Hitachi Plant Engineering Construction Co., Ltd.

Hitachi Plan Engineering & Construction Co., Ltd.

Yukio Murai

Makoto Oonishi

Yutaka Okuno

Naoki Ohkuma

Masayuki Matsuura

Mitsuru Hatanaka

Takashi Fujimoto

The rotary flat membrane disk is constructed in which circular membranes are stretched at both sides of a disk. The disk and the membrane are bonded to each other over the entire periphery by a peripheral bonding part, and they are also bonded to each other by a plurality of partial bonding parts arranged inside the peripheral bonding part. The partial bonding parts are formed like dots of 10 mm in diameter, and are arranged at every 30 degrees on circles of 500 mm and 600 mm in diameter.

Flat membrane disk

The rotary flat membrane separation apparatus comprises: a plurality of hollow rotary shafts; a plurality of rotary flat membrane disks mounted on each of the plurality of hollow rotary shafts at regular intervals, the plurality of rotary flat membrane disks mounted on adjacent two of the plurality of hollow rotary shafts being alternately arranged side by side in equal intervals; and a plurality of collars, each of the plurality of collars being arranged between adjacent two of the plurality of rotary flat membrane disks mounted on each of the plurality of hollow rotary shafts. The apparatus is characterized in that a diameter of the collars is between 0.18-0.34 times a diameter of the rotary flat membrane disks. Thus, the effective membrane area can be as large as possible while preventing the vibration of the rotary flat membrane disks caused by the rotation.

Rotary flat membrane separation apparatus

A rotary shaft is inserted to a tank through a hole formed in a wall of the tank. A casing is provided outside the tank, and the rotary shaft is supported by a bearing arranged in the casing. The casing is watertightly connected to the wall including the hole through a flexible joint. Seal members are arranged in the casing to seal the clearance between the rotary shaft and the casing. A sleeve is fitted on the rotary shaft so that the sleeve is watertightly in contact with at least one of the seal members, and the sleeve can be moved along the rotary shaft to change the seal member in contact with the sleeve. The bearing and the seal member are not affected by the deformation of the tank since the flexible joint connects the tank and the casing, and the rotary shaft can rotate smoothly while securing high sealing quality. The alignment of the axes of the bearing and the hole in the tank can be easy since the bearing is provided outside of the tank, and thus assembly and maintenance of the structure are easy. The tank can have relatively low strength since the tank has not to support the rotary shaft with the bearing; thus the structure can be compact and the cost can be reduced.

Structure for supporting rotary shaft

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Chiyoda-ku, Japan

Yukio Murai