Variable displacement pump's control style has many ways, such as constant pressure, constant fluid, constant power, electrohydraulic proportional and load-sensing etc.
The hydraulic system with variable displacement pump-constant displacement motor has the function of overload protection.
It is a vane pump with high head, small flow and low specific speed, which is smaller, flight and simpler in structure than positive displacement pump mulfistage centrifugal pump, and may handle liquid of high gas or steam content.