragm, commonly referred to as a “push button”, can be arranged so that it positively seals the aperture when manual pressure is removed, thus providing for a self-closing valve. Tap valves of this type require the user to provide manual pressure to the push button throughout the liquid dispensing process, which can be inconvenient when dispensing large quantities of a liquid, particularly when one of the user&#39;s hands is needed to hold a receptacle, such as a drinking glass, leaving only one hand to actuate the push button. 
   Effective metering of the flow rate is generally more difficult to achieve with push button valves than it is with rotary valves. In practice, push button valves provide substantially only “ON/OFF” operation. 
   Also, there are known slide valves that require a user to push or pull a part of the valve in a certain direction to actuate the valve, but actuation of such a valve may cause the container to unintentionally slide in that direction. If, as is commonly the case, that direction is toward the user, the container could be pulled off the surface it is resting on, unless one hand is used to restrain the container. However, the user&#39;s second hand normally would be occupied holding the drinking glass or other receptacle. 
   Regardless of the valve type used, when a liquid is dispensed through an aperture in a container and valve, ambient pressure above the liquid level in the container drops and creates a partial vacuum. This vacuum must be filled by a volume of fluid—generally air—equal to the volume of liquid that has been removed to equalize the pressure within the container. In early containers, the pressure was equalized by external air drawn into the container through the same valve aperture through which the liquid exited the container. However, in such an arrangement, the external air attempting to enter the container would disrupt the outflow of liquid attempting to exit the container, thereby causing discontinuous liquid flow (i.e., “glugging”) and reducing the outflow rate. 
   It is known that continuous and smooth liquid flow can be achieved using containers that are capable of collapsing as liquid flows therefrom or using containers that are vented, because these types of containers are able to decrease the magnitude of the partial vacuum created above the liquid level inside the container without requiring air to flow into the container through the valve. However, a collapsible container, such as a balloon or bag, for example, may be easily damaged and may not be easily attached to a valve. A vented container may allow the contents to be spoiled by substantially continuous exposure to air and to be spilled from the vent. These problems can be addressed by providing a vent that is sealed until opened by the user (e.g., by puncturing), but once the vent is unsealed, spillage and spoilage become possible. A reclosable vent can be provided, but users are unlikely to bother reclosing the vent. 
   Accordingly, it would be advantageous to be able to provide a container with a valve that provides a smooth and continuous outflow of liquid therefrom by maintaining neutral atmospheric pressure within the container while dispensing the liquid, even when the container is unvented or substantially rigid, and that allows the liquid outflow rate to be varied. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to provide a container with a valve that provides a smooth and continuous outflow of liquid therefrom by maintaining neutral atmospheric pressure within the container while dispensing the liquid, even when the container is unvented or substantially rigid. 
   It is also an object of this invention to provide such a valve that allows the liquid outflow rate to be varied. 
   In accordance with the present invention, there is provided a container with a valve assembly for providing to a user continuous liquid flow. The container has an orifice in a side-wall, and the orifice has a valve attachment to which the valve assembly is attached in communication with the orifice. The valve assembly comprises a valve housing that includes a housing body portion. The housing body portion has an air-back aperture and a liquid-out aperture in a first side facing the orifice, a spout in a second side facing away from the orifice, and a substantially hollow interior between the first side and the second side. The valve housing also includes a housing attachment that extends from the air-back aperture and the liquid-out aperture on the first side and that attaches the housing body portion to the valve attachment. The valve assembly also comprises a valve core that includes a core body. The core body has a liquid-out passageway and an air-back passageway and moves within the hollow interior to register the liquid-out passageway with the liquid-out aperture and the spout to control liquid flow through the liquid-out passageway, and to register the air-back passageway with the air-back aperture and the spout to control fluid flow through the air-back passageway between the air-back aperture and the spout. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other advantages of the invention will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
       FIG. 1  is a front elevational view of a preferred embodiment of a valve housing according to the present invention; 
       FIG. 2  is a side elevational view of the valve housing of  FIG. 1 , taken from line  2 — 2  of  FIG. 1 ; 
       FIG. 3A  is a rear elevational view of the valve housing of  FIGS. 1 and 2 , taken from line  3 A— 3 A of  FIG. 2 , but with most of the fitment omitted; 
       FIGS. 3B and 3C  are vertical cross-sectional views of the valve housing of  FIGS. 1–3A , taken from line  3 B of  FIG. 1 , cooperating with a container; 
       FIG. 4  is a side elevational view of a preferred embodiment of a valve core according to the present invention; 
       FIG. 5  is an elevational view of the valve core of  FIG. 4 , taken from line  5 — 5  of  FIG. 4 ; 
       FIG. 6  is an elevational view of the valve core of  FIGS. 4 and 5 , taken from line  6 — 6  of  FIG. 5 ; 
       FIG. 7  is an elevational view of the valve core of  FIGS. 4–6 , taken from line  7 — 7  of  FIG. 6 ; 
       FIG. 8  is an end view of the valve core of  FIGS. 4–7 , taken from line  8 — 8  of  FIG. 7 ; 
       FIGS. 9–14  are side views of an assembled valve of the present invention in various stages of actuation; 
       FIG. 15  is a front elevational view of the valve assembly of  FIGS. 9–14 , in the stage of actuation represented by  FIG. 9 , taken from line  15 — 15  of  FIG. 9 ; 
       FIG. 16  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–15 , taken from line  16 — 16  of  FIG. 15 ; 
       FIG. 17  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–16 , taken from line  17 — 17  of  FIG. 15 ; 
       FIG. 18  is a rear elevational view of the valve assembly of  FIGS. 9–17 , taken from line  18 — 18  of  FIG. 16 , but with most of the fitment element omitted; 
       FIG. 19  is a front elevational view of the valve assembly of  FIGS. 9–18 , similar to  FIG. 15 , but in the stage of actuation represented by  FIG. 10 , taken from line  19 — 19  of  FIG. 10 ; 
       FIG. 20  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–19 , taken from line  20 — 20  of  FIG. 19 ; 
       FIG. 21  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–20 , taken from line  21 — 21  of  FIG. 19 ; 
       FIG. 22  is a rear elevational view of the valve assembly of  FIGS. 9–21 , taken from line  22 — 22  of  FIG. 20 , but with most of the fitment element omitted; 
       FIG. 23  is a front elevational view of the valve assembly of  FIGS. 9–22 , similar to  FIGS. 15 and 19 , but in the stage of actuation represented by  FIG. 11 , taken from line  23 — 23  of  FIG. 11 ; 
       FIG. 24  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–23 , taken from line  24 — 24  of  FIG. 23 ; 
       FIG. 25  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–24 , taken from line  25 — 25  of  FIG. 23 ; 
       FIG. 26  is a rear elevational view of the valve assembly of  FIGS. 9–25 , taken from line  26 — 26  of  FIG. 24 , but with most of the fitment element omitted; 
