fabrictaion of mechanical seed thresher for farm

7/24/2019 Fabrictaion of Mechanical Seed Thresher for Farm

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PROJECT TITLE

A PROJECT REPORT

Submitted to

SUNRISE UNIVERSITY

in partial fulfilment for the award of the diploma of

POLYTECHNIC

In

MECHANICAL ENGINEERING

DEPARTMENT OF MECHANICAL ENGINEERING

SUNRISE UNIVERSITYALWAR

RAJASTHAN, INDIA

MAY 2014

Annexure1

PROJECT TITLE

A PROJECT REPORT


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Submitted toSUNRISE UNIVERSITY


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CERTIFICATE

This is to certify that the project report entitled TITLE OF PROJECT WORK

submitted by NAME OF GROUP to the SunRise University Alwar,Rajasthan in partial

fulfilment for the award of Diploma of Polytechnic in Mechanical Engineeringis a confide

record of the project work carried out by him under my supervision during the year 2015-

2016.

Submitted to: Submitted by:

Name of incharge Name of student(Roll)

Designation

Name (Project Guide)Designation

SUNRISE UNIVERSITYBagad Rajput, ALWAR-301030(Raj.)

INDIA


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ACKNOWLEDGEMENT

I take this opportunity to express my profound gratitude and deep to my mentor Mr.

Vinayak Hemadri for his exemplary guidance, monitoring and constant encouragement

throughout the course of this thesis. The blessing, help and guidance given by him time to

time shall carry me a long way on the journey of life in which I am about to embark. I also

take this opportunity to express a deep sense of gratitude to the mentor for his cordial

support, valuable information and guidance, which helped me in completing this task through

various stages.

Lastly, I thank almighty, my parents, and friends for their constant encouragement

without which this assignment would not be completed.


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ABSTRACT

Rice is one of the chief grains in India, and as such, is a major food crop, especially in

the Eastern and Southern regions of India. Rice production accounts for a sizable amount of

the economy. However, farmers that lack resources continue to harvest the same using

traditional methods, which affect their yield, thereby affecting their earnings.

We propose to build a semi-automated paddy thresher that will help farmers improve

efficiency during threshing. It will also lower grain damage and reduce labor needed for

threshing. We also hope to lower power consumption and provide a mechanism for speed

control. We sincerely believe that the improved design can help enrich the lives of farmers

across the nation.


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TABLE OF CONTENTS

CHAPTER NO TITLE PAGE NO

ABSTRACT 5

LIST OF FIGURES 6

LIST OF TABLES 8

CHAPTER 1

1.1 INTRODUCTION 11

1.1.0 METHODS OF THRESHING 11

1.1.1 FLAIL 11

1.1.2 THRESHING FLOOR 11

1.1.3 PEDAL OPERATED PADDY THRESHER 11

1.1.4 THRESHING MACHINE/COMBINE HARVESTERS 12

1.2 CLASSIFICATION OF THRESHERS 13

1.2.1 FEED-IN TYPE THRESHERS 13

1.2.2 HOLD-ON TYPE THRESHERS 14

1.3 PROPOSED PADDY THRESHER 14

1.3.1 AUTOMATED MOTOR 14

1.3.2 VIBRATING MESH 15


CHAPTER 2

2.1 BLOCK DIAGRAM 20

2.2 LITERATURE SURVEY 20


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2.1.0 MAIN COMPONENTS OF PADDY THRESHER 21

2.2.1 FRAME 21

2.2.2 THRESHING DRUM 21

2.2.3 THRESHING TEETH 21

2.3OPTIMIZATION

2.3.1 INCREASING OUTPUT EFFICIENCY 21

2.3.2 PORTABILITY AND EASE OF USE 22

2.3.3 POWER SOURCE 22

2.4 SAFETY AND COST 22

CHAPTER 3

3.1 DESIGN 23

3.2 MATERIAL SELECTION 23

3.3 PROCESS OF FABRICATION 23

3.3.1 BUILDING THE FRAME 23

3.3.2 FABRICATING THE THRESHING DRUM 23

3.3.3 ATTACHING THE MOTOR 24


3.3.5 FABRICATING THE HOOD 24

3.4 MECHANISM FOR VIBRATING MESH 24

CHAPTER 4

4.1 AUTOMATION 26

4.1 SINGLE PHASE INDUCTION MOTOR 26

4.1.1 CONSTRUCTION 26

4.1.2 WORKING PRINCIPLE 27


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4.1.3 COMPARISON BETWEEN SINGLE `

