Tuthill's L Series Lubrication Pumps

Tuthill L Series cast iron pumps employ the internal gear pumping principle. There are only two moving parts. The pumping action is based on a rotor, idler gear, and a cover cast with a crescent-shaped partition. Power applied to the rotor is transmitted to the idler gear with which it meshes. The space between the idler’s outside diameter and the rotor’s inside diameter is sealed by the crescent. As the pump starts, the teeth come out of mesh, increasing the volume. This creates a partial vacuum, drawing the liquid into the pump through the suction port. The fluid fills the spaces between the teeth of the idler and the rotor and is carried past the crescent partition through the pressure side of the pump. When the teeth mesh on the pressure side, the liquid is forced from the spaces and out through the discharge port.