Alpha Prototype PresentationNov 4, 2008

Today’s Presentation:• System Schematic Review• Materials Analysis• Materials Processing • Tube Fabrication• Joints and Filter Designs• Tank Specifications• Alpha Prototype• Cost Analysis• Project Concerns/Plans for Beta Prototype

Schematic of Drip Pipe Irrigation System

1 m

(not to scale)

6 m

20 cm spacing between plants

Large Particle Filter

Water Tank

Materials Analysis• HDPE cheap & environmentally friendly.• HDPE bags widely available in Ethiopia.• HDPE bags Too light to be fed into grinding

machine.

Material Processing

• Two ways of making pellets out of plastic bags:

1. Heat (320 F) + Pressure (1000 Pounds) 20 bags to get thick solid sheets; Cut the sheet into smaller rectangular pieces to fed into grinding machine

Carver Press

2. Roll 6 plastic bags in a cylindrical shape and feed.

Shredded Plastic bags Grinding Machine

Tube Fabrication

• 75% LDPE pellets + 25% HDPE shredded bags by weight.

• Used Blown Film Processor

Blown Film Processor

Blown Film Processing

Fabrication Steps

1. Pour in the pellets into hopper

2. Blown film coming out from the circular die

Fabrication Steps (Continued)

3. The HDPE tube growing in length

4. Pulling at a constant rate to make long tubes

Initial SolidWorks Models:

Elbow Joint Y Joint

Prototype made with simpler joint designs made of HDPE

Initial Joints Designs

Alpha Prototype Joint Design

• Solid HDPE tubes with holes drilled in them.• Tube is affixed onto opening:– Superglue (bad seal)– Soldering iron (decent watertight seal)– Shrink wrap? (possible future consideration)

Filter Design

Alpha Prototype does not include the designed filter

Tank Specifications

• Original Plan: A 110 Liter Tank (3 water refills/day)– Sorghum Plants in 6m X 6m Plot– 230 Sorghum requires a maximum of 3-4 Inch of water/10

days (during its highest growth phase)– At the flow rate of 51 L/hour the plants needs to be

irrigated for 6.25 hours per day• The plot will require 320 L/day of water

• Prototype Tank: 2.5 Liter water jug (Smaller scale)

Alpha Prototype

• Tubes are inserted into the T and elbow joints.• Superglue, soldering iron is used in the

attachment of some tubes to ensure stability.• Smaller scale Drip Irrigation System• 2.5 Liter Water Tank

Cost Analysis• Total Cost = $ 2.69 per system• Materials Cost

– $0.85 for injection molded water tap– $0.80 for 48 feet of tubing (including 5% rejection rate)– $0.70 for joints, elbows

• Utilities Cost– $0.03 per system based on current costs of electricity

• Other Costs (Rent, Machinery, Delivery) – Not included– Rent = $14 per system– Sunk

• $77 per system after 1 years• $15 per system after 5 years• Problems include high costs of machinery

• Labor Costs – would have to be $0 to make this reasonable without much funding

Project Concerns

• Leaking of water from the joints• Some tube/ joints attachments less stable (use

of superglue)• Not 100% recyclable material• Tubes not straight (tend to curve)• Tube diameter not even throughout

Plans for Beta Prototype

• Better T and elbow joints• Better/more stable attachments of tubes to

the joints• Tube of uniform diameter • Greater number of tubes (a larger drip

irrigation system)• Fabrication of filter for grey water

Working Prototype is

Outside

Any Questions?

Initial Output Valve Design

3-D Printing currently presenting problems with assessing design.

2nd Generation Output Valve Design

Filter Material

•36in X 100 ft Charcoal Aluminum Screen for $82.00 a roll •Required filter area

would be 32 in2

•Allows for 1,375 filters at 6 cents a piece.

www.homedepot.com

Pressure Flow Calculations

efunda.com

3rd Generation Output Valve

3D Print of 2nd Generation Design