NCCER Millwright Level III: Module
15305 Mechanical Seals Exam with
Verified Detailed Answers
Barrier Fluid: -
correct answer ✅A fluid introduced under pressure into the
chamber between dual seals. It prevents The entry of process fluid
at a lower pressure and provides both cooling and lubrication to the
sealing faces.
Buffer fluid: -
correct answer ✅A fluid introduced at atmospheric pressure into
the chamber between dual seals. it provides both cooling and
lubrication to the sealing faces.
Cavitation: -
correct answer ✅The formation and eventual collapse of bubbles
in a fluid. Generally, its caused by the pumped liquid flashing to a
vapor as it enters the low-pressure area at the impeller inlet.
Concentric: -
correct answer ✅Describes two or more circles or arcs that share a
common center.
,NCCER Millwright Level III: Module
15305 Mechanical Seals Exam with
Verified Detailed Answers
Crazing: -
correct answer ✅The development of a network of tiny cracks in a
surface.
End Play: -
correct answer ✅Relative to pumps and similar equipment, the
amount of linear
(end to end) movement exhibited by a shaft.
Flashing: -
correct answer ✅The near instantaneous change of state from a
liquid to a vapor. Typically due to a pressure condition too low at
the current temperature to maintain the liquid state.
lapped: -
correct answer ✅Smoothed or polished.
Optical Flat: -
correct answer ✅A precisely lapped and polished piece of glass,
typically flat within a few millions of an inch, Its used with a light
source to analyze the flatness of other surfaces.
, NCCER Millwright Level III: Module
15305 Mechanical Seals Exam with
Verified Detailed Answers
Pipe strain: -
correct answer ✅Undesirable stress placed on pump structures
due to the poor alignment and/or insufficient support of connected
piping. Generally pumps should not be used as a point of support
for connected piping.
Shaft deflection: -
correct answer ✅Undesirable play in a shaft that allows movement
perpendicular to its length (Side to Side).
Shaft Runout: -
correct answer ✅Undesirable deviation in the surface of a shaft
from its centerline as it rotates.
TRADITIONAL shaft seals consist of? -
correct answer ✅Rope or braided packing wrapped around the
shaft and packed into a stuffing box. The series of packing rings is
then tightly compressed to prevent or limit leakage.
15305 Mechanical Seals Exam with
Verified Detailed Answers
Barrier Fluid: -
correct answer ✅A fluid introduced under pressure into the
chamber between dual seals. It prevents The entry of process fluid
at a lower pressure and provides both cooling and lubrication to the
sealing faces.
Buffer fluid: -
correct answer ✅A fluid introduced at atmospheric pressure into
the chamber between dual seals. it provides both cooling and
lubrication to the sealing faces.
Cavitation: -
correct answer ✅The formation and eventual collapse of bubbles
in a fluid. Generally, its caused by the pumped liquid flashing to a
vapor as it enters the low-pressure area at the impeller inlet.
Concentric: -
correct answer ✅Describes two or more circles or arcs that share a
common center.
,NCCER Millwright Level III: Module
15305 Mechanical Seals Exam with
Verified Detailed Answers
Crazing: -
correct answer ✅The development of a network of tiny cracks in a
surface.
End Play: -
correct answer ✅Relative to pumps and similar equipment, the
amount of linear
(end to end) movement exhibited by a shaft.
Flashing: -
correct answer ✅The near instantaneous change of state from a
liquid to a vapor. Typically due to a pressure condition too low at
the current temperature to maintain the liquid state.
lapped: -
correct answer ✅Smoothed or polished.
Optical Flat: -
correct answer ✅A precisely lapped and polished piece of glass,
typically flat within a few millions of an inch, Its used with a light
source to analyze the flatness of other surfaces.
, NCCER Millwright Level III: Module
15305 Mechanical Seals Exam with
Verified Detailed Answers
Pipe strain: -
correct answer ✅Undesirable stress placed on pump structures
due to the poor alignment and/or insufficient support of connected
piping. Generally pumps should not be used as a point of support
for connected piping.
Shaft deflection: -
correct answer ✅Undesirable play in a shaft that allows movement
perpendicular to its length (Side to Side).
Shaft Runout: -
correct answer ✅Undesirable deviation in the surface of a shaft
from its centerline as it rotates.
TRADITIONAL shaft seals consist of? -
correct answer ✅Rope or braided packing wrapped around the
shaft and packed into a stuffing box. The series of packing rings is
then tightly compressed to prevent or limit leakage.
