We can consider hydraulic pump as a heart of any hydraulic system used. Every hydraulic system requires high-pressure incompressible fluids for generating force. A hydraulic pump plays an important role in converting the mechanical energy to hydraulic energy. You can find different varieties of pumps in the market. It will differ depending on the size, shape, and method of operation. A pump can be operated either manually or mechanically. Hydrodynamic(non-positive displacement) and hydrostatic(positive displacement) are the two classifications of the hydraulic pump.
Hydraulic pumps are used for low-pressure high volume applications. These pumps will force the low-pressure fluid to flow at a higher speed and result in the flow of high volume fluid in minimum time. How hydraulic pump works? You can learn the basic details on the working principle of hydraulic pumps from this article.
In hydrodynamic pumps, the fluid weight and the friction are the resistance encountered and the pump operate using centrifugal force. The rotating impeller blades of hydrodynamic pumps will throw the fluid entering at the center of the pump housing to the outlet. They are used for creating a smooth continuous flow, but the resistance encountered will inversely affect the performance.
Also Read: Hydraulic Pumps: The ultimate guide for beginners
Construction of Hydraulic Pump
Hydraulic pumps are used for energizing fluids to flow from a lower potential to higher. It has several mechanical moving components that receive energy from any other source(mainly electrical). Most of the hydraulic pumps have rotating parts that operate using the electrical source. The basic components used in hydraulic pumps are:
Pump Housing/Casing: This is the exterior part of the hydraulic pump to protect the inner components. Smaller pumps use aluminum as the construction material and others use cast iron.
Impeller Blades: The impeller blades will rotate inside the pump housing. The rotation of impeller blades will rotate the surrounding fluids and thus the fluid flow at a higher potential. Also, they play an important role in lubricating and cooling of the system.
Pump Shaft: Pump shaft is used to mount the impeller. Steel or stainless steel are used for constructing the shaft and the size will depend on the impeller.
Bearing Assembly: Assistance for continuous impeller rotation is the function of pump bearings. Most of the centrifugal pump uses standard ball-type anti-friction bearings.
Sealings: Most of the pumps fail due to the damage of bearing assemblies. Seals will eliminate the risk of failure to a greater extent by protecting the bearing assemblies from contaminants and coolants.
Hydraulic Pump Working
Hydraulic pump will carry oil or any other fluids from the reservoir/tank to other parts of the system. The working of the hydraulic pump is based on displacement principle(Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object).
Both the inlet and outlet of the hydraulic pump contains different check valves. The check valve located at the inlet will push the fluid from the tank/reservoir into the pump and the one located at the outlet will pump fluid to other parts of the system.
The vacuum created will push the fluid into the pump inlet. Electric, motor or a gas engine are used as the prime mover to rotate the shaft. The impeller blades located on the shaft and the surrounding fluids will rotate with the movement of the shaft.
A vacuum is created inside the cylinder when the piston is pulled. The vacuum created will close the outlet check valve and open the inlet check valve. Then, fluid from the tank or reservoir enter into the pump and partially fills the cylinder. When the piston is pushed, the fluid molecules will come closer and the inlet check valve will close. This will open the outlet check valve and fluid flows through it.