1. A REPORT ON
-DUST COLLECTION SYSTEM-
SUBMITTED BY
Varun Raj - 2013A4PS288G
Prepared in partial fulfillment of the Practice School I
Course No. ( BITS F221 )
AT
-CARBORUNDUM UNIVERSL LTD-
A Practice School-I station of
BIRLA INSTITUTE OF TECHNOLOGYAND SCIENCE, PILANI
-Goa Campus-
May-June 2015

2. ACKNOWLEDGEMENT
I am greatly thankful to BITS Pilani for giving me the opportunity to work in an industry and
learn their ways.
I am also thankful to Carborundum Universal Ltd for engaging me and providing me an
appropriate project with a lot of scope for learning.
Also my PS Instructor, Mr Anoop Kumar has been of great help in making me understand
certain aspects of working in an industry as well as in successfully completing this PS
program.
Special thanks to my guide and mentor Mr. Saji Skariah, Head of Engineering, for sharing his
knowledge, recommending appropriate books and most of all for being immensely patient
with me.
My colleagues and the workers at Carborundum Universal Ltd have helped in the smooth
functioning of these two months and have been a healthy moral support.

3. BIRLA INSTITUTE OFTECHNOLOGYAND SCIENCE,PILANI
Practice SchoolDivision
Station: Carborundum Universal Ltd
Centre: Kochi, Kerala
Duration: May 22, 2015-July 16, 2015
Date of Submission: July 14, 2015
Title of Project: Design optimization of DC systems
Completed by: Varun Raj - 2013A4PS288G
PS instructor : Anoop S Kumar
PS coordinator : S Shankaranayanar
Project coordinator : Mr. Saji Skariah
Project Guide : Mr. Saji Skariah

4. Abstract: This project includes the methods involved for improving a present Dust
Extraction system. I started off by studying the working of Baghouse DC system. Then
moved on to the losses involved with poor ducting. The different factors that can be applied
to improve the efficiency (like duct angles, ducting taper etc.) were included and submitted in
a Preliminary report.
Furthermore the fabrics and the power of the motor was studied and an idea of using different
types of fabrics in a single bag was suggested. This improves the combined efficiency of the
baghouse like heat resistance, excellent dust cake discharge and so on.
Signature of Student: Signature of PS faculty:
(Varun Raj) (Mr. Anoop Kumar)
Signature of Project Guide
(Mr. Saji Skariah)
Date:
Place:

5. CONTENTS
I. ACKNOWLEDGEMENT
II. ABSTRACT
1. INTRODUCTION
1.1. COMPANY PROFILE
1.2. DUST COLLECTION
1.3. PROJECTOBJECTIVE
2. DC SYSTEM
2.1 WHAT IS DC SYSTEM
2.2 TYPES
2.3 USES & APPLICATION
3. PROCESSESINVOLVED
3.1 PROCESSMAPPING
3.2 EQUIPMENTS
3.2.1 JAW CRUSHER
3.2.2 ROLLCRUSHER
3.2.3 CYCLONE SEPARATOR
3.2.4 BAGHOUSE FILTER
4. IMPROVEMENT
5. CONCLUSION
6. BIBLIOGRAPHY
7. APPENDIX

