Department of Mechanical Engineering Full Work - Copy

MEE 522 DESIGN PROJECT

Design of Solar-Powered Corn Grinding Machine

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Design of Solar-Powered Corn Grinding Machine 2011

Department of Mechanical Engineering

University of Benin

Design of a Solar Powered Corn Grinding Machine

By

September 2011

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Table of ContentsIntroduction...........................................................................................................................................1

The Corn Grinder...............................................................................................................................2

The Components of the Grinding Machine........................................................................................2

The Solar Panel..................................................................................................................................3

How the Panel Works....................................................................................................................4

Economic Importance of the Solar-Powered Corn Grinding Machine...............................................5

Literature Review..................................................................................................................................7

Design (CONCEPTUAL DESIGN, DESIGN CONSIDERATIONS, POWER CALCULATIONS AND COST ANALYSIS)...........9

Isometric Diagram of the Corn Grinding Machine...........................................................................10

3D View of the Machine..................................................................................................................11

The Design Concept.........................................................................................................................12

The Solar Power System..................................................................................................................12

The Solar Panel............................................................................................................................13

Solar Regulators...........................................................................................................................14

The Battery Bank.........................................................................................................................14

Power Inverter.............................................................................................................................15

Design Considerations.....................................................................................................................15

Power Calculations..........................................................................................................................16

Solar Panel Rating........................................................................................................................17

Cost Analysis....................................................................................................................................19

Economic Analysis...............................................................................................................................20

Registration (Business Name)..........................................................................................................20

Obtaining Licenses, Permits and approvals.....................................................................................21

Selection of Technology...................................................................................................................21

Advertisement.................................................................................................................................22

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Chapter One

Introduction

Corn is a cereal grain and or maize is a common name for cereal grass widely

grown for food and livestock fodder. It is a natural source of protein as well as

a source of carbohydrates and is made into many different kinds of foods. It is

a staple food in Nigeria and serves as a rich source of carbohydrate for both

man and livestock; as it can be used to prepare corn starches for both man and

animals.

Corn can be grounded either wet to produce paste, or dry to produce corn

flour depending on the intended use.

It is better to carry out this process with the use of electricity to power the

corn grinding machine due to the over-dependence on petroleum fuel (which

generates carbon waste to the atmosphere). This carbon waste generation is

reduced and a cleaner means of carrying out this process is established. And as

a result of the unstable power supply in the country an alternative means of

power source is considered here using solar panels to power the grinding

machine which is cleaner and environmental friendly.

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The Corn Grinder

A grinder is a machine for producing fine particle size reduction through

attrition and compressive forces at the grain size level and this requires a lot of

energy.

The corn grinder makes flour or paste (when mixed with water) out of corn and

is a machine that is designed to grind corn with the use of stone grinder and is

powered by a solar panel which is a much cleaner source of powering the

grinding machine and on a long run more economical.

The Components of the Grinding Machine

The corn grinder was designed to be simple with fewer components making it

a cheaper option to the normal corn grinding machines available. The machine

comprises of the following components:

The Hopper: this is a large funnel shaped dispenser or container for storing

and dispensing the grain into the grinder.

Shaft: this is a rotating part used to transmit torque required in grinding the

corn from the motor to the grinder.

Grinder: this is the tool that performs the grinding. The grinder used in the

machine is a stone grinder. Stone grinders have two circular grinding stones.

One stone turns against a stationary stone. Grooves are cut into the stone

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radiating out from the centre of the stone to the ends. These grooves become

shallower as they near the ends of the stone, until they disappear at the outer

edges. When grain is ground, it falls through a channel into the centre of the

two stones. As the stone rotates, it pulls the grain out through the channels

where it is ground. The flour falls out the outer edges of the two stones.

The Motor: is the machine that converts electrical energy into rotary motion

and is used to drive the shaft which in turn rotates the grinder to grind the

corn.

Bearing: this serves as housing for the shaft and it also supports the load of the

shaft thus reducing the weight acting on the motor from the shaft.

Feeder: Grounded or processed corn is collected from the feeder.

Knob: this is used to adjust the spacing between the grinding stones to

determine the smoothness of the grinding.

