STIRRING DEVICE FOR ANAEROBIC DIGESTION TANK

摘要

PURPOSE:To enable stirring with good energy efficiency by generating the annular rotating motion to raise the carrier deposits floating on the liquid in a digestion tank by a stirrer erected at the center of the tank and to lower the same in the peripheral edge part. CONSTITUTION:The anaerobic digestion tank 1 having an approximately circular horizontal section contains the deposits of the small granular particles having the characteristic to be stuck with anaerobic bacteria and to float in sewage. The water in the tank 1 is stirred by the slow speed paddle type stirrer 2 having an approximately perpendicular shaft 2a at approximately the center of the horizontal section of the tank. Paddles 3a-3l of the stirrer consist of plural pieces and are respectively fixed to the shaft 2a apart from each other at proper intervals therebetween. The paddles are so formed that the sectional shape perpendicular to the longitudinal direction of the paddles (radial direction of the tank 1) has a downward grade in the part near the revolving shaft with respect to the rotating direction of the paddles and has an upward grade in the part further from the revolving shaft. The stirring with good energy efficiency is made possible by such relatively simple and inexpensive stirring device.