3rd stationary engineer A B Test questions and
answers with solutions
AB 6. 3 types of heat transfer - ANSWER Radiant heat - Transmitted from
hot body to a cold body by means of direct radiation
Co
A 7. What is a combustion chamber? - ANSWER The area of the boiler
where the complete burning of fuel occurs.
B 8. What is an internally fired boiler and 4 types - ANSWER Internally
fired boilers have the grates and combustion chamber enclosed within
the boiler shell.
Scotch Marine
Vertical Fire Tube
Locomotive
Cast Iron Package
B 13. Name 2 ways to support and take care of expansion in a HRT boiler.
Which way is best? - ANSWER It can be set on saddles equipped with
rollers to permit movement of the boiler as it expands and contracts. It
may also be suspended from hangers and supported by overhead beams.
Hanging by beams is best, puts no hardship on furnace walls.
,B 14. What is a longitudinal Joint?
What is a circumfermential joint? - ANSWER A longitudinal joint is a
seam running the length of the shell and it is butt strapped or fusion
welded. It is above the fire line to avoid overheating.
Lap joint running the circumference of the drum.
B 17.Describe a scotch marine boiler and how its fired - ANSWER It is an
internally fired self contained horizontal return fire boiler. It is a
cylindrical shell containing the combustion chamber and tubes that are
surrounded by water.
B 19. Describe the circulation of water within a Stirling boiler. - ANSWER
feed water enters the top rear drum, passes down the rear tubes to the
mud drum. steam and boiler water go up the front and center tubes to
the front and center drums. CIRCULATING TUBES allow boiler water to
pass between the drums. what does not go out as steam, goes back
down the rear tubes.
B 23. What type of stays are used in a wet back scotch marine boiler. -
ANSWER Stay bolts and through stays. These sometimes will have a
telltale drilled in them.
B 25. What is a super heater? What are the advantages? - ANSWER A
bank of tubes through which only steam passes through without raising
pressure.
,Advantages: increased efficiency of boilers, delivering drier steam. Drier
steam can be transmitted long distances with minimal heat loss. With
drier steam condensation and corrosion are reduced.
B 27. What is an economize? What is an air preheater? - ANSWER
Economizer: heat exchanger located in the breaching between the boiler
and stack designed to recover waste heat from the products of
combustion by preheating the feedwater
Air preheater: consists of a series of tubes or plates that have hot gases
on one side and incoming air on the other. heat in the hot gasses leaving
the boiler is recovered by the incoming air.
both reduce stack temperatures and increase boiler efficiency
B 30. Cross section of a 1" bolt - ANSWER D x D x .7854
1 x 1 x .7854 = .7854sq"
B 33. What is meant by "factor of safety" - ANSWER The comparison of
the tensile strength to the actual working stress or the bursting pressure
divided by the working pressure.
B 34. What is the factor of safety for boilers, flywheels, and pipes? -
ANSWER New Boiler 4
Preowned constructed to ASME standards 5
Flywheel 3
Pipe 8
, B 35. What is a lap joint? What is a butt joint? What is a butt strap joint?
- ANSWER LAP JOINT = when one plate overlaps the other and is joined
-----
BUTT JOINT = when two ends of the plate meet end to end and are
joined
-----
BUTT-STRAP JOINT = when two ends of the plate meet end to end and
are joined by a plate. (one plate is a single butt strap joint / two plates
are a double butt strap joint)
B 39. What type of stays are used in the heads of water tub boilers and
why? - ANSWER There are no stays. The head of the boiler drum is
shaped with a die, which dishes and forms them into the shape they
would take as a result of the pressure to which they will be subjected to.
A 40. Why is a row of tubes sometimes left out of an HRT boiler? -
ANSWER To improve carryover which will reduce carryover
AB 41. In a fire tube boiler how are tubes secured in a tube sheet and
why? In a water tube? In a water tube boiler why are only some tube
ends beaded? - ANSWER Fire tube boiler tubes are rolled and beaded to
prevent heat damage, and to keep them from pulling out.
Water tube boilers are rolled then flared to keep them from pulling out.
