Solids deposited on the
filter medium during filtration.
CAKE RELEASE
Ability of medium to allow
clean separation of the cake from the medium.
Candle filter
A reusable filter consisting
of a tube made from ceramic or metal. Flow is from the
outside-in with particulate accumulating on the outside
of the candle. The candle can be cleaned by various
means, including back-pulsing, heats chemical, etc.
CANOPY
An air filtration structure
utilizing fabric filter bags for the purpose of removing
solid particulate from the gas stream; dust collector.
CAP-ELEMENT
Component which covers
one end of an element and holds the element in place
in the housing. Sometimes called a yoke.
CAP-END
The end of many types of
filter cartridges. In particular, the shallow annular
dish into which the ends of a pleated paper filter cylinder
are adhesively bonded to form a pleated paper cartridge.
CAPILLARY
A very thin tube, in filtration,
is used as an example to describe pores in a membrane.
CAPTURE VELOCITY
The air velocity at any
point in front of the hood or at the hood opening necessary
to prevent particulate material and contaminant gases
from escaping to the working area.
CARTRIDGE
A filter for the clarification
of process liquids containing small amounts of solids.
Made of a porous medium, it is used in a vessel,which
performs the actual filtration process.
CAUSTIC
A Sodium Hydroxide (NaOH)
solution.
CELLULOSE
The preponderant and essential
constituent of all vegetable tissues and fibers. Ideal
cellulose material provides for a variety of filtration
efficiencies, low initial pressure drop, high wet strength
and solids retention.
CENTER CORE
Material formed into a
tube or cylinder for structural purpose to permit a
cartridge to retain its original physical form.
CENTER-ROD
The component of a vessel
used for mounting the cartridge in the vessel, usually
made of a round bar material. A center pipe can also
be used for the same purpose, but is made instead with
perforated effect and directs flow through the cartridge.
CENTER SEAL
Part which forms seal between
two elements when one element is one the top of another
element. May also be called an adoptor.
CENTER TUBE
Component of an element
or cartridge which supports the medium at the center
of smallest diameter.
CENTIPOISE (cP)
(N s/m2; N = Newton) A
unit of absolute viscosity. One centipoises equals 0.01
stoke.
CENTISTOKE (cSt)
A unit of kinematic viscosity
(m2/s). One centistokes equals 0.01 stoke
CENTRIFUGATION
The process of separating
two substances of differing densities by high speed
spinning to create centrifugal force. Typically used
to separate suspended particles from liquid.
CFM
Cubic Feet per Minute.
A unit of measure for volumetric gas flow.
CHAR
A carbonaceous material
in dust usually incompletely burned fuel, which has
larger particles than the rest of the dust.
CHARLES’ LAW
If the pressure on a given
kind of gas is held constant, its density is inversely
proportional to its absolute temperature. See Avogadro’s
Law and Boyle’s Law.
CIP
Clean-in-place. A method
whereby a filter medium can be chemically cleaned to
restore performance without requiring removal from the
system.
CLARIFICATION
To clear a liquid by filtration,
by the addition of agents to precipitate solids, or
by other means.
Clarifier
An apparatus for the removal
of settleable solids from a fluid by gravity.
CLARITY
Clearness of a liquid measured
by the amount of contaminants remaining.
CLEAN AIR PLENUM
The baghouse area, through
which gases are directed, located on the clean side
of the bags above the tubesheet in a pulse-jet baghouse.
CLEAN WATER PRESSURE DROP
Differential pressure across
the new filter as measured using clean water at a particular
flow rate.
CLOGGING
The process of solids being
removed by a filter, block the filter increasing differential
pressure.
CLOTH WEIGHT
Fabric weight expressed
in oz/ yard2.
COAGULATION
Growing together of minute
particles to form larger ones, which are called flocs
and are easier to filter. Also referred to as flocculation.
