The document discusses different types of air filters, including coarse filters, fine filters, HEPA filters, ULPA filters, carbon air filters, and UV light air filters. It explains that air filters are composed of fibrous materials that remove particles from the air to maintain good indoor air quality. The effectiveness of a filter depends on factors like air velocity, particle size, dust loading, and filter material properties. Common applications of air filters include hospital operating rooms, medical clean rooms, toxic environments, and air conditioning systems.

1. EZHIL RAJ.S
AIR FILTERS
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2.  Air filter is a device composed of fibrous materials.
 It removes solid particulates such
as dust, pollen, mould, and bacteria from the air.
 Air filters are used in applications where air quality
is important, notably in building ventilation systems .
Air filter
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3. Coarse filters
Fine filters
HEPA
ULPA
Carbon Air Filters
UV light air filters
TYPES
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4.  A prefilter used in air-conditioning systems to remove large
particles such as dust and lint.
 This type of filter is usually reusable after being vacuumed or
washed.
 Range from less than 50 microns to 2000 microns.
COARSE FILTERS
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5.  HEPA is an acronym for “High Efficiency Particulate Air”
 This type of air filter can remove at least 99.97% of dust,
pollen, mold, bacteria and any airborne particles with a size
of 0.3 micrometers (μm)
HEPA FILTER
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6. ULPA is an acronym for "Ultra Low Penetration
Air (filter)"
An ULPA filter can remove from the air at least
99.999% .
 With a size of 100 nanometres (0.1 µm) or
larger.
ULPA FILTERS
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7.  It can readily be used to absorb particles and
trap odors.
Carbon air filters use activated carbon to trap
chemicals and gases, and can also filter
cigarette smoke
CARBON AIR FILTERS
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8. Ultraviolet light air filters use a reaction that
occurs when titanium dioxide is exposed to UV
light.
High intensity UV (240-280 nm) is strong
enough to break down most carbon based
organic compounds, making UV light air filters
a good companion to HEP filters in medical
applications
UV LIGHT AIR FILTERS
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9.  Filters with higher efficiency will have higher pressure drop.
 pressure drop can be calculated by
PRESSURE DROP
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10.  It shows how well a filter removes airborne particles.
 the filtration efficiency E, can be calculated by
 Where,
Cdown is the average concentration of particles at the
downstream location.
Cup is the average concentration of particles at the
upstream location before the filter.
FILTRATION EFFICIENCY
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11.  It is a function of the filtration area.
 The velocity of the air is given by
V=Q/A
where,
Q is the volumetric flow rate through the filter
A is the filtration area.
The standard HEPA filter has an initial 1.0 in. w.c. (249 Pa)
pressure drop at 250 fpm (1.3 m/s) face velocity.
A high capacity HEPA filter has a 1.4 in. w.c. (348 Pa) pressure
drop at 500 fpm (2.5 m/s), with the same quality air filtration
AIR VELOCITY
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12. FILTRATION EFFICIENCY FOR TWO
DIFFERENT VELOCITIES
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13.  Air Velocity Through The Filter Medium.
Particle Size.
Dust Loading On The Filter.
 Filter Packing Density.
 Fiber Diameter And Thickness Of The
Material.
FACTORS THAT AFFECT FILTRATION
EFFICIENCY
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14. Hospital operation theatre
Clean room in medical industry
Toxic environment
Air conditioning
Maintain proper IAQ in living room , office etc
APPLICATIONS
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