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Institute of Technology, NIRMA UNIVERSITY1
Design and Analysis of
Screw Conveyor
Presented by :
Gandhi Keyur(08MME004)
M.Tech (CAD/CAM)
Guided by :
Dr. D. S. Sharma
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Institute of Technology, NIRMA UNIVERSITY2
Outline of Presentation
• Introduction to Screw Conveyor
• Major Screw Conveyor Components
• Types of Screw Flight
• Types of pitch
• IS code using for designing
• Design of screw conveyor
• Matlab program for screw conveyor design
• Modeling of screw conveyor
– Exploded View of Screw Conveyor
• Powder property and screw conveyor capacity
• Effect of vortex motion on the Volumetric Performance of Enclosed Screw
Conveyors
• System for Conveyor Equipment Selection
• Future Work of Project
• References
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Institute of Technology, NIRMA UNIVERSITY3
Introduction to screw conveyor
• Screw conveyors are widely used for transporting and/or
elevating particulates at controlled and steady rates.
• They are used in many bulk material applications in industries
ranging from industrial minerals, agriculture (grains),
pharmaceuticals, chemicals, pigments, plastics, cement, sand,
salt and food processing.
• They are also used for metering (measuring the flow rate)
from storage bins and adding small controlled amounts of
trace materials such as pigments to granular materials or
powders.
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Institute of Technology, NIRMA UNIVERSITY4
Major Screw Conveyor Components:
• Hopper or Bin
• Stationary screw casing (tubular, open or
covered trough)
• Rotating screw.
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Types of Screw Flight
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Types of pitch
Standard Full Pitch P/D = 1
Used for conveying material horizontally
or on slight inclines.
Half Pitch P/D = 0.5
Used in screw feeders, also in conveyors
where material is being conveyed up an
incline.
Double Flight Full Pitch P/D = 0.25
Used in conveyors where an even discharge
of materials is required.
Ribbon
Used in conveyors to convey sticky materials.
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Cut
Used in conveyors where mixing
materials is desired.
Cut and Fold
Used in conveyors where high levels
of mixing materials and increased
retention time is desired.
Varied Pitch
Used in screw feeders, short pitch
below inlet, full pitch beyond to allow
material loading to drop.
Cone with Consistent Pitch
Used in screw feeders where an
even loading across the inlet length
is desired.
Cone with Varied Pitch
Used in screw feeders where a
specific loading across the inlet
length is desired.
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IS code using for designing
• IS 5563 :1985 Screw conveyor for
industrial use
• IS 13324 :1982 Screw Feeders
• IS 12960 :1990 Determination of power
requirement of screw
feeder – general
requirement
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Institute of Technology, NIRMA UNIVERSITY9
Design calculation
• Q = V.ρ = 60 ∏/4 D2
.S.n.ψ.ρ.c
– V = volumetric capacity (m3
)
– ρ = Bulk Density of the material (kg/m3
)
– D = nominal diameter of screw conveyor(m)
– S = screw pitch (m)
– N = R.P.M. of screw
– Ψ= loading efficiency of screw
– C = factor to take into amount the inclination of screw
conveyor
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Institute of Technology, NIRMA UNIVERSITY10
Matlab program for screw conveyor design
• Q = input('Enter the capacity of conveyor in tons / hour : ')
• th = input('Enter the inclination of conveyor degree : ')
• if th>=0&&th<5
• inclinationfactorC=1
• elseif th>=5&&th<=9
• inclinationfactorC=.9
• elseif th>=10&&th<=14
• inclinationfactorC=.8
• elseif th>=15&&th<=19
• inclinationfactorC=.7
• elseif th==20
• inclinationfactorC=.65
• else
• inclinationfactorC=.5
• end
• Length = input('Enter the length of conveyor in metres : ')
• Bulk_Density = input('Enter the Bulk Density of conveying material in kg/cubic metre : ')
• conveying_material = input('Enter the type of conveying material n press 1 for abresive,n press 2 for midly abresive and n press 3
for non abresive and free to flow : ')
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Institute of Technology, NIRMA UNIVERSITY11
Matlab program for screw conveyor design
• switch conveying_material
• case 1
• progress_resistance_coefficient = 4
• loading_efficiency = 0.125
• %fprintf('loading efficiency of conveying material is=%fn',loading_efficiency)
• case 2
• progress_resistance_coefficient = 2.5
• loading_efficiency = 0.275
• %fprintf('loading efficiency of conveying material is=%fn',loading_efficiency)
• case 3
• progress_resistance_coefficient = 2.5
• loading_efficiency = 0.425
• %fprintf('loading efficiency of conveying material is=%fn',loading_efficiency)
•
• otherwise
• disp('Unknown conveying_material ')