PHASE AND THREE PHASE INDUCTION MOTOR 29

4.2 SPEED CONTROL 29

CHAPTER 5

5.1 PROPOSED DESIGN SEED THRESHER 31

5.2 PROPOSED DESIGN FAN ALIGNMENT

DISC CLOCKWISE ROTATION AND

ANTI-CLOCKWISE ROTATION FOR THRESHER 32

5.3 PROPOSED DESIGN POWER SUPPLY

UNIT FOR THE WORKING OF ALL THE

THREE MOTORS AT A SAME TIME. 33

5.4 PROPOSED DESIGN POSITION OF THE

FAN IN WHICH THE CLOCKWISE AND ANTI-CLOCKWISE

ROTATION IS DEPENDED UPON THIS PRPOSED POSITION. 34

5. 5 HARDWARE USED IN PROJECT 35

5.6 TOOLS USED IN PROJECT 35

5.7 ESTIMATION OF THE PROJECT WORK 37

CHAPTER 6

CONCLUSION AND SCOPE FOR THE FUTURE

6.1 IMPLEMENTED METHODS 38

6.2 FUTURE SCOPE 38

6.2.1 SPEED CONTROL 38

6.2.2 FULLY AUTOMATIC PADDY THRESHER 38


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CHAPTER 7

CONCLUSION 39

REFRENCES 40


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LIST OF FIGURES

FIGURE.NO NAME PAGE.NO

1.1 Seed Thresher 12

1.2.2.1 Feed-In Type 14

2.1.1 Seed Thresher Unit 20

5.1 Proposed Design Seed Thresher

5.2 Proposed Design Fan Alignment Disc Clockwise Rotation

and Anti-Clockwise

Rotation For Thresher 31

5.3 Proposed Design Power Supply

Unit For The Working Of All The

Three Motors At A Same Time. 32

5.4 Proposed Design Position Of The Fan

In Which The Clockwise And Anti-Clockwise

Rotation Is Depended Upon This Proposed 33


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CHAPTER 1

INTRODUCTION

There are many steps involved in the process of getting the rice from the fields and

into our homes. First the rice stalks must be harvested from the fields. The next step of the

process is threshing. It is the process of separation of the grain from the stalk. This can be

done manually or by the action of a revolving mechanism. Grain damage is a potential

problem faced during threshing.

1.1 Methods of threshing

Several methods of threshing exist. Some continue to be used today, while others

have evolved with advancements in technology. A brief description of these methods is listed

below.

1.1.1 Flail

It is a hand held agricultural tool which is used to separate grain from the stalk. It is a

labour intensive and time consuming process. The flail is used to beat grains on a threshing

floor. The grains are later collected from the floor.

1.1.2 Threshing Floor

The stalks are spread across the threshing floor and animals like bulls or donkeys

walk round and round dragging a threshing board to separate the grain from the stalk.

1.1.3 Pedal operated paddy thresher

The idea was developed in Japan and is still popular with poor farmers in many parts

of the world. It consists of loop type threshing drum with a supporting frame. It improves

efficiency and is less labour intensive. However there are instances of injury to hands and

arm while feeding the stalks into the thresher.


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Fig 1.1: Seed Thresher

1.1.4 Threshing Machine/Combine Harvesters

Industrialization helped remove much of the drudgery from the process of farm labor.

The threshing machine uses the same principle as the above. Earlier they were hand-fed and

horse powered but now they can be completely automated. Modern day combine harvesters

use the same basic principles but are much larger in size.

The first threshing methods involved beating grain by hand with a flail, or trampling it by

animal hooves. An early threshing machine, patented in 1837 by Hiram A. and John A. Pitts,

Winthrop, Maine, was powered by horses walking on a treadmill. Improvements were made

to the original machine until late in the 1800s. The threshing machines used early in the 20th

century were basically the same, except for the power source. About 1890, steam engines

replaced horses and mules, and around 1915, tractors with diesel, kerosene or gasoline

became more prevalent. In the early 1920s, combines a combination harvester and

thresher made their debut, but they did not replace threshing machines completely until

about the middle of the century.

A threshing machine is used to separate the grain from the straw and other light materials. It

is, essentially, a three-step process:


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In the first stage, bundles of grain and straw were pitched into the feeder (or hopper). The

feeder controlled the rate of feed passing into the machine to prevent overloading. In reality,

the rate at which the bundles were pitched into the hopper probably had more effect on the

rate than the hopper itself.