Base: this serves as a support for the machine.

The Solar Panel

Solar radiation is a general term for the electromagnetic radiation emitted by

the sun. We can capture and convert solar radiation into useful forms of

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energy, such as heat and electricity, using a variety of technologies but in this

case we are converting to electricity.

The basic principle of solar energy is that every location on Earth receives

sunlight at least part of the year. The amount of solar radiation that reaches

any one "spot" on the Earth's surface varies according to these factors:

Geographic location

Time of day

Season

Local landscape

Local weather

In this case we are capturing the energy from the sun using solar panel and

converting to electricity.

How the Panel Works

As the sunlight strikes the silicon cells in the panel, it excites the electron which

are knocked free to form electric current, metal contact points carry the

current away and completes the circuit. This power is then transferred to a

rectifier (solar regulator or charge controller) and to a battery which stores the

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charge or current and then to an inverter which converts the DC voltage to AC

voltage.

Economic Importance of the Solar-Powered Corn Grinding

Machine

Due to the fact that corn meal is highly nutritious and is an everyday need for

most home and farmers who intend to use for their animals, there is a great

need for grinding corn and hence the need of a grinding machine.

The flour you buy in the store - even the whole wheat kind - is dead. Once

ground, wheat loses all of its nutrients within 12 hours. Ground wheat left out

longer than a week will even become toxic (always either freeze your freshly

ground flour or better still, grind just enough for your daily use). To combat

this, manufacturers will add preservatives and vitamins to store-bought flour

and breads. These preservatives wind up in your body and stay there for a long

time. You can avoid these scary chemicals by grinding your own fresh flour in a

grain mill at home.

Producing energy can be dirty work. Carbon emissions, coal slurry, nuclear

waste, and other pollutants can wreak havoc on the environment, and cause

health problems. And many energy sources are in limited supply.

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This solar-powered corn grinding machine is also of high importance to the

economy because it provides an alternate means of grinding corn different

from the conventional use of diesel powered engines which are very noisy and

releases carbon waste to the atmosphere. This is a gas that causes greenhouse

effect and is hazardous to the environment. And in addition to this the

machine production will serve as a source of income to the designer and also

provide jobs to persons who will be in charge of operating them.

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Chapter Two

Literature Review

Early grain mills were driven by paddle wheels which were attached to a shaft that turned

the millstone. The millstone was on top of a similar sized stone that was stationary and this

simple arrangement worked well in areas where water ran swiftly. There was no gear which

was good because of maintenance, but it was also a disadvantage because there was no

consistency in the speed of the mill. During the Roman Empire, they advanced to vertical

wheels with some estimated at 2.4 to 3.2 tons per hour. By 1086 in England, a census was

taken and there were 5,624 water-powered flour mills.

The classical grain mill is designed to be driven by water. Some were driven by livestock

while others were driven with slave labor. At the end of the eighteenth century, Oliver

Evans revolutionized grain mills when he invented, patented and promoted a fully

automated mill.

Modern mills usually use electricity to turn heavy steel or cast iron flat and serrated rollers

to separate bran and germ from the endosperm. White flour is made of the endosperm.

Many bakers still prefer the stone-ground flour because of its texture. The bakers fear that

much of the nutritional value is lost in the heat created by the metal rollers of the modern

flour mills.

The modern corn mills can produce enormous amounts of product, but in the production

process, there is often lost the goodness of the whole-grain. Whole-grain products can be

found in the grocery store, but it is difficult to find what you are truly looking for in terms of

texture, flavor and cost.

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Today, we have advanced to the modern home grain grinders which can produce virtually

the same and better quality flour as the modern gristmills. Modern grain mills are easy to

use, lightweight, adjustable to a special grind, can produce as much or as little as needed,

and have a consistent quality.

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Chapter Three

Design (CONCEPTUAL DESIGN, DESIGN CONSIDERATIONS, POWER

CALCULATIONS AND COST ANALYSIS)

This corn grinding machine is designed for simplicity with fewer components to

reduce the power needed to run. This machine comprises of the following

parts.

