Design & Fabrication of Screw Conveyor INTRODUCTION 1.1 GENERAL SCREW CONVEYORS are one of the oldest and simplest method of moving bulk material and consist primarily of a conveyor screw rotating in a stationary trough. Conveyors find application mostly in productive factories where transportation is fairly of continuous and uniform character, the individual loads being very high. Screw conveyors are compact, easily adapted to congested locations and can be mounted horizontally, vertically and inclined. Their supports are simple and easily installed. These versatile conveyors can be used to control the flow of material in processing operations which depend upon accurate batching or as a mixer, agitator or stirrer to mix and blending dry or fluid ingredients provide crystallization or coagulation action or maintain solutions in suspension. Screw conveyors can be effectively sealed to prevent dust or fumes from escaping or dirt or moisture from entering. They can be jacketed to serve as a dryer or cooler, or furnished in a wide variety of materials to resist corrosion, abrasion or heat. Screw conveyors are used as a earth augers to dig past holes or to bore under highways for installation of culverts. They are also used extensively on threshing machines hay balers fodder blowers and many other farm machines. C.O.E. & T.,Akola 1
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Design & Fabrication of Screw Conveyor
INTRODUCTION
1.1 GENERAL
SCREW CONVEYORS are one of the oldest and simplest method of
moving bulk material and consist primarily of a conveyor screw rotating in a stationary
trough.
Conveyors find application mostly in productive factories where
transportation is fairly of continuous and uniform character, the individual loads being very
high.
Screw conveyors are compact, easily adapted to congested locations and
can be mounted horizontally, vertically and inclined. Their supports are simple and easily
installed.
These versatile conveyors can be used to control the flow of material in
processing operations which depend upon accurate batching or as a mixer, agitator or
stirrer to mix and blending dry or fluid ingredients provide crystallization or coagulation
action or maintain solutions in suspension.
Screw conveyors can be effectively sealed to prevent dust or fumes from
escaping or dirt or moisture from entering. They can be jacketed to serve as a dryer or
cooler, or furnished in a wide variety of materials to resist corrosion, abrasion or heat.
Screw conveyors are used as a earth augers to dig past holes or to bore
under highways for installation of culverts. They are also used extensively on threshing
machines hay balers fodder blowers and many other farm machines.
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Design & Fabrication of Screw Conveyor
1.2 SCOPE
This manual is helpful in designing of screw conveyors using calculations in metric
units.
Saving of labour and time.
To increase the output:
With the help of conveyors more work can be done with a given floor space, blocks are
avoided.
To utilize existing building for new purposes:
Conveying plant enables two or more detached building to be connected together and
used for several operations in propersequence.
Reducing personal hazardous:
The enclosing trough can be made tight enough to contain toxic dust and vapours.
Material in transit can be heated or cooled by jacketing the trough.
1.3 OBJECTIVE
The aim of this project is to "design and fabricate a screw conveyor" to convey cement
at 7 TPH for a distance of one meter.
This design is in accordance with CEMA HANDBOOK NO .350
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Design & Fabrication of Screw Conveyor
LITERATURE REVIEW
2.1 DIFFERENT TYPES OF CONVEYING EQUIPMENT FOR BULK
MATERIALS
2.1.1 BELT CONVEYOR
Belt conveyors are the most versatile and widely used of all conveyors.
They are capable of handling higher tonnages over greater distances at lower costs per ton
then any other type of conveyor – and often at lower cost per than any other means of
transportation. Yet, they are used extensively for small and moderate capacity systems
because of their ability to handle practically any kind of material economically and
dependably. Since the material is carried on the belt, tees conveyors are suitable for
handling certain corrosive materials that would quickly attack the vital parts of all metal
conveyors.
The range of the sizes, which may be handled on belt conveyors limited
only by the width of the belt.
Materials may vary from extremely fine Chemicals to lumpy ore, stone,
coal or pulpwood logs. Since belt conveyors are relatively self cleaning to or more
dissimilar materials may be handled at different times by the same conveyor.
Belt conveyor systems are capable of operating around the clock without
loss of time for empty return trips or delays for loading and unloading. Belt conveyors are
adaptable to the parts of material flow in any plant. They occupy comparatively little space
and can avoid existing equipment and structure. Long distance belt conveyors systems will
negotiate terrain and paths of travels that are not practical or economical for more other
method of transportation.
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Design & Fabrication of Screw Conveyor
Bulk materials, flowing continuously and uniformly from belt conveyors,
may be distributed to desired location. In addition to transportation and distribution, belt
conveyors may be used to perform many other functions such as weighing, blending,
sampling and stock piling. Also belt conveyors may be supported and housed at lower cost
then most other facilities for transporting similar large volumes.
