approach – treadle pump

although both teams had similar (basic engineering) approaches to their projects, I want to give them each their own space.  I’ll do my best to elaborate a little bit on what each team did without boring you to death or being too repetitive.  today:  the treadle pump team.

Ann, Filipe, Jon and Peter took this approach, more-or-less in order, for the treadle pump design:

1. defined and weighted important design specifications – the team came up with 21 different design specs that they would use to design and evaluate their concepts.  these ranged from a weight of 10 for function/performance and for product upkeep (service, maintenance, reliability, operating costs) to a weight of 1 for quantity and for government regulations.
2. built ATC pump design – using the previously-developed treadle pump design manual (by university of michigan students), the team built their own ATC pump for testing and evaluation.  they found a few parts difficult to make, and found the final design to be somewhat difficult to operate, requiring a lot of strength.  the crux of the issue seemed to be the piston design.  other potential issues included material choice, overall height/ergonomics of the operating pump, and the lack of a leakage path past the pistons. 
3. researched existing designs available – the team investigated many different designs that they researched using the internet and other contacts they developed, including a Stanford PhD project that provided particular insight to the pumping mechanism.  by far, the most successful design is one called the MoneyMaker by a company named KickStart.  they sell the product quite successfully around the world in developing areas.
4. divided the overall system into seven main components (piston seals, valves, frame/base, treadles, linkages, mobility/stability, and intake filters) – this allowed the students to focus their efforts and understand the relative drawbacks and benefits of existing designs.
5. evaluated concepts for each main component – they brainstormed various different concepts for each of the main components identified.  some of the cool ideas they came up with included using old bicycles for parts of the frame, using a bicycle chain and gear as a pivot for the pistons, and using plumbing supplies for the overall construction.
6. refined focus of project to pump (pistons, seals, valves) – in the end after much investigation, the team decided to focus their efforts on the pump housing and functional innards, allowing the frame and treadles to be simple and similar to those already defined in the ATC design.  this is a possible subject for a future project, as ergonomics and local material availability/selection could surely by optimized if there was more time.
7. bought and extensively benchmarked KickStart MoneyMaker pump – the MoneyMaker is really the current state-of-the-art for treadle pumps.  the design has been produced and optimized by a company for many years, and is in use by hundreds of thousands of rural farmers throughout the world.  the students got their hands on one (despite it strictly not being made available in the U.S.) and benchmarked it as thoroughly as I have ever seen a product examined.  in addition to all the physicals of the pump and its parts, they evaluated performance and identified possible weak points for improvement.
8. modelled key performance elements mathematically – I must admit, I have not yet seen their modeling parameters or results, but I know that they have already looked at flow paths and theoretical output of the system.
9. built final product – i’ll save this for another time.