PURPOSE: To maintain the purification performance of the device and simultaneously prevent the death of fishes due to oxygen deficiency by effectively multiplying microorganisms in a microorganism culture tank for maintaining the purification performance of the device, and operating an auxiliary air-supplying means for the lowering in the performance of an air-supplying means inserted into a circulation flow route in response to a signal from an air flow detecting means to supply air (oxygen).
CONSTITUTION: The device comprises a water press-supplying means 3 and a microorganism culture tank 5 successively installed in a forced circulation flow route for circulating water in a tank, an air supply means 4 for sucking and supplying air with the fluid energy of the circulation flow for supplying air in the microorganism culture tank 5, an optically air flow-detecting means 10 arranged in the air inflow route of the air-supplying means 4, and an auxiliary air-supplying means 11 for forcibly supplying air into the air supplying means 4 when receiving the output of an air shortage signal from the air flow-detecting means 10.
KOBAYASHI IKUO
TAKAHASHI YUTAKA
HATSUTORI MASANARI
