Learning Objective:
Recognize
the effects of foreign matter on
filtration in a hydraulic power
system
Recall the functions,
construction features, and
operating characteristic of
filters,
strainers,
and
dehydrators.
4-24.
A filter should be used to remove
large particles of foreign matter
from the fluid in a hydraulic
power system.
1.
True
2.
False
4-25.
To prevent the higher
differential pressure that is
generated at cold temperatures by
high fluid viscosity from causing
a false indication of a loaded
filter element, what device is
installed in the button-type
pressure differential indicator?
1.
Thermal lockout
2.
Viscosity sensor
3.
Collapsible filter element
4.
Pressure-operated bypass
valve
4-26.
Nonbypassing filters are used in
a hydraulic system to serve which
of the following functions?
1.
Decrease the frequency of
flushing the system
2.
Reduce the probability of the
failure of other system
components
3.
Reduce the circulation of
contaminated fluid in the
system
4.
All of the above
4-27.
How is the bypass valve, located
within the head assembly of some
filters, operated?
1.
Manually
2.
Pressure
3.
Electrically
4.
Magnetically
4-28.
When you find a filter
differential pressure indicator
button extended, what is the
first action you should take?
1.
Replace the indicator
2.
Replace the filter el
3.
Replace the filter assembly
4.
Verify that the releace of
the button is due to a loaded
filter element
4-29.
The recirculation of fluid
through a proportional-flow
filter over a period of time will
eventually accomplish the same
purpose as passage of the fluid
once through a full flow filter.
1.
True
2.
False
4-30.
The diameter, in microns, of the
largest spherical particle that
will pass through a filter under
a certain test condition defines
what filtration rating?
1.
Mean
2.
Nominal
3.
Absolute
4.
Adequate
4-31.
Which of the following types of
filter elements would most likely
be found in the air intake of a
compressor?
1.
Ceramic
2 .
Porous metal
3.
Woven screen wire
4.
Moving mechanical device
4-32.
Some pneumatic systems use
chemical driers to remove any
moisture that might collect in
the lines beyond the water
separators.
The driers remove
this moisture by what process?
1.
Absorption
2.
Condensation
3.
Evaporation
4.
Precipitation
4-33.
The chemical driers referred to
in the preceding question may be
identified by which of the
following terms?
1.
Air driers
2.
Desiccators
3.
Dehumidifiers
4.
Each of the above
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