Hitachi Plant Technologies, Ltd.

Hitachi, Ltd.

Tetsuya Kuwano

Hiromi Kobayashi

Hideo Nishida

Masanori Tanaka

Manabu Yagi

Takanori Shibata

Takeshi Tsukamoto

Yoshihisa Maeda

Masaaki Iwasa

Haruo Miura

Taiji Hashimoto

Tadaharu Kishibe

Ryujiro Udo

Hideto Nogiwa

Toshio Itou

Hirotsugu Kawanaka

Tomohiro Naruse

Mitsuhiro Narita

Shinji Imaoka

Size reduction of a barrel-type casing using a shear key is aimed for while ensuring a necessary area of a head cover end surface. A shoulder is formed on the axially outer side of the outer circumferential surface of a head cover. The inner surface of a casing is provided with a circumferentially extending groove. Shear key structure includes a first shear key member disposed in the shoulder and the groove, such that at least a portion of its outer circumferential surface is in contact with the inner circumferential surface of the groove, and a second shear key member disposed adjacent to the first shear key member in the groove, the second shear key member having an axially projecting shoulder, its outer circumferential surface being in contact with an inner circumferential surface of the casing. The first and second shear key members are circumferentially segmented respectively into three or more members, and each member is radially fixed to the casing but not axially fastened to each other, to allow slight displacement between the first and second shear key members by a shear force.

End wall closure apparatus

A welding apparatus and a welding method are employed for laser narrow groove welding which performs welding scanning a laser beam in the welding direction while feeding a solid filler metal into a narrow groove. The welding apparatus includes a laser beam irradiation head having a mechanism periodically oscillating an irradiation point of the laser beam with a predetermined amplitude in the bottom of the groove, and a filler metal control device having a solid filler metal feeder feeding the solid filler metal to the molten pool formed in the bottom of the groove by the laser beam and adjusting the feeding position independent of a motion of the laser beam irradiation head so that the tip position of the solid filler metal detected is constantly positioned in the center of the groove.

Laser narrow groove welding apparatus and welding method

A centrifugal compressor provided with an impeller which is configured to have a plurality of blades arranged at a predetermined interval in a circumferential direction of a hub rotating together with a rotation shaft, in which a blade angle on a shroud side of the blade distributes to have a minimum value at a position between a leading edge of the blade and a midpoint of a camber line on the shroud side, and a maximum value at a position between the midpoint of the camber line on the shroud side and a trailing edge of the blade, and a blade angle of the blade on a hub side distributes so as to have a maximum value at a position between a leading edge and a midpoint of a camber line on the hub side.

Centrifugal compressor

A welding method for an impeller having a plurality of blades, a disc and an exterior body including a shroud welded to the plurality of blades, comprising the steps of:

Welding method and welding apparatus for an impeller

Blades are connected to the surface of a disk and slots are formed in the surface of a shroud, which is opposite from the other surface of the shroud where the blades are to be welded. The blades are arranged on the opposite surface from the slots and a laser beam is applied from the surface in which the slots are formed, to weld the shroud and the blades. Components are installed on the surfaces of the slots on the opposite side from the blades after the blades and the shroud in which the slots are formed are welded. Alternatively, the slots are filled with a material different from that of the shroud, such as a resin. With this configuration, distortion caused by welding heat can be reduced without degrading the fluid performance.

Welding slot sealing structure and welding method

In a high pressure centrifugal compressor, the occurrence of rotating stall noticeable in a comparatively-low specific speed wheel stage is prevented, thereby high efficient fluid performance is obtained and reliability is improved. The centrifugal compressor has a first vaneless diffuser with a constant flow channel height on the downstream side of an impeller, and a second vaneless diffuser in which the flow channel height decreases in a flow direction from an inlet to an outlet on the downstream side of the first vaneless diffuser. These diffusers are combined with an impeller using thick blades.

Centrifugal compressor having vaneless diffuser and vaneless diffuser thereof

A centrifugal compressor is equipped with an impeller having a blade angle distribution that makes it possible to achieve a relatively wide operating range. The blade angle of a shroud side facing a circular plate of a blade is termed a first angle and a blade angle of a hub side disposed at the circular plate is a second. The shroud side is formed in a curved shape having an angle distribution from a front area in a shaft direction toward a centrifugal direction in which the first angle is the local maximum point before a substantially middle portion and the local minimum point after the substantially middle point. The hub side is formed in a curved shape having an angle distribution from the front area in the shaft direction toward the centrifugal direction in which the second angle is the maximum local point before the substantially middle portion.

Centrifugal compressor, impeller and operating method of the same

A multistage centrifugal compressor includes a rotary shaft, and multistage impellers attached to the rotary shaft. Each of the impellers includes a hub, a shroud and blades therebetween in a radial cascade arrangement. An annular suction passage for guiding the fluid flow from the inward radial direction to a blade inlet is disposed upstream of the centrifugal impeller. A diffuser is disposed downstream of the centrifugal impeller. A bend portion is disposed downstream of the diffuser, and a return channel with a guide blade portion is disposed downstream of the bend portion. The annular suction passage at a hub side includes an axial parallel portion.

Multistage centrifugal compressor

In a multistage centrifugal compressor, a plurality of impellers is attached to the same rotary shaft. Vaned Diffusers and vaneless diffusers are used, as diffusers, for respective compressor stages configuring the compressor. The vaned diffusers are continuously used from the first compressor stage to the middle compressor stage, and the vaneless diffusers are used for the last compressor stage and the previous stage. While high efficiency is maintained at the compressor stages having the vaned diffusers, an operating flow range is secured at the compressor stages having the vaneless diffusers.

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Tsuchiura, Japan

Tetsuya Kuwano