This document discusses different types of filters used in pharmaceutical processes. It begins by introducing filtration and the factors that affect filtration rates. It then explains several filtration theories and mechanisms. The document discusses various filtering media and factors that influence media selection. Finally, it describes several common filter types used in pharmaceuticals, including bag filters, cartridge filters, air filters, HEPA filters, gas filters, and strainers.

1. Topic: Theory and factors
affecting filtration, discuss
diferent types of filters used in
pharmaceutical
Md. Tanvir Islam
Id:123-29-417
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2. Content
• Introduction
• Filtration
• Factors affecting filtration
• Rate of filtration
• Factors affecting rate of filtration
• Theory of filtration
• Mechanism of filteration
• Filtering media
• Factors affect the selection of filtering media
• Different types of filters
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3. • Introduction: Although filters don’t play as
glamorous a role as the actual machines or
operational concepts, industrial filters are an
important part of any manufacturing process.
• Industrial filters are used in several different
industries, including pharmaceutical, food and
beverage, cosmetic and chemical. Without
efficient filters, the end products would be of
poor quality and the safety element wouldn’t be
there.
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4. Filtration
• Is a process of separating liquids form solids
by means of a porous medium.
• Is a unit operation .
• The porous medium used for the purpose
of the filtration is called the filter
• The fluid which has passes through the
filter is called the filtrate.
• The particles larger than the pores of the
filter are retained on the surface of the
filter medium
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5. • The ability of the filter- medium to eliminate
solid particles from a fluid is called retention.
• Fluids are of two types o Liquids - Gases
• Suspension of solids in liquid is often referred
to as slurry.
• During filtration, the suspended solid
materials build up a filter bed on the filter
medium and may resist filtration, this is
referred to as filter cake.
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6. Factors affecting filtration
• Properties of the liquid
•  Density, viscosity, corrosiveness etc.
• Properties of the solid
 Particle shape, particle size, particle
size distribution, compressibility of solid
• Proportion of solids in the slurry.
• Objective of filtration
 Whether to collect solid or liquid
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7. • Rate of filtration
• Filter slurry as quickly as possible
• Rate of flow through the capillaries of the
filter medium and filter cake
• Factors affecting rate of filtration
• Area of filter surface.
• Resistance of the filter medium and filter
cake.
• Viscosity of the filtrate
• The pressure difference across the filter
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8. Theory of filtration
• The flow of liquid through a filter follows the basic rules that
govern flow of any liquid offering resistance.
The rate of flow may be expressed as Rate = driving force /
resistance .The rate may be expressed as volume per unit time
and the driving force has a pressure differential. Resistance is
not constant since it increases as solids are deposited on the
filter medium.
The rate concept could be stated as:
where; V= volume of filtrate,
T = time,
A= filter area,
P= total pressure drop through cake and filter medium.
m = filtrate viscosity,
a = average specific cake resistance
W= weight of dry cake solid R= resistance of filter medium
and filter.
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9. Any convenient units may be used in this equation, since
inconsistencies are absorbed in the cake and filter
resistances. The practical limitation of this equation is that
the constants must be determined on the actual slurry
being handled.
It is convenient to summarize the theoretic relationship as
(area of filter) x (pressure difference)
Rate of Filtration =
(viscosity) x (resistance of cake and filter)
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10. Mechanisms of filtration
• Straining:
– Simplest filtration process.
– Particles are bigger than the pores.
– Particles retain on the filter
• Impingement:
– Occurs when the particles moving along the liquid strike on object and where
some will follow the stream lines and some will be collected / re-entrained
• Entanglement:
– The filter medium having a porous felt / a cloth with a nap
– The particles get entangled in the mass of fibers.
• Attractive forces:
– The particles are attracted on to the filtrate medium.
_ Effected by straining mechanism
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11. • Filtering media:
• Selection of suitable filtering media is depend on the
purpose of filtration and quantity to be filtered
• Ideal filter medium should be
• inert
• able to confirm the maximum passage of liquid while
retaining the solid
• able to withstand against the filtration pressure
• Factors affect the selection of filtering media
• Acceptable resistance to mechanical wear
• Good removal competence / ability to discharge cake
easily and effectively
• Resistance to chemical attack
• Minimum cost
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12. Different types of filters:
Bag filter:
Filter Bags are made of felt material, which has
the advantage of providing three dimensional
filter media and offers both, a surface and depth
filtration effect.
• Filter Bags are available in different types of
filter media in different ratings. Polypropylene
filter bag offers a broad range of chemical
compatibility and is suitable for many
applications
• Bag filter is mainly used for the preparation of
adhesives, fruit juices, petroleum products and
high viscosity fluids
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13. Cartidge filters:
Bag filters: 13

14. Cartidge filters:
• Cartridge filters are the machines which is used in filtration
purpose by uses the filtration technology of removing solid
matter and suspended impurities from a fluid stream by
passing it through a variety micro porous filters,
ultrafiltration units, green sand cartridge filters, activated
carbon cartridge filters, diatomaceous earth and
multimedia cartridge filtersCartidge filters:
• Cartridge filters are the machines which is used in filtration
purpose by uses the filtration technology of removing solid
matter and suspended impurities from a fluid stream by
passing it through a variety micro porous filters,
ultrafiltration units, green sand cartridge filters, activated
carbon cartridge filters, diatomaceous earth and
multimedia cartridge filters
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15. Cartidge filters
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16. Air filters
• Air filters are an important part of most
industrial processes, as they remove dust, dirt
and other particles from the air. Most air
filters consist of a mesh that catches the
particles when air is forced through.
• If the air must be protected from gases and
odors as well as particles, a high efficiency
particulate air filter is used.
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17. HEPA filter
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18. Gas filters
Gas filters are a type of industrial filters that helps
to remove contaminants or particulates from a
dry or liquid gas stream. Depending on the
situation, the contaminants may be solid or
liquid.
Some of the different elements and accessories for
gas filters include:
• Gas filter separators
• Coalescers
• Gas scrubbers
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19. 19
gas filter

20. Strainers
• Strainers often become part of the manufacturing
process when the process contains solids that are
too large to be caught up in other types of filter
media. Strainers consist of baskets that can be
removed and cleaned out regularly to prevent
them from being bogged down.
• Some strainers can be cleaned without
interrupting the system, while others will cause
some disruption each time they are cleaned.
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21. 21
strainer