screw conveyor(Kaple)

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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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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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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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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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BUCKET ELEVATORS

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Centrifugal dischargeelevator

Positive dischargebucket elevator


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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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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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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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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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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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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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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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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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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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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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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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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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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.

C=3.142/4*[(D*D)-(d*d)]*p*k*r.p.m*60

C=3.142/4*[((0.160*0.160)-(0.04)*( 0.04))*0.125*1* 60*60

C=8.48 TPH

Converting it into lbs per hour

C=8.48 *2205

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=18703.472 LBS PER HOUR

Now H.P. = L*[(D*S+Q+F)]/1,000,000 where,

L=c/c length of conveyor in feet

D = Bearing factor

Q = Capacity in lbs per hour

F = Horse power factor (F = I for cement Portland)

S = Conveyor speed in r.p.m.

H.P. = 2.459 * 18713 * 1 / 1,000,000

H.P. = 0.046

Since the length of conveyor c/c is one meter therefore no hanger bearing is required and

hanger bearing factor, D =0

Brake horse power (B.H.P)

B.H.P. = H.P. * P

The value of p for H.P. less than one is 2

B.H.P. = 0.046*2

= 0.092

Actual B.H.P. = 0.092 / efficiency of gear wheel

= 0.092/0.85

= 0.108

= 0.125 (Standard value)

= Required motor H.P

3.3 SELECTION OF MOTOR

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As seen in catalogue of Hindustan Electric Motors we select a 4 - pole

motor.

The Frame size is 71 for 0.5 H.P. Motor as seen from table no. 3 Looking

in motor dimensions for frame 71 we get the input diameter of motor " d " =9mm. As seen

from table no. 4

Motor rating 0.125H.P/1380 r.p.m.

We have got motor r.p.m. = 1380 and required speed =60 r.p.m (max)

Therefore reduction ratio is 1380/60 =23 = 25 (approx)

We reduce the speed from 1380 r.p.m to 60 r.p.m or lesser in two stages.

We use a gearbox.

3.4 SELCETION OF GEAR BOX

We take a reduction ratio of 25:1

Therefore output of gear box = 1380 /25 = 55.2 r.p.m.

Motor h.p. = 0.125

Multiplying motor h .p by service factor i.e. 1.5

We get h.p. = 0.1875

Taking h .p. = 0.23

The catalogue for selection of gearbox is shown in table no: 5

We select the size of gearbox unit as 112 based on the reduction ratio required 25/1

3.5 SELECTION OF COUPLING

Screw conveyors are limited in overall length by the amount of torque that

can be safety transmitted through the coupling.

Thus we calculate torque to be transmitted and select the coupling on the

basis of this torque.

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Torque T = 716* motor h. p *service factor / motor rpm

=716*0.25 *l.5/1320

= 0.203 kg-cm.

We select a "LOVEJOY" coupling from table no: 7

Having the following specifications:

COUPLING TYPE - L

COUPLING SIZE -050

The selected coupling should fit on the shafts of motor and gearbox.

The dimensions of type -L love joy flexible coupling are as given in the table no: 8

For coupling size-L 050 we get,

MATERIAL - CAST IRON (C 1)

MINIMUM BORE = 5mm.

MAXIMUM BORE = 16mm.

Now, motor shaft diameter = 9mm

And, Therefore coupling is acceptable.

3.6 FLIGHTS

CONVEYOR SCREW FLIGHTING

Screw conveyor flighting is made in either of two ways, as helicoids or

sectional flights. Helicoids flights are formed from a flat bar or strip into a continuous

helix. This flighting is thinner on the outer edge then on the inner edge. This process

provides a continuous one piece construction with a work hardened, smooth finished

flighting surface. Sectional flights are formed from a flat disc and the thickness of the

flight is uniform. The lead of a sectional flight is slightly greater then one pitch. A joining

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a number of sectional flights together on a piece of pipe and butt-welding them together

make continuous helix.

LEFT HAND RIGHT HAND

"RIGHT HAND AND LEFT SCREWS"

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A conveyor is a right hand or left hand as determined by how the helical

flighting is formed .The hand of the screw may be clearly and easily ascertained by looking

at the end of the screw, as shown in the fig 4.6.

The screw pictured to the left has the helical flighting wrapped around the

pipe in a counter- clockwise direction. This is arbitrarily termed a Left- hand screw.

