INTRODUCTION

Urea Deep Placement or UDP is the method of Deep placement (7-10 centimetres

below the soil surface) of urea briquettes, called Guti, near the roots of the rice plant

rather than spreading urea over the surface of the soil, which is the conventional

method. The Guti, which is the size of a mothball, slowly releases nitrogen

throughout the growing season. UDP are well-documented as superior nutrient

delivery systems compared with the traditional method of broadcasting urea. When

used to fertilize irrigated rice, briquettes are centred between 4 plants at a depth of

7-10 centimetres within 7 days after transplanting. Placement is conventionally done

either by hand or with a mechanical applicator. The results are: 1) Yields are

increased by 15-18 percent. 2) Fertilizer use is reduced by one-third. 3) Nitrogen

losses are reduced by 40 percent,

The technology allows for better absorption and efficiency of the fertilizer while

reducing runoff, and decreases the release of volatile greenhouse gas and

eliminates nitrification/ denitrification.

However, FDP technology is labour-intensive because fertilizer briquettes are hand-

placed near the root zone of rice plants. Further rising labor costs (close to $6 a day

during the season) makes the development of a mechanized & user friendly

applicator critical. This problem has delayed widespread farmer adoption. To

alleviate this issue, we developed a mechanical applicator for UDP.

The project includes designing and fabrication of the UDP applicator that performs

plunging of the urea briquettes at equal distances in the soil and that is easy to

operate and manoeuvre in paddy fields. The UDP applicator runs on a gasoline

powered engine and uses the Slider Crank Mechanism to Plunge urea briquettes

deep into the soil with fixed spacing.

With the help of UDP Applicator, the UDP technology can be successfully

implemented worldwide that would create huge impact on the agriculture around the

world increasing paddy productivity, reducing fertilizer consumption and

subsequently increasing GDP of paddy producing countries like India, Bangladesh

and Africa. Also, it will help reduce harmful emissions and help curb environmental

degradation.

The Urea Deep Placement Applicator or UDP Applicator is an automated version that

is run by a gasoline engine. A 197cc 3 HP Honda GK 200 Engine powers the

! 1

machine. The engine drives the plunging mechanism, picker mechanism as well as

the two lugged wheels through Chain Drives. The drive from the engine goes to the

gearbox via a friction clutch mounted on the crankshaft which can be disengaged to

disengage the mechanism. The gearbox is designed to provide the calculated speed

reduction to plunge urea briquettes at fixed distance. The gearbox transmits power to

the picker mechanism that has small buckets which picks-up urea briquettes from

the picker box and throws them in a pipe which delivers it under the plunger for it to

be plunged. The gearbox also transmits power to the crank of the slider-crank

plunger mechanism. The gear ratio of the picker and crank sprockets are such that

for every single rotation of the picker the crank will rotate 4 times since the picker

disc has 4 buckets on its periphery. The weight distribution of the machine

components is done to help the operator to manoeuvre it easily and such that it

balances itself in static as well as in dynamic conditions. It also has reduced risk of

toppling, even at high speeds. The wheels of the UDP Applicator have been selected

after several iterations. Two lugged wheels are used to propel the applicator in

forward direction and to provide sufficient friction or grip for the machine to prevent it

from slipping in the soil. The wheels can also provide movement to the machine on

concrete surfaces over short distances. A third Castor wheel that is located at the

back end of the machine performs three major functions: First, to give support to the

machine and keep it balanced, Secondly, the castor wheel helps in changing

direction of motion of the machine. It provides the advantage of Zero turning radius

to the machine, The machine pivots about any one of the lugged wheel and the

castor helps in turning the machine about the pivot with little effort. Lastly, the Castor

wheel acts as a furrow closing. That is, it covers the holes made by the plunger

during plunging operation by soil. The design of the UDP Applicator is shown below.

!

Fig. 1.0 design of udp applicator

! 2

LITERATURE REVIEW

1. Lupin M.S., Lazo J.R., N.D, et al, Briquetting, TP 963.4.U7B74

Results of tests by the International Fertilizer Development Center (IFDC) and

other organizations show that considerable improvement is achieved in the

agronomic efficiency of urea in wetland rice production by deep placement of

urea supergranules compared to broadcast application of urea prills. The

physical and chemical characteristics of urea make the material well suited for

production of urea supergranules by briquetting, which is an agglomeration

process using the application of pressure to powdered dry materials. Urea

briquettes of 0.8 to 2.0 grams produced by IFDC in a small briquetting

machine were of a good quality. Conceptual process designs were developed

for the manufacture of 1-to 2-gram urea briquettes considering different types

of urea feed material. The conceptual designs were used for developing cost

estimates for the production of uree briquettes. For briquetting plants added to

an existing urea complex, the estimated production cost premium for urea

briquettes is $14.5 to $20.3 per metric ton, depending upon plant capacity and

type of feed material. For a unit at a separate site, the estimated premium is

$36.8 per metric ton.

