MACHANICAL VENTILATION 0030.pptx, MINING ENGINEERING
- 1. MACHANICAL VENTILATION NAME-JYOTI RANJAN NAYAK REGD NO - F21159010030 BRANCH. - MINING ENGG.. SEM. - 4TH. SEM.
- 2. • INTRODUCTION • CLASSIFICATION OF FAN • CENTRIFUGAL FAN • AXIAL FLOW FAN • BOOSTER FAN • INSTALATION OF BOOSTER FAN • CONCLUSION • REFERENCES CONTENT
- 3. INTRODUCTION. • Mechanical ventilation is used to supply air in areas where the miner operates, and this air is used to remove dust particles, noxious gases and regulation of temperature • Natural Ventilation sometimes in adequate and unreliable for mine ventilation. • Hence, mechanical ventilation is a common practise in the mines • A fan may force the air in a mine that is called forcing fan or it may suck of the air
- 4. CLASSIFICATION OF FANS • Based upon the design of fans,fan are of two types 1. Centrifugal Fan-A centrifugal fan is a mechanical device for moving air or other gases in a direction at an angle to the incoming fluid 2. Axial Fans-Axial fans create airflow with a high flow rate, meaning they create a large volume of airflow. However, the airflows they creat 3. Booster Fan-A duct booster fan is a small fan that can fit inside an air duct and aims to increase the airflow to more distant parts of UG mines
- 5. CENTRIFUGAL FAN • A centrifugal fan essentially consist of a wheel Carring blades at the periphery. • When the blade moves with the rotation of the Fan, it tends to drive the particle in a circular path towards b • The centrifugal Fon wires the centrifugal power supplied from the rotation of impellers to increas • the kinetic energy of am… The speed of the Fan varies from 100 to 300 rpm. • In actual fractice the blades of the Fan exactly radial, but either are not Curved backward or curved forward, through the backward curved blade types are common
- 6. SCHEMATIC LINE DIAGRAM OF CENTRIFUGAL FAN
- 7. TYPES OF BLADE • Base on the shape of the blade centrifugal fan diveded into 3 types. 1. Forword bladed fan 2. Radial bladed fan 3. Backward bladed fan
- 8. THE CENTRIFUGAL IMPELLER • The centrifugal impeller critical components of the deep-sea mining pump. • The impeller converts mechanical energy into kinetic, pressure, and potential energy of the slurry by its rotation
- 9. THEORACTERISTICS CHARECTERIS CURVES FOR A CENTRIFUGAL IMPELLER
- 10. ACTUAL CHARACTERISTICS CURVES FOR A CENTRIFUGAL IMPELLER
- 11. AXIAL FLOW FAN • An air screw “Fans or an axial Flow Far pushed the air forward on the direction parallel to the axis. i.e. axially, without changing the direction of air current unlike in the centrifugal fan • If the nut is confined to place and made to ono rotate, the bolt travels along its axis. • When the not is rotated in reverse direction the travel of bolt is in opposite direction. • Quantity circulated depend on the speed of the blade tips and as compared to the centrifugal fan a much higher peripheral speed is needed for creating the Same water gauge • The higher peripheral speed of the blade more & the noise, permitted Limit of the speed of blade tips 4200 m/min. • Pressure that may generated in nearly 12.5cm of water gauge.
- 12. AXIAL FLOW FAN • It consists of a shaft with with a hub(Boss) • A numbers of blades are attached BASIC COMPONENTS OF AXIAL FLOW FAN
- 13. NOMENCLATURES OF AXIAL FLOW FAN
- 14. NOISE REDUCTION IN AXIAL FAN Some situations require noise reduction by the axial fan (ex.: fan installed inside mine; vent near urban areas, ….). • In this case, the manufacturers provide devices that reduce the noise emission of the fans. These devices cause some loss of flow, which must be checked with the manufacturer.
- 15. FAN LAWS • LAW-1. The quantity of air delivered varies. Directly as fan speed Q N ∝ Q1/N1=Q2/N2 • LAW-2. Pressure foreduced developed varies of the square of the Fan speed of the quantity. P^2 N^2 Q^2 ∝ ∝ • LAW-3 Power required to drive the fan varies as cube the fan speed or quantity. • Pw N^3 Q^3 ∝ ∝ • power (PW) = pressure x Quantity Pw= P W ∝ • where, Q = Quantity of aira and N= Fan speed.
- 16. FAN DRIFT The short tunnel connecting the upcart shaft with the exhaust fan. The enclosed are tight passage, road and gallery from the mine to the fan. The passage or duct for the intake of a ventilating fan on a mine An airway leading from a mine shaft, or airway, to a fan.
- 17. FAN DRIVE • It is a fluid clutch (tight) to adequately control rotation frequency of the fan for engine cooling. • Temperature sensitive bi-metal which detects air temperature passing through the radiator, controls working silicon oil Volume in the drive so that Fan rotaction frequently is kept adequately in controlled manner.
- 18. EVASEE • An Evasee is a device which is usually attached at the outlet of the mine fan to recover some of the wasteful energy to the useful pressure energy • This recovered pressure energy in turn increases the air flow rate in the mine ventilation syste DIFFUSERS • It is a device for deflecting air from an outlate in various direction
- 19. CLASSIFICATION BASED ON ATTACHEMENT OF THE BLADE
- 20. BOOSTER FANS • Booster fan is a large underground fan which is installed in series with main fan to boost the pressure • Sometimes the air pressure provided by the main for in sufficient to create the needs of the whole district. Or • • Beostor fan is fan which used in underground for boosting up or supplementing the air high in a resistance split in which the ventilation produces. By the main Fan is in adequate.
- 21. BOOSTER FAN 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
- 22. EFFECT OF BOOSTER FAN ON MINE VENTILATION • The immediate effect is fall in the resistance against which the if the main fan has to work, so that if the main fan pressure is constant, increase volume of air flow through the mine. • If the resistance of all the our ways remain in constant there is increased in pressure drop drawn in the trunk airways. So that the pressure difference between the intake and return at the point of Spliting set reduced. • If the booster fan pressured is very high. All the pressure due to the main “fan may be lost in trunk airways with the result no air flow through the split other than on in which the Fan is place.
- 23. • The highest pressure that booster Fan can produced without air reversal taking place is called as coactical pressure of the booster fan. • Critical pressure of a booster fan is the same ratio to the pressure of the main fan as the resistance of the split has no resistance of the trunk airways. • Pc = Pf x Rs /Rt • Where, Pc= Critical pressure of booster • • Pf= foressure of the surface fan • • Rs = Resistance of the split on which booster operates. • • Rt = Resistance of the trunk.
- 24. PURPOSE OF BOOSTER FAN • To increase on quantity of air in high resistancedistrict which are Located foot from the inbye. • For improving the working involvment in case of hot and deep mines through improve air velocity).
- 25. INSTALLATION OF BOOSTER FAN A booster fan is usually lighted / placed return airway to avoid the coal transport System which is usually in the the intake airway. The position of the booster fan in the return airway is chosen carefully. • * A neutral front at which is the poistion of the booster fan the pressure difference between the intake and return air way is equal to booster fan pressure
- 26. INSTALLATION OF BOOSTER FAN
- 27. 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
- 28. REFERENCE 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