       FIG. 27  is a front elevational view of the valve assembly of  FIGS. 9–26 , similar to  FIGS. 15 ,  19 , and  23 , but in the stage of actuation represented by  FIG. 12 , taken from line  27 — 27  of  FIG. 12 ; 
       FIG. 28  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–27 , taken from line  28 — 28  of  FIG. 27 ; 
       FIG. 29  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–28 , taken from line  29 — 29  of  FIG. 27 ; 
       FIG. 30  is a rear elevational view of the valve assembly of  FIGS. 9–29 , taken from line  30 — 30  of  FIG. 28 , but with most of the fitment element omitted; 
       FIG. 31  is a front elevational view of the valve assembly of  FIGS. 9–30 , similar to  FIGS. 15 ,  19 ,  23 , and  27 , but in the stage of actuation represented by  FIG. 13 , taken from line  31 — 31  of  FIG. 13 ; 
       FIG. 32  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–31 , taken from line  32 — 32  of  FIG. 31 ; 
       FIG. 33  is a vertical cross-sectional view of the valve assembly of  FIGS. 9–32 , taken from line  33 — 33  of  FIG. 31 ; 
       FIG. 34  is a rear elevational view of the valve assembly of  FIGS. 9–33 , taken from line  34 — 34  of  FIG. 32 , but with most of the fitment element omitted; 
       FIG. 35  is a partially sectional perspective view of the valve assembly of  FIGS. 9–34 , taken from line  35 — 35  of  FIG. 31 ; 
       FIG. 36  is a partially sectional perspective view of the valve assembly of  FIGS. 9–35 , taken from line  36 — 36  of  FIG. 31 ; 
       FIG. 37  is a partially sectional perspective view of the valve assembly of  FIGS. 9–36 , taken from line  37 — 37  of  FIG. 31 ; 
       FIG. 38  is a side elevational view of a second embodiment of a valve core according to the present invention; 
       FIG. 39  is a side elevational view of the valve core of  FIG. 38 , taken from line  39 — 39  of  FIG. 38 ; 
       FIG. 40  is a side elevational view of the valve core of  FIGS. 38 and 39 , taken from line  40 — 40  of  FIG. 39 ; 
       FIG. 41  is a side elevational view of the valve core of  FIGS. 38–40 , taken from line  41 — 41  of  FIG. 40 ; 
       FIG. 42  is a front elevational view, similar to  FIG. 15 , of a second embodiment of a valve assembly according to the present invention, incorporating the core of  FIGS. 38–41 , in the stage of actuation represented by  FIG. 9 , taken from line  42 — 42  of  FIG. 9 ; 
       FIG. 43  is a vertical cross-sectional view of the valve assembly of  FIG. 42 , taken from line  43 — 43  of  FIG. 42 ; 
       FIG. 44  is a vertical cross-sectional view of the valve assembly of  FIGS. 42 and 43 , taken from line  44 — 44  of  FIG. 42 ; 
       FIG. 45  is a rear elevational view of the valve assembly of  FIGS. 42–44 , taken from line  45 — 45  of  FIG. 43 , but with most of the fitment element omitted; 
       FIG. 46  is a front elevational view of the valve assembly of  FIGS. 42–45 , similar to  FIG. 42 , but in the stage of actuation represented by  FIG. 13 , taken from line  46 — 46  of  FIG. 13 ; 
       FIG. 47  is a vertical cross-sectional view of the valve assembly of  FIGS. 42–46 , taken from line  47 — 47  of  FIG. 46 ; 
       FIG. 48  is a vertical cross-sectional view of the valve assembly of  FIGS. 43–47 , taken from line  48 — 48  of  FIG. 46 ; 
       FIG. 49  is a rear elevational view of the valve assembly of  FIGS. 42–48 , taken from line  49 — 49  of  FIG. 47 , but with most of the fitment element omitted; 
       FIG. 50  is a side elevational view of a third embodiment of a valve core according to the present invention; 
       FIG. 51  is a side elevational view of the valve core of  FIG. 50 , taken from line  51 — 51  of  FIG. 50 ; 
       FIG. 52  is a side elevational view of the valve core of  FIGS. 50 and 51 , taken from line  52 — 52  of  FIG. 51 ; 
       FIG. 53  is a side elevational view of the valve core of  FIGS. 50–52 , taken from line  53 — 53  of  FIG. 52 ; 
       FIG. 54  is a front elevational view, similar to  FIG. 15 , of a third embodiment of a valve assembly according to the present invention, incorporating the core of  FIGS. 50–53 , in the stage of actuation represented by  FIG. 9 , taken from line  54 — 54  of  FIG. 9 ; 
       FIG. 55  is a vertical cross-sectional view of the valve assembly of  FIG. 54 , taken from line  55 — 55  of  FIG. 54 ; 
       FIG. 56  is a vertical cross-sectional view of the valve assembly of  FIGS. 54 and 55 , taken from line  55 — 55  of  FIG. 54 ; 
       FIG. 57  is a rear elevational view of the valve assembly of  FIGS. 54–56 , taken from line  57 — 57  of  FIG. 55 , but with most of the fitment element omitted; 
       FIG. 58  is a front elevational view of the valve assembly of  FIGS. 54–57 , similar to  FIG. 54 , but in the stage of actuation represented by  FIG. 13 , taken from line  58 — 58  of  FIG. 13 ; 
       FIG. 59  is a vertical cross-sectional view of the valve assembly of  FIGS. 54–58 , taken from line  59 — 59  of  FIG. 58 ; 
       FIG. 60  is a vertical cross-sectional view of the valve assembly of  FIGS. 54–59 , taken from line  60 — 60  of  FIG. 58 ; 
       FIG. 61  is a rear elevational view of the valve assembly of  FIGS. 54–60 , taken from line  61 — 61  of  FIG. 59 , but with most of the fitment element omitted; 
       FIG. 62  is a front elevational view of a second embodiment of a valve housing according to the present invention; 
       FIG. 63  is a side elevational view of the valve housing of  FIG. 62 , taken from line  63 — 63  of  FIG. 62 ; 
       FIG. 64  is a rear elevational view of the valve housing of  FIGS. 62 and 63 , taken from line  64 — 64  of  FIG. 63 , but with most of the fitment element omitted; 
       FIG. 65  is a top elevational view of the valve housing of  FIGS. 62–64 , taken from line  65 — 65  of  FIG. 64 ; 
       FIG. 66  is a front elevational view of a fourth embodiment of a valve core according to the present invention; 
       FIG. 67  is an end view of the valve core of  FIG. 66 , taken from line  67 — 67  of  FIG. 66 ; 
       FIG. 68  is a rear elevational view of the valve core of  FIGS. 66 and 67 , taken from line  68 — 68  of  FIG. 67 ; 
       FIGS. 69–71  are front elevational views of an assembled valve of the present invention, incorporating the housing of  FIGS. 62–65  and the core of  FIGS. 66–68 , in different stages of actuation, but with a portion of the fitment element omitted; 
       FIG. 72  is a vertical cross-sectional view of the valve assembly of  FIGS. 69–71 , taken from line  72 — 72  of  FIG. 69 ; 
       FIG. 73  is a vertical cross-sectional view of the valve assembly of  FIGS. 69–72 , taken from line  73 — 73  of  FIG. 69 ; 
       FIG. 74  is a vertical cross-sectional view of the valve assembly of  FIGS. 69–73 , taken from line  74 — 74  of  FIG. 70 ; 
       FIG. 75  is a vertical cross-sectional view of the valve assembly of  FIGS. 69–74 , taken from line  75 — 75  of  FIG. 71 ; 
       FIG. 76  is a vertical cross-sectional view of the valve assembly of  FIGS. 69–75 , taken from line  76 — 76  of  FIG. 71 ; 
       FIG. 77  is a rear elevational view of a dust cover according to the present invention; and 
       FIG. 78  is a partially sectional side view of the dust cover of  FIG. 77 , taken from line  78 — 78  of  FIG. 77 , cooperating with the valve assembly of  FIG. 9 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention provides dispensing of a smooth and continuous flow of liquid from a rigid or unvented container through a valve assembly having a housing attached to the container, and a core that is movable, and particularly rotatable, within the housing to provide both a liquid-out passageway and an at least partially separate air-return passageway between the container and the ambient atmosphere. Preferably, the core has a handle or actuator that is rotatable by one hand of a user. Also preferably, the housing and core cooperate to allow metering of the liquid outflow rate. The user, preferably, can let go of the actuator once the desired liquid outflow rate is achieved and the valve assembly will remain in that position to dispense liquid until closed by the user. 