2. Khan A.U., Kiamco L., Tiangco V.,Fertilizer transfer to floodwater during deep

placement, IRPS No.96, Oct1983

This study indicates that presence of water during fertilizer placement plays a

major role in reducing fertilizer use efficiency in flooded rice fields. Fertilizer

applicators that have been developed in the past have transferred 40 to 70%

of the fertilizer to the floodwater during the placement operation.Five possible

ways of nitrogen transfer to floodwater are suggested. It was found that up to

40% of the placed fertilizer transfers to floodwater through dissolution during

transit froia the water surface to the furrow bottom. That was the major

avenue for fertilizer transfer.The second major transfer is when the fertilizer

solution and/or granules are pushed from the furrow bottom into the

floodwater as the furrow closes. Transfers due to nitrogen diffusion through

! 3

soil or through poorly closed furrows are not high. The authors argue that

minimizing nitrogen transfer to floodwater during fertilizer placement is the key

to improving fertilizer use efficiency in flooded rice fields. A deep placement

applicator concept for minimum transfer to floodwater is proposed. The paper

concludes that fertilizer dissolution and the dynamics of fertilizer solution in

flooded rice fields have not been fully understood and need further research

to improve fertilizer use efficiency.

! 4

PROBLEM FORMULATION AND METHODOLOGY

Stage 1: Prototype Designing

We started the design of the applicator with the intention to keep it simple, and

focused on easy fabrication, low cost, easy maintenance.

The applicator was designed keeping in mind the findings from the field visits to

Bangladesh & Ludhiana. It was clear that the machine needed to be able to run

between the planted rows of 20 cm width. We planned to make a machine with 2

powered front wheels and a single free rear wheel. The major challenge was to have

a machine with wheels distance as narrow as possible and yet be able to move

easily in deep wet mud. Also we did not want to increase the power requirement too

much and hence attempted this task with a low power input, as high power

requirement would significantly increase the operating costs and machine weight.

We identified the trans-planter and the power tiller as the 2 machines with similar

operating conditions as ours. Hence, we also studied them in great detail and

adopted certain aspects from their designs.

!

Fig 1.1 The first design

Inorder to provide mobility in wet soil without slipping we needed wheels that

provided sufficient traction and hence decided to have lugs attached. However, at

! 5

GearBox

Brique2ePicker

Engine

Wheel

Crank&Plunger

the same time, the wheels could not be allowed to sink too deep in the mud as this

would increase power requirement.

Another major design constraint we faced was that of machine width. We did not

want the side-powered lugged wheels to run over trans-planted paddy or previously

placed briquettes and dig them up. We thus decided that the powered wheels should

move in the rows adjacent to the one in which briquettes are being placed. The back

wheel would perform the furrow closing mechanism and cover the briquette

immediately after its placement therefore should be in the same row as the briquette

plunging mechanism.

Considering a plant row to row spacing of 6-8 inches, we had to maintain the spacing

between the front-powered wheels (inner to inner distance) to not more than 9

inches (with 3 inch wide wheels). We also decided to give an adjustability to the inter

wheel distance and provided an easy mechanism to do so for running the machine in

fields with greater crop spacing.

The narrow width would lead to instability of the machine: another cause of concern,

and to counter that we wanted to keep the center of gravity as low as possible to

ensure stability. However, the plunging mechanism’s requirements and ground

clearance needs meant that the crank’s center would have to be at a height of 70cm

above the bottom part of wheels. This height increase due to the plunging

mechanism has been a constant concern for us.

1.1 Power source –Gasoline Engine

Selecting the gasoline engine happened after weighing numerous pros and cons

versus diesel and battery options. The main reason for eliminating diesel was that of

weight increase. Diesel engines were much heavier and we could only find a

minimum weight of 44kg engine readily available in Delhi. The elimination of battery

was because of two reasons. Firstly, batteries are heavier, and secondly, they could

be riskier to use on wet paddy conditions. Hence, our choice for the first prototype

was a gasoline engine.

! 6

1.2 Gear Box

The engine & gearbox were both placed between the wheels. The plan was to

include the differential / clutch inside the gearbox at a later stage. Also the power

output for the crank would also be brought out from the same gearbox from the top.

1.3 Plunging Mechanism: Crank

Our earlier choice for plunging was a cam mechanism which would have ensured a

faster punching & return action during briquette placement. However, this

mechanism would have increased the complexity of the design and increased the

maintenance cost of the machine. We realized later that the crank would do the job

as well, while also not compromising on the cost and reparability aspects.

Stage 2: First Prototype Fabrication and Testing

2.1 Fabrication

Based on design above, we fabricated the first prototype in Ludhiana. To begin with

we decided to fabricate the frame, wheels, gear box and attach the engine to test

mobility and power of the machine.

2.2 Frame

It was decided to have the minimum inner to inner wheel distance as lesser than 9

inches. Hence, a width of 8 inches was fixed for the frame width between the wheels.

This provided sufficient design challenges throughout the process because

accommodating all the machine components between the wheels was always a

challenge.

2.3 Wheels

The powered-lugged wheels were 60cm in diameter fabricated on a 7mm thick bent

plate. The width of the wheels was 5inches. Each wheel contained 24 lugs and the

height of each lug was 3cm. The weight of a single wheel came to 15kg. The hub

and spokes had negligible weight as the spokes were made of hollow pipes, and

both the spokes and the hub had very less thickness.

