UNDERWATER STIRRING DEVICE

摘要

PROBLEM TO BE SOLVED: To enable efficient stir in a water tank and also to prevent a microorganism carrier from being precipitated at a bottom part of the water tank even if the microorganism carrier is charged into the water tank. SOLUTION: Mainly the upper part of the water tank 12 is stirred by the upward stream formed by the first pump blade 28, and on the other hand, upward stream is formed at the outside of a draft pipe 18 by introducing the downward stream formed by the second pump blade 30 to the inside of a draft pipe 18 and discharging from the vicinity of the bottom part of the water tank 12. In this way, the microorganism carrier 14 is not precipitated at the bottom part of the water tank 12 when the microorganism carrier 14 is charge into the water tank 12 since mainly the lower part of the water tank 12 is stirred by the second pump blade 30 and also upward stream is formed at the outside of the draft pipe 18.