Vertical Shaft Aerator

- Rag free during operation.
- Pumping capacity of up to 6 [m3/s].
- Oxygen transfer rate of up to 2.2 [kgO2/kWh] at operating speed.

Trustworthy bacterial oxidation of wastewater

  • Rag free during operation.
  • Pumping capacity of up to 6 [m3/s].
  • Oxygen transfer rate of up to 2.2 [kgO2/kWh] at operating speed.

Principle and Function

The Wamechsi Vertical Shaft Aerators are ideal for the bacterial oxidization of effluent by the transfer of oxygen from atmosphere and to provide the necessary turbulence to maintain homogenization and mixing between the live medium, the polluting elements and the water thus oxygenated.  Oxygen transfer rates are proportional to the power absorbed at the aerator shaft and this, in turn, is governed by the size, speed and immersion of the turbine. 

Wamechsi aerator impellers are rag free in operation, have a high pumping capacity suitable for low and high energy applications and produce a stable wave formation with a minimum of erratic splashing and negligible air bone mist.

An additional feature of Wamechsi aerators is that the design is such that power input, and hence oxygenation input, can be reduced to approximately 80% of the design figure by revising direction of rotation.

Technical Data: (Typical)
Speed of Rotation:                  

Tip Speed of Impeller:             

Diameter of Impeller:              

Material of Impeller:                

Diameter of Shaft:                   

No. of Blades:                          

Installed Power:                                  

Motor & Gearbox Data:
Make:                                       ???

Rated Motor Power:                

Gearbox Ratio:                       

Gearbox Service Factor:          1.5

Efficiency of Electrical Motor:  

Electrical Supply:                      220 ????? ??, 50 [??]

Advantages of the Wamechsi Group Vertical Shaft Aerator:

  • -          Fully accessible without the need of draining the tanks.
  • -          Rag free during operation.
  • -          High pumping capacity suitable for low and high energy applications.
  • -          Produce a stable wave formation with a minimum of erratic splashing and negligible air bone mist.
  • -          Oxygen transfer rate of up to 2.2 [kgO2/kWh] at operating speed.
  • -          No bearing in contact with the waste water.
  • -          Slow speed, at a range of 38 – 62 [rpm].

The Wamechsi Group Vertical Shaft Aerator consists of the following key parts:

-          Motor & Gearbox

The installation of the electrical motor and gearbox is used to rotate the impeller through the waste water and ensuring that oxygen is generated.  An inline vertically mounted electrical motor is mounted in the top of the aerator to transfer the power through the gearbox and shaft to the impeller. The motor and gearbox selection is based on the specific aerator required for installation.





-          Coupling

The mechanical coupling connects the shaft to enable the transmission of rotational power to the other, in this case the motor to the gearbox and the shaft. The coupling incorporated onto a high-speed shaft also allows for a degree of misalignment.

-          Drive Shaft

The driveshaft is used to transfer the rotation from the gearbox to the impeller.  The shaft size and specifications are calculated in order to handle the required power transfer to the impellers.




-          Impeller

The impeller rotates in the waste water in order to keep the waste water moving and the air from coming in contact with a larger surface area. The impeller is usually completely open. Liquid is introduced to the aerator impeller in a predominantly vertical direction, then accelerated by the impeller vanes, and finally discharged in an essentially horizontal direction at the impeller rim. The discharge flow can be considered as rapid flow and slow moving liquid in the vessel can be considered as tranquil. Transition flow from rapid to tranquil flow occurs through the hydraulic jump. Therefore, a circular hydraulic jump is formed around the aerator where the ambient air is entrained and dispersed into bubbles in the hydraulic jump.























Speed of Rotation


38 - 62

38 - 62

38 - 62

38 - 62

38 - 62

38 - 62

38 - 62

38 - 62

38 - 62

Tip Speed