As several commonly used types, plunger pumps are important devices in electronic equipment and hydraulic systems. They have various advantages such as high rated pressure, good structure, easy operation, high efficiency, and convenient flow adjustment. So today, I will introduce to you the working principle of the plunger pump, the structure of the plunger pump and how to carry out the daily maintenance of the plunger pump.

How the plunger pump works

The plunger pump is an important device in the hydraulic system. It relies on the reciprocating movement of the plunger in the cylinder to change the volume of the sealed working chamber to realize oil absorption and oil pressure. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency and convenient flow adjustment, and is widely used in high pressure, large flow and flow adjustment occasions, such as hydraulic presses, engineering machinery and ships.

The plunger pump is a kind of reciprocating pump, which belongs to the volume pump. Its plunger is driven by the eccentric rotation of the pump shaft to reciprocate. Its suction and discharge valves are one-way valves. When the plunger is pulled outward, the pressure in the working chamber decreases, and the outlet valve closes. When the pressure is lower than the inlet pressure, the inlet valve opens and the liquid enters; when the plunger is pushed inward, the pressure in the working chamber increases, and the inlet valve closes. When the pressure is higher than the outlet pressure, The outlet valve opens and the liquid is discharged. When the drive shaft drives the cylinder to rotate, the swash plate pulls or pushes back the plunger from the cylinder to complete the oil suction and discharge process. The oil in the working chamber formed by the plunger and the cylinder hole communicates with the suction chamber and the oil discharge chamber of the pump respectively through the oil distribution plate. The variable mechanism is used to change the inclination angle of the swash plate, and the displacement of the pump can be changed by adjusting the inclination angle of the swash plate.

Piston pump structure

Piston pumps are divided into two representative structural forms: axial piston pumps and radial piston pumps; since radial piston pumps are a new type of high-efficiency pump with relatively high technical content, with the continuous development of hydraulic technology, Radial piston pumps will inevitably become an important part of the application field of piston pumps.

Piston pump maintenance

The swash plate axial piston pump generally adopts the form of cylinder rotation and end face flow distribution. A friction pair consisting of a bimetal plate and a steel oil distribution plate is inlaid on the end surface of the cylinder body, and most of them adopt the method of plane flow distribution, so the maintenance is relatively convenient. The oil distribution plate is one of the key components of the axial piston pump. When the pump is working, on the one hand, the high-pressure oil in the working chamber pushes the cylinder to the oil distribution plate; on the other hand, the oil film pressure between the oil distribution plate and the cylinder forms a The hydraulic reverse thrust of the cylinder keeps the cylinder away from the oil distribution plate. The design hydraulic pressure Fn of the cylinder to the oil distribution plate is slightly greater than the hydraulic reverse thrust Ff of the oil distribution plate to the cylinder, that is, Fn/Ff=1.05~1.1, so that the pump works normally and maintains a high volumetric efficiency.