In the second stage, the separator, a rapidly rotating set of blades (visible at the end of the

feeder), first tore the bundles apart, breaking the twine and snapping the heads from the

straw, then beat the straw and heads onto a grooved plate, knocking kernels from the heads

without crushing them. The straw then passed over a straw rack that removed most of the

straw from the kernels. Whatever passed through fell onto a series of progressively smaller

shaking screens, removing most of the remaining straw and chaff from the kernels.

In the third stage, the cleaner, kernels that passed through the last screen were moved over a

stream of air that blew the remaining straw and chaff away. The cleaned kernels then fell into

a hopper to be elevated to a measuring device before being dumped into sacks or conveyed to

a granary. The straw and chaff were blown out onto the straw stack by a larger, stronger

blower.

1.2 Classification of threshers

Threshers can be broadly classified into two categories on the basis of method of

feeding. Both categories come with their own set of advantages and disadvantages.

1.2.1 Feed-in type threshers

In these types of threshers, the whole crop is directly fed into the machine. It provides

higher throughput than hold-on type and allows the farmers freedom to move around. But

these types of threshers are prone to clogging with the straw. It also has higher power

requirement to drive the drum. Sometimes it also results in injuries to hands of the operator.


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1.3.2 Vibrating Mesh

Winnowing is the process of separation of grain from the chaff. We propose to use a

vibrating mesh to separate the paddy grains from the chaff after threshing. This can help

reduce time spend in winnowing and requires no extra effort from the farmers side.


Winnowing is the process of separation of grain from the chaff. We propose to use a

vibrating mesh to separate the paddy grains from the chaff after threshing. This can help

reduce time spend in winnowing and requires no extra effort from the farmers side.

Modern day combine harvesters (or simplycombines)operate on the same principles and use

the same components as the original threshing machines built in the 19th century. Combines

also perform the reaping operation at the same time. The name combineis derived from the

fact that the two steps are combined in a single machine. Also, most modern combines are

self-powered (usually by a diesel engine) and self-propelled, although tractor powered, pull

type combines models were offered by John Deere and Case International into the 1990s.

Today, as in the 19th century, the threshing begins with a cylinder and concave. The cylinder

has sharp serrated bars, and rotates at high speed (about 500 RPM), so that the bars beat

against the grain. The concave is curved to match the curve of the cylinder, and serves to hold

the grain as it is beaten. The beating releases the grain from the straw and chaff.

Whilst the majority of the grain falls through the concave, the straw is carried by a set of

"walkers" to the rear of the machine, allowing any grain and chaff still in the straw to fall

below. Below the straw walkers, a fan blows a stream of air across the grain, removing dust

and fines and blowing them away.
https://en.wikipedia.org/wiki/Combine_harvesterhttps://en.wikipedia.org/wiki/Combine_harvester


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The grain, either coming through the concave or the walkers, meets a set of sieves mounted

on an assembly called a shoe, which is shaken mechanically. The top sieve has larger

openings, and serves to remove large pieces of chaff from the grain. The lower sieve

separates clean grain, which falls through, from incompletely threshed pieces. The

incompletely threshed grain is returned to the cylinder by means of a system of conveyors,

where the process repeats.



















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blower.

Some threshing machines were equipped with a bagger, which invariably held two bags, one

being filled, and the other being replaced with an empty. A worker called a sewerremoved

and replaced the bags, and sewed full bags shut with a needle and thread. Other threshing

machines would discharge grain from a conveyor, for bagging by hand. Combines are

equipped with a grain tank, which accumulates grain for deposit in a truck or wagon.

A large amount of chaff and straw would accumulate around a threshing machine, and

several innovations, such as the air chaffer, were developed to deal with this. Combines

generally chop and disperse straw as they move through the field, though the chopping is

disabled when the straw is to be baled, and chaff collectors are sometimes used to prevent the

dispersal of weed seed throughout a field.

Thecorn sheller was almost identical in design, with slight modifications to deal with the

larger kernel size and presence of cobs. Modern-day combines can be adjusted to work with

any grain crop, and many unusual seed crops.
https://en.wikipedia.org/wiki/Corn_shellerhttps://en.wikipedia.org/wiki/Corn_sheller


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Both the older and modern machines require a good deal of skill to operate. The concave

clearance, cylinder speed, fan velocity, sieve sizes, and feeding rate must be adjusted for crop

conditions





















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blower.


