Fuel saving device

A valve device for restricting the flow of gaseous material into and out of a container for volatile material owing to relative pressure differentials between the interior and exterior of said container, comprising in combination a housing consisting of an upper part and a lower part, a ferrule connecting said two parts with oneanother, a tank conduit in said lower part opening at its lower end toward the interior of said container, a vent conduit in said upper part opening at its upper end toward the exterior of said container and having a threaded outer surface, an enlarged cavity within said lower and upper parts communicating with said vent conduit and said tank conduit, an annular pressure valve gate arranged on the bottom of said cavity, a shaft inserted into a central bore of said annular gate and extending upwardly in the center of said cavity and downwardly toward the upper end of said tank conduit, an annular groove provided at the lower end of said shaft within said annular gate, a first O-ring seal arranged in said annular groove to contact a beveled annular inner surface of said gate, a second O-ring seal placed in an outer annular groove of said gate to contact a beveled annular lower wall surface of said cavity, a pressure relief spring arranged around said shaft within said cavity and abutting at its lower end on the upper surface of said annular gate and at its upper end on the upper surface of said cavity, a stop washer fastened to the upper end of said shaft by means of a groove-clip connection, a vacuum relief spring abutting at its lower end on the upper surface of said annular gate and at its upper end on said stop washer.