Determining the gear pump efficiency is all about comparing energy output to energy input as a percentage. Here’s how you can calculate it;
- Measure Input Power (P_in): The electric motor or internal combustion engine provides the power input in most cases to the gear pump. This could be measured in kilowatts or horsepower. It can be done by either using a power meter or mathematically calculating it using electrical motor P_in = VIPF/1000 where P_in is in kW, V is volts, I is the current provided and PF.
- Measure Output Power (P_out): The output power is what the pump does that can be used. This is determined by multiplying together the fluid flow rate Q (usually gallons per minute or liters per minute) and total differential pressure ΔP (pounds per square inch or bar). This formula reads: Pout (kW) = Q × ΔP / 1714 for measurements in US customary units and Pout (kW) = Q × ΔP / 600 for measurements in metric units with conversion factors that allow flow and pressure to be expressed as per kilowatts.
- Calculate Efficiency(η): From both powers now known, one can calculate efficiency as shown below η (%)=(Pout/Pin)*100
An example of the step-by-step process is provided below:
- Assuming 5 kW is the electric motor power input to the gear pump (P_in).
- The gear pump output which is measured in hydraulic power (P_out), turns out to be 4 kW.
- Efficiency formulae should be used: η (%) = (P_out / P_in) × 100 = (4 kW / 5 kW) × 100 = 80%.
Therefore, the efficiency of this gear pump is 80% meaning that 20% are wasted through friction, leakage and other inefficiencies within the pump while the rest become hydraulic energy.
For accurate measurement, one must ensure that their measuring instruments have been properly calibrated and that they operate within their intended working range for them. Additionally, when measuring efficiency of a machine it’s important to take both input and output powers under similar operating conditions so as to get correct calculations.
