| 摘要 |
The present invention provides a barrel-type multistage pump in which velocity distribution in the axial direction on the cross-section of a rotating flow channel (8) is uniformed to suppress a fluid loss in the last stage. A barrel-type multistage pump includes: centrifugal impellers (1) that are provided in plural stages; an inner casing (2) that covers the centrifugal impellers (1), and includes diffusers (6) that are provided on the downstream sides of the respective centrifugal impellers (1) in plural stages, return channels that are provided on the downstream sides of the diffusers (6) to guide the flow of a fluid to the centrifugal impeller (1) in the next stage, and return vanes (7) that are arranged at the respective return channels; and a cylindrical outer casing (5) that has a suction pipe (31) and a discharge pipe (41), wherein a cylindrical rotating flow channel (8) connected to the discharge opening (4) is provided between the outer casing (5) and the inner casing (2), a connecting channel (9) is provided between the rotating flow channel (8) and the diffusers (6) to connect therebetween, the shape of the connecting channel (9) is inclined on the suction opening (3) side in the rotary shaft (10) direction, and an outflow position of the connecting channel (9) in the rotating flow channel (8) is located near the central axis of the discharge pipe (41). |