! 7

2.4 Engine

The first design prototype of the UDP applicator was tried on a 1hp engine. The

engine was a light weight 6500rpm one. We designed a gearbox specific to its needs

and tried running the machine

2.5 Gear Box

Gear box was designed to bring down the engine rpm of 162 to wheel’s rpm of

40.The high speed of the engine increased the gear ratio and thus made the gear

box heavy.

! !

Fig 2.1 The 1hp engine Fig 2.2 Stage2 chassis – first prototype

! !

Fig 2.3 Gear box and engine assembly Fig 2.4 Power train assembly and

(stage 2) mounting

! 8

2.6 Testing

! !

Fig 2.5 Wheel dynamic testing Fig 2.6 Improved wheel design(with lugs)

During the initial days of fabrication, the frame was developed and tested in mud.

The testing was done on normal land and also on shallow wet mud. This brought out

a basic understanding of the difference in the power requirement in the two cases.

The testing was also done with the help of a spring balance to get an accurate

understanding of this difference. The test results were as below-

• (Power requirement in shallow wet soil) : (Power requirement in dry soil) = 3:1

• This ratio could significantly increase in deeper mud to the order of 10:1

2.7 Engine Issues

We soon realized the engine could move the machine but it did not have sufficient

power to overcome any obstacles that came in its way. The engine’s frame was very

delicate and we started facing problems immediately. The engine’s mounting point

broke and it became difficult to fit the engine without it. However, we managed by

slightly changing the mounting.

2.8 Gearbox smoothness issue

The high speed of rotation of the engine meant that we had to implement a high

gearbox reduction of 162. This made gearbox heavy and was not smooth in

operation.

2.9 Solution

The situation meant we had to hunt for a more suitable engine: higher power and

lower rpm. Hence, by the end of November 2012 we decided to move on to a more

powerful 3.5 hp 3750 rpm 70cc engine.

! 9

Table 2.1 Outline of stage 2

Criteria Aspect Details

Prototype Features Engine: Gasoline 1

Hp 6500 rpm

Diesel and battery options

discarded due to weight and

safety issues respectively

Frame Constraint: Width 8 inches,

as Paddy planted at 20 cm

separation so inner wheel

distance has to be less than

9 inches

Gear Box Gearbox reduction of 162 to

bring down engine rpm of

6500 to wheel rpm of 40

Wheels 2 Lugged Front Wheels: To

provide sufficient traction in

puddle fields

1 rear free wheel: To close

furrows and provide balance

& maneuverability

Drawbacks Engine: Insufficient

Power & Delicate

Gear Box: Heavy &

non smooth

Wheel: heavy

1 hp sufficient in dry land but

inadequate in wet land

High speed of engine

increased gear box weight

Proposed Solutions Replace Engine Replace 1 hp with 3.5 hp

engine of lower speed of

rotation

! 10

Stage 3 : Fabrication and Testing Prototype 2( Design with 3.5hp

engine)

!

Fig 3.1 Base design of stage 3 (prototype 2 – 3.5hp)

!

Fig 3.2 For comparing fabricated machine with base design

! 11

Gearbox

EngineFrontPoweredWheels

Brique2estorage

withpicker

Pipetoplace

brique2esbelow

plunger

Crank

ConnecJng

Rod

Plungertopunch

thebrique2esinto

thesoil

DifferenJal

3.1Fabrication

To overcome the challenges we faces in the initial design we began fabrication of the

3.5 hp engine powered prototype. And, once we achieved mobility in the machine we

thought of adding the picker & plunger mechanisms.

3.2Frame

The same basic frame used in the first prototype was used for the second prototype

too. There were additions on the frame later for adding crank, picker & plunger

mechanisms. And also minor changes on the frame were also made to for the engine

and gearbox mounting. The frame also required modifications when the briquette

container and picking mechanism had to shifted to reduce its speed (as shown in

images above, this is also described in the ‘Briquette Picking & Placement

Mechanism’ section).

!

Fig 3.3 Chassis – prototype 2

! !

Fig 3.4 Fabricated and assembled prototype 2 Fig 3.5 Dry Dynamic Testing

! 12

3.3 Engine & Gearbox

The new engine was selected with focus on weight, size, speed and power, and

hence selected a 3.5hp, 70ccengine that weighed 15kg (inclusive of an internal

gearbox that would help us reduce the weight of the external one). The engine came

with a kick start but we replaced that with long handle for starting the engine. The

kick start was not compatible with our machine design. In the eventual design we

could use a rope pulling mechanism to start the engine.

!

Fig 3.6 Design of prototype 2 explaining the relative position of the engine

and Gear box

Gearbox design

! !

Fg 3.7 Final design of the stage 3 gearbox Fig 3.8 Stage 3 gear box under

production

The gearbox design used for the 3.5hp engine is shown above. This gearbox

included a gear shifting mechanism to alter the speed of plunging / briquette

! 13

Gearbox

Engine

placement spacing. The new gearbox needed a much lesser gear ratio as the speed

of the 3.5hp engine reduced considerably over the previous 1 hp engine. Thus this

helped us reduce the weight of the new gearbox.

