Patent ID: 6904769

Claim:
An ejector-type depressurizer for a vapor compression refrigeration system, wherein the vapor compression refrigeration system includes a compressor that compresses refrigerant, a radiator that cools the refrigerant compressed by the compressor, and an evaporator that vaporizes refrigerant, the ejector-type depressurizer comprising: a stationary nozzle arrangement that converts pressure energy of the refrigerant supplied from the radiator into velocity energy to depressurize and expand the refrigerant; a pressurizer arrangement that mixes the refrigerant discharged from the nozzle arrangement with the refrigerant drawn from the evaporator and converts the velocity energy of the refrigerant discharged from the nozzle arrangement into pressure energy to increase the pressure of the mixed refrigerant discharged from the pressurizer arrangement, wherein the pressurizer arrangement includes a refrigerant passage that conducts the refrigerant supplied from the nozzle arrangement and the refrigerant supplied from the evaporator; and refrigerant passing zone varying means for varying a cross sectional size of a variable refrigerant passing zone of the refrigerant passage, through which the refrigerant from the nozzle arrangement and the refrigerant from the evaporator mainly pass in the pressurizer arrangement during operation of the ejector-type depressurizer, wherein: the refrigerant passing zone varying means includes a needle, which is received in the pressurizer arrangement and is axially movable with respect to the stationary nozzle arrangement; and the needle has a tapered portion at a distal end part of the needle to vary the cross sectional size of the variable refrigerant passing zone of the refrigerant passage of the pressurizer arrangement, wherein the tapered portion is tapered along an entire axial extent of the tapered portion to have a decreasing diameter toward an outlet of the pressurizer arrangement where the refrigerant is discharged from the pressurizer arrangement.