The invention is for a safety valve for a piping system. The safety valve has a cylindrical housing, a piston assembly with two disc-shaped pistons, each piston having at least one orifice defined therein, a shaft connecting the pistons, a valve stem, and a stop attached to one end of the valve stem. The safety valve has a valve seat with an opening shaped and sized to receive the stop. The safety valve has a spring positioned in the housing against the piston assembly so that the spring exerts a spring force on the second piston in a direction opposite the direction of fluid flow. When fluid forces acting on the piston assembly exceed a spring force acting on the piston assembly, the piston assembly moves in the direction of flow until the stop engages the valve seat and shuts off flow through the safety valve.
The present invention is for a spill prevention system to prevent fuel spills from a connecting line connecting duel fuel tanks on a truck when the connecting line is severed or detached from one of the reducer fittings to which it is attached. The connecting line provides pressure communication between the fuel tanks so that fuel flows from one tank to the other whenever there is an unequal pressure acting on the fuel, which occurs whenever one tank has more fuel in it than the other. The connecting line connects to the reducer fitting located on each fuel tank. A safety valve is immersed in the fuel in each tank and connected to the reducer fittings. Each safety valve is configured to shut off flow to the connecting line when the connecting line is severed or detached from the one of the reducer fittings.