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CHAPTER 2

2.1 BLOCK DIAGRAM

Fig 2.1.1: Seed Thresher Unit

2.2 Literature Survey

There are numerous types of paddy threshers available in the market. Each design has some

advantages and some disadvantages. We have identified the following focus areas for the

literature survey:

Main components of paddy thresher

Optimization of components

Power Source

Safety and Cost


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2.1 Main components of paddy thresher

The thresher consists of three main components frame, threshing drum and threshing teeth

2.2.1 Frame

The body frame of the thresher should be made of a durable materials like cast iron or mild

steel to increase life of the machine. The height of the frame should be comfortable for the

user, so that he/she should not have to bend. The recommended height is around 105 cm. 2.1

2.2.2 Threshing drum

The drum should be durable enough to take the load of the stalks. It should be constructed out

of slats which are supported at each end by cylinder end discs. The length of the drum should

not exceed 40 cm in case of single user.

2.2.3 Threshing teeth

The slats carry the threshing teeth. They should be arranged in linear manner with a distance

of 4 cm. The height of the teeth should not exceed 6.5 cm. The shape of the teeth affects grain

damage. To minimize damage to paddy grains, wire loop type teeth are preferred.

2.3OPTIMIZATION

Optimization is the methodology of selecting the best element with regard to some criteria.

We wish to optimize the thresher for small farmers.

2.3.1 Increasing output efficiency

Output efficiency of the thresher depends mainly upon the feed rate and the speed of the

drum. The feed rate of the thresher must not be too high so as to prevent overloading the

drum. The speed of the drum should not exceed 850 rpm so as to prevent grain damage.


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2.3.2 Portability and Ease of Use

Farmers prefer threshing machines which are portable as they can be used in any part of their

field. The thresher should be easy to operate as most farmers are not well versed with the

usage of highly technical machines.

2.3.3 Power Source

Pedal powered threshers require a lot of human labour. To automate the threshing

mechanism, one can use an electric motor or a diesel motor. Diesel motors, however, have

very high carbon emission and pose a threat to the environment.

Owing to the rising cost of diesel, electric motors are cheaper to run than diesel motors. Many

farmers have subsidized electricity rates and single phase supplies. An induction motor

requires a single phase supply and does not require much maintenance. An induction motor

of 0.5 hp would be sufficient to power the drum.

2.4 SAFETY AND COST

In agricultural related injuries, accidents due to threshers are the second most common.

Exposed rotating parts result in crushing or amputation of upper limbs. Hence, chute design is

an important parameter to prevent injuries. The chute opening height should be at least 32

cm. Elbows should be kept away to prevent injuries. Targeting small farmers, the goal of the

project is to offer a viably safe thresher at an affordable price. Also, the thresher should not

require much maintenance.


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CHAPTER 3

3.1 Design

The optimal dimensions have been summarized in the literature survey. The design,

however, involves more than a few technical specifications. In this chapter, we will cover the

actual dimensions that were used to build our thresher as well as the materials that were

selected for each component.

3.2 Material Selection

According to Indian standards of paddy threshers, cast iron and mild steel are the

recommended materials to build paddy threshers. For our project, we chose cast iron for

many purposes, most important being its competitive price. Cast iron can therefore do the

same job at a lower price. It is also easily available and has high tensile strength. The only

problem with cast iron is that is more prone to corrosion as compared to mild steel, but this

can be rectified with a paint job. For the base of the machine, we have used a 6 cm thick

panel of wood so as to provide cushioning and stability to the machine.

3.3 Process of Fabrication

The process of fabrication follows the sub-points mentioned below in their exact order:

3.3.1 Building the Frame

This is the first step in the process of fabrication. The frame was built using L-shaped bars

made of cast iron. The dimensions used for the frame are as specified in Section 3.1.

3.3.2 Fabricating the Threshing Drum

The drum was constructed using a series of slats, supported by a cylinder-end plate. Each slat

is 0.5 cm thick and 5 cm wide. The distance between two neighbouring slats is maintained at

Zmm. The cylinder-end plates have a thickness of 0.2 cm and are used to support the slats.

The threshing teeth are welded to the surface of the slat. We have selected Wire Loop type of

teeth which have been welded at a distance of 4 cm to each other.


