Abstract: A rotodynamic fluid machine comprising a plurality of separate coaxial cylindrical chambers in each of which a drive rotor is positioned. The drive rotors mesh with corresponding sealing rotors and have blades that are curved in such a manner so that if the rotors are placed in abutting relationship that the blades on one rotor will mate with the contiguous blades of the other rotor and extend around the circumference of the rotor so as to overlap in a circumferential direction.