72
3 Flow Rates and Pressure Measurements
v max
Fig. 3.7 Air speed profiling in a mine gallery. Note that the operator is located behind the apparatus
so as to avoid distortions in the air current
are several types of anemometer, classified in accordance with the technology they
use: rotating-vane, hot-wire and ultrasonic.
3.6.1 Rotating-Vane Anemometers
The Robinson cup is the type of anemometer usually found in meteorological stations.
This equipment uses the force exerted by the wind on the concave and convex surfaces
of hemispherical cups turning around a vertical axis. However, for mining purposes,
it is common practice to use radial vanes rather than hemispheres (Fig. 3.8). The flow
rate is proportional to the rotation velocity of this axis.
Fig. 3.8 Rotating-vane
anemometer
3 Flow Rates and Pressure Measurements
v max
Fig. 3.7 Air speed profiling in a mine gallery. Note that the operator is located behind the apparatus
so as to avoid distortions in the air current
are several types of anemometer, classified in accordance with the technology they
use: rotating-vane, hot-wire and ultrasonic.
3.6.1 Rotating-Vane Anemometers
The Robinson cup is the type of anemometer usually found in meteorological stations.
This equipment uses the force exerted by the wind on the concave and convex surfaces
of hemispherical cups turning around a vertical axis. However, for mining purposes,
it is common practice to use radial vanes rather than hemispheres (Fig. 3.8). The flow
rate is proportional to the rotation velocity of this axis.
Fig. 3.8 Rotating-vane
anemometer