Abstract: A rotary pump has a housing providing an annular passageway in which vanes carried by a rotor move in a circular path. The vanes are in the form of circular discs on the outer ends of radial shafts rotatably mounted in a hollow hub portion of the rotor. The annular passageway of the housing has a pumping portion of circular cross section with a diameter equal to that of the vanes and a sealing portion having a cross section corresponding to the cross section of the vanes. The angular orientation of the vanes is cyclically controlled so that the vanes are orthogonal to the passageway when in the pumping portion and are in line with the passageway when in the sealing portion. Control is effected by means of two separate rollers on an eccentric inner extension of each of the vane shafts. One roller engages a stationary annular cam coaxial with the rotor axis.