The Impeller Pump is a simple example of a mechanism that is essential to industrialized society, but is almost never seen. Impeller pumps are found a garden fountains and basement sump pumps, water treatment plants, and anyplace else liquids need to be moved quickly and efficiently.

The principle behind the Impeller Pump is identical to the earlier Vacuum project. The FA-130 motor spins Impeller blades, imparting centripetal acceleration on the water and throwing it outwards at higher pressure. This high pressure water exits through the outlet. For and impeller pumps blades need to be submerged for it to function. So our little motor is going to getting wet in this project.

My knowledge of the complexities of and impeller pump is limited, so this project is a bit of an experiment. We're going to test what effect the diameter of the rotor has on the output of the pump.

The smallest pump has a rotor diameter of 20mm, the medium size pump had a 30mm rotor, and the large pump has a 40mm rotor.

The pumps outlets are all sized to accept a piece of 4mm tubing. To test the pumps, I timed how long it takes each one to move 1 liter of water from one container to another.

As a control, I used the 4mm tube to siphon 1 liter of water from one container to the other, which took 27 Minutes 8 Seconds, or 36 mL/Minute

The 20mm Pump moved 1 liter of water in 4 Minutes and 44 Seconds, or 211 mL/Minute

The 30mm Pump moved 1 liter of water in 5 Minutes 48 Seconds, or 172 mL/Minute

The 40mm Pump moved 1 liter of water in 9 Minutes 28 Seconds. or 105 mL/Minute

Alright, So all three of these pumps suck...

Its interesting that the pump with the smallest rotor diameter moved water the fastest. I speculate that the smaller rotor is accelerating less water at a time, letting it spin faster and move more water overall.

Download the Pump Files From Thingiverse: www.thingiverse.com/thing:545388

FA-130 Size Motor At Pololu: www.pololu.com/product/77