We also added the provision to change gears inside, using a lever, helping the

operator to change the speed of the plunger and hence vary the briquette spacing.

This would be useful for fields with varying crop distances. The gearbox was also

equipped with a neutral gear to stop the plunger movement completely.

With the 3.5hp engine, the engine & the gearbox were placed at a central location

between the front and the back wheels. The reason for this arrangement was that it

was not possible to fit the 3.5hp engine between the wheels (spaced 9 inches apart).

The gear sliding and lever mechanism inside the gear box (shown below) though

initially rough eventually smoothened out as we were able to fine tune the design.

! !

Fig 3.9Relative gear arrangement Fig 3.10 Assemble stage 3 gear box

of the stage 3 gear box with gear changing mechanism

3.4 Briquette Picking & Placement Mechanism

This mechanism comprises of a picker mechanism synchronized with the plunger

motion. The picker picks up one briquette during each briquette punching action of

the plunger. The picked urea briquette is then placed below the plunger through a

pipe. It is made to stop there by a rubber flap, until the plunger pushes the briquette

down into the soil with it during its downward stroke.

! 14

!

Fig 3.11 Stage 3 prototype explained

Plunger Mechanism Design

The initial design involved a crank fitted to a connecting rod through a pin. The

connecting rod on the other side was attached to the plunger. The joint was made at

the top of the plunger. This design was later changed and the connecting rod was

later attached to the side of the plunger. This improved the performance of the whole

mechanism.

!

Fig 3.12 Plunger mechanism under inspection

To increase smoothness of plunger movement the connecting rod’s length was

increased in order to reduce side forces on the plunger. This increase was

accompanied by a change in the height of the plunging mechanism & crank, in order

to maintain the plunging depth and ground clearance.

! 15

Crank

ConnecJng

Rod

Brique2estorage

withpicker

Pipetoplace

brique2esbelow

plunger

Plungertopunch

thebrique2esinto

thesoil

PinconnecJngthecranktothe

connecJngrod

ConnecJngRod

Plunger(Steelrod)

The plunger’s design was later changed from a joint at the top to a joint on the side.

The connecting rod remained the same but the connecting pin was replaced with a

screw to achieve the coupling.

This plunger design also did not need two separate inner and outer parts for depth

adjustment. We could simply do it by adding more holes for connecting the screw.

We had to shift from a steel based plunger to a nylon one. The steel provided huge

movement resistance as it did not allow any self abrasion. While passing through the

rubber flap at the bottom it would tremendously increase the stresses in the machine

frame. The frame also broke down as a result and we immediately decided to shift to

a nylon plunger. The nylon allowed self abrasion and adjusted to the design and

especially adjusted well with the rubber flap at the bottom.Hence, the plunger was

initially fabricated in metal and its length was made adjustable by having it made in

parts (inner & outer). Later it was made of a single nylon rod and the adjustability

was given by having different attaching points with theconnecting od

! !

Fig 3.13 Steel plunger and its sleeve Fig 3.14 Design correction of connecting

Rod,

! 16

Plungertop-outer

part

Plungerbo2om-inner

part

!

Fig 3.15 Inspection of plunger mechanism

!

Fig 3.16 Modified plunger mechanism for stage 3

! 17

Connec&ngRod

Plunger

Plunger’sSleeve

SleeveHolder

Crank

OldDesign

NewDesign

PlungingDepthadjustment

withseveralholeswith

threadsfora?achingwith

connec&ngrod

Connec&ngRod

Plunger

!

Fig 3.17 Nylon plunger with adjustable depth setting

Briquette picking mechanism

The briquette picker was initially directly mounted on the same shaft as the crank.

Hence, the rotation speeds were the same. For every rotation of the crank or a single

punching action of the plunger the picker would also complete one rotation.

However, as there were four cups in the picker it would pick up 4 briquettes per

rotation, when only one needs to be plunged. Hence, we covered the other 3 cups

(as shown in the image below) and briquettes were picked up by only one of the

cups. But in this arrangement we found that the percentage of briquettes being fed

to the pipe was less than 50%. We observed two problems some of the briquettes

being picked up were being thrown out of the box instead of being directed into the

pipe and due to high speed of rotation of briquette picker (same as that of the

plunger crank) briquette picking was not consistent.

As a first step we attached a lid to the briquette box to prevent briquettes from being

thrown out. And then we decided to reduce the speed of the picker 4 times and use

all 4 briquette picking cups instead of one. Now we could have one rotation of

briquette picker for every 4 rotations of the crank plunger. Even after attaching the

lid, Thespeed reduction required an additional chain and sprocket arrangement, as

well as redesigning of the frame. A separate shaft was mounted with a sprocket and

the picker box was connected to the crank shaft through a chain. But, the reduced

speed improved the briquette picking mechanism considerably.

! 18

Another issue we faced was briquettes getting stuck at the corner near the plunger

sleeve bottom or in the rubber pipe itself. We understood that the smoothness of the

e corner joint of the metal pipe was the main blocking point and made it smooth and

increased its inclination.

! !

Fig 3.18 Explaining the issue with the neck of the sleeve for plunger

Fig 3.19 Depicting the cumulative effect of the connecting pipe and the neck of

the sleeve in restricting the briquettes from reaching the sleeve

!

