Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi, Ltd.

Hitachi Industries Co., Ltd.

Hitachi, Ltd., Trustee, for the Benefit of Hitachi Air Conditioning Systems Co., Ltd.

Hirotaka Kameya

Masakazu Aoki

Takashi Saito

Kazuaki Shiinoki

Shigekazu Nozawa

Masayuki Urashin

Takeshi Hida

Hideharu Tanaka

Natsuki Kawabata

Atsushi Watanabe

Toshiyuki Ajima

Toshihiro Yamada

Masaru Yamasaki

Tatsuo Natori

Akihiko Yamamoto

Katsumi Matsubara

Norinaga Suzuki

Mitsuru Fujiwara

Masaharu Senoo

Kotaro Naya

Hiroki Ohsumimoto

Tomu Kato

Kazuhiro Matsumoto

Hirokatsu Kohsokabe

Hiroki Osumimoto

Motohiro Satoo

Masahiko Takano

Takeshi Tsuchiya

Hitoshi Nishimura

Fumio Takeda

Yuuichi Yanagase

Toshiaki Yabe

Masato Nakanishi

Eiji Sato

Masayuki Kasahara

Kouji Aizawa

Kazuaki Shinoki

Kohtaro Chiba

Masanori Ishikawa

Seiji Tsuru

In an oil-cooled screw compressor, a tooth crest arc of a fixed width is provided to the tooth crest of a male tooth profile, and simultaneously a tooth bottom arc is provided to the tooth bottom of a female tooth profile. Due to the actions thereof, the operation chamber immediately before disappearing exists only in a bottom half region from a line that connects the centers of the male and female tooth profiles, and the opening area relative to the volume of the operation chamber can be increased. As a result, the discharge of oil becomes smooth and energy loss is reduced.

Oil-cooled screw compressor

A high reliability water injected scroll air compressor is provided with an orbiting scroll, a fixed scroll corresponding to the orbiting scroll, a motor that generates driving force for making the orbiting scroll orbit the fixed scroll, a compressing path from a suction port to a discharge port, and a portion for injecting water into the compressing path. The operation is controlled by a switching operation in which water is injected into the compressing path and then no water is injected. Corrosion, failure of activation, and concerns about wrap contact when water is injected into an air end are avoided by switching the operation with water injection and the operation without water injection so as to prevent water from remaining in the air end.

Water injected scroll air compressor

An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Oil-flooded screw compressor, motor drive system, and motor control

As pressure in a water tank rapidly rises when water inside a compressor is evaporated by the high temperature of compressed air and this situation makes the operation unstable, an object of the present subject matter is to address this problem. A water injected scroll air compressor is provided with: an air end of the scroll air compressor; a driving unit that generates driving force for the air end; a compressing path from a suction port to a discharge port; a portion to inject water into the compressing path; a discharge piping of air discharged from the air end; a tank provided on a path of the discharge piping for storing water separated from the compressed air; and a cooler that is provided on the path of the discharge piping between the tank and the air end and cools the compressed air discharged from the air end.

Disclosed is a water-injection type scroll air compressor whose pre-stopping operation time for drying can be reduced while enhancing compressor efficiency. The compressor bodyincludes a water supply linefor supplying water to a water feederconnected to an air suction line. The water supply lineis provided with a control valvethat can control a flow rate of the water. A controllerconducts driving control of the control valvein a 5&#xd7;10to 40&#xd7;10range of an injected-water volume ratio (more specifically, a volume ratio between an intake air flow rate and injected-water flow rate in the water feederof the suction line) and at the same time, in an injected-water volume ratio range of the compressor characterized so that an increase rate of overall adiabatic efficiency of the compressor per 1&#xd7;10increase rate of the injected-water volume ratio stays less than 2% of an original or initial value.

Water-injection type scroll air compressor

Oil-flooded screw compressor, motor drive system, and motor control device

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

To maintain the functionality as a compact and inexpensive motor-mounted internal gear pump and also offer further inexpensiveness and reliability. The motor-mounted internal gear pumphas a pump partincluding: an inner rotor, an outer rotor, a pump casing and an internal shaft. The pump casing has flat inner surfaces facing both end faces of the inner rotorand the outer rotor. The internal shaftincludes a bearingwhich is inserted into an axial hole of the inner rotorand a fitting partextending from both its ends in both axial directions. The pump casing includes two pump casing membersas separate members with flat inner surfacesrespectively. The fitting partof the internal shaftis fitted in to fitting holesmade in the flat inner surfaces of the two pump casing membersand the two pump casing membersare connected with each other outside the outside diameter of the outer rotor while both end faces of the bearingare in contact with the flat inner surfaces

Motor-mounted internal gear pump and manufacturing method thereof and electronic equipment

A screw compressor rotatably accommodates, within a casing including a suction port and a delivery port, a pair of female and male rotors under the meshed state and compresses gas in the state where a liquid is mixed by pouring the liquid to the gas confined within a working chamber formed with both rotors and the casing. On the wall surface of the casing opposing to the rotor delivery end, a recessed part is provided. The working chamber is communicated with the recessed part immediately before isolating from the delivery port and this communication is maintained until a volume of the working chamber substantially becomes zero. Thereby, the screw compressor can be control increase in power consumption, vibration, and noise.

Screw compressor

A fuel cell stack has an air chamber to which is introduced compressed air that is produced by compressing the atmosphere with a compressor. Energy is recovered from exhaust discharged from the air chamber as it is expanded by an expander. The compressor and the expander are connected to each other via the air chamber of the fuel cell stack through piping. The pressure of the exhaust flowing through the piping is detected by a pressure sensor and, based on the detected pressure, a throttle valve controls a flow rate of the exhaust drawn into the expander.

Fuel cell system

A screw compressor comprises a casing, and a male and a female rotor formed with axially twisted screw grooves and accommodated in the casing, the both rotors being rotated by timing gears fixed to the respective rotors while a desired minute gap is kept therebetween, and a method of manufacturing rotors therefor. In the screw compressor, the male and female rotors formed with axially twisted screw grooves in the casing comprise concave stripes having a minute depth and provided on the respective screw grooves to extend along directions of twist thereof, and leakage of a compressed air is less to give a high compression efficiency.

Screw compressor and method of manufacturing rotors thereof

An oil separator and an oil reservoir are formed integral with a main casing. Also, an opening communicated with the oil reservoir is formed in a part of a lower portion of an oil separation space of the oil separator. Preferably, the opening is formed so that its width is increased as it approaches an outer peripheral side of the oil separation space from a center thereof. Further, a safety valve is installed so that a line connecting between the safety valve and the center of the oil separator is made substantially in parallel to axes of screw rotors.

A screw compressor of which a female rotor is driven by a motor, and of which a male rotor is driven by the female rotor. The male or female rotor is composed of a member which is made of cast iron and is subjected to surface hardening treatment or heat treatment including quenching. The surface hardening treatment may include sulphonitriding or nitiriding treatment. In the case of subjecting the cast iron to the heat treatment, austemper treatment is applied.

Screw compressor and method of manufacturing rotor for the same

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Tsuchiura, Japan

Hirotaka Kameya