| 摘要 |
PURPOSE:To prevent the generation of cavitation by installing a tapered screw on the inlet side of the screw rotors of a screw pump, thus preventing a jet stream from being generated from a gap between the screw rotors and a sleeve. CONSTITUTION:The fluid introduced from a suction flange 1 side is sent under pressure to an outlet flange 5 side by each revolution of a main screw rotor 2 and a trailing screw rotor 3. Between the main and trailing screw rotors 2 and 3 and a casing 4, a minute gap 8 is formed by the existence of screw tapered part (a), and said gap 8 is set so as to increase on the inlet flange 1 side in comparison with on the outlet flange 5 side. Therefore, the pressure Pi at a gap outlet edge 9 increases to suppress a jet stream A generated between the screw rotors 2 and 3 and the casing 4, and generation of cavitation is prevented.
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