Page 173 - Parker - Process filtration

Glossary of Filtration Terminology
(continued)
Channeling:
Tendency for contaminant to pass through a low-
density area of an inconsistent fi lter medium or
around cartridge seal points.
Clarifi cation:
Filtration of liquids containing small quantities of
solids.
Classifi cation:
Arrangement or separation of particles by size.
Collapse Pressure:
Pressure across a fi lter cartridge or bag great
enough to cause it to collapse.
Colloids:
Suspension of submicron particles in a continuous
fl uid medium that will not settle out of the medium. liquid that will not mix.
Contaminant:
Undesirable insoluble solid or gelatinous particles
present in a fl uid.
Cycle Length/Filter Life:
The duration, measured in time or volume, that a
fi lter can operate effectively between replacement
and/or cleaning.
Density:
Mass per unit volume of a substance under specifi ed
conditions of temperature and pressure.
Depth Media:
Generally fi lter media that are thick and provide
graded density construction. Wound, resin-bonded
and melt blown cartridges fall into this category.
Typically, these cartridges result in lower fl ow rates,
higher initial pressure drops and lower dirt holding
capacities than surface media (pleated).
Differential Pressure/Pressure Drop:
Difference in pressure between two points in a
system. In fi lters, this is usually measured between
the inlet and outlet of the fi lter housing (is a
determining factor of fi lter service life).
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APPENDIX
Dirt Holding Capacity:
The weight of a contaminant fed to the fi lter during a
test to reach a predefi ned terminal pressure drop.
Double Open End (DOE):
A fi lter cartridge confi guration such that both ends
are open and require housings with knife edge
sealing devices.
Effi ciency:
The ability of the fi lter medium to remove particles
from the fl uid stream.
Effl uent/Filtrate:
The fl uid that has passed through the fi lter.
Emulsion:
A suspension of small liquid droplets within a second
Extractables:
Inorganic or organic elements or compounds in the
fi lter medium that have leached into the fi ltrate.
Usually reported by weight or percent.
FDA:
To be used for fi ltration of foods, beverages, drugs
or cosmetics. All fi lter construction materials must
comply with regulations established by the Food and
Drug Administration (FDA) as listed in CFR Title 21.
Filter Media:
Plural of fi lter medium.
Filter Medium:
The permeable material used for a fi lter that
separates particles from a fl uid passing through it.
Filtration:
Separation of particulate matter from a fl uid by
passing the fl uid through a permeable medium that
will trap a percentage of the particulates.
Filtration Effi ciency:
That fraction of suspended particles retained by
the fi lter.