2025 STATIONARY ENGINEERING EXAM COMPREHENSIVE QUESTIONS AND VERIFIED ANSWERS 2025/2026
Drums internals comprise all apparatus with in a drum, including all baffles that quiet
or separate the steam and water, the various devices that may be used for affecting
What are drum internals? the separation of the steam and water, and the various chemical and feed water
admissions piping and blow down lines
They remove the entrained moisture in the steam. The scrubber is not highly
effective in removing small amounts of fine steam mist, but it suffices to eliminate
most of the usual spray and splatter as well as to break up and eliminate any dry
foam
What do scrubbers remove? After passing through a washer, the moisture droplets in the steam are enlarged.
This increases the effectiveness of the scrubber and helps reduce the carry-over.
The steam passed between closely fitted corrugated plates or screens on which the
mists are deposited in an action comparable to filtration. The velocity is low to avoid
re-entrainment. The collected water is dripped by gravity to the boiler water below.
The efficiency of the scrubber depends upon the following variables.
a. Surface area
Explain how a scrubber works? b. Low steam velocity
c. Steam passage irregularities
d. Time of contact
Bare-Plate Walls- All internally fired, portable or integral fire box boilers, such as
scotch marine or locomotive boilers.
Bare-Tube Wall- They may be constructed of plain tubes, fin tubes or studded tubes,
with a firebrick or refractory backing.
Covered-Tubed Walls- Consist of tubes protected either by integral blocks or
attached blocks. Blocks may be integral blocks of metal or attached blocks of metal,
refractory or metal-enclosed refractory.
Name different types of water walls
The purpose of the protection is to eliminate erosion and corrosion by the
combustion products of waste heat, assist combustion, prevent escape of molten
slag and provide a chill for a moving fuel bed
Blow-off connections are provided in each of the lower water wall headers for the
removal of sludge. Care must be taken in making use of these blow downs. To avoid
What types of valves are found on a water upsetting the circulation of water in the water wall, the water wall should never be
wall header? blown down while the boiler is steaming.
Forced circulation is what makes controlled circulation possible. In the C & E design
it involves the use of a pump or pumps to force water through all the steam-
What is a forced circulation boiler? generating circuits. Thus insuring a positive flow in one direction at all times,
regardless of the rate of heat application.
Two flat plates, the tube sheet and the handhole are flanged over. These are either
joined together or joined to a wrapper sheet, by riveting. The flat surfaces are stayed
by hollow steel stay bolts, screwed into each sheet and then riveted over against the
Describe a box header sheet. The tubes are fastened to the tube sheet by being expanded in the tube holes
and then are flared slightly to increase the holding power.
Water tubes, firebrick, block-refractory face, cast iron, steel or ally steel.
Insulating block, expanded metal, insulating cement, plastic and ceramic
What material is used to build a furnace refractories.
wall?
Insulation such as mineral wool and a steel exterior casing.
Drums internals comprise all apparatus with in a drum, including all baffles that quiet
or separate the steam and water, the various devices that may be used for affecting
What are drum internals? the separation of the steam and water, and the various chemical and feed water
admissions piping and blow down lines
They remove the entrained moisture in the steam. The scrubber is not highly
effective in removing small amounts of fine steam mist, but it suffices to eliminate
most of the usual spray and splatter as well as to break up and eliminate any dry
foam
What do scrubbers remove? After passing through a washer, the moisture droplets in the steam are enlarged.
This increases the effectiveness of the scrubber and helps reduce the carry-over.
The steam passed between closely fitted corrugated plates or screens on which the
mists are deposited in an action comparable to filtration. The velocity is low to avoid
re-entrainment. The collected water is dripped by gravity to the boiler water below.
The efficiency of the scrubber depends upon the following variables.
a. Surface area
Explain how a scrubber works? b. Low steam velocity
c. Steam passage irregularities
d. Time of contact
Bare-Plate Walls- All internally fired, portable or integral fire box boilers, such as
scotch marine or locomotive boilers.
Bare-Tube Wall- They may be constructed of plain tubes, fin tubes or studded tubes,
with a firebrick or refractory backing.
Covered-Tubed Walls- Consist of tubes protected either by integral blocks or
attached blocks. Blocks may be integral blocks of metal or attached blocks of metal,
refractory or metal-enclosed refractory.
Name different types of water walls
The purpose of the protection is to eliminate erosion and corrosion by the
combustion products of waste heat, assist combustion, prevent escape of molten
slag and provide a chill for a moving fuel bed
Blow-off connections are provided in each of the lower water wall headers for the
removal of sludge. Care must be taken in making use of these blow downs. To avoid
What types of valves are found on a water upsetting the circulation of water in the water wall, the water wall should never be
wall header? blown down while the boiler is steaming.
Forced circulation is what makes controlled circulation possible. In the C & E design
it involves the use of a pump or pumps to force water through all the steam-
What is a forced circulation boiler? generating circuits. Thus insuring a positive flow in one direction at all times,
regardless of the rate of heat application.
Two flat plates, the tube sheet and the handhole are flanged over. These are either
joined together or joined to a wrapper sheet, by riveting. The flat surfaces are stayed
by hollow steel stay bolts, screwed into each sheet and then riveted over against the
Describe a box header sheet. The tubes are fastened to the tube sheet by being expanded in the tube holes
and then are flared slightly to increase the holding power.
Water tubes, firebrick, block-refractory face, cast iron, steel or ally steel.
Insulating block, expanded metal, insulating cement, plastic and ceramic
What material is used to build a furnace refractories.
wall?
Insulation such as mineral wool and a steel exterior casing.
