Does anyone have any drawings of the Welte rotary vacuum motor for
driving rolls, please?

I particularly would like to discover how the rotary valve and
associated ports work.  I am also assuming the large cast metal wheel
on the end is a kind of fly wheel, because the diameter of the circular
motion is quite small and I guess this wheel would smooth the rotation
somewhat?  I am planning to build one, but need to understand the rotary
valve.

Andrew Leach