The screw pictured to the right has the helical flighting wrapped around the

pipe in a clockwise direction. This is termed a RIGHT hands screw.

A conveyor screw viewed from either end will show the same

configuration. If the end of the conveyor screw is not readily visible, then by merely

imaging that the flighting has been cut and the cut end exposed, the hand of the screw

readily may be determined.

The arrows in the Fig. 4.7 indicate which way the material will move if

right or left hand screws are rotated as indicated.

It will be obvious to the attentive observer that the HAND of conveyor

screw is a most important consideration in the design, application and ordering of a

conveyor screw. Once a screw conveyor is built and installed with a certain hand,

direction of the rotation is fixed for the desire direction of material transport. Any

replacements must be of the same HAND to avoid disastrous results.

If the hand of the screw isn't specified, the screw manufacture will normally

supply a RIGHT HAND screw.

We select sectional flights with both RIGHT HAND and LEFT HAND

flights on a single screw.

"CALCULATIONS"

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The screw shaft with the profile of the helix of flight and is development is

as shown in figure

After development we get a right-angled triangle.

The disc internal diameter calculated is a internal diameter of flat disc

from which a section flight is to be formed.

Therefore we get,

Disc I. D * 3.142 = [(PIPE O. D* 3.142) 2] 1/2

= [(42.5* 3.142) 2+(125) 2] 1/2

= 182.84

DISK INTERNAL DIAMETER = 58.2

= 60 mm

DISC OUTER DIAMETER = DISC INTERNAL DIAMETER + CONSTANT

CONSTANT = Screw diameter + pipe outer diameter

= 125 + 42.5

= 167.5

= 168

DISC OUTER DIAMETER = 167.5 + 58.2

= 225.7

= 226

This disc internal diameter 60mm and outer diameter 226mm will be cut

radically and then bent in the form of flight over the pipe. This flight section will be butt-

welded to form the complete screw. Now over all

conveyor length = 1m + 2 * pitch

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=750+2 * 125

= l000 mm.

No. of flights = 1000/125

= 8 flights

We take five right handed flights from inlet end of trough to outlet, and one

left handed flight from the end plate of trough at outlet side to discharge.

Thickness of flight = 3.25mm.

Material = Mild steel (ms).

TROUGHS

The trough not only confines and guides the flow of material, but also

serves as the housing in which all operating components are supported and held together in

there proper functional relational ship.

Corrosive or high temperature applications may require the specific

qualities that make stainless steel and non-ferrous metals well adapted to this service. In

general, any type of troughs that can be fabricated of mild steel also be made of stainless or

aluminum, brass, bronze, copper, monumental, nickel, etc.

FLANDED TROUGH

By forming the top flanges integrally with the trough sides from a single

steel sheet, ad equal strength and rigidity is obtained without super fulvous bulk or wait.

ANGLE FLANGED TROUGH

This trough is identical in construction to the flanged trough; accept that top

flanges are obtained by securely welding structural steel angles to the troughs.

RECTANGULAR TROUGH:

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Rectangular trough may be made from a single steel sheet or with sides and

bottom of separate pieces, dependent on size and gauge of metal .It is frequently used to

handle abrasive materials capable of forming a layer of material on the bottom of the

trough. The material thus move on it's self, protecting the trough from undo wear.

We select single flanged trough.

TROUGH COVERS

The functions of trough cover are

(1) The personal are not protected by the Inaccessible location of moving parts of a

conveyor, to protect personal from contact with the rotating screw and

(2) To keep the conveyed material and dust within the conveyor housing, and to exclude

foreign materials there from. The degree to which the cover feeds the trough depends

upon circumstances attending the particular conveying problem and so thus the means

of securing the cover.

Since our project is for demonstration purpose we use a transparent acrylic

trough cover so that the different components are usually visible for better understanding

and fitted to the trough with the help of bolts.

We provide clearance of 3 mm bet-screw flight and trough.

Therefore radius = screw diameter /2+3=62.5+3=65.5mm

We select trough end thickness= 3m

We take a clearance of 25mm between trough cover plates and screw flight.

Therefore depth=25=screw diameter

Trough thickness = clearance.

= 25 +125 + 3 + 3 = 156mm

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Normally the trough cover plate is of 5.8mm thickness material mild steel.

Based on experience the spacing between the boards provided on troughs is 150mm.

"INLET AND OULET"

We select square inlet and outlet points.

Normally the dimensions of this square is,

= Pitch +2 *clearance

= 125 +2 *3 = 131mm.

