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WorksheetsCâu hỏi trắc nghiệm về quạt gió
Total questions: 58
Worksheet time: 29mins
What is the form of ventilation with a fixed station on the surface, providing air through all the tunnels of the mine?
Main ventilation.
Area ventilation.
Local ventilation.
Mixed ventilation.
What is the form of ventilation using 1 to 2 mobile fans to ventilate a single tunnel or a working face?
Local ventilation.
Area ventilation.
Main ventilation.
Mixed ventilation.
According to the classification based on usage requirements in the tunnel, fans can be categorized into:
Fans for main ventilation, fans for local ventilation.
Centrifugal fans, axial fans.
Low pressure, medium pressure, high pressure.
Fans with large flow, medium flow, small flow.
What is the purpose of ventilation in underground mines?
To dilute the amount of explosive gas in the tunnel and reduce air temperature.
To provide oxygen for workers and reduce dust content in the air.
To dilute the amount of explosive gas in the tunnel and reduce dust content in the air.
To reduce air temperature, provide oxygen for workers, dilute and eliminate gases generated in the tunnel, especially methane.
The pressure difference between the two ends of a tunnel is called what?
Flow rate.
Pressure.
Productivity.
Static pressure.
The amount of air passing through the fan in a unit of time is called what?
Flow rate.
Pressure.
Productivity.
Static pressure.
When the angle of the guide blade changes, what happens?
The productivity and pressure of the fan will change.
The productivity of the fan will change.
The pressure of the fan will change.
The productivity and pressure of the fan do not change.
What is the diameter of the centrifugal fan blade ВЦД-32 М?
2500 mm
3200 mm
4500 mm
5200 mm
What is the productivity of the centrifugal fan ВЦД - 32M?
N= 200 ÷ 305m3/h.
N= 100 ÷ 200m3/h.
N= 478 ÷ 510m3/h.
N= 400 ÷ 478m3/h.
What is the pressure of the centrifugal fan ВЦД - 32M?
H= 478 ÷ 510kg/m2
H= 400 ÷ 478kg/m2
H= 200 ÷ 305kg/m2
H= 100 ÷ 200kg/m2
How many blades does the working wheel of the centrifugal fan ВЦД - 32M have?
56
30
36
60
In the structural diagram of the centrifugal fan ВЦД - 32M, positions 5, 7, 8 correspond to:
Guide part, spiral casing, electric motor.
Working wheel, shaft, shaft coupling.
Guide part, spiral casing, shaft coupling.
Working wheel, hub, electric motor.
In the structural diagram of the centrifugal fan ВЦД - 32M, positions 1, 3, 4 correspond to:
Working wheel, shaft, shaft coupling.
Guide part, spiral casing, mechanical part to rotate the blades.
Guide part, spiral casing, shaft, shaft coupling.
Working wheel, hub, mechanical part to rotate the blades.
When the centrifugal fan ВЦД - 32M operates, the working wheel rotates, and the air in the empty chambers between the blades leaves the center of the working wheel thanks to ...
centrifugal force
reaction force
gravity
axial force
To adjust the capacity and pressure in the centrifugal fan ВЦД - 32M, it is necessary to adjust ...
the angle of the guide blades
the voltage applied to the motor
the motor speed
the air duct
To lubricate the bearing of the shaft of the centrifugal fan ВЦД - 32M, use ...
heat-resistant grease I3
grease YC-2
oil CN-30,45,50
diesel oil
During operation, it is necessary to closely monitor the operation of the fan such as: The fan must not vibrate strongly, the noise must be smooth, the temperature of the shaft bearings must not exceed ... compared to the ambient temperature.
