There are typically three types of Hydraulic Pump china hydraulic pump constructions found in mobile hydraulic applications. These include equipment, piston and vane; however, additionally, 
there are clutch pumps, dump pumps and pumps for refuse automobiles such as dry valve pumps
The hydraulic pump is the element of the hydraulic system that takes mechanical energy and converts it into fluid energy in the form of oil flow. This mechanical energy is definitely taken from what is called the primary mover (a turning drive) such as the power take-off or straight from the 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 direction of shaft rotation. However, a bi-rotational pump has the ability to operate in either direction.