The inlet and outlet centers are at a distance of 0.75m and are pitch distance

away from respective ends.

3.7 SCREW CONVEYORS END THRUST

Most screw conveyor can be design with little thought given t


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area over the screw at the inlet. For short conveyor it is not significant but for the long

conveyor it is not significant but for long conveyors it is usually not advisable to have the

screw section in compression, as at every connection there could be a side force that would

tend to cock the connection of the coupling to the pipe.

The most common dives in use today are so called screw conveyor drives

that are adaptation of shaft mounted reduces. This includes drive shafts that are secured in

the reducer so to take thrust in either direction and transfer the thrust force to one of the

hollow shaft bearings of the reducer.

Usually when selecting the end bearing for screw conveyor that has a large

amount of thrust it may be necessary to consider the overhung load in using a roller chain

device.

3.8 CONVEYOR SCREW DEFLECTION

Deflections of conveyor screw of standard length are not usually a problem.

However, if longer than standard sections of screw are to be used, without intermediate

hangers bearings, care should be taken to prevent the screw flights from contacting the

trough because of excessive deflection.

Very often using a conveyor screw section with the large diameter pipe can

solve a problem.

3.9 SELECTION OF END- SHAFT AND BEARING.

BEARING SELECTION

Bearing are deep grove ball bearing 2 bearings of dia.20mm are selected i.e.

2 bearings of SKF6204 are selected based on shaft dia. = 20mm & checked as follows:

Assuming life required =10,000hrs.

C.O.E. & T.,Akola31


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Assuming 90% probability of survival.

Life in million revolution = L*60*N/1000000

= 10,000*60*52.5/100000

= 31.5mR

Bearing load for one bearing P = (x*Fr+Y*Fa) S

Neglecting 'Fa' as there is no axial load coming on to bearing theoretically. Therefore, P =

x*Fr*S

= 1*140*1.2 (Fr=Ra=Rb)

= 168N

= 16.8kg.

Assuming 50% overloading P~25kg

Dynamic capacity C = (L10)*P

= (31.5)*25

=78.95

~80kg.

Bearing of SKF6204 are selected be reducing shaft dia from 37mm 20mm.

For deep groove ball bearing SKF6204

Dynamic capacity =1000kgf (from psg 4.13)

& Max permissible in rpm= 1600rpm(from psg 4.13)

In our case dynamic capacity =80kgf & Rpm-52.5

Therefore bearing is very well safe.

CHECK THE DESIGN

C.O.E. & T.,Akola32


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Adding l& 2

Total udl. on 1 m length =l11 N/m

Taking 50% overload to be on safe side

udl=1.5*111=166.5N/m.

Load fluctuations may come due to dynamic loading

Therefore further increasing udl.

Say udl =200N/m.

3) Load due to each solid shaft

a. Shaft of dia 20mm

W3 = volume* density

= [3.142*(0.020)*(0.020)*0.075]*7800

= 0.184kg.

= 2 Newton. (Approx)

Assuming load acts on bearing

b. Shaft of diameter 57mm

W4 = 3.142[(0.037)*(0.037)*0.050]*7800

= 0.41kg = 5N.

Taking more load for safer design

Let, load due to shaft of dia 20mm be 5N & load due to shaft of dia 20mm be 10N.

4) Load due to hollow pipe (udl)

w5 = volume * density

= [(do*do-di*di)*length]*7800

= [(0.0424*0.0424-0.037*0.037)*l]*7800

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= 2.6266 kg.

Taking 60% overload to be on safer side.

W5 = 5kg.(approx)

Considering this also as a udl of 50 Newton/ meter

Total UDL = 200 + 50 = 250 Newton/meter

Distance of the center from LH bearing = 0.525

Therefore, maximum bending moment.

M = 140*0.525-10*(0.525-0.05)-[((0.525-0.025)^2)/2)*10

M = 67.5 Nm.

M = [3142/32*(d2^4 dl^4)d211 *fs

67500 = [3.142/32 (42.4^4 37^4)/42.4]*fs

fs = 21.47 N/mm^2

The value of shear stress is less than 50N/mm^2

HENCE THE DESIGN IS SAFE.

FINDING THE DEFLECTION OF HOLLOW PIPE

Taking only hollow beam & span 1m (approx.)

Deflection = (5*W*L^4)/(384*E*I)

Deflection = (5*0.25*1000^4)/(384*2.1*100000*66.65*1000)

Deflection = 0 232573 mm

This is quite low deflection, hence tolerable.