   Because an air-back passageway is at least in part formed separately from the liquid-out passageway, air can flow into the container simultaneously with the dispensing of liquid therefrom. Thus, the pressure can continuously be equalized between the exterior of the container and the interior of the container above the liquid level, so that the liquid will flow smoothly and at a controllable rate dictated by the relative position of the housing and the core, without requiring venting or the provision of a collapsible container. 
   In accordance with the invention, the valve housing preferably has a hollow interior, an air-back aperture, a liquid-out aperture, a spout, and an attachment that may attach to a container. The valve core preferably has a handle or actuator attached thereto for moving the core relative to the housing to control both the size of the air-back passageway preferably provided between the air-back aperture and the spout, and the size of the liquid-out passageway preferably provided between the liquid-out aperture and the spout. The air-back aperture and the liquid-out aperture may be generally adjacent one another, but the air-back aperture should be at least partially above the liquid-out aperture, so that the liquid pressure at the container end of the air-back passageway is less than that at the container end of the liquid-out passageway. This pressure differential may be enhanced by extending an extension tube within the container upward from the air-back aperture into the container. 
   As stated above, the core is preferably rotated, but other types of movement can be used. For example, the core may translate or slide. Alternatively, a combination of movements can be used. For example, the core could primarily rotate, but there could be a translational component to the movement as well. As the core is moved, the degree of registration of each respective passageway with the spout and with its corresponding aperture preferably changes. Upon initial actuation of the actuator or handle to move the core, liquid will begin to flow from the full or previously unopened container, through both passageways, to the spout as the passageways begin to register with the apertures. As liquid flows out of the container, the ambient pressure above the liquid level inside the container will drop, thereby creating a partial vacuum. 
   As the ambient pressure above the liquid level inside the container drops below the external ambient pressure, the partial vacuum thereby created preferably draws air into the container through the air-back passageway, displacing the liquid already in that passageway. Air preferably will enter the air-back passageway, and not the liquid-out passageway, because of the aforementioned lower pressure at the container end of the air-back passageway. Also, this passageway is preferably made narrower than the liquid-out passageway so that the amount of liquid to be displaced by air in the air-back passageway is less than that in the liquid-out passageway. This also will favor establishment of the air-back flow in this passageway. The relative sizes of the passageways preferably depend upon various factors including the range of desired rate of liquid flow from the container, the viscosity of the liquid, and the relative heights of the air-back aperture and liquid-out aperture in the container, etc. 
   Once air begins to flow into the container, this effect preferably is self-sustaining throughout further actuation of the core in both the opening and closing directions of the valve, until the valve is completely closed, as long as a partial vacuum exists above the liquid level. Preferably, the seal between the valve assembly and the container and the seal between the valve housing and the valve core are sufficient to maintain a degree of partial vacuum inside the container when the valve is completely closed, so that the air-back effect is immediate upon reopening of the valve. If the vacuum is not maintained when the valve is closed, then the next time the valve is opened, operation will be similar to the initial time that the valve was opened. 
   In one embodiment, the liquid-out passageway is formed within a hollow interior of the core between two openings formed in the surface of the core, and the air-back passageway is formed about the core along a channel formed in the surface of the core. In a second embodiment, both the air-back passageway and the liquid-out passageway are formed about the core along respective channels formed into the surface of the core. In a third embodiment, both the air-back passageway and the liquid-out passageway are formed by respective passageways within the hollow interior of the core between respective pairs of openings formed in the surface of the core. 
   A tamper-evident seal preferably is provided. This seal preferably also acts as a dust cover to keep dust and debris out of the spout prior to initial use and between uses (if replaced by the user). Preferably, the seal also engages with the valve to prevent valve actuation when the seal is in place. 
   The invention will now be described with reference to  FIGS. 1–78 . 
     FIGS. 1–3C  show a preferred embodiment of a valve housing  12  and  FIGS. 4–8  show a preferred embodiment of a valve core  32  according to the present invention. 
   As seen in  FIGS. 1–3A , valve housing  12  preferably includes a hollow substantially cylindrical body portion  14  attached to a container fitment portion  16 , which preferably extends from periphery or surface section  18  of body portion  14  substantially perpendicularly to longitudinal axis A of body portion  14 . Preferably, two apertures—a liquid-out aperture  20  and an air-back aperture  22 —are formed through periphery  18  of body portion  14  to allow liquid and air to move between the hollow of body portion  14  and fitment portion  16 , although any larger number of apertures may be provided. 
   In a preferred embodiment, liquid-out aperture  20  is substantially rectangular, having a height H and a length L, and air-back aperture  22  is substantially circular, having a diameter d. In addition, a distance h substantially separates the top of aperture  20  from the top of aperture  22 , as shown, to provide a pressure difference between the container end of air-back aperture  22  and the container end of liquid-back aperture  20 . Instead of or in addition to a distance h separating the tops of the apertures, extension tube  23  (see  FIG. 3C ) preferably is provided to lower the pressure at the container end of air-back aperture  22  even more as compared to that at the container end of liquid-out aperture  20 , for reasons explained above. Opposite fitment portion  16 , a spout portion  24  preferably extends from body portion  14  for dispensing liquid from body portion  14  to a user and for supplying external air to body portion  14 . Preferably, spout  24  provides a substantially circular opening, having a diameter D. The shape and size of spout  24  may be chosen to substantially match the aperture of a variety of receptacles to be filled by the user. 
