| 摘要 |
A low speed type underwater aerator which enables water cooling of an inverter without installing an additional cooler, prevents floc in wastewater from being broken without deteriorating the output of a motor, and allows a mixture of air and treated water to be radially diffused far away by specifying the number of revolutions of an impeller, and a controlling method of the low speed type underwater aerator are provided. A low speed type underwater aerator comprises: a suction housing(10) having an inflow port(11) such that wastewater flows into an aeration tank(1); a discharge housing(20) which is installed on a lower part of the suction housing, and has a discharge port(21) to discharge wastewater; an impeller motor(30) fixed onto the suction housing by a bracket(31) such that a shaft of the impeller motor is directed downward; an axial flow type impeller(40) installed in an inner space part(S) formed by coupling of the suction housing and the discharge housing and rotated by power of the impeller motor; a diffuser(50) installed on a lower part of a hub of the impeller to diffuse oxygen supplied from an oxygen supply pipe(2) through diffusion ports(3) radially formed; and an inverter(60) embedded in the impeller motor to control the number of revolutions of the motor, wherein the impeller is directly connected to the impeller motor, the number of blades of the impeller is 3 to 4, the impeller motor has 6 poles as 3 pairs of N and S poles, and the impeller is controlled by the inverter such that the number of revolutions of the impeller is reduced to 200 to 400 rpm. |
