| 摘要 |
<p>PURPOSE:To prevent intrusion of water into a pump, by forming a suspension wall around a pump set in a water intake tank having a free water surface so as to form a closed space above the water surface, and communicating the closed space with the atmosphere only via a check valve so that the water level in the closed space is kept always higher than the free water surface. CONSTITUTION:A water intake tank comprises an outer wall 1, a pump 2 and a swirl preventing plate 3, and water is supplied from an external water source to the tank via an intake passage 4. Here, a depending wall 8 is formed to depend downward from the lower surface of the base of the pump disposed at an upper portion of the intake tank, so as to form a closed space 9 defined by the depending wall 8, other wall surfaces and water surface 14 around a suction casing. The closed space 9 is communicated with the atmosphere only via a pipe 11 having a check valve 10. By employing such an arrangement, when the water level 25 of the free water surface 5 at the intake passage 4 is raised, air in the closed space 9 is discharged to the outside via the pipe 11, so that the water level 24 of the water surface 14 is also raised. On the other hand, when the level 25 of the water surface 5 is lowered, the water level 24 of the water surface 14 is kept high since intrusion of air into the closed space 9 is prevented by the check valve 10.</p> |
