I want to try putting together a quick vacuum generator that runs off
compressed air (run of an 8 gallon tank up to 130 PSI.

I'll be using it for desoldering so I think I want a reasonably strong
vacuum, but the volume is not all that high. It will probably be used in
"burst mode" - with a burst of vacuum for a few seconds being needed
intermittently.

Heaps of googling and patent searching has turned up lots of commercial
products and on or two water powered vacuum generators but not much in the
way of pneumatic ones.

I'm hoping for a real quick & simple design - any build one or point me to
some plans?

thanks
D.