Abstract: A screw compressor includes a screw rotor, an electric motor for driving the screw rotor, bearings supporting the screw rotor and casings housing these members. The screw compressor also includes an oil feeding passage formed in the casing for feeding oil on a high pressure side to the bearings by a differential pressure between the high pressure side and a low pressure side and an oil feeding amount adjusting unit placed in a middle of the oil feeding passage, the oil feeding amount adjusting unit includes a cylinder, a valve element provided to reciprocate inside the cylinder, and plural flow paths provided in the valve element having different flow path areas, the plural flow paths are switched to adjust an oil feeding amount to be fed to the bearings by moving the valve element in accordance with the differential pressure between the high pressure side and the low pressure side.

Abstract: A slide valve forming a part of a bore and movable in an axial direction of the rotors, foot sections on a discharge side end face of the slide valve, and discharge ports and on a discharge chamber side of the slide valve in order to discharge compressed gas taken into a compression operation chamber from the suction chamber and compressed. At a discharge side end portion of the slide valve, first discharge channels and lead the compressed gas discharged from the discharge port and lead the compressed gas to the discharge chamber and second discharge channels are provided on a radial direction outer side of the first discharge channel and opened to the first discharge channels and the discharge chamber to lead a part of the compressed gas flowing in the first discharge channels and feed the part of the compressed gas to the discharge chamber.

Abstract: A screw compressor includes a screw rotor, an electric motor for driving the screw rotor, bearings supporting the screw rotor and casings housing these members. The screw compressor also includes an oil feeding passage formed in the casing for feeding oil on a high pressure side to the bearings by a differential pressure between the high pressure side and a low pressure side and an oil feeding amount adjusting unit placed in a middle of the oil feeding passage, the oil feeding amount adjusting unit includes a cylinder, a valve element provided to reciprocate inside the cylinder, and plural flow paths provided in the valve element having different flow path areas, the plural flow paths are switched to adjust an oil feeding amount to be fed to the bearings by moving the valve element in accordance with the differential pressure between the high pressure side and the low pressure side.

Abstract: A screw compressor and a chiller unit are provided. An oil separator of the screw compressor may include an outer cylinder, an inner cylinder positioned inside the outer cylinder, and an introducing flow path. The upper end of the inner cylinder is held by the oil separator and the outer wall of the inner cylinder is held independently of the inner wall of the outer cylinder. The diameter of the inner wall of the outer cylinder may gradually be reduced along the swirl flow path. The refrigerant via the introducing passage swirls and goes down along the swirl flow path and is separated into gas refrigerant and oil. The separated gas refrigerant flows from the lower end of the inner cylinder into the inner cylinder and goes up, and the separated oil flows down along the inner wall surface of the outer cylinder.

Abstract: A screw compressor is disclosed, which includes a male rotor and a female rotor and an oil separator. The oil separator includes an outer cylinder, an inner cylinder located inside the outer cylinder, and an introducing flow path. An upper end portion of the inner cylinder is held by the oil separator and an outer wall of the inner cylinder is held independently of the inner wall of the outer cylinder. A diameter of an inner wall of the outer cylinder is configured so that the diameter is gradually reduced along a swirl flow path. Moreover, refrigerant that flowed in swirls and goes down along the swirl flow path. The separated gas refrigerant flows from a lower end portion of the inner cylinder into the inner cylinder and goes up and the separated oil flowing down along the inner wall surface of the outer cylinder.

Abstract: A screw compressor in which it is possible to achieve size reduction and reduce the oil rate and a chiller unit equipped with the screw compressor are provided. In the screw compressor, an oil separator includes: an outer cylinder; an inner cylinder positioned inside the outer cylinder; and an introducing flow path that lets refrigerant discharged from a compression working chamber flow in so that the refrigerant swirls to the circumferential direction on the inner wall surface of the outer cylinder. The upper end portion of the inner cylinder is held by the oil separator and the outer wall of the inner cylinder is thereby held independently of the inner wall of the outer cylinder. The diameter of the inner wall of the outer cylinder is so configured that the diameter is gradually reduced along the swirl flow path in which refrigerant that flowed in through the introducing flow path swirls.