   Body portion  14  is shown extending along longitudinal axis A, from a preferably open end  26 , past spout portion  24  and apertures  20  and  22 , to a closed end  28 , although end  28  may conceivably be open, as long as a liquid tight seal can be formed at that end between body portion  14  and valve core  32  in the assembled valve. In a more particularly preferred embodiment, open end  26  includes an actuation stop  27  for limiting the actuation range of a valve core (described below). Housing  12  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, linear low-density polyethylene, or other polymer. 
   Fitment portion  16  preferably includes screw threads  30  to allow attachment of housing  12  to a threaded collar around an orifice in a side-wall of a liquid container (not shown). It will be appreciated that housing  12  may be attached to a container in other ways, such as with a snap-fitted collar, or by gluing or ultrasonic welding, etc. It should be noted that this attachment may be made at any angle relative to the bottom of the container (i.e., relative to the liquid level inside the container). 
   Each of  FIGS. 3B and 3C  shows a portion of valve housing  12  attached to a side-wall of a container. So that the liquid pressure at the container end of the air-back passageway is less than the liquid pressure at the container end of the liquid-out passageway, for reasons stated above, the height of the liquid level above the container end of air-back aperture  22  preferably should be less than that above the container end of liquid-out aperture  20 . In  FIG. 3B , side-wall ls forms right angle θ with bottom-wall  1   b  of container  1 , and the liquid level in container  1  is at height X above the top of liquid-out aperture  20 . In this embodiment, the liquid pressure at the container end of air-back aperture  22  is less than the liquid pressure at the container end of liquid-out aperture  20  because the height of the liquid level above aperture  20  exceeds the height of the liquid level above aperture  22  by distance h, as shown. 
   In  FIG. 3C , side-wall  1   s   1  forms oblique angle θ 1  with bottom-wall  1   b   1  of container  11 , and the liquid level in container  11  again is at height X above the top of liquid-out aperture  20 . In this embodiment, the liquid pressure at the container end of air-back aperture  22  is less than the liquid pressure at the container end of liquid-out aperture  20  because the height of the liquid level above aperture  20  exceeds the height of the liquid level above aperture  22  by a distance hsin θ 1 , as shown. 
   Without an extension tube, the difference between the liquid pressure at aperture  20  and the liquid pressure at aperture  22  will be less in the embodiment shown in  FIG. 3C  than in the embodiment shown in  FIG. 3B  because distance hsin θ 1  will always be less than distance h. However, when valve housing  12  is provided with an extension tube  23  having a length l, the difference between the liquid pressure at aperture  20  and the liquid pressure at aperture  22  in  FIG. 3C  increases because the difference between the height of the liquid level above aperture  22  and the height of the liquid level above aperture  20  increases by a distance l cos θ 1 , as shown. If extension tube  23  is provided, the tops of apertures  20  and  22  need not be separated by a distance h, because distance l cos θ 1  allows the liquid pressure at the container end of air-back aperture  22  to be less than the liquid pressure at the container end of liquid-out aperture  20 . Extension tube  23  may be integrally molded as part of valve housing  12  or it may be part of a separate assembly. The length and diameter of extension tube  23  may be chosen to provide the most user-friendly range of liquid outflow rates based upon the angle between the side-wall and bottom-wall of the container, the volume and rigidity of the container, and the liquid to be dispensed. Extension tube  23  does not affect the difference between the liquid pressure at aperture  20  and the liquid pressure at aperture  22  in  FIG. 3B . Therefore, in the configuration shown in  FIG. 3B , extension tube  23  would be of no use. However, extension tube  23  may be upwardly curved to affect the difference between the liquid pressure at aperture  20  and the liquid pressure at aperture  22  in  FIG. 3B . It should be noted that a higher extension tube allows more air flow up into the container, but only until the point where the inflow volume of air through the valve assembly matches the maximum outflow volume of liquid through the valve assembly. Furthermore, it should be noted that when the valve assembly is used with a collapsible container, such as a balloon or bag, for example, the magnitude of the partial vacuum created above the liquid level inside the container decreases, thereby reducing the need for air to be drawn into the container through the air-back passageway. 
   Preferably, and as shown in  FIGS. 1–3C , housing  12  includes top flanges  17  to provide the user with a grip in order to move the valve assembly and container in a refrigerator or on a counter, for example. If a handle is only provided on the top of the container, the lack of a grip area on the front of the container may sometimes force the user to use valve housing  12  as a handle in order to move the container. Flanges  17  preferably give the user&#39;s thumb a place to grip as his or her fingers wrap around the back and bottom of housing  12  to facilitate movement of the container. 
   As seen in  FIGS. 4–8 , valve core  32  preferably includes a substantially cylindrical and hollow valve core body  34  having a longitudinal axis Al (which when assembled with valve housing  12  preferably is substantially coincident with axis A of  FIGS. 1–3 ). There is also attached at one end a handle or actuator  36 , which preferably is substantially perpendicular to the longitudinal axis Al of core body  34 . Preferably, a liquid-out passageway  38  (see  FIGS. 16–37 ) is formed within core body  34 , between an exterior-facing opening  40  and a container-facing opening  42 , which are formed through the peripheral surface of core body  34 . In a preferred embodiment, exterior-facing opening  40  is substantially semicircular, having a diameter D 1 , and container-facing opening  42  is substantially rectangular, having a height H 1  and a length L 1 , as shown. An air channel  46  preferably is formed into the peripheral surface of core body  34  to form an air-back passageway  44  about core body  34  (see  FIGS. 17–37 ) when core  32  is assembled with housing  12  to form a valve assembly of the present invention. In a preferred embodiment, air channel  46  is formed into the surface of core body  34  to a depth t, and extends circumferentially about core body  34  from a first end j to a second end k. Preferably, channel  46  is wider at second end k than at first end j such that a portion of channel  46  at second end k extends away from handle  36  to at least a point Z along the length of core body  34 , for reasons to be explained below. 
   Core body  34  is shown to extend along longitudinal axis A 1 , from a preferably open end  33 , past openings  40  and  42 , and air channel  46 , to a closed end  35  shared by handle  36 , although end  33  may conceivably be closed in other embodiments. In a more particularly preferred embodiment, core  32  includes an actuation track  37 . Track  37  is formed into the periphery of handle  36  closest to end  35 , from a point F to a point E, for limiting the actuation range of core  32  within body portion  14  (described in more detail below). Like valve body portion  14 , valve core  32  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, linear low-density polyethylene, or other polymer, and preferably is of the same material as body portion  14 . It should be noted that core body  34  described above is only exemplary and need not be hollow, and that, in an other embodiment (not shown), core body  34  could be substantially solid and the passageways could be formed through and/or about the solid of the core body. 
