×
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

Poly-pig Trap

Poly-pig Trap

Poly-pig Trap

(OP)
My company has recently started using poly-pigs in order to remove the thermofluid inside.  We've been using them by inserting them into one end of the coil and blowing them through with 40 psi of compressed air.  I'm assuming that the fluid being pushed out by the pig is also undergoing the same 40 psi of pressure, as if it was a regular flow.  Is that correct?  Also, I've been tasked with designing a trap in order to catch the pig and allow the removed fluid to flow out.  I've basically designed a box that attaches to the coil and has a drainage pipe on the bottom.  My question is that when the box fills up with fluid and is going through the drainage pipe, will it still be under that same 40 psi?  Thank you in advance for any help.

RE: Poly-pig Trap

I believe your assumtions are wrong. Alot of that pressure energy used to move the pig is converted to heat energy via friction. The actual fluid pressure on the dowstream side of the pic will be <40psi.

RE: Poly-pig Trap

You didn't say what size line you are pigging.  If it is less than 8-inch then I'd look at something like the Argus Pigging valve instead of designing a new trap.

David

RE: Poly-pig Trap

There are commercially available pig traps, but I can't remember any names.  M-Co, I think is one of the small co's.  A bunch of oil pipeline fabricators make them.  Aceco makes pigging valves if you would rather go that route (acecovalves.com).

Most pipeline pig traps are just a straight run of slightly larger pipe, continuing past a "T" where the pipeline turns away at 90 deg.  The far end of pig trap is connected downstream ("vented" back to the pipeline) so there is flow/pressure to push the pigs into it.  Valves are installed to allow you to open & close the system.

-----T--X-- pig catching chamber ---) closure
     | valve                       |
     |                             | vent line
     |                             X valve
     |_____main pipe_______________|____________

 

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