| 摘要 |
PROBLEM TO BE SOLVED: To provide an impeller capable of improving oxygen supply efficiency to water to be treated without increasing power.SOLUTION: Two main agitation blades 3, 3 adjoining with each other are coupled by a tie plate 4 disposed with a gap d to a vertical shaft 2, and an auxiliary agitation blade 5 projecting above an upper surface of the tie plate 4 is provided. Water to be treated entering above the tie plate 4 from the gap d is accelerated in a divided state by both the main agitation blades 3 and the auxiliary agitation blade 5, and are splashed into the atmosphere to reduce the sizes of the splashes by submerging and rotating an impeller 1A having such a structure so that the tie plate 4 recedes below a water surface. Accordingly, the contact area of the splash with the atmosphere is increased, and oxygen supply efficiency is improved. The agitation of the water to be treated is performed only by the main agitation blades 3 below the tie plate 4 by causing the auxiliary agitation blade 5 not to project below the tie plate 4. Accordingly, a rise in power due to agitation resistance is suppressed. |
