Abstract:
A unidirectional relief valve of flat kind to be applied inside hermetic containers, characterized by the fact that the cap ( 2 ), which is of circular shape and has a central hole ( 3 ), has a symmetric structure, and on both faces are present identical ribs  ( 5 ), allowing such identity and symmetry to insert the cap ( 2 ) inside the valve body ( 13 ) without the need to pre-orient it.

Description:
FIELD OF THE ART 
       [0001]    The present invention refers to the technological filed of the construction of gas relief valves for sealed hermetic containers. The international classification of reference is B  65   d.    
       STATE OF THE ART 
       [0002]    Some kinds of relief valves have been known on the market for several years. Recently, the market for such valves has seen a rapid growth, that has called for an annual production of billions of units. The high market demand, currently still rising, requires the employment of very fast production plants. 
         [0003]    The problem to be solved is the specific one to realize a kind of valve whose components can be assembled with automatic plants operating with full reliability and efficiency even at high production speed. 
         [0004]    One of the most significant limitations pertains to the delicate assembling operation of the small cap, which needs to be inserted in the matching valve body. Iri the handling and in the proper insertion of said component some operational uncertainties are still present, which are however intolerable at the high production rhythms currently required to satisfy the increased needs of an expanding market. 
         [0005]    It should be highlighted that the valve body present a morphology that is visibly asymmetric for the functional characteristics. 
         [0006]    The main parameter to set the production rhythm of the devices that supervise the robotized assemblage of the relief valves is the operation of cap insertion. 
         [0007]    Each single cap, having preferably a circular shape and a hole in the center, needs to be preliminary oriented, and that requires the use of optical control devices that allow the correct orientation and the positioning of the currently known caps. 
         [0008]    The problem to be solved is to optimize the handling and assemblage of the relief valves, making efficient and infallible their operations, even at very high production speeds, with a considerable economy in the realization of the automatic plant, and in its management without optical control mechanisms. 
         [0009]    Said optimization allows to double the productivity and to make the assemblage more efficient and affordable, allowing to overcome all the operational uncertainties that cause the low reliability and limited productive efficiency. 
         [0010]    Said operational uncertainties slow down the production in a way that can not be accepted anymore in light of the exponential growth of market demand. 
         [0011]    The solution proposed by the present invention solves entirely the problems still present, so that a considerable increase in the production rhythms can be achieved. 
     
    
     
