STRUCTURE FOR SUPPORTING ROTARY SHAFT

摘要

A rotary shaft (20) is inserted to a tank (12) through a hole (22) formed in a wall of the tank (12). A casing (30) is provided outside the tank (12), an d the rotary shaft (20) is supported by a bearing (76) arranged in the casing (30) . The casing (30) is watertightly connected to the wall including the hole (22) through a flexible joint (34). Seal members (50, 52, 60) are arranged in the casing (30) to seal the clearance (22a) between the rotary shaft (20) and the casing (30 ). A sleeve (64) is fitted on the rotary shaft (20) so that the sleeve (64) is watertightly in contact with at least one of the seal members (50, 52, 60), and the sleev e (64) can be moved along the rotary shaft (20) to change the seal member (50, 52, 60) in contact with the sleeve (64). The bearing (76) and the seal member (50, 5 2, 60) are not affected by the deformation of the tank (12) since the flexible joint (34) connects the tank (12) and the casing (30), and the rotary shaft (20) c an rotate smoothly while securing high sealing quality. The alignment of the ax es of the bearing (76) and the hole (22) in the tank (12) can be easy since the bearing (76) is provided outside of the tank (12), and thus assembly and maintenance of the structure are easy. The tank (12) can have relatively low strength since the tank (12) has not to support the rotary shaft (20) with t he bearing (76); thus the structure can be compact and the cost can be reduced.