Abstract: A dual layer fabric insert fuel strainer is positioned at the inlet of a fuel tank filler tube. It has an inner fabric that coalesces water and passes fuel. It has an outer fabric which is sized to pass fuel but not the water coalesced on the inner fabric. The insert therefore traps water between the fabric layers, preventing its introduction into the fuel tank with fuel.

Abstract: A diesel fuel pick-up tube has two branches in the fuel tank. One is connected to a fuel strainer having openings of approximately 130 microns and the other is connected to a strainer having openings of about 400 to 500 microns. A vacuum relief valve is in the pick-up branch connected to the coarser strainer and is set to open at a predetermined amount of vacuum on the order of five inches of Mercury. The strainer with the finer mesh would therefore normally pass fuel but not wax crystals when the diesel fuel has reached the cloud point. Only if the finer mesh strainer is sufficiently clogged with wax crystals to cause the vacuum in the pick-up tube to open the relief valve would fuel be taken in through the coarser of the two strainers. Both strainers will prevent water from entering the pick-up tube.