Abstract: The anti-siphon device prevents a hose or siphon tube from being inserted into the fuel inlet line for a fuel tank of a vehicle, such as a tractor-trailer. The anti-siphon device includes a tube with cams which are moveable from a retracted position to an extended position via a camming sleeve inserted into the tube. The cams are extended into contact with the inside surface of the fuel tank inlet line and preclude removal of the anti-siphon device from the inlet line. The device further includes flighting which prevents a siphon hose from being inserted through the tube into the fuel tank of the vehicle. Holes are provided in the tube of the device to allow fuel to flow freely into the tank during filling. The fuel also passes through the central opening of the camming sleeve, and through a central opening in the flighting for passage out of the bottom of the tube.

Abstract: The anti-siphon device prevents a hose or siphon tube from being inserted into the fuel inlet line for a fuel tank of a vehicle, such as a tractor-trailer. The anti-siphon device includes a tube with cams which are moveable from a retracted position to an extended position via a camming sleeve inserted into the tube. The cams are extended into contact with the inside surface of the fuel tank inlet line and preclude removal of the anti-siphon device from the inlet line. The device further includes flighting which prevents a siphon hose from being inserted through the tube into the fuel tank of the vehicle. Holes are provided in the tube of the device to allow fuel to flow freely into the tank during filling. The fuel also passes through the central opening of the camming sleeve, and through a central opening in the flighting for passage out of the bottom of the tube.