A refrigeration cycle device according to the present invention includes a compressor having a first compression chamber and a second compression chamber, a condenser, a decompressor, an evaporator, an injection path configured to introduce intermediate pressure refrigerant, a communication passage configured to introduce intermediate pressure refrigerant compressed in the first compression chamber to the second compression chamber, and a switch element configured to selectively make the second compression chamber communicate with the evaporator or make the second compression chamber communicate with the communication passage. The injection path introduces the intermediate pressure refrigerant to the second compression chamber. Single-stage compressing operation is performed when the second compression chamber is communicated with the evaporator, and two-stage compressing operation is performed when the second compression chamber is communicated with the communication passage.

A method for controlling a compressor device (1) with a compressor element (2) and oil circuit (14) with oil (15) that is injected into the compressor element (2) by a fan (19) via a cooler (18), with a bypass pipe (20) across the cooler (18), whereby when the temperature (T) of the compressor element (2) is less than a value (T.sub.set), the method including the following steps: switching the fan (19) off; when the temperature (T) is still less than T.sub.set, driving the oil (15) via the bypass pipe (20); when the temperature (T) is still less than T.sub.set, decreasing the quantity of oil (15) that is injected into the compressor element (2) until the temperature (T) is equal to T.sub.set

A refrigeration cycle apparatus includes: a refrigeration cycle circuit in which a compressor, a condenser, a first expansion valve, and an evaporator are connected by refrigerant pipes; an injection pipe having a refrigerant inflow side end and a refrigerant outflow side end, the refrigerant inflow side being connected between the condenser and the first expansion valve, the refrigerant outflow side end being connected to a suction side of the compressor; a second expansion valve provided at the injection pipe; and a controller that controls a rotation speed of the compressor and an opening degree of the second expansion valve. In the case of reducing a heat-exchange capability of the evaporator when the rotation speed of the compressor is a specified rotation speed, the controller performs a low load operation during which refrigeration is caused to flow through the injection pipe.

A compressor includes a housing, in which a compression chamber is provided; an injection pipeline installed in the housing and configured to inject a fluid into the compression chamber; and a solenoid valve installed on the injection pipeline in the housing and configured to allow or block off the injection of the fluid through the injection pipeline.

A gas compressor is disclosed that includes a first rotor having a first rotor body, the first rotor body including a plurality of helical lobes, an infernal volume within the first rotor body defined by a wall, and a turbine disposed within the internal volume, the turbine including a turbine body and a plurality of airfoils extending substantially radially from the turbine body to the wall, where the internal volume is structured to enable a cooling fluid to flow therethrough. The gas compressor further includes a second rotor body including a plurality of helical flutes, an inlet manifold and an outlet manifold, both disposed within the second rotor body, and a body channel within at least one flute extending from and in fluid communication with the inlet manifold to the outlet manifold, where the body channel is structured to enable a cooling fluid to flow therethrough.

A screw compressor according to an embodiment includes a rotor casing, a pair of screw rotors disposed in the rotor casing and engaging with each other, and a movable portion disposed so as to be movable in a rotor shaft direction of the pair of screw rotors. The movable portion includes liquefied liquid supply ports capable of supplying a liquefied liquid of a compressed gas toward tooth groove spaces formed by the pair of screw rotors.

A gas treatment device treats, at atmospheric pressure, the gases pumped by at least one rough pumping device. The gas treatment device includes a treatment chamber and at least one discharge pipe to connect a discharge of the at least one rough pumping device to an inlet of the treatment chamber. The gas treatment device further includes at least one auxiliary pumping device to lower the pressure in the at least one discharge pipe, situated less than 1 meter from the inlet of the treatment chamber, such as less than 50 cm.

A liquid-injected screw compressor includes: a casing that houses a screw rotor and a bearing, and has a suction port and a suction chamber connected to the suction port; a suction throttle valve that is installed at the suction port, and has a housing; and an intake-gas bypass system that establishes communication between a primary side and a secondary side of the suction throttle valve. The intake-gas bypass system includes: an intake-gas bypass flow path that is provided in a wall section of the housing, and has a primary-side opening section opening into the primary side of the suction throttle valve, and a secondary-side opening section opening into the secondary side of the suction throttle valve; and a first check valve arranged in the intake-gas bypass flow path. The intake-gas bypass flow path has an external opening section that opens to an outside of the housing and that allows insertion and withdrawal of the first check valve. Thereby, it is possible to make the system that communicates with the suction chamber in the casing and is provided with the reverse-flow inhibition mechanism a pipeless structure without impairing advantages of external pipes.

The liquid level of a liquid supply type compressor including a gas-liquid separator is dynamically monitored. A liquid supply type gas compressor includes a compressor body of a liquid supply type; a gas-liquid separator that separates a liquid from a compressed gas, which is discharged, to store the liquid; a liquid piping system that supplies the liquid stored to the compressor body; an internal pipe that extends in an internal space of the gas-liquid separator, and includes at least two hole portions, of which disposition positions are different from each other in a height direction, on an internal space side to communicate with the liquid piping system; and a detector that detects a pressure or a temperature of a fluid flowing through the liquid piping system. At least one of a determination as to whether or not the pressure or the temperature detected by the detector is more than a first set value set in advance and a determination as to whether or not the pressure or the temperature detected by the detector is less than a second set value which is set in advance to be less than the first set value is performed to determine which one of the gas and the liquid is the fluid flowing through the liquid piping system.

A vacuum line and method for controlling a vacuum line in which an auxiliary pumping device and a diluent gas injection device are controlled according to a first operating mode in which the pressure prevailing in the discharge pipe is maintained at less than or equal to 20,000 Pa or according to a second operating mode in which the pressure prevailing in the discharge pipe is greater than 20,000 Pa, and the injection of a diluent gas into the stream of the pumped gases is controlled, downstream of an intake of the rough pumping device, such as into the discharge pipe and/or into the rough pumping device and/or into the auxiliary pumping device by the diluent gas injection device in the second operating mode.