Abstract:
A slit valve ( 10 ) to selectively restrict the passage of a fluent substance between an interior environment ( 17 ) and an exterior environment ( 15 ) and a method for forming the valve ( 10 ), the method including the steps of providing at least one layer of film material and permanently deforming the film material to define a valve ( 10 ) for selectively restricting the passage of a fluent substance between an interior environment ( 17 ) and an exterior environment ( 15 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to valves and systems for selectively controlling the flow of a fluent substance, and more particularly relates to valves for selectively restricting the flow of a fluent substance between an interior environment and an exterior environment, such as, for example, valves for dispensing a product from a container or other source. 
       BACKGROUND OF THE INVENTION 
       [0002]    One type of flexible, resilient valve is a self-closing, slit-type valve mounted by a fitment to a port of a fluent substance container or other source of fluent substance. Such valves have a slit or slits which define a normally closed orifice that opens to permit flow therethrough in response to an increased pressure differential across the valve (e.g., resulting from an increased pressure within the container when the container is squeezed, or from a reduced external ambient pressure compared to the pressure within the container). Such valves are typically designed so that they automatically close to shut off flow therethrough upon a reduction of the pressure differential across the valve. 
         [0003]    Designs of such valves and of fitments using such valves are illustrated in the U.S. Pat. No. 5,271,732, No. 5,927,446, No. 5,942,712 and No. 6,545,901. Often, the fitment is in the form of a closure that includes a body or base mounted on the container neck to define a seat for receiving the valve and includes a retaining ring or other structure for holding the valve on the seat in the base. See, for example, U.S. Pat. No. 6,269,986 and No. 6,566,016. The valve is normally closed and can withstand the weight of the fluid product when the container is completely inverted so that the liquid will not leak out unless the container is squeezed. With such a system, the lid or cap need not be re-closed (although it is typically re-closed if the package is to be transported to another location, packed in a suitcase, etc.). 
         [0004]    While such valves and valve systems have significant advantages and function well, there is always room for improvement. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with one feature of the invention, a slit valve is provided to selectively restrict the passage of a fluent substance between an interior environment and an exterior environment. The valve includes a flexible, resilient head, an annular, peripheral attachment portion, and an annular, flexible, resilient, intermediate portion. The head is centered on a central axis and extends laterally therefrom and has an interior surface to face an interior environment, an exterior surface to face an exterior environment, and confronting, openable portions to define a normally closed orifice in an unconstrained condition wherein the openable portions can move in a first direction to an open orifice configuration and return in an opposite direction to a closed configuration. The interior surface of the head is one of a convex surface or a concave surface, and the exterior surface of the head is one of a convex surface or a concave surface. The attachment portion is centered on the central axis and spaced laterally from the head. The intermediate portion is centered on the central axis and extends laterally from the head to the peripheral attachment portion. The intermediate portion has an interior surface to face the interior environment, and an exterior surface to face the exterior environment. The interior surface of the intermediate portion is one of a concave surface and a convex surface, and the exterior surface of the intermediate portion is one of a concave surface and a convex surface. The head and the intermediate portion are formed from a film of material that has undergone a permanent deformation to define the head and the intermediate portion. 
         [0006]    In accordance with one feature, the interior surface of the head and the exterior surface of the intermediate portion are convex surfaces, and the exterior surface of the head and the interior surface of the intermediate portion are concave surfaces. 
         [0007]    As one feature, the head has at least one self-sealing slit through the head, and the confronting openable portions extend along the at least one self-sealing slit. 
         [0008]    In one feature, the uniform material thickness T is in the range of 0.001 to 0.010 inches. 
         [0009]    According to one feature, the attachment portion has a planar interior surface spaced from a planar exterior surface by the uniform material thickness T. 
         [0010]    In one feature, the attachment portion has an interior surface spaced from an exterior surface by a non-uniform material thickness that varies over the annular extent of the attachment portion. As a further feature, the exterior surface of the attachment portion defines a cylindrical wall that surrounds the head and the intermediate portion. In another further feature, the interior surface and the exterior surface of the attachment portion define a radially outwardly extending annular lip. 
         [0011]    As one feature, the head and the intermediate portion have a uniform material thickness T spacing the exterior surfaces from the interior surfaces, with T being no greater than 0.020 inch. 
         [0012]    According to one feature, the entire valve is defined by a permanently deformed film of material. 