     FIGS. 9–37  show how valve housing  12  of  FIGS. 1–3C  and valve core  32  of  FIGS. 4–8  may be combined to form valve assembly  10  of the present invention. Preferably, core body  34  creates a seal within the hollow of cylindrical body portion  14  and is rotatable about longitudinal axis A, which is shared by core body  34  and body portion  14 . Through rotation of handle  36  about axis A, and therefore through rotation of core body  34  within body portion  14 , the geometry of housing  12  and core  32  (described above) preferably regulates not only the flow of liquid from a container, through liquid-out aperture  20 , liquid-out passageway  38 , and spout  24  to the user, but also the supply of external air through spout  24 , air-back passageway  44 , and air-back aperture  22  to the interior of the container above the liquid level. Once a partial vacuum is created inside the container, this geometry also preferably provides a seal between the housing and the core that is sufficient to substantially maintain the partial vacuum inside the container after the valve is closed. Valve assembly  10  may provide the liquid and air-tight seal between the elements of housing  12  and core  32 , and between the container and its ambient environment, through the use of standard surface-to-surface interference fits or through the use of gaskets, such as molded seal beads around the ends of the core body and at the perimeter of each end of each passageway (not shown for the sake of clarity of the drawings), for example. 
     FIGS. 9–13  are end views of valve assembly  10  having core  32  rotated to five different positions, as indicated by the orientations of handle  36 .  FIG. 9  shows valve assembly  10  in a “closed” position. In this position, handle  36  is shown to have essentially a 0° actuation angle with respect to a vertical line V that is substantially perpendicular to axis A (not shown), (“vertical” being understood in the sense of  FIGS. 9–13 ; the actual angle will be a function of the incline of the surface of the container to which valve assembly  10  is attached (see  FIGS. 3B and 3C )). As seen by the orientation of handle  36  in  FIG. 9 , the interaction of actuation stop  27  with point F of actuation track  37  preferably prevents handle  36  from rotating beyond this position in direction C. 
     FIG. 10  shows valve assembly  10  in a “minimally ON” position, in which handle  36  has been rotated in direction W or C about axis A to an actuation angle α with respect to V.  FIG. 11  shows valve assembly  10  in a “halfway ON” position, in which handle  36  has been rotated in direction W or C about axis A to an actuation angle β with respect to V.  FIG. 12  shows valve assembly  10  in a “significantly ON” position, in which handle  36  has been rotated in direction W or C about axis A to an actuation angle γ with respect to V.  FIG. 13  shows valve assembly  10  in a “completely ON” position, in which handle  36  has been rotated in direction W about axis A to an actuation angle δ with respect to V. As seen in this drawing, the interaction between actuation stop  27  and point E of actuation track  37  preferably prevents handle  36  from rotating further in direction W, so that handle  36  may not rotate to an actuation angle that allows the handle to interfere with the receptacle that the user is filling with liquid, for example. 
   In a more preferred embodiment, shown in  FIG. 14 , the “closed” position may be defined by handle  36  forming an actuation angle greater than 0° (i.e., α 1 ) with respect to V. This may be desirable when the surface of the container closest to the valve assembly makes it difficult for a user to grasp a handle that is vertically aligned with the valve (see  FIG. 9 ). This may be accomplished easily by forming handle  36  and actuation track  37  at a different circumferential position (as compared to  FIG. 9 ) on valve core body  34 , and by forming actuation stop  27  at a correspondingly different position (as compared to  FIG. 9 ) on housing portion  14 , such that when actuation stop  27  contacts point F of track  37 , handle  36  forms the desired angle with respect to V. This feature allows the core to be grippable and actuatable in all positions that could be used while dispensing liquid. In yet another embodiment (not shown), it may be desirable for the “completely ON” position to be defined by handle  36  forming an actuation angle less than angle δ with respect to V, so that the handle is less likely to interfere with the receptacle being filled. This may be accomplished by forming handle  36  and actuation track  37  at a different circumferential position (as compared to  FIG. 13 ) on valve core body  34 , and by forming actuation stop  27  at a corresponding different position (as compared to  FIG. 13 ) on housing portion  14 , as described above with respect to  FIG. 14 , but such that when actuation stop  27  contacts point E of track  37 , handle  36  forms the desired angle with respect to V. In this embodiment, the shape of the container may be modified so that it is easier for the user to grasp the handle when the valve assembly is in the “closed” position. 
     FIGS. 15–18  show a preferred embodiment of valve assembly  10  in the closed position. Preferably, in this closed position, no portion of container-facing opening  42  is aligned with any portion of liquid-out aperture  20 , as shown in  FIG. 16 . Therefore, no liquid flows through liquid-out passageway  38  within core body  34  between liquid-out aperture  20  and spout  24 . Furthermore, no portion of air channel  46  is exposed to any portion of spout  24 , as shown in  FIGS. 16 and 17 , thereby preventing air-back passageway  44  from allowing the movement of air or liquid between spout  24  and air-back aperture  22 . Although one end of each of passageways  38  and  44  as shown is always substantially completely open (i.e., substantially all of exterior-facing opening  40  is aligned with spout  24 , and substantially all of air-back aperture  22  is aligned with channel  46 ), other embodiments are envisioned without departing from the scope of the present invention wherein, for example, both ends of each passageway open gradually as the actuation angle grows with respect to V. 
     FIGS. 19–22  are views similar to  FIGS. 15–18 , respectively, but show valve assembly  10  in the “minimally ON” position that is shown in  FIG. 10 . Preferably, in this minimally ON position, core body  34  has been rotated to align both a minimal portion of container-facing opening  42  with a portion of liquid-out aperture  20  and substantially all of exterior-facing opening  40  with spout  24 , as shown in  FIG. 20 , thereby allowing liquid to flow between liquid-out aperture  20  and spout  24  through liquid-out passageway  38 . Furthermore, in this minimally ON position, core body  34  preferably has been rotated to align air channel  46  with both a relatively minimal portion of spout  24 , as shown in  FIG. 20  by the portion of channel  46  that extends to at least point Z, and substantially all of air-back aperture  22 , as shown in  FIG. 21 , thereby allowing fluid to flow between air-back aperture  22  and spout  24  through air-back passageway  44 . Core body  34  may have additional geometry that further aids the dispensing of liquid from valve assembly  10 . For example, container-facing opening  42  may be formed through the peripheral surface of core body  34  such that “top” edge  39  of opening  42  is not radial, but instead is chamfered relative to the outer periphery of core body  34 , as shown in  FIG. 20 , to guide liquid downwardly from a container through opening  42  to provide more control to the flow of liquid through liquid-out passageway  38 . 