Also for drainage in the upper drum and prevent air pockets in the lower
drum.
answers with solutions
AB 6. 3 types of heat transfer - ANSWER Radiant heat - Transmitted from
hot body to a cold body by means of direct radiation
Co
A 7. What is a combustion chamber? - ANSWER The area of the boiler
where the complete burning of fuel occurs.
B 8. What is an internally fired boiler and 4 types - ANSWER Internally
fired boilers have the grates and combustion chamber enclosed within
the boiler shell.
Scotch Marine
Vertical Fire Tube
Locomotive
Cast Iron Package
B 13. Name 2 ways to support and take care of expansion in a HRT boiler.
Which way is best? - ANSWER It can be set on saddles equipped with
rollers to permit movement of the boiler as it expands and contracts. It
may also be suspended from hangers and supported by overhead beams.
Hanging by beams is best, puts no hardship on furnace walls.
,B 14. What is a longitudinal Joint?
What is a circumfermential joint? - ANSWER A longitudinal joint is a
seam running the length of the shell and it is butt strapped or fusion
welded. It is above the fire line to avoid overheating.
Lap joint running the circumference of the drum.
B 17.Describe a scotch marine boiler and how its fired - ANSWER It is an
internally fired self contained horizontal return fire boiler. It is a
cylindrical shell containing the combustion chamber and tubes that are
surrounded by water.
B 19. Describe the circulation of water within a Stirling boiler. - ANSWER
feed water enters the top rear drum, passes down the rear tubes to the
mud drum. steam and boiler water go up the front and center tubes to
the front and center drums. CIRCULATING TUBES allow boiler water to
pass between the drums. what does not go out as steam, goes back
down the rear tubes.
B 23. What type of stays are used in a wet back scotch marine boiler. -
ANSWER Stay bolts and through stays. These sometimes will have a
telltale drilled in them.
B 25. What is a super heater? What are the advantages? - ANSWER A
bank of tubes through which only steam passes through without raising
pressure.
,Advantages: increased efficiency of boilers, delivering drier steam. Drier
steam can be transmitted long distances with minimal heat loss. With
drier steam condensation and corrosion are reduced.
B 27. What is an economize? What is an air preheater? - ANSWER
Economizer: heat exchanger located in the breaching between the boiler
and stack designed to recover waste heat from the products of
combustion by preheating the feedwater
Air preheater: consists of a series of tubes or plates that have hot gases
on one side and incoming air on the other. heat in the hot gasses leaving
the boiler is recovered by the incoming air.
both reduce stack temperatures and increase boiler efficiency
B 30. Cross section of a 1" bolt - ANSWER D x D x .7854
1 x 1 x .7854 = .7854sq"
B 33. What is meant by "factor of safety" - ANSWER The comparison of
the tensile strength to the actual working stress or the bursting pressure
divided by the working pressure.
B 34. What is the factor of safety for boilers, flywheels, and pipes? -
ANSWER New Boiler 4
Preowned constructed to ASME standards 5
Flywheel 3
Pipe 8
, B 35. What is a lap joint? What is a butt joint? What is a butt strap joint?
- ANSWER LAP JOINT = when one plate overlaps the other and is joined
-----
BUTT JOINT = when two ends of the plate meet end to end and are
joined
-----
BUTT-STRAP JOINT = when two ends of the plate meet end to end and
are joined by a plate. (one plate is a single butt strap joint / two plates
are a double butt strap joint)
B 39. What type of stays are used in the heads of water tub boilers and
why? - ANSWER There are no stays. The head of the boiler drum is
shaped with a die, which dishes and forms them into the shape they
would take as a result of the pressure to which they will be subjected to.
A 40. Why is a row of tubes sometimes left out of an HRT boiler? -
ANSWER To improve carryover which will reduce carryover
AB 41. In a fire tube boiler how are tubes secured in a tube sheet and
why? In a water tube? In a water tube boiler why are only some tube
ends beaded? - ANSWER Fire tube boiler tubes are rolled and beaded to
prevent heat damage, and to keep them from pulling out.
Water tube boilers are rolled then flared to keep them from pulling out.
Also for drainage in the upper drum and prevent air pockets in the lower
drum.