Fig 3.20 The modified picker mechanism for stage 3

! 19

Brique2estoragecontainer

Pickercoveredcups

Containerlid

Brique?esstuckatthecorner(ofmetalpipe)&

intherubberpipe(orangecoloured)

PlungerSleeve

!

Fig 3.21 The modification for the picker mechanism

Rubber stopper flap

A rubber flap was used below the plunger to stop briquettes from directly falling

down. But choosing the rubber was a tricky issue. The harder rubbers would provide

higher resistance while opening whereas softer rubber would get stuck between the

plunger and the sleeve corner during the return motion of the plunger. But trying 7-8

different types we were able to identify one ideal for our purpose

! 20

Brique2ehiVngmarks

!

Fig 3.22 The position of the rubber flap and the problems associated with its size

But still the rubber flap offered more than desired resistance to the plunger

motion and to counter this we increased the diameter from 3.5 to 5 inches. This

helped us achieve smooth motion of the plunger

The new 5 inch diameter rubber holder

!

Fig 3.23 Modified rubber holder (size increased)

! 21

3.5 Differential

To allow easy turning of the machine we decided to use a differential over a clutch

mechanism as the former was more compatible with the 8 inch width constraint of

the frame. The differential is a simple mechanism which allows the two powered

wheels to move at different speeds, thus, allowing the machine to turn and not

remain straight rigidly. We chose the differential of a three wheeler / auto rickshaw

called ‘Kerala’. We chose it mainly for its compact design, which matched our needs.

Though initial assembly and incorporation of the differential was a challenging and

time consuming as we had to encounter couple of failures and damages to internal

gear, we were able to get the desired results.

! !

Fig 3.24 Position of differential in Fig 3.25 Actual differential being used

the machine

3.6 Wheels & Axles

The same wheels were used as Prototype 1, flat and wide with small lugs. Two

separate axles were used for transmitting power from the differential to the two

powered wheels. These axles were in contact with internal differential gears through

a spline. But the point of contact of the axles with the differential gears is vulnerable

to high stresses and we had our axle breaking during testing. This forced us to use

one with larger diameter and more strength.

Note: A detailed material & load analysis can be submitted once the functional

prototype is ready and proper load analysis is possible. This analysis would be

helpful for the final production design of the applicator.

! 22

For the rear wheel initially we used a fabricated flat wheel but moved onto a

readymade nylon castor wheel, as it was smoother on and off the field.

! !

Fig 3.26 Fabricated castor wheel Fig 3.27 Rejected castor wheel (too heavy)

Another point of concern was the rear wheel and frame joint, which even broke

during testing. A better wheel fixing mechanism shown below did the trick.

! !

Fig 3.28 Space available for the position Fig 3.29 Mounting for the sleeve

of the power train

3.7 Acce lerator

A thumb based accelerator has been used. This particular accelerator design was

specifically chosen as it could be set at a particular throttle and keeps moving almost

! 23

at constant speed. This is much better compared to a handle based accelerator (like

the ones used in motorcycles) as it makes it easier to control the machine in a

planted field.

3.8 Testing

Testing was done in fields in Ludhiana. The first round of tests were conducted in dry

land conditions and the second round in wet field conditions similar to ones faced

during paddy transplantation.

! !

Fig 3.30 Dry dynamic testing of prototype 2 Fig 3.31 Stage 3 - completed prototype

Prototype 2

During dry field testing we faced issues such as:

• Inconsistency in plunging

• Inconsistency in briquette picking and placement

But fine tuning and adjustments to these mechanisms helped us achieve the desired

performance in dry land conditions.

Next the machine was tested in wet field conditions and here we faced the following

issues:

! 24

• Mobility and Maneuverability: The machine was immobile in dense wet soil

and was getting stuck. The inappropriate weigh distribution meant that that

most of the weight was concentrated on the non-powered back wheel. This

led to its sinking into the soil. Whereas the wider powered wheels remained

on the surface and slipped (also because of the lesser weight over these

wheels) thus was not able to create enough traction. Further concentration of

weight on the rear castor wheel did not allow the machine to turn easily, as for

that to happen, the castor wheel should not be loaded with weight

! !

Fig 3.32 Wet dynamic testing at Fig 3.33 Failure during wet dynamic

testing stage 3 of prototype 2

of prototype 2

3.9 Solution

One of the major problems was that the machine was very heavy and to make things

worse the weight was unevenly distributed. The gear box itself weighed 35-38 kg

and was placed behind the powered wheels. Further, the plunging mechanism and

the 10-15 kg engine were also placed behind the front wheels. This made the

machine rear-heavy and resulted in the non-powered castor wheel getting stuck in

the field during the motion. The gear box was designed to place briquetted at 50, 40

and 30 cm spacing, as per the farmer’s choice. We thought it would be better to have

a sleeker, lighter and easily detachable gear box which places briquette only at a

particular spacing. And, different gear boxes can be made available for placing

briquettes at desired intervals. Briquettes can then be placed at any desired interval

! 25

by attaching the appropriate gear box. Apart from saving close to 15-18 kg, the new

design for the gear box would allow us to place it between the powered wheels and

thus allow us to have a more favourable weight distribution and improved mobility

during operations.