• end
• Pitch_to_Diameter_Ratio = input('Enter the Pitch to Diameter Ratio of conveyor between 0.75 to 1.0 :')
• speed = input('Enter the speed of conveyor in RPM :')
• diameter_of_conveyor = ((Q*4)/
(22/7*60*Pitch_to_Diameter_Ratio*speed*loading_efficiency*Bulk_Density*inclinationfactorC))^(1/3)
• fprintf('diameter_of_conveyor =%f metren',diameter_of_conveyor)
• power_req = Q/367*progress_resistance_coefficient*Length + Length * sin(th*3.14*2) + (diameter_of_conveyor * Length)/20
• fprintf('power_req = %f kilowatt n',power_req)
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Matlab run program
• Enter the capacity of conveyor in tons / hour : 50
• Q =
• 50
• Enter the inclination of conveyor degree : 15
• th =
• 15
• inclinationfactorC =
• 0.7000
• Enter the length of conveyor in metres : 25
• Length =
• 25
• Enter the Bulk Density of conveying material in ton / cubic metre : 1.6
• Bulk_Density =
• 1.6000
• Enter the type of conveying material
• press 1 for abresive,
• press 2 for midly abresive and
• press 3 for non abresive and free to flow : 1
• conveying_material =
• 1
• progress_resistance_coefficient =
• 4
loading_efficiency =
0.1250
Enter the Pitch to Diameter Ratio of conveyor between 0.75 to 1.0 :1
Pitch_to_Diameter_Ratio =
1
Enter the speed of conveyor in RPM :50
speed =
50
diameter_of_conveyor =
0.5331
diameter_of_conveyor =0.533112 metre
power_req =
13.0963
power_req = 13.096333 kilowatt
Ans : Diameter = 533 mm
Power req. = 13.KW
For 50 ton/hour output capacity
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Modeling of screw conveyor
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Institute of Technology, NIRMA UNIVERSITY14
EXPLODED VIEW OF SCREW CONVEYOR
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Powder property and screw
conveyor capacity
• Coarse powders will flow into the screw easier than
fine powders.
• The screw capacity will also be higher if a dense
powder is used.
• Particle with a round shape have lower internal
friction that results in a greater screw capacity.
• The clearance and the free length of the intake have
a big influence on screw capacity.
• No correlation between conveying length and
conveyor capacity was found.[1]
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Institute of Technology, NIRMA UNIVERSITY16
Effect of vortex motion on the Volumetric
Performance of Enclosed Screw Conveyors
• Vortex motion arises as a result of internal friction,
friction between the granular material and surface of
the helical blade.
• The vortex motion, together with the degree of fill
govern the volumetric efficiency. [2]
• = Rotational or vortex efficiency
• = Fullness Efficiency =
• = Average height of material on the screw
surface.
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System for Conveyor Equipment Selection
• The system provides the user with a list of conveyor solutions
for their material handling needs along with a list of suppliers
for the suggested conveyor devices.
• Conveyor types are selected on the basis of a suitability score,
which is a measure of the fulfillment of the material handling
requirements by the characteristics of the conveyor.
• The Expert System(ES) approach to conveyor selection
provides advantages of unbiased decision making, greater
availability, faster response, and reduced cost as compared to
human experts.
• The computation of the score is performed through the
Weighted Evaluation Method
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Conveyor category selection screen [3]
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Attribute importance specification screen [3]
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FUTURE WORK OF PROJECT
• Design of screw conveyor.
• Programming of screw conveyor design
• CFD analysis of screw conveyor.
• Prediction of screw conveyor performance at
different operating condition.
– The rotational speed of the screw.
– The inclination of the screw conveyor.
– The volumetric fill level of the bulk material.
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References
1) Alma Kurjak ,The vertical screw conveyor- powder properties and Screw
conveyor design , SE-221 00 Lund ,Sweden January 2005.
2) A.W. Roberts, The influence of granular vortex motion on the volumetric
performance of enclosed screw conveyors, Callaghan NSW, 2308,
January 1999.
3) Daniel J. Fonseca*, Gopal Uppal, Timothy J. Greene, A knowledge-based
system for conveyor equipment selection, Elsevier 26 (2004) page no.
615–623.
4) Jianjun Dai, John R. Grace, Biomass screw feeding with tapered and
extended sections, Powder Technology 186 (2008) 56–64, Elsevier
5) W. McBride, P.W. Cleary, An investigation and optimization of the ‘OLDS’
elevator using Discrete Element Modeling, Powder Technology 193
(2009) 216–234, Elsevier
6) T. K. Ray, Mechanical handling of materials 2004,92-105
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