4B POWER ENGINEERING CERTIFICATION
EVALUATION QUESTIONS AND SOLUTIONS
STUDY GUIDE
●● Large journal or sleeve bearings have grooves:
A) In the high pressure area of the bearing babbit
B) Cut into the bearing housing
C) For distributing lubricant evenly just after the pressure area
D) In the non-pressure area
Answer: D) In the non-pressure area
●● The weight of one liter of water at 4°C is ___________ N.
A) 1.89
B) 8.91
C) 9.18
D) 9.81
Answer: D) 9.81
●● ________________ is the head developed by a centrifugal pump
when running with its discharge valve closed.
A) Total dynamic head
B) Velocity head
,C) Total static head
D) Shut off Head
Answer: D) Shut off Head
●● Wear rings in centrifugal pumps:
A) Separate the suction and discharge
B) Are installed on impellers
C) Protect the shaft from wear
D) both a and d
Answer: B) Are installed on impellers
●● Compression type packing:
A) May be saturated with a lubricating material
B) Reduces the maintenance cost on the pump
C) Protects the shaft from scoring and corrosion
D) Is used with all mechanical seals
Answer: A) May be saturated with a lubricating material
●● Wear rings are usually constructed of:
A) Ceramics or aluminum
B) Graphite or bronze
C) Bronze or cast iron
,D) Steel or alloy steel
Answer: C) Bronze or cast iron
●● The main advantage of a pump using a mechanical seal is:
A) Lower first cost
B) Less maintenance
C) Less lubrication
D) Ease of repair
Answer: B) Less maintenance
●● What size of packing would you use to repack a pump gland having
a stuffing box bore of 8.6 cm and a pump shaft diameter of 6.7 cm?
A) 0.5 cm
B) 1.6 cm
C) 0.675 cm
D) 0.95 cm
Answer: D) 0.95 cm
●● A speed-increasing gear is commonly used on:
A) Rotary lobe compressors
B) Screw compressors
C) Sliding vane compressors
, D) Reciprocating compressors
Answer: B) Screw compressors
●● Centrifugal compressors:
A) Are used for high pressure and low flow
B) Could be of the multi-stage type
C) Must have intercoolers when multi-staged
D) Must have a safety valve on the discharge when steam driven
Answer: B) Could be of the multi-stage type
●● Air compressor intercoolers are installed ____________.
A) before each stage
B) after each stage
C) before and after each stages
D) between each stage
Answer: D) between each stage
●● When is a stop valve allowed on the outlet of a safety valve?
A) on low pressure boilers only
B) if there is more than one safety valve
C) if a rupture disc is placed between the stop valve and the safety valve
D) never allow a valve at the outlet
EVALUATION QUESTIONS AND SOLUTIONS
STUDY GUIDE
●● Large journal or sleeve bearings have grooves:
A) In the high pressure area of the bearing babbit
B) Cut into the bearing housing
C) For distributing lubricant evenly just after the pressure area
D) In the non-pressure area
Answer: D) In the non-pressure area
●● The weight of one liter of water at 4°C is ___________ N.
A) 1.89
B) 8.91
C) 9.18
D) 9.81
Answer: D) 9.81
●● ________________ is the head developed by a centrifugal pump
when running with its discharge valve closed.
A) Total dynamic head
B) Velocity head
,C) Total static head
D) Shut off Head
Answer: D) Shut off Head
●● Wear rings in centrifugal pumps:
A) Separate the suction and discharge
B) Are installed on impellers
C) Protect the shaft from wear
D) both a and d
Answer: B) Are installed on impellers
●● Compression type packing:
A) May be saturated with a lubricating material
B) Reduces the maintenance cost on the pump
C) Protects the shaft from scoring and corrosion
D) Is used with all mechanical seals
Answer: A) May be saturated with a lubricating material
●● Wear rings are usually constructed of:
A) Ceramics or aluminum
B) Graphite or bronze
C) Bronze or cast iron
,D) Steel or alloy steel
Answer: C) Bronze or cast iron
●● The main advantage of a pump using a mechanical seal is:
A) Lower first cost
B) Less maintenance
C) Less lubrication
D) Ease of repair
Answer: B) Less maintenance
●● What size of packing would you use to repack a pump gland having
a stuffing box bore of 8.6 cm and a pump shaft diameter of 6.7 cm?
A) 0.5 cm
B) 1.6 cm
C) 0.675 cm
D) 0.95 cm
Answer: D) 0.95 cm
●● A speed-increasing gear is commonly used on:
A) Rotary lobe compressors
B) Screw compressors
C) Sliding vane compressors
, D) Reciprocating compressors
Answer: B) Screw compressors
●● Centrifugal compressors:
A) Are used for high pressure and low flow
B) Could be of the multi-stage type
C) Must have intercoolers when multi-staged
D) Must have a safety valve on the discharge when steam driven
Answer: B) Could be of the multi-stage type
●● Air compressor intercoolers are installed ____________.
A) before each stage
B) after each stage
C) before and after each stages
D) between each stage
Answer: D) between each stage
●● When is a stop valve allowed on the outlet of a safety valve?
A) on low pressure boilers only
B) if there is more than one safety valve
C) if a rupture disc is placed between the stop valve and the safety valve
D) never allow a valve at the outlet