         [0013]    In one feature, the valve is combined with a fluent substance container having an opening through which fluent substance can pass between an interior of the container and the exterior environment, and a fitment sealingly mounted to the container, with the valve sealing mounted in the fitment to extend across the opening to restrict passage of a fluent substance between the interior of the container and the exterior environment at least when the openable portions are in the closed configuration. 
         [0014]    In accordance with one feature of the invention, a method is provided for forming a slit valve to selectively restrict the passage of a fluent substance between an interior environment and an exterior environment. The method includes the steps of providing at least one layer of film material, and permanently deforming the film material to define a valve having a flexible, resilient head, an annular, peripheral attachment portion, and an annular, flexible, resilient, intermediate portion. The head is centered on a central axis and extends laterally therefrom, and has an interior surface to face an interior environment, and an exterior surface to face an exterior environment. The interior surface of the head is one of a convex surface or a concave surface, and the exterior surface of the head is one of a convex surface or a concave surface. The attachment portion is centered on the central axis and spaced laterally from the head. The intermediate portion is centered on the central axis and extends laterally from the head to the peripheral attachment portion, and has an interior surface to face the interior environment and an exterior surface to face the exterior environment. The interior surface of the intermediate portion is one of a concave surface and a convex surface, and the exterior surface of the intermediate portion is one of a concave surface and a convex surface. 
         [0015]    As one feature, the step of permanently deforming provides the head and intermediate portion with a uniform material thickness T spacing the exterior surfaces from the interior surfaces, with T being no greater than 0.020 inch. 
         [0016]    In one feature, the step of permanently deforming further includes defining the annular attachment portion to have the uniform material thickness T. 
         [0017]    According to one feature, the step of permanently deforming further includes defining the annular attachment portion to have a planar exterior surface and a planar interior surface. 
         [0018]    In one feature the uniform material thickness T is in the range of 0.001 to 0.010 inches. 
         [0019]    As one feature, the method further includes the step of forming at least one self-sealing slit in the head and confronting, openable portions along the at least one slit in the head to define a normally closed orifice in an unconstrained condition wherein the openable portions can move in a first direction to an open orifice configuration and return in an opposite direction to a closed configuration. 
         [0020]    According to one feature, the step of providing at least one layer of film material includes providing a plurality of layers of film material and the step of permanently deforming includes permanently deforming the plurality of layers to define the valve. 
         [0021]    As one feature, the step of permanently deforming includes thermoforming the at least one layer of film to define the valve. In a further feature, the step of thermoforming includes matched die forming to define the valve. 
         [0022]    In one feature, the step of providing the at least one layer of film includes injection molding a preformed component having the annular attachment portion and the at least one layer of film extending radially inwardly from the annular attachment portion. 
         [0023]    Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, from the claims, and from the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    In the accompanying drawings forming part of the specification, and in which like numerals are employed to designate like parts throughout the same; 
           [0025]      FIG. 1  is an enlarged isometric view from above of a valve embodying the present invention, with the valve shown in a closed condition; 
           [0026]      FIG. 2  is an enlarged isometric view from below of the valve of  FIG. 1 , again showing the valve in the closed condition; 
           [0027]      FIG. 3  is a top plan view of the valve of  FIGS. 1-2 , again with the valve in the closed condition; 
           [0028]      FIG. 4  is a section view taken from line  4 - 4  in  FIG. 3 ; 
           [0029]      FIG. 5  is a view similar to  FIG. 1 , but showing the valve in the open condition; 
           [0030]      FIG. 6  is a view similar to  FIG. 2 , but showing the valve in the open condition; 
           [0031]      FIG. 7  is a view similar to  FIG. 3 , but showing the valve in the open condition; 
           [0032]      FIG. 8  is a view similar to  FIG. 4 , but showing the valve in the open condition; 