The principal factors contributing to comparatively low operating costs of
belt conveyors systems are low power requirements, long life of wearing parts, low lab
our cost of replacing parts, low cost of inspection and attendance, low cost of loading and
unloading per ton handled and maximum safety of personnel.
BELT CONVEYOR
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Design & Fabrication of Screw Conveyor
OSCILLATING CONVEYOR
2.1.2 OSCILLATING CONVEYORS:
Oscillating conveyors move materials in a uniform flow by the upward and
forward oscillating motion of a continuous metal trough mounted on sturdy, inclined
reactor legs. This conveyors are ideal for handling all granular, free flowing materials as
well as hot, abrasive, dusty, stringy and other difficult- to- handle materials or where
contamination or corrosion is a problem. Oscillating conveyors are also used cooling,
heating and drying. They have leak proof trough in which there are no moving parts, and
can be enclosed and sealed for dustproofor a gas-tight operation.
Oscillating conveyors can be modified for many special uses. Trough can be
made in a special widths or they can be constructed of tubes or pipes; they may also be
divided lengthwise for simultaneous handling of different materials or parts. Oscillating
conveyors can also be used as picking and sorting tables. Standard
conveyors can also be use on modify to suit many process applications such as drying,
Cooling, screening, etc.
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Design & Fabrication of Screw Conveyor
BUCKET ELEVATORS
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Centrifugal discharge elevator
bucket elevator
Positive discharge bucket elevator
Design & Fabrication of Screw Conveyor
2.1.3 BUCKET ELEVATORS:
The typical bucket elevator consists of series of buckets mounted on a chain
or belt operating overhead and foot wheels. Take-ups are provided as a means to
compensate for variations in length of chain or belt due to temperature changes,
atmospheric conditions, or wear. A steel casing usually encloses the bucket line and the
head and put machinery. The type of elevator and material handled determine the bucket
selection.
Chain is used on elevators caring heavy loads, hot materials, or those, which
pack between the buckets and a belt. Rubber covered or treated fabric belts are used an
elevators handling grains, cereals, and many other, free - flowing, abrasive materials. The
head and the foot machinery components have been selected to best suit the service
requirements of the individual's elevator.
Selection of the proper type of bucket elevator depends largely on capacity
requirements and the characterstics of the materials to be handled.
CENTRIFUGAL DISCHARGE BUCKET ELEVATOR
Elevator of this design predominates in the bulk handling of free flowing,
fine and loose materials with small to medium size lumps. Buckets, mounted at spaced
intervals, are loaded by scooping up materials from the boot or by feeding the material into
them.
Material is discharged by centrifugal action as the buckets pass over the
head wheel. These elevators are made in several types and are suitable for many
requirements.
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POSITIVE DISCHARGE BUCKET ELEVATORS
Elevators of this design operate at low buckets speeds suitable for handling
light, fluffy, fragile materials and those having a tendency to stick in the buckets. Buckets,
at spaced intervals, are loaded by scooping up material from the boot or by feeding the
material into them. After passing over the head wheels, the buckets are inverted over the
discharge spout, providing a positive discharge of material.
CONTINUOUS BUCKET ELEVATORS
Elevators of this design are made in a number of types for handling many
bulk materials ranging from light to heavy and from fines to large lumps. Buckets are
spaced continuously and loaded by direct feeding. Their close spacing prevents spillage
between buckets. As buckets discharge, the material flow over the preceding bucket, who's
front and projecting sides form a chute, to the discharge spout.
INTERNAL DISCHARGE BUCKET ELEVATORS
Internal discharge elevators provide excellent means for the continuous,
gentle handling in bulk of relatively small articles such a stampings, castings, plastic chips,
pallets, bolts, nuts, rivets, granule chemicals, seeds, shelled nuts and similar materials.
Discharge can be on either side of casing through a chute or directly to a conveyor.
2.1.4 GRAVITY-DISCHARGE CONVEYOR ELEVATOR
The gravity – discharge conveyor – elevator is used to handle non-abrasive
bulk materials in vertical, or combination of horizontal and vertical paths. It derives its
name from the fact that material discharges from the buckets by gravity. Gravity conveyor
is easy to setup, as it does not involve any power drive.
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Design & Fabrication of Screw Conveyor
Because of the gentle pick-up and discharge of material the gravity-
discharge conveyor- elevator is primarily intended for use where breakage or degradation
of conveyed material is an important consideration. It is also suitable for lumpy materials
relatively large capacities and many other applications where comparatively economical
equipment is desired.
This conveyor - elevator consist of a conveying medium of modified v-
shaped buckets rigidly mounted at regular intervals between two strands of long pitch steel
roller chain, operating over suitably located comer sprockets and in open troughs or
enclosed casings as determined by the requirements of the installation.
