| 摘要 |
PURPOSE:To improve a performance and prevent generation of cavitation by restricting the face vibration of a side plate by a method wherein a clearance is provided by drawing out the attaching part of the rear face side plate of the impellor outwardly and attaching an auxiliary plate, drawn toward the suction side, to the inside of the rear face side plate. CONSTITUTION:A vane 2 is provided with protuberances at the both sides thereof and these protuberances are inserted into holes provided on the front and rear side plates 1, 3 to form integrally by connecting the inserting parts by projection welding. Subsequently, the periphery of the attaching part of the rear face side plate 3 is drawn outwardly to provide a step at the inside thereof, the auxiliary plate 4 is attached to the stepped part so as to face it toward the suction side and the clearance 5 is formed between the periphery of the inserting surface and the side plate 3 so as to locate the clearance toward the suction side. The position of the clearance 5 is coinciding with a position generating cavitation, therefore, the cavitation may be restricted by supplying pressurized water to a part having a negative pressure in the clearance 5 from the lower side of the vane. |