     FIGS. 23–26  are similar to  FIGS. 15–18 , respectively, but show valve assembly  10  in the “halfway ON” position that is shown in  FIG. 11 . Preferably, in this halfway ON position, core body  34  has been rotated to align both substantially half of container-facing opening  42  with liquid-out aperture  20  and substantially all of exterior-facing opening  40  with spout  24 , as shown in  FIG. 24 , thereby allowing liquid to flow between liquid-out aperture  20  and spout  24  through liquid-out passageway  38 . Furthermore, in this halfway ON position, core body  34  preferably has been rotated to align air channel  46  with both a bigger portion of the spout (compared to that in the “minimally ON” position), as shown in  FIG. 24  by the portion of channel  46  that extends to at least point Z, and substantially all of air-back aperture  22 , as shown in  FIG. 25 , thereby allowing fluid to flow between air-back aperture  22  and spout  24  through air-back passageway  44 . 
     FIGS. 27–30  are similar to  FIGS. 15–18 , respectively, but show valve assembly  10  in the “significantly ON” position that is shown in  FIG. 12 . Preferably, in this significantly ON position, core body  34  has been rotated to align both a significant portion of container-facing opening  42  with liquid-out aperture  20  and substantially all of exterior-facing opening  40  with spout  24 , as shown in  FIG. 28 , thereby allowing liquid to flow between liquid-out aperture  20  and spout  24  through liquid-out passageway  38 . Furthermore, in this significantly ON position, core body  34  preferably has been rotated to align air channel  46  with both a bigger portion of the spout (compared to that in the “halfway ON” position), as shown in  FIG. 28  by the portion of channel  46  that extends to at least point Z, and substantially all of air-back aperture  22 , as shown in  FIG. 29 , thereby allowing fluid to flow between air-back aperture  22  and spout  24  through air-back passageway  44 . 
     FIGS. 31–34  are similar to  FIGS. 15–18 , respectively, but, along with  FIGS. 35–37 , show valve assembly  10  in the “completely ON” position that is shown in  FIG. 13 . Preferably, in this completely ON position, the interaction of actuation stop  27  and point E of actuation track  37  prevents handle  36  from rotating any further in direction W (see  FIG. 13 ). Preferably, in this completely ON position, core body  34  has been rotated to align both substantially all of container-facing opening  42  with liquid-out aperture  20  and substantially all of exterior-facing opening  40  with spout  24 , as shown in  FIG. 32 , thereby allowing liquid to flow between liquid-out aperture  20  and spout  24  through liquid-out passageway  38 . Furthermore, in this completely ON position, core body  34  preferably has been rotated to align air channel  46  with both a bigger portion of the spout (compared to that in the “significantly ON” position), as shown in  FIG. 32  by the portion of channel  46  that extends to at least point Z and as shown in  FIG. 33 , and substantially all of air-back aperture  22 , as shown in  FIG. 33 , thereby allowing fluid to flow between air-back aperture  22  and spout  24  through air-back passageway  44 . 
   Although substantially all of air-back aperture  22  is aligned with air channel  46 , and substantially all of exterior-facing opening  40  is aligned with spout  24  throughout the rotation of core body  34  in the preferred embodiment of  FIGS. 15–37 , it is not outside the scope of the invention to provide a valve assembly with geometry such that both ends of passageway  38  and/or  44  align with different portions of the respective apertures and/or spout as the core body is rotated. Moreover, as is seen in  FIGS. 15–37 , it is preferable that the geometry of air channel  46  and apertures  20  and  22  is such that, in any of the positions described above (and any of the infinite positions therebetween), no portion of air channel  46  is aligned with any portion of liquid-out aperture  20 . This ensures that nothing flowing out from liquid-out aperture  20  can flow back into the container through air-back aperture  22  via air-back passageway  44 . Preferably, seals, such as those described above, are also provided to help ensure that liquid-out passageway  38  and air-back passageway  44  are substantially isolated from one another between apertures  20  and  22 , and spout  24 . 
   Valve core body  34 , as shown in  FIGS. 4–37 , provides air-back passageway  44  along air channel  46  formed in its surface and liquid-out passageway  38  between openings  40  and  42  formed through its surface. However, in an alternate embodiment of a valve core body of the present invention, the two passageways may both be provided along channels in the surface of a core rotatable within valve housing  12  for aligning spout  24  with liquid-out aperture  20  and air-back aperture  22 . Such an embodiment is shown in  FIGS. 38–49 . 
   Valve core  132 , shown in  FIGS. 38–41 , preferably includes a substantially cylindrical valve core body  134  attached at one end to a handle  136  that preferably is substantially perpendicular to the longitudinal axis A 2  of core body  134 . Preferably, a liquid-out passageway  138  (see  FIGS. 43 and 47 ) is formed about core body  134 , along a liquid channel  140  that is formed into the peripheral surface of core body  134 . In a preferred embodiment, liquid channel  140  is formed into the surface of core body  134  to a depth b, and is substantially rectangular in shape, having a height H 2  and a length L 2 , as shown, although many other shapes may be used without departing from the scope of the present invention. An air-back passageway  144  (see  FIGS. 44 ,  47 , and  48 ), similar to air-back passageway  44 , is preferably formed about core body  134 , along an air channel  146  that is formed into the peripheral surface of core body  134 . In a preferred embodiment, air channel  146  is formed into the surface of core body  134  to a depth t 1 , and extends circumferentially about core body  134  from a first end j 1  to a second end k 1 . Preferably, air channel  146  is wider at second end k 1  than at first end j 1 . In this preferred embodiment, a portion of air channel  146  extends away from handle  136  to at least a point Z 1  along the length of core  132 . 
   Core body  134  is shown to extend substantially along longitudinal axis A 2 , from end  133 , past liquid channel  140  and air channel  146 , to a closed end  135  shared by handle  136 . In a more particularly preferred embodiment, core  132  includes an actuation track  137 . Track  137  is formed into the periphery of handle  136  closest to end  135 , from a point F 1  to a point E 1 , for limiting the rotation range of core  132  within a valve housing (as described above with reference to actuation track  37 ). Like valve core  32 , valve core  132  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, or linear low-density polyethylene, and preferably is formed of the same material as body portion  14 . 
     FIGS. 42–49  show how valve housing  12  of  FIGS. 1–3C  and valve core  132  of  FIGS. 38–41  may be combined to form valve assembly  110  of the present invention.  FIGS. 42–45  are similar to  FIGS. 15–18 , respectively, and  FIGS. 46–49  are similar to  FIGS. 31–34 , respectively, but represent valve assembly  110  instead of valve assembly  10 . 
   Valve core body  34 , as shown in  FIGS. 4–37 , provides air-back passageway  44  along air channel  46  formed in its surface and liquid-out passageway  38  between openings  40  and  42  formed through its surface. However, in an alternate embodiment of a valve core body of the present invention, the two passageways each may be provided between a respective exterior-facing opening and a respective container-facing opening in a core rotatable within valve housing  12  for aligning spout  24  with liquid-out aperture  20  and air-back aperture  22 . Such an embodiment is shown in  FIGS. 50–61 . 
