Hitachi, Ltd.

Motohiro Shiga

Kazuo Sato

Masakazu Takasumi

Fumio Fujisawa

Motoji Ohmori

Hiroaki Hata

Kouki Shiohata

Koki Shiohata

Yukio Serizawa

Koichi Sekiguchi

Osami Matsushita

Tsuguaki Koga

Kazuo Ikeda

Yuukichi Nakada

Shin Ishihara

Masatsune Sutou

A rotary compressor has an electric motor and a compressing mechanism drivingly connected together by a crank shaft and disposed in a closed housing. The compressing mechanism has a rolling piston rotatable in a cylinder bore and driven by an eccentric portion of the crank shaft. First, second and third balancers are mounted on an end of the crank shaft and on the opposite ends of a motor rotor, respectively. The second and third balancers are formed therein with weight-adjusting holes by which the masses of the second and third balancers are finely adjusted to fall within tolerable ranges.

Rotary compressor with shaft balancers

A hermetic rotary compressor has a motor unit composed of a stator and a rotor which are arranged in an upper portion of a hermetic housing, an oil-lubricated compressor unit arranged in a lower portion of the hermetic housing, a crank shaft which interconnects said motor unit and said compressor unit, a discharging silencer which is formed by a lower bearing of the compressor unit positioned around the lower end of the crank shaft and a cover of the lower bearing. The hermetic rotary compressor further has a lower balancing weight mounted around a lower shaft end portion of the crank shaft which extends to a position below the discharging silencer and a weight cup surrounding the lower balancing weight. In this hermetic rotary compressor, the lower balancing weight is not disposed within the discharging silencer. Hence, even is the gas-liquid mixture of refrigerant is discharged from the discharging valve into the silencer chamber in the start-up or during liquid-back operation of the compressor, there is no risk that the lower balancing weight undesirably stirs such a fluid.

Hermetic rotary compressor with balancing weights

A vibration diagnosis method and apparatus for rotary machines adapted for measuring the vibration of rotor shaft of a rotary machine, extracting the vibration component synchronous with the revolution of the rotor shaft from the measured vibration data, comparing the amplitude of the extracted vibration component with the amplitude of the overall vibration, analyzing the causes of the synchronous vibration component when the result of the comparison meets a predetermined reference, judging, in accordance with the result of the analysis, whether the vibration due to mass unbalance is attributable to an abrupt generation of mass unbalance or to a thermal bow of the rotor shaft, and displaying the result of the judgment. The analysis of the vibration component is made in real time or making use of data stored in the past.

Vibration diagnosis method and apparatus for rotary machines

A vibration diagnosis method for a rotary machine is disclosed. The presence or absence of a self-excited vibration is determined by checking if a rotating speed is in a rotating speed range which allows the occurrence of the self-excited vibration, if an amplitude of a frequency component corresponding to a first order critical speed is larger than a predetermined level, and if phases at characteristic points of vibration signals change among cycles.

Vibration diagnosis method for rotary machine

A method and apparatus for diagnosing a vibration in a rotor of the rotary machine including detecting the number of rotations and the vibration in the rotor when the rotor is rotating, extracting a vibration component synchronized with the number of rotations, determining whether the vibration component is normal or abnormal, calculating an abnormal vibration component through a vector operation by using the detected vibration component and a previously determined rotor vibration component in a normal state of the rotor, when the detected vibration component is judged to be abnormal, normalizing a vibration pattern of the abnormal vibration component, and determining an unbalance originating position in the rotor, which generates the abnormal vibration, by using a comparison of the normalized abnormal vibration pattern with a normalized vibration pattern of a previously determined unbalanced vibration.

Vibration diagnosing method and apparatus for a rotary machine

A balancing method for use in a multiple-span rotor shaft system for a prime mover, such as a large-capacity, large-sized steam turbine and generator. A balancing influence coefficient representing the relationship between a unit weight and the resultant vibration, when the aforesaid unit weight is attached to a given balance-correcting plane of a multiple span rotor, is first determined, and then a balance-correcting plane, to which is to be attached a balancing weight, is selected, then a balancing weight is determined so as to minimize the value of the residual vibration amplitude, by using the method of least squares, which values are dependent on the value of the vibration amplitude, influence coefficients and balancing weights. Thus, a weight corresponding to the aforesaid balancing weight is attached to the aforesaid balance-correcting plane to reduce vibrations in a shaft.

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Hitachi, Japan

Motohiro Shiga