Automatic fuel dispenser

Abstract

An automatic fuel dispensing system including an automatic dispensing nozzle similar to dispensing nozzles which open manually to dispense liquids and shut-off automatically when tanks such as locomotive fuel tanks near the point of being filled, or for closing an automatic shut-off valve when the dispensing valve is a substantial distance from the tank being filled. The automatic dispensing system is provided with an atmospheric pressure balanced diaphragm and an internal vacuum conduit where the diaphragm operates the shut-off valve when reduced air pressure from the vacuum conduit interrupts the pressure balance of the diaphragm. The tank to be filled is provided with an air conduit connected to the internal vacuum conduit of the automatic dispensing nozzle to operate the cut-off of the nozzle to a point adjacent the outer opening of the tank fill pipe when fuel enters the air conduit. Mounted in the fill pipe of the tank is a fill pipe adapter which cooperates with the nozzle spout of the automatic dispensing nozzle to create a vacuum chamber between the inserted nozzle spout and the adapter wall. To satisfy the vacuum demand of the automatic shut-off valve, the nozzle spout extends into the fill pipe adapter a sufficient distance to provide a narrow opening between the end of the spout and the adapter wall such that when liquid is dispensed from the nozzle spout, air is removed from the vacuum chamber creating a partial vacuum for operating the shut-off valve.