6. 1. INTRODUCTION
With increased local and global attention being given to the control of air pollution,
containment of nuisance dust in all industrial applications is becoming increasingly important.
This calls for the proper design, installation, operation and maintenance of dust collection
equipment. Since its inception, the fabric style dust collector (baghouse) has offered companies
the ability to effectively capture airborne particulate from an air stream. Whether toxic or not,
containment of particulate is necessary to provide a healthy and clean work environment.
1.1 COMPANY PROFILE
CUMI was founded in 1954 as a tripartite collaboration between the Murugappa Group, The
Carborundum Co., USA and the Universal Grinding Wheel Co. Ltd., U.K.
The company pioneered the manufacture of Coated Abrasives and Bonded Abrasives in India
in addition to the manufacture of Super Refractories, Electro Minerals, Industrial Ceramics and
Ceramic Fibres. Today the company's range of over 20,000 different varieties of
abrasives, refractory products and electro-minerals are manufactured in ten locations across
various parts of the country.
With state-of-the art facilities and strategic alliances with global partners, CUMI has achieved
a reputation for quality and innovation. CUMI is one of the five manufacturers in the world
with fully integrated operations that include mining, fusioning, wind and hydro power stations,
manufacturing, marketing and distribution.
Almost all of CUMI's ten manufacturing facilities have received the ISO 9001:2008
accreditation for quality standards. A well connected marketing and distribution network of
offices and warehouses in India and abroad, ensure that service to customers is given prime
importance.
CUMI's constant innovation and product upgradation, through in-house R&D and strategic
alliances with global leaders in grinding technology, have not only ensured it market leadership

7. in India and abroad, but also international recognition as a manufacturer of quality abrasives
and a provider of total grinding solutions. CUMI's products are being exported to 43 countries
spread across North America, Europe, Australia, South Africa and Asia.
High inflation, fluctuating currencies and a subdued overall business confidence impacted the
first half of the year 2014-15. Although the second half showed marginal improvement in
economic indicators, many industries that CUMI serves in India and across the world such as
Automotive, Infrastructure, Utilities and Mining showed a declining trend. In this uncertain
scenario, CUMI’s consolidated revenues grew by 8% over the year.
In Kerala CUMI has three main offices: Kakkanad, Kalamasseri and Koratty.
The Kakkanad branch handles the processing of micro grit, which is the reduction of size into
micron range (10-50 microns). While the Koratty branch is the producer of Silicon Carbide.
I had the good fortune of working with their mother branch Kalamasseri which was instituted
in 1964 .In this factory they have a total of two main plants and couple of smaller plants .
Plant 1- Brown Fused Alumina Plant
The raw material for Brown fused alumina (BFA) production is calcined bauxite. The process
is batch type here. An arc is formed between the raw material in the electric arc furnace. At
high temperature change of state occurs from low to upper grade. Water cooling is provided
for all furnaces. The impurities will settle down. A single run takes 8hours for completion. The
product from furnace is kept 3-4 days for natural cooling. Then, it is broken into pieces
manually. During pellatization sulphur smell occurs. Broken crude is then sent to grain
processing (GP) plant. Here the bigger particles are broken into 10cm particle. Sound and air
pollution is high in the grain processing plant. Different types of crushers are used in the GP
plant for obtaining different sized particles. Dust issue occurs during the sieving process.
Cyclone separators and bag filters are provided to reduce the dust formed. For removing
magnetic impurities low intensity magnet as well as high intensity magnet is used. The grains
which require heat treatment is sent to a rotary kiln.

8. Plant 2-White Fused Alumina Plant
The raw material for White fused alumina (WFA) production is calcined bauxite. The process
here is continuous type rather than the batch type for BFA production. Tilt furnace is used in
the process to ensure continuous production. Here also natural cooling is done. Process
occurring is same as that in the plant 1. Only difference is crushing and grain processing are
done at the same plant here but in BFA production it is done at two different plants. Here also
sound and air pollution problems are there. Bag filters and cyclone separators are used for dust
reduction.
The first two are the main plants and the next two are the subsidiary plants.
Plant3: It involves the manufacturing of CUMI Blue their innovative new product.
Plant4: It involves the manufacturing of Alumina Zirconia.
The company’s primary products are the BFA and WFA.
And my project was assigned in the BFA plant under Mr. Saji Skariah , who overlooks the
entire engineering department of CUMI (Kalamasseri)
The company staffs were also very cooperative and provided valuable insight into their
manufacturing processes.

