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OHIO University Mechanical Engineering Project Proposal Report

GOOD EARTH BEAN SHELLER

Team Green Bean

Mark HritzMichael SeiserSean MefferdDan Knuckles

Andrew JanosikChris Allen

11-16-2011

Abstract

Team Green Bean is comprised of six mechanical engineering seniors who have taken onthe task of addressing the needs of a local client as a year-long capstone project. Thisteams chosen project isto design and build a dried bean sheller prototype for Good EarthFarm, a local non-profit organization in Athens, Ohio. Due to the long processing timeinvolved when the beans are shelled by hand, the farm has a need to employ a mechanicalprocess to shell their annual harvest. This report includes a detailed description of theclient, the clients needs, the specifications determined by the team, and the reasoningbehind the determined specifications.

> Very good overall work on problem

definition and specifications.

> Report content and quality meets orexceeds all expectations.> Specs are approved, under thecondition that the team verifies that allcustomer requirements and standardsare included, and the source of thevalues is more clearly defined.> Please see comments throughout

report


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1.0 Introduction

The process of removing dried beans from their pods (also known as shelling ordehulling) is an incredibly time consuming task when done by hand. Due to the fact thatthere are few beans contained in each bean pod, the time required to process any

deliverable quantity of produce makes bean farming very costly for small farms. Whileshelling machines are available commercially, the capacities of these systems only coververy small or very large operations with no alternatives available for mid-sizedoperations. Using a machine intended for small operations is hardly more efficient thanshelling the beans by hand and using an industrial machine intended for large operationsis not financially feasible.

There are typically two mechanical methods employed to shell beans. The first smallscale method forces the bean pod between parallel rollers and squeezes the beans out theend. The second, more industrial scale method uses vibrations or impacts to shake thebeans from the pods and then separates the shelled beans from the pods using screens.

Large scale harvesting combines use this method by tumbling the bean pods inside of arotating screen. When used for their intended applications and scale both methods workeffectively and provide a favorable ratio of cost to productivity. However, for a medium-sized farm neither application is appropriate. Machines that employ the roller methodtypically require an operator to align the bean pods perpendicular to the rollers and feedeach pod into the machine by hand. This system works well for garden sized produceyields but becomes inefficient when dealing with a more substantial volume. Largermachines that employ the vibratory method require a large initial investment andconsume a huge footprint.

Across the United States, there are over 600,000 farms that operate in an average annual

sales class between $1,000 and $2,500. This sales class accounts for around 25% of allU.S. farms, the average size of which are about 55 acres. Farms of this class would fallunder the category of medium-sized, where small farms can be tended to with hand toolsand large farms necessitate heavy machinery. Although these account for a large portionof the total number of farms, they account for a much smaller portion of the overallmarket (Agriculture, 2011). Equipment manufacturers tend to lean towards producingmachines for high-dollar operations, ensuring that they will have a customer base that canafford the final product. This leaves medium-sized farms in need of mechanical solutionsthat are not currently mass manufactured.

Good Earth Farm in Athens, Ohio, is an example of a medium-scale farm in need of a

machine to shell beans. A not-for-profit farm, Good Earth operates on approximately 10acres of land, potentially placing them in the sales class mentioned above. Dedicated tofeeding the less fortunate, Good Earth relies heavily on volunteer work to perform dailyoperations. Although employing volunteers keeps operating costs down it does notguarantee a consistent workforce. For this reason, any sort of automation strengthens thefuture of the farm in that it reduces the dependence on volunteers. According to FarmManager Paul Clever, it takes 24 man-hours of work to yield just 3 quarts of shelledbeans. The average annual harvest at Good Earth Farm is currently about 6 bushels, each


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weighing in at 30 lbs, resulting in a total of 180 lbs of in-shell beans. No currentlyavailable shelling machine can efficiently and cost effectively process this amount(Clever, 2011).

Team Green Bean (TGB) is a group of six mechanical engineering undergraduate seniors

who are required to specify, design, manufacture, and deliver a prototype to solve aproblem encountered by the teams partner, Good Earth Farm. The teams goal is tocreate a machine that combines the financial feasibility of a small-scale application withthe automation of a large-scale application. This machine will accept dried bean pods asinput and produce shelled beans as output, requiring the operator to simply load the beanpods and remove the shelled beans.

1.1 Initial Needs Statement

Good Earth Farms needs a machine that will automate the process of removing beansfrom their pods. This process is currently being performed by hand as commercially

available machines are either too large or too small for the required scale of operation.Figure 1.1presents the bean pods as they are harvested, while Figure 1.2presents thebeans as delivered to the consumer.

