Hitachi, Ltd.

Mizuho Tanaka

Hideo Ito

Hisanao Kita

Isao Yanagida

Shoji Sato

Junzo Komatsu

Yukio Yamaguchi

Tadakazu Oguri

Hidetoshi Togashi

Harumasa Sato

Mutsuo Suzuki

Kagehiko Yamamoto

A water intake portion of a hydraulic machine consists of a casing and a speed ring positioned between the casing and guide vanes for guiding water from the casing to the guide vanes. The speed ring consists of a pair of upper and lower flat members of a ring form, a plurality of stay vanes positioned between the aforesaid pair of members for interconnecting same rigidly, and a reinforcing member of a cylindrical form, which is welded to the top surface of the upper flat member between the inner and outer circumferential edges of the upper flat member. Edges defining therebetween an opening of this casing are welded to the top surface of the upper flat member of a ring form, of the speed ring in the position between the aforesaid reinforcing member and the outer circumferential edge of the upper flat member, as well as to the undersurface of the lower flat member of a ring form, respectively. In this respect, the welding of the reinforcing member of a cylindrical form to the top surface of the upper flat member of a ring form is followed by the welding of the edges of the opening of the casing to the upper and lower flat members of a ring form.

Method for construction of water intake portion of hydraulic machine

An object disposed in a fluid flow and defined by two surfaces, each extending along a stream line and one of said two surfaces having a reference contour. To eliminate the danger that a violent oscillation is generated due to resonance between the natural oscillation of the object and the oscillation caused by Karman's vortex which develops at the downstream end portion of the object, said downstream end portion of the object is so formed as to provide a configuration satisfying the following relations:

Object disposed in a fluid flow and having a selected configuration to

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Hitachi, Japan

Mizuho Tanaka