9. The 5S system is their hidden card with which they are able to achieve manufacturing
excellence:
Figure 1
1.2 DUST COLLECTION
About 40 percent of combustible dust explosions reported in the US and Europe over the last
25 years have involved dust collectors. Dust collection systems are now a primary focus of
inspections. The five elements required for a dust explosion can be pictured as a pentagon, as
shown in Figure 2. The three elements labelled in black are those in the familiar fire triangle:
fuel (combustible dust), an ignition source, and oxygen. For a dust explosion, two more
elements (labelled in red) are required: dust dispersion at or greater than the dust’s minimum
explosible concentration (the lowest dust concentration that will propagate a combustible dust
deflagration or explosion; MEC) and confinement of the dust cloud within equipment or a
building.
Put simply, a dust explosion occurs when an ignition source touches a dust cloud with a
concentration at or greater than the dust’s MEC. A dust cloud with this concentration can result
when a layer of dust thicker than 1⁄32 inch on equipment, piping, overhead conduit, or similar

10. components is pushed into the air by some event, such as the pressure wave from a relief
device’s operation. When an ignition source—such as a spark or the flame front
from an equipment explosion—touches the cloud, the dust can explode with devastating
impact. To mitigate a dust collection system’s explosion risk, we need to focus on preventing
dust accumulation in the system, preventing ignition, and providing explosion prevention or
protection at the collector.
Figure 2
1.3 PROJECT OBJECTIVE
The aim of this project was to suggest improvements in the design of the DC systems which
are in place. This was achieved by the study of various dust collection system parameters and
clues we can take to find out faulty designs. For example the ducts which carry the dust to the
cyclone chamber and then to the baghouse filters should never meet at right angles as this can
reduce the CFM and can result in the falling out of dust from the flow stream.

11. 2. DC SYSTEM
Figure 3
Dust collectors are used in many processes either to recover valuable granular solids or powder
from process streams or to remove granular solid pollutants from exhaust gases or air prior to
venting to the atmosphere. Dust collection is an online process for collecting any process
generated dust from the source point on a continuous basis.
Dust collectors may be a single unit construction or a collection of devices used to separate
particulate matter from the process air.
They are often used as an air pollution control device to maintain or improve air quality.
2.1 WHAT IS DUST EXTRACTION SYSTEM
Dust Collector:
As the name rightly suggests, it is a system used to enhance the quality of air released from
industries and commercial processes by collecting dust and other pollutants from air or gas.
With the growing pollution from manufacturing industries, dust collection systems have
become an essential component in the industry.

12. 2.2 TYPES OF DUST COLLECTORS
Five main types of dust collectors are:-
1. Inertial separation,
2. Fabric filters,
3. Wet scrubbers,
4. Electro static precipitation,
5. Unit collection.
Speaking about Fabric filter dust collectors;
Commonly known as BAG HOUSE, Fabric collectors use filtration to separate dust particles
from dusty air/gas. They are one of the most efficient and cost effective type of dust collectors
available and can achieve a collection efficiency of more than 99% for very fine particulate.
Dust laden gas/air enter the bag house, and pass through the filter bags that acts as filters. The
bags can be of woven or felted cotton, synthetic or glass fibre material, in either a tube or an
envelope form/shape.
Pre-Coating
To ensure filter bags have a long usage life, they are generally coated with a filter enhancer
(pre-coat).The use of chemically inert lime stone (calcium carbonate) is most common as it
maximizes efficiency of dust collection (including fly ash) via formation of what is called a
dust cake or coating on the surface of the filter media. This not only traps fine particulates but
also provides protection for the bag itself from the moisture and oily or sticky particulate which
can bind the filter media. Without a pre-coat the filter bags allow fine particulate to bleed
through the bag filter system, especially during start up, as the bag can only do part of the
filtration leaving the finer parts to the filter enhancer dust cake.

13. PARTS: Fabric filters generally have the following parts;
1. Clean pleanum,
2. Dusty pleanum,
3. Bag, Cage,
4. Tube plate,
5. Screw,
6. Compressed air header,
7. Blow pipe,
8. Housing and hopper,
9. Fan & Motor.

