Book 2: 6-27 - "Air Compression" Flashcards
A rotary lobe compressor has _____ within a casing.
Select one:
A. Two figure-eight shaped impellers revolving in the same direction
B. Two figure-eight shaped impellers revolving in opposite directions
C. Two figure-six shaped impellers revolving in opposite directions
D. One figure-eight shaped impeller
E. Two figure-six shaped impellers revolving in the same direction
B. Two figure-eight shaped impellers revolving in opposite directions
The temperature very exceptional circumstances may be about _____ near the end of the compression stroke.
Select one:
A. 150°C (302°F)
B. 175°C (347°F)
C. 90°C (194°F)
D. 225°C (437°F)
E. 75°C (167°F)
D. 225°C (437°F)
One of the categories of air compressors is the _____ type.
Select one:
A. Reciprocating
B. Positive displacement
C. Rotary screw
D. Centrifugal
E. Rotary lobe
B. Positive displacement
A disadvantage of the rotary screw compressor is:
Select one:
A. They can be classed as “oil-free” if so designed
B. Vibration free operation
C. Smooth air flow
D. No suction or discharge valves are required
E. It is less efficient than a reciprocating type
E. It is less efficient than a reciprocating type
The crosshead in a double-acting compressor serves as a bearing and is the point where:
Select one:
A. Linear motion stops
B. All motion stops
C. Circular motion stops
D. Circular motion becomes linear motion
E. Circular motion becomes angular motion
D. Circular motion becomes linear motion
Some uses of compressed air in buildings include all of the following except:
Select one:
A. Extinguishing fires in buildings.
B. Mixing or agitating in water treatment processes
C. Atomizing fuel oil
D. Operating building environmental control systems
E. Starting engines
A. Extinguishing fires in buildings.
Generally, positive displacement compressors favor:
Select one:
A. Pressure
B. Speed
C. Time
D. Volume
E. Temperature
A. Pressure
Lubricating oil is necessary in an air compressor to perform the following functions except:
Select one:
A. To reduce friction
B. To provide seating
C. To prevent wear
D. To reduce corrosion
E. To remove heat
B. To provide seating
A piston rod in a double-acting compressor has:
Select one:
A. Linear travel at one end and angular at the other
B. Linear travel at both ends
C. Angular travel at one end only
D. Linear travel at one end only
E. Angular travel at both ends
B. Linear travel at both ends
One of the categories of air compressors is the _____ type.
Select one:
A. Rotary lobe
B. Dynamic
C. Centrifugal
D. Reciprocating
E. Rotary screw
B. Dynamic
One of the disadvantages of using compressed air to drive tools and other machinery over the use of electricity or steam is:
Select one:
A. Compressed air machines cannot be damaged by overloading
B. Air driven hand tools do not become hot after extensive use
C. Air driven hand tools do not create a shock hazard
D. Compressed air tools are that they are usually more expensive
E. Air driven hand tools are lighter in weight
D. Compressed air tools are that they are usually more expensive
External lubrication of the compressor refers to lubrication of all of the following except the:
Select one:
A. Crankshaft bearings
B. Rotor shaft bearings on rotary and dynamic compressors
C. Cylinder walls
D. Connecting rod bearings
E. Crossheads on reciprocating compressors
C. Cylinder walls
Generally, dynamic compressors favor:
Select one:
A. Time
B. Speed
C. Temperature
D. Volume
E. Pressure
D. Volume
Which of the following statements about centrifugal compressor advantages is incorrect?
Select one:
A. They are commonly used for large volume applications
B. They are commonly used for low-pressure applications
C. They are of simple and rugged construction
D. They have low maintenance requirements
E. Their efficiency is higher than the positive displacement type
E. Their efficiency is higher than the positive displacement type
Internal lubrication of the compressor refers to lubrication of all of the following except the:
Select one:
A. Crankshaft bearings
B. Casings of the applicable compressor
C. Pistons
D. Cylinder walls
E. Vanes
A. Crankshaft bearings
