Abstract: A pressure sensing piston connected to a valve of a leak detector senses leakage of gasoline from underground piping and restricts the flow of gasoline through the piping whenever any leakage exceeds a certain, predetermined rate of flow. The piston is shiftably received in a piston chamber and carries an inner cylindrical wall that is sealingly engageable with a mating cylindrical seal of structure connected to the piston chamber whenever the valve of the detector is in a leak sensing position to enhance movement of the valve in accordance with relatively small changes in the volume of fluid within the region.

Abstract: A system for recovering and condensing vapors from a liquid process or storage tank in which a shell is connected to the tank for receiving the vapors from the tank, and a vortex tube is adapted to supply a stream of cold air into said shell. The cold air is passed in a heat exchange relation to the vapors in said shell to condense the vapors, and the condensed vapors are passed back to the tank.

Abstract: A liquid dispensing and vapor recovery system and a vapor control unit used therein in which the control unit has a pair of inlets for receiving liquid, such as gasoline, from an underground storage tank and for receiving gasoline vapors from a vehicle tank during dispensing of the gasoline into the latter tank. A first passage is provided in the control unit for passing the gasoline from the storage tank to a hose connected to the vehicle tank, and an additional passage is provided in the control unit for diverting a portion of the gasoline. A valve is provided which controls the flow of gasoline through the additional passage in response to the flow of gasoline through the first passage and an injector nozzle is provided in the additional passage for drawing vapors from the vehicle tank and into the second passage for mixing with the gasoline before being discharged back to the storage tank.

Abstract: A liquid dispensing and vapor recovery system in which an underground storage tank is connected to a first conduit for delivering a liquid, such as gasoline, to a vehicle gasoline tank or the like under the force of a pump located in the storage tank. A second conduit is connected to the first conduit and to the storage tank for diverting a portion of the gasoline in the first conduit back to the storage tank and an injector is located in the second conduit for forming a reduced pressure zone. A third conduit is connected to the vehicle tank and to the second conduit at the reduced pressure zone for drawing the vapors from the vehicle tank into the second conduit for passage into the storage tank. Valve means are provided which are responsive to the rate of flow of the liquid through the first conduit for regulating the flow of vapor through the third conduit.