Designing & Operating a High Vacuum System

[jumbogala]

Homework Statement

I'm doing a project where I have to design a high vacuum system (just on paper).

I think I've figured out how all the parts hook up together, but I'm not sure how to operate the vacuum.

Homework Equations

The Attempt at a Solution

So I have a chamber connected to an oil diffusion pump. The chamber has an ionization gauge in it for measuring the pressure, and it has a vent valve.

Then there are supposed to be two valves in the connection between my chamber and my foreline trap. I don't understand why, can anyone explain?

My foreline trap has a thermocouple gauge in it and it is connected to a rotary pump.

So to make this thing work, what valves need to be open and closed? I think the vent valve needs to be opened to bring the pump to atmospheric pressure, then closed. Then I start up the oil diffusion pump? Or does the rotary pump go first? And when it's reached its lowest pressure, what valves do I open (after turning off the pumps, right?)

 

[denverdoc]

You might try posting this down in the general engineering forum where design problems are discussed a lot.

 

[jumbogala]

Okay, I will. Thanks!