           [0033]      FIG. 9  is an isometric view from above of a fluid dispensing package including a fluent substance container, a fitment in the form of a closure, and the valve of  FIGS. 1-8 ; 
           [0034]      FIG. 10  is an exploded isometric view from above of the package of  FIG. 9 ; 
           [0035]      FIG. 11  is an enlarged, fragmentary sectional view taken from line  11 - 11  in  FIG. 9  and showing the valve in the closed condition; 
           [0036]      FIG. 12  is a view similar to  FIG. 11 , but showing the valve in the open condition; 
           [0037]      FIG. 13  is an isometric view from above of another fluid dispensing package including a fluid substance container, a fitment, and the valve of  FIGS. 1-12 ; 
           [0038]      FIG. 14  is another isometric view of the package of  FIG. 13 , showing the valve in the closed condition; 
           [0039]      FIG. 15  is a view similar to  FIG. 14 , but showing the valve in the open condition; 
           [0040]      FIG. 16  is an exploded isometric view of the package of  FIGS. 13-15 ; 
           [0041]      FIG. 17  is an enlarged sectional view taken from line  17 - 17  in  FIG. 14  and showing the valve in the closed condition; 
           [0042]      FIG. 18  is an isometric view from above of another embodiment of a valve according to the invention, with the valve shown in a closed condition; 
           [0043]      FIG. 19  is an isometric view from below of the valve of  FIG. 18 , again showing the valve in the closed condition; 
           [0044]      FIG. 20  is a top plan view of the valve of  FIG. 18 , again with the valve in the closed condition; 
           [0045]      FIG. 21  is an enlarged section view taken from line  21 - 21  in  FIG. 20 ; 
           [0046]      FIG. 22  is a view similar to  FIG. 18 , but showing the valve in the open condition; 
           [0047]      FIG. 23  is a view similar to  FIG. 19 , but showing the valve in the open condition; 
           [0048]      FIG. 24  is a view similar to  FIG. 20 , but showing the valve in the open condition; 
           [0049]      FIG. 25  is a view similar to  FIG. 21 , but showing the valve in the open condition; 
           [0050]      FIG. 26  is an isometric view of a dispensing package similar to the dispensing package of  FIGS. 9-12 , but showing the valve of  FIGS. 18-25 ; 
           [0051]      FIG. 27  is an exploded isometric view of the dispensing package of  FIG. 26 ; 
           [0052]      FIG. 28  is a fragmentary, section view taken from line  28 - 28  in  FIG. 26 , and showing the valve in a closed condition; 
           [0053]      FIG. 29  is a view similar to  FIG. 28 , but showing the valve in an open condition; 
           [0054]      FIG. 30  is an isometric view of another dispensing package including the valve of  FIGS. 18-29 ; 
           [0055]      FIG. 31  is another isometric view of the package of  FIG. 30  and showing the valve in the closed condition; 
           [0056]      FIG. 32  is a view similar to  FIG. 31 , but showing the valve in the open condition; 
           [0057]      FIG. 33  is an exploded isometric view of the package of  FIGS. 30-32 ; and 
           [0058]      FIG. 34  is an enlarged section view taken from line  34 - 34  in  FIG. 31  and showing the valve in a closed condition. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0059]    While this invention is susceptible of embodiment in many different forms, this specification and the accompanying drawings disclose only one specific form as an example of the invention. The invention is not intended to be limited to the embodiment so described, however. The scope of the invention is pointed out in the appended claims. 
         [0060]    For ease of description, the valve of this invention may be described, along with a fitment, in a typical (upright) position, and terms such as upper, lower, horizontal, etc., are used with reference to this position. It will be understood, however, that the valve embodying this invention may be manufactured, stored, transported, used, and sold in an orientation other than the position described. 
         [0061]    Figures illustrating the valve of this invention and the associated fitments show some conventional mechanical elements that are known and that will be recognized by one skilled in the art. The detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention. 
         [0062]    A presently preferred embodiment of a valve according the invention is illustrated in  FIGS. 1-17  and is designated generally by the number  10 . The valve  10  includes a flexible, resilient central portion or head  12  having a first or exterior surface  14  facing an exterior environment (shown generally at  15  in  FIGS. 4 and 8 ) and a second or interior surface  16  facing an interior environment (shown generally at  17  in  FIGS. 4 and 8 ) in the illustrated and preferred embodiment. The valve  10  further includes a peripheral attachment portion or flange  19 , and a flexible, resilient intermediate portion or sleeve  20  that extends laterally outwardly from the head  12  to the flange  19 . Hereinafter, the term “sleeve”  20  is used in this specification, but in the claims the term “intermediate portion”  20  is used. 
