En1000: Projects in Engineering Design

Project Summary:

 

Our goal is to design a water pump and filtration mechanism that can be built economically and used anywhere in the world where there is access to basic materials like wood, scrap metal, and an old bicycle. We would like to tackle the problems of long-distance clean water access, at-home purification, water transportation in one, cost-effective device. The pump will be designed using components that can be easily sourced anywhere (an old bicycle, wood, scrap metal), as well as two more sophisticated components (a peristaltic-type pump and a UV filter), both of which can also be manufactured on-site or more easily distributed than an entire system from overseas.

 

 

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Introduction:

The problem that we're solving:

We are addressing the need for clean water access around the world through the use of a bicycle as a means of transportation and power generation. We will retrofit a bicycle to accommodate two water tanks and the power take-off necessary to mechanically power a pump and physical water filter and electrically power a UV filter.

 

The people who will benefit from this solution are communities around the world that are located far from water sources (potable or non-potable). Some of their specific needs are:

• Transportation to/from the water source
• Transportation for the water that they collect
• A means of pumping/collecting water from the source
• A means of purifying and storing that water for drinking or cooking
• A way to purify water (or re-purify water) at home

 

Background:

 

According to the UN, over half of the world's population currently live without access to adequate sanitation or clean water. A number of solutions to this enormous problem have emerged: new infrastructure development and new pipe access (the best possible solution), hand-pumps at the water site, and portable individual purifiers such as the LifeStraw. These (as well as other typical) solutions generally have the same problems:

a) significant time is necessary for development (i.e. building a pipeline or local hand-pump)

b) water is transported on foot, thereby limiting the amount that can be carried

c) they are personal-scale, when often one person per family (usually a woman) must bring water for an entire family

d) the solution is manufactured elsewhere in the world and cannot be maintained (or produced economically) where it is needed

e) purification is either at the site (poses a problem because storage containers are not reliably clean, so bacteria re-develops after some time at home)

f) purification uses expensive, non-renewable resources (i.e. oil/wood/coal stoves to boil)

 

 

Additional background information/research:

 

Check out our original Powerpoint presentation.

 

 

and web links to stuff I've found:

 

Innovate or Die Aquaduct

 

 

 

 

LifeStraw

 

 

 

 

Here is a list of things that I thing are good and bad about existing solutions:

 

Plus and Minus for the User:

	Pros	Cons
MayaPedal Bicycle Water Pump	Community-scale (5-10 GPM)	Stationary, no filtration
LifeStraw	Compact, inexpensive	Personal-scale
Innovate or Die Aquaduct	Family-scale, mobile	Expensive, integrated unit with proprietary parts

 

 

Intellectual Property:

 

So far, the Innovate or Die Aquaduct is what comes closest to our design. A few other searches didn't turn up any closely related devices, other than the MayaPedal concept of using bike power to pump water.

 

 

Proposed Solution:

 

We propose building a compact, bicycle-powered system that can collect, purify and transport water. In order to make our solution as accessible as possible, total manufacturing cost and materials availability will be considered as our most significant constraints.

We will design some kind of apparatus for any bicycle to fulfill the three goals of collection, purification and transportation. We will do this by using an old bicycle, an old bike rack, and readily available other parts (UV lamps, simple physical filters, tubing, etc).

 

 

Requirements:

1. Requirements: The apparatus will pump water and have mechanisms in place to power a pump and UV/particulate filters.
2. Constraints: The apparatus will be compact and easy to manufacture using readily available materials in any part of the world.
3. Evaluation criteria: We will pump water through our entire system (functioning physical and UV filters, as well as a functioning physical filter) and into our tanks.

    

 

 

Some initial drawings + flow diagram ideas:

EarlyRackMeasurementsDrawing

KickstandDesign

PreliminaryRackComponentLayour

LowerShelfMeasurements

 BackWheelBasicView2.JPG

MotorPumpDesign.JPG

RackDesign.JPG

 

 

 

 

Above: A rough sketch of the bike rack and necessary supports that were added.

 

Above: A preliminary diagram of how the back tire will drive the generator and pump. The belt idea was later abandoned in favor of a wheel that attached to a shared shaft between the engine and pump.

 

 

Above: A flow diagram of energy and water through the device. This is the final design.

 

 

Above: A drawing of the shared shaft/wheel design for the pump and generator. This is what we used in the final design.

 

Above: A design for a UV-LED water filter that could be manufactured simply using LEDs and black piping. This isn't what we used for a final filter, but an idea for the future.

 

First Prototype:

Brainstorms:

Here are the ideas I've come up with to build and test my solutions:

First Prototype: Our first prototype was made out of cardboard, tape, glue, nuts and bolts. We took measurements off of a bike in the lab (didn't have our final bike as yet) and built our original kickstand and lower shelf designs.

