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 fo