   Valve core  232 , shown in  FIGS. 50–53 , preferably includes a substantially cylindrical and hollow valve core body  234  attached at one end to a handle  236  that preferably is substantially perpendicular to the longitudinal axis A 3  of core body  234 . Preferably, a liquid-out passageway  238  (see  FIGS. 55 and 59 ) is formed within core body  234 , between an exterior-facing opening  240  and a container-facing opening  242  that are formed through the peripheral surface of core body  234 . Preferably, container-facing opening  242  is substantially rectangular, having a height H 3  and a length L 3 , as shown. A substantially separate air-back passageway  244  (see  FIGS. 56 and 60 ) is preferably formed within core body  234 , between an container-facing opening  246  and an exterior-facing opening  248  that are formed through the peripheral surface of core body  234 . Preferably, container-facing opening  246  is substantially rectangular, having a height G and a length d 1 , as shown, although many other shapes may be used without departing from the scope of the present invention. 
   Core body  234  is shown to extend substantially along longitudinal axis A 3 , from a preferably open end  233 , across openings  240 ,  242 ,  246 , and  248 , to a preferably closed end  235  shared by handle  236 , although end  233  may conceivably be closed in other embodiments. In a more particularly preferred embodiment, core  232  includes an actuation track  237 . Track  237  is formed into the periphery of handle  236  closest to end  235 , from a point F 2  to a point E 2 , for limiting the rotation range of core  232  within a valve housing (as described above with reference to actuation track  37 ). Like valve core  32 , valve core  232  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, or linear low-density polyethylene, and preferably is formed of the same material as body portion  14 . 
     FIGS. 54–61  show how valve housing  12  of  FIGS. 1–3C  and valve core  232  of  FIGS. 50–53  may be combined to form valve assembly  210  of the present invention.  FIGS. 54–57  are similar to  FIGS. 15–18 , respectively, and  FIGS. 58–61  are similar to  FIGS. 31–34 , respectively, but represent valve assembly  210  instead of valve assembly  10 . 
   Each of valve assemblies  10 ,  110 , and  210 , as shown in  FIGS. 9–61 , provides a core body within a housing body portion, preferably such that the core body is rotatable about a longitudinal axis shared by the core body and housing body portion preferably to regulate not only the flow of liquid from a container through a liquid-out passageway but also the flow of fluid between the container and the ambient atmosphere through an air-back passageway. However, in an alternate embodiment of a valve assembly of the present invention, a valve assembly may be provided in which the core body is translatable along a longitudinal axis shared by the core body and housing body portion, preferably to regulate not only the flow of liquid from a container through a liquid-out passageway but also the flow of fluid between the container and the ambient atmosphere through an air-back passageway. Such an embodiment is shown in  FIGS. 62–75 . 
   Valve housing  312 , as shown in  FIGS. 62–65  preferably includes a substantially hollow body portion  314  attached to a container fitment portion  316 , which preferably extends from periphery or surface section  318  of body portion  314  substantially perpendicularly to longitudinal axis A 4  of body portion  314 . Preferably, two apertures—a liquid-out aperture  320  and an air-back aperture  322 —are formed through periphery  318  of body portion  314  to allow liquid and air to move between the hollow of body portion  314  and fitment portion  316 , although any larger number of apertures may be provided. 
   In a preferred embodiment, liquid-out aperture  320  is substantially semi-circular, having a diameter D 2 , and air-back aperture  322  is substantially rectangular, having a height d 2  and a length D 3 , which, for example, may be substantially equal to D 2 . In addition, a distance h 1  substantially separates the top of aperture  320  from the top of aperture  322 , as shown, to provide a pressure difference between the container end of air-back aperture  322  and the container end of liquid-back aperture  320 , for reasons explained above with respect to valve assembly  10 . Extension tube  323  (not shown) preferably is provided to lower the pressure at the container end of air-back aperture  322  even more as compared to that at the container end of liquid-out aperture  320 , for reasons also explained above with respect to valve housing  12  and as shown in  FIG. 3C . Opposite fitment portion  316 , a spout portion  324  preferably extends from body portion  314  for dispensing liquid from body portion  314  to a user and for supplying external air to body portion  314 . Preferably, spout  324  provides a substantially “U-shaped” opening, having a diameter D4 and a side-length h 2 , which, for example, may be substantially equal to h 1 . 
   Body portion  314  is shown extending along longitudinal axis A 4 , from preferably closed end  326 , past spout portion  324  and apertures  320  and  322 , to preferably closed end  328 . In a more particularly preferred embodiment, an actuation track  321  is formed through periphery  318  of body portion  314  from a point F 3  substantially adjacent apertures  320  and  322  to a point E 3  substantially near end  326 , and a pin  319  extends in substantially the same direction as spout  324  from a portion of surface  327  of fitment portion  316  that is separated from periphery  318  as a pivot for an actuator of a valve core (described below). Like valve housing  12 , housing  312  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, linear low-density polyethylene, or other polymer. 
   Fitment portion  316 , similar to fitment portion  16 , preferably includes screw threads  330  to allow attachment of housing  312  to a threaded collar around an orifice in a side-wall of a liquid container (not shown). It will be appreciated that housing  312  may be attached to a container in other ways, such as with a snap-fitted collar, or by gluing or ultrasonic welding, etc. It should be noted that this attachment may be made at any angle relative to the bottom of the container (i.e., relative to the liquid level inside the container), as explained above with respect to valve assembly  10 . 
   As seen in  FIGS. 66–68 , valve core  332  preferably includes a substantially long and substantially solid valve core body  334  having a dispensing side  343  and a source side  345 , that extends along a longitudinal axis A 5  (which when assembled with valve housing  312  preferably is substantially coincident with axis A 4  of  FIG. 62 ) from end  333  to end  335 . In a more particularly preferred embodiment, an extension  347  extends from end  335  along axis A 5  that includes pin  341 . However, in an other embodiment, pin  341  could extend from source side  345  near end  335 , although the core body might have to be made longer. Either way, a handle or actuator  336  preferably rotates at pin  319  of fitment portion  316  about an axis A 6  that is substantially perpendicular to A 5  (see  FIG. 74 ). Slot  339  is preferably formed through handle  336  for converting rotation of handle  336  into translational motion of core body  334  by interaction with pin  341 . In an other embodiment (not shown), pin  319 , and the hole in handle  336 , through which pin  319  extends, could be replaced by a molded living hinge, where handle  336  is attached to valve housing  312 . 