         [0063]    The valve  10  is a self-closing, slit-type valve and is preferably formed as a unitary structure from a film of material that is flexible, pliable, elastic, and resilient. As commonly understood in the art, and as used herein, the term “film” refers to a material that is planar (unconstrained condition) and having a thickness of 0.020 inch or less. For use in the present invention, the preferred materials can include linear low-density polyethylene (LLDPE), low density polyethylene (LDPE), LLDPE/LDPE blends, acetate, acetal, ultra-high-molecular-weight polyethylene (UHMW), polyester, urethane, ethylene-vinyl acetate (EVA), polypropylene, and high density polyethylene. Although less preferred, the material can also include other elastomers, such as a synthetic, thermosetting polymer, including silicone rubber, such as the silicone rubber sold by Dow Corning Corp. in the United States of America under the trade designations DC-99-525 and RBL-9525-54. The valve  10  can also be formed from other thermosetting materials or from other elastomeric materials, or from thermoplastic polymers or thermoplastic elastomers, including those based upon materials such as thermoplastic propylene, ethylene, and styrene, including their halogenated counterparts. 
         [0064]    The valve  10  is preferably formed from a film of material that has undergone a permanent deformation to define at least the head  12  and the intermediate portion  20 . In this regard, the film of material can be permanently deformed utilizing a suitable thermal forming process, which includes matched die forming, vacuum forming, plug assist forming, vacuum snap back forming, billow forming, free forming, pressure forming, drape forming, in-line thermal forming, twin sheet forming, and thin and thick gauge thermal forming, Other suitable processes include cast film extrusion, cold forming, in-mold labeling technology, in-mold assembling technologies, blow molding in a die set against a preform, roto forming, rotary “chip shot” molding, radio frequency (RF) forming, localized laser heating, etching processes to warp the film into a valve shape, and UV (ultraviolet) curing of a formed valve. In one highly preferred process for the valve  10  shown in  FIGS. 1-17 , the entire valve  10  is formed from a film of LLDPE/LDPE blend material that has been permanently deformed in a matched die forming process wherein the illustrated shapes of the head  12 , the sleeve  20 , and the radially inner portion of the peripheral attachment portion  19  are formed by permanently deforming the film of material, with the radially outer portion of the peripheral attachment portion  19  having the same planar configuration as the film material. 
         [0065]    The sleeve  20  has an exterior surface  24  and an interior surface  26 . In the illustrated and preferred embodiment, the exterior surfaces  14  and  24  of the head  12  and sleeve  20  are separated from the interior surfaces  16  and  26  by a uniform material thickness T ( FIG. 4 ). Preferably the thickness T is less than or equal to 0.020 inches, and in more highly preferred embodiments the thickness T is in the range of 0.001 inch to 0.010 inch, and in even more highly preferred embodiments, the thickness T is in the range of 0.003 to 0.007 inches. In the illustrated embodiment, the thickness T is equal to 0.005 inch. 
         [0066]    As best seen in  FIGS. 3 and 8 , the head  12  has planar, intersecting, self-sealing slits  28  which together define a closed orifice when the valve  10  is in the closed condition. It will be understood that in the as-formed, closed condition of the valve  10  shown in  FIGS. 1-4 , each slit  28  is closed and does not define an open slot. Preferably, the slits  28  are equally spaced from each other and equal in length. In the illustrated form of the valve  10 , the slits  28  define six, generally sector-shaped, equally sized flaps or petals  30  in the head  12 . The flaps or petals  30  may also be characterized as “openable regions” or “openable portions” of the valve head  12 . Each flap or petal  30  has a pair of diverging transverse faces  32  ( FIG. 8 ) defined by the slits  28 , and each transverse face  32  seals against a confronting transverse face  32  of an adjacent petal  30  when the valve  16  is closed. While the valve  10  can be formed with the slits  28 , it is preferred that the slits  28  be subsequently cut into the head  12  of the valve  10  by suitable conventional techniques. As another alternative, at least one slit  28  could be partially formed into the head  12 , with the remainder of the at least one partially formed slit  28  being cut, severed, punctured, torn, broken or otherwise separated after molding. In this regard, it should be understood that as used herein, the term “slit valve” is intended to refer to any valve that has one or more slits, such as slits  28 , in its final functioning form, including such a valve wherein one or more of the slits, such as a partially formed slit  28 , is/are only fully completed after the valve has been formed and/or installed in its operational environment, such as, for example, a valve  10  having at least one partially formed slit  28  with a frangible portion installed in a fitment of a dispensing package or machine, with the frangible portion of the at least one partially formed slit  28  being intact during installation and then cut, severed, punctured, torn, broken or otherwise separated after installation to complete the at least one slit  28  and place the valve  10  in its final functioning form. 
         [0067]    It is to be understood that the orifice of the valve  10  may be defined by structures other than the illustrated straight slits  28 . Further, the slits  28  may have various different shapes, sizes and/or configurations in accordance with the requirements and parameters of each particular application. For example, the orifice may also include only one slit  28  or two or more intersecting slits  28 . 
