Hitachi Industrial Equipment Systems Co., Ltd.

Yuta Kajie

Kenji Morita

Shigeyuki Yorikane

Kotaro Chiba

Shuhei Nagata

Masahiko Takano

Takeshi Tsuchiya

An oil-feed-type air compressor includes a compressor main body driven by an electric motor, a separator that separates the oil from compressed air delivered from the compressor main body, an oil supply system that supplies the oil separated by the separator to working chambers of the compressor main body, an oil cooler that is disposed in the oil supply system and cools the oil by using cooling air generated by a cooling fan, and a controller. The controller stops the electric motor and the cooling fan when the continuation time of no-load operation has reached a predetermined value. Further, the controller predicts the return timing at which the electric motor is restarted, on the basis of a sensing history of the delivery-side pressure sensor, and predicts the delivery-side temperature of the compressor main body at the return timing.

Liquid-feed-type gas compressor

A gas compressor inhibits a supply delay of a compressed gas at a time of a return from no-load operation to load operation, and also reduces the consumed motive power. A controller switches between load operation and no-load operation by controlling a suction throttle valve according to a sensed delivery-side pressure, and also controls a rotation speed of an electric motor that drives the compressor. The controller is configured to compute a capacity C of an air supply system that supplies a compressed air generated by the air compressor to a use location of the compressed gas on a basis of load operation duration t1 and no-load operation duration t2, and set a target rotation speed of the electric motor at a time of no-load operation on a basis of the capacity C of the air supply system.

Gas compressor

A screw compressor has first and second screw rotors that suck, compress, and deliver a working medium; a first bearing supporting one end of the first screw rotor coupled to a rotating shaft of a power source; a casing housing the first screw rotor and first bearing; a shaft-sealing member located on an opposite side of a tooth profiler for the first screw rotor relative to the first bearing and seals a through hole in the casing, through which a shaft of the first screw rotor coupled to the output shaft of the power source is inserted; a partition wall isolating the first bearing from the shaft-sealing member; and a liquid-supply route that is provided in the casing and has a first liquid supply opening for supplying a lubricating liquid to the shaft-sealing member and a second liquid supply opening for supplying the lubricating liquid to the first bearing.

Screw compressor

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.

Screw compressor having working chamber closing member to regulate suction working medium flow to a working chamber

A casing of a screw compressor has a delivery inner wall face facing delivery end faces of a male rotor and a female rotor. The delivery inner wall face of the casing has a shield area that shields at least a part of a track of an axial fluid communication path, which is a clearance that periodically occurs at the delivery end faces according to variation of intermeshing of the male and female rotors upon rotation thereof and is bounded by trailing flanks of the male and female rotors. The shield area of the casing is provided with a groove group made up of a plurality of grooves having longitudinal directions. The grooves of the groove group are juxtaposed in the circumferential direction of at least one rotor of the male and female rotors and are arranged such that their sides extending in the longitudinal directions are disposed adjacent to each other. Each groove of the groove group is configured such that its longitudinal direction oriented from the inner circumferential side of the one rotor toward the outer circumferential side is inclined with respect to the radial direction of the one rotor in the same direction as the rotational direction of the one rotor.

An oil feed type air compressor includes a compressor main body, a separator that separates the oil from the compressed air delivered from the compressor main body, and an oil feed system that supplies the oil to the working chambers and bearings of the compressor main body. The oil feed system includes an oil cooler that includes a cooling unit and a cooling unit connected on a downstream side of the cooling unit, an oil feed pipe that is connected to an outlet between the cooling unit and the cooling unit and that supplies the oil cooled by the cooling unit to the bearings of the compressor main body, and an oil feed pipe that is connected to an outlet on a downstream side of the cooling unit and that supplies the oil cooled by the cooling units to the working chambers of the compressor main body.

Liquid feed type gas compressor having a liquid supply system with first and second cooling units

Provided is an oil feed type air compressor which can increase the determination accuracy regarding a deterioration state of oil. An oil feed type air compressorincludes a compressor main body, a separatorthat separates oil from compressed air discharged from the compressor main body, and an oil feeding systemthat feeds the oil separated by the separatorinto a compression chamber of the compressor main body. The oil feeding systemincludes a temperature control valvethat adjusts a diversion ratio for an oil coolerand a diversion ratio for a bypass pipeaccording to a temperature of the oil. The oil feed type air compressorincludes pressure sensorsA andB located in the oil feeding system, a discharge temperature sensorlocated on the discharge side of the compressor main body, and a controllerthat computes, when it is estimated that the diversion ratio for the oil cooleris 100% from the temperature sensed by the discharge temperature sensorexceeding a predetermined value Td, a difference ΔP between the pressure sensed by the pressure sensorA and the pressure sensed by the pressure sensorB and determines a deterioration state of the oil in reference to the difference ΔP.

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Tokyo, Japan

Yuta Kajie