Hydraulic Systems Essentials: Fundamentals of Hydraulic Pumps

The general principle of a hydraulic pump, be it a hydraulic piston pump, gear pump, or another type, is to provide hydraulic energy by using mechanical power to create enough flow to generate the necessary pressure in the system to handle a wide range of useful functions that would otherwise be difficult to perform.

How Does a Hydraulic Pump Work?

A hydraulic pump is designed to perform two basic functions when in operation. It starts by creating a vacuum to draw hydraulic fluid into the pump through the pump inlet. This function then causes the fluid to flow out of the pump outlet and into the hydraulic system.

The pump’s primary purpose is to create flow by introducing the hydraulic fluid into the system. The pump does not create pressure, but, rather, the resistance to the fluid in the system generates the pressure.

The pressure will continue to increase as resistance increases until the systems overcomes the resistance to perform the desired function, such as lifting a heavy object using a forklift.

Hydraulic Pump Classifications

There are two general classifications used to describe how a hydraulic pump operates. These are positive displacement pumps and non-positive displacement pumps. When selecting pumps for various job functions, it is essential to know the differences between the two.

With a positive displacement pump, flow is delivered at the same rate into the system. This is why these pumps are also called fixed displacement pumps. If you were to plug the output port and turn the pump on, the resistance to the flow would continue to increase until the pump failed or blew up.

With a non-positive displacement pump, the flow rate will decrease when there is an increase in resistance due to slippage. If you were to plug the output port on this pump, the flow would drop to zero from slippage even though the pump would keep running.

For further information about hydraulic pumps, hydraulic systems, or assistance in selecting the right pumps, parts, and components, please feel free to contact White House Products, Ltd. at +44 (0) 1475 742500 today!