AC Motor

Grinder (Stone Grinders)

Hopper

Shaft

Feeder

Bearing

Knob

Base

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Isometric Diagram of the Corn Grinding Machine

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HopperGrinding CompartmentShaft

BaseFeeder

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3D View of the Machine

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The Design Concept

Corn is fed through the hopper and from the hopper goes to the grinding

compartment and through the stationary stone. Grooves are cut into the stone

radiating out from the centre of the stone to the ends. These grooves become

shallower as they near the ends of the stone, until they disappear at the outer

edges. When grain is ground, it falls through a channel into the centre of the

two stones. As the stone rotates, it pulls the grain out through the channels

where it is ground. The flour falls out the outer edges of the two stones.

There is a shaft which passes a bearing connecting the moving stone to the

motor (AC), the motor receives power form a solar panel.

As current comes from the solar panel to the motor, the motor rotates and this

rotary motion is transmitted by the shaft to the rotating stone, and as the corn

come in through the groove of the stationary stone, the rotating stone crushes

the grain against the stationary stone. The smoothness can be adjusted with a

knob, the knob reduces the spacing between the stones.

The Solar Power System

This generates the power that is used to drive the machine. And it comprises of

the following components:

The Solar Panel which contains

photovoltaic cells

The Solar Regulator or

Charge Controller

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The Solar Panel

The solar panel converts sunlight into DC power or electricity. They are

classified according to their rated power output in Watts. The solar panel uses

photovoltaic cell (a device used to convert solar radiation directly into

electricity). The most common type is single crystal silicon solar cell. A standard

photovoltaic cell is a thin semiconductor sandwich, with two layers of highly

purified silicon. A semiconductor is a crystal that is constructed in such a way as

to yield certain specific properties that can be used in electrical circuits.

Transistors are made of semiconductors. Microprocessors are as well. In fact,

the entire field of modern electronics uses various forms of semiconductors, so

the implications are worldly. If you connect an electrical circuit to your

semiconductor sandwich when sunlight is shining on it, electricity flows.

Solar Regulators

The solar regulator or charge controller ensures that the battery is charged

properly and not damaged and that power is not lost or discharged. It feeds

The Battery Bank

Inverter

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current into the battery bank at the required voltage. Good solar regulators or

charge controllers draw the best performance out of the batteries and are very

important for economics because they influence efficiency. It also prevents

batteries from overcharging, overcharging causes gassing and loss of

electrolyte resulting in damage to the batteries.

This solar regulator will include a Low Voltage Disconnect feature, which will

switch off the supply to the load if the battery voltage falls below the cut-off

voltage. This prevents the battery from permanent damage and reduced life

expectancy.

They are rated by the amount of current they are able to receive from the solar

panel.

The Battery Bank

Deep cycle batteries will be used in system because they are designed to be

discharged over a long period of time (e.g. 100 hours) and recharged hundreds

or thousands of times, unlike conventional car batteries which are designed to

provide a large amount of current for a short amount of time.

Power Inverter

The power inverter is the main component of any independent power system

which requires power. The power inverter will convert the DC power stored in

the batteries and into AC power and then transmits this power to the motor.

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Design Considerations

The major factor considered in the design of the machine is cost and thus the

entire component selected were as small an efficient as possible due to the

fact that the machine will be powered using solar power which could be very

expensive if the machine requires a very high power to run.

The other factors considered are:

Shaft size and material: the shaft selected is a 1inch diameter shaft made

from mild steel.

Type and size of bearing used: a pillow block bearing of 1inch internal

diameter is selected.

Operation and control: turning the machine on/off will done using a

switch thus making it easier to operate

Maintenance procedures: since the machine was designed with fewer

parts, it is easy to maintain as it contains no hidden part.

Corrosion and wear of the material: as a way of preventing the material

from corroding the metal used in manufacturing the machine will be

painted

Motor capacity: an AC motor capacity of 500watts, 1200rpm is selected.

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Availability of solar energy: there is constant energy supply from the sun

to this part of the world and thus is the source for powering the

machine.

Power Calculations

The size of the motor is:

500 watts

0.67hp

1200rpm

50Hz

40µF

2.3Amps

Power-required to drive the motor

In order to size the solar panel, we need to determine the size of the motor

and also the amount of hours the machine will work per day.