         [0068]    The valve  10  has a normally closed position or condition shown in  FIGS. 1-4 . The valve  10  is typically designed to remain closed when the pressure differential across the valve head  12  is below a predetermined amount, with the petals  30  defining a normally closed orifice configuration. The valve  10  can be forced to one or more open positions or configurations, as shown in  FIGS. 5-8 , when a sufficiently high pressure differential is applied across the valve  12  thereby moving the petals  30  in a first or opening direction toward the exterior environment to an open orifice configuration. When the pressure differential across the valve  10  is decreased sufficiently, the inherent resiliency of the valve  10  allows the valve  10  to return to the normally closed condition (by action of the force generated from the resilient valve&#39;s deformational stresses). 
         [0069]    The head  12 , peripheral attachment portion  19 , and sleeve  20  are preferably all symmetrical bodies of revolution centered on a central axis  27 . Preferably and as illustrated in  FIGS. 1-4 , in the as-formed, unconstrained, closed condition, the exterior surface  14  of the head  12  is concave, the interior surface  16  of the head  12  is convex, the exterior surface  24  of the sleeve  20  is convex, and the interior surface  26  of the sleeve  20  is concave. Furthermore, as best seen in  FIG. 4 , the exterior surface  14  and the interior surface  16  of the head  12  include planar portions  14 A and  16 A, respectively, extending transversely from the central axis  27  over a limited area adjacent the axis  27 . Additionally, the exterior surface  14  and the interior surface  16  of the head  12  include arcuate portions  14 B and  16 B, respectively, extending laterally from the planar portions  14 A and  16 A to connect with the sleeve  20 . Furthermore, the exterior surface  24  and the interior surface  26  of the sleeve  20  includes arcuate portions  24 A and  26 A, respectively, extending radially outwardly from the head  12  to respective frustoconical portions  24 B and  26 B of the exterior surface  24  and interior surface  26 , which in turn extend laterally outwardly to respective arcuate surfaces  24 C and  26 C of the exterior surface  24  and interior surface  26 . Additionally, the arcuate surfaces  24 C and  26 C extend laterally outwardly to connect the peripheral attachment portion  19 . It should be appreciated that the head  12  and sleeve  20  are the functional features of the valve  10  that impact the performance of the valve  10 , with the attachment portion  19  serving merely as a structure to mount the valve  10  in a fluent substance handling or dispensing system. 
         [0070]    In the illustrated embodiment and as best seen in  FIG. 4 , the peripheral attachment portion  19  has an exterior surface  34  and an interior surface  36 , with radially extending, planar portions  34 A and  36 B extending from the sleeve  20  to cylindrical portions  34 B and  36 B which extend axially to radially extending, planar portions  34 C and  36 C. Preferably, blend radiuses connect the arcuate portions  24 C and  26 C to the planar portions  34 A and  36 A, respectively, connect the planar portions  34 A and  36 A to the cylindrical portions  34 B and  36 B, respectively, and connect the cylindrical portions  34 B and  36 B to the planar portions  34 C and  36 C. 
         [0071]    The exterior surfaces  14  and  24 , respectively, of the head  12  and sleeve  20  intersect at a first circular line of intersection, shown diagrammatically at  40  in  FIGS. 1 ,  3 ,  4 ,  5  and  7 , which is defined at an inflection point between the convex exterior surface  24  and the concave exterior surface  14  in the illustrated and preferred embodiment. The exterior surface  24  of the sleeve  20  intersects the peripheral attachment portion  19  at a second circular line of intersection, shown diagrammatically at  42  in  FIGS. 1 ,  3 ,  5  and  7 . The interior surface  16  of the head  12  and the interior surface  26  of the sleeve  20  intersect at a third circular line of intersection, shown diagrammatically at  44  in  FIGS. 2 and 6 , which is defined at an inflection point between the convex interior surface  14  and the concave interior surface  26 . The interior surface  26  of the sleeve  20  intersects the peripheral attachment portion  19  at a fourth circular line of intersection, shown diagrammatically at  46  in  FIGS. 2 and 6 . 
         [0072]    In the as-formed, unconstrained, closed condition shown in  FIGS. 1-4 , the second circular line of intersection  42  is spaced axially in the second direction (toward the interior environment  17 ) from the first circular line of intersection  40 . Furthermore, the fourth circular line  46  of intersection is also spaced axially in the second direction from the third circular line of intersection  44 . Additionally, the first, second, third, and fourth circular lines of intersection  40 ,  42 ,  44 , and  46  lie in parallel planes extending transverse to the central axis  27 . 
