What is the difference between axial flow pumps and piston pumps?

Axial pumps: Drive pulley and piston are not in a fixed connection. The pistons are pressed against the drive pulley by means of a return spring. Pump runs much more unsteadily with self-priming.

Piston pumps: Connecting rods and pistons are positively controlled, as they are permanently bolted to the crankshaft. This results in smoother running and furthermore the piston pumps are also more suitable for direct water suction. Piston pumps are ideal for long-lasting and durable use.