A screw compressor is provided having adjustable internal volume ratio, including a body and a male rotor, a female rotor and a slide valve configured inside the body, a groove being configured at one side of the male rotor and the female rotor, and the slide valve being configured inside the groove with the slide valve movable inside the groove from a first position corresponding to a minimum internal volume ratio to a second position corresponding to a maximum internal volume ratio.

The invention relates to a turbine engine, such as a turbojet engine or a turboprop engine of an aeroplane, including at least one oil circuit (8) and cooling means (16) for cooling the oil of said circuit (8), the cooling means (16) including a refrigerant circuit (17) provided with a first heat exchanger (18) capable of exchanging heat between the refrigerant and the air and forming a condenser, a second heat exchanger (19) capable of exchanging heat between the refrigerant and the oil of the oil circuit and forming an evaporator, a pressure reducer (20), a compressor (21) and first regulator means (31) capable of regulating the pressure of the refrigerant entering the first exchanger (18).

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.

The disclosure relates to compressors for heat exchange systems, heat exchange systems having such compressors, and methods for controlling operation of compressors. The compressor includes a drive device for driving the compressor and having at least a first and second working conditions. An output power of the drive device under the second working condition is greater than an output power under the first working condition. The compressor has at least one upload/download flow path configured to be opened before the drive device is switched from the first working condition to the second working condition to reduce a suction flow of the compressor until current operating parameters of the compressor reach preset values, after which the switching is performed, and to increase the suction flow until the compressor is in a required working state, after the switching is completed.

A screw compressor includes: a containment body including: a suction chamber and a suction port for a fluid to be compressed; a delivery chamber and a discharge port for the compressed fluid; a containment seat for two helical compression rotors; two helical compression rotors; an electric motor to actuate the helical compression rotors; lubrication for the helical compression rotors; filtration of the compressed fluid; an inverter connected to the electric motor; an electronic control unit configured to control the inverter; a low-pressure sensor located at the suction port and connected to the electronic control unit; a high-pressure sensor located at the discharge port and connected to the electronic control unit; an adjustment spool configured for adjusting the width of an outlet opening from the compression rotor chamber; a fluid actuator to move the adjustment spool; a current meter that measures the electric current absorbed by the electric motor.