| 1 | Match the Required Flow Rate | 20–150 m³/h Common for truck, tank, and terminal offloading applications | A pump that is too small increases unloading time, while an oversized pump may consume unnecessary energy and create excessive shear or turbulence. | Calculate the required transfer volume divided by the target unloading time. Confirm that the pump can maintain the required flow at the actual system pressure. | Use a variable-speed drive or a flow-control valve when demand changes during loading and unloading. |
| 2 | Check Differential Pressure | 2–8 bar Typical transfer-system differential pressure | Pressure must overcome hose friction, pipe losses, filters, valves, elevation, and any back pressure in the receiving tank. | Estimate total dynamic head from the complete piping route. Select a pump that provides the required flow without operating continuously at its maximum pressure. | A pressure-relief device and a properly sized bypass or recirculation line help protect the pump during a blocked discharge condition. |
| 3 | Consider Oil Viscosity and Temperature | 2–1,000 cSt Depending on product type and operating temperature | Viscosity strongly affects pump efficiency, starting torque, flow stability, and pressure loss through hoses and filters. | Use the highest expected operating viscosity for sizing. For heavy oils, verify cold-start performance and suction capability. | Heating the oil or the suction line can reduce viscosity, but temperature limits must protect the product and seals. |
| 4 | Compare Energy Efficiency | 60–85% Typical overall efficiency range for properly selected positive-displacement systems | Energy consumption depends on pump efficiency, motor efficiency, operating point, pressure losses, and control method. | Compare absorbed power at the duty point, not only the motor nameplate rating. Review the pump curve and calculate energy use per transferred cubic metre. | Operating near the best-efficiency region and avoiding excessive throttling generally lowers power consumption and heat generation. |
| 5 | Verify Suction Conditions and NPSH | NPSH margin: typically 1–3 m Above the pump's required NPSH, subject to manufacturer data | Insufficient suction conditions can cause cavitation, vibration, noise, reduced flow, and premature component damage. | Check suction pipe diameter, length, strainers, oil temperature, tank level, and inlet pressure. Keep the suction route short and avoid unnecessary restrictions. | Use a flooded suction arrangement where practical and avoid operating with a clogged strainer or partially closed suction valve. |
| 6 | Select Compatible Materials and Seals | -20°C to 120°C Common temperature envelope for many petroleum-transfer installations | Material compatibility affects leakage control, service life, contamination risk, and resistance to additives or aggressive fluids. | Confirm compatibility of the casing, rotor or gear components, elastomers, gaskets, hoses, and mechanical seals with the specific oil composition. | For flammable liquids, specify suitable grounding, bonding, electrical protection, and leak-containment provisions in accordance with local regulations. |
| 7 | Evaluate Control, Maintenance, and Safety Features | Continuous-duty design With suitable monitoring and protection | Reliable controls and accessible maintenance points reduce downtime and help prevent dry running, overpressure, overheating, and seal failure. | Look for flow and pressure monitoring, emergency shutdown capability, overload protection, drain points, replaceable wear components, and clear maintenance access. | Track vibration, discharge pressure, motor current, seal leakage, and transfer time to identify efficiency loss or developing faults early. |