Self-closing dispenser

Claim 1

A dispenser comprising a dispenser body defining a generally elongated passage having exit and entrance end portions, said body being molded from synthetic polymeric material and including two diametrically opposite relatively rigid immovable upstanding posts each having first and second end portions adjacent said respective exit and entrance end portions thereby imparting rigidity to said body at diametrically opposite sides thereof, a pair of resilient walls defining said passage, said pair of walls extending laterally between said posts and axially between said exit and entrance end portions, said pair of walls at said entrance end portion each being of an outwardly opening concave configuration, said pair of walls at said exit end portion having inner planar surfaces in total contacting relationship in a common plane whereby upon the flow of a pressurized product from said entrance end portion to said exit end portion said inner planar surfaces progressively open as said resilient walls expand while upon the termination of pressurized product flow said inner plane surfaces progressively close to produce a planar seal therebetween and said pair of resilient walls are of an appreciably thinner cross-sectional thickness than said posts whereby upon cooling of said body after the molding thereof tensile forces are set up in said pair of walls which, due to the rigidity of said pair of posts, maintain said inner planar surfaces in intimate planar contacting relationship prior to and after pressurized product flow.