         [0073]    The valve  10  is typically employed in applications wherein the valve  10  is mounted in or to a fluent substance dispensing system, such as a bottle or container, for dispensing or discharging a fluent substance through the valve  10  when a sufficient pressure differential is applied across the valve head  12  to open the valve. Typically, the valve  10  is oriented at the opening of a container holding a fluent substance such that the valve head exterior surface  14  faces outwardly toward the exterior ambient environment and such that the valve head interior surface  16  faces inwardly toward the container interior and interfaces with the fluent substance within the container. The typical operation of such a valve  10  involves the user first tipping the container to point the valve  10  in a downward direction and then applying a pressure differential to the valve head  12  (as by sucking on the exterior side of the valve and/or by squeezing a flexible wall or walls of the container). This causes the valve  10  to open as shown in  FIGS. 5-8 . 
         [0074]    It should be understood the valve  10  may find use with many different types and constructions of closures, containers, and other sources and conduits of fluent substances, that a fluid dispensing package  50  including a fluent substance container  52  and a fitment in the form of a closure  54  is shown in  FIGS. 9-12  for purposes of illustration, and that the particular forms or constructions of the fluid dispensing package  50 , container  52 , and closure  54  form no part of the invention unless expressly recited in an appended claim. For purposes of illustration, the closure  54  comprises a base  56  and a closure lid  58 . The base  56  includes a deck  60  having a dispensing port  62  defined therein, and a skirt  64  extending downwardly from the deck  60  and having retention and sealing features, shown generally at  66  in  FIG. 11 , for engagement with a neck  68  of the container  52  that surrounds a dispensing port  69  of the container  52 . The lid  58  is connected to the base  56  by a snap hinge  70  of any suitable construction and includes a rim  72  having a snap fit connection with the base  56  when the lid  58  is placed in a closed condition. The container  52  and the closure  54  are molded from a suitable plastic material, many of which are known. The planar portion  34 C of the peripheral attachment portion  19  is joined to an interior, planar surface  74  of the deck  60  by any suitable means to form a sealed structural connection that maintains the head  12  of the valve extending across the ports  62  and  69  of the container  52 , including, for example, by heat bonding, adhesive bonding, and material bonding such as could be achieved by injection molding. In operation, the valve  10  can be moved from the closed condition shown in  FIGS. 9-11  to the open condition shown in  FIG. 12  by a user applying pressure to the exterior side walls of the container  52  to increase the pressure differential across the head  12  of the valve  10  to dispense fluid substance from the container  50  via the port  69  and valve  10 . 
         [0075]    By way of further example,  FIGS. 13-17  show another dispensing package  80  in which the valve  10  can be employed, with the package  80  including a fluid substance container in the form of a pouch  82  and a fitment  84 . The pouch  82  includes side walls in the form of two flexible web portions  86  and  88  that are joined and sealed to together such as by heat welding to each other at their peripheral edges and to a wedge shaped tailpiece  90  of the fitment  84 . The web portions  86  and  88  are typically made from a flexible, heat-sealable, polymeric sheet or from a flexible, paperboard or metal foil sheet having a heat-sealable, polymeric lining. The fitment  84  is typically molded from a suitable plastic, many of which are known. The fitment  84  includes a dispensing spout  92  with a dispensing port  94  extending through the tailpiece  90  and the spout  92  for dispensing fluid substance from the pouch  82 . As best seen in  FIG. 17 , the planar portion  34 C of the peripheral attachment portion  19  is joined to an interior, planar surface  96  of the fitment  94  by any suitable means to form a sealed structural connection that maintains the head  12  of the valve extending across the port  94 , including, for example, by heat bonding, adhesive bonding, and material bonding such as could be achieved by injection molding. In operation, the valve  10  can be moved from the closed condition shown in  FIGS. 14 ,  16 , and  17  to the open condition shown in  FIG. 15  by a user applying pressure to the exterior of the web portions  86  and  88  of the pouch  82  to increase the pressure differential across the head  12  of the valve  10  to dispense fluid substance from the pouch  82  via the port  94  and valve  10 . 
