Abstract: 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.

Abstract: 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.

Abstract: A liquid injection type screw compressor in which, in a compression stroke of an working space formed by male and female rotors, liquids such as oil or water is prevented from leaking from the high pressure working space to a gas inlet side, suction resistance of gas sucked from the gas inlet to a rotor casing is reduced to improve volumetric efficiency, and shape forming of the casing is simplified. The liquid injection screw compressor has the male and female rotor pair of screw rotors, the rotor casing (1a, 1b) having a bore for receiving the rotors, a gas suction opening and a gas outlet that are provided in both end sections of the casing and communicate with the bore, and a lip section (4) projected from a bore surface (2) positioned more on the upstream side than a suction seal line (5) of the casing in order to prevent a back flow of the liquid from the bore surface toward the gas inlet side.

Abstract: An oil refrigeration screw compressor being applied to a refrigeration system etc., in which the problem of strength reduction of a bearing material under high temperatures and that of lifetime reduction of the bearing material due to viscosity lowering of lubricant are solved. A lubricant supply system to a compressor body is divided into a bearing oil supply system for supplying lubricant to each bearing of the compressor body at low pressure and into a temperature control oil supply system for supplying lubricant into the compressor body at high pressure. The bearing oil supply system is a closed circuit oil supply system comprising an oil supply tank, an oil cooler, and an oil supply pump, and the temperature control oil supply system is a closed circuit oil supply system comprising an oil separator and an oil cooler.

Abstract: An oil refrigeration screw compressor being applied to a refrigeration system etc., in which the problem of strength reduction of a bearing material under high temperatures and that of lifetime reduction of the bearing material due to viscosity lowering of lubricant are solved. A lubricant supply system to a compressor body is divided into a bearing oil supply system for supplying lubricant to each bearing of the compressor body at low pressure and into a temperature control oil supply system for supplying lubricant into the compressor body at high pressure. The bearing oil supply system is a closed circuit oil supply system comprising an oil supply tank, an oil cooler, and an oil supply pump, and the temperature control oil supply system is a closed circuit oil supply system comprising an oil separator and an oil cooler.