Patent ID: 8191383

Claim:
An ejector device comprising a nozzle configured to decompress and expand refrigerant, the nozzle having an inner wall surface defining a fluid passage extending from an inlet to a jet port of the nozzle, and a suction port from which refrigerant is drawn by using a jet flow of the refrigerant jetted from the nozzle; wherein the fluid passage is a circular shape in a cross section perpendicular to an axial line of the fluid passage, the fluid passage has a throat portion at a position between the inlet and the jet port, at which a cross-sectional area of the fluid passage becomes smallest, and a passage expanding portion in which the cross-sectional area of the fluid passage is enlarged from the throat portion as toward downstream to decompress a fluid flowing into the throat portion, and the passage expanding portion includes a middle portion in which the inner wall surface is expanded in a fluid flow direction by a first expanding angle, and an outlet portion from a downstream end of the middle portion to the jet port, in which the inner wall surface is expanded in the fluid flow direction by a second expanding angle that is larger than the first expanding angle.