| 摘要 |
In the present invention, an impeller (5) has a plurality of vanes (6), the inner ends of a subset of which are joined to a rotary shaft (7), and the outer ends of each vane are joined to an annular connection section (8). The impeller (5) is supported rotatably in a pump chamber (2). A pedestal (17) is formed by the floor wall of a housing (1) protruding upwards, and has a cylindrical outer peripheral surface corresponding to a space region on the inside of the annular connection section. The upper surface of the pedestal is provided with a bottom bearing (10) that supports the bottom end of the rotary shaft of the impeller. A sealing member (20) is disposed at the bottom of the vanes, and seals the space of the inner region of the annular connection section leaving an opening (21) at the periphery of the rotary shaft. The diameter (D) of the pedestal and the radial gap width (Cr) between the annular connection section and the pedestal fulfill the relationships of 13.5 mm = D = 15.0 mm and 0.20 = Cr/D = 0.28. The present invention suppresses hemolysis stemming from the shear stress accompanying impeller rotation, while securing the effect of increasing flow speed in the vicinity of the lower bearing by means of the sealing member.
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