         [0076]    While the dispensing packages  50  and  80  show the valve  10  being mounted to the respective closures via the planar portion  34 C of the attachment portion  19 , it should be understood that any portion  34 A,  36 A,  34 B,  36 B,  34 C, and  36 C of the attachment portion  19  can be joined to a corresponding surface of a fitment or other fluid system component to provide a suitable mounting for the valve  10 . In this regard, if the portions  34 B and/or  36 B are so joined, the portions  34 C and  36 C can be eliminated if desired. Similarly, if the portions  34 A and/or  36 A are so joined, the portions  34 B,  36 B,  34 C and  36 C can be eliminated if desired. 
         [0077]      FIGS. 18-25  show another embodiment of the valve  10  that is identical to the valve  10  of  FIGS. 1-17  except for the number of slits  28  (two rather than three) and the peripheral attachment portion  19 , which is provided in the form of a more ridged, cylindrical mount ring/seal than the relatively thin, planar shape used in the attachment portion  19  of the embodiment of  FIGS. 1-17 . In this regard, the peripheral attachment portion  19  of the embodiment of  FIGS. 18-34  includes cylindrical portions  34 B and  36 B of exterior surface  34  and interior surface  36 , respectively, which are spaced by a material thickness that is several times thicker than the material thickness T of the head  12  and sleeve  20 . The portions  34 B and  36 B define a cylindrical wall  100  that surrounds the head  12  and the sleeve  20 . Furthermore, the exterior and interior surfaces  34  and  36  of the attachment portion  19  define a radially outwardly extending seal/mount lip  102 . In the regard, the exterior and interior surfaces  34  and  36  further include arcuate portions  34 D and  36 D, respectively, that extend laterally outwardly from the portions  34 B and  36 B, respectively, with the portion  34 D extending to a frustoconical portion  34 E, and the portion  36 D extending to a planar portion  36 E. The portions  34 E and  36 E extend to a cylindrical portion  104  that defines the radial outermost extent of the lip  102 . 
         [0078]    As seen in  FIGS. 26-29 , the embodiment of  FIGS. 18-25  is assembled in the dispensing package  50 , but the attachment portion  19  provides a different mount configuration than the attachment portion  19  of the embodiment of  FIGS. 1-17 . Specifically, the lip  102  provides a snap-fit engagement past radially inwardly extending, annular ribs  106  provided in a cylindrical spout  108  in the deck  60  of the closure  84 , with the cylindrical portion  104  being in frictional, sealed engagement with an interior, cylindrical surface  110  of the spout  108 . 
         [0079]    As seen in  FIGS. 30-34 , the embodiment of  FIGS. 18-25  is assembled in the dispensing package  80 , but with the attachment portion  19  again providing a different mount configuration than the attachment portion  19  of the embodiment of  FIGS. 1-17 . Specifically, the lip  102  provides a snap-fit engagement past a radially inwardly extending, annular rib  112  provided in a cylindrical wall  113  of the fitment  92 , with the cylindrical portion  104  being in frictional, sealed engagement with an interior, cylindrical surface  114  of the wall  113 . 
         [0080]    The head  12  and the sleeve  20  of the valve  10  of  FIGS. 18-34  are preferably formed from a film of material that has undergone a permanent deformation to define at least the head  12  and the intermediate portion  20 . In this regard, the film of material can be permanently deformed utilizing a suitable thermal forming technique, which includes matched die forming, vacuum forming, plug assist forming, vacuum snap back forming, billow forming, free forming, pressure forming, drape forming, in-line thermal forming, twin sheet forming, and thin and thick gauge thermal forming. Other suitable processes include cast film extrusion, cold forming, in-mold labeling technology, in-mold assembling technologies, blow molding in a die set against a preform, roto forming, rotary “chip shot” molding, radio frequency (RF) forming, localized laser heating, etching processes to warp the film into a valve shape, and UV (ultraviolet) curing of a formed valve. In a preferred process for the valve  10  of  FIGS. 18-34 , a preformed component is first made via injection molding of EVA or LDPE so that a film layer is surrounded by the cylindrical portions  34 B, and then the shape of the valve head  12 , sleeve  20 , and portions  34 A and  36 A of the attachment portion  19  are formed using a suitable thermal forming process. In another preferred process, the entire valve  10  of  FIGS. 18-34  is formed in its final shape by an injection molding of EVA or LDPE. 
