1, according to the flow is adjustable can be divided into: variable pump and dosing pump.
The output flow can be adjusted according to the needs of the variable pump, the flow can not be adjusted called the quantitative pump.
2, according to the hydraulic system commonly used pump structure is divided into: gear pump, vane pump and plunger pump 3 kinds.
Gear Pump: Small size, simple structure, the cleanliness of the oil requirements are not strict, the price is cheaper, but the pump shaft by unbalanced force, serious wear, leakage is large. Vane pump: Divided into double-acting vane pump and single-acting vane pump.
This pump flow uniformity, smooth operation, low noise, pressure and volumetric efficiency than gear pump, structure than gear pump complex.
PLUNGER Pump: High volume efficiency, small leakage, can work under high pressure, mostly used in high-power hydraulic system, but the structure is complex, the material and processing precision requirements are high, the price is high, the oil cleanliness requirements. Generally in the gear pump and vane pump can not meet the requirements of the plunger pump.
There are other types of hydraulic pumps, such as screw pump, but the application is not as common as the above 3.