Abstract: A multi-stage screw compressor includes a plurality of stages of compressor bodies that compress a gas in sequence, and each stage of the plurality of stages of compressor bodies has both male and female rotors that are housed revolvably in a casing in a mutually meshing state. The male and female rotors each include a rotor lobe section having a suction-side end face and a discharge-side end face on one end and the other end thereof in the axial direction and having a twisted lobe extending from the suction-side end face to the discharge-side end face. The male and female rotors in a downstream-stage compressor body as at least one certain stage, excluding an upstream-stage compressor body as the first stage, among the plurality of stages of compressor bodies are each configured such that their lead increases from the suction side in the axial direction of the rotor lobe section toward the discharge side.

Abstract: This screw compressor is provided with a screw rotor, a casing accommodating the screw rotor, and a liquid feed mechanism for feeding a liquid into an operating chamber enclosed by the casing, wherein the pitch of the screw rotor changes in the axial direction from a suction end surface toward a discharge end surface.

Abstract: A screw compressor for compressing a working medium sucked through a suction opening and discharging the compressed working medium through a delivery opening, wherein the screw compressor includes: a male rotor and a female rotor that rotate while meshing with each other; a casing that houses the male rotor and the female rotor and is provided with a bore which forms a working chamber designed, together with the male rotor and the female rotor, to compress the working medium; a drive unit that rotationally drives at least one of the male rotor and the female rotor; a working chamber closing unit that forms a suction port for sucking the working medium into the working chamber and closes the working chamber when the working chamber reaches a specified capacity; and a suction space that connects the suction opening and the suction port to allow communication therebetween, wherein an open space that connects the suction opening and the suction port to allow communication therebetween is provided between a shaft

Abstract: One end of a yoke is arranged near one end of an iron core of an electromagnet. The other end of the yoke is coupled to the other end of the iron core. The one end of the yoke has side walls which oppose the side surfaces of the one end of the iron core, and a bottom which opposes the bottom of the iron core. The magnetic pole at the other end of the iron core is guided to the other end of the yoke. A movable member is disposed at the one end of the iron core. The movable member comprises a permanent magnet disposed at the center of a frame, and iron pieces, one end of each of which abuts against the poles of the permanent magnet. The movable member partially surrounds the iron core so that the iron pieces are located between the iron core and the side walls of the yoke. The movable member is moved in the direction perpendicular to the axis of the iron core by the sum of the magnetic fields of the permanent magnet and the electromagnet.