Loading can be accomplished by means of a comer boot, or material can be
fed into the conveyor at any point along a lower horizontal run-in the latter instance the
buckets act as a scrapers, pushing the material forward to a corner where it is carried
around a curved trough and picked up by the buckets.
On vertical runs this machine functions as an ordinary bucket elevator.
Upon reaching an upper comer the conveyor line again assumes a horizontal position and
the buckets operate as scrapers. Material is restrained from spilling at corner by specially
constructed curved troughs.
Discharged from the conveyor can only be effected on horizontal runs
where opening occur in the trough bottom. Gates can be provided or the trough bottom
omitted to properly distribute material along the line of travel of the upper run.
2.1.5 FLIGHT CONVEYOR :
A flight conveyor consists of one or two endless power driven chains
carrying properly spaced scrapers or flights for moving material along the length of a
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Design & Fabrication of Screw Conveyor
stationary trough. Material fed into this trough is there by pushed along its length for
discharge at the end of the trough or trough intermediate discharge gates.
Typical materials, which can be satisfactorily handled with a flight
conveyor, are those, which are granular; lumpy; very free flowing; non-abrasive, and
mildly corrosive.
Flight conveyors are used for either horizontal or inclined paths and are
frequently installed where the angle of inclination is comparatively step.
Link - belt flight conveyors are simple in design, sturdily constructed of
durable materials, and provide an efficient, economical and dependable conveying
medium, reflecting the benefits of sound engineering experience.
Single strand flight conveyors with scraper flights are ideal for conveying
hot materials such as cement clinker and lime.
Double strand flight conveyors with sliding chain –suspended flights are
used for larger capacities and longer paths than single strand flight conveyors and can be
made to convey on both runs. The chain operates on flat renewable steel bars attached to
the trough.
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Design & Fabrication of Screw Conveyor
SKIP HOIST
2.1.4 SKIP HOISTS
Skip hoists are particularly adaptable to very high lifts and may be used to
elevate any bulk materials that can be handled in batches, including materials with large
lumps.
The skip hoist will convey virtually all materials with the exception of those
which are very fine, light or fluffy, contaminable, highly corrosive, or those having
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Design & Fabrication of Screw Conveyor
harmful, dusty or explosive properties.
The skip hoist consists of a bucket with or without counter weights or two
buckets balancing each other, a winding machine, wire rope, a steel structure with tracks,
means for loading and unloading the buckets and the necessary electrical apparatus and
lead sheaves.
As an effective method of unloading bulk materials, the skip hoist is
especially applicable to high lifts. The sip hoist is suitable for various combinations of
vertical and inclined paths of travel. It has few moving parts and the material being carried
does not contact these parts; therefore, maintenance is infrequent and simplified.
The link -belt hoist is known for its simplicity of construction, its
dependability and economy in operation. Operation may be manually controlled or fully
automatic.
There are three general types of skip hoist- the single non-counter-weighted
bucket, the single counterweighted bucket, and the type with balance buckets.
2.2 TYPES OF SCREW CONVEYORS
2.2.1 INCLINED UNITS:
Inclined screw conveyors, in general handle products that can be conveyed
in horizontal screw conveyors. Being compact, say contained and fully enclosed they can
be readily applied in congested areas. Feature insuring sanitation and ease of cleaning are
available.
For inclines of about 20 degrees or less, conveyor screws of regular pitch
operating in troughs are usually employed. Inclines above 20 degrees ordinarily require the
use of short pitch conveyor; screw operating in a tabular or shrouded trough.
2.2.2 VERTICAL UNITS:
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A vertical screw elevator is a unit that conveys material vertically. These
units can satisfy many conveying problems and have the further advantage of being
compacted, requiring less space than other forms of elevating equipment.
These units find it difficult to handle materials containing large lumps and
materials that are very dense or extremely abrasive.
Since we do not want to convey cement vertically, we consider either
inclined or horizontal screw conveyors.
“Draw backs of inclined screw conveyors”
The capacity of a given screw conveyor decreases with the increase of incline.
As the angle of inclination increases, there is reduction of flight (i.e. effective angle) as
it pushes against the material. Depending on angle of incline a certain portion of helical
flight does not urge the material forward. This causes material turbulence and
tumbling.
The 'U' shape of the conveyor trough is such that the material is allowed to fall back on
the top of the rotating screw. Again this increases the turbulence and cross sectional
loading.
Due to turbulence and tumbling of material, more horsepower is required than the
power required to normally conveying the material.
Due to the above -mentioned factors we select Horizontal Screw Conveyor, which
conveys cement horizontally.
