Screw compressor and chiller unit provided with same

A screw compressor comprising:

• a male rotor and a female rotor whose rotating shafts are parallel to each other and which are rotated in engagement with each other, forming a compression working chamber;
• and
• an oil separator into which refrigerant discharged from the compression working chamber flows and which separates the refrigerant into refrigerant gas and oil,
• wherein the oil separator includes:
• an outer cylinder;
• an inner cylinder located inside the outer cylinder;
• and an introducing flow path letting refrigerant discharged from the compression working chamber flow in so that the refrigerant swirls to a circumferential direction on an inner wall surface of the outer cylinder,
• wherein an upper end of the inner cylinder is held by the oil separator and an outer wall of the inner cylinder is thereby held independently of the inner wall of the outer cylinder,
• wherein the outer cylinder includes a guide, the guide comprises a side wall configured to gradually reduce a swirling radius of the refrigerant swirling in the guide;
• and an upper wall and a lower wall for suppressing the refrigerant swirling in the guide from spreading in a perpendicular direction,
• wherein the refrigerant flowing into the guide through the introducing flow path swirls while suppressed from spreading in the perpendicular direction in the guide and then is discharged from the guide so as to swirl and go down along the inner wall surface of the outer cylinder, thereby, separated into the refrigerant gas and the oil, and
• wherein the separated refrigerant gas flows into the inner cylinder from a lower end of the inner cylinder and goes up while the separated oil flows down along the inner wall surface of the outer cylinder.