HENCE THE DESIGN IS SAFE.

C.O.E. & T.,Akola35


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INSTALLATON OPERATION AND

MAINTAINANCE

4.1 GENERAL

Because of variations in length and installation conditions, screw conveyors

are usually complete units, shop assembled and match marked before shipping, or as

individual components to be aligned and assembled in the field. When the manufacturer

engineers the conveyor, complete specification drawings are generally famished.

Manufacturers instructions should be followed.

SAFETY

Conveyor assemblies or components must be installed and operated in such

a manner as to comply with the occasional safety and health act, all state and local

regulations, and the Indian standard institute safety code.

4.2 GENRAL SAFETY PRECAUTIONS

Taking in to consideration all of the physical aspects of the installation, any

or all of the following safeguards may be required to protect the operators and those

working in the immediate area of the conveyor.

1. COVERS AND GRATINGS use rugged gratings in all open loadings areas and the solid

covers in other areas. Covers guards gratings at the inlet points must be such that the

screws cannot injure personnel.

2. LOCKOUT AND TAG-OUT. A formalized lock-out or tag-out procedure must be

followed when a conveyor is stopped for maintenance or repairs and before conveyors or

guards are removed .all safety devices, conveyors and guards shall be replaced before

starting equipment for normal operation.

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3.GUARDS. For protection of the operator and other persons in the working area,

purchaser should provide guards for all exposed equipment such as drives, gears, shafts,

couplings.

NOTE : DO NOT STEP OR WALK ON CONVEYOR COVERS OR GRATING OR

POWER TRANSMISSION GUARDS.

4.3 PRECAUTION FOR HAZARDOUS OPERATIONS

Standard screws conveyors are not equipped to operate; under conditions

are not equipped to operate under conditions, which may be hazardous, nor with hazardous

materials. The manufacturer should be consulted if there is any indication that a hazardous

condition or material is involved. Several situations may create these conditions. A few of

the more common follow:

Hazardous conditions

Where the product area is under pressure or vacuum, or the trough is

provided with jackets for heating or cooling, special precautions are required. Standard

components are not designed for this service.

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Hazardous materials

These may be explosive, flammable, toxic, noxious, etc. special provisions

for safety are required -Do not use standard components.

4.4 ELECTRICAL

Conveyor components manufacturers generally do not provide electrical

equipment to control the conveyors. In the conveyor installation, the purchaser must used

with any conveyor installation, the purchaser must use equipment confirming to the

national electrical code, and the other local or national codes.

All devices such as those listed below are intended the safety and/or overall

performance of the equipment. Consideration must be given to their use as secondary

safety devices as they might present a false sense of security to the operator or other

personnel safety precaution around the equipment .in no case are they intended to replace

or reduce the importance of lock-Out and Tag-out procedures, the primary.

1. Overload protection. Devices such as shear pins, torque limiters, etc to shut off power

whenever operation of conveyor is stopped as result of excessive material, foreign

objects, excessively large pumps, etc.

2. No-speed protection. Devices such as zero speed switches to shut off power in the

event of any incident that might cause conveyor to cease operating.

3. safety shut off switch with power lockout provision at conveyor drive.

4. emergency stop switches readily accessible wherever required.

5. electrical interlocking to shut down feeding conveyors whenever a receiving

conveyor stops.

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6. signal devices to warn personnel of imminent start up of conveyor, especially if started

from a remote location.

7. special enclosures for, motors and controls, in hazardous atmospheric conditions.

4.5 INSTALLATION

1. All assemblies and parts are checked against the bill of materials.

2. place the screw inside the trough .Fix the trough end plates with bolts provided . A thin

lining of rubber is placed between the trough and it's end plates. Do not tighten the

bolts. Align trough bottom and centerline, and then tighten the bolts.

3. now assemble bearings inside the Plummer blocks

4. installing stuffing box on the screw shaft.

5. slide the Plummer block on the screw shaft and rest it on the base plate using bolts.

Ensure that the Plummer block slides smoothly over the plate.

6. fix the handle on the screw shaft.

7. place the acrylic cover on the trough and fix it using bolts.

4.6 OPERATION

Only persons familiar with the following precautions should be permitted to

operate the conveyor. The operator should thoroughly understand these instructions before

attempting to use the conveyor.

