Self-closing valve-and-lid assembly

Self-closing two-piece valve-and-lid assembly adapted for closing the open top end of a container fillable with pressurized product, and having a central assembly axis, comprising

• (I) a lid the periphery of which is adapted for being sealingly connected with a top rim of a container sidewall surrounding the said container top opening, and extending generally transverse to said central assembly axis,
• (i) said lid having a central dome and a central opening in the middle of said lid dome, and being rigid under conditions of filling product into, and discharging product from said container,
• (ii) said lid extending generally in a main lid plane transverse to said central assembly axis,
• (iii) said lid dome having a top wall having an outer face and an opposite inner surface facing inward toward the interior of said dome, and a circumferential sidewall which latter extends generally at an angle out of said main lid plane,
• (iv) said lid dome comprising a collar portion extending axially relative to said central assembly axis and ending in an annular shoulder means about said central dome opening;
• (II) a valve body of elasticaly resilient material, comprising
• (a) a valve disc part having an outer face adapted for facing away from a container and an opposite underside face resting, in a peripheral disc zone, on an annular zone of said inner surface of said dome top wall,
• (b) a reduced radial diameter valve stem depending from said underside face of said valve disc part and extending axially relative to said central assembly axis, said valve stem having an outer surface;
• (c) a valve head at the lower end of, and being of larger radial diameter than, said valve stem, and having an annular face extending in a plane transverse to said central assembly axis, said annular valve head face facing toward said annular shoulder of said collar portion and bearing a first contact zone on said valve head,
• (d) a cavity being open in said outer face of said disc part forming a rim therein, and extending from said opening axially downward at least into said valve stem and having a bottom end located near the radial plane in which said first contact zone of said valve head extends,
• (e) additional annular sealing means about said valve stem spaced from said valve head and adapted for making sealing contact at all times with said lid dome collar portion in a second contact zone axially spaced from said first contact zone,
• (f) duct means in said valve stem, having at least one exit opening for product flow in said cavity and at least one entry opening in a region of the outer surface of said valve stem and head extending from said first to short of said second contact zone thereon,
• (g) said valve body having a deformable portion thereof located in a region comprising a part of said valve stem above said duct therein and an annular part of said valve disc vicinal to said valve stem,
• which deformable portion is stretched in axial downward direction toward the interior of a container when said valve-and-lid assembly is opened, `(h) the distance of said annular upward face of said valve head from the underside face of said valve disc part, prior to said valve body being mounted in said lid dome, being shorter than the distance between these same two valve body elements when said valve body is mounted in said lid dome, thereby imparting a bias to said annular upward face of said valve head against said annular shoulder means of said collar portion, thereby biassing said first contact zone of said valve head, when in closed state, into sealing contact with said annular shoulder of said collar portion.