Hitachi Zosen Corporation

Kazuyuki Miyake

Kazunori Koba

Kazuo Yoshida

Takeshi Dohku

The invention provides a cleaning method comprising: a step of immersing the object of cleaning first in a first tank to wash roughly by bubbling from beneath, and showering with purified water from above when lifting the object, a step of immersing the object coming from the first tank in a second tank to wash preliminarily with ultrasonic waves, and showering with purified water from above when lifting the object, a step of immersing the object coming from the first tank or second tank successively in a third tank to wash thoroughly with ultrasonic waves and water jet, and showering with purified water from above when lifting the object, and a step of immersing the object coming from the third tank finally into a fourth tank to finish with water jet, and lifting. In this cleaning method, only purified water harmless to human and environment is used as cleaning fluid, and the same cleanliness as in conventional cleaning with chlorofluorocarbons or trichloroethane is obtained, while there is no side effect such as discoloring of work surface.

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Ibaraki, Japan

Kazuyuki Miyake