14. Figure 4
Bag houses are characterized by their cleaning system
In Carborundum Universal LimitedTM, we use a ‘Pulse- jet’ cleaning system:
PULSE-JET: This type of bag cleaning (also known as pressure-jet cleaning) is the most
common. A high pressure blast of air is used to remove the dust from the bag. The blast enters
the top of the bag tube, temporarily ceasing the flow of dirty air. The shock of air causes a wave
of expansion to travel down the fabric. The flexing of bags shatters and discharges the dust
cakes.
The air burst is about 0.1 second and it takes about 0.5 seconds for the shock wave to travel
down the length of the bag. Due to its rapid release, the blast of air does not interfere with the

15. dirty air flow. Therefore, pulse-jet bag house can operate continuously and are not usually
compartmentalized. The blast of compressed air must be power full enough to ensure the shock
wave will travel the entire length of bag and fracture the dust cake.
Figure 5
2.3 USES & APPLICATION
A dust collector is a system used to enhance the quality of air released from industrial and
commercial processes by collecting dust and other impurities from air or gas. Designed to
handle high-volume dust loads, a dust collector system consists of a blower, dust filter, a filter-

16. cleaning system, and a dust receptacle or dust removal system. It is distinguished from air
cleaners, which use disposable filters to remove dust.
A dust collection systemis an air quality improvement system used in industrial, commercial,
and home production shops to improve breathable air quality and safety by removing
particulate matter from the air and environment. Dust collection systems work on the basic
formula of capture, convey and collect.
First, the dust must be captured. This is accomplished with devices such as capture hoods to
catch dust at its source of origin. Many times, the machine producing the dust will have a port
to which a duct can be directly attached.
Second, the dust must be conveyed. This is done via a ducting system, properly sized and
manifolded to maintain a consistent minimum air velocity required to keep the dust in
suspension for conveyance to the collection device. A duct of the wrong size can lead to
material settling in the duct system and clogging it.
Finally, the dust is collected. This is done via a variety of means, depending on the application
and the dust being handled. It can be as simple as a basic pass-through filter, a cyclonic
separator, or an impingement baffle. It can also be as complex as an electrostatic precipitator,
a multistage baghouse, or a chemically treated wet scrubber or stripping tower.

17. Figure 6
3. PROCESSES INVLOVED
Brown Fused Alumina – Production Process
The key production processes are as follows:

18. 1. Mining of bauxite.
Figure 7
2. Calcining of bauxite.
Figure 8
3.Fusing of bauxite with iron and carbon. >>>The resulting product from the
fusing processes is: Brown Fused Alumina

19. Figure 9
4.Tilt Furnace
Figure 10

20. 5. After the fusing process, the ingot with brown fused alumina needs to cool
own.
6. Breaking the ingot content (breaking the Brown Fused Alumina).
7. Crushing of brown fused alumina lumps.
8. Grinding of brown fused alumina lumps/bricks.
9. Sieving of brown fused alumina into different sizes.
10. Packing of the brown fused alumina grains.
3.1 PROCESS MAPPING

22. 3.2 EQUIPMENTS
3.2.1 Jaw Crusher
Figure 11
Its working principle is: Motor drives belt and belt pulley, makes moving jaw up and down
through eccentric shaft. When the moving jaw is up, the angle between lining plate and moving
jaw becomes large, and this will push moving jaw plate close to the fixed jaw plate. During
this process, the material is crushed and ground, thus the crushing will be done. When the
moving jaw is down, the angle between lining plate and moving jaw becomes small, the moving

23. jaw plate will leave the fixed jaw plate on account of the effect of pulling bar and spring, and
then the crushed material will be discharged from the lower opening of the crushing room.
The adjustment of discharging port is quick and lightweight; it can meet the needs of different
crushing process without adding or subtracting shims, only through mechanical adjustments.
The easy-to-install modular design ensures the jaw crusher installation simple and convenient.
Integral installation of motor and crusher saves installing space, making it is possible to install
crusher in any sturdy conditions. Precisely balanced design allows higher crushing speed
without bolts, making installation simple. In addition, the balance design reduces the force of
the V-belt and bracket, reducing installation costs. The delicate balance design and discharge
opening design ensure the best economy and low running costs, while a wider option further
improve the crushing performance, the options include: pulley, flywheel safety cover, remote
control hydraulic adjustment system.
3.2.2 Roller Crusher
Figure 12