Further we thought the design and size of the lugs on the wheels could also be

improved to generate enough traction. A possible solution was to use broader lugs or

ones similar to the ones on tractor/ paddy trans-planter wheels.

Criteria Aspect Details

Prototype Feature Engine: 3.5 Hp 70 cc Higher power and lower rpm 15 kgs with internal gearbox

Frame Redesigning to fit new engine, gear box and briquette plunging and picking mechanism

Gear Box To bring down engine rpm to wheel rpm of 40 To allow for variable briquette placement interval N e u t r a l O p t i o n i n c l u d e d t o discontinue plunging while machine was in operation

Plunging Mechanism Crank driven nylon plunger that allowed flexibility in depth of placement

Briquette Picking Mechanism

Picker synchronized with plunger picks up a briquette and places it below the plunger on top of a rubber flap Plunger while going down takes this briquette and places it in the soil

Wheels 2 Lugged Front Wheels: To provide sufficient traction in puddle fields

1 rear free wheel: To close furrows and provide balance &

maneuverability

! 26

Table 3.1 Outline of stage 3

Stage 4: Fabrication and Testing of Prototype 3

4.1 Fabrication

To overcome the challenges faced in operations of the previous design, we

conceptualized a new design, and started the fabrication process in Delhi.

Unfortunately, the fabricator we worked with in Ludhiana on the initial design was not

able to devote much time off late. In Delhi initially we had to work with several

fabricators rather than have one dedicated to us. But under this arrangement making

modifications to design was a challenge. Fortunately, Dr.Indramani Mishra of IARI

(Indian Agriculture Research Institute) was kind enough to allow us access to

equipment at the lab as well as testing fields.

In order to address the major concerns highlighted in the testing of the second

prototype we realized we had to design almost a completely new machine. The

engine & gearbox had to be shifted. A completely new gearbox design had to be

made to reduce weight and speed and increase torque. The frame design also had

to be reworked. The plunger design was altered for improved performance in wet soil

conditions and even though the picker mechanisms remained unchanged it had to

be mounted differently considering the new requirements.

Several design options were considered to achieve these objectives and the one

finally chosen along with the advantages it had over the previous design is shown

below in the image.

Differential A readily available differential system was added to allow easy turning of the machine

Drawbacks Poor Mobility and Maneuverability in wet

soil

Inappropriate weight redistribution heavily inclined towards the back wheel

Proposed Solutions

Reduce Weight Improve weight

distribution

Redesign Gear box Rearrange placement of gear box and engine

! 27

4.2 Weight balance shifting

The weight distribution of the machine was shifted forward by mainly shifting the

engine in front of the powered wheels by making the gearbox compact enough to fit

between the powered wheels. This arrangement provided torque balance about the

powered wheels and thus allowed the machine to be lifted about the wheel easily,

thus making turning the machine easy.

! !

Fig 4.1 Analysing prototype 2 and its shortcomings and improved design for Stage 4

! !

! 28

OldDesign NewDesignHeavierGearBox;behindthe

poweredwheels

Engineattherear

LighterGear

Box;between

thepowered

wheels

Engineatthe

BiggerLugson

wheels

Fig 4.2 Fabricated prototype 3 with Fig 4.3 Fabricated stage 4 prototype

round rim tyres with flat rim tyres

4.3 Weight reduction

Major weight reduction was achieved in the gearbox and through the following steps:

• Changing to Material of construction of casing from Mild Steel to Aluminium

• Using of Internal differential to eliminate the use of separate differential casing

and of any coupling shaft between them.

• Discarding feature that allows variable briquette spacing option

4.4 New power-train design

• New gearbox design with internal differential

• Gear ratio increased to provide higher torque and lower speed

• Power transmission by chain as compared to coupling used between engine

and gearbox earlier

Major advantages over the previous design:

- Vastly improved Mobility in wet mud conditions

- Much easier to turn by lifting the machine from the back

- Much lighter machine

- Stronger frame

! 29

!

Fig 4.4 New position of gear box and chain drive

The main design challenge faced during this phase was that of making the machine

move in wet fields. Multiple wheel and ski designs were tried before we arrived at

our final solution.

4.5 Engine

Engine- vibration was resulting in chain coming off often and to counter this and

reduce vibrations and increase stability we decided to secure it with rubber mounts.

4.6 Gear Box

A higher gear ratio of 27was used to achieve higher torque. The feature to allow

variable briquette placing was discarded. This meant that the gear box was much

lighter. Further, use of an internal differential and aluminum casing instead of mild

steel casing lead to more weight reduction

! 30

Chainfrom

engineto

gearbox

Newgearbox

withinternal

differenJal

!

Fig 4.5 Fabricated new gearbox with aluminium case

4.7 Frame

The frame’s design was changed to fit the new needs. To make it stronger a thicker

frame of 14 gauge was used. The handle design was changed to make it more user

friendly. We decided to replicate the wheel barrow handle design which we felt was

much more comfortable and easier to control.

Earlier design had chains and sprockets alignment & stability issues. The reasons for

this was high speed of motion for the one connected to the engine, the length of the

one connecting gear box and crank, and high gear ratio for the briquette picker one.

