Diesel fuel shut-off device

Fuel shut-off device for use in a fuel tank to discontinue fuel flow to a fuel pump, comprising a valve seat forming a fuel flow opening for fuel to flow from said fuel tank to said fuel pump, a fuel control valve cooperably disposed relative to said valve seat to control fuel flow from said fuel tank to said fuel pump, a spring biasing said fuel control valve in a direction to a closed position against said valve seat, a diaphragm movable in an opposite direction toward said closed position of said fuel control valve to open said fuel control valve against bias of said spring and away from said closed position to allow said spring to close said fuel control valve, said diaphragm having a first valve-actuating side communicated to a fuel chamber for moving said fuel control valve relative to said valve seat against bias of said spring and a second side, said second side being communicated to a control chamber having an inlet orifice that is communicated to said fuel tank and an outlet orifice that is communicated to said fuel pump to provide a relatively higher pressure in said control chamber than in said fuel chamber to move said diaphragm toward said closed position to open said fuel control valve when said inlet orifice is open to said fuel tank and to provide a relatively lower pressure in said control chamber to move said diaphragm away from said closed position to allow said spring to close said fuel control valve when said inlet orifice is closed to said fuel tank, and an inlet orifice valve disposed in said fuel tank 1) to open said inlet orifice to said fuel tank when the fuel level is above a predetermined low level and 2) to close said inlet orifice to said fuel tank when the fuel level is at said predetermined low level.