24. Roll crusher is driven by the motor through the pulley or gear shaft opposite two rollers rotate,
or were driven by two motors rotate two rollers. Double roll crusher with material by weight
and the friction between the roll surface into the crusher and discharge within the broken.
Through changes in two double roll crusher roller bearing pads between the number, or the use
of worm gear to adjust the mechanical adjustment between the two rollers the force generated
to maintain the discharge opening gap, so that double-roll crusher even granularity.
Double roll crusher spring is the insurance unit. When a hard material or transport of bulk
materials fall into the crushing chamber cannot be crushed, the Roll of the force increases, the
movable Roll can be left by the movable bearing compression spring, increasing the gap two
Roll to discharge a hard object, and then by the spring restoring force to the movable Roll back
to the original position.
3.2.3 Cyclone Separator

25. Figure 13
A high speed rotating (air) flow is established within a cylindrical or conical container called
a cyclone. Air flows in a helical pattern, beginning at the top (wide end) of the cyclone and
ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the
centre of the cyclone and out the top. Larger (denser) particles in the rotating stream have too
much inertia to follow the tight curve of the stream, and strike the outside wall, then fall to the
bottom of the cyclone where they can be removed. In a conical system, as the rotating flow
moves towards the narrow end of the cyclone, the rotational radius of the stream is reduced,
thus separating smaller and smaller particles. The cyclone geometry, together with flow rate,
defines the cut point of the cyclone. This is the size of particle that will be removed from the
stream with a 50% efficiency. Particles larger than the cut point will be removed with a greater
efficiency, and smaller particles with a lower efficiency.

26. 3.2.4 Baghouse Filter
Figure 14
The baghouse filter involves sucking in the air, thereby creating vacuum in the ducting. This
results in dust (formed at different locations) being effectively collected.
The air, containing the dust, is then forced to pass through a baghouse containing filter bags
made of specific fabrics and appropriate dimensions so that the particles of a specific size(
prescribed by PCB) is not allowed to pass.
This is a continuous process and the dust accumulates on the bag filters. This is released by
means of a Jet Pulse as explained earlier. The timing of the pulse is decided by the engineers
by accounting for various factors like fabric dust release properties, CFM of air flow etc.
Unlike electrostatic precipitators, where performance may vary significantly depending on
process and electrical conditions, functioning baghouses typically have a particulate collection
efficiency of 99% or better, even when particle size is very small.

27. 4. IMPROVEMENT
After research in the topic, I suggest a few things that could help improve the
present system.
4.1 AIR VELOCITY
Keeping the conveying air velocity in every part of the duct within a reasonable range will
prevent two problems:
Too low an air velocity will cause the dust to drop out of the air and build up inside the duct,
and, depending on the dust’s characteristics, too high an air velocity will waste energy, erode
the duct, or, if the dust is moist or sticky, cause the dust to smear on the duct wall.
A conveying air velocity between 3,500 and 4,000 fpm (17.5 and 20m/s) is a reasonable starting
point for designing the system. If the system handles an extremely fine, lightweight material
that won’t clump together, like cotton dust, velocity can be reduced to 3,000 fpm; if it handles
a very heavy material, like lead dust, a higher velocity of 4,500 to 5,000 fpm will be required
to efficiently carry the dust all the way to the cyclone chamber.
4.2 DUCTING
How duct sections are joined in a system also affects the conveying air velocity. If incorrectly
designed, the point where ducts join to merge two airstreams can slow the air velocity, in turn
causing the dust to drop out and accumulate in the duct.
Following are some visual clues that indicate the air velocity in the ducts isn’t high enough to
prevent dust from dropping out of the air:

