Closure with pressure release system

摘要

There is described a neck structure (10) in combination with a closure (40). The neck structure defines a neck opening (14) with a cylindrical sealing surface (18) surrounding the neck opening and an external neck surface (10). The closure comprises a cap formed of resilient material having a top (42) and a downwardly extending skirt portion (48) depending from the top. An annular plug (68) depends from an underside of the top and one or more ribs (80) are formed on an internal surface of the downwardly extending skirt portion. The annular plug and the one or more ribs are arranged concentrically and are dimensioned such that, upon application of the cap to the neck structure, the annular plug projects into the neck opening and engages the cylindrical sealing surface. At the same time the one or more ribs engage the external neck surface. The annular plug is adapted to flex away from the cylindrical sealing surface upon the build up of excess pressure within the closure whereupon circumferentially spaced ends of the or each rib define therebetween a path for the venting of fluid to release the excess pressure. <IMAGE>