Kabushiki Kaisha Toshiba

Atsuhide Suzuki

Osamu Watanabe

Toshio Suzuki

Kentaro Takagi

Kazuaki Ikeda

Toshihiro Fujiwara

Masataka Fukuda

Hirotsugu Kodama

Yukio Shinozaki

Toshihiro Matsuura

Hisao Fujihashi

Shinya Ayano

Shigeo Hosoi

A geothermal turbine comprises a turbine casing, a turbine rotor shaft, a plurality of nozzle diaphragm outer rings fixed to the turbine casing, a plurality of nozzle diaphragm inner rings located radially inside the nozzle diaphragm outer rings, a plurality of nozzles placed between the nozzle diaphragm outer rings and the nozzle diaphragm inner rings, which form a steam passage, a plurality of rotor blades mounted on the turbine rotor shaft, which face the nozzles and form a blade cascade in a circumferential direction, a shroud arranged on tip of the rotor blade, an overhang attached to the nozzle diaphragm outer ring, which extends downstream of the nozzles and has an inner surface facing radially outside the shroud, and a plurality of sealing fins which protrude radially outward from the shroud and face the overhang.

Geothermal turbine

In an axial-flow turbine, at least one of front and rear side contact surfaces of shrouds (3a or 3b) of blades (1a or 1b) with respect to the turbine rotational direction is formed at certain angle with respect to a radial line connecting the rotor center and the contact surface. The shroud (3a) of the blade (1a) of a first kind is formed in a trapezoidal shape converging radially outward in cross section taken in a plane perpendicular to the turbine axial direction, and the shroud (3b) of the blade (1b) of a second kind is formed in an inverted trapezoidal shape converging radially inward in the cross section. Further, half of an angle (2.alpha.) between the front and rear side contact surfaces of the shrouds (3a or 3b) is made smaller than a static frictional angle of the contact surface. Since the shroud contact surfaces of two adjacent blades can be kept in pressure contact with each other under all operating conditions, a large dynamic stress reduction and superior damping properties can be obtained without producing excessive initial stresses at the blade airfoil and blade dovetail attachment portion.

Rotor blade damping structure for axial-flow turbine

A forced-air cooling apparatus is provided for a steam turbine which comprises an outer casing composed of upper and lower casing halves, an inner casing composed of upper and lower casing halves and disposed inside the outer casing and a rotor coaxially disposed inside the inner casing for forming a steam flow passage between the inner casing and the rotor and in which steam introduced into the steam flow passage from a steam inlet portion is impinged against blades of the rotor to impart a turning force thereto as a movable portion such as rotor with respect to a stationary portion such as an inner casing. The forced-air cooling apparatus comprises a cooling passage including a first cooling air passage formed between the inner casing and the rotor and a second cooling air passage formed between the outer casing and the inner casing, an external air inlet and outlet portion for charging external cooling air into the first and second cooling air passages during the turning operation period and discharging the cooling air after passing the first and second cooling air passages and a control unit for controlling the flow rate of the cooling air passing the first cooling air passage in response to a signal corresponding to a differential expansion detected by a differencial expansion detector between the movable portion and the stationary portion of the turbine and controlling a flow rate of the cooling air passing the second cooling air passage in response to a signal corresponding to a temperature difference between the upper and lower casing halves of the outer casing of the turbine.

Forced-air cooling apparatus of steam turbine

Growing community of inventors

Kanagawa-ken, Japan

Atsuhide Suzuki