2.3 CLASSIFICATION OF SCREW CONVEYOR DEPENDING UPON
TYPE OF FLIGHT USED
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Design & Fabrication of Screw Conveyor
1) Paddle conveyor screw.
This consists of a series of cut and folded flights mounted on the central
revolving shaft or pipe. In this the material is intentionally tumbled and sheared as it is
advanced along the casing by the pitch of the screw at every revolution. Friction between
the material and the revolving spiral tends to carry the material up one side and around
with the blade.
The capacity averages about 15% less than that of standard screw
conveyors, due to retarding action. Adjusting the angle of paddles can control conveying
action. They are used for mixing, blending, or stirring dry or fluid materials.
PADDLE CONVEYOR SCREW
RIBBON FLIGHT CONVEYOR SCREW
2. Ribbon flight conveyor screw:
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Design & Fabrication of Screw Conveyor
In this type of conveyor screw a steel bar rolled to form a continuous helical
ribbon flight fastened to the pipe or shaft by steel supporting lugs welded at spaced
intervals.
Variation of diameter, pitch, flight width or thickness can be furnished.
Also, this screw can be furnished with either continuous or sectional flights, lap or butt
welded together.
These are recommended for handling, sticky materials such as molasses, tar
or substances likely to build upon screw. The tendency of materials of this nature to adhere
and build up at the juncture of solid flight with the pipe is over corned by the open
construction of the ribbon flight.
Providing the periphery of ribbon flights with beveled edge improves
operation and reduces power consumption when handling materials which tend to pack or
trowel between flights and troughs. Consequently, beveled edge ribbon flight conveyor
screw is usually subjected to extremely heavy loads and construction is extremely
accordingly heavy loads and construction is extremely accordingly heavy and rugged. The
ribbons are supported on the pipe or shaft by steel lugs, generously proportional to resist
bending.
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Design & Fabrication of Screw Conveyor
HELICOID FLIGHT CONVEYOR SCREW
SECTIONAL FLIGHT CONVEYOR SCREW
To provide moderate mixing or stirring of materials being conveyed,
paddles can be furnished, spaced at intervals and set to partially oppose the forward flow,
called ribbon flight conveyor screw with paddle. Paddles are adjustable and may be set at
any angle, to produce the desired degree of agitation. They are used for light or medium
weight, fine, granular materials.
In multiple ribbon flight conveyor screw, the screw consists of two or more
ribbon flights of different diameter and opposite hand, mounted one within the other on the
same pipe or shaft by rigid supporting lugs. The other, thereby inducing positive and
through mixing moves material forward by one flight and backward.
3. Sectional flight conveyor screw:
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Design & Fabrication of Screw Conveyor
Sectional flight conveyor screws are made of individual flights; each
blanked from a flat steel plate and formed into helix. The flights are butt welded together
and fastened to the pipe, or shaft by intermittent or continuous welds with or without
formed steel end lungs. Sectional flights are formed with regular pitch approximately equal
to the diameter.
The pipe of a size carefully selected for adequate torsion strength and
resistance to excessive deflection, has internal collars at each end. These collars are
permanently inserted and have appropriate inside diameter to accept coupling or end
shafts.
Sectional flight conveyor screws are interchangeable with helical flight
conveyor screw of the same diameter and shaft size.
Sectional flight affords flexibility in choice of diameters, pitches and
thickness. When desired, sectional flights may be continuous welded to the pipe on one or
both sides, thus providing exceptionally rugged construction for the most severe conveying
application.
4. Helicoids type:
The helicoids flight conveyor screw is made of a helix, formed by flat steel
bar and mounted on a pipe or shaft. The helix, formed by special rolling equipment to the
required diameter, pitch and thickness, is a smooth, continuous one- piece flight.
By virtue of its one-piece construction, it possesses superior strength. The
absence of laps, rivets or welds on the carrying face of the flight promotes and maintains
cleanliness and reduces wear. The rolling process affects a hardening and smoothing of the
flight surface, which increases resistance to wear and reduces friction and power
consumption.
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Design & Fabrication of Screw Conveyor
The flight is fastened to the pipe, or shaft, by intermittent or continuous
welds and with or without formed steel end lungs. The pipe, of a size carefully selected for
adequate torsion strength and resistance to excessive deflection, has internal collars at
each end. These collars are permanently inserted and have appropriate inside diameters to
accept coupling or end shafts.
The assembled helicoids flight conveyor screw is solidly constructed and
exceptionally sturdy, and inherent balance permits operation at high speeds. Its distinctive
characteristics contribute in maximum efficiency, durability and economy.
Helicoids flight conveyor screws are interchangeable with sectional flight
conveyor screws of the sane diameter and shaft size.
