To prevent reduction of delivery performance by restricting abrasion at an axial direction end surface of a ring 3c of an impeller 3.
A diameter D1 of the impeller 3 is set to be shorter than an outer diameter D2 of pump flow passages 2b and 4b, and the axial direction end surface 3f of the ring 3c is disposed on the inner side of an axial direction end surface of a blade piece 3a, that is of an axial direction end surface 3g of the impeller 3. Contact slide of the axial direction end surface 3f of the ring 3c corresponding to a blade groove 3b as a most part of the ring 3c of the impeller 3, that is a part where circumferential speed becomes the largest, with axial direction end surfaces of a pump casing 2 and a pump cover 4 is thus eliminated. Slide abrasion at this part in a conventional turbine pump is restricted, and reduction of delivery performance of the turbine pump 1 can be securely prevented.
MORI YUKIO
ITO MOTOYA
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