What is Hydraulic Pump : Construction, Working & Its Applications

The hydraulic pump is an essential component in the hydraulic system that uses mechanical energy from the engine to convert it into fluid energy. Hydraulic systems are mainly designed for transmitting power in a controlled way through pressurized liquids. In hydraulic systems, the pressure is created by the design of applied forces as well as the measure of pipes. Smaller pipes in these systems will increase the pressure & resistance. So this article discusses an overview of a hydraulic pump – working with applications.

What is a Hydraulic Pump?

A hydraulic pump can be defined as; a type of pump or mechanical power source used to change mechanical power into hydraulic energy like pressure or flow in hydraulic drive systems & hydrostatic or hydrodynamic systems. This pump generates flow with sufficient power to conquer force induced by the load at the outlet of the pump. This pump is used in most heavy construction vehicles within a hydraulic system and is also utilized for powering hydraulic tools like hydraulic spreaders, jacks, hydraulic saws, nut splitters, cutting tools, pressing machines, etc.

How Does a Hydraulic Pump Work?

Once a hydraulic pump operates then it performs simply two functions. The first function is, that its mechanical action creates a vacuum at the inlet of the pump which permits atmospheric force to push the liquid from the tank into the inlet of the pump. The second function is, that its mechanical act transports this liquid toward the outlet of the pump & forces it to move into the hydraulic system.
A hydraulic pump generates movement of liquid or flow then it does not generate force. But it generates the required flow for the development of force which is a function of resistance to liquid flow within the system.

Construction of Hydraulic Pump

The hydraulic pump assembly diagram is shown below. These pumps include numerous mechanical moving components that get energy from any other source. Most hydraulic pumps include rotary parts that activate by the electrical source. The essential components used in these pumps are discussed below.

Hydraulic Pump Construction
Hydraulic Pump Construction


The casing is the external part of the pump which protects the inside components of the pump. These pumps are constructed with either aluminum or cast iron materials.


Impeller Blades

Impeller blades simply rotate in the housing of the pump. These blades help in rotating the surrounding fluids so that the flow of fluid will be at a higher potential. In addition, they play a significant role in cooling & lubricating the system.


The shaft of the hydraulic pump is utilized to mount the impeller. This shaft is made with stainless steel or steel and its size mainly depends on the impeller.

Bearing Assembly

Bearing assembly helps in rotating the impeller continuously. Most of the pumps use ball-type anti-friction bearings.


Bearing assemblies in most of the pumps fail then pumps will get damaged. So, sealing is used to eliminate the failure risk by shielding the bearing assemblies from coolants & contaminants.


A hydraulic pump carries any fluid from the tank or reservoir to other system parts. The inlet & outlet of this pump includes check valves which are arranged at the inlet of the pump to push the fluid from the reservoir or tank into the pump & the outlet will force fluid to supply to the remaining parts of the system. Here, the fluid at the inlet is pushed through the vacuum created. A gas engine or electric motor is used as the prime mover for rotating the shaft. The impeller blades are arranged on the shaft & the nearby fluids will turn with the shaft’s movement.

Once the piston is pulled then a vacuum is formed within the cylinder. So this vacuum will close the outlet valve & open the inlet valve of the pump. After that, the fluid from the reservoir enters the pump & fills the cylinder partially. Once the piston is pulled, then molecules of fluid will approach closer & the inlet valve will close and the outlet valve will open to flow the fluid throughout it.

Types of Hydraulic Pumps

There are different types of hydraulic pumps which are discussed below.

Vane Pump

These are positive displacement hydraulic pumps that maintain a stable flow rate at varying pressures. This type of pump includes a variable no. of vanes placed onto a rotor that turns in the cavity and also a pressure relief valve that avoids an increase in pressure within the pump from harming it. Vane pumps operate at extremely low noise levels with a constant flow rate. These pumps generate less noise while maintaining a high speed of up to 3,000 rpm.

Hydraulic Vane Pump
Hydraulic Vane Pump

Hydraulic Gear Pump

These pumps are available in two types Internal & external gear pumps. External gear pumps include two spur gears that are arranged externally whereas internal gear pumps include two spur gears that are arranged internally. These types of gear pumps are used for delivering a consistent amount of fluid through each rotation of the gears.

Gear Pump
Gear Pump

These pumps are very famous due to their simple design, effectiveness, versatility, and accessibility in different configurations, so they are used in different industrial, consumer, and commercial product-based applications.

Hydraulic Ram Pump

These are commonly used hydraulic pumps which are used for supplying water in the agricultural, plumbing, waste management, sewage, manufacturing & engineering industries. These pumps work by using hydropower rather than an external energy source. So these pumps are a prominent choice in some developing countries where the accessibility of the electricity & fuel necessary to strengthen motorized pumps is restricted. The hydropower usage will also decrease energy utilization for plants & industrial factories.

Hydraulic Ram Pump
Hydraulic Ram Pump

Electric Hydraulic Pump

These are hydraulic liquid transmission pumps that work by using electricity. These pumps are normally utilized to move hydraulic liquid from a tank to a hydraulic cylinder. There are different hydraulic pumps there, but the defining characteristic of every type is the utilization of pressurized fluids to complete a job.

Electric Hydraulic Pump
Electric Hydraulic Pump

These pumps are powered by electricity. Once an electric current is supplied throughout the motor then it activates the impellers otherwise other devices in the pump system make differences in pressure. So these differential pressure levels allow fluids to supply throughout the pump. These pumps are used to direct hydraulic fluid to industrial machines like excavators or elevators.

