Abstract:
A pressure relief valve that is mountable to protect packaging so as to vent pressurized gases contained within the packaging. The present invention also pertains to a pressure relief valve which includes at least one passageway defined by at least one inner rail and which is in communication with an aperture.

Description:
[0001]    This application is a continuation-in-part of Ser. No. 09/705524. The present invention relates to a pressure relief valve that is mountable to product packaging so as to vent pressurized gasses contained within the packaging. More specifically, the present invention is a pressure relief valve which includes at least one passageway defined by at least one inner rail and which is in communication with an aperture. 
     
    
     
       BACKGROUND OF THE INVENTION  
       SUMMARY OF THE INVENTION  
         [0002]    Pressure relief valves are often used to vent product packaging which contains materials which may produce gasses. In flexible wall packaging or containers, a build-up of gasses within the container often distorts the appearance of the product or damages the packaging, among other things. To prevent excessive pressure from building within the container, a pressure relief valve is used to vent the gasses while also sealing the contents from the environment through the use of a flexible film or membrane.  
           [0003]    However, in use, and especially when numerous cartons are packaged together in bulk, the operation of the film is often obstructed or impeded by an adjoining carton which is placed in contact with the membrane or film. To solve this problem, outer rails are often used which prevent an object from physically contacting the flexible film. This, of course, leads to use of additional materials, manufacturing steps, and ultimately, increased costs.  
           [0004]    The present invention eliminates the use of outer rails through the use of at least one inner rail that defines a passageway which is recessed from an aperture located on the valve. In a closed position, the film covers the aperture, and in an open position, the film is raised above the aperture to permit the aperture to be in communication with the passageway in order to vent the container. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0005]    These and other features, objects and advantages of the present invention will become apparent from the following description and drawings wherein like reference numerals represent like elements in several views, and in which:  
         [0006]    [0006]FIG. 1 is a perspective view of a first exemplary embodiment of the invention.  
         [0007]    [0007]FIG. 2 shows how pressure relief valves may be formed on rolls.  
         [0008]    [0008]FIG. 3 is a cross sectional view taken along line  3 - 3 .  
         [0009]    [0009]FIG. 4 is a cross sectional view taken along line  4 - 4 .  
         [0010]    [0010]FIG. 5 is another cross sectional view taken along line  4 - 4 .  
         [0011]    [0011]FIG. 6 is a perspective view of an alternative embodiment of the present invention.  
         [0012]    [0012]FIG. 7 illustrates an alternate embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    Set forth below is a description of what are currently believed to be the preferred embodiments or best examples of the invention claimed. Future and present alternatives and modifications to the preferred embodiments are contemplated. Any alternates or modifications having insubstantial changes in function, in purpose, in structure or in result are intended to be covered by the claims of this patent.  
         [0014]    As shown in FIG. 1, one embodiment of the present invention includes a pressure relief valve  10  having a base  11  which may include an adhesive layer  12  and a release liner  14 . The adhesive layer  12  allows the base to be mounted to a package or support surface  16 .  
         [0015]    An aperture  20  is included on base  11  which is often located over an opening on package  16 . Base  11  may be made of a number of materials known to those of skill in the art including Polyethylene Terephthalate by DuPont Teijin Films.  
         [0016]    As is also shown in FIGS.  1 - 5 , inner rails  22  and  24  are provided on base  11 . Inner rails  22  and  24  may be an adhesive layer that has been applied to the base or of some other suitable material known to those of skill in the art. The thickness of the inner rails should be about 1 to 10 millimeters, with a thickness of 4-6 millimeters being preferred.  
         [0017]    The inner rails are located a spaced distance from aperture  20  to form a passageway  30  which is recessed from aperture  20 . As show in FIG. 6, in another embodiment of the present invention, a single inner rail  135  may also be provided which forms a passageway  130  that is recessed from aperture  20 . Of course, the shape of base  111  may be generally circular or oval as shown in FIG. 6 or 4-sided as shown in FIG. 1. In addition, other shapes would work as well.  
         [0018]    A film or membrane  50  or  150  is also provided which is supported by inner rail  135  or inner rails  22  and  24 . The film may be made of Polyethylene Terephthalate by DuPont. In addition, a plurality of pressure relief valves  10  may be formed on a roll  60  as shown in FIG. 2 in a manner known to those of ordinary skill in the art.  
         [0019]    In operation, as shown in FIG. 3, film  50  is in a closed position and extends inwardly to cover aperture  20 . In this position, film  50  acts as a seal which prevents exposure to the outside environment.  
         [0020]    To vent the contents, film  50  moves into an open position through the force created by the pressurized gas located in container  16 . The pressure moves film  50  up off of aperture  20 . This, in turn, permits aperture  20  to be in communication with the passageway so as to allow venting to occur. Once the pressure in the package equalizes, film  50 , again, moves inwardly to cover and seal off the aperture.  
         [0021]    As is also shown in FIG. 3, in an open position, the passageway and aperture form an opening that is stepped in configuration which permits venting to occur. By permitting film  50  to move downwardly and upwardly within space defined by the passageway, contact by extraneous surfaces or objects with film  50  will not interfere with the operation of valve  50 . This, in turn, eliminates the need to use outer rails with the device.  
         [0022]    As shown in FIG. 7, an alternate embodiment of the present invention concerns a valve  399  which includes a release liner  400 , adhesive  402 , base  404 , and an elastomeric film  408  which is attached to base  404  by adhesive  406 . As described above, this embodiment forms a channel or passageway  412  as well. However, by using an elastomeric film  408 , the size of channel  412  may be increased by the ability of the film to balloon outwardly  410  past base  404  when subject to pressure created by outflowing gas. In other words, when in an open position, said film is arcuate or curved in shape. This ability to create a larger than normal passageway  412  allows the valve to handle sudden high flow volumes of air or other gasses that may be encountered. This prevents the container from rupturing when subjected to this condition. A suitable elastomeric film  408  is Exxon 318.92 EVA LD. Of course, other expandable films known to those of ordinary skill in the art maybe used as well. The operation of this embodiment is otherwise as was described above.  
         [0023]    While the invention has been described with reference to the preferred embodiments thereof, it will be appreciated that numerous variations, modifications, and alternate embodiments are possible, and accordingly, all such variations, modifications, and alternate embodiments are to be regarded as being within the spirit and scope of the invention.  
         [0024]    It should be understood that various changes and modifications to the preferred embodiments described would be apparent to those skilled in the art. Changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is, therefore, intended that such changes and modifications be covered by the following claims.