Patent ID: 7240796

Claim:
A valve assembly for venting a pressure generated by a gas within an enclosed package containing a food product during a heating of the package, said valve assembly comprising: a tubular body having an open end and a closed end, said tubular body defining a recess between said open and closed ends, said closed end having an aperture for venting the pressure therethrough, and said open end having a flanged portion extending radially outwardly, and that is sealed to an inner edge of an aperture in the package; a retaining member operative for snap-fit engagement with said tubular body, wherein a side of said retaining member adjacent said closed end of said tubular body includes an outwardly protruding rib, and said retaining member is spaced apart from said closed end of said tubular body; and a generally planar membrane element positioned between said closed end of said tubular body and said retaining member and held in place by the rib on said retaining member, to maintain a substantially sealed environment within the package when the pressure in the package is less than a predetermined threshold pressure range of 4–7.5 mbar, and a portion of said membrane element not held by the rib on said retaining member is deformable from an initial position adjacent said closed end while venting the gas through the aperture in said closed end when the pressure in the package exceeds the predetermined threshold pressure range during heating of the package and the deformed portion of the membrane element returns to the initial position adjacent the closed end to seal the apertures when the pressure in the package has equalized with ambient air pressure, and said membrane element is formed from cast polypropylene so as to not permanently deform from heating of the package.