One way valve

Abstract

A one way valve for flexibly walled packages is disclosed. The valve comprises a unitary valve body having an outer face with a raised anvil having a first valve seat surrounding a central depression. A generally planar surface is provided adjacent the anvil forming a second valve seat. The second valve seat terminates in an outer wall which includes a first marginal portion extending towards the anvil and a second marginal portion extending away from the anvil. An elastic diaphragm is also provided which seats on the second valve seat with at least a part of the diaphragm being below the first marginal portion of the outer wall. At least one aperture is provided through the valve body from the outer face to an inner face. The aperture opens at one end onto the second valve seat and at the other end onto an indented portion of the inner face. A filter is housed in the indented portion across the other end of the aperture opening. The valve body is securable to a web of the flexibly walled packaging around the second marginal portion. The web, when the valve body is so secured, is stretched across the first valve seat and has a hole punched therein. Pressure, in at least one of the apertures, can raise a portion of the diaphragm away from the second valve seat and subsequently raise a portion of the web away from the first valve seat.

Dependencies are inferred from the claim text.