Figure 1.1: Harvested Bean Pods

Figure 1.2: Processed (Shelled) Beans


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2.0 Customer Needs Assessment and Revised Needs Statement

TGB initially approached Good Earth to see if the farm had a need to implement amechanical solution to make a farming operation easier. Good Earth Farm then identifiedthree manual farming tasks that could be more efficiently completed using a machine.

The tasks of spreading compost, milling grain, and shelling beans were all cited asinefficient processes that consumed a significant amount of resources, with the task ofshelling beans further emphasized as the most labor-intensive task. Designing andmanufacturing a mechanical prototype to efficiently and cost effectively shell dried beanswas therefore chosen as TGBs capstone project.

Further communication with Good Earth clarified additional process conditions: thebeans are allowed to dry on the vine and then harvested, they must remain dry during theshelling process, and all commercially available machines are either too large or toosmall to meet Good Earths needs.

2.1 Evaluation / Weighting of Customer Needs

After meeting with Good Earth, Team Green Bean identified the needs of the projectpartner which are presented in Table 2.1. Team Green Bean determined many of thecustomer needs after performing hands-on experimentation with the bean pods, whichdetermined the hierarchy of needs which is presented in Table 2.2. Client Good Earthcurrently harvests approximately an acre of beans in-pod which yields approximately 6bushels of produce. This yield will then determine the capacity and design of theprototype.

Table 2.1: Initial Communicated and Observed Customer Needs List

Safe3 Bushels/HourSize and portabilityAble to fit through a standard 36 doorAdjustable for different beans/pods/foodsAdaptable to different power sourcesOperated by one personOperator maintainedStandardized parts

Easy to cleanSeparate pods from beans


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Table 2.2: Hierarchal customer needs list with weighting factors

1. Follows Industry standards (0.18)

1.1Safe

1.2Easy to clean

2. Efficiency (0.34)

2.110 lbs pods/hour2.2Operated by One person

2.3Separates Beans from Pods

3. Versatility (0.17)

3.1Adjustable for different beans

3.2Size and portability

3.3Fit through a standard 36 door

3.4Adaptable to different power sources

4. Operation (0.31)

4.1Operator Maintained

4.2Standardized Parts

Table 2.3: AHP pair wise comparison chart to determine weighting factors

Follows IndustryStandards Efficiency Versatility Operation Total Weight

Follows IndustryStandards 1.00 0.50 1.00 0.67 3.17 0.18

Efficiency 2.00 1.00 2.00 1.00 6.00 0.34

Versatility 1.00 0.50 1.00 0.50 3.00 0.17

Operation 1.50 1.00 2.00 1.00 5.50 0.31

2.2 Revised Needs Statement

There is a need for a bean processing machine capable of shelling a minimum of 3bushels of bean pods per hour, for a wide variety of bean types that include Jacobs Cattleand Painted Pony. The machine will greatly increase the rate of bean processing; thecurrent rate is 8 man-hours per quart of shelled beans. The machine will be designed tomeet FDA and OSHA standards. An effort will also be made to design the machine to fit

within a standard 36 door to accommodate other potential customers needs.


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3.0 Benchmarking, Standards and Target Specifications

3.1 Benchmarking

Through team research several existing methods to shell beans have been discovered.

Most commercial or store bought machinery that could be applicable to the clientsneedsare either too large or small, or are designed to process the wrong type of pods. TeamGreen Bean has found three different methods for shelling beans which use either a rollermethod, a tumbling method, or a shearing method.

3.1.1 Roller Method

The roller method of bean shelling can be found in several readily available hand crankand/or table top models; these machines are designed to shell fresh peas in the pod. Thepea pods are fed into two very closely spaced rotating rollers which squeeze the peas outof the pod and then pull the empty pods through the roller mechanism to be collected and

discarded. Most of these devices are too small for our needs and are designedspecifically for fresh peas. Figure 3.1is an example of a small table top pea sheller.

Figure 3.1: Representative Table Top Pea Sheller

(Homesteader's Supply)


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3.1.2 Tumbler Method

Shelling machines that use the tumbler method consist of a slowly rotating inner meshcylinder which contains a quickly rotating shaft with attached paddles, and an externalwall. The pods are loaded into the inner cylinder which rotates and directs the pods to

fall into the spinning shaft which breaks up the pods through contact with the rotatingpaddles. The shelled beans then fall through the inner cylinder mesh and are collectedfrom the external wall, while the empty pods remain within the inner cylinder to be latercollected and discarded. The only commercially available tumbler style machines aredesigned for an industrial scale and therefore are both too large and expensive. To putthis into perspective, a tumbling shelling machine with an appropriate capacity for theclients needs representative price point was quoted at $4,200 (Clever, 2011), which istoo expensive for a nonprofit farm. Figure 3.2 is an example of a commercial gradetumbler.

