TWO-TIER CENTRIFUGAL PUMP

To provide a two-tier centrifugal pump which can achieve small flow loss (energy loss) of a liquid flowing through a guide blade member to prevent deterioration of pump efficiency.SOLUTION: In a multi-tier centrifugal pump 1, two impellers 4, 5 are attached to a rotor shaft 3 along an axial direction and the impellers 4, 5 are respectively housed in two pump chambers S1, S2 defined in a pump case 2 by a partition wall 21A. A guide blade member 10 is disposed between the impellers 4, 5 located adjacent to each other in the axial direction. In the guide blade member 10, diffuser passages 32 defined by a plurality of diffuser vanes 31 are formed on a surface facing a front surface of a base part. Further, return passages 34 defined by a plurality of return guide vanes 33 are formed on a rear surface facing the partition wall 21A of the base part. On a surface facing the guide blade member 10 of the partition member 21A, a plurality of complementary parts 21b each for filling a step δ formed between the surface and an outer periphery opening end of each diffuser passage 32 of the guide blade member 10 are provided in a protruding manner along a circumferential direction.SELECTED DRAWING: Figure 5 【課題】案内羽根部材を流れる液体の流動損失（エネルギ損失）を小さく抑えてポンプ効率の低下を防ぐことができる２段遠心ポンプを提供すること。【解決手段】ロータ軸３に２つのインペラ４，５を軸方向に沿って取り付け、隔壁２１Ａによってポンプケース２内に画成された２つのポンプ室Ｓ１，Ｓ２の各々に各インペラ４，５をそれぞれ収容するとともに、軸方向に隣接するインペラ４，５の間に案内羽根部材１０を介設して構成され、案内羽根部材１０には、その基盤部の前面に対向する面に複数のディフューザベーン３１で区画されるディフューザ通路３２が形成され、同基盤部の隔壁２１Ａに対向する後面に複数のリターンガイドベーン３３で区画されるリターン通路３４が形成された多段遠心ポンプ１において、隔壁２１Ａの案内羽根部材１０に対向する面に、該面と案内羽根部材１０の各ディフューザ通路３２の外周開口端との間に形成される段差δを埋めるための補間部２１ｂを周方向に沿って複数突設する。【選択図】図５