         [0081]    While the valves  10  have been shown herein in connection with specific embodiments of fluid dispensing systems for purposes of illustration, the valves  10  of the present invention may be used with a variety of conventional or special fluent substance handling and/or holding systems, including glass or plastic bottles, flexible tubular containment structures, containers, tanks, vessels, tubing, medical devices and other equipment or apparatus, the details of which, although not fully illustrated or described, would be apparent to those having skill in the art and an understanding of such systems. The particular fluent substance handling or holding system, per se, forms no part of, and therefore is not intended to limit, the broad aspects of the present invention. It will also be understood by those of ordinary skill that novel and non-obvious inventive aspects are embodied in the described exemplary valves  10  alone. 
         [0082]    As previously discussed, the valves  10  are typically designed to close when the pressure differential across the valve head  12  drops below a predetermined amount. The inherent resiliency of the valve  10  allows the valve  10  to return to the unactuated, closed condition (by action of the force generated from the resilient valve&#39;s deformational stresses). Preferably, the valve  10  is sufficiently stiff so that it remains closed under the weight or static head of the substance in the container bearing against the interior surfaces  10  and  26 , but the valve  10  is flexible enough to open when the valve head  12  is subjected to an increased pressure differential greater than a predetermined magnitude. 
         [0083]    The valves  10  are also typically designed to be flexible enough for use in various applications where it is necessary or desirable to accommodate in-venting of ambient atmosphere. To this end, as the valve  10  closes, the closing petals or openable portions  30  can continue moving inwardly past the closed position to allow the valve petals  30  to open inwardly when the pressure on the valve head exterior surface  14  exceeds the pressure on the valve head interior surface  16  by a predetermined magnitude. Such in-venting of the ambient atmosphere helps equalize the interior pressure in the container with the pressure of the exterior ambient atmosphere. Such an in-venting capability can be provided by selecting an appropriate material for the valve construction, and by selecting appropriate thicknesses, shapes, and dimensions for various portions of the valve head  12  for the particular valve material and overall valve size. The shape, flexibility, and resilience of the valve head, and in particular, of the petals  30 , can be designed or established so that the petals  30  will deflect inwardly when subjected to a sufficient pressure differential that acts across the head  12  in a gradient direction toward the valve interior side (second side  40 ). Such a pressure differential might occur after a quantity of a substance is discharged through the valve  10 , and a partial vacuum is created on the inside of the valve  10 . When the valve  10  closes, if there is a partial vacuum in the container, and if the pressure differential across the valve  10  is large enough, the valve petals  30  will deflect inwardly beyond the initial closed position/condition to an open configuration so as to permit in-venting of the ambient atmosphere into the container to assist in equalizing the internal pressure with the external pressure. As the external and internal pressures equalize, the inwardly displaced petals  30  will move back out to the initial, closed position/condition. 
         [0084]    If it is desired to provide particular dispensing characteristics, then the dispensing valve  10  is preferably configured for use in conjunction with (1) the characteristics or shape of the particular supply reservoir (not shown—but which may establish the maximum height (i.e., static head) of the substance or product in the reservoir), (2) the characteristics of the particular substance or product, and (3) any relevant characteristics of the other dispensing system components. For example, the viscosity and density of the fluent substance product can be relevant factors in designing the specific configuration of the valve  10 . The rigidity and durometer of the valve material, and size and shape of the valve head  12 , can also be relevant to achieving some desired dispensing characteristics, and can be selected for accommodating the normal range of pressure differential that is expected to be typically applied across the valve head, and for accommodating the characteristics of the substance to be dispensed therefrom. 
         [0085]    It should be understood that while specific embodiments of the valve  10  have been shown and described herein, there are many variations that may be desirable for the valve depending upon the particular requirements. For example, while the head  12  and the sleeve  20  have been shown as having the uniform material thickness T, in some applications it may be desirable for the material thickness to vary from the head  12  to the sleeve  20 , or to vary within the head  12  and/or the sleeve  20 . By way of further example, while a number of surfaces have been described herein as having a specific shape (concave, convex, frustoconical, planar, etc) other specific shapes may be desirable for those surfaces depending upon the particular application. 
         [0086]    It will be readily observed from the foregoing detailed description of the invention and from the illustrations thereof that numerous other variations and modifications may be effected without departing from the true spirit and scope of the novel concepts or principles of this invention. 
         [0087]    It should be appreciated that by forming all or part of the valves  10  by permanently deforming a film of material, the valves  10  can be produced at a reduced cost and/or weight in comparison to conventional slit valves that are molded and require a greater material thickness in at least the head of the valve, such as the valve described in the Background Of The Invention section of this disclosure.