Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi, Ltd.

Toshiaki Yabe

Kohei Sakai

Yuuji Itou

Takeshi Tsuchiya

Kazuaki Shiinoki

Kotaro Chiba

Tomoo Suzuki

Shigeyuki Yorikane

Natsuki Kawabata

Shota Tanimoto

Masakazu Aoki

Takashi Nakajima

Shigeru Machida

Kazuyoshi Iida

Hirotaka Kameya

Takehiro Matsuzaka

Masakatsu Okaya

Yuki Taniyama

Kazumasa Kanai

Yuki Ishizuka

Sho Nikaido

Tomohiro Komatsu

Shotaro Sano

Hirokatsu Kohsokabe

Koji Ikeda

The gas compressor comprising a pre-filter for compressed air is placed at the compressed air intake of the enclosure for primary removal of dust, and an intake filter for further secondary removal of dust, at least one compressor body that draws in and compresses air a motor that drives the compressor body, air cooler cools compressed air, a cooling fan that passes cooling air to the air cooler, a cooling air intake that draws in more than the outside air by means of a cooling fan, a pre-filter for cooling air installed in the cooling air intake, and a controller for controlling an operation of the gas compressor, wherein the controller determines the frequency of cleaning or replacement of the pre-filter for compressed air and the pre-filter for cooling air based on the load factor, which is an indicator of the operating condition.

Gas compressor

A suction flow path of a screw compressor includes a male-side flow path that opens in an axial direction with respect to working chambers in a suction process on the male rotor side and extends from a starting end positioned on one side of a virtual plane to a first termination end positioned on the other side; and a female-side flow path on the female rotor side that extends from the starting end to a second termination end positioned on the other side of the virtual plane. The male-side or the female-side first flow path wall is configured such that at least a partial area in a range from the starting end to the first or the second termination end is closer to a male-side or female-side rotor lobe section from the starting end side toward the first or second termination end side.

Screw compressor with improved suction flow

Provided is an air compressor that suppresses a rise in delivery temperature due to a change in atmospheric pressure, and consequently improves the life of parts. The air compressorincludes a motor, a compressor main bodydriven by the motorto compress air, a delivery pressure sensorthat senses a delivery pressure of the compressor main body, an atmospheric pressure sensorthat senses an atmospheric pressure, and a controller. The controllercompares the delivery pressure sensed by the delivery pressure sensorwith a set pressure, and performs operation control based on a result of the comparison. The controllercorrects the set pressure such that a ratio between the atmospheric pressure sensed by the atmospheric pressure sensorand the set pressure becomes a set value set in advance.

Air compressor

A male rotor of a screw compressor has a cooling flow path extending in an axial direction inside a discharge-side shaft section. A groove structure is provided at at least a part of a region on a wall surface of the cooling flow path between the position of a discharge-side end face of the male rotor and a mounting position of a discharge-side bearing. The groove structure includes grooves or a groove that has a lengthwise component in a circumferential direction of the screw rotor and that are spaced apart in the axial direction. A nozzle which is a stationary member is arranged inside the cooling flow path with a gap between the nozzle and the wall surface of the cooling flow path. The nozzle is arranged in such a manner as to overlap at least a part of the groove structure in the axial direction.

Screw compressor

Compressor

A multi-stage screw compressor includes a plurality of stages of compressor bodies that compress a gas in sequence. Each of the 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 of 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.

Multi-stage screw compressor

In a screw compressor, a lobe of a lobe profile of a female rotor includes: a first contour line defining a leading flank; a second contour line defining a trailing flank; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile, when a first angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, a second angle formed by two line segments linking the second rotation center and both ends of the second contour line, and a third angle formed by two line segments linking the second rotation center and both ends of the third contour line, the third angle is greater on the delivery side in the axial direction, and the first angle is smaller on the delivery side in the axial direction.

Screw compressor and screw rotor

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip. In at least the radial cross section of the screw portion, different members are continuously joined as an integral structure in a cross section of at least one of the axial center portion and the support portion and the outer surface portion.

Screw rotor and screw-type fluid machine main body

An oil free compressor includes a cooling fan, a low-pressure stage air-cooled heat exchanger, a high-pressure stage air-cooled heat exchanger, and a lubricating oil air-cooled heat exchanger. The cooling fan is provided independently from each of the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the lubricating oil air-cooled heat exchanger.

Oil free compressor system

An oil-free scroll compressor prevents wraps from being broken and provides improved reliability. The oil-free scroll compressor includes an orbiting scroll member and fixed scroll members, and has compression channels into which water is injected each formed between the intake port and exhaust port provided in the fixed scroll member. The oil-free scroll compressor includes temperature sensors each of which detects temperature in the compression channel, regulating valves each of which controls ratio of the amount of the water to be injected into the respective compression channels to the total amount of the water to be injected into the compression channels, and controller which controls the opening degrees of the regulating valves such that a difference between the detected temperatures from the compression channels is small.

Oil-free scroll compressor

A conventional machine package faces problems concerned with costs, weight, etc. and also a problem of antinomy that an attempt to enhance the noise reducing performance increases the airflow resistance and then deteriorates the cooling performance. Providing a sound absorbing structure with the heat radiation performance ensured within a practical range and then with considerably improved noise reducing effect achieves a low-noise machine package with a downsized casing and a reduced cooling fan power. There is provided a sound absorbing structure having a plurality of polyester fiber sound absorbing cylinders each formed into a circular-cylindrical shape, formed of a base material of polyester fiber whose surface is combined and covered with polymer nonwoven fabric of polyester fiber or the like, and arranged at a support member in at least either of a suction port and an exhaust port in such a manner that long axes of the sound absorbing cylinders intersect substantially perpendicularly with a flow direction of air flowing through the suction port or the exhaust port. This makes it possible to reduce noise while controlling the airflow resistance minimum, thus achieving downsizing of a cooling fan and reduction of a cooling fan power.

Low-noise machine package

In a double toothed type scroll compressor, spiral wraps are formed on both sides of an end plate of an orbiting scroll, and wraps adapted to engage with the spiral wraps are formed on a stationary scroll. A dust wrap is formed on a side diametrically outside of the wrap of the stationary scroll. Grooves are formed on ends of the respective wraps to receive therein seal members formed of a high polymer material. Electric charge of static electricity produced when the seal members slide on surfaces of the mating end plate is made to flow from a bolt provided on an end of a crankshaft to the stationary scroll through a brush, thereby preventing accumulation of electric charge in a crankshaft.

Growing community of inventors

Shizuoka, Japan

Toshiaki Yabe