Types of Hydraulic Pumping
In hydraulic machinery, the pump is used to increase fluid pressure from its source. Pumps can be classified into different main categories. The most common types of hydraulic pumping include:
Positive Displacement Pumps
Positive displacement pumps are used for applications that require high-pressure delivery that comes with low pulsation. To build up enough pressure, you have to move a piston or diaphragm many times along its axis so that there is space for little or no fluid at any given time during pumping action. Positive displacement pumps are typically sized by how much they can produce per revolution rather than by flow rate.
Gear pumps are used for moderate pressure applications and have more pulsating flow than constant ones. The pumps use two meshed gears to transfer fluid from the inlet to the delivery side. The gears rotate around the same axle with one gear rotating clockwise and another counter-clockwise so that as one rotates, it presses on fluid inlets causing them to expel their contents into the space between the gears where the other gear will press it back towards an outlet with its rotation and also pressurize any fluids caught between them.
Vane pumps use a series of thin metal blades (vanes) that rotate around inside a cylindrical chamber, pushing fluid into and out of it as they go past inlet and outlet ports. The hydraulic pumping is typically quieter than other types and can handle high pressures, but they need more maintenance than most other pumps, and their performance depends on how well they have been lubricated.
Pumps centrifugal pumps are the most common type in the industry today. They operate by drawing fluid into an impeller, a rotating disk that throws it out at high speed against the walls of a casing. This action creates a pressure difference between the inlet and outlet that causes the fluid to flow through the pump. Centrifugal pumps are tolerant to many fluids, can handle high pressures and flow rates, and are relatively cheap.
Each type of hydraulic pumping has its specific uses and advantages, and the most appropriate type for a certain application depends on how much fluid needs to be moved and what kind of force is needed.