| 摘要 |
In a single stage, single suction, high speed centrifugal pump utilizing a closed Francis-vane impeller, operating noise is reduced by encasing a single-step helical gear drive arrangement in a common bearing housing with the impeller's shaft. The operating noise is further reduced by forming the driven helical gear directly on the impeller's shaft to improve dynamic balance, and by mounting a plurality of fins on the bearing housing of the pump to absorb some of the high frequency sound wave energy of the pump, and to translate a further portion of the high frequency sound wave energy into low frequency mechanical vibrations of the fins. Operating noise is further reduced by encasing the fins within a shroud and by providing a fan to blow ambient air by the fins to further disrupt the sound wave patterns emanating from the bearing housing. Operating noise is still further reduced by maintaining the impeller's shaft under tension whereby vibration of the shaft is reduced, as is the noise produced thereby.
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