Patent ID: 8282025

Claim:
An ejector comprising: a nozzle configured to decompress and expand a fluid and to jet the fluid from a fluid jet port; and a body provided with a fluid suction port from which a fluid is drawn by a high-speed jet fluid jetted from the fluid jet port, and a pressure increasing portion in which a velocity energy of a mixture fluid between the jet fluid and a suction fluid drawn from the fluid suction port is converted to a pressure energy thereof, wherein an inner peripheral surface of the nozzle defining a fluid passage includes a throat portion in which a fluid passage sectional area of the fluid passage is most reduced, a first taper portion arranged downstream of the throat portion to gradually enlarge the fluid passage sectional area as toward a flow direction of the jet fluid, a second taper portion arranged downstream of the first taper portion to gradually enlarge the fluid passage sectional area as toward the flow direction of the jet fluid, and an end taper portion arranged in a range from an outlet side of the second taper portion to the fluid jet port, to gradually enlarge the fluid passage sectional area as toward the flow direction of the jet fluid, when an axial cross section including an axial line of the nozzle is defined as a standard cross section, a second expanding angle at an outlet side of the second taper portion on the standard cross section is larger than a first expanding angle at an outlet side of the first taper portion on the standard cross section, and an end expanding angle at an outlet side of the end taper portion on the standard cross section is smaller than the second expanding angle.