WARNING

Guards, access doors, and covers must be securely fastened before operating

this equipment. Lock out power before removing guards, access doors and covers. Failure

to follow these instructions may result in personal injury or Property damage.

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1. Always operate the conveyor in the accordance with these instructions.

2. Do not place hands or feet in the conveyor opening.

3. Never walk on conveyor covers or gratings.

4. Do not put conveyor to any other use than for which it is designed.

5. Avoid poking or prodding material in the conveyor with bar or stick inserted through

openings.

6. Always have a clear view of conveyor loading and unloading points and all safety

devices.

7. Keep area around conveyor drive and control free of debris and obstacles.

8. NEVER operate conveyor without covers, grating, guards and other safety devices in

position.

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INITIAL STARTUP (WITHOUT MATERIAL)

1. REMEMBER - Screw conveyor drive is generally shipped without oil. Add oil to drive

in accordance with manufacturers instructions.

2. MAKE SURE before initial start-up that conveyor is empty, that end bearings and

lubricated, and that all cover guards, safety equipments are properly installed.

3. If conveyor is part of a material handling system, make certain that conveyor controls

are interlocked electrically with those for other units in system.

4. Check direction of rotation of each unit to assure correct flow of material.

5. Operate conveyor while empty for several hours, making a continuous check for

heating of bearings, misalignment of drive, and noisy operation, if any of these occur

proceed as follows:

a. If anti-friction bearings are used, check supply of lubricant. Either too much or too less

lubricant can cause high operating temperatures.

b. Lock out power supply and check for misalignment in trough ends, screws and

hangers. Loosen and readjust or shim as necessary. If unable to eliminate

misalignment, check parts for possible damage during shipment.

c. Check assembly & mounting bolts.

INITIAL STARTUP (WITH MATERIALS)

1. Check that the conveyor discharge is clear before feeding material.

2. Increase feed rate gradually until rated capacity is reached.

3. Stop & start conveyor several times & allow to operate for several hours.

4. Shut off conveyor and lock out power supply. Remove covers and check coupling bolts

for tightness. Check hanger bearings, realign if necessary and retighten mounting bolts.

5. Replace covers.

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EXTENDED SHUT DOWN

If conveyor is to be inoperative for a long period of time, it is advisable to

permit it to operate for a period of time after the feed has been cutoff in order to discharge

as much as possible from the trough. However there is a nominal clearance of 1/2

"between the screw & trough and this procedure will allow amount of material to remain in

the trough. Therefore if the material is corrosive or hygroscopic or has a tendency to

harden or setup, the trough should be cleaned completely after the4 conveyor is shut down

and power locked out.

4.7 MAINTENANCE

Establish routine period inspection of the entire conveyer to insure

continuous maximum operating performance. Keep the area around the conveyor drive

clean and free of obstacle to provide easy access and to avoid interference with the

function of the conveyor or drive.

1. lock out power to motor before doing any maintenance work preferably with a padlock

on control.

2. Do not remove padlock from control nor operate conveyor until covers and guards are

securely in place.

SERVICING OF CONVEYOR COMPONENTS

In most cases this involves removing an unserviceable part and installing a

replacement. The installation procedures are outlined in the section entitled ERECTION.

Specific instructions for the removal of various conveyer components follows.

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CONVENTIONAL CONVEYOR SCREWS

To remove a section or sections of conventional conveyor screw from end

opposite the drive. Remove trough end, conveyor screw sections, coupling shafts, and

hangers until damaged or worn section is removed.

To reassemble, follow above steps in reverse order.

Sections of conventional conveyor screw equipped with slights flight

couplings may be removed individually with a minimum of disturbance of adjacent

sections.

COUPLINGS

Replace couplings when wear exceeds 1/8 inch. Replace coupling bolts

when excessive wear causes play.

LUBRICATION

Frequency of lubrication will depend on factors such as the nature of

application, bearing materials and operating conditions. Weekly inspection and lubrication

is advisable until sufficient experience permits establishment of a longer interval.

DRIVE.

Lubricate the drive following manufacturers instructions provided for the

speed for the speed reducer and other drive components requiring lubrication speed

reducers are generally shipped without oil.

BALL OR ROLLER BEARINGS.

Ball and roller bearings may be furnished in trough ends. Lubricate in

accordance with manufactures instructions provided.

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CONCLUSION

This project titled "DESIGN AND FABRICATION OF A SCREW

CONVEYOR " explains the design and manufacturing of a screw conveyor, basic

application of which is to transport cement for a distance of one meter horizontally.

