Elmer Verburg's steam pump is one of his more fascinating models. Both the steam engine and the pump are double-acting for maximum power and smooth fluid flow. The power piston is directly connected to the pump piston so it can exert its full force on the pump.

This creates a problem with regard to driving a flywheel. Elmer solves it ingeniously by driving the flywheel with a ball jointed rod attached to the piston connecting rod. As an aside, this mechanism forces the pistons, power and pump, to oscillate in their respective cylinders thus averaging the wear. All in all, it's a fascinating little pump set that's fun to watch.

Here's a video of it in operation...



and here a slow-motion video to make the ball joint operation a bit easier to see...



The pump is pumping common mineral oil. Better than water, it prevents corrosion and lubricates the mechanism. I use it in all my pumps.