Pump operating on rotational inertial forces with proportional delivery and head inversely proportional to the number of active circuits with the possibility of balancing of the moments of the inertial forces transmitted to the pump supporting frame and generation of rotor oscillatory motion with the pump including a curved tube in the form of a cylindrical ring whose axis coincides with the rotation axis of the rotor to which it is fastened with the tube divided in Nc identical active circuits so as to form with the contribution of the one-way valves Nc/2 2-phase inlet and outlet circuits arranged on opposite faces of the ring with the sum of the deliveries of each inlet proportional to Nc while the pressure developed is proportional to 1/Nc to achieve a pump with very high delivery and relatively low pressure.