Ignition-source free fuel pump

摘要

Apparatus and method for making an immersed fuel transfer pump free of possible sources of ignition for fuel-vapor mixtures when the pump is run dry. The bearings and face seals are cooled by hydraulic oil used to power the pump, preferably through connecting the case leakage port on a conventional multiple piston type hydraulic motor to the pump as a supply and ducting the leakage through the bearings and near the seals on its way to the reservoir. An auxiliary pump built into the centrifugal pump shaft increases flow over these critical parts via a closed loop. Leakage past the dynamic face seals is led overboard through a flame-quenching passage.