This project gives detailed information about the various factors that me

taken into account before designing and selecting different components, which form a part

of screw conveyor, it also gives the details of be assembly as per the standard procedure

employed in the industry.

Moving ahead from designing stage this project gives a detailed count of

the fabrication of the screw conveyor, its installation and its maintenance for a better

performance and a longer life.

Finally the project highlights the major advantages of the screw conveyor

and its superiority over other conveyor designs.

C.O.E. & T.,Akola44


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BIBLIOGRAPHY

1. Link Belt - Screw conveyor & screw feeder

FMC Corporation - Material Handling Equipment division

MISSISSIPPI-38801

2. Stephen-Adamson

Material Handling Equipment Division, Chicago.

3. American Society of Mechanical Engg.

3. Material Handling Hand Book.

4. www.theshathigears.com

5. www.rediff.com

6. www.google.com

7. www.howstuffworks.com

8. www.altavista.com

C.O.E. & T.,Akola45
http://www.theshathigears.com/http://www.rediff.com/http://www.google.com/http://www.howstuffworks.com/http://www.theshathigears.com/http://www.rediff.com/http://www.google.com/http://www.howstuffworks.com/


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The Proposed Estimation of Our Project is as follows

Particulars Qty Amount

1) Screw pipe, Flight 01 1075.00

2) Shaft (in 2 parts) 02 0200.00

3) Bearings 02 0175.00

4) Hub 02 0100.00

5) Cover plate, Side plate 02 0200.00

6) Trough 01 0225.00

7) Coupling 02 0300.00

8) Reduction Gear Box 01 2475.00

Total 4750.00

C.O.E. & T.,Akola46


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APPENDIX

This gives a program in C++, which calculates the various proportions for the screw conveyor for

the given input capacity desired. The program also gives the assembly of screw conveyor in pictorial view.

//THIS PROGRAMME GIVES THE DESIGN OF A SCREW CONVEYOR AND

//GIVES ITS VARIOUS PROPORTIONS WITH SCEMATIC DIAGRAM.

# include

#include

#include

#include

#include#include

void draw();

void design();

void start();

void main()

{

start();

design();draw();

}

void start()

{

int gd=DETECT,gm;

initgraph(&gd,&gm,"C:\\TC\\bgi");

setbkcolor(BLACK);setcolor(2);

settextstyle(7,HORIZ_DIR,3);

outtextxy(180,20,"WELCOME TO PROJECT");outtextxy(280,50,"OF");

outtextxy(0,80," DESIGN AND FABRICATION OF SCREW CONVEYOR");


outtextxy(30,240," ....SUBMITTED BY....");

outtextxy(30,260,"1)SHASHANK KAPLE");

outtextxy(30,280,"2)ANANT NAGNE");

outtextxy(30,300,"3)RAKESH RODE");

outtextxy(30,320,"4)SHAHID FAIYAZ");outtextxy(30,340,"5)VINOD JAYLE");

outtextxy(30,360,"6)DEBASIS BARUA");outtextxy(200,180,"*GUIDED BY....");

outtextxy(220,200,"PROF. P.R. WADNERKAR");

outtextxy(200,140,"*H.O.D.....");

outtextxy(220,160,"PROF. C.V. DESHMUKH");

outtextxy(0,380,"***********************************************************************

");outtextxy(0,220,"***********************************************************************

");

outtextxy(0,120,"***********************************************************************

");

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outtextxy(0,10,"************************************************************************");

outtextxy(5,400,"PRESS ENTER


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FROM GRAPH";

n=c*0.08;

cout


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d2=25.5*inc;//CONVERTING INCHES INTO MM

cout


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cin>>t;

pid=d1-2*t;

cout


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cout


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54/68


rectangle(x+531-12,midy+(sd+12+15),x+531-112,midy+(sd+12+17));

setlinestyle(2,1,1);line(x+32+17,midy-(sd+43),x+32+17,midy-(sd+29));

line(x+32+107,midy-(sd+43),x+32+107,midy-(sd+29));line(x+32+17,midy-(sd+26),x+32+17,midy-(sd+11));

line(x+32+107,midy-(sd+26),x+32+107,midy-(sd+11));

line(x+531-17,midy+(sd+8),x+531-17,midy+(sd+20));

line(x+531-107,midy+(sd+8),x+531-107,midy+(sd+20));

