Low Speed Vertical Shaft Surface Aerator
Low Speed Surface aerator ( AIRMAX )
Low Speed surface aerators are used for aeration and mixing .
The Low Speed Surface aerator AIRMAX presents all the required qualities for efficient aeration of biological plants.
The main advantages of the low speed surface aerator are:
- Very high oxygen input in standard conditions per unit
- Stable oxygen input in time
- Nearly no maintenance
- Very high efficiency>2kgO2/kwh ac to EN 12-255-15 due to very slow rotaion speed
KAMPS ensures the engineering, manufacturing, supply and installation of the aerators.
General Surface aerators will be mechanical aerators of clog freedesign suitable for installation on reinforced concrete supporting structures within the aeration tanks. Each assembly will be completed weather proof and satisfactory for operation conditions duty and environment specified.
The impeller that can be in contact with sewage water will be obligatory in carbon steel protected by epoxy coating. Each unit shall be individually driven by an electric motor through a reduction gearbox. The aerators are low-speed, open type use for oxidation ditches, tanks or lagoons. Vertical aerators will have rigid coupling between gearboxand aerator shaft.
The aerator installation will generally consist of the following parts:
Impeller Intermediate shaft
Foundation plate
Rigid coupling between shaft and gearbox
Heavy duty gearbox
Flexible coupling between gearbox and E motor
E-motor
Construction
In order to reach a no clogging impeller, the impeller has to be a flat base plate with anti clogging blades. The number of blades is minimum 12and each blade is oriented with an angle of 30° in order to reach a good spread of splashing water in the space around the aerator. The impellers have to be provided with three lifting lugs for easy installation. The shaft is connected to the drive unit by means of a rigid coupling. All parts are connected with strength fastenings hot galvanized bolts. The foundation plate is provided with hot galvanized bolts to enable the horizontal adjustment during erection. Those bolts will be embedded in concrete deck that ensures a robust and vibration free mounting construction. The coating of the aerator is epoxy suitable for sewage water. The minimum protection requirement is after SA2½ blast cleaned two layers of minimum 150 microns epoxy coating.
Impeller in polyester is not allowed
Design :
The diameter of the aerator must be designed as following:
D = 0,15 x(SOTR) 1/2 + 0.8(*)
where: D= diameter in m
SOTR = Standard Oxygen Transfer Rate in kg O2/h in drinking water
According EN 12-255-15
Those diameters can be higher to achieve a much better mixing.
(*) For Carrousel system, replace 0.8 by 1.
The peripheral speed of the aerator is not exceeding 5.5 m/sec so that the possibility of sludge break-up is kept to a minimum. The complete units will be capable of being started with aerator at the operating depth of submergence. The up-trust of the aerator assembly will be equal or lower than the total weight of the impeller assembly in order to guarantee the longest life time of the gearbox. The mains characteristics are: Low axial and radial forces ( no up-trust above impeller weight) Optimum efficiency Propulsion capacity and mixing capacity in oxidation ditches No-clogging of the aerator
Hardly any maintenance Accuracy of performance is according ATV M 209 or EN 12-255-15. Gearboxes The gearbox unit will have a design life of not less than 100.000 hours according to AGMAand be selected in accordance with recommendations for power transmission calculation. For the selection of the gearboxes, the service factor is minimum 1.75 between nominal AGMA power of gearboxes and shaft power for oxidation ditches, and 1.5 for complete mixed tank. Those factors are respectively 2 and 1.75 in case of oxidation ditches. Gearboxes will be designed for continuous 24 hours/day operations and be classified for medium shock loading. The efficiency of the gearbox is not less than 99% per stage. The lantern on the gearbox is an obligation It is possible to dis-assembly the gearbox on site. The gears and pinion shafts are manufactured from alloy steel, precision grinded to ensure high efficiency, maximum tooth strength low noise and vibration level.