Two Air Pumps

myminifactory

Two Air Pumps are smaller 3D printed versions of much larger air / water pumps I built using PVC pipes and fittings when I was younger. The design is somewhat similar (although inverse in operation) to the 3D printed single cylinder air engine, with a single cylinder, a single piston, and dual openings for air intake. Instead of having a moving valve plate either leading or lagging the piston by 90 degrees to control air flow through the dual pressure and exhaust ports, this design utilizes a much simpler valve, an o-ring on the piston itself, and a single exhaust port, the plunger stem. I have included two versions of the air pump in Two Air Pumps, one short and one tall. The differences between the two (aside from one is shorter and one is taller) is that the taller version can move more air per stroke than the shorter version, requiring fewer pumping cycles to move the equivalent amount of air. If you have a taller format printer, I recommend printing the taller version; however, the shorter version easily produces enough air to inflate the "punch balloons" used in Four Whistles Version 2 and Balloon Powered Single Cylinder Air Engine Open Chassis. Assembling either air pump is via threaded connections. One of my goals when designing this model was to learn threads, so I incorporated threaded connections for a more secure assembly. The threads printed great with no additional scaling or support material required for a good, air-tight fit. To complete this model, you will need to purchase an "AS568 #222" o-ring (1 1/2" ID, 1 3/4" OD, 1/8" section), flexible gasket material (I've used thick cardboard, inner tubes, thick rubber gloves and 1.5mm thick shelf liner, which worked the best for me) and petroleum jelly (for lubrication of the o-ring piston valve). I also used scissors, a single bevel razor blade, a modeling knife, and a needle file set for assembly. As always, I probably forgot a few files or other tools, so if you have any questions, please don't hesitate to ask. I make plenty of mistakes. Designed using Autodesk Fusion 360, sliced with Cura 2.3.1, and printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended.