| 摘要 |
PURPOSE:To prevent a mechanical seal from being damaged with foreign objects in a water current, by providing a shut-off wall covering the mechanical seal on the boss section of an impeller, and communicating the inside of the shut-off wall with a suction passage on the opposite impeller side of the suction passage. CONSTITUTION:A shut-off wall 17 covering a rotary shaft 6 and also covering a mechanical seal 8 provided on the rotary shaft 6 is formed at the drive section side of a boss section 9 in an impeller 5. And, the inner space of the shut-off wall 17 and a suction passage 3 are communicated with each other through a communicating passage 18 formed on the opposite impeller side of the suction passage 3. With this arrangement, since solid foreign objects included in a water current flowing through the suction passage 3 never reach the mechanical seal 8, it is possible to prevent seal surfaces 12a, 15a of the mechanical seal 8 from being damaged with the bite of the foreign objects.
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