A contra-rotating system
consists of two single stage opposite handed impellers
rotating in opposed directions.
Compared to a single stage
system
The contra-rotating system develops approximately
2-3 times the static pressure of a single stage
impeller system of the same diameter and speed.
The two-stage system uses 5-10% less power and is
quieter than a single stage system producing the
same work at the same diameter.
A two-stage system delivers a parallel non
turbulent air stream, contrary to a single stage
impeller which has a rotating turbulent air stream.
In operation The air flow can be regulated by idling one stage. A
flow reduction of 35% and a power reduction of 50% is
possible without losses.
If necessary more stages can be added if pressure
demands are higher than a two-stage system can meet.
Selection The selection of the two axial impellers is based upon
the Multi-Wing standard range which offers many possible
combinations. The Multi-Wing Optimiser selection
programme
produces customised performance curves at any rpm,
diameter and power consumption within the Multi-Wing
impeller
system. This information is based upon a large number of
practical tests in the Multi-Wing
Wind Tunnel.