line(x+531-17,midy+(sd+22),x+531-17,midy+(sd+34));line(x+531-107,midy+(sd+22),x+531-107,midy+(sd+34));

id=(od-4*t)/4;

od=od/4;

rectangle(x+531,midy-id,x+506,midy+id);

rectangle(x+39,midy-id,x+64,midy+id);

line(x+64,midy-id,x+506,midy-id);

line(x+64,midy+id,x+506,midy+id);line(x+38,midy-od,x+531,midy-od);line(x+38,midy+od,x+531,midy+od);

rectangle(x+32,midy-13,x+24,midy-5);

rectangle(x+32,midy+13,x+24,midy+5);

line(x+32,midy-13,x+24,midy-5);

line(x+24,midy-13,x+32,midy-5);

line(x+32,midy+13,x+24,midy+5);


rectangle(x+546,midy-13,x+538,midy-5);rectangle(x+546,midy+13,x+538,midy+5);

line(x+546,midy-13,x+538,midy-5);line(x+538,midy-13,x+546,midy-5);



line(x+532-62,midy+sd,x+532-62,midy+(sd+35));

line(x+532-62,midy-(sd+37+35),x+532-62,midy-(sd+37+20));

line (x+532-62,midy-(sd+37+20),x+532-62,midy-(sd+37+15));line(x+532-62,midy-(sd+37+15),x+532-62,midy-(sd+37));

line(x+532-62,midy-(sd+37),x+532-62,midy-(sd+37-5));

line(x+532-62,midy-(sd+37-5),x+532-62,midy-(sd+37-20));

line(x+532-62,midy-(sd+37-20),x+532-62,midy-(sd+37-35));

line(x+32+62,midy-(sd+37+35),x+32+62,midy-sd);

i=sd/3;

line(x+38,midy-od,x+38+i,midy-sd);

line(x+38+i,midy-sd,x+38+4*i,midy+sd);

l=4;

for(i=sd/3;k5)

{

setcolor(0);setfillstyle(0,1);

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fillellipse(580,midy,4,4);

fillellipse(587,midy,4,4);

fillellipse(592,midy,4,4);fillellipse(595,midy-26,20,20);

fillellipse(592,midy+25,15,19);fillellipse(595,midy+51,20,20);

fillellipse(615,midy+50,35,35);

}

setcolor(WHITE);

if(sd1==10)

line(x+38+22*i,midy+sd,x+531,midy+od);if(sd1==8)

line(x+38+28*i,midy+sd,x+531,midy+od);

arc(x+2,midy-2,90,270,3);

arc(x,midy+2,90,360,3);

arc(x+568,midy-2,270,90,3);

arc(x+571,midy+2,90,360,3);

setlinestyle(0,1,1);rectangle(x+12,midy-21,x+32,midy-5);rectangle(x+12,midy+21,x+32,midy+5);

rectangle(x+538,midy-21,x+558,midy-5);rectangle(x+538,midy+21,x+558,midy+5);

setcolor(2);


outtextxy(120,20,"ASSEMBLY OF SCREW CONVEYOR");

line(x+39,midy+(sd+22+35),x+531,midy+(sd+22+35));

line(x+39,midy+(sd+22+30),x+39,midy+(sd+22+40));

line(x+531,midy+(sd+22+30),x+531,midy+(sd+22+38));settextstyle(2,HORIZ_DIR,4);

outtextxy(x+40,midy+(sd+22+29),"");

line(x-25,midy-sd,x+38+i,midy-sd);

line(x-25,midy+sd,x+38+4*i,midy+sd);

line(x-15,midy-sd,x-15,midy+sd);

line(x+32+62,midy-(sd+37+15),x+531-62,midy-(sd+37+15));

settextstyle(2,HORIZ_DIR,5);outtextxy(x+230,midy+(sd+60),"OVERALL LENGTH");

outtextxy(x+250,midy+(sd+40),"1000 mm");

outtextxy(x+200,midy-(sd+70),"CENTRE TO CENTRE LENGTH");

outtextxy(x+250,midy-(sd+50),"750 mm");

outtextxy(x+32+68,midy-(sd+37+23),"");

settextstyle(2,VERT_DIR,4);

outtextxy(x-35,midy-30,"SCREW DIA.");

sprintf(sdc," %3.2f mm ",4*sd);

outtextxy(x-15,midy-30,sdc);getch();

closegraph();

