Filter composed of layers
of sand, graded in particle size so that the coarse
particles face the unfiltered flow. Commonly employed
in filtration of water supplies. Filters of this type
(perhaps incorporating crushed coke and grit) have occasionally
been used for removal of particles fromgases. See deep
bed.
SCAVENGER
A filter or element in
the bottom of a filter that recovers the liquid heel
that remains in a filter tank at the end of a cycle.
SCFD
Standard Cubic Feet per
Day.
SCFM
Standard Cubic Feet per
Minute. The volume of gas flow per minute at standard
temperature and pressure conditions (70°F at sea
level).
SCREEN
Covering for filter element
for physical protection; also used as a basic material
for a separator element or the basket strainer.
SCRUBBER
Any device in which a contaminant,
solid or gaseous, is removed from a gas stream by impacting
it with liquid droplets. (Types include spray towers,
packed towers, cyclone scrubbers, jet scrubbers, venturi
scrubbers and impingement scrubbers.)
SEAL NUT
Gasketed nut which holds
element cap in place.
SELF-CLEANING
Filtering device designed
to clean itself by the use of a blowdown or backwash
action. Medium is commonly a screen mounted on a cylindrical
drum or device that removes bulk solids from large flow
rates. Baffle in first stage aids in the separation
of solids by impingement. Blowdown may be continual
or intermittent and operated either manually or automatically
by instruments.
SEPARATOR/FILTER
A vessel which removes
solids and entrained liquids from another liquid or
gas, using some combination of a baffle and/or coalesce,
filter or separator elements. A vessel may be single
stage, two stage, or single or two stage with prefilter
section for gross solids removal. The usual application
is the removal of water from gas or another immiscible
liquid. General reference to term applies the equipment
capable of both separation and filtration to specific
degree of efficiencies.
SEPTUM
Any permeable material
that supports the filter media.
SERIAL FILTRATION
Filtration through two
or more filters of decreasing pore size one after the
other to increase throughput, filtration efficiency,
or to protect the final filter.
SERVICE LIFE
The length of time an element
operates before reaching the maximum alloawable pressure
drop.
SINGED FINISH
The process of removing
fibers from a cartridge or fabric by passing over a
flame or other heat source. The process creates a smooth
finish that inhibits fiber migration.
Slug
Dirt, carbon, water and
chemical compounds found in oils.
SLUG CATCHER
A particular separator’s
design able to absorb sustained in-flow of large liquid
volumes at irregular intervals. Usually found on gas
gathering systems of other two-phase pipeline systems.
A slug catcher may be a single large vessel or a main
folded system of pipes.
SLURRY
Thin, watery suspension;
a material to be filtered.
SPECIFICATION
The document that describes
in detail the requirements with which a product or service
has to comply.
STATIC PRESSURE
The potential pressure
exerted in all directions by a fluid at rest. For a
fluid in motion it is measured in a direction normal
to the direction of flow. Usually expressed in inches
water gauge when dealing with air.
STATIC PRESSURE DROP
The change in static pressure
as the gas stream goes through the filter media and
the filtration system ductwork.
STOCK’S DIAMETER
Diameter of a sphere having
the same density and the same free speed as the particle
when moving in a homogeneous fluid, of the same density
and viscosity, under conditions of laminar flow.
STOCK’S LAW
A physical law which approximates
the velocity of a particle falling under the action
of gravity through a fluid. The particle will accelerate
until the fractional drag of the fluid just balance
the gravitational acceleration, after which it will
continue to fall at a constant velocity known as the
terminal or free-settling velocity.
SUMP
Collecting area of a housing,
located downstream from the coalesce elements, in which
coalesced droplets of the dispersed phase are deposited;
also called water leg. May also be used to collect solids
in applications where gross solids are present in a
stream; also called sump.
SURFACE AREA
The total area of an element
that is exposed to a approaching flow.
SURFACE FILTRATION
A process that traps contaminants
larger than the pore size on the top surface of the
filter, usually a PTFE membrane. Contaminants smaller
than the specified pore size may pass through the membrane
or may be captured within the membrane by some other
mechanism.
SURFACE TENSION
Also “interfacial
tension.” Tendency of the surface of a liquid
to contract to the smallest area possible under the
existing circumstances. Difined as a force in dynes
action on a line 1 cm long lying in the surface of the
liquid.
SUSPENSION
Solids or liquids that
are held in other liquids.
SWING BOLT
Type of housing head closure
which reduces service time. Opposite ot thru-bolt flange
where studs and nuts are used, such as with ASA type
flanges.