500 C
300 C
800 C
600 C
When the working wheel rotates, the air from both sides of the inlet is sucked in and pushed up along the ... to the outlet:
blade
straight
arc
spiral
The advantage of the centrifugal fan compared to the axial fan of the same power is:
large flow, low speed
medium flow, low noise, low speed
small flow, high noise, low speed
large flow, high noise, high speed
The axial fan YBT - 5.5 is used for:
ventilating a preparation tunnel, or a single-direction tunnel, or a shop tunnel where the main ventilation system cannot provide air
ventilating a preparation tunnel, or a single-direction tunnel
ventilating multiple preparation tunnels, or a single-direction tunnel, or a shop tunnel where the main ventilation system cannot provide air
ventilating multiple preparation tunnels, or two area tunnels, or a shop tunnel where the main ventilation system cannot provide air
In the structural diagram of the axial fan, positions 1,2,3,4 correspond to:
working wheel, blades, guide part, straightening part
front sliding surface, rear sliding surface, inlet, air duct
working wheel, blades, inlet, air duct
front sliding surface, rear sliding surface, guide part, straightening part
In the structural diagram of the axial fan, positions 5,6,7,8 correspond to:
front sliding surface, rear sliding surface, inlet, outlet
front sliding surface, rear sliding surface, inlet, air duct
working wheel, blades, inlet, air duct
front sliding surface, rear sliding surface, guide part, straightening part
The guide part placed in front of each working wheel in the axial fan has the effect of directing the airflow into the working wheel easily, ...
overcoming the vortex of the air, while adjusting the capacity and pressure of the fan
overcoming the vortex of the air, while adjusting the pressure
What is the purpose of the straightening device placed behind the impeller in axial fans?
To eliminate air vortexes and adjust the efficiency and pressure of the fan.
To eliminate air vortexes and adjust the pressure of the fan.
To adjust the efficiency and pressure of the fan.
To eliminate air vortexes.
What does the straightening device do in axial fans?
Directs air out of the fan to avoid energy loss.
Directs air into the fan to avoid energy loss.
Directs air out of the fan to conserve energy.
Directs air within the fan to avoid energy loss.
What is the aerodynamic shape of sliding surfaces in axial fans suitable for?
Allowing air to easily enter and exit the impeller while avoiding air vortexes and reducing energy loss.
Allowing air to easily enter the impeller while avoiding air vortexes and reducing energy loss.
Allowing air to easily exit the impeller while avoiding air vortexes and reducing energy loss.
Allowing the impeller to easily operate while avoiding air vortexes and reducing energy loss.
What is the typical positioning angle of the fixed blades in the guiding device of axial fans?
280.
200.
150.
250.
When the axial fan operates, how does the air leave the impeller?
By reaction.
By centrifugal force.
By gravity.
By axial force.
What is the capacity of the JBT - 5.5 axial fan?
N = 23 ÷ 194m3/s
N = 77 ÷ 410m3/s
N = 110 ÷ 230 m3/min
N = 400 ÷ 478m3/min
What is the power of the JBT - 5.5 axial fan?
P = 11kW
P = 5kW
P = 5.5kW
P = 15kW
When the axial fan operates, how does the air leave the impeller in relation to the fan axis?
Parallel
Perpendicular
At an angle of 30 degrees
At an angle of 45 degrees
What lubricant is used for the JBT - 5.5 axial fan?
YC-2 grease.
HD-40 oil.
I-13 heat-resistant grease.
L3 grease.
What is the advantage of axial fans compared to centrifugal fans of the same power?
Higher efficiency by 2 to 3%, higher air speed, compact size, lightweight.
Higher efficiency by 2 to 3%, average air speed, larger size, lightweight.
Higher efficiency by 1 to 2%, higher air speed, compact size, lightweight.
Higher efficiency by 2 to 3%, average air speed, compact size, lightweight.
What is used to transport axial fans from a flat surface to an inclined shaft?
Specialized lifting equipment.
Specialized transport gongs.
Pulley.
No equipment used.
To ensure safety, what must be fully equipped in the fan station besides protective devices?
Fire prevention equipment, lighting system, communication phone.
Protection system, explosion prevention equipment, lighting system.
Fire prevention equipment, lighting system.
What must the fan system have?
fire protection equipment, lighting system, communication phone.
protection system, explosion prevention equipment, lighting system.
fire protection equipment, protection system, lighting system.
protection system, backup duct, lighting system.
When the main fan stops and the backup fan is broken, what must be done immediately?
close the air door.
move the fan in to replace it.
cut off the power, hand over to the next shift.
open the air door for natural ventilation.
When the main fan is operating normally, when must the backup fan be allowed to operate?
when the air door is not tightly closed.
when the duct is torn.
when the explosive gas volume decreases.
when the methane gas content exceeds the allowable limit.
