Piston pumps are a special branch of volumetric pumps, which exploit the variation of volume inside a chamber in order to cause a given fluid to be suctioned or pushed out. The flow rate of the pump is independent of the head and is directly proportionate to the rotation speed. As far as the piston pumps designed by Leuco S.p.A., sold under the "Hawk ® International" brand, are concerned, the variation in volume is the result of the alternated sliding of a piston inside a special cylinder, in which special check valves force the contained fluid through in a given direction, preventing it from flowing back as the piston returns.
There are various different types of piston pumps, also known as plunger pumps, which can be divided according to their effect. Single effect piston pumps are those which work only as the piston moves in one direction, while double effect piston pumps work in both directions, as the piston moves forwards and then back. But the empirical division of the different types of HAWK piston pumps concerns a different category, which divides pumps into suction and pressing. In the case of suction pumps, the piston sliding inside the cylinder creates a vacuum which lifts the liquid into a pipe and expels it from the pump at ambient pressure. On the other hand, in pressing piston pumps the fluid enters the cylinder at ambient pressure and is lifted by pressure. In this case the cylinder is at the same level or below the liquid to be lifted. In fact there is also a third type of piston pump, produced by Leuco, which integrates both functions, pressing and suction, in a single pump.
Leuco S.p.A., based in Reggio Emilia, has been designing and building piston pumps for different uses for more than thirty years: they are installed in applications which run from high pressure water cleaners for civil and industrial use to self-service car wash systems, where the piston pumps are applied to a special gun for car washing. The wide range of piston pumps produced by Leuco S.p.A. and sold under the HAWK brand includes more than 70 models, and is therefore able to satisfy an increasingly wide range of customers in Italy and, above all, abroad, where the quality and accuracy of the components used to produce HAWK piston pumps assures their reputation among the best in the world.