Thanks for the information about how these pumps work Steve. I have a few pics of them (Amateur Telescope Making vol 3) but I wondered how the oil was recycled in use, does it just pool down the bottom of the pump reservoir, with an exhaust higher up above the oil level to take the diffuse gases to the mechanical pump?. If anyone has a secondhand three stage available I would be very interested in buying one. The problem over here is such things are very hard to come by in Australia (along with Welch pumps) and Hamfests are non-existent in my neck of the woods so it's a matter of putting the feelers out or making it from scratch.
Created on Friday, March 30, 2001 11:55 PM EDT by Mark G Harriss