A backward surge of pressure
from downstream to upstream of the filter. Can be the
result of closing a valve or air entrapped in a liquid
system.
BACK WASH
Reversed flow through a
filtration media, as an attempt to clean or “regenerate”
a filter.
BAFFLE
Component of a housing
which constitutes a stage when used; removes liquid
and solids by impingement; may be either upstream or
downstream of the basic filter medium. May also be a
plate to protect filter elements from the velocity of
flow into a housing.
BAG-HOUSE
An air filtration structure
utilizing fabric filter bags for the purpose of removing
solid particulate from the gas stream; dust collector.
BAG-ON-CAGE
The concept of selling
both the bag and cage as one unit. Normally installed
together by the plant.
BAR
A unit of pressure. One
bar = 14.5 psi.
BASKET
Element for a basket strainer.
A device normally using a screen as its medium for removal
of coarse bulk solids.
BASKET STRAINER
A vessel for the removal
of coarse bulk solids from liquids, air or gas. The
element is usually a steel perforated basket, or a mesh
lined basket.
BCP
A design code for pressure
housing based on the manufacture’s best commercial
practice.
BETA RATIO
The ratio of the number
of particles colliding with the filter to the number
of particles passed through the filter. Also, an indication
of how a filter performs throughout the life of the
filter. B10 represents the filtration ratio at 10 micrometers
of the ratio of the upstream to downstream particles
larger than 10 micrometers.
BLEED THROUGH
Particulate migration through
the interstices of the filter bag fabric.
BLINDING
Fabric blockage by dust,
fume, or liquid not being discharged by the cleaning
mechanism, results in a reduced gas flow of increased
pressure drop across the filter media.
BLIND SPOTS
A area of the filter media
where no filtration takes place. Also referred to as
dead areas.
BLOWDOWN
The use of pressure to
remove liquids and/or solids from a vessel.
BOYLE’S LAW
If the temperature of a
given kind of gas is held constant, the volume of a
sample of gas varies inversely with the pressure.
Bridging
material of particulate
blockage across an opening, often of a pore or filter
medium.
BROWNIAN MOTION
The continuous zig-zag
motion of suspended minuscule particles. The motion
is caused by impact of the molecules of the fluid upon
the particles.
Brust presure
The pressure causing rupture.
The inside-out differential pressure that causes outward
pressure on the structural of a filter medium, filter
or housing.
BUBBLE POINT PRESSURE
A test to determine the
maximum pore size openings of a filter.
BUNA-N
A synthetic rubber gasket
material, used for vessel closures, flanges and filter
elements.
BURSTING STRENGTH
General - A material’s
ability to resist rupture by pressure. Specific - Force
required to rupture a fabric by distending it with the
force applied at right
angles to the fabric plane under specified conditions.
Usually expressed in pounds per square inch.
BY-PASS
A condition that occurs
when the filter media is violated and permits unfiltered
fluid to pass through.
