Page 33 - Parker - The Handbook of Hydraulic Filtration

Types & Locations of Filters

Comparison of Filter Types and Locations
FILTER
LOCATION ADVANTAGES DISADVANTAGES
Suction • Last chance • Must use relatively
(Externally protection for the pump. coarse media,and/or large
Mounted) housing size, to keep
pressure drop low due to
pump inlet conditions.
• Cost is relatively high.
• Much easier to • Does not protect
service than a downstream
sump strainer. components from pump
wear debris.
• May not be suitable for
many variable volume
pumps.
• Minimum system protection.
Pressure • Specific component • Housing is relatively
protection expensive because it
• Contributes to overall must handle full system
system cleanliness level. pressure.
• Can use high • Does not catch wear
efficiency, fine filtration, debris from downstream
filter elements. working components.
• Catches wear debris from pump

Return • Catches wear • No protection from
debris from components, pump generated
and dirt entering contamination.
through worn cylinder • Return line flow surges
rod seals before it enters may reduce filter
the reservoir. performance.
• Lower pressure • No direct component
ratings result in lower protection.
costs. • Relative initial cost
• May be in-line or is low.
in-tank for easier
installation.
Off-Line • Continuous “polishing” of • Relative initial cost is high.
the main system hydraulic • Requires additional space.
fluid, even if the system is • No direct component
shut down. protection.
• Servicing possible without
main system shut down.
• Filters not affected by flow
surges allowing for optimum
element life and performance.
• The discharge line can be
directed to the main system
pump to provide supercharging
with clean, conditioned fluid.
• Specific cleanliness levels
can be more accurately
obtained and maintained.
• Fluid cooling may be easily
incorporated.

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