Minor and Major barrel length for 20" pipeline receiver 1

Those sound huge - much longer than we use. Iv'e got several 16" launchers that have a 6 foot length and a catalog sheet from Sagebrush that lists a 20" as 78 3/4" long from flange to end of barrel.

For any launcher the throat (minor barrel) needs to be long enough to allow a pig to get started properly, but it doesn't have to be really long (you can't push a dry pig very far into the throat without serious help). 3-4 ft is about right on a 20-inch.

The [major] barrel should be long enough to accommodate normal pigs (6-7 ft is fine).

I recently saw an adaptation that I really liked. Some clever fellow put a set of flanges between the outboard pipe support and the closure. That allows him to unbolt the flange and drop in a pup long enough to accommodate a really long smart pig (and allows him to build the pup AFTER he knows the length of the smart pig he's going to run). This seems like the best of all possible worlds, wish I had thought of it. Building a launcher long enough to run smart pigs is not a great idea because it is really a pain to get a pig seated in the throat when the throat is 15 ft into the barrel every time you need to run the pig. Your shovel handle isn't long enough and it is hard to get enough force on the pig at that distance to make sure it starts.

David

We must be using shorter pigs. The owner uses smart pigs that can navigate standard long radius ells. He has not complained yet about the shortness of the barrels.

They seem to stack tools (with a neck between the tools that allows them to traverse many bends) to get different data, different resolution. I've seen 8-inch smart pigs that were 15 ft long. Basically if the pig will fit and the closure will close then the barrel is long enough. I've seen more than a few launchers/receivers that couldn't accomodate a smart pig (and I've seen ham-handed modifications that got people hurt).

David

I agree with zdas04 on building the launcher with the ability to easily change length. I design intelegent pigs and their lengths can vary greatly from company to company so making it easy to tailor fit the oversized portion will make your life easier in the long run.

Just don't forget to do the same on the receiver as well.

Regards

William

William G Callahan P.Eng
Pipeline Management Group
Baker Hughes Inc.

Good point. Have you seen this flange-pair idea before? When I saw it I was blown away until I noticed that the kicker line came in between the flange and the closure (so you needed a welder to extend the kicker line). Even though it was a poor implementation of a great idea, it was still a great idea.

David

We've used the flange idea before as well to allow for closure replacement when the closure gets beaten up or corrodes excessively. You can order the new one, bolt it up on the fly and keep running.

Thanks gentlemen for the discussion and ideas. Sharing knowledge makes the life easy. Thanks once again