FINAL EXAM Flashcards
a requirement for supporting human life, but the beneficial physiological and psychological side effects enhance employee safety, comfort, health, and morale.
Ventilation
provide a quality of mine air to ensure the health & safety of the mine workers as well as providing a suitable atmosphere for the safe and effective operation of the mine.
Mine Ventilation
a method by which air from the atmosphere is used to ventilate the mine.
Natural Ventilation
uses fan system to draw air from the main current and force it through canvass or galvanized
iron pipe to a point near the face of mine workings.
Mechanical Ventilation
are mechanical devices which convert mechanical energy to fluid energy.
Mine Fans
have radial blades and the blades maybe curved either forward or backward.
Centrifugal Fan
consist of a single propeller-type of fan (w/ seven or more blades).
Axial Fan
are the principal fans used to produce the general ventilation air current in the mine.
Main Fans
are usually of small size, portable and temporarily installed to ventilate working places through which the general ventilating air may not otherwise pass (dead-end openings).
Auxiliary Fans
are used extensively in metal mines. They are applied to a fan that handles the entire flow in an airway and thus serves to increase the quantity of air in circulation.
Booster Fans
applies to natural ventilation system where the fan is placed at the top of return (ventilation) shaft.
The pressure in the mine is below atmospheric level.
Exhaust Fans
fan placed at the top of the intake shaft where the pressure in the mine is above atmospheric level.
Blowing Fans
In the ________, the fan inlet is open to the atmosphere and the fan outlet to the mine intake shaft.
Forcing System
In an ________, the fan inlet is open to the mine through the return shaft and the fan is open to the atmosphere usually through an “EVASE” The top of the return shaft has a weak wall or an airlock.
Exhausting System
_________ is an expanding chimney of an exhaust fan that has the function of converting kinetic energy of the air as it leaves the fan into potential or pressure energy before the air escapes into the atmosphere.
Fan Evase
air bridges that allow the intake and return airways to cross one another without mixing. It is properly built with high-quality materials.
Air Crossing
are physical barriers erected between the intake and return airways to prevent the air flowing in them from mixing with each other.
Stoppings
simply hinged or movable partition within a stopping designed to permit passage of men & equipment.
Doors
are used to control and redistribute the quantity of flow in each split of air
Regulators
Enumerate the Ventilation Controls
- Stoppings
- Doors
- Air Crossings
- Regulators
- Vent tubes, Curtain and Line Brattice
True or False. Air always flow from a point with higher total head to a point with lower total head.
True
True or False. Mine Fans provide speed to overcome the resistance to flow.
False
True or False. The pressure gradient for a booster system is a combination of the gradients of the exhausting and forcing systems.
True
True or False. Dust consist of minute particles of gases affecting lungs.
False
Exhausting fans are preferred to coal mine ventilation.
True
What are the 5 measures to determine fan performance?
- the noise characteristics
- the power requirements
- the efficiency of the fans
- the case of changing operating points
- the range of head and quantity delivered
[SOLVING] What is the velocity in an entry 10 feet high and 22 feet wide, with a quantity of 11,380 CFM?
51.73 fpm
[SOLVING] The quantity of return air was 14,500 cfm and found to contain 3.4 % CH4. What is the total volume needed to reduce the methane content to 2.0 %.
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