One way valve

摘要: A one way valve for flexibly walled packages is disclosed. The comprises a unitary body (20) having an outer face (22) with raised anvil (24) first valve seat (26) surrounding central depression (28). generally planar surface provided adjacent the (24) forming second (30). The seat (30) terminates in outer wall (32) which includes a marginal portion (34) extending towards and (36) away from (24). An elastic diaphragm (38) also provided seats on at least part of being below marginal wall. At least aperture (44) through from to inner (46). aperture opens at end onto other indented (46). filter (58) housed across other opening. body securable web (8) packaging around (36). web (8), when so secured, stretched has hole (6) punched therein. Pressure, apertures, can raise the subsequently portion (26).