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3.3.3 Attaching the Motor

We have used a Flat Belt type pulley system to attach the motor to the shaft of the drum. This

is the driving force of the machine. The pulley system also helps reduce the speed of the

motor.


The vibrating mesh is used to separate the grain from the chaff. We have used a linkage

assembly which converts the rotational motion of the drum into linear motion of the mesh.

3.3.5 Fabricating the Hood

This is the final step in the process of fabrication. A metal sheet is bent and welded to the top

of the thresher in order to prevent injury as well as preventing the grains from getting

scattered.

3.4 Mechanism for Vibrating Mesh

We make use of the rotator motion of the drum for the reciprocating motion of the mesh. A

Slider-crank can be used to convert circular motion into reciprocating motion.

This thresher is used to damage free threshing of seeds out of small quantities of plants

(umbels, cliques or pods). The machine is very suitable for breeding stations or processing

stock seed productions. The machine is equipped with an automatic air cleaning program and

dust suction connections. The plants are manually feed via an inlet table inside the threshing

chamber (only the seed pods). The plants will be broken into smaller pieces inside the

threshing chamber, by means of a rotor with three beaters which rotates in a threshing basket.

The seeds are threshed out. By means of a discharge valve at the front side of the machine the

straw can be discharged.

When the seeds pass the threshing basket they will be processed on a shaking screen. This

shaking screen is equipped with an outlet and an overflow. The materials that exit the


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machine over the screen is waste and will be collected in an anti-static bin. The seeds will fall

through the screen and will enter a vibratory feeder that will feed the seeds uniformly into the

air separator. Here will lighter and heavier parts will be separated. "Good" heavy seeds will

leave the air separator at the front side and can be collected in a small bag.Threshing, screen

cleaning and air separation in one machine ,Automatic air cleaning, significant reduction in

cleaning hours,Direct packing in small bags. Different perforations threshing baskets and

screens available. Visual inspection due to several polycarbonate windows. Process status

indication


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CHAPTER 4

4.1 Automation

Automation is the process of using control systems to operate equipment, reducing or

removing human intervention. In this chapter, we will discuss the specifications of the

induction motor used, followed by the method used for controlling the speed of the drum.

4.1 Single Phase Induction Motor

The single phase induction motor is the heart of the paddy thresher machine. We have

explained the construction and working of induction motor.

4.1.1 Construction

It has mainly two parts namely rotor and stator. Stator: As its name indicates stator is a

stationary part of induction motor. A single phase ac supply is given to the stator of single

phase induction motor. Rotor: The rotor is a rotating part of induction motor. The rotor is

connected to the mechanical load through the shaft. The rotor in single phase induction motor

is of squirrel cage rotor type. The construction of single phase induction motor is almost

similar to the squirrel cage three phase motor except that in case of asynchronous motor the

stator have two windings instead of one as compare to the single stator winding in three

phases induction motor.

After years of experience in the field of agricultural machinery, Amisy has developed lots of

excellent agricultural products that enjoy great popularity. Rice/Wheat thresher is one of our

products with mature technology. Welcome to make your purchase. The rice/wheat thresher

is mainly used for shelling the wheat, rice, sorghum, barley, millet, etc. It is efficient and can

thresh rice and wheat throughly. Rice thresher has the features of compact structure, beautiful

shape and reliable operation. Featured by its high production rate, good threshing


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performance and few loss of grain etc., it is a good helper with farmers.

Thresher Features

1.Reliable Quality: The machine is highlighted with compact structure, scientific design and

superior quality. Besides, it is anti-acid, anti-rust, and moisture proofed. The assignments are

of good quality, each index has reached national specification.

2. Wide Application: It is mainly used for threshing various crops like rice, wheat, corn,

soybean, barley, sorghum and millet etc..

3. High Efficiency: This thresher has combined working with separate winnowing so that the

grain, wheat bran, wheat straw would be separated and cleared at one time. It can thresh

various crops in high efficiency, separate husks and remove dust from the production

mixture.

4. Cost-saving: The machine has the advantages of high removal rate and low breakage,

which would cut down the harvest time and save labor cost at the same time.

5. High Security: The motor control is equipped with over current, overload and short circuit

protection.6. Others: It owns advantages such as compact structure, easy operation, easy

maintenance and high efficiency etc..

