Pressure relief one-way valve, hermetic container and method to manufacture a pressure relief one-way valve

Abstract

The present invention relates to pressure relief one-way valves for hermetic packaging, A pressure relief one-way valve for hermetic packaging is provided, comprising a valve body (A), a valve cap (B) and a valve membrane (C), wherein the valve body (A) comprises a base ( 13 ) comprising a sealing seat ( 11 ) for the valve membrane (C) and one or more holes ( 6 ) adapted to let the gas flow through the valve ( 1 ), wherein the valve cap (B) is housed in the valve body (A) and comprises a pressure relief one-way opening ( 4 ) wherein the valve membrane (C) is flexible and is placed between the valve body (A) and the valve cap (B) in the sealing seat ( 11 ). The pressure relief one-way valve is such that the valve cap (B) comprises a first rib ( 2 ) placed laterally with respect to the pressure relief opening ( 4 ) in order to keep the valve membrane (C) in the sealing seat ( 11 ) so that the valve membrane can lift, during the pressure relief operation, only on one side and so that the portion of the valve membrane (C) free to lift has a length (L, L′) equal to or less than the distance between the first rib ( 2 ) and the non-fixed end ( 12 ) of the valve membrane (C). A hermetic container and a method for manufacturing a pressure relief one-way valve ( 1 ) are also shown.

1 . Pressure-relief one-way valve for hermetic packaging, comprising a valve body, a valve cap and a valve membrane, wherein said valve body comprises a base comprising a sealing seat for said valve membrane and one or more holes adapted to let the gas flow through the valve, wherein said valve cap is housed in said valve body and comprises a pressure-relief opening and wherein said valve membrane is flexible and is placed between said valve body and said valve cap in said sealing seat, wherein said valve cap comprises a first rib placed laterally with respect to said pressure-relief opening so as to keep said valve membrane in said sealing seat so that said valve membrane can lift, during the pressure-relieve operation, only on one side and so that the portion of said valve membrane free to lift has a length equal to or less than the distance between said first rib and the non-fixed end of said valve membrane, and in that said valve cap comprises a second rib, placed on the same side of the valve cap with respect to said pressure-relief opening on which said first rib is placed, so that the portion of said valve membrane free to lift, during the pressure-relief operation has a fixed length smaller than the distance between said first rib and said non-fixed end of said valve membrane. 
     
     
         2 . Pressure-relief one-way valve according to  claim 1 , wherein said fixed length, is equal to at least half of the maximum width of said valve membrane, preferably at least two thirds or four fifths of the maximum width of the valve membrane. 
     
     
         3 . Pressure-relief one-way valve according to  claim 1 , wherein said pressure relief opening is in the center of said valve cap. 
     
     
         4 . Pressure-relief one-way valve according to  claim 1 , wherein said valve membrane has a thickness comprised between 10 micron and 100 micron. 
     
     
         5 . Pressure-relief one-way valve, according to  claim 1 , wherein said valve cap further comprises a projecting element adapted to limit the bend of said valve membrane during the pressure-relief operation. 
     
     
         6 . Pressure-relief one-way valve, according to  claim 1 , wherein the upper surface of said valve cap is coplanar with the upper surface of said valve body. 
     
     
         7 . Pressure-relief one-way valve according to  claim 1 , wherein the upper surface of said valve cap is on a lower level with respect to the upper surface of said valve body. 
     
     
         8 . Pressure-relief one-way valve according to  claim 1 , wherein said valve cap is symmetric with respect to a plane parallel to said base of said valve body and going through a center of said valve cap so that said valve cap has not to be pre-oriented according to a preferential orientation to be placed into the valve body. 
     
     
         9 . Pressure-relief one-way valve according to  claim 1 , wherein said sealing seat is covered by a viscous layer so as to improve the sealing of said valve membrane. 
     
     
         10 . Pressure-relief one-way valve according to  claim 1 , further comprising a filtering element adapted to filter the gas that flows through said one or more holes of said valve body. 
     
     
         11 . Pressure-relief one-way valve according to  claim 10 , wherein said filtering element comprises a non woven polyester. 
     
     
         12 . Pressure-relief one-way valve according to  claim 10 , wherein said filtering element is impermeable to liquids. 
     
     
         13 . Pressure-relief one-way valve according to  claim 1 , wherein said valve body and/or said valve cap are made of biodegradable material. 
     
     
         14 . Pressure-relief one-way valve according to  claim 1 , wherein said valve membrane comprises a non-biodegradable material. 
     
     
         15 . Pressure-relief one-way valve according to  claim 1 , wherein the weight of said valve membrane is equal to 0.1% or less of the total weight of said valve. 
     
     
         16 . Hermetic container, preferably for food products, characterized in that it comprises a comprising the valve according  claim 1 . 
     
     
         17 . Method for manufacturing a pressure relief one way valve for hermetic packaging, comprising a valve body, a valve cap and a valve membrane, wherein said valve body comprises a base comprising a sealing seat for said valve membrane and one or more holes adapted to let the gas flow through the valve, wherein said valve cap is housed in said valve body and comprises a pressure-relief opening and wherein said valve membrane is flexible and it is placed between said valve body and said valve cap in said sealing seat, wherein said method comprises the following steps: formation in said valve cap of a first rib placed laterally with respect to said pressure-relief opening so as to keep said valve membrane in said sealing seat so that said valve membrane can lift, during the pressure-relieve operation, only on one side and so that the portion of said valve membrane free to lift has a length equal to or less than the distance between said first rib and the non-fixed end of said valve membrane and formation in said valve cap of a second rib placed on the same side of the valve cap with respect to said pressure relief opening on which said first rib is placed, so that the portion of said valve membrane free to lift, during the pressure relief operation has a fixed length less than the distance between said first rib and said non-fixed end of said valve membrane. 
     
     
         18 . Method for the production of a pressure-relief one-way valve according to  claim 17 , wherein said valve membrane is cut from tape and placed in said sealing seat of said valve body in a single method step. 
     
     
         19 . A pressure-relief one-way valve for hermetic packaging comprising:
 a valve body having a base with through holes and a sealing seat circumscribing the through holes;   a valve membrane placed on the sealing seat covering the through holes; and   a valve cap placed within said valve body and held therein, said valve cap having a first rib on one end and a protruding element on another end, the first rib holding a first portion of said valve membrane securely fixed against a first portion of the sealing seat, wherein a second portion of said valve membrane is not fixed against a second portion of the sealing seat and is free to move so as be capable of separating from the second portion of the sealing seat and positioned to contact the protruding element limiting a distance of separation of said valve membrane from the second portion of the sealing seat,   whereby when a pressure is communicated through the through holes the distance of separation of said valve membrane from the second portion of the sealing seat is limited.   
     
     
         20 . The pressure-relief one-way valve of  claim 19  further comprising:
 a second rib formed on said valve cap and positioned between the first rib and the protruding element and having a distal end extending adjacent said valve membrane, 
 whereby said second rib is capable of being positioned so as to contact said valve membrane at a predetermined location away from the first portion of said valve membrane securely fixed against the first portion of the sealing seat and closer to the second portion of said valve membrane not fixed against the second portion of the sealing seat so that opening pressure is capable of being controlled.