Fast fuel system

A Fast fuel system allows speedy refuelling of vehicles. Most large earthmoving and mining vehicles with diesel fuel tanks over 150 U.S. gallons (568 liters) are equipped with fast refueling systems. Fast refueling systems utilize an automatic shut off fuel nozzle, receiver and level control device. Fast refuel systems operate by connection of a fill nozzle to the vehicle's fuel tank and a source mounted pump delivers fuel into the tank at rates up to 150 U.S. gallons (568 liters) per minute.

Fast fill systems in general allow for ground level refueling and automatic shut-off upon a full tank. Ground level refueling increases operator safety as climbing onto vehicles during refueling is not necessary as the fill point receiver may be located in a location on the vehicle which is easily accessed.

Pressurized refuel system

Pressurized refuel systems were developed in the 1950’s and installed on almost all large vehicles. Caterpillar introduced a non-pressurized refueling system in 1998 on the Caterpillar D11 track type tractor replacing the original pressurized system.

Pressurized refuel systems operate via sealing the fuel tank at the appropriate fill point thus creating internal pressure. The automatic shut off nozzle shuts off when pressure in the fuel system reaches 9 psi (62 kPa) or greater. Due to the pressure introduced into the fuel tank, most tanks require additional structure to prevent bursting or damaged weld joints.

Non-pressurized refuel system

Non-pressure refuel systems operate via a closed loop system where all pressure is contained interior to signal lines, level control, and a shut-off valve. When the fuel tank fill point is reached, a bleed line signal is closed and back pressure is applied to a diaphragm valve at the fuel entry point. Due to differential pressure and an internal spring, the diaphragm is forced closed and cannot be overfilled. Non-pressurized refueling systems do not require tank pressurization for automatic nozzle shut-off, thus allowing their use on thin-walled metallic and composite material fuel tanks.

Caterpillar found that the non-pressurized refuel system reduced fuel spills and provided more accurate filling when used with worn automatic refuel nozzles. David Juleff of Shaw Development, LLC [ [http://shawdev.com/fastfill.html Shaw Development - Fluid Products - Fast Fill Refueling Systems ] ] was the design engineer that tailored an aerospace non-pressurized refuel system to be first introduced on the Caterpillar D11 track type tractor in 1998.

Non-pressurized refueling systems meet European directive 97/23/EC [http://www.lne.fr/publications_en/directives/97-23e.pdf] which permits their use in the European Union as any tank pressurization during refuel is less than 7.3 psi (0.5 bar).

Installation procedures for non-pressurized fast fill systems are documented in "Fast Fill Fueling Installation for Off-Road Self-Propelled Work Machines SAE J176" [ [http://www.sae.org/technical/standards/J176_200608 Fast Fill Fueling Installation for Off-Road Self-Propelled Work Machines ] ] . Proper installation is important to maintain operator safety and proper functionality of the system.

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Non-pressurized Shaw Development fast fill system installed on a composite fuel tank.

References