Ring 1 rotates about fixed axis A, eccentrically located with respect to the geometric axis of housing 4. Ring 1 has slots in which vanes 2 and 3 slide. Vanes 2 and 3 have slots a which envelope axis A. When ring 1 rotates, vanes 2 and 3 deliver liquid in the direction of the arrows.
$3800$LHP,RP$