Hi everyone,

I have a vacuum furnace that can reach about 10^-5 mbar. On the KF flange, I currently have a capped tee. I want to build a system that, after pumping down the vacuum, allows me to fill the furnace with argon from a gas bottle through a pressure regulator (e.g., set to 0.5 bar), so the furnace atmosphere is argon instead of air.

Here’s the rough idea for the setup: vacuum furnace → KF tee → valve (e.g., ball valve) → pressure regulator → argon bottle

My questions:

• Will one valve be enough to maintain vacuum after closing?
• Could the pressure regulator cause gas to be sucked back into the bottle due to the vacuum?
• How to prevent vacuum pulling gas backward through the regulator?
• Should I use a check valve or another valve type for this?

Thanks for any tips or advice!