Vortex Degritter Paddle Mixer

Trustworthy separation of grit from wastewater

Trustworthy separation of grit from wastewater

  • Grit separation efficiency of up to 90 [%] for particles larger than 200 [μm].
  • High grit discharge capacity with submersible pump.
  • Effective vortex de-gritting system proven on several plants.

Principle and Function

The Wamechsi Group Vortex De-Gritter is used for grit removal in a waste water treatment plant (WWTP). The paddles are rotated by a motor and gearbox which helps generating the vortex in the system. The paddles are in contact with the waste water and the rotation of the paddles induce a vortex in the fluid inside the de-gritting chamber.

The grit is separated from the fluid by using the principle of the different settling velocities of the fluid and the grit.  The grit is denser and therefore it will settle at a lower velocity than the water causing the grit to drop to the bottom of the de-gritting chamber where it is captured in order to be removed from the sewage works.

Thecnical Data (Typical)

Vortex Tank Diameter:                        

Operating Speed of Paddles:             

Influent Flow Rate:                             

Material of Headstock:                        

Material of Paddles & Discharge:       

Total Mass of Unit:                               

Grit Separation Efficiency:                   

Motor & Gearbox Data:

Make & Model:               

Rated Motor Power:      

Gearbox Rating:         


Gearbox Service Factor:         

Electrical Supply:         


The maximum noise level is 77 [dB]. If the noise level exceeds 77 [dB] immediate attention should be given in order to avoid damage to the machine.

Working Environmental Conditions

-          Environment Type: Industrial, wet, pollution degree 3.

-          Temperature: From -20 [˚C] to 40 [˚C]

-          Humidity: From 40 [%] to 100 [%]

The Wamechsi Group Vortex De-Gritter consists of the following key parts:

-          Motor & Gearbox

The installation of the electrical motor and gearbox is used to rotate the paddles through the fluid.  A vertically mounted electrical motor is mounted in the top of the vortex de-gritter to transfer the power through the gearbox and shaft to the impeller.  The motor and gearbox selection is based on the specific de-gritting chamber size.

-          Driveshaft

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

-          Paddles

The paddles of the machine are in contact with the water to ensure that a vortex is induced in the waste water inside the de-gritting chamber.  The Paddles are fixed on the paddle side shafts with a rotational coupling allowing the paddles to rotate to prevent damage to the machine in the case of debris in the de-gritting chamber.

Figure 1: Typical Wamechsi Paddle Headstock

Wamechsi Paddle Mixer Capacity and Sizes:
The following table presents a possibility to select the right size vortex de-gritter depending from the influent flow conditions.

Vortex Tank Diameter

Influent Flow Rate

Paddle Speed

Grit Hopper Volume







235 - 430


2.2 - 3.0


400 - 760


3.9 - 5.2


680 - 1220


6.7 - 8.5


1080 - 1870


10.6 - 13.0


1870 - 3160