There are typically three types of hydraulic pump constructions within mobile hydraulic applications. These include gear, piston and vane; however, additionally, there are clutch pumps, dump pumps and pumps for refuse vehicles such as for example dry valve pumps
The hydraulic pump may be the component of the hydraulic system that takes mechanical energy and converts it into fluid energy in the form of oil flow. This mechanical energy can be taken from what is called the prime mover (a turning push) like the power take-off or directly from the pickup truck engine.
With each hydraulic pump, the pump will be of either a uni-rotational or bi-rotational design. As its name implies, a uni-rotational pump 
is designed to operate in one path of shaft rotation. However, a bi-rotational pump has the ability to operate in either path.