For a mine with explosive gas and dust, what is the minimum requirement for a backup fan motor?
at the nearest door.
at the nearest position on the surface.
right in the fan station.
at the main air door.
When wanting to stop or change the working mode of the fan, whose order must be followed?
the deputy shift manager.
the team leader.
the mine management board or the ventilation workshop manager.
the director.
According to safety regulations, the ground resistance of the fan and fan control equipment in the mine must meet the requirement:
≤ 1
≤ 2
≤ 3
≤ 4
According to safety regulations, the insulation resistance of the fan motor must ensure:
≥ 1 k/V.
≥ 2 k/V.
≥ 3 k/V.
≥ 4 k/V.
When operating the fan station, what must be done to reduce...
power when starting.
productivity when starting.
power when running at rated capacity.
fan pressure when starting.
When operating, the fan must be stopped immediately if there are signs of...
the motor making unusual noises, smoke, burning smell, or any part is overheating, the fan blades are bent, lack of oil.
the fan blades are bent.
the duct is slightly torn if it is a local fan.
lack of lubrication oil while the fan is working.
When the fan blades are rotating, the amount of air in front of the blades is pushed away, so the pressure at the blade area...
decreases, the amount of air behind flows into the area of reduced pressure.
increases, the amount of air behind flows into the area of reduced pressure.
decreases, the amount of air behind flows into the area of increased pressure.
increases, the amount of air behind flows into the area of increased pressure.
When must two fans be used in a joint operation?
using the corner ventilation method; many toxic gases appear; the resistance of the tunnel increases.
using the symmetrical ventilation method; toxic gases are released a lot; the resistance of the tunnel increases.
using the corner ventilation method; toxic gases are released a lot; the tunnel is getting larger.
using the mixed ventilation method; toxic gases are released a lot; the tunnel is getting deeper.
When changing the wind direction in the tunnel, what method is usually used?
by closing or opening the air ducts at the fan station.
by closing the air duct.
When changing the wind direction in the tunnel, what method is usually used?
Closing or opening the air ducts at the fan station.
Closing the suction air duct at the fan station.
Opening the blowing air duct at the fan station.
The rotation direction of the fan motor.
What is the maintenance time for the bearing of the centrifugal fan shaft?
6 months
3 months
4 months
5 months
Power supply for the fan, the motor does not rotate and makes a loud noise, the cause is due to ...
The motor is out of phase.
The fan blades are bent.
The motor is running in reverse.
Lack of lubricating oil.
When the fan or fan motor is working, it vibrates, the cause is due to ...
The electric motor is out of phase, some rotating parts are eccentric.
The working wheel is unbalanced, rotating eccentrically, the foundation bolts are loose.
The air duct is leaking, some rotating parts are eccentric, the foundation bolts are loose.
The fan blades are warped, the foundation bolts are loose.
What is the maintenance time for the bearing of the vertical fan shaft?
6 months
3 months
4 months
5 months
When using the suction ventilation method for the local fan, the end of the air duct must be at least ... from the furnace mirror.
L = 1.55 (m).
L = 5.5 (m).
L = 3 (m).
L = (3 ÷ 5) (m).
When using the blowing ventilation method for the local fan, the end of the air duct must be at least ... from the furnace mirror.
L = (3 ÷ 5) (m).
L = 5.5 (m).
L = 3 (m).
L = 1.55 (m).
The local fan must be placed in a clean air area, meaning it should be placed at least ... from the main tunnel door.
5m.
10m.
15m.
20m.
During operation, the temperature at the shaft bearings must not exceed ... compared to the ambient temperature.
50°C
40°C
60°C
70°C
The sequence of operating the vertical fan is:
Check closing the suction air duct, power on the motor, gradually open the air duct, monitor the working process, stop the fan.
Power on the motor, close the suction air duct, monitor the working process, gradually open the air duct, stop the fan.
Power on the motor, monitor the working process, close the suction air duct, stop the fan.
Close the suction air duct, monitor the working process, power on the motor, stop the fan.
When installing the air duct, in all cases, it is necessary to utilize air ducts with a long length and ...
appropriate diameter, few joints.
large diameter.
small diameter.
graded diameter.
