For a project ("Hydro do that?") at the Glasgow School of Art, our group of students was tasked with designing and manufacturing a water pump. The task was to be a competition betwixt several teams, each taking the name of an aquatic creature. Our designated company was 'Dolphin'. The winners of the competition were to be the group whose pump had the highest efficiency, and the pumps had to be able to pump five liters of water, through a height of 60cm (2 feet) in less that five minutes.

Our research and development led us to find that a piston pump would be the most effective way of pumping water.

We made three pump prototypes, to see which would be most effective at pumping water.
We built an axial impeller, a diaphragm pump and a piston pump.

The piston pump seemed to be the most viable solution to the efficiency problem, and our online research agreed with this, so we decided to build our final design in the form of a piston pump.

However, our brief required that we do testing and optimization for the pump, so we designed our pump to have three removable and interchangeable cylinders, to allow us to test the efficiency for different numbers of cylinders.

Materials Used:

2mm aluminium sheet
12mm plywood
3mm acrylic sheet
4mm mild steel rod
4x12x4mm bearings
24V, 5600 RPM electric motor
Clear plastic pipe (unknown origin)
Aluminium Bar
PVC pipe T-Joints
PVC plumbing pipe
Evian bottle necks and caps
Assorted screws, bolts, washers
hot glue
pipe cement
Plastic Weld (Dichloromethane

Reccomended Equipment:

Band saw (metal)
Band saw (wood)
Metal File
Sandpaper (various grit)
Metalwork Lathe
Pillar Drill
Cordless Drill
Assorted drill bits (including forstner / flat bits)
hot glue gun

Yeah, we used a lot of stuff on this project. The art school has a very well equipped workshop. One could probably substitute our pistons for something a bit more accessible, perhaps plastic and a standardized pipe size in order to make the whole task a bit less demanding in terms of equipment.

Step 1: Construct the Crank and Valves


We started the build by constructing the master/slave crank rod assembly. This was made out of aluminium sheet.  Two slave rods were cut, a master rod (which was essentially the slave rod, but with a larger circle on one end of it), and a spacer plate. The spacer plate and the circle were to form the central hub of the crank arrangement.  Each part had a 12mm hole drilled in the middle, and six smaller holes drilled around it, equally spaced to take the bolts that held the slave rods, and the whole assembly together.

The plates were spaced out by having an extra nut on the bolts in between the two plates.

Attaching the crank shaft was a bit of a fouter, as the crank had to be bent out of 4mm mild steel rod, but it had to be bent with the crank rod assembly already on it.
It was possible to bend one side first, then slide the crank rod assembly onto the shaft. Through use of a steel box-section jig, we were able to bend the other half of the crank and make it line up. The stroke on the pistons was 50mm, so the crank had to be offset by 25mm.


The two-part flapper valves were designed to fit the bottle caps we were using as the pipe attachment system. Since we needed all the valves to be the same, we had them laser cut from 3mm acrylic, and 0.5mm styrene.

We took measurements from the PVC T-joints, to make sure that we would laser cut the adapter pieces with the right inside diameter.

The valves worked by having two hinged semicircular flapper plated, hinged across the diameter of the pipe. The original valves had to be replaced because of a glitch whereby the two plated (sharing the same hinge hole) would overlap. This was solved by placing a strip between them, and stopping them overlapping.

<p>So, how did your pump perform in the competition? What kind of pumps did the other teams build? Was one type of pump noticably more efficient than the others?</p>
<p>Other pumps in the competition were rope, diaphragm, a single piston, as opposed to our triple radial. Another one I can't remember the name of.. The highest efficiency was about 12% for the rope pump which although incredibly low, is the record for efficiency on this pump project at the Art school, ours only got around 7% I think, but was one of the highest efficiencies out of all of the other pumps excluding the rope.</p>
<p>Although our pump did not win based on efficiency, our team was awarded with a prize for the most ingenious and impressive pump!</p>
<p>What was the reasoning to keep the output piping as three separate tubes? It would seem like you would get a more consistent flow if they merged into one.</p>
<p>does it have a fairly consistent output? it seems like it would, because one piston always seems to be compressing at any given moment.</p>
<p>What type of o-rings did you use? Where did you source them from?</p>
<p>I would look at http://www.mcmaster.com/</p>
<p>..Nice! :{)</p>
<p>good job :)</p>

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