Other

Hitachi, Ltd.

Tomoyoshi Okamura

Junichi Kurokawa

Kouichi Irie

Akira Manabe

Sumio Sudo

Hitoharu Kimura

Taiji Hashimoto

Takahide Nagahara

Norimitsu Kuwabara

Yoshio Anzai

In an axial flow hydraulic machine, a plural number of grooves are formed on an inner surface of a casing, directed into a pressure gradient direction, for connecting between an inlet side of an impeller and an inside of blade residing region on the casing inner surface. With movement of movable members provided on the casing inner surface, the grooves appear within the blade residing region in an unstable operation region, while the grooves cause no interference with the blades of the impeller in a stable operation region.

Axial-flow type hydraulic machine

For improving characteristic uprising at the right-hand side of head-flow rate characteristic of a turbo machine, as well as for suppressing increase of vibration and/or noises thereof, a plurality of first grooves in direction of gradient in pressure of fluid are formed on an inner flow surface of a casing, for connecting an inlet side of blades of an impeller and an area on the inner flow surface of the casing where the impeller blades reside in, over an inner circumference of the casing. Also, second grooves in a circumferential direction are formed in an area on the inner flow surface of the casing where the impeller blades reside in, for communicating the first grooves in the circumferential direction of the casing.

Turbo machines

A turbo-type machine, comprising a casing storing an impeller within an inside thereof, and a plural number of grooves formed on an inner surface of the casing in a direction of pressure gradient of fluid, wherein the grooves are provided from 80 to 150 pieces around a periphery on the inner surface of the casing, and a total width of the grooves all around the inner surface of the casing is from 30% to 50% of a peripheral length on the inner surface of the casing. Also, the area on cross-section of the groove within an area where the blades exist is made larger than that of the groove outside where the blades exist, or openings are drilled on a bottom surface of the grooves, each penetrating through thickness of the casing, or the groove is made in a two-layer structure in the direction of pressure gradient of fluid. Or, a round portion is formed at a tip of the blade , or a fin , thereby suppressing the cavitations to generate, as well as obtaining stabilization of the characteristic curve thereof.

Turbo-type machines

A pump, comprising: an impeller having blades; and a casing for storing the impeller therein, on an inner surface of which, confronting to the impeller, are formed plural numbers of shallow grooves in a direction of pressure gradient of fluid, around a periphery thereof, wherein the fluid being increased up in pressure by the blades flows within the grooves in a reverse direction, directing to an upstream side, so as to spout out at a place where re-circulations occur when the flow rate is low in amount. Also, an outlet angle of the blade is set to be within a region from 30 degree to 90 degree. Further, preferably, front guide vanes are provided, so that a direction of absolute flow at an outlet of the impeller is directed into an axial direction of the pump at an amount of designed flow rate.

Pump

For improving characteristic uprising at the right-hand side of head-flow rate characteristic of a turbo machine, as well as for suppressing increase of vibration and/or noises thereof, a plurality of first grooves,in direction of gradient in pressure of fluid are formed on an inner flow surface of a casing, for connecting an inlet side of blades of an impeller and an area on the inner flow surface of the casing where the impeller blades reside in, over an inner circumference of the casing. Also, second grooves,in a circumferential direction are formed in an area on the inner flow surface of the casing where the impeller blades reside in, for communicating the first grooves in the circumferential direction of the casing.

Growing community of inventors

Minori, Japan

Tomoyoshi Okamura