Hydraulic pumps are key to the function of heavy and compact equipment, but sometimes the terminology applied to hydraulic pumps can be confusing. How much do you know about hydraulic pump applications? Zhejiang Yongling Hydraulic Machine Co , Ltd . elaborated on the pressure and rated efficiency of Hydraulic Pumps .
Does the hydraulic pump generate pressure?
The fluid flow produced by the pump generates pressure only when it encounters resistance. If the pump is not connected to the system, the pressure at the pump outlet will be zero because there is no resistance to prevent fluid flow. This lack of pressure has led many engineers to point out that the pump does not generate pressure.
There are some good arguments for pressure rather than fluid flow. When modeling the pumps in the system, it has been found that it is more accurate to model the pump as a pressure source rather than a flow source.
What is the rated pressure of a hydraulic pump?
The hydraulic pump has a rated pressure. Rated pressure is the pressure that the pump can withstand before it begins to leak or suffer damage. Another way to look at it is that the rated pressure represents the pressure at which the pump can maintain countercurrent flow. Therefore, you need to ensure that the pump's rated pressure is lower than the system pressure to be used.
Hydraulic pumps: What is the difference between volumetric efficiency, mechanical efficiency and overall efficiency?
Hydraulic pumps have at least three different measures of efficiency: volumetric, mechanical, and monolithic. Volume efficiency is the actual flow rate at a given pressure divided by the theoretical flow rate. The actual flow is measured using a flow meter, while the theoretical flow is determined by multiplying the pump's drive speed (in rpm) by the pump's displacement per revolution. Volumetric efficiency is a good way to feel pump performance and can be used to estimate pump performance in the field.
Mechanical efficiency, also known as hydraulic efficiency, is the theoretical torque required to drive a pump divided by the actual torque required to drive the pump. Total efficiency is the product of volumetric efficiency and mechanical efficiency. The overall efficiency of most axial piston motors is about 91%.
What is the difference between head and pressure?
This can cause some confusion when the pump is rated by head rather than pressure. There is a very simple formula to switch between head and pressure: pressure (psi) = head (ft) /2.31 or head (ft) = 2.31 x pressure (psi). The use of the head was derived from the work of Greek mathematician and scientist Archimedes and his innovative screw pump design.