Figure 3.2: Representative commercial grade pea & bean tumbler (Alibaba JX)

(Alibaba, Zhecheng Jingxin Manufacturing)


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3.1.3 Shearing Method

The only device in production that our research uncovered that employs the shearingmethod is found in a rice huller. In this method the rice is fed onto a stationary tablewith an oscillating or reciprocating surface just above the table. The friction and shearing

forces applied by the table split the rice hulls open and then separate the chaff and grainsof rice. The chaff and rice grains are then separated using an additional device or process.Alternate Rice huller designs employ a rotating drum that shears the rice against a curvedsurface.Figure 3.3andFigure 3.4present an example of a rice huller.

Figure 3.3: Representative Rice

Huller

Figure 3.4: Rotary Rice Huller (AMS-9)

(Alibaba, Zhengzhou Amisy Trading

Company site)

Table 3.1: Product Benchmarking

Feature Roller Tumbler Shearing

Name Taylor Little Sheller Alibaba JX Amisy AMS-9 RiceHuller (rotary)

Size 14x 16.5x 27.5 47x 23.6x 43.3 Not listed

Weight 35 lbs 330 lbs Not listedCost $475 $3,000 $1,500

Adaptability All Beans Castor Beans Rice

Portability Carry Rollers Stationary

Rate 3 bushels/hr 14 bushels/hr Not Listed

Operation 1 Person, Electric 1-2 People, Electric 1 Person, Electric


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3.2 Standards

The following organizations have established standards that must be followed:Occupational Safety & Health Administration (OSHA), Food and Drug Administration(FDA), and National Electric Code (NEC) standards if the project design utilizes an

electric motor. OSHA standards might include operation height and mechanicalsafeguards. FDA standards might influence the types of materials that can be used forparts that come into contact with the beans. NEC standards might include groundingrequirements, secured electrical connections, and load limitations.

3.3 Target Specifications, Constraints and Design Criteria

By examining the results of the benchmarking research and the standards research, a setof target design specifications was created to ensure that the clientsneeds and nationalstandards are met. As the clients list of requirements is short, many of the designspecifications listed below in Table 3.2 were determined by the design team to best

accommodate the current client with additional consideration for future potentialcustomers. Marginal Values represent minimum metrics which must be met and IdealValues represent more ambitious metrics that would improve the quality and usefulnessof the product but are not vital for project success.

Table 3.2: Target design specifications

Metric # Metric Units Marginal

Value

Ideal

Value

1 Length ft


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4.0 Conclusion

Market research into currently available automated bean shelling machines indicates thata medium, not-for-profit farm would be unable to acquire such a device. These devicesare either too small or too large for the proposed application, and cost is typically

prohibitive in both cases. Due to the fact that most of these farms operate on a volunteerbasis, it is important that manpower be used efficiently. The consumption of 24 man-hours to accumulate only 3 quarts of beans is inefficient, and therefore necessitates suchan automated system. The implementation of a fully-automated bean desheller thatfunctions on the appropriate scale can greatly reduce the amount of wasted manpower ina medium farm environment. This system would be of great help to not-for-profits likeGood Earth, as well as independent farmers working to earn a living. Given therequirement for such a system, Team Green Bean has effectively established a set ofspecifications, constraints, and design criteria to effectively guide the conceptual designprocess.


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Works Cited

(n.d.). Retrieved November 16, 2011, from Homesteader's Supply:http://www.homesteadersupply.com/index.php?main_page=popup_image&pID=1214

Agriculture, U. S. (2011).Farms, Land in Farms, and Livestock Operations 2010Summary.National Agricultural Statistics Service.

Alibaba. (n.d.).Zhecheng Jingxin Manufacturing. Retrieved October 15, 2011, fromCaster Bean Sheller: http://jingangshi.en.alibaba.com/product/265897288-200410475/castor_bean_shelling_machine_0086_15238020786.html

Alibaba. (n.d.).Zhengzhou Amisy Trading Company site. Retrieved 10 15, 2011, fromRice hulling machine: http://www.alibaba.com/product-gs/241333057/Rice_husking_machine_rice_huller.html

Clever, P. (2011, September 29). Farm Manager. (T. G. Bean, Interviewer)

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