TPU Check/One-Way Valves- No Moving Parts!- and a Demonstration Keyboard Duster (Hand Pump)

Check it out- I've designed several one-piece print-in-place TPU check valves- no BB or ball bearings needed, no moving parts to stick or wear out. One-piece elastomer check valves are common enough in the world, but I've never seen someone print one, so I took a crack at it, and it works very well. To give it a practical application, I've designed a simple squeeze-bulb keyboard duster (i.e an air pump) using two 'duckbill'-style valves, no moving parts at all, and it's very effective. 

I've included two valve types, both derived from commercial silicone check valves used in industry: A ‘duckbill’ valve, a good general-purpose design with low backflow/leakage, as well as a ‘cross-slit’ valve, designed to allow higher flow and for objects to be passed through it, i.e. a thermometer or probe, but which has more back-flow. I've found the duckbill style adequate for air valve applications, but include a specialized design to get people thinking in terms of what printed elastomers can do for this kind of thing. 

About the keyboard duster- I wanted to design a simple all-TPU no-moving-parts air pump, and a keyboard duster is the easiest there are four TPU components: the inlet and outlet valves, the squeeze bulb, and a nozzle that goes over the outlet valve and directs the blown air into a narrow jet that's ideal for dusting. The bulb is solid but is printed with light gyroidal infill, which makes it springy and forces it to refill with air every time you squeeze it. I do include a totally hollow bulb, for those who want to try that out, but it doesn't refill with air well so I don't recommend it. 

TWO IMPORTANT DUSTER NOTES: 
1) I highly recommend welding the seams after assembly- I used a soldering iron and it worked very well, although it looked a little sloppy. It works without welding the valves in but the inlet valve tends to pop off if you squeeze it too aggressively. Hopefully in the future I can revise the connections so you get an effective press-fit without welding. Just melt the seams together, I've designed the valves so there's excess material there to facilitate a weld without you needing to add any additional filament. 
2) the bulb will be sealed over at the inlet and outlet after printing; you must open both up, either by cutting a plug of TPU out with a fine hobby/surgical knife, or melting through it with a soldering iron. Cutting worked well and was a little tidier. 

And, of course, the usual TPU caveats apply- slower printing is safer. Stringing will be horrendous, so printing by object is highly recommended, and you'll likely need to use a hot air gun to get rid of any stray hairies. I use supports for the bulb and iirc the cross-valve design, these have been manually painted on and tested so you shouldn't have to play with any of that. 


Play around with this, and think about the potential applications for being able to integrate fully-printed-in-place one-way valves into designs. I can see one-piece print-in-place pump systems being a natural next step, and from there we can go in all sorts of interesting directions.