Safety valve for vehicle fuel tank - has float which seals against vent port and is held in place by spring and weight if vehicle turns over

摘要

The safety valve for an automobile fuel tank has a cylindrical housing (1) connected to the tank by the pipe (12) and to the vent pipe (19) by the outlet (9). A float (2) with a hemispherical head slides in guides (13) and is supported by a flange (15) on an annular weight (16). When the tank is being filled, any air in the pipe (12) flows out through the hole (6) and into the vent pipes. As the level of the fuel rises, the float rises and seals the hole (6) to prevent escape of fuel through the vent pipe (10). If the vehicle turns upside down in an accident, the weight (16) and spring (17) overcome the buoyancy of the flat (2) and keep it pressed over the hole (6).