Nirbhay Kumar Sinha

Roll-2013MT0130Mining Machinery Engg.

ISM Dhanbad

MINE FAN

Contents

IntroductionClassification of FanCentrifugal FanAxial Flow FanBooster FanConclusionReferences

Introduction

Ventilation of mines is executed in the pressure method.

Supply of fresh air is provided via ventilating and shaft pits.

Outgoing air flow is exhausted via a skip pit. Supply of fresh air is provided by fans of the

central ventilation. In winter season in case of need, the air

being supplied to the mine is heated in the warm-air furnace (air heater).

Classification of Fan

Mine fans classified in terms of their location: Main fans, which create the primary ventilating

pressure, either forcing or exhausting, that generates the ventilation circuit around the mine.

Auxiliary fans, which generate an air flow beyond the circuit created by the main and booster fans. These fans are used in headings and developments.

Booster fans, Booster fan is a large underground fan which is installed in series with main fan to boost the pressure.

Scrubber fans, which remove dust by passing air through a filter.

Centrifugal Fan

Axial Flow Fan

Centrifugal Fan

The word centrifugal means “moving away from the centre”. Anything including air, if revolved, will have the tendency to leave the centre. There are two rings in the impeller of a centrifugal fan. In between these two rings are the blades of the centrifugal fan. The rings are connected to the shaft by means of spokes. Eye in a Centrifugal Fan Single Inlet and Double Inlet

Centrifugal Fans

Schematic line diagram of centrifugal fan

Types of Blades

The blades of the centrifugal fan can be either radial, backward inclined or forward inclined.

The Centrifugal Impeller

Theoretical Characteristic Curves For A Centrifugal Impeller

Power-volume theoretical characteristics

Actual Characteristic Curves For A Centrifugal Impeller

Actual pressure and shaft power characteristics for centrifugal impellers

Axial Flow Fan

It consists of a shaft with a hub (Boss).

A number of blades are attached to the hub.

Basic components of axial flow fan

Nomenclatures of Axial Flow Fan

1) INPUT CASING

2) IMPELLER CASING

3) ELECTRO MOTOR CASING

4) DIFFUSER

5) IMPELLER

6) ELETRO MOTOR

7) COVER CORE

8) COOLING FAN

9) HYDRAULIC UNIT

10) DIAGNOSTIC TER. BOX

11) JOIN CONNECTION-CASE

12) JOIN CONNECTION-CORE

13) FANS BASE

Classification Based on Attachment of the Blade

Fixed Blades Adjustable Pitch Blades Variable Pitch Blades

Booster Fans

Booster fan is a large underground fan which is installed in series with main fan to boost the pressure.

Booster Fans

Purpose Of Booster Fans For improving the working environment in

case of deep and hot mines through improved air velocities.

for increasing the air quantity in a particular district/panel, booster fans can be used.

Disadvantage Of Booster Fans Sometimes, installation of booster fan in one

district may reduce the flow of air in another district.

Installation Of Booster Fans

Working->

Conclusion

As most of the mine are running on 24 hour basis and once the main mine ventilation fan start it keep running for the years and for any kind of fan shout down, very heavy cost associate with it. Thus this mine ventilation fans has to be very reliable and robust.

And because largest component of the operating cost for mine ventilation is electricity to power the ventilation fans, which account for approximate one third of a typical underground mine's entire electrical power cost. Thus here saving a small % of energy can be very big contribution to the energy conservation.

Centrifugal fans deliver low quantity but at higher head whereas axial flow fans deliver higher quantity at lower head.

References

Deshmukh, D. J. (2008); “Elements of Mining Technology, Vol. – II”; Denett & Co., Nagpur, India.

Banerjee S.P. (2003); “Mine Ventilation”; Lovely Prakashan, Dhanbad, India.

Ghatak, S. (1993); “Mine Ventilation, Vol. II”; Coal Field Publishers, West Bengal, India.

CLARAGE TURBO TECHNOLOGY a.s. J.A. Komenského 1 386 399 01 Milevsko, Czech Republic

“EFFECTS OF BOOSTER FANS IN VENTILATION NETWORKS – COMPUTATIONAL AND EXPERIMENTAL APPROACHES”, Arash Habibi and Stewart Gillies; US Mine Ventilation Symposium; Salt Lake City 2012