A short introduction to Hydraulic Pump types
With the introduction of modern machinery, a need for a flexible and efficient way to transfer energy has driven innovations into hydraulics. The hydraulic pump technology is often the preferred choice due to its efficiency and simplicity and is the source of power for a plethora of dynamic machines such as excavators, cranes, loaders, tractors, vacuum trucks, forestry equipment, graders, dump trucks, mining machinery etc.
In this article, we’ll give you a short introduction to different types of common hydraulic pumps and their features. But first,…
What is a hydraulic pump?
A hydraulic pump is a mechanical device that converts mechanical power into hydraulic energy. When a hydraulic pump operates, it creates pressure that causes hydraulic cylinders in the units to extend and retract.
Classifications of pumps
Non-positive-displacement pumps produce a continuous flow. However, since it doesn’t provide a positive internal seal against slippage, the output varies depending on pressure variations. Examples of non-positive-displacement pumps include:
- Centrifugal pumps
- Propeller pumps
In contrast to the non-positive-displacement pumps are the positive-displacement pumps where slippage is negligible compared to the pump’s volumetric output flow. They can either be of fixed or variable displacement.
A fixed pump’s output remains constant during each pumping cycle and at a given speed. The output of a variable displacement pump can be changed by altering the geometry of the displacement chamber and is particularly suited in circuits using hydraulic motors where variable speeds or the ability to reverse is needed.
Variable displacement pumps are especially useful since they can provide infinite adjustment of the speed range. Examples of positive-displacement pumps include:
- Axial piston pumps
- Internal gear pumps
- External gear pumps
- Radial piston pumps
- Rotary vane pumps
The most common types of variable hydraulic pumps
A hydraulic pump is any class of a positive-displacement machine used in fluid power application to provide a hydraulic flow to fluid-powered devices (cylinders, rams, motors, etc.).
Hydraulic pumps are used within a wide range of engineering fields and are available in a plethora of different designs. Each type of pump has a different internal mechanism based on the same fundamental principles. Let’s take a look at some of the most common types of variable hydraulic pumps.
Axial piston pumps
Axial piston pumps are, as the name suggests, axially mounted pistons that reciprocate within internal cylinders to create alternating suction and discharge flow. They can be designed as variable-rate devices to control the speeds of hydraulic motors and cylinders.
Radial piston pumps
Radial piston pumps have an arranged series of pistons radially around a rotor hub. The rotor forces the pistons in and out as it rotates. This causes the hydraulic fluid to be sucked into the cylinder cavity and then be discharged from it. The inlets and outlets are located in a valve in a central hub.
Rotary vane pumps
Rotary vane pumps use a series of rigid vanes which are mounted in an eccentric rotor. The rotor sweeps along the inside wall of a housing cavity, creating smaller volumes which forces the fluid out through the discharge port.
External gear pumps
External gear pumps rely on the counter-rotating motion of meshed external spur gears to impart motion on the fluid. External gear pumps are usually fixed-displacement design and are both very simple and robust.
Internal gear pumps
Internal gear pumps use the meshing action of both an internal and external gear combined with a crescent-shaped sector flow to impart motion on the fluid.
Get your hydraulic pump accessories at Bygging-Uddemann
When it comes to choosing and purchasing your hydraulic pumps and motors, you need a reliable partner that will offer you the best solutions. You also need a partner that offers a range of pumps so that you can choose the one that best suits your needs.
With many years of experience and technical expertise, we offer different types of only the highest-quality hydraulic high-pressure oil pumps and their accessories. The pumps are robust, easy to use, and they get the work done with the highest degree of precision and efficiency.
Contact Bygging-Uddemann today for more information.
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