PURPOSE: To enable to increase the pump head of a centrifugal pump, by reducing leakage and loss of pressure through provision of a radial clearance between the casing wall and the outer circumference of an impeller.
CONSTITUTION: The object of this invention is to prevent leakage of fluid to spaces 4 formed between a volute casing 3 and an impeller 1 by forming a ring- like projection 6 respectively around the outer circumference of a front and a rear shrouds 1a, 1c of the impeller 1 and modifying the shape of the volute casing 3 facing the front and rear shrouds 1a, 1c such that gaps 5 are formed between the volute casing 3 and the shrouds 1a, 1c. Since leakage flow of fluid is reduced by employing such an arrangement, it is enabled to obtain a pump having a high pump head ratio in no-discharge operation of the pump.
OKAMURA TOMOYOSHI
TAKAGI TAKEO
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