pump

Abstract

The pump disclosed herein includes a casing and an impeller, the impeller having a first shroud (720) covering the blade portion (710). The casing has a groove (312) and an inner wall portion (313), the groove (312) for insertion of the front end (722a) of the suction nozzle portion (722) of the first shroud (720), and the inner wall portion (313) being located closer to the inner circumference than the groove (312). Between the casing and the first shroud (720), a return path (360) with a labyrinth structure (361) on the inner circumference is formed, the labyrinth structure (361) being formed by the suction nozzle portion (722) and the groove (312). An extension (726) is formed in the first shield (720), and the aforementioned extension (726) has a facing surface (726a) facing the end face (313a) of the blade portion (710) side in the axial direction of the inner sidewall portion (313).

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