How to size a main fan ?

Ventilation studies are carried out, for periods that best characterize the evolution of the mine, in order to determine the values of air flow rate and total pressure corresponding to the points where the fan will have to operate.

For example, the case of a ventilation study that led to the operating points shown in the figure below:

SUBROCA BLOG

P1                    at the start of the installation in year A

P2 et P3           accidental operating points

PM                   final points from year A+2 onwards

 

If we set as a requirement

To have in PM a yield close to the maximum (84-85%)

To make sure that P1 does not enter the pumping

A range ABCDEA can be defined, the characteristics of which must be guaranteed by the manufacturer.

P1                    at the start of the installation in year A

P2 et P3           accidental operating points

PM                   final points from year A+2 onwards

 

If we set as a requirement

To have in PM a yield close to the maximum (84-85%)

To make sure that P1 does not enter the pumping

A range ABCDEA can be defined, the characteristics of which must be guaranteed by the manufacturer.

SUBROCA BLOG

On the basis of this information, the manufacturer will supply a fan whose characteristics are such that the ABCDEA zone is not amputated:

  • Nor by the pumping limit curve (along the ABC line)
  • Neither by the curve corresponding to the nominal power of the motor (along the BCD line)

Installation of measurements of aerodynamic characteristics

These measurements relate to the two main characteristics of the fan from the ventilation point of view, i.e. the air flow rate and the total pressure.

A distinction must be made between the types of use of the measuring probes :

  • Recording of flow rate and total pressure during operation,
  • Detailed measurements for checks and calibrations, upon acceptance of the installation.

The SUB’ROCA engineers are at your disposal to assist and advise you in the dimensioning of your ventilation installations. Whether your project concerns a meshed network in an underground mine or a complex digging project in another environment, our teams have the technology to calculate the air requirements and performance necessary to ensure ventilation that complies with the health and safety of personnel.