       DESCRIPTION 
         [0012]    The solution consists primarily in the realization of a circular and symmetric cap that can be attached indifferently as a coin with identical faces, presenting no alternatives but only and always the security of a favorable event of correct orientation during the assemblage of the matching valve body. 
           [0013]    The invention, in its surprising but not obvious conceptual simplicity, is now disclosed in details with reference to the figures of drawings attached as an unbinding example. 
           [0014]      FIG. 1  shows in section a valve applied to the inside wall of a container packaged under vacuum and in controlled atmosphere, lower than the outside atmospheric pressure. 
           [0015]    It can be noticed that the valve is represented in a position of hermetic sealing to avoid that the external atmosphere enters inside the container, thus safeguarding the organoleptic features of the content under vacuum or under controlled atmosphere. 
           [0016]    Still in  FIG. 1 , it should be noticed the detail marked with the number ( 7 ) that represents a viscous layer, such as silicon oil, spread between the elastic membrane ( 6 ) and its matching flat seat of hermetic sealing ( 9 ). 
           [0017]      FIG. 2  shows emblematically the beginning of the phase of gas giving off by the packaged product, such as coffee beans freshly roasted. It should be noticed that inside the sealed container ( 1 ) start to develop gases that are emblematically represented by black asterisks given off by the freshly roasted coffee beans. 
           [0018]    It should be pointed out the fact that the external pressure is still above the inner pressure of package that has been sealed under vacuum. 
           [0019]    It should be still noticed the presence of atmospheric pressure outside the package, whose body ( 1 ) has an outlook that is still flat and coplanar adhering to the valve body ( 13 ) and to the relative lock-in closing cap ( 2 ). 
           [0020]    Furthermore, it should be noticed the flexing of the elastic membrane ( 6 ) and its hold on the layer of the silicone oil ( 7 ) pressed against the underneath sealing seat ( 9 ). 
           [0021]      FIG. 3  highlights the balance of the valve with the elastic membrane ( 6 ) that is exactly flat. In such a position the internal pressure Pi balances the external pressure Pe, but the membrane ( 6 ) maintains the hermetic conditions through the viscous layer ( 7 ). 
           [0022]      FIG. 4  highlights the unfolding of the relief action and it can be noticed the oriented lifting up of the elastic membrane ( 6 ) from the relative sealing ( 9 ) seat caused by the internal overpresurre Pi that is higher than the external one Pe. 
           [0023]      FIG. 5  shows the new balance situation at the end of the relief action. 
           [0024]      FIG. 7  shows a diametric section of the circular cap ( 2 ). 
           [0025]      FIG. 6  and  FIG. 8  are external views of the two identical faces of said circular symmetric disk with a central hole ( 3 ). 
           [0026]      FIG. 9  represents in plant the lower external wall of the valve body. 
           [0027]      FIG. 10  shows a median diametric section of the valve body. 
           [0028]      FIG. 11  shows in plant the internal surface of the valve body. 
           [0029]      FIG. 12  is an axonometric representation that highlights the configuration o the three components of the valve:
       valve body ( 13 );   elastic membrane ( 6 );   circular symmetric cap ( 2 );         
       
    
    
       [0033]    In all the figures each single detail is marked as follows:
     1  is the package body that, in the shown example, could be a flexible film of thermo sealable material;     2  is the symmetric circular cap with two identical faces;     3  is a hole that goes through the symmetric cap;     4  is a relief hole on the body ( 1 )     5  are ribs that are identical on both faces of the symmetric cap.     6  is the circular elastic membrane inserted inside the valve body ( 13 ).     7  indicates a layer of silicone oil spread onto the relative seat ( 9 ).     8  indicates the sealing zone of the valve body ( 13 ) inside the sealed package.     9  is the eccentric seat to hold the silicone oil.     10  are relief holes places onto the bottom wall of the valve body ( 13 ).     11  is the bottom wall of the valve body.     12  is a paper-filter diaphragm applied externally of the bottom wall of the valve body ( 13 ).     13  is the valve body that is attached inside the body of the package.   Pe indicates the external atmospheric pressure.   Pi indicates the internal pressure inside the sealed container.   
 
         [0049]    The clearness of the figures highlights all the functional features of the valve of each component. In particular  FIG. 6 ,  FIG. 7  and  FIG. 8  show with extreme clarity the identity of the two faces of the symmetric cap ( 2 ) that can thus be inserted inside the valve body ( 12 ) indifferently with absolute certainty and. 
         [0050]    The inventive core of the present invention rests exactly in the realization of a symmetric cap ( 2 ) that can be inserted indifferently inside the valve body ( 13 ) without any uncertainty even at very high production rhythms without failing to orient it properly. 
         [0051]    It should be highlighted the circumstance that the heuristic gradient of the present invention rests in the simplicity of realization and in the surprising efficiency and reliability even at very high production rhythms. 
         [0052]    The invention of course will be realizable with different structural proportioning and with material and processes of fabrication that are technologically equivalent, given the very own inventive features of the present invention as basically disclosed in the description, drawings and claims. 
         [0053]    Any average technician expert in this technological field will thus be able, now that the inventive combination of the present finding have been disclosed, to realize, with simple logical deductions and without any inventive effort, relief valves, equipped with a symmetric cap, that will be included in the protection sphere of the present invention and reproducing the features as basically described, shown and hereinafter claimed.