28. Clue 1: Mainduct diameter doesn’t enlarge after branch
junctions.
In Figure a, two 8-inch-diameter branch ducts join an 8-inch-diameter main duct, and the main
duct’s downstream diameter is the same after each junction. At A, before the first branch
junction, the 4,200-fpm air velocity required to convey the dust is reasonable and can be
achieved by the system’s design airflow of 1,500 cfm. But because the duct diameter doesn’t
enlarge after the branch junctions, the required air velocity increases exponentially.
Solution: The more economical solution is to enlarge the downstream duct. This will solve the
problem that results from not upgrading the exhaust fan—that is, that C gets most of the airflow,
B gets some, and A gets very little. To ensure that the duct’s diameter is large enough after a
branch duct joins it, follow this rule of thumb: The sum of the areas of the upstream branch
ducts should roughly equal the area of the downstream duct. Thus, at B:
82 + 82 = 128~112 or 121
so the main duct diameter at B should be changed to 11”.

29. Clue 2: Main duct is blanked off.
In Figure b, an 8-inch diameter main duct, A, is blanked off. A 4-inch-diameter branch duct,B,
joins the main duct at a Y junction that enlarges from 18 to 9 inches, and the downstream main
duct, C, is 9 inches in diameter. But with A blanked off, the required air velocity through the
4-inch-diameter duct (B) is now 3,900 fpm (350-cfm airflow). The exhaust fan might be able
to pull an airflow of no more than 600 cfm through B and C, which would drop the air velocity
at C from the required 4,100 fpm to 270 fpm.
Solutions: Two solutions are possible: You can replace the entire duct between B and the
system’s dust collector with smaller duct to achieve an adequate conveying velocity. Or, as a
much cheaper alternative, you can remove the blank flange and replace it with an orifice plate
that delivers 1,500-cfm air flow at the system’s available static pressure; the orifice plate has a
hole at its centre that’s sized to meet the system’s airflow and pressure drop requirements.

30. Clue 3: Poor duct junctions don’t maintain conveying velocity.
In Figure c, an 8-inch-diameter duct section abruptly joins a 20-inch-diameter section. At the
system’s 1,400-cfm design airflow, the conveying air velocity is 4,000 fpm the 8-inch section,
but it drops abruptly to 650 fpm in the 20-inch section, which will cause the dust to drop out
of the air.
Solution: In this case, the solution is to replace the 20-inch duct section with 8-inch duct. The
duct diameter should stay at 8 inches until the next branch junction; after that junction, the duct
should be enlarged to maintain the air velocity, following the rule of thumb.

31. Clue 4: Duct blast gate isn’t locked in position.
Blast gates in ducts add artificial airflow resistance to balance the airflow in individual duct
branches. For each blast gate, only one position is correct to balance the airflow in all branches.
Solution: Set this and other duct blast gates to meet the system’s design airflow and then lock
the gates in place. You can avoid this problem altogether by designing the dust collection
system for the correct airflow balance without using blast gates, which is called balance by
design.

32. 4.3 TYPE OF FABRIC
The type of fabric and the filtration velocity are important issues to be considered when Fabric
Filters are being specified. The choice of fabric and filtration velocity, (the speed that the air
passes through the filtering fabric), are determined by the consideration of the below mentioned
factors.
• Dust characteristics
• Type
• Particle Size and shape
• Dust loading
• Temperature
• Chemical properties
• Application characteristics
• Source of dust
• Emission limit to be achieved
• Operating cycle
Many fibres are available in the industry like Polypropylene, Polyester, Nomex, Ryton, PTFE
etc. A few of the ones relevant to us (BFA) with their properties are listed below:
1. Polyester (P.E):- Recommended for Pulse jet applications. A manufactured fibre in
which the fibre forming substance is any long chain synthetic polymer composed of at
least 85% by weight of an ester of a dihydric alcohol and terephtalic acid. This material
is a thermoplastic. Fibre is available under various trade names: Dacron® (duPont),
Enka Polyester® (American Enka), Fortrel® (Fiber Industries/Celanese), and Kodel®
(Eastman Chemical).
In the presence of moisture, fibres will hydrolyse thereby weakening the the overall
strength of the fabric.

