Patent ID: 9249804
Filing Date: 2016-02-02
CPC Classification: F04D,F05D

Claim Text:
1. A barrel-type multistage pump comprising: centrifugal impellers that are provided at a rotary shaft in plural stages; an inner casing that covers the centrifugal impellers, and includes diffusers that are provided on the downstream sides of the respective centrifugal impellers in plural stages, return channels that are provided on the downstream sides of the diffusers to guide the flow of a fluid to the centrifugal impeller in the next stage, and return vanes that are arranged at the respective return channels; and a cylindrical outer casing that has a suction pipe as the inlet and a discharge pipe as the outlet of the fluid, wherein a cylindrical rotating flow channel connected to a discharge opening is provided between the outer casing and the inner casing, a connecting channel is provided between the rotating flow channel and a last stage diffuser of the diffusers to connect therebetween, the shape on a meridional plane of the connecting channel is inclined on a suction opening side in the rotary shaft direction, and an outflow position of the connecting channel in the rotating flow channel is located near the central axis of the discharge pipe, and a plurality of guide blades are provided in the connecting channel.