4.1.2 Working Principle

When single phase ac supply is given to the stator winding of single phase induction motor,

the alternating current starts flowing through the stator or main winding. This alternating

current produces an alternating flux called main flux. This main flux also links with the rotor

conductors and hence cut the rotor conductors. According to the Faradays law of

electromagnetic induction, EMF gets induced in the rotor. As the rotor circuit is closed one

so, the current starts flowing in the rotor. This current is called the rotor current. This rotor

current produces its own flux called rotor flux. Since this flux is produced due to induction


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principle so, the motor working on this principle got its name as induction motor. Now there

are two fluxes one is main flux and another is called rotor flux. These two fluxes produce the

desired torque which is required by the motor to rotate.

Early threshing machines were hand-fed and horse-powered. They were small by today's

standards and were about the size of an uprightpiano.Later machines weresteam-powered,

driven by aportable engine ortraction engine.Isaiah Jennings, a skilled inventor, created a

small thresher that doesn't harm the straw in the process. In 1834, John Avery and Hiram

Abial Pitts devised significant improvements to a machine that automatically threshes and

separates grain from chaff, freeing farmers from a slow and laborious process.

The1881 Household Cyclopedia said of Meikle's machine:

"Since the invention of this machine, Mr. Meikle and others have progressively

introduced a variety of improvements, all tending to simplify the labour, and to

augment the quantity of the work performed. When first erected, though the grain was

equally well separated from the straw, yet as the whole of the straw, chaff, and grain,

was indiscriminately thrown into a confused heap, the work could only with propriety

be considered as half executed. By the addition of rakes, or shakers, and two pairs of

fanners, all driven by the same machinery, the different processes of thrashing,

shaking, andwinnowing are now all at once performed, and the grain immediately

prepared for the public market. When it is added, that the quantity of grain gained

from the superior powers of the machine is fully equal to a twentieth part of the crop,

and that, in some cases, the expense of thrashing and cleaning the grain is

considerably less than what was formerly paid for cleaning it alone, the immense

saving arising from the invention will at once be seen.
https://en.wikipedia.org/wiki/Pianohttps://en.wikipedia.org/wiki/Steam_enginehttps://en.wikipedia.org/wiki/Portable_enginehttps://en.wikipedia.org/wiki/Traction_enginehttps://en.wikipedia.org/wiki/Household_Cyclopediahttps://en.wikipedia.org/wiki/Winnowinghttps://en.wikipedia.org/wiki/Winnowinghttps://en.wikipedia.org/wiki/Household_Cyclopediahttps://en.wikipedia.org/wiki/Traction_enginehttps://en.wikipedia.org/wiki/Portable_enginehttps://en.wikipedia.org/wiki/Steam_enginehttps://en.wikipedia.org/wiki/Piano


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"The expense of horse labour, from the increased value of the animal and the charge

of his keeping, being an object of great importance, it is recommended that, upon all

sizable farms, that is to say, where two hundred acres [800,000 m], or upwards, of

grain are sown, the machine should be worked by wind, unless where local

circumstances afford the convenience of water. Where coals are plenty and cheap,

steam may be advantageously used for working the machine."

4.1.3 Comparison between Single phase and Three phase Induction Motor

1. Single phase induction motors are simple in construction, reliable and economical for

small power rating as compared to three phase induction motors.

2. The electrical power factor of single phase induction motors is low as compared to three

phase induction motors.

3. For same size, the single phase induction motors develop about 50% of the output as that

of three phase induction motors.

4. The starting torque is also low for asynchronous motors.

5. The efficiency of single phase induction motors is less as compare it to the three phase

induction motors.

4.2 Speed Control

We hope to control the speed of the single phase induction motor using triac and a 555 timer.

The control circuitry used depends on one parameter voltage. 13 Torque Developed in a

Motor Square of Voltage We control the voltage applied to the stator terminals of the

induction motor using gate pulses from the triac. Delaying of the pulses to the gate reduced

the voltage applied to the stator terminals of the induction motor, and as voltage and torque

are proportional to each other, a decrease in torque simultaneously decreases the speed of the

motor.


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The control circuit consists of the following:

Triggering Circuit

Triac Circuit

Power Supply Circuit

Power Supply Circuit provides a DC supply of 5 V and 12 V to devices requiring the biasing

voltage. The triggering circuit is used to generate pulses which are then given to the triac as

gate pulses. This acts as the trigger. The triac circuit acts as an intermediate between the

induction motor and the supply.