}

C.O.E. & T.,Akola55


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WE SELECT AN ELECTRIC RESISTANCE WELDED (E.R.W.) PIPE

TYPE. 'C'CLASS BECAUSE IT HAS MORE THICKNESS, WHICH WILL AVOID

BENDING

SELECT STD VALUE OF THE PIPE O.D. WITH THE HELP OF FOLLOWINGTABLE:

PIPE O.D. * THICKNESS

#############################################33.7 * 2.5

42.4 * 2.5

48.3 * 3.560.3 * 4

76.1 * 5

88.9 * 5

114.3 * 5.5

139.7 * 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 = 1250

ESTIMATING THE HORSE POWER REQUIRED:

************************************IN ORDER TO CALCULATE THE POWER REQUIRED WE SHALL ASSUME 100%

LOADING

CAPACITY AT 100% LOADING = 8.404825e+09CONVERTING INTO LBS/HOUR

SO,THE VALUE OF CAPACITY IN LBS/HOUR IS = 1.853264e+13

H.P.=l*(cl*F)/l00000

1IS THE LENGTH OF CONVEYOR IN FEETf IS THE H.P FACTOR =l FOR PORTLAND CEMENT

MOTOR SELECTION***************

FOLLOWING TABLE SHOWS STANDARD HP,FRAME SIZE & RATED RPM OF

MOTORSFRAME HP RATED RPM

#############################

56 0.125 132056 0.16 1340

C.O.E. & T.,Akola57


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63 0.25 1350

71 0.33 1370

71 0.5 1380

80 0.75 140080 1 1400

90S 1.5 1410

112M 5 1440132S 7.5 1440

132M 10 1450

160M 15 1450160M 20 1455

##################################

SELECT STANDARD FRAME SIZE FROM ABOVE TABLE:

56FRAME SIZE SELECTED = 56

ENTER THE SELECTED RPM:1340

REDUCTION RATIO IS = 22

WE 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 AND

PULLED TO FORM A FLIGHTSEVERAL SUCH FLIGHTS ARE BUTT WELDED TO FORM THE COMPLETE

SCREW.

THE PROPORTIONS FOR THIS HOLLOW DISC ARE AS FOLLOWS:DISC I.D. = 103

CONSTANT-SCREW DIA+PIPE O.D.

CONSTANT = 202.399994DISC O.D. = 305.399994NUMBER OF FLIGHTS = 8

WE TAKE ONE HANDED FLIGHT

THEREFORE NUMBER OF RIGHT HANDED FLIGHTS = 7THICKNESS OF

FLIGHTS: 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 STEELSHEET.

WE SELECT SQUARE INLET & OUTLET POINTS ON THE TROUGH.

BEARING SELECTION:*****************

C.O.E. & T.,Akola58


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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 USTHE VIEW OF THE CONVEYOR.

ENTER THE SCREW DIA SELECTED IN INCHES:

6ENTER THE STANDARD SHAFT DIA SELECTED IN MM:

42.4

ENTER THE STANDARD THICKNES IN MM:2.5

C.O.E. & T.,Akola59


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C.O.E. & T.,Akola60


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TABLE NO. 1

MATERIAL CLASS DESCRIPTION

Size Material characteristics Class

Very fine 100 mesh and under

Fine inch mesh and under

Granular inch and under

Lumpy containing lumps over inch

Irregular being fibrous, stringy, or the like

A

B

C

D

H

Flowability Very free flowing angle of repose up to 30

Free flowing angle of repose 30 to 45

Sluggish angle of repose 45 and up

1

2

3

Abrasiveness Nonabrasive

Mildly abrasive

Very abrasive

6

7

8

Other

characteristics

Contaminable, affecting use or saleability

Hygroscopic

Highly corrosive

Mildly corrosive

Gives off dust or flames harmful to life

Contains explosive dust

Degradable, affecting use or saleability

Very light and fluffy

Interlocks or mols to resist digging

Aerates and becomes fluid

Packs under pressure

K

L

N

P

R

S

T

W

X

Y

Z

TABLE 2

C.O.E. & T.,Akola61


62/68


C.O.E. & T.,Akola62


63/68


C.O.E. & T.,Akola63


64/68


C.O.E. & T.,Akola64


65/68


C.O.E. & T.,Akola65


66/68


C.O.E. & T.,Akola66


67/68


C.O.E. & T.,Akola67


68/68


Documents

screw conveyor(Kaple)