Helicoids flighting is made with regular pitch approximately equal to the
diameter. It can also be furnished with other than regular pitch and in a wide range of
diameter, thickness and lengths to meet the most exacting requirements. For extremely
heavy duty the flighting may be continuous welded to the pipe or shaft on one or both
sides.
We select helicoids type of screw conveyor flighting.
METHODOLOGY
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Design & Fabrication of Screw Conveyor
3.1 DESIGN CONSIDERATIONS
The key to any successful screw design is, firstly through a thorough under
standing of the characteristics of the material to be handled.
Secondly the action of a screw conveyor is important to understand. It is
most important to have thorough knowledge of, and understanding of the way material
flows and effects of variation in the flow.
Capacities are usually given in TPH. Also the apparent density in the
material could vary. The conveyor size and speed must be based on maximum volume and
the apparent conveyed density of the material.
Surge loads should be taken in account.
3.2 DESIGN CALCULATIONS
Material Handled: Portland cement
Lump Size: Powder
Capacity required: 2.654 TPH [Tons Per Hour]
Length of conveyor: 0.75 c/c [Inlet Center To Outlet Center]
Referring to table get the following data:
1) Bulk Density: 65 -85 lbs per cubic feet
2) Material Class: A 2 7 Y
3) H.P. Factor F: 1.0
Taking the lower value of bulk density and converting it into tons per meter cube.
Bulk Density = 65 lbs per cubic feet
= l.0404 tons per meter cube
4) Component:2 D_From Table No. 1, we get
Now material class = A 27 Y where,
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Design & Fabrication of Screw Conveyor
A- Very fine, 100 mesh under
2- Free flowing - angle of repose 30 to 45 degrees
7- Mildly abrasive
Y-Aerates and becomes fluid.
By deleting last letter in material class, we get A 27
Locating this material class tables we find material Class A 2 7 comes in
Table no 2
This table No: 2 corresponds to Graph G-5
Capacity: 2.654 TPH
For converting TPH into cubic feet per hour we divide the capacity by the
lower bulk density.
Therefore,
Capacity = (2.654 TPH)/ (1.0404 Tons per meter cube)
= 2.55 meter cube per hour
Therefore,
Capacity in cubic feet per hour = (2.55 * 35.28)
Where, (35.28) is conversion factor.
Capacity = 90 cubic feet per hour
For finding the diameter of screw conveyor we refer the graph G-5
From the graph we select 6 inches diameter screw
Curve = 153 mm = 160mm (modified)
From table 12 standard pitch = 125
Putting these values in the formula for capacity
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Design & Fabrication of Screw Conveyor
C = 3.142/4*[(D*D-d*d)*p*k*B.D*(r.p.m.)*60
2.654= 3.142/4 * [(0.160 * 0.160-d*d)] 0.125
0.3*1.0404*60*60
Therefore d = 0.039m
= 39mm
Therefore taking "d = 40 mm".
We select an electric resistance welded (ERW)
A -class pipe. (Since the pipe is being used for light- duty work)
Standard available pipe outer diameter is "42.5" with 2.5mm wall thickness.
Therefore pipe inside diameter is 42.5-5 =37.5mm
Now c/c length of convey or is 0.75 meter
Adding the distance between the trough end inlet and outlet centers (i.e. pitch)
We get,
Conveyor overall length = 750+2*125
=1000mm
ESTIMATING THE HORSE POWER REQUIRED
We assume 100% loading and thus calculate the capacity. Using this
calculated capacity we calculate the required horsepower.
