Air Compression

Question 1

Which of the following types of air compressors requires internal lubrication?

A) Rotary lobe
B) None of the above
C) Axial
D) Centrifugal
E) Rotary screw

Answer 1

B) None of the above

Question 2

Compressor lubrication oil provides:

1. Corrosion resistance
2. Sealing around pistons, vanes, etc
3. Heat removal
4. Wear prevention

A) 1, 2, 4
B) 2, 4
C) 1, 2, 3, 4
D) 1, 3, 4
E) 2, 3, 4

Answer 2

C) 1, 2, 3, 4

Question 3

The compressor that would favour volume over pressure would be the:

A) Sliding vane
B) Rotary lobe
C) Axial
D) Screw
E) Centrifugal

Answer 3

E) Centrifugal

Question 4

Which of the following is not a true advantage of sliding vane compressors over reciprocating compressors?

A) They produce a steadier flow of air
B) They require less power when staring up
C) Their initial cost is less
D) They do not require inlet or discharge valves
E) They are more efficient

Answer 4

E) They are more efficient

Question 5

Compressor internal lubrication applies lubrication to:

A) Crankshaft bearings
B) Pistons and cylinder walls
C) Rotor shaft bearings
D) Connecting rod bearings
E) Crossheads

Answer 5

B) Pistons and cylinder walls

Question 6

An advantage of dynamic compressors is that they do not require:

A) Inlet baffles
B) Internal lubrication
C) External lubrication
D) Maintenance
E) Air receivers

Answer 6

B) Internal lubrication

Question 7

To reduce air temperature between stages, we would use:

A) An intercooler
B) An aftercooler
C) A chiller
D) A convertor
E) A receiver

Answer 7

A) An intercooler

Question 8

In a centrifugal compressor, the kinetic energy is converted to potential energy in the:

A) Intercooler
B) Volute only
C) Compressor cavity
D) Volute, diffuser or both
E) Diffuser only

Answer 8

D) Volute, diffuser or both

Question 9

A constant speed compressor is controlled by a/an:

A) Fluid coupling
B) Unloader
C) VFD (Variable Frequency Drive)
D) Variac (variable autotransformer)
E) Variable speed coupling

Answer 9

B) Unloader

Question 10

A reciprocating compressor unloader:

A) Throttles discharge
B) Uses variable inlet vanes
C) Uses a wastegate
D) Throttles suction
E) Holds intake valves open

Answer 10

E) Holds intake valves open