Abstract: A spring loaded, tamperproof plug valve such as a pressure gas stop has the rotatable valve plug resiliently retained against removal from the valve body by two stacked, slit, frustoconical, transversely arched spring washers that have teeth which make a one-way tight friction fit on a projecting end portion of the valve plug, and the outer peripheral portion of the forward of the two washers bears on a recessed planar area of the valve body which is surrounded by a continuous boss so a prying tool cannot be inserted beneath either washer. A self-threading sheet metal nut forms a thread in a reduced extremity of the valve plug and has a concentric integral skirt which bears on the teeth and also on the crown of the arched slit washer. The plug can be removed only by destroying the washer or the valve, either of which renders it inoperative. The nut will strip before the spring washers can be compressed enough to "lock" the plug in the valve body.

Abstract: A vapor recovery nozzle for use in filling vessels with a liquid and for recovering liquid vapors generated by the liquid such as the filling of vehicle fuel tanks. The nozzle includes a valve system including a first valve for the liquid and a second valve for the vapor and an interconnection whereby the vapor valve is always open whenever the liquid valve is open. It also includes a common actuator for the two valves and an automatic shutoff system for the liquid valve, which automatic shutoff system includes a connection to the vapor line when the nozzle is being used in vacuum assisted vapor recovery systems and further forms part of a drain system for a vapor collection hood surrounding the spout of the nozzle so as to drain liquid received therein from the vapor flow path to preclude such vapor from contaminating components of a vapor recovery system.