outtextxy(0,10,"************************************************************************"); outtextxy(5,400,"PRESS ENTER <---- FOR FURTHER CALCULATION"); getch(); closegraph(); } void design() { clrscr(); int inc,cd,j,d,t,f,n2,did,did1; f=1; long n1,fs; float d1,d2,n,p,c,x,y,l,rr,c1,cdf,hp,bhp,c2,dod,pid; float stdpitch[]={100,125,160,200,250,315,355,400,450,500,560,630}; clrscr(); cout<<"ENTER THE CAPACITY DESIRED IN TONS PER HOUR:"<<endl; cin>>c; c=c*35.28/1.0404; cout<<"ASSUMING CENTRE TO CENTRE DISTANCE=1000 MM:"<<endl; cd=1000*1; cout<<"SELECT THE SCREW DIAMETER FROM FOLLOWING STANDARD SIZES:"<<endl; cout<<"6,9,10,12,14,15,16,20:"<<endl; cin>>inc; ////////////////////////////////////////////////////////////////////// switch(inc) {
case 6: { cout<<"YOU HAVE SELECTED A 6 INCH CONVEYOR FOR WHICH FROM
GRAPH"; n=c*6.66*0.1; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 9: { cout<<"YOU HAVE SELECTED A 9 INCH CONVEYOR FOR WHICH FROM
GRAPH"; n=c*1.75*0.1; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 10: { cout<<"YOU HAVE SELECTED A 10 INCH CONVEYOR FOR WHICH
FROM GRAPH"; n=c*1.25*0.1; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 12: { cout<<"YOU HAVE SELECTED A 12 INCH CONVEYOR FOR WHICH
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Design & Fabrication of Screw Conveyor
FROM GRAPH"; n=c*0.08; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 14: { cout<<"YOU HAVE SELECTED A 14 INCH CONVEYOR FOR WHICH
FROM GRAPH"; n=c*14/30; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 15: { cout<<"YOU HAVE SELECTED A 15 INCH CONVEYOR FOR WHICH
FROM GRAPH"; n=c/30; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 16: { cout<<"YOU HAVE SELECTED A 16 INCH CONVEYOR FOR WHICH
FROM GRAPH"; n=c/45; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; }
case 20: { cout<<"YOU HAVE SELECTED A 20 INCH CONVEYOR FOR WHICH
FROM GRAPH"; n=c*0.017; cout<<",FOR THE GIVEN CAPACITY , THE VALUE OF RPM IS:"<<n; cout<<endl; break; } default: { cout<<"YOU HAVE NOT SELECTED A STANDARD VALUE "<<endl; break; }
} cout<<endl; /////////////////////////////////////// cout<<"MATERIAL CLASS MEANS FOLLOWING:"<<endl; cout<<"A-VERY FINE ,100MESH:"<<endl; cout<<"2-FREE FLOWING ANGLE:"<<endl; cout<<"7-MILD ABRASIVE:"<<endl; cout<<"Y-AERATED AND BECOMES FLUID:"<<endl;
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Design & Fabrication of Screw Conveyor
d2=25.5*inc;//CONVERTING INCHES INTO MM cout<<"SCREW DIAMETER="<<d2<<endl; cout<<"MODIFY THE SCREW DIAMETER TO STANDAED VALUE
WHICH IS EQUAL TO PITCH"<<endl;for(j=0;j<12;j++){cout<<stdpitch[j]<<endl;}cout<<endl;cout<<"SO ,GIVE THE STANDARD VALUE WHICH YOU HAVE
SELECTED NOW (FROM TABLE):"<<endl;cin>>p;
///////////////////////////////////////////////////////// cout<<"CALCULATING THE DIAMETER OF HOLLOW SHAFT WHICH IS
LOCATED AT THE CENTER:"<<endl;
cout<<"*************************************************************************"<<endl; cout<<"c=3.142/4*(d2*d2-d1*d1)*p*k*BD*RPM*60"<<endl; x=((d2*d2)/(1000*1000))-((4*c)/(3.142*p*0.001*0.3*1.0404*n*60)); d1=sqrt(x); d1=d1*25.5; cout<<"HOLLOW SHAFT OUTSIDE DIAMETER="<<d1; cout<<endl; cout<<"'k'IS 0.3 FOR 30%LOADING "<<endl; cout<<endl; cout<<"'d1' IS SHAFT DIAMETER"<<endl; cout<<endl; cout<<"'BD' is BULK DENSITY"<<endl; cout<<endl; cout<<"WE SELECT AN ELECTRIC RESISTANCE
WELDED(E.R.W.)PIPE"<<endl; cout<<"TYPE :'C' CLASS BECAUSE IT HAS MORE THICKNESS,WHICH
WILL AVOID BENDING"<<endl; cout<<"SELECT STD VALUE OF THE PIPE O.D. WITH THE HELP OF