Abstract: A slide valve forming a part of a bore and movable in an axial direction of the rotors, foot sections on a discharge side end face of the slide valve, and discharge ports and on a discharge chamber side of the slide valve in order to discharge compressed gas taken into a compression operation chamber from the suction chamber and compressed. At a discharge side end portion of the slide valve, first discharge channels and lead the compressed gas discharged from the discharge port and lead the compressed gas to the discharge chamber and second discharge channels are provided on a radial direction outer side of the first discharge channel and opened to the first discharge channels and the discharge chamber to lead a part of the compressed gas flowing in the first discharge channels and feed the part of the compressed gas to the discharge chamber.

Abstract: A screw compressor includes a valve hole formed at a discharge side end surface of a discharge casing and at a position opening to a compression work chamber; a bypass flow path having the valve hole and a discharge chamber communicate with each other; and a valve body arranged in the valve hole. The screw compressor also includes cylinder chambers provided on a rear surface side of the valve body; a piston reciprocally moving in the cylinder chambers; a rod connecting the piston and the valve body; communication paths for introducing a fluid on a discharge side into the cylinder chamber on a side opposite to a valve body side of the piston and on the valve body side; a pressure discharge path; a plurality of valve means; and a controller controlling the plurality of valves means.

Abstract: A screw compressor in which it is possible to achieve size reduction and reduce the oil rate and a chiller unit equipped with the screw compressor are provided. In the screw compressor, an oil separator includes: an outer cylinder; an inner cylinder positioned inside the outer cylinder; and an introducing flow path that lets refrigerant discharged from a compression working chamber flow in so that the refrigerant swirls to the circumferential direction on the inner wall surface of the outer cylinder. The upper end portion of the inner cylinder is held, by the oil separator and the outer wall of the inner cylinder is thereby held independently of the inner wall of the outer cylinder. The diameter of the inner wall of the outer cylinder is so configured that the diameter is gradually reduced along the swirl flow oath in which refrigerant that flowed in through the introducing flow path swirls.

Abstract: A screw compressor includes a valve hole formed at a discharge side end surface of a discharge casing and at a position opening to a compression work chamber; a bypass flow path having the valve hole and a discharge chamber communicate with each other; and a valve body arranged in the valve hole. The screw compressor also includes cylinder chambers provided on a rear surface side of the valve body; a piston reciprocally moving in the cylinder chambers; a rod connecting the piston and the valve body; communication paths for introducing a fluid on a discharge side into the cylinder chamber on a side opposite to a valve body side of the piston and on the valve body side; a pressure discharge path; a plurality of valve means; and a controller controlling the plurality of valves means.

Abstract: In order to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability, the screw compressor comprises a screw rotor, a low-pressure-side bearing and a high-pressure-side bearing which support the screw rotor, a motor which drives the screw rotor, a motor casing which accommodates the motor, a main casing which accommodates the screw rotor and the low-pressure-side bearing, and a discharge casing which accommodates the high-pressure-side bearing. The motor casing, the main casing, and the discharge casing are accommodated in a steel pipe chamber, and the steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in the axial direction. By using a flange provided on an inner surface of the steel pipe chamber, a flange provided in the main casing, and a sealing component provided between the flanges, the steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space.

Abstract: A screw compressor is for use of a screw chiller, and comprises a pair of screw rotors and a casing housing the screw rotors, a capacity control valve for varying a ratio of volume, a motor for driving the screw rotors and an inverter for varying the rotational speed of the motor. The screw compressor is controlled using rotational speed control means by the inverter and mechanical capacity control means by the capacity control valve independently or combined together according to loads. The maximum efficient point in a capacity control performed solely by the inverter is set to a rotational speed side lower than the rated operation point. In a region where the rotational speed is higher than the maximum efficient point, the inverter solely takes control from a rated rotational speed to a high rotational speed side.