| 摘要 |
<p>PURPOSE:To stably control the dissolved oxygen concn. by estimating the number of blowers to be operated for supplying the aeration air in the amt. obtained from the estimated oxygen breathing rate and the preset dissolved oxygen concn. and controlling the operation and stoppage of the blowers. CONSTITUTION:When aeration is started, the DO value in the aeration tank is detected, and the detection value is supplied to a DO adjusting part 16 through an input part 13. When the desired DO value is set, the desired aeration air amt. for each aeration tank is calculated by the DO adjusting part 16 and supplied to an air amt. adjusting part 17, and the desired opening degree of an air control valve is obtained. The air control valve is adjusted by an air control valve control part 22 on the basis of the result, and the aeration air amt. is controlled. The desired discharge pressure of the blower is then set and changed by a discharge pressure arithmetic unit 18, the opening degree of a suction valve is changed by a discharge pressure control part 19 to control the discharge pressure. In a number of blowers arithmetic unit 20, the estimated oxygen breathing rate is obtained from the given DO value and aeration air amt., the desired total air amt. of the blowers is obtained, and the start and stop of the blowers are controlled by a number of blowers control part 23.</p> |