cout<<"#######################################################"<<endl; cout<<endl; cout<<"NOW , GIVE THE VALUE OF STANDARD PIPE O.D. FROM ABOVE
TABLE:"; cin>>y/1000; cout<<endl; d1=y; cout<<"SELECT THE STANDARD WALL THICKNESS FROM THE
TABLE:"; cout<<endl;
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Design & Fabrication of Screw Conveyor
cin>>t; pid=d1-2*t; cout<<"PIPE INSIDE DIAMETER IS"<<pid; cout<<endl; l=2*p+cd; cout<<"CONVEYOR OVERALL LENGTH WOULD BE ="<<l; cout<<endl; /////////////////////////////////// cout<<"ESTIMATING THE HORSE-POWER REQUIRED:"<<endl; cout<<"***********************************"<<endl; cout<<"IN ORDER TO CALCULATE THE POWER REQUIRED WE SHALL
ASSUME 100% LOADING"<<endl; c1=3.142/4*(d2*d2-d1*d1)*0.125*l*n*60; cout<<"CAPACITY AT 100% LOADING ="<<c1; cout<<endl; cout<<"CONVERTING INTO LBS/HOUR"<<endl; c1=c1*2205; cout<<"SO,THE VALUE OF CAPACITY IN LBS/HOUR IS ="<<c1; cout<<endl; cout<<"H.P. =l*(c1*F)/100000"<<endl; cout<<"'l' IS THE LENGTH OF CONVEYOR IN FEET"<<endl; cout<<"'f' IS THE H.P. FACTOR=1 FOR PORTLAND CEMENT"<<endl; cdf=0.003268*cd;//cross section distance in feet hp=(cdf*c1*f)/100000; cout<<"H.P. IS ="<<hp; bhp=hp/0.75; cout<<"REQUIRED MOTOR H.P. IS BHP="<<bhp; clrscr(); ///////////////////////////////// cout<<"MOTOR SELECTION"; cout<<endl; cout<<"***************"; cout<<endl; cout<<"FOLLOWING TABLE SHOWS STANDARD HP,FRAME SIZE
cin>>n1; rr=n1/n; cout<<endl<<"REDUCTION RATIO IS ="<<rr; cout<<endl; cout<<"WE USE THE GEAR BOX TO REDUCE THE SPEED FROM "<<n1; cout<<" RPM TO "<<n; cout<<" RPM "; cout<<endl;
getch(); /////////////////////// cout<<"FLIGHT SELECTION"<<endl; cout<<"****************"<<endl; cout<<"FLIGHT IS MADE FROM A HOLLOW DISC WHICH IS RADIALLY
CUT AND PULLED TO FORM A FLIGHT"<<endl; cout<<"SEVERA SUCH FLIGHT ARE BUTT WELDED TO FORM THE
COMPLETE SCREW"<<endl; cout<<"THE PROPORTIONS FOR THIS HOLLOW DISC ARE AS FOLLOW
:"<<endl; did1=(d1*d1*3.142+0.125*p)/3.142; did=did1^(1/2); cout<<"DISC INSIDE DIAMETER="<<did; cout<<endl; cout<<"CONSTANT =SCREW DIAMETER+PIPE O.D."<<endl; c2=d1+d2; cout<<endl; cout<<"CONSTANT="<<c2; dod=c2+did; cout<<endl; cout<<"DISC OUTSIDE DIAMETER="<<dod; cout<<endl; n2=1000/p; cout<<"NUMBER OF FLIGHTS="<<n2; cout<<endl; cout<<"WE TAKE ONE HANDED FLIGHT"<<endl; cout<<"THEREFORE NUMBER OF RIGHT HANDED FLIGHT="<<(n2-1); cout<<"THICKNESS OF FLIGHT :2 TO 5 MM"<<endl; cout<<"MATERIAL OF FLIGHT IS MILD STEEL"<<endl; /*getch();*/
/////////////////////////////// cout<<"TROUGH SELECTION:"<<endl; cout<<"*****************"<<endl; cout<<"WE SELECT A FLANGED TROUGH."<<endl; cout<<"THE TOP FLANGES ARE FORMED INTEGRALLY FROM A SINGLE
STEEL SHEET."<<endl; cout<<"WE SELECT SQUARE INLET AND OUTLET POINTS ON THE
clrscr(); cout<<"ENTER THE SCREW DIAMETER SELECTED IN INCHES(in betwee 1 to 50) :"<<endl; cin>>sd1; cout<<"ENTER THE STANDARD SHAFT DIAMETER SELECTED IN mm :"<<endl; cin>>od; cout<<"ENTER THE STANDARD THICKNESS IN mm :"<<endl; cin>>t; sd= (sd1* 25.5)/4; initgraph(&gd,&gm,"C:\\TC\\bgi"); setbkcolor(BLACK);
TRIAL 1ENTER THE CAPACITY DESIRED IN TPH:2.654ASSUMING CENTER TO CENTER DISTANCE =1000 MM:SELECT THE SCREW DIA FROM FOLLOWING STD SIZES6,9,10,12,14,15,16,20:6YOU HAVE SELECTED A 6 INCH CONVEYOR FOR WHICH FROM GRAPH, FORTHE GIVEN CAPACITY,THE VALUE OF RPM IS: 59.938156
