Plunger pumps are divided into two types: radial piston pumps and axial piston pumps. The plunger is distributed radially along the circumference (perpendicular to the transmission shaft), which is a radial piston pump. The plunger is distributed along the direction of the transmission shaft (parallel to the transmission shaft), which is an axial shaft plug pump.

Compared with radial piston pumps, axial piston pumps have a higher discharge pressure and can generally operate within the range of 20-50MPa. They also have high efficiency, small radial size, compact structure, small volume, and light weight. But the structure is more complex than that of radial piston pumps, with high processing and manufacturing requirements, and higher prices.