 

 

 

 

First Test and evaluation:

 

We didn't test this design with any water or loads; it was purely to have a 3D model to see how we would actually attach the apparatus to the bike and where problems would arise that we hadn't foreseen on paper.  With this model, we also explored how we would use rotating parts and pins to bear loads and add stability.

 

Parts list: Cardboard, masking tape, permanent glue-sticks, nuts and bolts.

Other equipment: Borrowed bicycle, drill press

 

 

Results:

Things that changed, problems, resolutions and other ideas:

 

• Our final wood shelf will resemble the shelf on the prototype
• Our final metal connector piece between the shelf and the bike will be much smaller (will not extend the full length of the rack, as it does now) because it's unnecessary and adds weight.
• Our final kickstand won't have the rotating feet on the sides to add stability, since one, straight piece would do this better.
• We won't use a belt to drive the generator and pump; we had originally thought of doing this by attaching a secondary rim to the back wheel and driving a belt off of that (connected to a shared shaft between the generator and pump). Instead, we're going to use a shopping-cart wheel that will directly contact and run off of the back wheel. A shared shaft between the generator and pump will run through the middle of the wheel

 

 

Second Prototype:

Brainstorms:

 

With our final bike donated from Recycle-A-Bike, we took final measurements and made our final drawings for the apparatus.

The final kickstand was made out of welded scrap steel, and attached to the bike with pieces of scrap steel angle, which were drilled to fit onto the bike according to our designs.

 

Second Test and evaluation:

• The rack fit well and the pin design held the bike up. The kickstand was designed to fit at at 90-degree angle to the ground when the bike was on the ground, instead of when the bike was off the ground (as it would be with the kickstand down). So when a rider sat on the bike with the kickstand down, the kickstand shifted backwards and looked like it would break under the weight and stress of a rider and power generation.
• We decided that we needed to add front supports to the shelf, which were welded to the bike frame and attached to the shelf via an integrated screw.

 

 

Results:

Good: the stand works and the shelf fits. But we needed to bend the kickstand so that it would transfer load perpendicularly to the ground when someone was riding, instead of shifting backwards.

 

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Final Results:

 Final Drive Wheel Attachment Diagram

Final PTO Diagram

The final shelf apparatus fit as anticipated and the bent kickstand idea also worked. The design and mounting of the motor/pump apparatus proved to be the most difficult part: different pieces of metal had to be drilled and cut to help stabilize the pump and motor, which were then ziptied and hose-clamped to the bike rack. A piece of wood was also cut to go underneath the motor to provide stability.

 

When the bike was tested for the first time, we found the following issues:

 

that we had to determine a fine balance between pumping too much water and not pumping enough to keep the whole machine working. We also found that because we'd tightened the pump too much to the rack, it cracked a little and water started to leak out.

 

When we pumped too much water through the system, a hose sprang loose and sprayed water everywhere, including on the motor (which then stopped working, even though it couldn't power the UV filter because of AC/DC conversion problems). Note for the future: build waterproof casing for all electric parts.

 

The UV filter could not, in the end, be powered by our motor, even though the motor did (pre-shower) generate the power we'd anticipated. The reason it didn't work was because the UV light requires an initial voltage of ~500V to start the UV light, and normal current of ~125V to maintain it. So our motor could keep a UV light going, but some other mechanism would have to start it up. For our presentation, we will plug the UV filter into the wall.

 

 

 

 

 

Materials:

 

Bike (donated from Recycle-a-Bike)

Rubber tubing (McMaster-Carr)

Gardening pump

UV Water filter (fishtank filter - Tetra)

Scrap wood

Scrap metal

Zip ties

Hose clamps

12V, 200RPM motor

Refrigerator water filter

Shopping cart wheel

Water tanks (2.5 gallon tanks, Stop and Shop)

 

Other equipment needed:

Welding equipment

Drill Press

 

 

 

 Notes/Future Work: 

•  Build waterproof housing for the motor
• Need to develop another way of powering the UV filter: perhaps the one we used was too sophisticated, and we'd be better off using something that we build, such as the UV LED idea that we explored (the diagram is up higher on this page). Though an initial concern about this was the sterilizing power that a homemade device (or LED device) might have, it turns out that UV LEDs are already being used for other anti-bacterial applications (see the dental tools that use Luxeon LEDs Luxeon LED Dental Bulbs (and other products)
• This project might have potential for use in emergency situations, such as in Burma or China right now. The more sophisticated components of the system (the UV filter, pump, piping) can be shipped as aid and combined with local bicycles, scrap wood and metal to provide a means of power generation and clean water supply (often one of the biggest problems after a natural disaster).
• Another secondary use of the filter would be at-home (or really, anywhere) power supply - you coudl disconnect the UV filter from the motor and use it to power any other simple electrical appliance.

 

 

 

 

 

 

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