MATERIAL CLASS MEANS FOLLOWING:A-VERY FINE, 100MESH2-FREE FLOWING ANGLE7-MILD ABRASIVEY- AERATES AND BECOMES FLUIDSCREW DIAMETER = 153MODIFY THE SCREW DIAMETER TO THE STANDARD VALUE, WHICH ARE GIVEN BELOW.100125160200250315355400450500560630SO, GIVE THE STANDARD VALUE WHICH YOU HAVE SELECTED NOW:160CALCULATING THE DIA. OF HOLLOW SHAFT WHICH IS LOCATED AT THE CENTRE:*************************************************************************c=3.142/4*(d2*d2-dl*dl)*p*k*BD*RPM*60ENTER THE PITCHNORMALLY FOR DIA < 400 MM DIA = PITCH125HOLLOW SHAFT O.D.=38.97863'k' IS 0.3 FOR 30 % LOADING'dl' IS SHAFT DIA.'BD'IS THE BULK DENSITY
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Design & Fabrication of Screw Conveyor
WE SELECT AN ELECTRIC RESISTANCE WELDED (E.R.W.) PIPETYPE. 'C'CLASS BECAUSE IT HAS MORE THICKNESS, WHICH WILL AVOIDBENDINGSELECT STD VALUE OF THE PIPE O.D. WITH THE HELP OF FOLLOWINGTABLE:PIPE O.D. * THICKNESS#############################################33.7 * 2.542.4 * 2.548.3 * 3.560.3 * 476.1 * 588.9 * 5114.3 * 5.5139.7 * 6152.4 * 7############################################
NOW, GIVE THE VALUE OF STANDARD PIPE O.D. FROM ABOVE TABLE:
NOW, GIVE THE VALUE OF STANDARD PIPE O.D. FROM ABOVE TABLE:42.4
SELECT STANDARD WALL THICKNESS FROM THE TABLE:2.5
PIPE INSIDE DIAMETER IS37.400002CONVEYOR OVERALL LENGTH WOULD BE = 1250ESTIMATING THE HORSE POWER REQUIRED:************************************IN ORDER TO CALCULATE THE POWER REQUIRED WE SHALL ASSUME 100% LOADINGCAPACITY AT 100% LOADING = 8.404825e+09CONVERTING INTO LBS/HOUR SO,THE VALUE OF CAPACITY IN LBS/HOUR IS = 1.853264e+13H.P.=l*(cl*F)/l00000‘1’IS THE LENGTH OF CONVEYOR IN FEET‘f’ IS THE H.P FACTOR =l FOR PORTLAND CEMENT
MOTOR SELECTION***************FOLLOWING TABLE SHOWS STANDARD HP,FRAME SIZE & RATED RPM OFMOTORSFRAME HP RATED RPM#############################56 0.125 132056 0.16 1340
56FRAME SIZE SELECTED = 56ENTER THE SELECTED RPM:1340REDUCTION RATIO IS = 22WE USE THE GEAR BOX TO REDUCE THE SPEED FROM 1340 RPM TO59.938156 RPM
FLIGHT SELECTION******************FLIGHT IS MADE FROM A HOLLOW DISC WHICH IS RADIALLY CUT ANDPULLED TO FORM A FLIGHTSEVERAL SUCH FLIGHTS ARE BUTT WELDED TO FORM THE COMPLETESCREW.THE PROPORTIONS FOR THIS HOLLOW DISC ARE AS FOLLOWS:DISC I.D. = 103CONSTANT-SCREW DIA+PIPE O.D.CONSTANT = 202.399994DISC O.D. = 305.399994NUMBER OF FLIGHTS = 8WE TAKE ONE HANDED FLIGHTTHEREFORE NUMBER OF RIGHT HANDED FLIGHTS = 7THICKNESS OFFLIGHTS: 2 TO 5 MMMATERIAL OF FLIGHT IS M.S.
TROUGH SELECTION:*******************WE SELECT A FLANGED TROUGH.THE TOP FLANGES ARE FORMED INTEGRALLY FROM A SINGLE STEEL SHEET.WE SELECT SQUARE INLET & OUTLET POINTS ON THE TROUGH.BEARING SELECTION:*****************
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Design & Fabrication of Screw Conveyor
DEPENDING UPON THE END SHAFT DIAMETER 'SKF' BEARINGS MAY BE SELECTED.UNTILL THIS WE HAVE BEEN DISCUSSING THE DESIGN.NOW WE SWITCH ON TO THE GRAPHICS FUNCTION WHICH WILL GIVE US THE VIEW OF THE CONVEYOR.ENTER THE SCREW DIA SELECTED IN INCHES:6ENTER THE STANDARD SHAFT DIA SELECTED IN MM:42.4ENTER THE STANDARD THICKNES IN MM:2.5
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Design & Fabrication of Screw Conveyor
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Design & Fabrication of Screw Conveyor
TABLE NO. 1
MATERIAL CLASS DESCRIPTION
Size Material characteristics ClassVery fine – 100 mesh and under
Fine – ½ inch mesh and under
Granular – ½ inch and under
Lumpy – containing lumps over ½ inch
Irregular – being fibrous, stringy, or the like
A
B
C
D
HFlowability Very free flowing – angle of repose up to 30º