×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Using ordinary valves in vacuum

Using ordinary valves in vacuum

Using ordinary valves in vacuum

(OP)
I have a low pressure gas setup (typically operates 10-20 psi). Prior to operation, I need to evacuate the setup with a vacuum pump. The setup has various 2- and 3-way valves and stainless steel tubings. My question is if ordinary gas valves and vacuum are compatible. Since the valves are designed not to leak in pressure, I wonder if they may leak in vacuum. Thanks.

I have used vacuum valves before. They were sealed with corrugated baffle and quite bulky. The valves currently in my setup are 1/10 of the size.

RE: Using ordinary valves in vacuum

(OP)
How much leak can I tolerate?
The pump is turbomolecular type and is capable of 10e-8 torr. I am getting 10e-6. The setup is for the analysis of impurity gases with 0.1 to 1 ppm accuracy. Basically, if there is a room for improvement, I will take your suggestion. Thanks.

RE: Using ordinary valves in vacuum

You might find some dual seal valves that are better without going to metal bellows.
But positive pressure service valves will never make 10e-8.
I have tried.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources