One way to determine if a hydraulic pump needs replacing is to calculate its efficiency.
Hydraulic pumps with low efficiency not only cause the performance of the entire system to decline, but also pose potential financial and safety risks.
Sometimes when hydraulic equipment slows down significantly, it may not be necessary to calculate the pump's efficiency before replacing it.
However, in other cases, comparing the actual efficiency of the pump with its theoretical efficiency can be useful.
1. What are the different hydraulic pump efficiency categories?
Hydraulic pump efficiency can be divided into three categories: volumetric efficiency, mechanical efficiency or hydraulic efficiency, and overall efficiency.
(1) Volumetric efficiency
Volumetric efficiency is typically the most commonly used type of efficiency. Evaluates the condition of the hydraulic pump based on its internal leakage. Volumetric efficiency considers the hydraulic oil pumped by the pump compared to the theoretically expected hydraulic oil production.
Before calculating the volumetric efficiency, it is necessary to know the theoretical flow of the pump by multiplying its displacement by the drive speed.
- Theoretical flow = Displacement per revolution X Driving speed
Once you understand the theoretical flow rate, you can use a flow meter to calculate the actual flow rate, and then divide the actual flow rate by the theoretical flow rate to obtain the volumetric efficiency of the hydraulic pump.
- Volumetric efficiency = (Actual flow / Theoretical flow)
(2) Mechanical/hydraulic efficiency
Mechanical efficiency compares the actual torque required to drive the pump with its theoretical torque.
- Mechanical/hydraulic efficiency = (Theoretical torque / Actual torque)
If the mechanical efficiency is 100%, it means the hydraulic pump can provide flow without requiring any torque at zero pressure. However, in reality this is impossible due to mechanical and fluid friction.
(3) Overall efficiency
The total efficiency is obtained by multiplying the other two efficiencies. You can use overall efficiency to calculate how much driving force a hydraulic pump needs at a given flow rate and pressure. For the same flow rate and pressure output, higher efficiency pumps will obviously require less energy, and lower efficiency pumps will lose more energy as heat.
2. When should a hydraulic pump be replaced?
If the efficiency is very low, the hydraulic pump must be replaced. Ignoring or failing to identify signs of hydraulic pump failure is unsafe and can result in other costly losses.
In addition to calculating the efficiency of the hydraulic pump, there are some warning signs that may indicate that it is time to replace the hydraulic pump:
(1) The pump makes loud noises;
(2) Internal leak;
(3) External leak;
(4) High operating temperature.
