Rotary Pump, anonymous, c. 1850 - c. 1858 test model Rotation pump on the suction and pushing principle, consisting of a cylindrical drum with a supply and output pipe and a crank. Inside the drum is not cylindrical but heart -shaped. A large cylinder in the middle touches the inner wall where the inward point of the heart is. A slat is installed in the cylinder, which protrudes through a slot in the cylinder wall and serves as a piston. Cylinder and piston are turned around a central heart -shaped core with the crank that controls the movement of the piston so that it always forms a wall between cylinder and inner wall of the drum. If cylinder and piston are turned around, the space between the cylinder and the inner wall of the drum is divided into two rooms by the piston, which differ in size depending on the position of the piston. For example, a room is created during the supply that is getting bigger and thus sucks in, and when the piston subsequently comes back to the supply, th