Power Number measured

Improved cultivation with measured rotor power

Here presented the first set of data point for Power Numbers on small OD 50-60 mm impellers. As to the low Watt consumption for agitation some tolerances is unavoidable. To be continued JAN 2021.

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

Data measured using the Perseus from Cronus-PCS - https://cronus-pcs.com/products/themis-family/perseus/

Magnetic-Bottom-Drive (MBD) driven impellers used.

Conditions: 2 liter of water at 20 °C in 3200 ml SUB, Magnetic-Bottom-Drive, vessel with 3 baffels, with 3 down tubes.

Impeller photo

Impeller name

300 rpm

400 rpm

Kidney
OD 60 mm
3 blades
45 °angle
0.4W
 
4.2
0.5-0.6W
 
2.4-2.9
Kidney
OD 60 mm
3 blades
30 °angle
0.4W
 
4.6
0,5-0,7W
 
2.5-3.0
Pitch
OD 60 mm
3 blades
45 °angle
0.5W
 
5.4
0.8W
 
3.6
Pitch
OD 60 mm
3 blades
30 °angle

30 °angle

0.5W
 
5.2
0.8
 
3.6


Conditions: water at 20 °C in 3200 ml SUB, Magnetic-Bottom-Drive (MBD), vessel without baffles, with 3 down tubes.

Impeller photo

Impeller name

300 rpm

400 rpm

Kidney
OD 60 mm
3 blades
45 °angle
0.2W
 
2.1
0.3W
 
1.4

Kidney
OD 60 mm
3 blades
30 °angle

0.3W
 
3.3
0.3W
1.4

Pitch
OD 60 mm
3 blades
45 °angle

0.3W
 
3.0
0.3W
 
1.6

Pitch
OD 60 mm
3 blades
30 °angle

0.4W
 
4.5
0.5W
 
2.5
Comments:
1. With baffles PN drops with increasing RPM
2. Mechanical friction of BMD is several times higher than agitation losses
3. Measurement tolerance estimated to be ± 20 % and increasing with reduced RPM


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

Conditions: 2 liter of water at 20 °C in 3200 ml SUB, Head-Plate-Drive (HPD), vessel without baffels, with 3 down tubes, impellers mounted on a vertical axle extending down from head plate with no seals for lowest possible mechanical friciton.

Impeller photo

Impeller name

300 rpm

400 rpm

500 rpm

Kidney
OD 60 mm
3 blades
30 °angle

0.2W

1.4

0.3W

1.3

 

 

Kidney
OD 60 mm
3 blades
45 °angle

0.2 W

1.3

0.1 W

0.9

 

 

Kidney
OD 50 mm
3 blades
30 °angle

 

0.2W

2.0

0.3W

1.4

 

Torpedo without impeller
72mm

0.2W

0.8

0.3W

0.5

 

Comments:
1. PN increases slightly with decreasing blade angle
2. Mechanical friction is reduced vastly to HPD head plate bearing friction
3. Measurement tolerance estimated to be ± 20 % and increasing with reduced RPM