   Preferably, a liquid-out passageway  338  (see  FIGS. 70 ,  71 , and  76 ) is formed by a liquid-out gap  340  through core body  334 , between dispensing side  343  and source side  345 . In a preferred embodiment, liquid-out gap  340  is substantially semi-circular, having a diameter D 5 , which, for example, may be substantially equal to D 2 . Preferably, an air-back passageway  344  (see  FIGS. 70 ,  71 , and  76 ) is formed by an air-back gap  342  through core body  334 , between dispensing side  343  and source side  345 . In a preferred embodiment, air-back gap  342  is substantially rectangular, having a height d 3  and a length D 6 , which, for example may be substantially equal to d 2  and D 3 , respectively. Like valve core  32 , valve core  332  may be formed from any suitable material such as high-density polyethylene, low-density polyethylene, polypropylene, linear low-density polyethylene, or other polymer, and preferably is of the same material as body portion  314 . 
     FIGS. 69–76  show how valve housing  312  of  FIGS. 62–65  and valve core  332  of  FIGS. 66–68  may be combined to form valve assembly  310  of the present invention. Preferably, core body  334  creates a seal within the hollow of body portion  314  and is translatable along longitudinal axis A 4 , which is shared by core body  334  and body portion  314 . Pin  341  preferably extends through track  321  of body portion  314  and through slot  339  of handle  336 . Through rotation of handle  336  about axis A 6 , and the interaction of pin  341  with slot  339  and the ends of track  321 , core body  334  translates within body portion  314  along axis A 4  such that the geometry of housing  312  and core  332  (described above) preferably regulates not only the flow of liquid from a container, through liquid-out aperture  320 , liquid-out passageway  338 , and spout  324  to the user, but also the supply of external air through spout  324 , air-back passageway  344 , and air-back aperture  322  to the interior of the container above the liquid level therein. As in the case of valve assemblies  10 ,  110 , and  210 , once a partial vacuum is created inside the container, valve assembly  310  also preferably provides a seal between the housing and the core that is sufficient to substantially maintain the partial vacuum inside the container after the valve is closed. 
     FIGS. 69–71  are front elevational views of valve assembly  310  having core  332  actuated to two different positions, although there may be an infinite amount of positions therebetween, as indicated by the location of pin  341  between ends E 3  and F 3  of track  321 .  FIG. 69  shows valve assembly  310  in a “closed” position. In this position, pin  341  of core body  334  is located essentially at end F 3 , and handle  336  is rotated as far as possible in direction C 1 . 
   Preferably, in this closed position shown in  FIG. 69  and also in  FIGS. 72 and 73 , no portion of liquid-out gap  340  is aligned with any portion of liquid-out aperture  320  and spout  324 . Therefore, the solid of core body  334  covers substantially all of liquid-out aperture  320  and spout  324 , thereby preventing the flow of liquid through liquid-out passageway  338  within the hollow of body portion  314  between liquid-out aperture  320  and spout  324 . Furthermore, no portion of air-back gap  342  is aligned with any portion of air-back aperture  322  and spout  324 . Therefore, the solid of core body  334  covers substantially all of air-back aperture  322  and spout  324 , thereby preventing the flow of fluid through air-back passageway  344  within the hollow of body portion  314  between air-back aperture  322  and spout  324 . 
     FIG. 70  shows valve assembly  310  in a “halfway ON” position. In this position, pin  341  of core body  334  is essentially halfway between end F 3  and end E 3 . 
   Preferably, in this halfway ON position shown in  FIG. 70  and also in  FIG. 74 , core body  334  has been translated to align substantially half of liquid-out gap  340  with substantially half of liquid-out aperture  320  and spout  324 , thereby allowing liquid to flow between liquid-out aperture  320  and spout  324  through liquid-out passageway  338 . Furthermore, in this halfway ON position, core body  334  preferably has been translated to expose substantially half of air-back gap  342  with substantially half of air-back aperture  322  and spout  324 , thereby allowing fluid to flow between air-back aperture  322  and spout  324  through air-back passageway  344 . 
     FIG. 71  shows valve assembly  310  in a “completely ON” position. In this position, pin  341  of core body  334  is located essentially at end E 3 , and handle  336  is rotated as far as possible in direction W 1 . 
   Preferably, in this completely ON position shown in  FIG. 71  and also in  FIGS. 75 and 76 , core body  334  has been translated to align substantially all of liquid-out gap  340  with substantially all of liquid-out aperture  320  and spout  324 , thereby allowing liquid to flow between liquid-out aperture  320  and spout  324  through liquid-out passageway  338 . Furthermore, in this completely ON position, core body  334  preferably has been translated to expose substantially all of air-back gap  342  with substantially all of air-back aperture  322  and spout  324 , thereby allowing fluid to flow between air-back aperture  322  and spout  324  through air-back passageway  344 . 
   The core body in the embodiment of  FIGS. 69–76  moves translationally by actuation of handle  336 . Other mechanisms for moving the core translationally can be provided. For example, the core body and the housing body portion may be threaded so that rotation of the core body, in a manner similar to the embodiments of  FIGS. 15 ,  42 , and  54 , also causes translation of the core body. 
   A dust cover  400  for shielding the spout of a valve assembly of the present invention when it is not dispensing liquid is shown in  FIGS. 77 and 78 . Cover  400  includes face portion  402 , plug portion  404 , stop portion  406 , and tamper portion  408  with breakaway nub  409 . Preferably, face portion  402  is large enough to cover substantially all of spout  424  of valve assembly  410 , which may be similar to assembly  10  and which is partially shown in  FIG. 78 . Extending away from face  402  is plug portion  404  that is preferably about the same shape as spout  424 , but of a size that can fit within spout  424  when cover  400  is inserted into assembly  410  along direction X. In a preferred embodiment, the relative sizes of the spout and the plug are such that, when inserted into valve assembly  410 , it is difficult for cover  400  to be removed therefrom unintentionally. Stop portion  406  extends from plug  404  to a particular length, such that when cover  400  is inserted into valve assembly  410 , stop  406  contacts a portion of valve core body  434  therein to substantially bar actuation of the core to a position which can permit dispensation of liquid through spout  424 . For example, stop  406  may extend into exterior-facing opening  440 . Finally, nub  409  of tamper portion  408  may be frangibly affixed to a part of valve assembly  410  before valve assembly  410  is initially used. 
   In order to dispense liquid through a valve assembly provided with a dust cover  400  of the present invention, the cover must be removed in a direction substantially opposite to direction X 1  (as explained above). When initially removed, nub  409  preferably breaks away from valve assembly  410 . If a user finds that initial removal is too easy, in that nub  409  need not be broken off its attachment to valve assembly  410 , the user may take that as a sign of tampering. Once initially removed, the user may put dust cover  400  back into its original position in order to keep dirt and debris out of the spout between uses, and preferably also to prevent actuation of the valve to a position which can permit dispensing of liquid through the spout. 
   Thus it is seen that a valve assembly for dispensing and controlling a smooth and continuous outflow of liquid, even from an unvented or rigid container, has been provided. It should be noted that the shapes and sizes of the liquid-out apertures, liquid-out gaps, air-back apertures, air-back gaps, spouts, exterior-facing openings, container-facing openings, and channels described above are only exemplary. One skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow.