Hitachi, Ltd.

Hitachi Plant Technologies, Ltd.

Minoru Taniyama

Haruo Miura

Masahiro Mase

Takashi Nagaoka

Kazuki Takahashi

Seiji Tsuru

Tomohiro Naruse

Toshio Hattori

Kazuaki Nakamori

Yoshitsugu Tsutsumi

Makoto Terajima

A heat exchanger used in a screw air compressor has a low temperature chamber through which low temperature fluid flows and a high temperature chamber through which high temperature fluid flows. The low temperature chamber and the high temperature chamber are separated by a partition plate. The high temperature chambers and the low temperature chambers are alternately arranged in layers, so that the low temperature chambers are disposed at both ends in a layered direction. Additionally, the flowing direction of the low temperature fluid in the low temperature chambers and the flowing direction of the high temperature fluid in the high temperature chambers are substantially orthogonal to each other.

Heat exchanger for air compressor

A package-type screw compressor includes a low-pressure stage state compressor and a high-pressure stage compressor. Motive power is transmitted from an electric motor to the two compressors via a speed increaser. The discharge gas, compressed and heated to a high temperature by the low-pressure stage compressor, is cooled by an intercooler. The discharge gas, compressed and heated to a high temperature by the high-pressure stage compressor, is cooled by an aftercooler. A casing of the intercooler and that of the aftercooler are formed integrally with a speed increaser casing, reducing the number of component parts. A cooler portion, formed by the intercooler and the aftercooler, is spaced from the speed increaser casing, thereby preventing heat, produced by the compressed air, from being transmitted to the speed increaser casing.

Screw compressor

A vacuum pump of the present invention comprises a housing including a suction port and an exhaust port, a stator fixed in the housing, a rotor rotatably supported in the housing, and a cooling jacket provided adjacent to the stator. Gas suctioned from the suction port and having a pressure substantially equal to or close to the atmospheric pressure is exhausted from the exhaust port. A cooling fluid having a thermal conductivity less than that of water, for example, of 0.08 to 0.25 Kcal/m.h..degree.C. flows through the cooling jacket. When the gas contains aluminum chloride, the cooling fluid flows into the cooling jacket in such a manner that the temperature inside a gas conduit is maintained to be higher than the sublimation temperature of aluminum chloride. Lubrication oil may be supplied as the cooling fluid to the cooling jacket from the same supply line as lubrication oil supplied to oil lubricating bearings provided below a pump mechanism unit. A closed-loop line may be comprised of the cooling jacket, a tank, the supply line, and a return line, to thereby circulate the cooling fluid by a pump.

Vacuum pump

A vacuum pump with a seal structure for a pump unit of the vacuum pump and a driving mechanism for rotating a rotor in the pump stages of the pump is disclosed. The seal structure is provided with a narrow gap sealing arrangement formed by a stationary member which is opposed to the portion of a shaft of the driving mechanism which is between the pump unit and an upper bearing supporting the same shaft, which narrow gap sealing arrangement comprises first, second and third seal portions; a mechanism for supplying a discharge gas to the first seal portion; and a mechanism for supplying a purge gas to the second and third seal portions. Owing to these parts, the feed rate of the purge gas can be minimized, and the entry of the oil mist, which occurs during the lubrication of the bearing, into the interior of the pump unit can be prevented. This enables the interior of the pump unit to be kept clean.

Vacuum pump with plural labyrinth seal portions

A vacuum pump including a centrifugal compressor stage on the side of a suction opening and a circumferential flow compressor on the side of an exhaust opening. The centrifugal compressor pump works as a Siegbahn pump at a steady state, and works as a centrifugal compressor under a transient condition at the initial stage of the pump operation, thus obtaining a high pumping speed under the transient condition.

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Ami, Japan

Minoru Taniyama