Pipeline Pigging 1

[sewerfix]

Does anyone have experience with pigging of municipal sludge pipelines? in particular the use of welded bars in tee braches to stop pigs catching etc.
I'm concerned about the buildup of sludge / rags on such bars being a source of high maintenance.
Are there other tricks to ensure a foam pig travels past a tee brach and stays "on the right track"

I was thinking of a perhaps a three way ball valve with T-port to isolate the branch line - pig the valve.

Thanks
Andrew

 

[DrillerNic]

What about using a sphere tee?

 

[MTPipeliner]

Are your branches the same size as the main line?

We only use the pigging bars if the branch is 1/2 the mainline or bigger.

This is for nat gas, so I'm not sure if the same would be true of your system.

 

[zdas04]

Sewerfix,
I've seen the moral equivilant of your pigging bars over the inlet piping on seawater cooling systems. The bars collect an amazing accumulation of very nasty stuff. You are very correct in your concerns.

I'm assuming you are talking about parts of the system that are "pipeline" sizes. I can't imagine running pigs in a 6-foot diameter pipe.

For your application, I would tend to weld a "donut" shaped piece into the branch. To keep pressure drops under control I'd shoot for a 0.75 beta ratio (i.e. the I.D. of the hole should be 75% of the OD) so for a 8-inch branch, put a donut with a 6-inch hole. That should minimize the sludge concentration, minimize the permanant pressure loss, and effectively keep the pig on the straight and narrow. Make sure the hole in the plate is smooth and I'd chamfer both sides of the hole to minimize flow disruption.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[Cockroach]

Sewerfix, I just love your handle! Cute! LOL

I have a three way ball valve which acts as a pig launch for pipeline applications. Send me a link to "Sturni_Hueston@Yahoo.ca" and I will be happy to e-mail a return layout.

Hope this will work for you. Foam pigs are good, spherical ones work best I think, rags on the end of broom handles are right out!

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada