Positive displacement liquid pump.

I invented this way back as a teenager. As a young adult I drew it out properly and paid for a provisional patent on it at Levin House, New Zealand, I happened to live not far from the National Patent office HQ at the time. It came about as I was mad keen on jetboats and saw a vane pump for an air horn, I adapted the design for liquids, providing locking 90 degree sections for intake, lock, outlet, lock. The intention was to machine it from metal. However the shape was beyond any minimal machining equipment I had and as a typical inventor, once I was able to visualise it's rotation I concluded that it was a valid concept and moved on to other projects, inventions, electronics, software etc.

Since then, with the reprap 3D printing project I got quite good using OPENSCAD and had a few goes mapping out the contours of the pump parts, especially the moving pin volume. I made several attempts at mapping this space including writing a donut surface mapping algorithm so I could extend it for mid disc and stroke adjustment. However it was very apparent that solving the slope contact of the pin leading or lagging contact surface required a bit more maths than I was comfortable with so I parked it again for most of this year. Then I had a crack at getting AI to solve it and although AI really got confused about what my clear instructions meant, it hulled pairs of pins along the path and this actually processed in OPENSCAD, I'd tried a similiar approach some years ago but the OPENSCAD render can now run in Manifold fast mode instead of CGAL which makes a big difference to rendering speed.

So last week I was quite stoked to complete the pump algorithm and 3D print it to have the pump functional in real life! There is more to the story. In my 20's the provisional patent was about to lapse and I was working for the major lift company that isn't Schindler or Kone. I presented them an option to buy up rights to my invention and use it themselves. Instead I got a nasty Lawyer's letter back claiming it as that company's property. I wrote right back informing them of their error!

Anyway, it's maybe comparable to a lobe or gear pump except there's no teeth meshing together, there are split pumping volumes and like a gear pump, it would be quite suitable for hydraulic pumping.

Note that the clearances are set to 0.15mm which allows a bit of liquid leakage but it's still close enough to see the potential of the pump. I find that flipping the pump halves upside down is a simple print, the rotor is a simple print and for the 4 pins, they print most accurately if you place supports at around 70 degeree angle and set them vertically.