Abstract: An automatic pump-out for an underground vapor line drop-out tank used at gasoline service stations and related locations. Condensed gasoline vapors and gasoline (liquid) which collect in gasoline service station vapor recovery systems flow by gravity through a vapor line to an underground drop-out tank. An underground storage is located adjacent the drop-out tank. A fill pipe extends from the surface into the storage tank and a discharge pipe connects the storage tank to the surface gasoline pumps. The drop-out tank and storage tank are provided with vent lines. The storage tank contains a vertically positioned pipe, having an open lower end and a closed upper end, extending from the top to adjacent the bottom thereof. A tube connects the bottom of the drop-out tank to the top of the vertically positioned pipe.

Abstract: In the delivery of bulk gasoline to an underground storage tank assurance that the vapor recovery hose is properly connected is provided by sensing of an excess vacuum in the delivery truck tank. Such vacuum occurs when air and/or gasoline vapor is not permitted to replace the gasoline drained from the truck tank. To prevent air from entering the truck tank when the vapor hose is not properly connected to both the truck tank and the storage tank (1) a complete dry break coupling is employed at the vapor hose connection to the underground tank so that vapor cannot be displaced from the storage tank nor can air enter the vapor hose if that connection is not made and (2) a dry break coupling is used only on the truck side of the vapor hose connection to the truck so that air cannot enter the truck tank unless that connection is made.