Page 107 - Advanced Mine Ventilation
P. 107
88 Advanced Mine Ventilation
6.5.5 Fan Shaft Horsepower
The power of the main drive corrected by the efficiency of the motor and the efficiency
of the drive is known as the fan-shaft horsepower.
6.5.6 Air Horsepower
Finally, the air horsepower (static or total) is calculated (refer to article 2.8) and divided
by fan-shaft horsepower to obtain the static or total efficiency of the fan. It should be
reasonably high as indicated by the operating range prescribed by the manufacturer.
6.6 Matching a Fan to Mine Characteristics
As discussed earlier, the air volume, Q, and consequent pressure required, P, are estab-
lished for a mine at various stages of its development. To select an efficient fan, the
2
mine characteristic (P ¼ RQ ) is plotted on the same axes as the fan characteristic
as shown in Fig. 6.5. The intersection point of the two characteristics indicates the
pressure and volume at which the fan will work in ventilating the mine. The fan
must have a high efficiency at the operating point. Usually, a very high or a very
low mine resistance is unsuitable. It is a lot easier to design a fan that will suit a
mine characteristic than the other way around.
Figure 6.5 Matching mine characteristics with fan characteristics.