COALESCER
Mechanical device which
unites discrete droplets of one phase prior to being
separated from a second phase. Can be accomplished only
when both phases are immiscible. Requires a tight medium
which is preferentially wettable and, by its nature
of being tight, is also a good filtering material. Good
coalescing permites gravity separation of the discontinuous
phase. Coalescing may be accomplished by only a coalescer
cartridge when the specific gravities of the two phases
are widely separated. As the gravities difference becomes
less, the two stage principle is generally required
where finely coalesced discontinuous droplets are repelled
by the second stage separator cartridges.
COALESCING
The action of uniting of
small droplets of one liquid preparatory to its being
separated from another liquid.
COATING
Immersion of filter media
in a solution to provide the fibers with a coating that
will lubricate and thereby reduce self-abrasion.
Colapse presure
The outside-in differential
pressure that causes the structure of a filter medium
failure of filter element.
COLLECTION EFFICIENCY
A measure of dust collector
ability to remove particulate from the inlet gas expressed
in percent.
COLLECTION SURFACES
Clean-in-place. A method
whereby a filter medium can be chemically cleaned to
restore performance without requiring removal from the
system.
COLLECTION SURFACE AREA
The total flat projected
area of collecting surface exposed to the active electrical
field (effective length x effective height x 2 x number
of gas passages).
Coloid
Very small, insoluble nondiffusible
solid or liquid gelatinous particles that remain suspension
in a surrounding liquid. Solids usually on the order
of a 0,2 microns or less.
COMBINATION FABRIC
A woven fabric containing
both filament and spun yarn of the same or different
fibers. The filament yarn is normally used length-wise
for strength and spun cross-wise to provide surface
area.
COMPATIBILITY
Term used in relation to
the non-reactivity of filter materials with the substance
to be filtered.
COMPLIANCE
An indication or judgement
that the product or service meets the agreed requirement
of the relevant specification; also the state of meeting
the requirements.
COMPRESSIBILITY
Degree of physical change
in filter cake particles when subjected to normal pressures.
Also a factor when selecting gasket material.
CONCENTRATE
The non-filtered stream
leaving a crossflow filter system. Also called Return,
Recycle, Recirculation, or Reject.
CONDENSATE
The liquid formed by the
drop in pressure and hence temperature of steam.
CONDENSATION
The process of cooling
a vapour below its boiling point in order to liquefy
it.
CONSISTENCY OF FEED
Usually refers to the ratio
of solids to liquid in the feed.
CONTAMINANT
Any undersirable particle
or impurity in a stream.
Continuous phase
Basic product flowing through
a filter or filter separator, which continues on through
the system after being subjected to solids and/or other
liquid separation.
CONTROL DAMPER
A device installed in a
duct to regulate the gas flow by degree of closure.
Examples: butterfly or multi-louver.
CONVERSION
In general, refers to the
changing of one type of medium to another type for a
specific purpose.
CORONIZING
A heat cleaning process
for fiberglass fabric to burn off the starches (used
in processing) usually at temperatures of 1,000`F. for
a short duration.
CORROSION
Chemical attack on metallic
surfaces, usually caused by moisture and/or acid dew
point excursions. Removal of solids and water reduces
the effect or speed of corrosion in many cases, and
in other cases, corrosion inhibitors are used to reduce
the effect of corrosion.
COUNT OF CLOTH
The number of ends (lengthlongitudinal
yarns) and picks (cross-horizontal yarns) per inch in
a woven fabric.
CRITICAL OPERATING PRESSURE
Pressure above which filtration
or separation equipment may produce reduced efficiency
or fail to function properly.
CROSSFLOW ( TANGENTIAL FLOW)
FILTRATION
A mode of filtration where
the fluid moves across the surface of the filter material
tangentially. The fluid is recirculated and passes the
filter material several times. These have the effect
of cleaning away debris build up from the surface which
prolongs flow. A small stream of clean liquid known
as the permeate passes through the filter material.
RO and UF operates under this mode. Some MF systems
can be found operating like this.
CYCLONE
A conical-shaped vessel
for separating mixed sized particulates from the gas
stream. The vessel has a tangential entry at the largest
diameter allowing the larger particles to drop out and
be removed from the bottom of the cone while smaller
particulate exits overhead with the majority of the
gas stream.
