A: So, the rough vacuum for the system is provided by a mechanical rotary vane pump, sealed with an oil that has a very low vapor pressure.
B: Makes sense.
A: This only gets us down to twenty microns or so. Our high vacuum pump works by spraying a jet of oil vapor downward through the vacuum chamber, which blows the extra air molecules out of the way.
B: Won’t the oil vapor jet kind of make the vacuum not a vacuum any more?
A: No, it’s fine. We condense it.
B: That sounds fake but ok.
A: So, we make all of our pipes and hoses very large in diameter, often more than 75 mm.
B: Doesn’t that make it clunky to fabricate and hard to keep airtight?
A: Yeah, but it’s necessary. You need big pipes for the vacuum to be able to flow through them fast enough.
B: I’m pretty sure that’s not how it works.
A: That is totally how it works.
B: Why is there a fan connected to our vacuum chamber? I thought fans only worked for moving atmospheric pressure air at low pressure differentials
A: It’s not a fan, it’s a turbo molecular pump. It only works at really high vacuum, but it basically just swats individual air molecules out of the way.
B: Okaaaaaaayyyy, so basically it’s an air molecule fan
A: It’s not a fan.
A: Let’s call this fitting style “Quick Flange”, or QF.
B: I vill kall it Kleine Flansche, because it ist so kleine.
C: (smoking dope) I will call it NW.
A: Why does it smell like honey and trees?
B: I’m mixing molten beeswax with rosin to make a vacuum sealant wax suitable for rough vacuum use (down to one micron or so)!
A: That’s a great idea!
A: (using a blowtorch to melt wax sealant coating that is the only thing making a hardware store water valve usable for vacuum) I had this thought. Suppose we went into business, making a special line of valves with metal bellows to make them usable for vacuum straight away?
B: And suppose we manufactured them out of some kind of super-material that, while hard to work with, is somehow cheaper than copper and bronze?
A: I dunno if it’s that good of an idea. With the low demand for such a thing, the prices would be through the roof. I can’t imagine many people buying that when they can just hack water pipe valves with bellows and wax.
B: Also, it’s not like anything could ever be cheaper than copper and bronze.
Explanation of Jokes below cut
A: OK HAV EYOU CONSIDERATED?
B: Go on?
A :HAVE YOU CONSIDERED: We’ll put a metal wire in the chamber
B: Won’t that make the volume smaller, therefore the pressure higher?
A : Well yes but HAVE YOU considered: Then we run a current through it
B: OK that sounds more scientific
A: We run a high current through it! So high that the wire starts evaporating a metal gas into the chamber! More gas equals lower pressure right?