Smart questions
Smart answers
Smart people
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Member Login




Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips now!
  • 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!

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

Donate Today!

Do you enjoy these
technical forums?
Donate Today! Click Here

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

1PE (Civil/Environmental)
26 Feb 04 9:19
I'm designing a large diameter siphon to dewater a deep mine pool. I am currently considering 12" diameter DR 11 HDPE Pipe with fused connections.

My first question is this "If I break or lose siphon will the pipe have a good potential to collapse?"

Secondly, the siphon will be operating at a minimum pressure of about negative 11 psi. Are there adjustable vacuum release valves available which can be set to operate at a negative pressure of 11 psi and release the vacuum at a setting of say negative 15 psi?

Thanks in advance for any responses.
smckennz (Mechanical)
26 Feb 04 18:20
If DR is the diameter divided by the wall thickness, the 50 year critical buckling pressure for unsupported PE80B is 476kPa. This gives a reasonable safety factor over the full vacuum differential of 100kPa. A safety factor of 2 to 2.5 is often recommended, and in this case it is 4.76 So it wont suck flat.

Bleeding air in to control vacuum is dodgy at best; unless velocities are high enough to sweep away the air, you run the risk of losing prime.

Cheers

Steve
Ag93 (Mechanical)
2 Mar 04 23:55
1PE,

Check out our website, www.performancepipe.com.  Request an engineering CD.  There are some calculations for unconstrained buckling on the CD plus many more design calcs.  If you have questions call me.

Kevin Deal
Performance Pipe
936-321-8940

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!

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close