Abstract: A fluid handling device capable of being used for numerous purposes, including use as an internal combustion engine or as a fluid pump, compressor, or expander, which fluid handling device is characterized in its preferred embodiments by: (a) a body with a spherical plenum; (b) a spherical member (which is located within said plenum); (c) two vane members lying in the same plane on opposing sides of said sphere exterior to said spherical plenum (which vane members have side edges that are perpendicular to the surface of said sphere); and (d) two cavities shaped like equilateral triangles with outwardly arcing walls on opposing sides of said sphere (the apex of one such triangle being positioned opposite the base of the other).