Blower & Vacuum Best Practices, April 2017, by Tim Dugan.
http://www.blowervacuumbestpractices.com/technology/rough-vac/vacuum-system-fundamentals-compressed-air-people

"If you want to understand vacuum systems, you have to get out of the ruts, and slog through the mud and bounce over the rocks a bit.  If you’re a “compressed air person”, think outside the box for a few pages with me.  I am going to borrow some terms from the “pump people” to explain how vacuum systems are similar, yet different from compressed air systems. There are several ruts to get out of.  Remembering what changes and what doesn’t, what is controlled, and how to design systems for optimal energy consumption."