| 摘要 |
<p>PURPOSE:To discharge the air in a draft tube effectively by coupling a lower draft tube, which forms a ceratation number of a passages with small sectional area, with an upper draft tube coupled with a pump. CONSTITUTION:A lower draft tube 13 forming a certain number of passages 16 with small sectional area is couple with an upper draft tube 12 with comparatively large diameter coupled with a pump 11. When the pump 11 is rotated in the reverse direction to supply the water in a reserve tank to the upper draft tube 12, the air in the upper draft tube 12 is pressed downward and flows alongside the inner surfaces of the passages 16 of lower draft tube 13, and finally discharged out of the lower end.</p> |