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CHAPTER 5

FABRICATION OF THE MECHANICAL SEED THRESHER FOR

FARM.

5.1 PROPOSED DESIGN SEED THRESHER


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5.2 PROPOSED DESIGN FAN ALIGNMENT DISC

CLOCKWISE ROTATION AND ANTI-CLOCKWISE

ROTATION FOR THRESHER

(Note: Only One Blade Is Painted In All Set Of Blades Because To Identify The

Rotation Of The Blade Either Clockwise Or Anti-Clockwise.)


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5.3 PROPOSED DESIGN POWER SUPPLY UNIT FOR THE

WORKING OF ALL THE THREE MOTORS AT A SAME TIME.

(Note: This Adapter Is To Give Power Form The Supply Board Automatically And This

Is Easy In Plugging And Un-Plugging The Unit. This Can Be Moved To Any Platform

Of Workspace.)


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5.4 PROPOSED DESIGN POSITION OF THE FAN IN WHICH THE

CLOCKWISE AND ANTI-CLOCKWISE ROTATION IS DEPENDED

UPON THIS PROPOSED POSITION.


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5. 5 HARDWARE USED IN PROJECT:

Fabricated Fan

Mounting Plate

Threaded Screw

Base Plate

Bearing

Coupling

Movable Joints

Steel Plates For Supporting

Welding Electrodes

Pitch Scale

Wires for Connection

Motor

Hardwares To Fit

Power Supply

Switch

5.6 TOOLS USED IN PROJECT:

Welding Machine

Screw driver

Spanner


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Soldering Rod

Soldering flux

Punching machine

Drilling Machine

Bench Vice

Axe Frame

Insulation Tape


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5.7 ESTIMATION OF THE PROJECT WORK:

HARDWARE WORK ESTIMATION OF COST

FABRICATION OF BLADES 1775

MOUNTED PLATE 275

CASTING OF BLADE 1000

POWER SUPPLY 250

MOTOR MOUNTING PLATE 175

WELDING WORKS 325

RIVETING OF BALDES 450

MOULDING OF FAN BLADES 400

DRILLING 450

MOTOR 450

CONNECTING WIRES 100

OTHER EXPENSES 350

TOTAL 6000


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CHAPTER 6

CONCLUSION AND SCOPE FOR THE FUTURE

There is scope for improvement in the level of automation of the paddy thresher.

Towards this, in conclusion, we will cover a summary of the methods weve used in our

system and propose a scope for what can be done in the future.

6.1 Implemented Methods

The paddy thresher was built with the aim of helping small farmers increase their

output, reducing labour required and providing a safe and standardized machine at an

affordable cost. The machine is optimized to ensure easy use for the farmer and is built with

safe guards to prevent accidents and injuries in a field with a high risk of amputation. Also,

the machine can

be used by a single farmer, as opposed to requiring multiple people operating a single

machine.

Another important aspect we considered was that our machine would test the tides of

time and reduce the cost of maintenance. The machine also combines the process of threshing

and winnowing, thereby reducing the work to be done by the farmer, as it has automatic grain

separation.

6.2 Future Scope

While we have mentioned that our machine is a semi-automatic one, there is scope for

increasing the level of automation in the thresher. A great way to do this is by implementing

speed control of the threshing drum. We will discuss a few points below:

6.2.1 Speed Control

The speed of the threshing drum should be lowered while changing the bundle of stalks. As

mentioned in Section 4.2, the speed of the threshing drum can be controlled using a triac and

a 555 timer. This can help lower the power consumption as well as the risk of injuries, which


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will supplement the goal we had in mind while building this machine. We believe that the

optimum speed we can reach using this method is 600 rpm.

6.2.2 Fully Automatic Paddy Thresher

The current design of the paddy thresher requires the farmer to hold the bundle of stalks over

the threshing drum. We propose to build a mechanism to hold these stalks in place and flip

them over after a certain period of time using a simple flipping mechanism. A

microcontroller can be used to trigger this flipping mechanism after a set period of time,

which can be programmed in the microcontroller.


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CHAPTER 7

CONCLUSION

What we have built is a product that can be used in the field today. However, while

we have identified the key areas that require change in a paddy thresher, we were unable to

implement everything that we had hoped to. Nonetheless, what we have built is a step in the

right direction and a little bit of improvement can render it as a viable solution to an

unaddressed problem faced by farmers for years.


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fabrictaion of mechanical seed thresher for farm

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