Hydraulic Hand Pump

These are fluid transmission machines that use the mechanical power produced by a physically operated actuator. Here an actuator could be a toggle, lever, handle, etc. These pumps are used for water pumping, hydraulic fluid distribution, etc. These pumps are used for different tasks like the direction of hydraulic liquid to circuits within helicopters, instrument calibration & piston actuation within hydraulic cylinders.

Hydraulic Hand Pump
Hydraulic Hand Pump

Every hydraulic hand pump includes an actuation handle or lever connected to the pump. Once this handle is pushed or pulled, then it causes the hydraulic fluid within the pump’s system to be pressurized or depressurized. So this action in the pump provides power to the attached devices to the pump.

12V Hydraulic Pump

Hydraulic pumps operate on a 12V DC supply through a battery/motor o move water into or out of the preferred location. These pumps are normally used to push, pull & also lift heavy loads within motorized & vehicle machines. These hydraulic pumps are very common as they work on small batteries.

12V Hydraulic Pump
12V Hydraulic Pump

Air Hydraulic Pump

These pumps are also known as pneumatic hydraulic pumps which use compressed air to activate a pump mechanism and generate energy from a pressurized fluid. These pumps are used in different industries to help in the lifting of heavy loads & transportation of materials through minimal initial force.

Air Hydraulic Pump
Air Hydraulic Pump

Hydraulic Piston Pump

Hydraulic piston pumps are used to transfer hydraulic fluids throughout a cylinder using the plunger to increase the pressure for a machine by allowing it to lift, push & pull heavy loads. These pumps are used as the power source for heavy-duty machines such as backhoes, excavators, loaders, cranes & diggers. These types of pumps are mainly utilized in different industries like aeronautics, automotive, military, power generation, manufacturing & marine.

Piston Pump
Piston Pump

Hydraulic Clutch Pump

These pumps include a clutch assembly that allows the user to apply the required pressure to engage or disengage the clutch mechanism. These clutches are crafted to link two shafts & lock them jointly to turn at the same speed otherwise separate the shafts & let them turn at various speeds when required to slow down or shift gears.

Hydraulic Clutch Pump
Hydraulic Clutch Pump

Difference between a Hydraulic Pump and Hydraulic Motor

The difference between a hydraulic pump and a motor is discussed below.

Hydraulic Pump

Hydraulic Motor

It is a conversion device used to change the motor’s mechanical energy into hydraulic energy. A hydraulic pump is one type of conversion device used to convert the energy of liquid pressure into mechanical & provides torque & speed.
This pump includes a large oil suction & tiny oil discharge port. This motor includes a small oil suction & oil discharge port.
The working speed of this pump is high. The working speed of this motor is low.
Pumps operate in a single direction/ Motors operate unidirectionally.
The volumetric efficiency of this pump is high. The volumetric efficiency of this motor is low.
The internal leakage of this pump is small. The internal leakage of this motor is large.
The vane of this pump is installed diagonally. The vane of this pump is installed radially
This pump doesn’t need a vacuum within its low-pressure chamber. This motor has a vane within its low-pressure chamber to ensure that it is efficient or not at the absorption of oil.
These pumps have a small start-up torque. These motors have large start-up torque.
These pumps are available in different types like rotary vane, piston & screw. These motors are available in two types piston & plunger and vane & gear.


The advantages of a hydraulic pump include the following.

  • These pumps are energy efficient.
  • The speed & flow of these pumps are managed & monitored very easily as compared to any other types of pumps.
  • Less maintenance cost.
  • Hydraulic pumps are accurate and very easy to control.
  • It delivers stable force or torque when speed changes.
  • Leakages can be discovered easily.
  • These do not cause any sparks, thus these pumps are used very safely within mines & chemical plants.
  • Reduces unwanted noises.


The disadvantages of hydraulic pumps include the following.

  • Hydraulic liquids handling & repairing leaks within this pump is hard.
  • Hydraulic pump failure can cause due to many reasons like contamination of fluid, viscosity issues of fluid, excess heat, implosion, aeration, cavitation, and over-pressurization.
  • These pumps need maintenance.
  • A small leak within this pump can cause damage.
  • The risk of accidents will be increased.
  • Work accidents can be caused due to the high pressure obtained by fluid c if the power is very high & the pipeline is not capable to resist the power delivered through the fluid.


The applications of hydraulic pumps include the following.

  • Hydraulic pumps are utilized on industrial hydraulic machines.
  • These are used on cranes, excavators, loaders, vacuum trucks, tractors, forestry equipment, dump trucks, graders, mining machinery, and many more.
  • These are used in mobile applications more prolifically than industrial machines.
  • These are still extensively used in industrial environments.
  • Hydraulic pumps are combined with jacks & engine hoists within the automotive industry for lifting vehicles, heavy loads, platforms & pulling engines.
  • These are used in mechanical workshops to power tools for drilling, cutting, pulling, pressing, etc.
  • These are used in splitters of wood workshops.
  • These are utilized in vehicular machines like cranes, excavators, tractors & loaders.
  • They are used in production services like forklifts, mixers, conveyors, etc.
  • Hydraulic Pump Construction
  • The hydraulic pump assembly diagram is shown below.

Thus, this is an overview of hydraulic pump – types, working with applications. These pumps are mainly designed to use in industrial, residential, and commercial areas to produce useful energy from the pressurization of different viscous liquids. Hydraulic pumps are very simple & effective machines used for moving fluids. These pumps mainly depend on the energy given by hydraulic cylinders to control different machines and devices. Here is a question for you, what is an alternate name for a hydraulic pump?