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Device Power Rating Estimated RuntimeWatt Hour (WH)

Consumed

AC Motor

500 watts

0.67 hp

220V

Six (6) Hours per day 3000

Table 1 - Power Rating of the Electric AC Motor 1

Solar Panel Rating

The number of charge hours expected for the solar panel is 8hours.

Power Rating of the solar panel = Daily usage ÷ Charge hours

3000WH ÷ 8 = 375watts

Accounting for inefficiencies we add by 20%

375 × 1.20 = 450watts

The total number of panels needed will be:

450 ÷ 150 =3

Three (3) 150 watts panels will be needed

Amount of Batteries Needed

The 150 watts panel produces 4.4 amps thus

3 × 4.4A = 13.2 A × 8Hrs = 105.6Ah

105Ah batteries, should be discharged to no more than 50%, thus we divide

total amps by 50% of 105Ah = 50Ah.

105.6 ÷ 50 = 2.112

Therefore two (2) 150Ah batteries will be needed

Regulator or Charge Controller Size

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For the 20A regulator

One 150W panel produces around 4.4 Amps.

3 x 4A = 12A

So for Six (3) Solar Panels we will need:

3 ÷ 3 = 1

Therefore we will need one charge controller for the machine.

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Cost Analysis

S/No Part Name Quantity Dimension/RatingUnit Cost

(N)Total Cost

(N)

1Electric AC Motor

1500W, 220V, 0.67hp, 50Hz,

1200rpm15,000 15,000

2Shaft (Mild Steel)

1 1in Dia. By 300mm 2,000 2,000

3Hopper (Sheet Metal)

1 - 1,000 1,000

4Bearing (Journal)

1 1in inner Dia. 5,000 5,000

5Base (Cast Iron)

1 - 5,000 5,000

6Feeder (Sheet Metal

1 - 1500 1,500

7Grinder (Stone Grinder)

1 - 7,000 7,000

8 Knob 1 - 500 500

9Cost of Fabrication

- - 5000 5,000

10Solar panel (PV Cells

3 150W, 4.4A 75000 225,000

11Battery (Deep cycle)

2 150Ah 30000 60000

12Solar Regulator

1 20A 20000 20000

13 Inverter 1 1000W 30000 30000

Grand Total 378,000

Table 2 - Cost Analysis of the Solar-Powered Grinding Machine

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Chapter Four

Economic Analysis

A good design and manufacture of a powerful machine without an economic

value is as good as useless because if a machine cannot meet a need or is too

expensive to obtain, it probably might be in the shelve for long and thus

redundant. Thus it is of high importance that engineers carry out an economic

analysis of a machine before putting it into the market.

From the knowledge of CED, we learnt that for a product to have a market, it

must satisfy a need for which consumers and anticipated users are willing to

pay for. The following steps are taken to ensure economic viability.

Registration (Business Name)

We will ensure that our business name is registered at the state and territory

level of government. This involves registering our business name with the

corporate affairs commission.

Location and Site Selection

In selecting and locating our business site we will take into consideration the

availability of, and proximity to basic amenities like:

Raw materials

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Marketing location

Security

Availability (reliability of power supply)

Possibility of expansion

Obtaining Licenses, Permits and approvals

We will ensure that we find out the licensing requirements that apply to our

new business. The federal, state and local governments are all responsible for

the different licenses, permits, registration and certificate that applies to

businesses.

Selection of Technology

We will ensure we select appropriate technology that will include:

Reduced real and implied cost of technology

Reduced maintenance cost

Capacity of the technology in relation to the expected level of operation

Adaptability and flexibility of the technology

Efficiency of the technology

Lifespan of the technology

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Advertisement

After the economic analysis and design of the machine the next step is to find

means of bringing our product (the solar-powered grinding machine) to the

notice of our prospective buyers. This could be done by the following:

Exhibitions

Showcasing in a showroom

Networking

This will enable us to convince our prospective buyers that our product is the

best.

Documents

Department of Mechanical Engineering Full Work - Copy