| 摘要 |
PURPOSE:To prevent occurrence of water hammer reliably, by arranging a flywheel near a shaft seal section in an air chamber at a motor section and securing integrally to a rotary shaft. CONSTITUTION:Upon rotation of a rotor 9 at a motor section 1, an impeller 16 sucks/delivers water and a portion of delivered water enters through a back face space 18 into a cavity 19 so as to cool the motor section 1. Rotation of a flywheel 11 causes a circulation flow passing through a through-hole 9a and an air gap section 6a so as to cool the rotor 9. When shaft seal 13 is incomplete, water leaks upward along a rotary shaft 10 to the stator 8 side then stored in a leak water sump 12a through water cut function of the flywheel 11, and said condition is detected through a water leak detector 14. When the operation is stopped, the pump is not stopped abruptly because of the inertia of the flywheel 11, and since the components are arranged in an air chamber 20, rotation of pump decreases gradually thus preventing water hammer effectively.
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