These were resolved through modifications to the frame, addition and inclusion of

fabricated guides to reduce the falling of chains.

! 31

!

Fig 4.6 Problems faced due to the length of the gearbox-crankchain

!

Fig 4.7 Guideway for the chains

4.8 Wheels & skis

Navigation in wet soil conditions was a major challenge with the previous prototype

and this meant that we had to design more effective wheels. 5 different versions of

the wheel were fabricated and tested before identifying the one that suits our need

the best. The designs were mainly based on transplanter & power tiller wheels used

for deep wet mud conditions. They have been described below.

Version 1: Paddy trans-planter wheels - Pipe wheels with long & sharp lugs

This wheel’s design was based on transplanter’s wheels. It was not heavy as it was

fabricated mainly from hollow pipes. The main issue during testing of this wheel was

! 32

LongChain:GearBoxtocrank

FabricatedChainGuide

that it sunk very easily in deep wet mud and hence could not move. The long lugs

would also dig into the soil and create a hole for the machine to get stuck.

!

Fig 4.8 Pipe wheels with long & sharp lugs

Version 2: Pipe wheels with additional skis

The skis were designed and fabricated to improve the machine’s performance. Even

though with the skis the machine’s movement slightly improved in wet mud, it still

easily got stuck.

!

Fig 4.9 Pipe wheels with additional skis

! 33

Skis

!

Fig 4.10 Failure of pipe wheels with additional skis

Version 3: Pipe wheels with small flat lugs

As mentioned above, we observed the long lugs digging into the soil and creating a

hole for the wheel hence, making it difficult for the machine to move forward. We

thus decide to try shorter and a higher number of lugs on the wheel. The higher

number of lugs would also reduce the force transmitted per lug, thus, further

reducing the chance of digging into the soil. The performance of this wheel was

much better than the previous wheel but was still not good enough for farm

operation.

!

Fig 4.11 Pipe wheels with small flat lugs

! 34

Version 4: Flat wheels with triangular lugs

We decided on trying flat and wide wheels with longer triangular lugs. This was

similar to the power tiller wheels used for wet mud conditions. It was much heavier

than the other wheels and with a 4 inch larger diameter. This wheel was designed to

avoid sinking of the wheel, increase traction during movement and also make it

easier to turn. This wheel was 4 inches larger in diameter than the other 3 sets of

wheels. It had a width of 3 inches. The wheel was successful in navigating through

wet soil.

!

Fig 4.12 Flat wheels with triangular lugs

Version 5: Flat wheels with small flat lugs

Simultaneously, we also designed extra wide wheels (5 inches) with a thin rim and

short lugs. But since the ones with triangular lugs were successful we decided to

continue with them.

4.9 Axles

During testing, one of the axles failed by torsion. The axle and keys got twisted. We

therefore decided to redesign the axle for higher load carrying capacity. The axle

was re-designed; new material was used and was hardened. The wheels were fixed

on the axle using splines, and keys were eliminated. The change in design mainly

consisted of diameter increase and cutting of splines on the axle. The material of the

axle was then changed to much stronger EN353. The axle has been providing much

improved performance since then.

! 35

! !

Fig 4.13 Damaged keys – key failure Fig 4.14 Failed axle – torsion failure

!

Fig 4.15 New axle with improved design

4.10 Crank

To increase stability the mounting for the crank was redesigned. The new mounting

had two journal bearings mounted on an extended frame. And, its thickness was

increased to improve strength and stability.

! !

Fig 4.16 Comparison of the new-redesigned crank with the old one

! 36

4.11 Testing

! !

Fig 4.17 Field preparation

!

Fig 4.18 Dry dynamic testing of stage 4 machine

Testing was done in fields prepared in IARI (Indian Agriculture Research Institute) in

Delhi. The first round of tests were conducted in dry land conditions and the second

round in wet field conditions similar to ones faced during paddy transplantation.

The machine performed well in dry land conditions but again faced some issues in

wet land conditions. Though unlike the previous attempt, the machine was able to

easily navigate the tough wet soil conditions and was easy to handle and

maneuverable. The machine was easy to rotate and due to better weight balance

could be easily lifted and made to pivot and rotate on the spot in dry soil, but in deep

wet soil it had a radius of 60-70 cm.

! 37

Though success achieved in mobility was very encouraging performance of plunger

in wet soil was a major challenge. The nylon plunger the mud (as in image above)

inside the plunger sleeve and this impeded its motion. Nylon creates hydrogen

bonds, and hence attracts water, which in turn makes mud stick to it easily. We are

therefore, shifting to a Teflon plunger which can repel water and avoid this situation.

!

Fig 4.19 Failure of the plunger due to increased friction and clogging because

of wet soil

4.12 Solution (Next Step)

Due to physical properties of nylon we are thinking of moving to a Teflon plunger that

would prevent mud from sticking onto its surface and impeding the motion.

Teflon plunger is smooth as compared to Nylon and the locking forces generated

during the plunge would be significantly reduced preventing the slider crank

mechanism from locking.

