| 摘要 |
<p>PURPOSE:To prevent the clinging of a slender material such as hair to a suction port by positioning the suction port above the water surface by adjusting the approach angle of a hollow shaft to the water surface to suck air and dipping the suction port in water in anaerobic operation. CONSTITUTION:When an upper screw 24 is dipped in water, a negative pressure is produced at the tip of the upper screw by the rotation of a hollow shaft 22 and balanced with the negative pressure generated at the tip of a lower screw 23. Consequently, a water current, which intrudes from the dipped suction port 25, descends in the hollow shaft and flows to the lower screw side, is not produced, and operation is carried out as if the suction port is closed. The clinging of a slender material such as hair to the suction port is obviated. Conversely, when operation is carried out with the suction port 25 placed in the air, air is sucked from the suction port by the negative pressure produced by the rotation of the lower screw and discharged into the water from a discharge port at the lower end of the shaft, and desired aerating operation is carried out.</p> |
