Patent ID: 7823400

Claim:
A two-stage decompression ejector comprising: a variable throttle mechanism including a first throttle passage configured to decompress and expand a fluid and a valve body configured to change a throttle passage area of the first throttle passage; a nozzle having therein a second throttle passage, the second throttle passage being adapted to further decompress and expand the fluid decompressed by the variable throttle mechanism; and a suction portion configured to draw a fluid by a suction effect of a jet-flow fluid ejected at a high velocity from the nozzle, wherein the following formula is satisfied: 0.07 ≦Vo×S/vn≦ 0.7 where Vo is an intermediate-pressure space volume (mm 3 ) that is a volume from an outlet of the variable throttle mechanism to an inlet of the second throttle passage, S is a throttle passage area (mm 2 ) that is a passage sectional area of a minimum passage sectional area portion of the second throttle passage, and vn is a flow velocity (mm/s) of the fluid passing through the minimum passage sectional area portion.