Chapter 18

Question 1

Which compressor type requires the use of a shaft seal?
A. Hermetic
B. Semi-Hermetic
C. Serviceable
D. Open type

Answer 1

D

Question 2

Which of the following are designs of rotary compressors?
A. Helical Rotor
B. Stationary Single Blade
C. Rotating Vane
D. All of the above

Answer 2

D

Question 3

Packing gland seals are made of _____.
A. Metallic bellows soldered at one end to a ring bearing against a seal ring mounted on the shaft.
B. Metallic bellows soldered at one end to a ring bearing against a shoulder on the shaft.
C. Semi-metallic material impregnated with graphite.
D. A diaphragm soldered to a seal nose held between compressor body and cover plate.

Answer 3

C

Question 4

A two cylinder compressor has an 80mm(3.15in) bore and a stroke of 110mm(4.33in). What is the volume compressed per hour if the compressor operates at 800 r/min
A) 45.25 m3/h
B) 53.08 m3/h
C) 62.75 m3/h
D) 88.54 m3/h

Answer 4

B

Question 5

If the theoretical mass of refrigerant moved in a compressor is 9.72 kg per minute, and the compressor has a volumetric efficiency of 65%, what is the actual mass removed?
a. 6.32 kg per minute
b. 5.45 kg per minute
c. 11.25 kg per minute
d. 9.84 kg per minute

Answer 5

A

Question 6

If a compressor discharge pressure gauge indicates 960 kPa and the suction pressure is 130 kPa, what is the pressure ratio?
A. 3.84
B. 7.25
C. 4.59
D. 4.14

Answer 6

C