Axial pumps are intended mainly for the supply of large volumes of liquids. Their work is due to the transfer of the energy that the liquid receives when the frontal surface of the rotating blades of the impeller is forcefully exposed to it. At the same time, the particles of the supplied liquid have curved trajectories, but after passing through the straightening apparatus, they begin to move from the entrance to the pump to the exit from it, mainly along its axis (hence the name). There are 2 main types of axial pumps: rigid-bladed with blades fixed motionlessly on the impeller sleeve, called propeller, and rotary-bladed, equipped with a mechanism for changing the angle of inclination of the blades. Pumps of both varieties are usually built single-stage, less often two-stage. A distinctive feature of axial pumps is the design and operation of the impeller. It consists of a sleeve on which several blades are fixed, representing a conveniently streamlined curved wing with a twisted front edge running into the flow. When the blade profile is moved, caused by the rotation of the impeller, in the liquid, due to a change in the velocity of its flow along the lower and upper surfaces of the profile, the pressure above the profile should increase, and under the profile - decrease. This creates a pump head.