Patent ID: 6966199

Claim:
An ejector comprising: a nozzle for defining therein a passage through which a drive fluid flows, the nozzle including a throat portion having a cross-sectional area that is smallest in the passage of the nozzle; a pressure-increasing portion in which a fluid is sucked by entraiment of a jet flow of the drive fluid injected from the nozzle and is mixed with the drive fluid injected from the nozzle; and an adjustment unit that is disposed to adjust both an opening degree of the throat portion and an exit opening of an outlet of the nozzle; wherein the adjustment unit includes a needle valve that extends along a flow direction in the nozzle at least from the throat portion to the outlet of the nozzle in a manner that a distal end of the needle valve protrudes from the outlet of the nozzle, and an actuator for moving the needle valve in its axial direction to adjust the opening degrees of both the throat portion and the outlet of the nozzle; and the needle valve has a first conical portion placed radial inside the throat portion and a second conical portion placed radial inside the outlet of the nozzle, the first and second conical portions being formed in different shapes.