33. 2. Acrylic Fibre: - Acrylic fibres are man-made fibres, in which the fibre forming
substance is any long chain polymer composed of at least 85% acrylonitrile units, and
the remainder a copolymer. Acrylic is non-thermoplastic. Where polyesters are not
suitable, because of potential hydrolysis, acrylics offer a combination of abrasion
resistance and resistance to wet heat degradation, particularly under acid conditions.
Homopolymer felt is a candidate for hot gas applications of less than 284 degrees F.
Temperature resistance of copolymers is less, 250°F degrees. Acrylic felts are used in
drying raw flour, coal, gold and copper ores, galvanizing, and low temperature flue gas
applications. Polyester is superior for most dry heat applications.
3. Teflon: - It is composed of long chain carbon molecules in which all of the available
bonds are completely saturated with fluorine. These strong carbon-to-fluorine bonds
create fibres that are exceptionally stable to both heat and chemicals. Teflon is the most
chemically resistant fibre used in conventional dust filtration. Teflon is not affected by
any known solvents except some prefluorinated organic liquids at temperatures above
570 degrees F. Exposure to temperatures above 550 degrees F. will cause some
decomposition, although it is slow to develop. Teflon bags shrink when exposed to high
temperatures, especially in length. The low friction properties of Teflon fibres provide
excellent cake discharge. In addition, Teflon® fibres’ chemical inertness and resistance
to dry and moist heat degradation makes it ideal for use under severe conditions. Teflon
needled felt is extremely expensive. Recently a lower cost version, Tefaire , has been
introduced. This felt is a blend of 85% Teflon and 15% fiberglass fibres. Commercial
uses are limited to extreme chemical environments where the advantages of Teflon
fibres’ great chemical resistance outweighs cost disadvantages.
4. HEPA: - High Efficiency Particulate Air filter is the maximum efficiency available in
particulate filtration. Rated for temperatures up to 275°F. Usually offered as a static
after filter following a dust collector; however, a pulse cleaned version is available.

34. Refer below table for a comparative study of the different fabrics used in the industry
Table 1
4.4 MOTOR SPECIFICATIONS
1HP = 0.746KW
HP= Torque x RPM
5250
Air HP= CFM x TP
6356
Brake HP= Air HP
Efficiency

35. 5. CONCLUSION
1. The efficiency of the DC system can be improved by simple steps mentioned in the
duct design. ( Refer Section 4.2 )
2. The specifications of the motor are
HP- 75
RPM- 1475
KW- 551
Shaft RPM- 1071
3. An innovative idea of using different fabrics in the same bag filter was suggested.
For example, Teflon has a high dust cake release property compared to polyester so,
instead of using only felt polyester (in practice currently), we can add a layer or two of
Teflon or Tefaire ( low cost ) on the outside as polyester has a poor dust cake release
as compared to Teflon.

36. 6. BIBLIOGRAPHY
 www.wikipedia.com
 www.google.com
 Dust Collection Handbook
 ‘Designing a dust collection system to meet NFPA standards’ by Gary Q. Johnson
 ‘Give your plant a Dust control tune up’ by Bernard H. Schonbach
 GORE Filtration Products
 CUMI EMD Hand-out
 Efficiency of Dust Collection systems
 Mr Aravindakshan Nair (Maintenance Manager of Excel Glasses Pvt Ltd.)

37. 7. APPENDIX
1. BFA- Brown Fused Alumina
2. CFM- Air Volume in Cubic Feet per Minute
3. DC- Dust Collector
4. FPM- Air Velocity in Feet Per Minute
5. MEC- Minimum Explosible Concentration
6. PCB- Pollution Control Board
7. SP- Static Pressure
8. TP- Total Pressure (= SP+VP )
9. VP- Velocity Pressure. Kinetic pressure in direction of flow necessary to make
air at rest flow at a particular velocity.