A compressor seal is required to prevent:

A compressor seal is required to prevent:

a. Refrigerant and oil leakage into the compressor
b. Refrigerant and oil leakage along the shaft
c. Prevent moisture from escaping the compressor
d. Prevent dirt and moisture from leaving the compressor






Answer: B

The function of a safety heads is to:

The function of a safety heads is to:

a. Relieve the pressure of compression when the compressor cycles off
b. Relieve the pressure in the cylinder if a liquid slug of refrigerant is in the cylinder
c. Protect the compressor from over heating
d. Protect the compressor from short cycling

Answer: B

Which part is not a part of a reciprocating compressor?

Which part is not a part of a reciprocating compressor?

a. Inlet vane
b. Crankshaft
c. Connecting rod
d. Piston








Answer: A

Consider a single stage, single acting reciprocating compressor. Calculate the piston displacement in cubic metres per minute, if given the following: piston stroke 12 cm piston diameter 10 cm piston speed 1100 working strokes per minute

Consider a single stage, single acting reciprocating compressor.
Calculate the piston displacement in cubic metres per minute, if given the following:
piston stroke 12 cm
piston diameter 10 cm
piston speed 1100 working strokes per minute

a. 1.031
b. 1.033
c. 1.035
d. 1.037
e. 1.039








Answer: D

Which one is NOT true about rotating mechanical seals

Which one is NOT true about rotating mechanical seals

a. Low cost
b. Less maintenance
c. Reduced wear on rotating shafts
d. Leakage is reduced to a minimum







Answer: A

Packing gland seals are used on what compressor?

Packing gland seals are used on what compressor?

a. Open type
b. Hermetic type
c. Large capacity ammonia compressor
d. Rotating sliding vane design
e. Helical rotor design







Answer: C

Shaft seals are used on what compressor?

Shaft seals are used on what compressor?

a. Open type
b. Hermetic type
c. Stationary single-blade design
d. Rotating sliding vane design
e. Helical rotor design








Answer: A

Advantages of the centrifugal compressor are?

Advantages of the centrifugal compressor are?

a. No moving parts
b. Can be coupled to an electric motor
c. Cheap
d. A and B
e. All of the above







Answer: D

Helical rotors revolve at speeds up to ___ r/min

Helical rotors revolve at speeds up to ___ r/min

a. 1550
b. 2550
c. 3550
d. 4550
e. 5550







Answer: C

Rotary compressor types are?
i. Open type
ii. Hermetic type
iii. Stationary single-blade design
iv. Rotating sliding vane design
v. Helical rotor design

a. iii, iv,v
b. i, ii, iii
c. ii, iv, v
d. i, iii, iv
e. ii, iii, iv






Answer: A

Reciprocating Compressor Types are? i. Open type ii. Hermetic type iii. Semihermetic type iv. Rotating sliding vane design v. Helical rotor design

Reciprocating Compressor Types are?
i. Open type
ii. Hermetic type
iii. Semihermetic type
iv. Rotating sliding vane design
v. Helical rotor design

a. i, ii, iv
b. ii, iii, v
c. i, ii, iii
d. iii, iv, v
e. i, iii, v







Answer: C

Which of the following compressor types uses impellers to draw in vapour?

Which of the following compressor types uses impellers to draw in vapour?

a) Centrifugal compressors
b) Rotary compressors
c) Reciprocating Compressors
d) None of the above
e) All of the above







Answer: A

In a refrigeration system, the purpose of the compressor is to

In a refrigeration system, the purpose of the compressor is to

a) establish two pressure levels
b) reject the heat from the system
c) absorb the heat into the system
d) regulate the flow of the refrigerant
e) heat the refrigerant








Answer: A

Which of the following is the compressor responsible for doing? i) Maintains a high pressure in the condenser ii) Maintains a low pressure in the evaporator iii) Raises the pressure of the refrigerant

Which of the following is the compressor responsible for doing?
i) Maintains a high pressure in the condenser
ii) Maintains a low pressure in the evaporator
iii) Raises the pressure of the refrigerant

a) i only
b) both i and iii
c) both ii and iii
d) iii only
e) i, ii, and iii








Answer: E

Which of the following is not a function of the compressor in a refrigeration system?

Which of the following is not a function of the compressor in a refrigeration system?

a) draw low pressure refrigerant out of the evaporator
b) draw low temperature refrigerant out of the evaporator
c) lower the temperature of the refrigerant
d) maintain sufficiently low pressure in the evaporator
e) raise the pressure of the refrigerant








Answer: C

The pressure ratio of a refrigeration compressor can be calculated by dividing the:

The pressure ratio of a refrigeration compressor can be calculated by dividing the:

a. Discharge gage pressure by the inlet gage pressure
b. Swept volume of a cylinder by its clearance volume
c. Absolute inlet pressure by the absolute discharge pressure
d. Absolute discharge pressure by the absolute inlet pressure, and then multiplying by the number of cylinders
e. Absolute discharge pressure by the absolute inlet pressure







Answer: E

Refrigerant compressors:

Refrigerant compressors:

a. Must have intercoolers
b. Could be centrifugal type
c. Use automotive-style suction and discharge valves
d. Have more cooling fins than air compressors
e. Discharge directly into the evaporator







Answer: B

In a sliding vane design refrigeration compressor, a good seal is maintained between the vanes and the cylinder by:

In a sliding vane design refrigeration compressor, a good seal is maintained between the vanes and the cylinder by:

a. Centrifugal force
b. Lube oil
c. High pressure refrigerant vapour
d. Liquid refrigerant carryover
e. The eccentric rotor size

Answer: A

Which of the following is NOT a function of the refrigeration compressor?

Which of the following is NOT a function of the refrigeration compressor?

a. Raises the pressure of the refrigerant
b. Raises the temperature of the refrigerant
c. Maintains a low pressure in the evaporator
d. Circulates refrigerant through the system
e. Removes energy from the vapour







Answer: E

A stationary crankshaft seal used on refrigeration compressors, which consists of a metallic bellows soldered at one end to a ring, and which presses against a shoulder on the shaft is called a:

A stationary crankshaft seal used on refrigeration compressors, which consists of a metallic bellows soldered at one end to a ring, and which presses against a shoulder on the shaft is called a:

a. Packing gland seal
b. Diaphragm seal
c. Bellows seal
d. Rotating Mechanical seal
e. Set screw







Answer: C