Tank-to-tank transfer of diesel fuel is a potentially dangerous process; every safety precaution need be taken. Static electricity can ignite vapors. Ultimately, the safest method of fuel transfer is to avoid electrical connections entirely. Pumps powered with compressed air are well suited for diesel fuel transfer. Air powered double diaphragm pumps (APDD, aka AODD) utilize a 100 psi air connection to actuate movement of two diaphragms within the pump, thereby creating flow.
Although AODD pumps are made by several manufacturers, there are specific pump features to look for when selecting a diesel transfer fuel pump:
Ease of serviceability – all mechanical equipment requires maintenance. Field applications require on-site service and maintenance. The air valves in double diaphragm pumps do wear out over time and will require service or parts replacement. Outside accessibility of the air valve permits servicing the air valve while maintaining the fluid connections; pumps remain in-service.
Pump construction – diaphragms require replacement regularly, depending on the viscosity and aggressiveness of the fluids. Pump reassembly can be challenging: misalignment of the pump housing can cause leaks, creating vaporous pools of fuel. Pumps equipped with bolted housings, as opposed to a clamp type band, are near fool-proof for precision reassembly.
Portability – the ability to build a transportable diesel transfer fuel rig is determined by the pump that drives the operation. Air powered double diaphragm pumps can be mounted to vehicles or even carried by hand into the field.
Safe to operate – vehicles accumulate static electricity which can discharge near vapors. Air powered double diaphragm pumps can operate remotely within reach of the air supply line. AODD diesel transfer fuel pumps are non-electric, therefore intrinsically safe.
Tank level control – large diesel fuel transfer requires monitoring, best accomplished by a liquid level controller. Liquid level controllers provide user-designated levels to cutoff pump operation. They work with one or two pumps, accessing tank full condition, tank empty, or both.