Power Number measured

Improved cultivation with measured impeller power

Vastly improved Np data (obtained december 2022) points for Power Number's (Np) on "small" OD 50-60 mm impellers.

Impellers to be found on - https://cercell.com/support/cellvessel-details/impeller-available/

Rotor Watt consumption (W) measured with high precision by Cilix - https://cronus-pcs.com/products/themis-motor-drive

Conditions: 2 liter of tap water at 20 °C in 3,200 ml CellVessel SUB, Head-Plate-Drive (HPD), vessel with 3 baffels, with 3 down tubes (deep tubes or sensors).

Impeller photo

Impeller name

300 rpm

400 rpm

Kidney
OD 60 mm
3 blades
45 °angle
0.2 W
 
1.9 Np
0.4-0.5 W
 
2.0 Np
Kidney
OD 60 mm
3 blades
30 °angle
0.1 W
 
1.1 Np
0.2-0.3 W
 
1.1 Np
Pitch
OD 60 mm
3 blades
45 °angle
0.1-0.2 W
 
1.4 Np
0.3-0.4 W
 
1.4 Np
Pitch
OD 60 mm
3 blades
30 °angle

30 °angle

0.1 W
 
1.0 Np
0.2 W
 
0.9 Np


Conditions: water at 20 °C in 3,200 ml CellVessel SUB,
Head-Plate-Drive (HPD), vessel without baffles, with 3 down tubes.

Impeller photo

Impeller name

300 rpm

400 rpm

Kidney
OD 60 mm
3 blades
45 °angle
0.2 W
 
1.8 Np
0.4-0.5 W
 
1.9 Np

Kidney
OD 60 mm
3 blades
30 °angle

0.1 W
 
1.0 Np
0.2 W
1.0 Np

Pitch
OD 60 mm
3 blades
45 °angle

0.1-0.2 W
 
1.3 Np
0.3 W
 
1.3 Np

Pitch
OD 60 mm
3 blades
30 °angle

0.1 W
 
0.9 Np
0.2 W
 
0.8 Np
Comments:
1. With baffles PN drops with increasing RPM
2. Mechanical friction of the MST used for MBD is several times higher than agitation losses
3. Measurement tolerance estimated to be <± 10 %


Head-Plate-Drive (HPD) parts used for testing.

Conditions: 2 liter of water at 20 °C in 3,200 ml CellVessel SUB, Head-Plate-Drive (HPD), vessel with/without baffels, with 3 down tubes, impellers mounted on a vertical axle extending down from head plate with no bearing seals for lowest possible mechanical friction.

Impeller photo

Impeller name

300 RPM no baffels

400 RPM no baffels

300 RPM with baffels

400 RPM with baffels

 

Kidney

OD 60 mm

3 blades

30 °angle

0.1 W

0.9 Np

 

0.1-0.2 W

0.8 Np

 

 0.1 W

1.3 Np

0.2 W
0.9 Np

 

Kidney

OD 60 mm

3 blades

45 °angle

0.1-0.2 W

1.8 Np

 

0.3-0.4 W

1.7 Np

0.2 W

 2.1 Np

 

0.4 W

1.8 Np

 

Kidney

OD 50 mm

3 blades

30 °angle

0.1 W

1.5 Np

0.1 W

1.1 Np

 

0.1 W

1.6 Np

 

0.1   W

1.1 Np

 

Torpedo without impeller

72mm

0.1 W

0.15 Np

 

0.1 W

0.15 Np

 

0.1 W

0.2 Np

 

0.1   W

0.15 Np

Comments:
1. Np decreases slightly with decreasing blade angle
2. Mechanical friction is reduced as to HPD head plate bearing house without seal / seal-friction
3. Measurement tolerance estimated to be <± 10 %