New Teflon plunger was installed and tested in air by inserting a container consisting

of dense mud resembling the paddy field condition beneath the plunger. The new

plunger was rigorously tested for an hour and the plunging was smooth.

The current mechanism is ready to be tested in actual field conditions.

! 38

! !

Fig 4.20 Nylon plunger is replaced by Teflon plunger

The machine was taken into the field but the starting mechanism of the TVS moped

engine failed. The current automobile engine has been highly unreliable for on- field

wet muddy conditions. A decision was taken to procure a new engine.

! 39

Stage 5: Fabrication and Testing of Prototype 4

5.1 Honda GK 200 engine

A new engine Honda GK 200 was procured best suited for agricultural applications.

ENGINE SPECIFICATION

Table 5.1 Specification of GK 200 Engine

Fig 5.1 Honda G 200 engine

Model GK 200

Type 4 stroke, Air Cooled, Single Cylinder, Horizontal Shaft

Displacement 197 cc

Net Engine Power 2.2 kW / 3 HP @ 3,600 rpm

Net Engine Max. Torque 7.9 Nm @ 2,500 rpm

Fuel Tank Capacity 3.3 litre (Kerosene), 0.35 litre (Gasoline)

Ignition System

Fly wheel Magneto Ignition, Transistor Type Magneto

Ignition

Air Cleaner Oil Bath Type

Dry Weight 17Kg

Dimensions LxWxH 330 x 405 x 425 mm

! 40

5.2 Clutch Mechanism

The previous engine had a centrifugal clutch mechanism which allowed the machine

to start at no load condition.The present engine doesn’t have an in built clutch

mechanism so we had to incorporate a clutching mechansim.

Selection of Clutch

1.Friction clutches:

Transmssion power by means of friction lining b/w the friction plate and pressure

plate.

2.Pulley and belt system:

The idler pulley is used as clutching mechanism.It is basically operated in two

postions to make the belt loose or tight.

We chose the second mechanism for it’s simplicity in design and fabrication.

V-type belts were chosen along with B-type pulleys according to the numerical

calculations performed considering the present gear ratio and the torque to be

transmitted.

The engine was mounted to the chassis along with the driving and driven pulleys.

The next step was to fabricate the idler mechanism and install it according to the

space constraints in the frame. The positions of the idler was decided and set

accordingly by installing the belt with the pulleys.

The new engine and power transmission mechanism was ready for testing.

! 41

! !

Fig 5.2 Clutch mechanism for the new power train

5.3 Testing

Dry land testing:

The machine was not able to disengage and considerable slipping was observed b/w

the belt and the driving pulley. Excessive heat was generated in the engine

pulley(driving pulley)

Wet land testing:

The machine was not able to move forward followed by excessive slipping earlier

observed.

The machine with the old engine (TVS moped) was able to move in wet muddy

conditions but the new engine with the same power was unable to do so.

Clearly the belt mechanism not able to transfer power as the load conditions in wet

muddy field is much more than we anticipated in our calculations.

Slipping mechanism verifies our observation.

! 42

! ! .

Fig 5.3 Testing of the stage 5 machine – prototype 4

5.4 Solution

The failure of belt pulley mechanism made way for the friction clutching as reliable

mechanism in our machine. The friction clutch would be manually operated by the

operator to engage and disengage the drive.

! 43

5.5 The Final Design

!

Fig 5.4 Side View

!

Fig 5.5 Front View

! 44

!

Fig 5.6 Top View

!

Fig 5.7 Isometric View

! 45

RESULT AND DISCUSSION

The Urea Deep Placement Applicator has been successfully designed and a

prototype has been fabricated which performs the operation satisfactorily.

The result of our project has been fairly positive and it gives way for further

development in this area of research. Various optimization techniques can be used

for further weight reduction. Improvisations in design could lead to a more rigid and

stiffer machine. Research on selection of materials for different components of the

machine can improve the handling and maneuverability of the machine further.

Further scopes in the field are the development of a Double Row UDP Applicator and

an Adjustable spacing Applicator. Also the integration of the UDP Applicator into a

rice transplanter can act as a boon in paddy production.

! 46

CONCLUSION

The UDP Applicator developed by our team is a success and performs the plunging

of Urea briquettes at equal fixed intervals properly. The percentage of briquette

placement in the soil is more than 94%.

The scope of our development is magnanimous if implemented properly in the

country and worldwide. It could create a huge impact on the production of paddy ,

decrease the consumption of urea immensely.

! 47

REFERENCES

Research Papers:

1. Markley G.L., Assembly System and Method for Chain Drive System, US

Patent No. 8387244 B2

2. Lupin M.S., Lazo J.R., N.D, et al, Briquetting, TP 963.4.U7B74

3. Crolla D.A., El-Razaz A.S.A., Combined Lateral and Longitudnal Force

Generation of Tyres on Deformable Surfaces, Journal of Terramechanics, Vol

3, pp220-245

Books:

1. Nortan N.L., Integrated Approach To Machine Design

2. Timoshenko, Strength Of Materials

3. Bhandari V.B., Elements of Machine Design

4. Rattan S S, Theory of Machines

Websites:

1. www.ifdc.org/Technologies/Fertilizer-Deep-Placement-(FDP)

! 48